Stephen William Smith

Journal Article Ultrasonic imaging · July 2014 We developed new forward-viewing matrix transducers consisting of double ring arrays of 118 total PZT elements integrated into catheters used to deploy medical interventional devices. Our goal is 3D ultrasound guidance of medical device implantation to red ... Full text Cite

Acoustic radiation force impulse imaging (ARFI) on an IVUS circular array.

Journal Article Ultrasonic imaging · April 2014 Our long-term goal is the detection and characterization of vulnerable plaque in the coronary arteries of the heart using intravascular ultrasound (IVUS) catheters. Vulnerable plaque, characterized by a thin fibrous cap and a soft, lipid-rich necrotic core ... Full text Open Access Cite

3-D transcranial ultrasound imaging with bilateral phase aberration correction of multiple isoplanatic patches: a pilot human study with microbubble contrast enhancement.

Journal Article Ultrasound Med Biol · January 2014 With stroke currently the second-leading cause of death globally, and 87% of all strokes classified as ischemic, the development of a fast, accessible, cost-effective approach for imaging occlusive stroke could have a significant impact on health care outc ... Full text Link to item Cite

Refraction correction in 3D transcranial ultrasound imaging.

Journal Article Ultrasonic imaging · January 2014 We present the first correction of refraction in three-dimensional (3D) ultrasound imaging using an iterative approach that traces propagation paths through a two-layer planar tissue model, applying Snell's law in 3D. This approach is applied to real-time ... Full text Cite

Acoustic radiation force impulse imaging on an IVUS circular array

Conference IEEE International Ultrasonics Symposium, IUS · December 1, 2013 Our long-term goal is the detection and characterization of vulnerable plaque in the coronary arteries of the heart using IVUS catheters. Vulnerable plaque, characterized by a thin fibrous cap and a soft, lipid-rich, necrotic core is a pre-cursor to heart ... Full text Cite

Simultaneous bilateral real-time 3-d transcranial ultrasound imaging at 1 MHz through poor acoustic windows.

Journal Article Ultrasound Med Biol · April 2013 Ultrasound imaging has been proposed as a rapid, portable alternative imaging modality to examine stroke patients in pre-hospital or emergency room settings. However, in performing transcranial ultrasound examinations, 8%-29% of patients in a general popul ... Full text Link to item Cite

Pitch-catch phase aberration correction of multiple isoplanatic patches for 3-D transcranial ultrasound imaging.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · March 2013 Having previously presented the ultrasound brain helmet, a system for simultaneous 3-D ultrasound imaging via both temporal bone acoustic windows, the scanning geometry of this system is utilized to allow each matrix array to serve as a correction source f ... Full text Cite

Intracranial dual-mode IVUS and hyperthermia using circular arrays: preliminary experiments.

Journal Article Ultrason Imaging · January 2013 In this study, we investigated the feasibility of using 3.5-Fr (3 Fr = 1 mm) circular phased-array intravascular ultrasound (IVUS) catheters for minimally invasive, image-guided hyperthermia treatment of tumors in the brain. Feasibility was demonstrated in ... Full text Link to item Cite

Multiple isoplanatic patch phase aberration correction in real-time 3D transcranial ultrasound

Journal Article IEEE International Ultrasonics Symposium, IUS · December 1, 2012 We present an approach for correcting multiple distinct aberrators within a single transcranial imaging volume, i.e. several isoplanatic patches. Aberration is estimated using cross-correlation of RF channel signals followed by least mean squares solution ... Full text Cite

Ring array transducers for real-time 3-D imaging of an atrial septal occluder.

Journal Article Ultrasound in medicine & biology · August 2012 We developed new miniature ring array transducers integrated into interventional device catheters such as used to deploy atrial septal occluders. Each ring array consisted of 55 elements operating near 5 MHz with interelement spacing of 0.20 mm. It was con ... Full text Cite

Magnetic resonance microscopy

Chapter · January 1, 2012 Visualization of internal structures of opaque biologic objects is essential in many biomedical studies. Limited by the penetration depth of the probing sources (photons and electrons) and the lack of endogenous contrast, conventional forms of microscopy s ... Full text Cite

Intracranial dual-mode IVUS and hyperthermia using circular arrays

Conference IEEE International Ultrasonics Symposium, IUS · December 1, 2011 In this study, we investigated the feasibility of using 3.5-Fr circular phased array IVUS catheters for minimally invasive, image-guided hyperthermia treatment of tumors in the brain. Feasibility was demonstrated in two ways: 1) by fitting a 3.5-Fr IVUS ca ... Full text Cite

2D ring array transducers for real-time 3D imaging of atrial septal defect repair

Journal Article IEEE International Ultrasonics Symposium, IUS · December 1, 2011 We developed new miniature 2D array ring transducers integrated into interventional device catheters such as deploy atrial septal occluders. One transducer consisted of 55 elements operating near 5 MHz. The interelement spacing is 0.20 mm. It was construct ... Full text Cite

Pitch-catch phase aberration correction for 3D ultrasound brain helmet

Journal Article IEEE International Ultrasonics Symposium, IUS · December 1, 2011 Having previously presented a system for simultaneous 3D ultrasound imaging via both temporal bone acoustic windows, we take advantage of this system's scanning geometry to allow each matrix array to serve as a correction source for the opposing array. Abe ... Full text Cite

Dual-mode IVUS transducer for image-guided brain therapy: preliminary experiments.

Journal Article Ultrasound Med Biol · October 2011 In this study, we investigated the feasibility of using 3.5-Fr intravascular ultrasound (IVUS) catheters for minimally-invasive, image-guided hyperthermia treatment of tumors in the brain. Feasibility was demonstrated by: (1) retro-fitting a commercial 3.5 ... Full text Link to item Cite

Progress in ring array transducers for real-time 3D ultrasound guidance of cardiac interventional devices.

Journal Article Ultrasonic imaging · July 2011 As a treatment for aortic stenosis, several companies have recently introduced prosthetic heart valves designed to be deployed through a catheter using an intravenous or transapical approach. This procedure can either take the place of open heart surgery w ... Full text Cite

The ultrasound brain helmet: new transducers and volume registration for in vivo simultaneous multi-transducer 3-D transcranial imaging.

Journal Article IEEE Trans Ultrason Ferroelectr Freq Control · June 2011 Because stroke remains an important and time-sensitive health concern in developed nations, we present a system capable of fusing 3-D transcranial ultrasound volumes acquired from two sides of the head. This system uses custom sparse array transducers buil ... Full text Link to item Cite

Homocysteine-lowering and cardiovascular disease outcomes in kidney transplant recipients: primary results from the Folic Acid for Vascular Outcome Reduction in Transplantation trial.

Journal Article Circulation · April 26, 2011 BACKGROUND: Kidney transplant recipients, like other patients with chronic kidney disease, experience excess risk of cardiovascular disease and elevated total homocysteine concentrations. Observational studies of patients with chronic kidney disease sugges ... Full text Link to item Cite

Erratum: Dual-mode IVUS catheter for intracranial image-guided hyperthermia: Feasibility study (IEEE Trans. Ultrason. Ferroelectr. Freq. Control)

Journal Article IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control · January 1, 2011 Full text Cite

Erratum: Progress in ring array transducers for real-time 3D ultrasound guidance of cardiac interventional devices (Ultrasonic Imaging (2011) 33 (197-204)

Journal Article Ultrasonic Imaging · January 1, 2011 Cite

Double Ring Array Catheter for In Vivo Real-Time 3D Ultrasound.

Acoustic radiation force impulse imaging (ARFI) on an IVUS circular array.

3-D transcranial ultrasound imaging with bilateral phase aberration correction of multiple isoplanatic patches: a pilot human study with microbubble contrast enhancement.

Refraction correction in 3D transcranial ultrasound imaging.

Acoustic radiation force impulse imaging on an IVUS circular array

Simultaneous bilateral real-time 3-d transcranial ultrasound imaging at 1 MHz through poor acoustic windows.

Pitch-catch phase aberration correction of multiple isoplanatic patches for 3-D transcranial ultrasound imaging.

Intracranial dual-mode IVUS and hyperthermia using circular arrays: preliminary experiments.

Multiple isoplanatic patch phase aberration correction in real-time 3D transcranial ultrasound

Ring array transducers for real-time 3-D imaging of an atrial septal occluder.

Magnetic resonance microscopy

Intracranial dual-mode IVUS and hyperthermia using circular arrays

2D ring array transducers for real-time 3D imaging of atrial septal defect repair

Pitch-catch phase aberration correction for 3D ultrasound brain helmet

Dual-mode IVUS transducer for image-guided brain therapy: preliminary experiments.

Progress in ring array transducers for real-time 3D ultrasound guidance of cardiac interventional devices.

The ultrasound brain helmet: new transducers and volume registration for in vivo simultaneous multi-transducer 3-D transcranial imaging.

Homocysteine-lowering and cardiovascular disease outcomes in kidney transplant recipients: primary results from the Folic Acid for Vascular Outcome Reduction in Transplantation trial.

Erratum: Dual-mode IVUS catheter for intracranial image-guided hyperthermia: Feasibility study (IEEE Trans. Ultrason. Ferroelectr. Freq. Control)

Journal Article IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control · January 1, 2011 Full text Cite

Erratum: Progress in ring array transducers for real-time 3D ultrasound guidance of cardiac interventional devices (Ultrasonic Imaging (2011) 33 (197-204)

Journal Article Ultrasonic Imaging · January 1, 2011 Cite

Clinical prototype of autonomous breast biopsy robot guided by 4Dultrasound

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2010 Our laboratory previously conducted feasibility studies of autonomousrobotic breast biopsy guided by 4D ultrasound. Using a complete 3D image volume,processed by elementary thresholding algorithms with no human intervention, therobot was able to successful ... Full text Cite

Dual matrix arrays integrated into scanner for increased SNR of ultrasound brain helmet

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2010 In response to the high prevalence of stroke, we propose a system for scanning simultaneously via both temporal bone windows. The characteristics of this window and system limitations guide the design of custom matrix arrays. We present operational arrays ... Full text Cite

Intracranial dual-mode IVUS transducer for image-guided brain therapypreliminary experiments

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2010 In this study, we investigated the feasibility of using 3.5-Fr IVUScatheters for minimally-invasive, image-guided hyperthermia treatment of tumorsin the brain. Feasibility is demonstrated in two ways: 1) by fitting a 3.5-FrIVUS catheter with a 5 × 0.5 × 0. ... Full text Cite

Ring array transducers for real-time 3D ultrasound guidance of prostheticheart valve deployment

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2010 We have previously developed 2D ring array transducers for real-timevolumetric imaging guidance of minimally invasive procedures. These transducerswere integrated with an 11 French catheter sheath of a Cook Medical, Inc. venacava filter deployment kit. We ... Full text Cite

Dual-mode IVUS catheter for intracranial image-guided hyperthermia: feasibility study.

