Evaluation of automatic contour propagation in T2‐weighted 4 DMRI for normal‐tissue motion assessment using internal organ‐at‐risk volume ( IRV )

作者：Jingjing Zhang, Svetlana V. Markova, Alejandro Garcia, Kirk Huang, Xingyu Nie, Wookjin Choi, Wei Lü, Abraham J. Wu, Andreas Rimner, Guang Li · 发表于：Journal of Applied Clinical Medical Physics · 年份：2018 · DOI：10.1002/acm2.12431 · 被引用次数：11 · 研究领域：Advanced Radiotherapy Techniques、Advanced MRI Techniques and Applications、MRI in cancer diagnosis

PURPOSE: The purpose of this study was to evaluate the quality of automatically propagated contours of organs at risk (OARs) based on respiratory-correlated navigator-triggered four-dimensional magnetic resonance imaging (RC-4DMRI) for calculation of internal organ-at-risk volume (IRV) to account for intra-fractional OAR motion. METHODS AND MATERIALS: T2-weighted RC-4DMRI images were of 10 volunteers acquired and reconstructed using an internal navigator-echo surrogate and concurrent external bellows under an IRB-approved protocol. Four major OARs (lungs, heart, liver, and stomach) were delineated in the 10-phase 4DMRI. Two manual-contour sets were delineated by two clinical personnel and two automatic-contour sets were propagated using free-form deformable image registration. The OAR volume variation within the 10-phase cycle was assessed and the IRV was calculated as the union of all OAR contours. The OAR contour similarity between the navigator-triggered and bellows-rebinned 4DMRI was compared. A total of 2400 contours were compared to the most probable ground truth with a 95% confidence level (S95) in similarity, sensitivity, and specificity using the simultaneous truth and performance level estimation (STAPLE) algorithm. RESULTS: Visual inspection of automatically propagated contours finds that approximately 5-10% require manual correction. The similarity, sensitivity, and specificity between manual and automatic contours are indistinguishable (P > 0.05). The Jaccard sim...