Readout-segmented echo-planar diffusion-weighted imaging improves geometric performance for image-guided radiation therapy of pelvic tumors

Foltz, W. D., Porter, D. A., Simeonov, A., Aleong, A., Jaffray, D., Chung, P., Han, K. and Ménard, C. (2015) Readout-segmented echo-planar diffusion-weighted imaging improves geometric performance for image-guided radiation therapy of pelvic tumors. Radiotherapy and Oncology, 117(3), pp. 525-531. (doi: 10.1016/j.radonc.2015.07.046) (PMID:26264185)

Abstract

Background and purpose: Diffusion-weighted imaging using echo-planar imaging (EPI) is prone to geometric inaccuracy, which may limit application to image-guided radiation therapy planning, as well as for voxel-based quantitative multi-parametric or multi-modal approaches. This research investigates pelvic applications at 3 T of a standard single-shot (ssEPI) and a prototype readout-segmented (rsEPI) technique. Materials and methods: Apparent diffusion coefficient (ADC) accuracy and geometric performance of rsEPI and ssEPI were compared using phantoms, and in vivo, involving 8 patients prior to MR-guided brachytherapy for locally advanced cervical cancer, and 19 patients with prostate cancer planned for tumor-targeted radiotherapy. Global and local deviations in geometric performance were tested using Dice Similarity Coefficients (DC) and Hausdorff Distances (HD). Results: In cervix patients, DC increased from 0.76 ± 0.14 to 0.91 ± 0.05 for the high risk clinical target volume, and 0.62 ± 0.26 to 0.85 ± 0.08 for the gross tumor target volume. Tumors in the peripheral zone of the prostate gland were partly projected erroneously outside of the posterior anatomic boundary of the gland by 3.1 ± 1.6 mm in 11 of 19 patients using ADC-ssEPI but not with ADC-rsEPI. Conclusions: Both cervix and prostate ssEPI are prone to clinically relevant geometric distortions at 3 T. rsEPI provides improved geometric performance without post-processing.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Porter, Professor David
• Authors: Foltz, W. D., Porter, D. A., Simeonov, A., Aleong, A., Jaffray, D., Chung, P., Han, K., and Ménard, C.
• College/School: College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
• Journal Name: Radiotherapy and Oncology
• Publisher: Elsevier
• ISSN: 0167-8140
• ISSN (Online): 1879-0887
• Published Online: 08 August 2015