Journal Article IEEE Trans Ultrason Ferroelectr Freq Control · November 2010 In this study, we investigated the feasibility of modifying 3-Fr IVUS catheters in several designs to potentially achieve minimally-invasive, endovascular access for image-guided ultrasound hyperthermia treatment of tumors in the brain. Using a plane wave ... Full text Link to item Cite

Simulation of autonomous robotic multiple-core biopsy by 3D ultrasound guidance.

Journal Article Ultrasonic imaging · April 2010 An autonomous multiple-core biopsy system guided by real-time 3D ultrasound and operated by a robotic arm with 6+1 degrees of freedom has been developed. Using a specimen of turkey breast as a tissue phantom, our system was able to first autonomously locat ... Full text Cite

Three-dimensional ultrasound guidance of autonomous robotic breast biopsy: feasibility study.

Journal Article Ultrasound in medicine & biology · January 2010 Feasibility studies of autonomous robot biopsies in tissue have been conducted using real-time three-dimensional (3-D) ultrasound combined with simple thresholding algorithms. The robot first autonomously processed 3-D image volumes received from the ultra ... Full text Cite

Comparison of 3-D multi-lag cross- correlation and speckle brightness aberration correction algorithms on static and moving targets.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · October 2009 Phase correction has the potential to increase the image quality of 3-D ultrasound, especially transcranial ultrasound. We implemented and compared 2 algorithms for aberration correction, multi-lag cross-correlation and speckle brightness, using static and ... Full text Cite

New fabrication techniques for ring-array transducers for real-time 3D intravascular ultrasound.

Journal Article Ultrasonic imaging · October 2009 We have previously described miniature 2D array transducers integrated into a Cook Medical, Inc. vena cava filter deployment device. While functional, the fabrication technique was very labor intensive and did not lend itself well to efficient fabrication ... Full text Cite

Intracranial catheter for integrated 3D ultrasound imaging & hyperthermia: Feasibility study

Conference AIP Conference Proceedings · July 21, 2009 In this study, we investigated the feasibility of an intracranial catheter transducer capable of real-time 3D (RT3D) imaging and ultrasound hyperthermia, for application in the visualization and treatment of tumors in the brain. We designed and constructed ... Full text Cite

3-D ultrasound guidance of autonomous robot for location of ferrous shrapnel.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · July 2009 Vibrations can be induced in ferromagnetic shrapnel by a variable electromagnet. Real time 3-D color Doppler ultrasound located the induced motion in a needle fragment and determined its 3-D position in the scanner coordinates. This information was used to ... Full text Cite

Real time 3D ultrasound in guidance of autonomous surgical robot for shrapnel detection and breast biopsy.

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · June 19, 2009 Two studies have been conducted using real time 3D ultrasound and an automated robot system for carrying out surgical tasks. The first task is to perform a breast lesion biopsy automatically after detection by ultrasound. Combining 3D ultrasound with tradi ... Full text Cite

2D array transducers for real-time 3D ultrasound guidance of interventional devices

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · June 19, 2009 We describe catheter ring arrays for real-time 3D ultrasound guidance of devices such as vascular grafts, heart valves and vena cava filters. We have constructed several prototypes operating at 5 MHz and consisting of 54 elements using the W.L. Gore & Asso ... Full text Cite

Dual-mode intracranial catheter integrating 3D ultrasound imaging and hyperthermia for neuro-oncology: feasibility study.

Journal Article Ultrason Imaging · April 2009 In this study, we investigated the feasibility of an intracranial catheter transducer with dual-mode capability of real-time 3D (RT3D) imaging and ultrasound hyperthermia, for application in the visualization and treatment of tumors in the brain. Feasibili ... Full text Link to item Cite

The ultrasound brain helmet: feasibility study of multiple simultaneous 3D scans of cerebral vasculature.

Journal Article Ultrasound Med Biol · February 2009 We describe early stage experiments to test the feasibility of an ultrasound brain helmet to produce multiple simultaneous real-time three-dimensional (3D) scans of the cerebral vasculature from temporal and suboccipital acoustic windows of the skull. The ... Full text Link to item Cite

The ultrasound brain helmet for 3D transcranial Doppler imaging

Journal Article Proceedings - IEEE Ultrasonics Symposium · 2009 Transcranial Doppler imaging with contrast enhancement is a promising approach for visualizing a variety of cerebrovascular diseases requiring rapid treatment to minimize long-term effects. To address the time-sensitive nature of these diseases, we present ... Full text Cite

Dual-mode intracranial catheters for minimally-invasive neuro-oncology feasibility study

Journal Article Proceedings - IEEE Ultrasonics Symposium · January 1, 2009 In this study, we investigated the feasibility of dual-mode intracranial catheter transducers for visualization and treatment of tumors in the brain. Feasibility is demonstrated in two ways: 1) by developing a 12 Fr, integrated matrix and linear array cath ... Full text Cite

New ring array transducers for real-time 3D intravascular ultrasound

Journal Article Proceedings - IEEE Ultrasonics Symposium · January 1, 2009 We have developed new miniature 2D array transducers integrated into a Cook Medical, Inc. vena cava filter deployment device. One transducer consists of 55 elements operating near 5 MHz. The interelement spacing is 0.20mm. It was constructed on a flat piec ... Full text Cite

Color Doppler imaging of cardiac catheters using vibrating motors.

Journal Article Ultrason Imaging · October 2008 A miniature motor rotating at 11,000 rpm was attached onto the proximal end of cardiac electrophysiological (EP) catheters in order to produce vibrations at the tip that were then visualized by color Doppler on ultrasound scanners. The catheter tip was ima ... Full text Link to item Cite

Real-time 3-D ultrasound guidance of interventional devices.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · September 2008 We have previously developed 2-D array transducers for many real-time volumetric imaging applications. These applications include transducers operating up to 7 MHz for transthoracic imaging, up to 15 MHz for intracardiac echocardiography (ICE), 5 MHz for t ... Full text Cite

Real-time 3-D contrast-enhanced transcranial ultrasound and aberration correction.

Journal Article Ultrasound Med Biol · September 2008 Contrast-enhanced (CE) transcranial ultrasound (US) and reconstructed 3-D transcranial ultrasound have shown advantages over traditional methods in a variety of cerebrovascular diseases. We present the results from a novel ultrasound technique, namely real ... Full text Link to item Cite

3-D ultrasound guidance of surgical robotics using catheter transducers: feasibility study.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · May 2008 The goal of this study was to test the feasibility of using a real-time 3-D (RT3D) ultrasound scanner with matrix array catheter probes to guide a surgical robot. We tested the accuracy of using 3-D catheter transducers with the 3-D measurement software of ... Full text Cite

Intracardiac echocardiography and acoustic radiation force impulse imaging of a dynamic ex vivo ovine heart model.

Journal Article Ultrasonic imaging · April 2008 Intracardiac echocardiography (ICE) has demonstrated utility in providing high-resolution cardiac ultrasound images for guidance of numerous catheter-based interventions, including radiofrequency ablations (RFA). However, the training of interventionalists ... Full text Cite

Vibrating interventional device detection using real-time 3-D color Doppler.

Journal Article IEEE Trans Ultrason Ferroelectr Freq Control · 2008 Ultrasound image guidance of interventional devices during minimally invasive surgery provides the clinician with improved soft tissue contrast while reducing ionizing radiation exposure. One problem with ultrasound image guidance is poor visualization of ... Full text Link to item Cite

Piezoelectric vibrating needle and catheter for enhancing ultrasound-guided peripheral nerve blocks.

Journal Article Anesth Analg · December 2007 Ultrasound imaging has been used for performing single-injection peripheral nerve blocks and continuous catheters. One limitation with current technology is the inability to confirm the location of the needle or catheter tip. We describe a new needle and c ... Full text Link to item Cite

Vibrating interventional device detection using real-time 3D color doppler

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2007 We have previously described guidance of several interventional devices using a real time 3D (RT3D) ultrasound system with 3D color Doppler combined with the ColorMark technology. We then developed an analytical model for a vibrating needle to maximize the ... Full text Cite

3-D ultrasound guidance of surgical robotics: Autonomous guidance and catheter transducers

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2007 In 2006 our laboratory showed that a matrix array endoscope capable of real-time 3D (RT3D) scanning could be used to guide a surgical robot with an rms error of less than 2mm. In this study, we examine two new topics in robotic guidance: (1) the feasibilit ... Full text Cite

Ultrasound probe with integrated ECG lead

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2007 We integrated electrocardiogram (ECG) leads onto the face of a cardiac ultrasound transducer and the exterior chassis of a simulated small, portable scanner to minimize the number of devices needed to collect cardiac information. Since the ECG leads were n ... Full text Cite

Combined 2D array transducers/deployment kits for real-time 3D ultrasound guidance of interventional devices

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2007 We have described and fabricated 2D array transducers for many real-time volumetric imaging applications. These applications include transducers operating up to 7 MHz for transthoracic imaging,1-3 up to 15 MHz for intracardiac echocardiography (ICE),4-6 5 ... Full text Cite

Intracranial catheter for integrated 3D ultrasound imaging & hyperthermia: Feasibility study

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2007 In this study, we investigate the feasibility of developing an intracranial catheter transducer capable of real time 3D (RT3D) imaging and ultrasound hyperthermia, for application in the visualization and treatment of tumors in the brain. Feasibility is de ... Full text Cite

Real time stereo 3D ultrasound

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2007 Real time 3D ultrasound was developed at Duke University in 1991. Methods for displaying the 3D pyramid of data acquired by the system include selecting 2D image slices or integrating data into a volume rendered view. A third method, real time stereo 3D im ... Full text Cite

Autonomous surgical robotics using 3-D ultrasound guidance: feasibility study.

