MO‐D‐I‐609‐03: Fast Dynamic MR Imaging for Tracking Lung Tumor Motion During the Respiratory Cycle

Purpose: To compare two MR sequences, HASTE and trueFISP, to track lung tumor motion and to assess tumor conspicuity and image artifacts. Method and Materials: A lung tumor motion phantom, three healthy volunteers and two lung tumor patients were examined using a clinical 1.5‐T scanner (Sonata, Siemens, Germany) with the following parameters: trueFISP (TE/TR 1.5/204.2ms; FA/55^o; FOV/300×300; matrix/128×128; slice‐thickness/5mm), and HASTE (TE/TR 25/800ms; FA/160^o; FOV/325×400; matrix/123×256; slice‐thickness/5mm). No contrast agent or gating was used. Parenchyma signal intensity, lung regions and diaphragm displacement were measured in three healthy subjects. Tumor displacement, tumor SNR and tumor‐to‐parenchyma CNR were calculated in the two lung tumor patients. Tumor conspicuity and imaging artifacts were evaluated in all subjects by two radiation oncologists. Results: HASTE visualized better in peripheral vessels, but blurred tumor and central vessels. TrueFISP visualized better in non‐peripheral vessels, but demonstrated ghost artifacts in the phase‐encoding direction. Relative to CT, both sequences showed high SNR and CNR in patient ♯1 with the metastatic adenocarcinoma (HASTE 42.26/24.48; trueFISP 37.72/17.41; CT 42.04/29.98), but reduced SNR and CNR in patient ♯2 with the primary squamous cell carcinoma adenocarcinoma (HASTE 24.51/4.81; trueFISP 8.54/1.73; CT 36.67/26.84). Conclusion: HASTE and trueFISP can both monitor lung tumor motion during free breathing. Tumor conspicuity and imaging artifacts depend upon the tumor type, size and location. © 2005, American Association of Physicists in Medicine. All rights reserved.

Duke Scholars

Author Jing Cai Radiation Oncology