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Estimation of in vivo noise in clinical CT images: comparison and validation of three different methods against ensemble noise gold-standard

Publication ,  Journal Article
Ria, F; Smith, T; Abadi, E; Solomon, J; Samei, E
Published in: Proc. SPIE 11595, Medical Imaging 2021: Physics of Medical Imaging, 115952P
February 15, 2021

Image quality estimation is crucial in modern CT with noise magnitude playing a key role. Several methods have been proposed to estimate noise surrogates in vivo. This study aimed to ascertain the accuracy of three different noise-magnitude estimation methods. We used ensemble noise as the ground truth. The most accurate approach to assess ensemble noise is to scan a patient repeatedly and assess the noise for each pixel across the ensemble of images. This process is ethically undoable on actual patients. In this study, we surmounted this impasse using Virtual Imaging Trials (VITs) that simulate clinical scenarios using computer-based simulations. XCAT phantoms were imaged 47 times using a scanner-specific simulator (DukeSim) and reconstructed with filtered back projection (FBP) and iterative (IR) algorithms. Noise magnitudes were calculated in lung (ROIn), soft tissues (GNI), and air surrounding the patient (AIRn), applying different HU thresholds and techniques. The results were compared with the ensemble noise magnitudes within soft tissue (En). For the FBP-reconstructed images, median En was 30.6 HU; median ROIn was 46.6 HU (+52%), median GNI was 40.1 HU (+31%), and median AIRn 25.1 HU (-18%). For the IR images, median En was 19.5 HU; median ROIn was 31.2 HU (+60%), median GNI was 25.1 HU (+29%), and median AIRn 18.8 HU (-4%). Compared to ensemble noise, GNI and ROIn overestimate the tissue noise, while AIRn underestimates it. Air noise was least representative of variations in tissue noise due to imaging condition. These differences may be applied as adjustment or calibration factors to better represent clinical results.

Duke Scholars

Published In

Proc. SPIE 11595, Medical Imaging 2021: Physics of Medical Imaging, 115952P

Publication Date

February 15, 2021

Volume

115952P

Start / End Page

1 / 7
 

Citation

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Ria, F., Smith, T., Abadi, E., Solomon, J., & Samei, E. (2021). Estimation of in vivo noise in clinical CT images: comparison and validation of three different methods against ensemble noise gold-standard. Proc. SPIE 11595, Medical Imaging 2021: Physics of Medical Imaging, 115952P, 115952P, 1–7.
Ria, Francesco, Taylor Smith, Ehsan Abadi, Justin Solomon, and Ehsan Samei. “Estimation of in vivo noise in clinical CT images: comparison and validation of three different methods against ensemble noise gold-standard.” Proc. SPIE 11595, Medical Imaging 2021: Physics of Medical Imaging, 115952P 115952P (February 15, 2021): 1–7.
Ria F, Smith T, Abadi E, Solomon J, Samei E. Estimation of in vivo noise in clinical CT images: comparison and validation of three different methods against ensemble noise gold-standard. Proc SPIE 11595, Medical Imaging 2021: Physics of Medical Imaging, 115952P. 2021 Feb 15;115952P:1–7.
Ria, Francesco, et al. “Estimation of in vivo noise in clinical CT images: comparison and validation of three different methods against ensemble noise gold-standard.” Proc. SPIE 11595, Medical Imaging 2021: Physics of Medical Imaging, 115952P, vol. 115952P, Feb. 2021, pp. 1–7.
Ria F, Smith T, Abadi E, Solomon J, Samei E. Estimation of in vivo noise in clinical CT images: comparison and validation of three different methods against ensemble noise gold-standard. Proc SPIE 11595, Medical Imaging 2021: Physics of Medical Imaging, 115952P. 2021 Feb 15;115952P:1–7.

Published In

Proc. SPIE 11595, Medical Imaging 2021: Physics of Medical Imaging, 115952P

Publication Date

February 15, 2021

Volume

115952P

Start / End Page

1 / 7