Journal Article Ultrasonic imaging · October 2007 The goal of this study was to test the feasibility of using a real-time 3D (RT3D) ultrasound scanner with a transthoracic matrix array transducer probe to guide an autonomous surgical robot. Employing a fiducial alignment mark on the transducer to orient t ... Full text Cite

Analysis of a vibrating interventional device to improve 3-D colormark tracking.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · August 2007 Ultrasound guidance of interventional devices during minimally invasive surgical procedures has been investigated by many researchers. Previously, we extended the methods used by the Colormark tracking system to several interventional devices using a real- ... Full text Cite

Real-time 3-D intracranial ultrasound with an endoscopic matrix array transducer

Journal Article Ultrasound In Medicine And Biology · August 2007 A transducer originally designed for transesophageal echocardiography (TEE) was adapted for real-time volumetric endoscopic imaging of the brain. The transducer consists of a 36 x 36 array with an interelement spacing of 0.18 mm. There are 504 transmitting ... Cite

Ultrasound probe with integrated ECG lead: feasibility study.

Journal Article Ultrasonic imaging · July 2007 We integrated electrocardiogram (ECG) leads onto the face of a cardiac ultrasound transducer and the exterior chassis of a simulated small, portable scanner to minimize the number of devices needed to collect cardiac information. Since the ECG leads were n ... Full text Cite

Real-time three-dimensional transesophageal echocardiography for guiding interventional electrophysiology: feasibility study.

Journal Article Ultrason Imaging · July 2007 At present, there are limited methods of acquiring three-dimensional visualization of cardiac structure and function in real-time during interventional electrophysiology procedures. Images acquired for integration of computerized tomography and magnetic re ... Full text Link to item Cite

Real-time 3D contrast-enhanced transcranial ultrasound

Journal Article Proceedings - IEEE Ultrasonics Symposium · 2007 Contrast-enhanced (CE) transcranial ultrasound (US) and reconstructed 3D transcranial ultrasound have shown advantages over traditional methods in a variety of cerebrovascular diseases. We present the results from a novel ultrasound technique, namely real- ... Full text Cite

Integrated endoscope for real-time 3D ultrasound imaging and hyperthermia: feasibility study.

Journal Article Ultrasonic imaging · January 2007 The goal of this research is to determine the feasibility of using a single endoscopic probe for the combined purpose of real-time 3D (RT3D) ultrasound imaging of a target organ and the delivery of ultrasound therapy to facilitate the absorption of compoun ... Full text Cite

3D acoustic radiation force impulse (ARFI) imaging using a 2d matrix array: Feasibility study

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2006 Acoustic radiation force impulse (ARFI) imaging has been reported as a successful method of measuring mechanical properties of tissue. Current methods use linear arrays to obtain a 2D image of tissue displacement. In this study, we have modified our real-t ... Full text Cite

Phase aberration correction on a 3D ultrasound scanner using RF speckle from moving targets

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2006 In 1992, Zhao et al. described a variation of the speckle-brightness algorithm for phase correction on moving targets [1, 2]. By subtracting two beam-summed consecutive interrogations of a region of interest, they were able to remove effects of reverberati ... Full text Cite

Ex Vivo acoustic radiation force impulse imaging of an ovine heart model

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2006 Acoustic radiation force impulse (ARFI) imaging with an intra-cardiac probe has been demonstrated to be a suitable modality to monitor the progress of radiofre-quency ablation (RFA) procedures. In order to continue studies while allowing increased control ... Full text Cite

Integrated endoscope for real-time 3D ultrasound imaging and hyperthermia: A feasibility study

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2006 The goal of this research is to determine the feasibility of using a single endoscopic probe for the combined purpose of real-time 3D (RT3D) ultrasound imaging of a target organ and the delivery of ultrasound hyperthermia to facilitate the absorption of co ... Full text Cite

3-D ultrasound guidance of surgical robotics: A feasibility study

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2006 The integration of real-time three-dimensional (RT3D) laparoscopic ultrasound with recent advances in robotic surgery can increase automation and ease of use for surgery in general, gynecological, and urological procedures. In this study, the 3D measuremen ... Full text Cite

Analysis of a vibrating interventional device for 3D colormark tracking

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2006 Ultrasound guidance of interventional devices during minimally invasive surgical procedures has been investigated by many researchers. Previously, we extended the methods used by the ColorMark tracking system to several interventional devices using a real- ... Full text Cite

Two dimensional arrays for real time 3D intracranial imaging of the brain

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2006 We have described and fabricated 2D array transducers for many real time volumetric imaging applications. These applications include transducers operating up to 5 MHz for transthoracic imaging, up to 15 MHz for intracardiac echocardiography (ICE), 5 MHz fo ... Full text Cite

3-D ultrasound guidance of surgical robotics: a feasibility study.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · November 2006 Laparoscopic ultrasound has seen increased use as a surgical aide in general, gynecological, and urological procedures. The application of real-time, three-dimensional (RT3D) ultrasound to these laparoscopic procedures may increase information available to ... Full text Cite

Real-time stereo 3D ultrasound.

Journal Article Ultrasonic imaging · October 2006 Real-time 3D ultrasound was developed at Duke University in 1991 and has since been used with a variety of transducers and shown effectiveness in clinical applications and in vivo animal imaging studies. Methods for displaying the 3D pyramid of data acquir ... Full text Cite

Phase-aberration correction with a 3-D ultrasound scanner: feasibility study.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · August 2006 We tested the feasibility of using adaptive imaging, namely phase-aberration correction, with two-dimensional (2-D) arrays and real-time, 3-D ultrasound. Because of the high spatial frequency content of aberrators, 2-D arrays, which generally have smaller ... Full text Cite

Integrated interventional devices for real time 3D ultrasound imaging and therapy

Journal Article AIP Conference Proceedings · May 8, 2006 Two recent advances have expanded the potential of medical ultrasound: the introduction of real-time 3-D ultrasound imaging with catheter, transesophageal and laparoscopic probes and the development of interventional ultrasound therapeutic systems for focu ... Full text Cite

Ultrasound: Transducers

Chapter · January 1, 2006 An ultrasound transducer generates acoustic waves by converting magnetic, thermal, and electrical energy into mechanical energy. The most efficient technique for medical ultrasound uses the piezoelectric effect, which was first demonstrated in 1880 by Jacq ... Cite

Real-time, 3-D ultrasound with multiple transducer arrays.

Journal Article IEEE Trans Ultrason Ferroelectr Freq Control · January 2006 Modifications were made to a commercial real-time, three-dimensional (3-D) ultrasound system for near simultaneous 3-D scanning with two matrix array transducers. As a first illustration, a transducer cable assembly was modified to incorporate two independ ... Full text Link to item Cite

Phase correction of skull aberration with 1.75-D and 2-D arrays using speckle targets

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2005 Wavefront distortion induced by the skull severely impacts transcranial ultrasound. In particular, the skull reduces the ability to monitor flow in the cerebral vasculature. We present B-scan and color flow images, aberratred with polymer casts of skull bo ... Full text Cite

Real-time 3D ultrasound laparoscopy

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2005 We have previously described 2D array ultrasound transducers operating up to 13.5 MHz for applications including real time 3D transthoracic imaging, real time volumetric intracardiac echocardiography (ICE), real time transesophageal echocardiography (TEE) ... Full text Cite

Finite-element analysis of temperature rise and lesion formation from catheter ultrasound ablation transducers.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · October 2005 A model using finite-element analysis (FEA) has been developed to calculate the temperature rise in tissue from intracardiac ultrasound ablation catheters and to predict if this temperature rise is adequate for producing a lesion in the tissue. In the mode ... Full text Cite

Real-time 3D laparoscopic ultrasonography.

Journal Article Ultrason Imaging · July 2005 We have previously described 2D array ultrasound transducers operating up to 10 MHz for applications including real time 3D transthoracic imaging, real time volumetric intracardiac echocardiography (ICE), real time 3D intravascular ultrasound (IVUS) imagin ... Full text Link to item Cite

Catheter ultrasound phased-array transducers for thermal ablation: a feasibility study.

Journal Article Ultrasonic imaging · April 2005 The feasibility of catheter single-element ultrasound transducers for cardiac ablation has been shown previously. We describe the design and testing of catheter-sized linear phased arrays transducers for ultrasound ablation. One array has 86 PZT-4 elements ... Full text Cite

Endoscopic optical coherence tomography imaging probe using a MEMS actuator

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · December 17, 2004 Endoscopic optical coherence tomography (EOCT) is a medical imaging technique that uses infrared light delivered via an endoscope to produce high-resolution images of tissue microstructure of the gastrointestinal tract. A key component of an EOCT system is ... Full text Cite

Real time 3D ultrasound imaging of the brain

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2004 We tested the feasibility of real time three dimensional ultrasound imaging in the brain with a 2.5MHz 2D array using a Volumetrics Model 1 scanner. In a human subject, the real time 3D scans produced simultaneous transcranial axial, coronal and saggital i ... Cite

Real-time 3D transesophageal echocardiography

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2004 Transesophageal echocardiography (TEE) is established as an essential diagnostic tool for patients that are obese or that exhibit signs of pulmonary disease. However, current techniques in transesophageal scanning of the heart are limited by the maneuverab ... Cite

Real-time 3D color doppler for guidance of vibrating interventional devices

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2004 The goal of this investigation is to examine the feasibility of guiding interventional devices using piezoelectric buzzers to create a velocity source, which is imaged and tracked with real time 3D (RT3D) ultrasound and Color Doppler. Interventional device ... Cite

Finite element analysis of temperature rise from an integrated 3-D intracardiac echo and ultrasound ablation transducer

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2004 A method for simulating the temperature rise due to acoustic heating from an ablation transducer is introduced. The size of lesions produced by this temperature rise is also modeled. First the intensity from the transducer is calculated using Field II. Thi ... Cite

Real-time 3D ultrasound with multiple transducer arrays

Journal Article Proceedings - IEEE Ultrasonics Symposium · December 1, 2004 Modifications were made to a commercial real time 3D ultrasound system for near simultaneous 3D scanning with two 2-D array transducers. As a first illustration, a transducer cable assembly was modified to incorporate two independent 3D intracardiac echo c ... Cite

Biomechanics of cranial dynamics during daily living activities

Journal Article Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings · December 1, 2004 Motion tracking capabilities of a head-mounted accelerometer apparatus were investigated in conjunction with three-dimensional motion analysis techniques during activities of daily living. In this report, measures between systems are compared for jogging, ... Cite

A miniaturized catheter 2-D array for real-time, 3-D intracardiac echocardiography.

Journal Article IEEE Trans Ultrason Ferroelectr Freq Control · October 2004 The design, fabrication, and characterization of a 112 channel, 5 MHz, two-dimensional (2-D) array transducer constructed on a six layer flexible polyimide interconnect circuit is described. The transducer was mounted in a 7 Fr (2.33 mm outside diameter) c ... Full text Link to item Cite

Feasibility study: real-time 3-D ultrasound imaging of the brain.

Journal Article Ultrasound Med Biol · October 2004 We tested the feasibility of real-time, 3-D ultrasound (US) imaging in the brain. The 3-D scanner uses a matrix phased-array transducer of 512 transmit channels and 256 receive channels operating at 2.5 MHz with a 15-mm diameter footprint. The real-time sy ... Full text Link to item Cite

Real-time 3D transesophageal echocardiography.

Journal Article Ultrason Imaging · October 2004 Transesophageal echocardiography (TEE) is an essential diagnostic tool in patients with poor transthoracic echocardiographic windows or when detailed imaging of structures distant from the chest wall is necessary. A real-time 3D TEE probe has been fabricat ... Full text Link to item Cite

Integrated catheter for 3-D intracardiac echocardiography and ultrasound ablation.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · July 2004 A catheter device with integrated ultrasound imaging array and ultrasound ablation transducer is introduced. This device has been designed for use in interventional cardiac procedures in which the cardiac anatomy is first imaged using real-time three-dimen ... Full text Cite

Real-time 3D color flow Doppler for guidance of vibrating interventional devices.

Journal Article Ultrason Imaging · July 2004 The goal of this investigation was to examine the feasibility of guiding interventional devices using piezoelectric buzzers to create velocity sources, which were imaged and tracked with real-time 3D color flow Doppler. The interventional devices examined ... Full text Link to item Cite

Two dimensional arrays for real time 3D intravascular ultrasound.

Journal Article Ultrasonic imaging · April 2004 We have previously described 2D arrays operating at up to 10.0 MHz consisting of several thousand elements for transthoracic cardiac imaging and over a hundred elements for intracardiac imaging using 7 Fr to 12 Fr catheters. We have begun to explore forwar ... Full text Cite

Real-time rectilinear 3-D ultrasound using receive mode multiplexing.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · February 2004 In previous work, we developed two generations of a real-time rectilinear volumetric scanner operating at 5 MHz for abdominal, breast, or vascular imaging using a Mills cross two-dimensional (2-D) array and a rectilinear periodic 2-D array. To improve spat ... Cite

Real-Time Rectilinear 3-D Ultrasound Using Receive Mode Multiplexing

Journal Article IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control · January 1, 2004 In previous work, we developed two generations of a real-time rectilinear volumetric scanner operating at 5 MHz for abdominal, breast, or vascular imaging using a Mills cross two-dimensional (2-D) array and a rectilinear periodic 2-D array. To improve spat ... Full text Cite

Advances in two dimensional arrays for real time 3D intravascular ultrasound

Journal Article Proceedings - IEEE Ultrasonics Symposium · January 1, 2004 Real time 3D IVUS may require imaging depths of a few centimeters to look down the axis of a coronary vessel to view vulnerable atherosclerotic plaque. We have previously described 2D array transducers for forward looking real time 3D intravascular ultraso ... Cite

Scanning mirror for optical coherence tomography using an electrostatic MEMS actuator

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · December 5, 2003 This paper describes a compact micromirror device for use in the scanning arm of an optical coherence tomography (OCT) system using an electrostatic micromachine (MEMS) actuator. Optical deflections of these MEMS mirror devices range from 18 degrees at low ... Full text Cite

Advances in 2-D array catheter transducers for real-time three-dimensional intracardiac echocardiography

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 2003 In this paper, we describe advances in the design, fabrication and testing of two-dimensional catheter-mounted arrays for real-time three-dimensional (RT3-D) intracardiac echocardiography (ICE). These include a 7 Fr (2.3 mm O.D.), 112 element 2-D array uti ... Cite

Integrated catheter for 3-D intracardiac echocardiography and ultrasound ablation

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 2003 We present an integrated catheter for 3-D intracardiac echocardiography and ultrasound ablation. The device uses a 9 Fr (3 mm O.D.) catheter lumen with a 14 Fr (4.7 mm O.D.) tip. Real-time 3D imaging is achieved with a forward-looking 112 element, 5 MHz tw ... Cite

Integrated catheter for 3-D intracardiac echocardiography and ultrasound ablation

Real-time rectilinear 3-D ultrasound with 4:1 receive mode multiplexing

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 2003 In previous work, we developed two generations of a real-time rectilinear volumetric scanner operating at 5 MHz for abdominal, breast or vascular imaging using a Mills cross 2-D array and a rectilinear periodic 2-D array. To improve spatial resolution perf ... Cite

Two dimensional arrays for real time 3D intravascular ultrasound

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 2003 We have previously described 2D arrays operating at up to 10.0 MHz consisting of several thousand elements for transthoracic cardiac imaging and over a hundred elements for intracardiac imaging using 7 Fr to 12 Fr catheters. Other laboratories have propose ... Cite

Real-time rectilinear 3-D ultrasound with 4:1 receive mode multiplexing

Real-time cylindrical curvilinear 3-D ultrasound imaging

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 2003 In patients that are obese or that exhibit signs of pulmonary disease, standard transthoracic scanning may yield poor quality cardiac images. For these conditions, two-dimensional transesophageal echocardiography (TEE) is established as an essential diagno ... Cite

Combined 3D intracardiac echo and ultrasound ablation

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · September 12, 2003 We have integrated real time volumetric ultrasound imaging and ultrasound ablation in the same intracardiac catheter. This single device could be used to visualize ablation sites in three dimensions immediately prior to inducing necrosis to eliminate cardi ... Full text Cite

Dual lumen transducer probes for real-time 3-D interventional cardiac ultrasound.

Journal Article Ultrasound Med Biol · September 2003 We have developed dual lumen probes incorporating a forward-viewing matrix array transducer with an integrated working lumen for delivery of tools in real-time 3-D (RT3-D) interventional echocardiography. The probes are of 14 Fr and 22 Fr sizes, with 112 c ... Full text Link to item Cite

Real-time cylindrical curvilinear 3-D ultrasound imaging.

Journal Article Ultrasonic imaging · July 2003 In patients who are obese or exhibit signs of pulmonary disease, standard transthoracic scanning may yield poor quality cardiac images. For these conditions, two-dimensional transesophageal echocardiography (TEE) is established as an essential diagnostic t ... Full text Cite

Electrostatic micromachine scanning mirror for optical coherence tomography.

Journal Article Optics letters · April 2003 Compact electrostatic micromirror structures for use in the scanning arm of an optical coherence tomography (OCT) system are described. These devices consist of millimeter-scale mirrors resting upon micrometer-scale polyimide hinges that are tilted by a li ... Full text Cite

Ultrasound: Transducers

Chapter · January 1, 2003 An ultrasound transducer generates acoustic waves by converting magnetic, thermal, and electrical energy into mechanical energy. The most efficient technique for medical ultrasound uses the piezoelectric effect, which was first demonstrated in 1880 by Jacq ... Cite

Two dimensional arrays for 3-D ultrasound imaging

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 2002 Phased array ultrasound transducers have been fabricated in our laboratories at Duke University since 1970. In 1986, we began the development of 2-D arrays with a 20 × 20 element Mills cross array including 64 active channels operating at 1 MHz which produ ... Cite

Optical scanner using a MEMS actuator

Journal Article Sensors and Actuators, A: Physical · December 1, 2002 Optical scanners have numerous applications from bar code readers and laser printers in industry to corneal resurfacing and optical coherence tomography in medicine. We have developed an optical scanner fabricated using photolithography on a polyimide subs ... Full text Cite

A micromachine high frequency ultrasound scanner using photolithographic fabrication.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · July 2002 In this paper we describe two new types of transducer assemblies fabricated from polyimide films with photolithography that use a polyimide micromachine (MEMS) actuator to mechanically scan an ultrasound beam. Forward viewing transducers pivoting on cantil ... Full text Cite

Real-time rectilinear volumetric imaging using a periodic array.

Journal Article Ultrasound in medicine & biology · July 2002 Current real-time phased array volumetric scanners use a 2-D array to scan a pyramidal volume comprised of many sector scans stacked in the elevation direction. This scan format is primarily useful for cardiac imaging to avoid interference from the ribs. H ... Full text Cite

Finite element comparison of single crystal vs. multi-layer composite arrays for medical ultrasound.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · July 2002 Finite element (PZFlex; Weidlinger Assoc., New York, NY and Los Altos, CA) simulations predict that for a 2-MHz phased array element with a single matching layer, the three-layer hybrid structure [1] increases the pulse echo signal-to-noise ratio (SNR) by ... Full text Cite

Multi-layered PZT/polymer composites to increase signal-to-noise ratio and resolution for medical ultrasound transducers part II: thick film technology.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · July 2002 Increasing transducer bandwidth and signal-to-noise ratio (SNR) is fundamental to improving the quality of medical ultrasound images. In previous work, we have proposed the use of multi-layer 1-3 PZT/polymer composites to increase both, but have encountere ... Full text Cite

Intracardiac catheter 2-D arrays on a silicon substrate.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · April 2002 The design, fabrication, and characterization of a 7 MHz, two-dimensional (2-D) array transducer built on a silicon substrate is described. The array fits inside a 9-French (2.9 mm O.D.) catheter for use in real-time intracardiac volumetric imaging. The -6 ... Full text Cite

Guidance of cardiac pacemaker leads using real time 3D ultrasound: feasibility studies.

Journal Article Ultrasonic imaging · April 2002 We investigated the feasibility of the guidance of pacemaker lead implantation using the pacemaker lead stylet as an acoustic wave-guide combined with real time 3D ultrasound imaging. In one approach, with a 2.5 MHz transducer coupled to a stylet of a pace ... Full text Cite

Feasibility study of real-time three-dimensional intracardiac echocardiography for guidance of interventional electrophysiology.

Journal Article Pacing Clin Electrophysiol · March 2002 The authors tested the feasibility of real-time three-dimensional intracardiac echocardiography for guidance of interventional electrophysiological studies. The three-dimensional scanner uses a matrix array ultrasound transducer of 64 channels operating at ... Full text Link to item Cite

Real-time rectilinear volumetric imaging.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · January 2002 Current real-time volumetric scanners use a 2-D array to scan a pyramidal volume consisting of many sector scans stacked in the elevation direction. This scan format is primarily useful for cardiac imaging to avoid interference from the ribs. However, a re ... Full text Cite

Feasibility study for real time three dimensional Doppler intracardiac echocardiography.

Journal Article Ultrason Imaging · January 2002 Using catheter-mounted two-dimensional array transducers, we have obtained real-time three-dimensional color flow and spectral Doppler ultrasound images in phantoms. We have constructed several transducers operating at 5 MHz with up to 137 channels inside ... Full text Link to item Cite

A novel flex circuit area-array interconnect system for a catheter-based ultrasound transducer

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2002 Flexible circuitry is uniquely suited as an interconnect media for medical sensor area-array interconnection due to fine trace patterning capability, microvia technology and multilayer construction techniques. This paper describes a novel high density area ... Cite

Scanning mirror for optical coherence tomography using an electrostatic MEMS actuator

Conference Proceedings - International Symposium on Biomedical Imaging · January 1, 2002 This paper describes the development of a new type of optical coherence tomography (OCT) probe using an electrostatic micromachine (MEMS) actuator. These devices consist of millimeter scale mirrors resting on micron scale polyimide hinges that are tilted u ... Full text Cite

Real-time three dimensional intracardiac echocardiography for guidance of cardiac interventional procedures

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 2001 We have tested the feasibility of real-time three dimensional intracardiac echocardiography for guidance of interventional electrophysiology studies. We have constructed 2D array ultrasound transducers operating at 5MHz with 64 channels in a 12 F catheter, ... Cite

Real-time curvilinear and improved rectilinear volumetric imaging

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 2001 Current real time volumetric scanners use a two-dimensional array to scan a pyramidal volume comprised of many sector scans stacked in the elevation direction. This scan format is primarily useful for cardiac imaging to avoid interference from the ribs. Ho ... Cite

Real-time three-dimensional intracardiac echocardiography.

Journal Article Ultrasound Med Biol · September 2001 Using catheter-mounted 2-D array transducers, we have obtained real-time 3-D intracardiac ultrasound (US) images. We have constructed several transducers with 64 channels inside a 12 French catheter lumen operating at 5 MHz. The transducer configuration ma ... Full text Link to item Cite

High aspect ratio integrated force arrays

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · August 16, 2001 The Integrated Force Array (IFA) is a metallized polyimide actuator made up of a large array of capacitive cells that deform when voltage is applied. The deformations of the individual cells add to produce an overall muscle-like compression of the array. I ... Full text Cite

Synthetic muscle actuators: Applications in ultrasonic imaging and optical beam steering

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2001 There is much interest in the biomedical community in mechanically steering both high frequency ultrasound transducers and various optical beams. We are currently investigating the use of two different types of MEMS actuators, integrated force arrays (IFAs ... Full text Cite

Two dimensional arrays for real time volumetric and intracardiac imaging with simultaneous electrocardiogram

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 2000 Design, fabrication and performance of a two-dimensional array operating at 10 MHz for real time volumetric and intracardiac imaging with simultaneous electrocardiagram was presented. Use of the device to monitor and quantify RF ablation study was demonstr ... Cite

Micromachine intracardiac ultrasound scanner fabricated with integrated circuit technology

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 2000 We have previously described a hand crafted prototype intracardiac scanner that consists of a single high frequency PZT piston transducer that is mechanically steered by a micromachine (MEMS) actuator to produce a sector scan. More recently, we have improv ... Cite

Thick film sol gel PZT transducer using dip coating

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 2000 A sol gel process has been used to develop a 30 μm thick PZT coating on a sapphire wafer. The sol gel film was removed and plated with platinum electrodes. The free-standing film had a free dielectric constant (εT) of 820, a thickness-mode coupling coeffic ... Cite

Multi-layer composite hybrid transducer for medical ultrasound

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 2000 Increasing transducer bandwidth and signal-to-noise ratio (SNR) is fundamental to improving the quality of medical ultrasound images. In previous work, we have proposed the use of multi-layer 1-3 PZT/polymer composites to increase both, but have encountere ... Cite

Real time rectilinear volumetric imaging

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 2000 The current Duke real time volumetric scanner uses 40×40 arrays to scan a pyramidal volume comprised of 64 sector scans in the elevation direction. This scan format is primarily useful for cardiac imaging to avoid interference from the ribs. However, a rea ... Cite

Spiral Wound Transducer

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · December 1, 2000 The Spiral Wound Transducer (SWT) is a muscle-like actuator comprising an array of deformable capacitors. The SWT is fabricated as a flat multilayer metallized plastic structure on a silicon wafer. Conventional microelectronic manufacturing techniques are ... Full text Cite

Sparse 2-D array design for real time rectilinear volumetric imaging.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · January 2000 Several sparse 2-D arrays for real time rectilinear volumetric imaging were investigated. All arrays consisted of 128x128=16,384 elements with lambda spacing operating at 5 MHz. Because of system limitations, not all of the elements could be used. From eac ... Full text Cite

Intracardiac ultrasound scanner using a micromachine (MEMS) actuator.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · January 2000 Catheter-based intracardiac ultrasound offers the potential for improved guidance of interventional cardiac procedures. The objective of this research is the development of catheter-based mechanical sector scanners incorporating high frequency ultrasound t ... Full text Cite

Two dimensional arrays for real time intracardiac volumetric imaging

Journal Article Ultrasound in Medicine and Biology · January 1, 2000 We describe the design, fabrication, and evaluation of catheter mounted two dimensional array transducers for real time intracardiac volumetric scanning as a guide for cardiac interventional procedures including electrophysiological mapping and radiofreque ... Cite

Two dimensional arrays for real time intracardiac volumetric imaging

Journal Article Ultrasound in Medicine and Biology · 2000 We describe the design, fabrication, and evaluation of catheter mounted two dimensional array transducers for real time intracardiac volumetric scanning as a guide for cardiac interventional procedures including electrophysiological mapping and radiofreque ... Cite

High-density flexible interconnect for two-dimensional ultrasound arrays.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · January 2000 We present a method for fabricating flexible multilayer circuits for interconnection to 2-D array ultrasound transducers. In addition, we describe four 2-D arrays in which such flexible interconnect is implemented, including transthoracic arrays with 438 c ... Full text Cite

Two dimensional arrays for real time intracardiac volumetric imaging

Scalable synthetic muscle actuator

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2000 We will discuss our work to build, characterize, and scale-up a metallized plastic muscle-like actuator called a Spiral Wound Transducer (SWT). Prototype SWTs have been built using microelectronics fabrication methods. The prototypes have demonstrated larg ... Cite

Microelectromechanical actuator with extended range and enhanced force: fabrication, test, and application as a mechanical scanner

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · December 1, 1999 A miniature ultrasound scanner has been constructed using a MEMS actuator called an Integrated Force Array (IFA). A second type of actuator called a Spiral Wound Transducer (SWT) is under development and shows significant promise for this application. Both ... Cite

Update of two dimensional arrays for real time volumetric and real time intracardiac imaging

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1999 We have previously described 2-D array transducers with up to several thousand elements operating at frequencies between 2.5 and 5.0 MHz for real time volumetric imaging. Lately, there has been interest in developing catheter based intracardiac imaging sys ... Cite

Finite element analysis of multi-layer composite hybrid and single crystal medical ultrasound transducers

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1999 Increasing transducer bandwidth and signal-to-noise ratio (SNR) is fundamental to improving the quality of medical ultrasound images. In previous work, we have proposed the use of multi-layer 1-3 PZT/polymer composites to increase both, but have encountere ... Cite

Intracardiac ultrasound catheter using a micromachine (MEMS) actuator

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1999 Catheter based intracardiac ultrasound offers the potential for improved guidance of interventional cardiac procedures. The objective of this work is the development of catheter based, forward-looking mechanical sector scanners incorporating high frequency ... Cite

Two-dimensional catheter arrays for real time intracardiac volumetric imaging

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · January 1, 1999 The arrays for intracardiac volumetric imaging based upon two different designs: a 10×10 = 100 element 5 MHz forward looking 2-D array; and a 13×11 = 143 element 5 MHz 2-D array for side scanning are constructed. For the forward looking 2-D arrays, the tra ... Cite

Ultrasonic imaging using a 5-MHz multilayer/single-layer hybrid array for increased signal-to-noise ratio.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · January 1999 Conventional diagnostic ultrasound scanners are bulky and require significant amounts of electrical power during operation. Reducing the size, weight, and consumption of electrical power is made easier through the use of highly integrated compact transmit ... Full text Cite

Multi-layered PZT/polymer composites to increase signal-to-noise ratio and resolution for medical ultrasound transducers.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · January 1999 Increasing transducer bandwidth and signal-to-noise ratio (SNR) is fundamental to improving the quality of medical ultrasound images. In previous work, the authors have proposed the use of multi-layer 1-3 PZT/epoxy composites to increase both but have enco ... Full text Cite

Finite element analysis of a deformable array transducer.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · January 1999 Deformable array transducers have previously been described to implement 2-D phase aberration correction of near-field aberrators with only a 1xN or 2xN array configuration. This transducer design combines mechanical phase correction using an actuator with ... Full text Cite

Multi-layered PZT/polymer composites to increase signal to noise ratio and resolution for medical ultrasound transducers

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1998 Increasing transducer bandwidth and signal to noise ratio (SNR) is fundamental in improving the quality of medical ultrasound images. A multilayer PZT/polymer composite hybrid array that will not require post alignment is developed. This structure consists ... Full text Cite

Ultrasonic imaging using optoelectronic transmitters.

Journal Article Ultrasonic imaging · April 1998 Conventional ultrasound scanners utilize electronic transmitters and receivers at the scanner with a separate coaxial cable connected to each transducer element in the handle. The number of transducer elements determines the size and weight of the transduc ... Full text Cite

Progress in two-dimensional arrays for real-time volumetric imaging.

Journal Article Ultrasonic imaging · January 1998 The design, fabrication, and evaluation of two dimensional array transducers for real-time volumetric imaging are described. The transducers we have previously described operated at frequencies below 3 MHz and were unwieldy to the operator because of the i ... Full text Cite

Two-dimensional arrays for medical ultrasound using multilayer flexible circuit interconnection.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · January 1998 The development of 2-D array transducers has received much recent interest. Unfortunately, fabrication of high density 2-D arrays is difficult due to the large number of electrical interconnections which must be made to the back side of the elements. A typ ... Full text Cite

Phase aberration correction in two dimensions with an integrated deformable actuator/transducer

Journal Article IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control · December 1, 1997 Two-dimensional arrays are required to implement two-dimensional phase aberration correction using traditional electronic correction techniques. A new transducer design, deformable in the elevation dimension, can be used to implement two-dimensional phase ... Full text Cite

Modeling of piezoelectric multilayer ceramics using finite element analysis

Journal Article IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control · December 1, 1997 For medical ultrasound imaging, 2-D array transducers have greater versatility than linear arrays. Unfortunately, the tiny array elements in a 2-D array have poor signal-to-noise ratio (SNR). We have previously shown that SNR is increased in 2-D array tran ... Full text Cite

Experimental results from an electrostrictive multiplexed 2-D array

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1997 A 2:1 multiplexed two-dimensional array has been developed which has a sparse element pattern designed for real time volumetric imaging and a second element pattern designed for conventional B-mode imaging. For volumetric imaging a small aperture was used ... Cite

Ultrasonic imaging using optoelectronic transmitters

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1997 Conventional ultrasound scanners utilize electronic transmitters and receivers at the scanner with a separate coaxial cable connected to each transducer element in the handle. 2-D arrays which allow new imaging modalities to be introduced significantly inc ... Cite

Finite element analysis of a deformable array transducer

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1997 Deformable array transducers have previously been described to implement 2-D phase aberration correction of near-field aberrators with only a 1×N or 2×N array configuration. This transducer design combines mechanical phase correction using an actuator with ... Cite

Advances in two dimensional arrays for real time volumetric imaging

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1997 We have previously described prototype two-dimensional arrays used for real time volumetric imaging. However, these arrays primarily operated at frequencies below 3.0 MHz, have been unwieldy to the operator due to the interconnect schemes used, and have ta ... Cite

A two-dimensional array for B-mode and volumetric imaging with multiplexed electrostrictive elements.

Journal Article Ultrasonic imaging · October 1997 A 2:1 multiplexed 2-D array has been developed that has a sparse element pattern designed for real time volumetric imaging and an alternate element pattern designed for B-mode imaging. For volumetric imaging, a small aperture was used to provide a wide tra ... Full text Cite

Improved signal-to-noise ratio in hybrid 2-D arrays: experimental confirmation.

Journal Article Ultrasonic imaging · April 1997 2-D array transducers have shown significant promise for medical ultrasound over conventional linear arrays, at the cost of increasing the number of channels, difficulty of fabrication and array element impedance. The increase in element impedance reduces ... Full text Cite

Hybrid multi/single layer array transducers for increased signal-to-noise ratio.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · January 1997 In medical ultrasound imaging, two-dimensional (2-D) array transducers are necessary to implement dynamic focusing in two dimensions, phase correction in two dimensions and high speed volumetric imaging. However, the small size of a 2-D array element resul ... Full text Cite

Integrated force array: interface to external systems

Journal Article Proc. SPIE - Int. Soc. Opt. Eng. (USA) · 1997 Integrated Force Arrays (IFAs) are thin film linear actuators which operate with substantial displacement and force. The methods of attachment of these devices to external systems are under development. Our current methods to incorporate IFAs in an scannin ... Cite

Signal to noise ratio of hybrid multilayer/single layer 2-D arrays

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1996 In our previous work, we examined the improved transmit sensitivity of 2-D array transducers using multilayer PZT. In receive mode, the signal to noise ratio (SNR) requires a more complex examination. Typically, a coaxial cable connects a single layer elem ... Cite

Multiplexed two-dimensional array for real time volumetric and B-mode imaging

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1996 The Duke University real time volumetric imaging system employs receive mode parallel processing to increase image frame rate. This technique has an associated reduction in image resolution and contrast due to the requirement of a wide transmit beam. Since ... Cite

Combining multi-layers and composites to increase SNR for medical ultrasound transducers

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1996 Current 1.5-D and 2-D array elements suffer low capacitance resulting in high electrical impedance. The impedance mismatch between the 50Ω transmitter source impedance and the high impedance array elements decreases efficiency. Multi-layer PZT designs usin ... Cite

2-D array transducers for medical ultrasound at Duke University: 1996

Journal Article IEEE International Symposium on Applications of Ferroelectrics · December 1, 1996 Two dimensional array transducers for medical ultrasound applications using multilayer ceramic (MLC) connectors were fabricated using microelectronic techniques was developed with inter-laminar vias combined with a λ/4 acoustic mismatching layer. A random ... Cite

Phase aberration correction in two dimensions with an integrated deformable actuator/transducer

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1996 Two-dimensional arrays are required to implement two-dimensional phase correction using traditional electronic correction techniques. A new transducer design, deformable in the elevation dimension, can be used to implement two-dimensional phase correction ... Cite

Integrated force array: positioning drive applications

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · January 1, 1996 Integrated Force Arrays (IFAs) are thin film membrane actuators that act as transfer devices for electrostatic force. They are capable of large amplitude motion and evidence significant energies per unit volume (eg. 8.2 erg/mm 3). Devices which use IFAs as ... Cite

Phase aberration correction in two dimensions using a deformable array transducer

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1995 Two-dimensional arrays are required to implement an electronic two-dimensional phase correction in tissue. Instead of using a two-dimensional array, a new technique is proposed which uses a deformable transducer of significantly fewer channels for two-dime ... Cite

Update on 2-D array transducers for medical ultrasound

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1995 Since 1986, several attempts have been made to develop prototype 1 1/2 -D and 2-D transducer arrays. Early efforts have not been successful enough because there are some factors that limit the development of such transducer arrays. These include the requir ... Cite

Relaxor ferroelectric materials in two-dimensional transducer arrays

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1995 Relaxor ferroelectric materials are characterized by high dielectric permitivities and bias controllable piezoelectric response, making them attractive for ultrasonic imaging applications. We propose using relaxor ferroelectrics to multiplex a 2-D array fo ... Cite

Phase aberration correction in two dimensions using a deformable array transducer.

Journal Article Ultrasonic imaging · July 1995 Phase aberrations due to tissue inhomogeneities degrade medical ultrasound images by disrupting the ultrasound beam focus. Currently, phase correction algorithms are implemented by adjusting the electronic phase delays uses to steer and focus the ultrasoun ... Full text Cite

Optimization of signal-to-noise ratio for multilayer PZT transducers.

Journal Article Ultrasonic imaging · April 1995 In medical ultrasound imaging, two-dimensional (2-D) array transducers are desirable to implement dynamic focusing and phase aberration correction in two dimensions as well as volumetric imaging. Unfortunately, the small size of a 2-D array element results ... Full text Cite

Optoelectronic Transmitters for Medical Ultrasound Transducers

Journal Article IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control · January 1, 1995 Optoelectronics and fiber optics can be used to miniaturize and improve the flexibility of the transducer cable and transducer handle of medical diagnostic ultrasound scanners. The reduction in size has gained importance as 2-D array transducers with up to ... Full text Cite

Cardiac ultrasound phantom using a porcine heart model.

Journal Article Ultrasound in medicine & biology · January 1995 A beating cardiac phantom has been developed using an excised porcine heart for use as a training tool in echocardiography. The heart is fixed with a formalin-based preservation method, housed in an optically transparent Lexan chamber, and undergoes hydrau ... Full text Cite

Optoelectronic transmitters for medical ultrasound transducers

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1994 Optoelectronics and fiber optics can be used to miniaturize and improve the flexibility of the transducer cable and handle of medical diagnostic ultrasound scanners. The reduction in size will gain importance as 2-D array transducers with up to 1000 indepe ... Cite

Multilayer 2-D array transducers with integrated circuit transmitters and receivers: a feasibility study

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1994 In 2-D arrays, the elements have poor signal-to-noise ratio (SNR) because their small size results in a small clamped capacitance and a large electrical impedance near resonance. The SNR can be increased using multi-layer PZT transducers. It is hypothesize ... Cite

Improved cardiac anthropomorphic phantom.

Journal Article J Ultrasound Med · August 1994 An improved cardiac sonographic phantom is described that simulates the anatomy of the human heart for applications as a low cost quality assurance and training tool in echocardiography. The major new feature in the phantom is the development of a polyuret ... Full text Link to item Cite

Two-dimensional random arrays for real time volumetric imaging.

Journal Article Ultrasonic imaging · July 1994 Two-dimensional arrays are necessary for a variety of ultrasonic imaging techniques, including elevation focusing, 2-D phase aberration correction, and real time volumetric imaging. In order to reduce system cost and complexity, sparse 2-D arrays have been ... Full text Cite

Multilayer piezoelectric ceramics for two-dimensional array transducers.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · January 1994 In medical ultrasound imaging, 2-D array transducers have become essential to implement dynamic focusing and phase-correction in the elevation dimension as well as real-time volumetric scanning. Unfortunately, the small size of a 2-D array element results ... Full text Cite

Sparse geometries for two-dimensional array transducers in volumetric imaging

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1993 In this paper two random sparse array geometries and an ad hoc sparse array were simulated and compared to a fully sampled aperture with the same overall dimensions. The sparse arrays were designed to the constraints of the Duke University real time volume ... Cite

Performance of multi-layer 2-D transducer arrays

Journal Article Proceedings of the IEEE Ultrasonics Symposium · December 1, 1993 In medical ultrasound imaging, 2-D array transducers have become essential to implement dynamic focusing and phase-correction in the elevation dimension as well as real-time volumetric scanning. Unfortunately, 2-D array elements have poor sensitivity becau ... Cite

Two-dimensional array transducers using thick film connection technology.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · January 1993 A connection technique for two-dimensional array ultrasound transducers developed by combining a conductive lambda/4 mismatching layer with a multi-layer ceramic (MLC) connector using thick-film microelectronic technology is described. The connector consis ... Full text Cite

Performance of multi-layer PZT transducer arrays

Journal Article Proceedings of the Ultrasonics International Conference · January 1, 1993 Two-dimensional arrays are critical to the future of medical ultrasound for focusing and phase correction in the elevation dimension and for 3-D scanning. Poor sensitivity is a serious problem with such 2-D arrays because their small element size results i ... Full text Cite

Two dimensional ultrasonic beam distortion in the breast: in vivo measurements and effects.

Journal Article Ultrason Imaging · October 1992 Two dimensional arrival time data was obtained for the propagation of ultrasound across the breasts of 7 female volunteers. These profiles were extracted through the use of cross-correlation measurements and a simulated annealing process that maintained ph ... Full text Link to item Cite

Two-dimensional arrays for medical ultrasound.

Journal Article Ultrasonic imaging · July 1992 The design, fabrication and evaluation of two-dimensional transducer arrays are described for medical ultrasound imaging. A 4 x 32, 2.8 MHz array was developed to use new signal processing techniques for improved B-scan imaging including elevation focusing ... Full text Cite

In vivo imaging using a copolymer phased array.

Journal Article Ultrasonic imaging · July 1992 Phased-array images have been obtained in vivo with a steered copolymer array operating at 2.5 MHz. The array was fabricated using 28 microns copolymer film, lambda/4 resonant at 21 MHz, which was bonded to a glass ceramic backing with a thin film bond. Th ... Full text Cite

Multi-layer PZT transducer arrays for improved sensitivity

Conference Proceedings - IEEE Ultrasonics Symposium · January 1, 1992 Two-dimensional arrays are critical to the future of medical ultrasound for focusing and phase correction in the elevation dimension and for 3-D scanning. Poor sensitivity is a serious problem with such 2-D arrays because their small element size results i ... Full text Cite

Two-dimensional array transducers using hybrid connection technology

Conference Proceedings - IEEE Ultrasonics Symposium · January 1, 1992 We previously described 2-D array transducers consisting of 16 x 16 = 256 PZT-5H elements operating at 2.5 MHz fabricated by hand wiring. Element spacing is 0.5 mm x 0.5 mm. There are severe difficulties in electrical connnection to such elements which are ... Full text Cite

Anthropomorphic cardiac ultrasound phantom with coronary arteries

Journal Article Proceedings of the Annual Conference on Engineering in Medicine and Biology · December 1, 1991 The cardiac anthropomorphic ultrasound phantom is improved by the addition of two new features. An aorta with a bifurcation is molded into the torso via a 'lost wax' procedure. B-scan images of contrast medium and color-flow Doppler images show flow patter ... Cite

High-speed ultrasound volumetric imaging system. II. Parallel processing and image display.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · January 1991 For pt.I see ibid., vol.38, no.2, p.100-8 (1991). The authors describe the design, application, and evaluation of parallel processing to the high-speed volumetric ultrasound imaging system. The scanner produces images analogous to an optical camera or the ... Full text Cite

High-speed ultrasound volumetric imaging system. I. Transducer design and beam steering.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · January 1991 Transducer design and phased array beam steering are developed for a volumetric ultrasound scanner that enables the 3-D visualization of dynamic structures in real time. The authors describe the design considerations and preliminary evaluation of a high-sp ... Full text Cite

Improved real time volumetric ultrasonic imaging system

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · January 1, 1991 A real time volumetric ultrasonic imaging system has been improved through the use of parallel processing in two dimensions. The imaging system uses pulse-echo phased array principles to steer a two-dimensional transducer array in a pyramidal scan format. ... Cite

Real-time, three-dimensional echocardiography: feasibility and initial use.

Journal Article Echocardiography · January 1991 The purpose of this article is to review new approaches to three-dimensional acquisition and presentation of echocardiographic data. New three-dimensional phased-array devices hold great promise for the development and application of new descriptors for le ... Full text Link to item Cite

Two-dimensional arrays for medical ultrasound

Conference Proceedings - IEEE Ultrasonics Symposium · January 1, 1991 The design, fabrication and evaluation of twodimensional transducer arrays are described for medical ultrasound imaging. A 4 x 32, 2.8 MHz array was developed to use new signal processing techniques for improved B-scan imaging including elevation focusing, ... Full text Cite

Real time volumetric ultrasound imaging system.

Journal Article Journal of digital imaging · November 1990 A real time volumetric ultrasound imaging system has been developed for medical diagnosis. The scanner produces images analogous to an optical camera and supplies more information than conventional sonograms. Potential medical applications include improved ... Full text Cite

Real time volumetric ultrasound imaging system

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · July 1, 1990 A real time volumetric ultrasound imaging system has been developed for medical diagnosis. The scanner produces images analogous to an optical camera or the human eye and supplies more information than conventional sonograms. Potential medical applications ... Full text Cite

Experimental results with a real-time adaptive ultrasonic imaging system for viewing through distorting media.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · January 1990 An online adaptive phased-array ultrasonic imaging system capable of markedly improving the detectability of targets viewed through inhomogeneous media is described. An online adaptive phase correction technique implemented on a research phased-array scann ... Full text Cite

System for real-time, adaptive ultrasonic imaging

Journal Article Ultrasonics Symposium Proceedings · December 1, 1989 A real-time adaptive ultrasonic imaging system capable of markedly and quickly improving the quality of images degraded by aberrating media is described. The system employs one of several possible functions of regional image brightness as a quality factor. ... Cite

Anthropomorphic cardiac ultrasound phantom

Journal Article Ultrasonics Symposium Proceedings · December 1, 1989 A phantom is described which simulates the human cardiac anatomy for applications in ultrasound imaging, ultrasound Doppler, and color-flow Doppler imaging. The phantom consists of a polymer left ventricle with prosthetic mitral and aortic valves which is ... Cite

Laboratory evaluation of the Maltese cross processor: Speckle reduction for circular transducers

Journal Article Ultrasonics Symposium Proceedings · December 1, 1989 An online signal-processing technique to reduce speckle noise in ultrasound images is described. In the imaging system, a focused piston transducer is divided into 32 sectors. In the receive mode, parallel signal processing arranges the sectors into eight ... Cite

Anthropomorphic cardiac ultrasound phantom.

Journal Article IEEE transactions on bio-medical engineering · October 1989 A new phantom is described which simulates the human cardiac anatomy for applications in ultrasound imaging, ultrasound Doppler, and color-flow Doppler imaging. The phantom consists of a polymer left ventricle which includes a prosthetic mitral and aortic ... Full text Cite

Phase aberration correction in medical ultrasound using speckle brightness as a quality factor.

Journal Article The Journal of the Acoustical Society of America · May 1989 Medical ultrasonic images are degraded by tissues with inhomogeneous acoustic velocities. The resulting phase aberration raises the off-peak response of the imaging system's point spread function (PSF), decreasing dynamic range. In extreme cases, multiple ... Full text Cite

New contrast-detail phantoms for improved precision in lesion detection measurements.

Journal Article Ultrasound in medicine & biology · January 1989 The previous design of our ultrasound contrast-detail (C-D) phantom is limited in its ability to evaluate the quality of diagnostic ultrasound imaging systems. There is uncertainty in the contrast-detail measurements due to the single available viewing ang ... Full text Cite

In vitro ultrasonic imaging of flow patterns in a left ventricular assist device

Journal Article IEEE/Engineering in Medicine and Biology Society Annual Conference · November 1, 1988 Diagnostic ultrasound imaging systems are used without Doppler to visualize, in vitro, the flow patterns within a blood sac from a pneumatic left ventricular assist device (LVAD). The circulatory system of the LVAD uses aerated tap water, which also serves ... Cite

The Maltese cross processor: speckle reduction for circular transducers.

Journal Article Ultrasonic imaging · July 1988 A new online signal processing technique is described to reduce speckle noise in ultrasound images. In the imaging system, a focused piston transducer is divided into thirty-two sectors. In the receive mode, parallel signal processing arranges the sectors ... Full text Cite

Properties of acoustical speckle in the presence of phase aberration. Part II: Correlation lengths.

Journal Article Ultrasonic imaging · January 1988 In recent years, analysis of the second order statistics of ultrasound speckle has led to accurate prediction and measurements of the average speckle size in the transducer focal zone. In this paper, that work has been extended to the average speckle size ... Full text Cite

Properties of acoustical speckle in the presence of phase aberration. Part I: First order statistics.

Journal Article Ultrasonic imaging · January 1988 The first order statistical properties of acoustical speckle patterns are studied as a function of several types of random and structured phase error. Such errors may arise from tissue velocity inhomogeneities or limitations in the acoustical imaging syste ... Full text Cite

Fundamental Correlation Lengths of Coherent Speckle in Medical Ultrasonic Images

Journal Article IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control · January 1, 1988 Refinements to previous analyses of the natural correlation lengths within simple images and between images to be compounded are presented. Comparison of theoretical and experimental results show very good agreement for the case of Rayleigh scattering medi ... Full text Cite

Speckle reduction achievable by spatial compounding and frequency compounding: Experimental results and implications for target detectability

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · September 10, 1987 The degree of speckle reduction achievable by spatial and frequency compounding is a function of the rates of speckle pattern change induced by varying the imaging system’s illumination angle and acoustic frequency, respectively. We have measured these rat ... Full text Cite

Statistical physics of medical ultrasonic images

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · September 10, 1987 The physical and statistical properties of backscattered signals in medical ultrasonic imaging are reviewed in terms of: 1) the radiofrequency signal; 2) the envelope (video or magnitude) signal; and 3) the density of samples in simple and in compounded im ... Full text Cite

In vitro ultrasonic imaging of flow through prosthetic heart valves.

Journal Article Medical instrumentation · April 1987 A rapid, inexpensive, portable technique has been developed for the qualitative and semiquantitative evaluation of in vitro flow characteristics through prosthetic heart valves. The technique combines a cardiac pulse duplicator and any diagnostic, linear s ... Cite

SPECKLE SNR VS. LATERAL RESOLUTION IN ULTRASOUND IMAGING: WHAT'S THE TRADEOFF?

Journal Article Ultrasonics Symposium Proceedings · December 1, 1986 The rates of ultrasonic B-mode speckle pattern changes are measured as a function of changes in the imaging angle under a variety of experimental conditions. The results of these experiments were used to design an imaging system that optimizes speckle redu ... Cite

A quantitative approach to speckle reduction via frequency compounding.

Journal Article Ultrasonic imaging · July 1986 Coherent speckle is a source of image noise in ultrasonic B-mode imaging. The use of multiple imaging frequencies has been suggested as a technique for speckle contrast reduction. This technique involves the averaging of images whose speckle patterns have ... Full text Cite

Phased array ultrasound imaging through planar tissue layers.

Journal Article Ultrasound in medicine & biology · March 1986 Conventional ultrasound imaging devices are designed based on the assumption of a homogeneous tissue medium of constant acoustic velocity = 1540 m/sec. However, the body consists of tissue layers of varying thicknesses and velocities which range from 1470 ... Full text Cite

Speckle reduction in medical ultrasound via spatial compounding

Journal Article Proc. SPIE - Int. Soc. Opt. Eng. (USA) · 1986 In order to design improved spatial compounding ultrasound scanning systems it is necessary to determine the correlation of speckle patterns as a function of aperture translation. The authors have conducted experiments measuring the speckle correlation as ... Cite

SPECKLE PATTERN CHANGES WITH VARYING ACOUSTIC FREQUENCY: EXPERIMENTAL MEASUREMENT AND IMPLICATIONS FOR FREQUENCY COMPOUNDING.

Journal Article Ultrasonics Symposium Proceedings · January 1, 1986 The authors have measured the rates of ultrasonic B-mode speckle pattern changes as a function of the change in center frequency of the transmitted acoustical pulse under a variety of experimental conditions. Experimental results agree with a previous theo ... Full text Cite

Speckle pattern correlation with lateral aperture translation: experimental results and implications for spatial compounding.

Journal Article IEEE transactions on ultrasonics, ferroelectrics, and frequency control · January 1986 Full text Cite

Explososcan: A parallel processing technique for high speed ultrasound imaging with linear phased arrays

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · June 11, 1985 The data acquisition rate in medical ultrasonic imaging devices is limited by the acoustic propagation velocity in the tissues. Typically in such machines the image lines are produced sequentially one line per transmitted pulse. A parallel processing schem ... Full text Cite

Frequency independent ultrasound contrast-detail analysis.

Journal Article Ultrasound in medicine & biology · May 1985 An ultrasound contrast-detail phantom has been developed to evaluate the image quality of diagnostic ultrasound imaging systems. The phantom includes eight conical targets whose B-mode images show disk lesions such that the object contrast of each lesion r ... Full text Cite

A plane layered model to estimate in situ ultrasound exposures.

Journal Article Ultrasonics · January 1985 Determination of in situ ultrasound exposures in experimental animals and patients is necessary to assess any potential hazard of ultrasound implied by reported biological effects in animals. A layered model was used to calculate total attenuation of ultra ... Full text Cite

Explososcan: a parallel processing technique for high speed ultrasound imaging with linear phased arrays.

Journal Article The Journal of the Acoustical Society of America · April 1984 The data acquisition rate in medical ultrasonic imaging devices is limited by the acoustic propagation velocity in the tissues. Typically in such machines the image lines are produced sequentially one line per transmitted pulse. A parallel processing schem ... Full text Cite

Ultrasound speckle size and lesion signal to noise ratio: verification of theory.

Journal Article Ultrasonic imaging · April 1984 We compare predictions from our published theory of speckle cell size with recently published experimental results and a three dimensional computer simulation for the case of Gaussian pulses from spherically focused transducers in random media. The agreeme ... Full text Cite

Beam steering with linear arrays.

Journal Article IEEE transactions on bio-medical engineering · August 1983 Full text Cite

Beam steering with linear arrays

Journal Article IEEE Trans. Biomed. Eng. (USA) · 1983 The principles and techniques of real-time imaging with phased array ultrasound scanners are reviewed. Topics include (1) the geometric optics of beam steering and focusing with a linear array in the transmit and receive modes; (2) limitations on image dat ... Cite

LOW CONTRAST DETECTABILITY AND CONTRAST/DETAIL ANALYSIS IN MEDICAL ULTRASOUND.

Journal Article IEEE transactions on sonics and ultrasonics · 1983 The first- and second-order statistics of envelope detected ultrasound (US) B-mode images for the case of a scattering phantom with many scatterers per resolution cell have been previously derived. These characteristics are integrated over the region of a ... Cite

STATISTICS OF SPECKLE IN ULTRASOUND B-SCANS.

Journal Article IEEE transactions on sonics and ultrasonics · 1983 In the ultrasound imaging process, the complex summation at the transducer face is assumed to be linear. The envelope detection process in B-scanning is a nonlinear step which yields essentially the magnitude of the complex field or voltage. It is shown th ... Cite

THROUGH TRANSMISSION TECHNIQUE FOR ULTRASONIC ATTENUATION MEASUREMENT USING BROADBAND, PLANE WAVE PULSES.

Journal Article Ultrasonics Symposium Proceedings · January 1, 1983 Full text Cite

Statistics of Speckle in Ultrasound B-Scans

Journal Article IEEE Transactions on Sonics and Ultrasonics · January 1, 1983 In the ultrasound imaging process, the complex summation at the transducer face is assumed to be linear. The envelope detection process in B-scanning is a nonlinear step which yields essentially the magnitude of the complex field or voltage. (A square law ... Full text Cite

Low Contrast Detectability and Contrast/Detail Analysis in Medical Ultrasound

Journal Article IEEE Transactions on Sonics and Ultrasonics · January 1, 1983 The first- and second-order statistics of envelope detected ultrasound (US) B-mode images for the case of a scattering phantom with many scatterters per resolution cell have been previously derived. These characteristics are integrated over the region of a ... Full text Cite

Angular response of miniature ultrasonic hydrophones.

Journal Article Medical physics · July 1982 The voltage response of ceramic and polyvinylidene fluoride (PVDF) hydrophones was measured in the receive mode for angles of incidence ranging from 0 degrees to 90 degrees. The measurements were performed at 2.5, 3.5, 5.0, and 8.0 MHz; these frequencies a ... Full text Cite

A contrast-detail analysis of diagnostic ultrasound imaging.

Journal Article Medical physics · January 1982 For diagnostic ultrasound imaging, as in computed tomography, a feature of prime importance is the detection of focal lesions of varying size and contrast (echo amplitude) from surrounding tissue. This study describes a new tissue-stimulating phantom which ... Full text Cite

MEASUREMENTS AND ANALYSIS OF SPECKLE IN ULTRASOUND B-SCANS.

Journal Article Acoustical Imaging: Proceedings of the International Symposium · January 1, 1982 Full text Cite

CONTRAST-RESOLUTION PHANTOM FOR ULTRASOUND B-SCANS.

Journal Article · December 1, 1980 Cite

Prospects and limitations of diagnostic ultrasound

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · December 26, 1979 The current state of medical diagnostic ultrasound imaging is analyzed including discussions of present limitations and possible solutions of these problems. Ultrasound is unique in that tomographic images are formed from mechanical energy reflected from t ... Full text Cite

TISSUE EQUIVALENT UPPER ABDOMINAL PHANTOM FOR TRAINING AND EQUIPMENT DEMONSTRATION.

Journal Article · December 1, 1979 Cite

EVALUATION OF GRAY SCALE PHANTOM FOR DYNAMIC RANGE TESTING OF DIAGNOSTIC ULTRASOUND INSTRUMENTATION.

Journal Article · December 1, 1979 Cite

ADAPTIVE ULTRASOUND CEPHALIC IMAGING SYSTEM.

Journal Article · December 1, 1979 Cite

Angular Response of Piezoelectric Elements in Phased Array Ultrasound Scanners

Journal Article IEEE Transactions on Sonics and Ultrasonics · January 1, 1979 In the design of phased linear array sector scanners for medical applications, it is important to preserve uniform response at each angle throughout the sector scan of ± 45°. Examination of linear array transducers showed reduced transmit pressure and rece ... Full text Cite

A multiple frequency array for improved diagnostic imaging

Journal Article IEEE Trans. Sonics Ultrason. (USA) · 1978 A novel broadband array is described which consists of two transducer arrays of different frequencies (one at 1.5 MHz, the other at 2.5 MHz) mounted one above the other. This method of construction avoids the usual compromise between sensitivity and bandwi ... Cite

Quality assurance testing of an ultrasound B-scanner with the aium test object

Journal Article Medical Ultrasound · January 1, 1978 Cite

Real time ultrasound tomography of the adult brain.

Journal Article Stroke · 1978 Initial clinical results are reported from a new real time, 2-dimensional ultrasound scanner modified for adult cephalic applications. An optimized transducer design and the use of the dynamically focused phased array imaging system have resulted in ultras ... Full text Link to item Cite

A Multiple Frequency Array for Improved Diagnostic Imaging

Journal Article IEEE Transactions on Sonics and Ultrasonics · January 1, 1978 Cost and complexity of phased array diagnostic ultrasound imaging systems is related to the number of parallel channels during both transmit and receive. If the total number of active elements within a given aperture is reduced so that fewer parallel chann ... Full text Cite

Methods and results of dynamic range testing of diagnostic ultrasound instrumentation

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · December 27, 1977 The technological advance of gray scale imaging has been a major factor in the rapid growth of the clinical application of diagnostic ultrasound. Gray scale imaging implies that the displayed brightness of a target in the ultrasound image is a function of ... Full text Cite

Gray scale imaging with complex tgc and transducer arrays

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · March 25, 1976 Ultrasound imaging of soft tissues places severe demands on the design of imaging systems because of the large range of echo amplitudes which may be encountered at any point in the body. Simple TGC curves are often inadequate in producing optimum gray scal ... Full text Cite

SAMPLED APERTURE TECHNIQUES APPLIED TO B-MODE ECHOENCEPHALOGRAPHY.

Journal Article Acoust Hologr · January 1, 1975 An electronically steered and focused multielement transducer array is used in an attempt to minimize acoustic aberrations caused by skull thickness variations. Aberrations like this have thus far limited practical utilization of B-mode scanners in clinica ... Full text Cite

Schlieren study of pulsed ultrasound transmission through human skull.

Journal Article Journal of clinical ultrasound : JCU · March 1974 Full text Cite

STUDY OF NEAR FIELD ULTRASONIC BEAM PATTERNS FROM A PULSED LINEAR ARRAY.

Journal Article · January 1, 1974 Two methods of modeling and visualizing the pressure fields of pulsed planar arrays have been developed. One of these methods has been applied to interactive optimization of the zero**t**h order diffraction pattern for efficient cardiac imaging in the near ... Cite