Physics and Imaging in Radiation Oncology Analyses of regional radiosensitivity of white matter structures along tract axes using novel white matter segmentation and diffusion imaging biomarkers  Jordan Houri, Roshan Karunamuni, Michael Connor, Niclas Pettersson, Carrie McDonald, Nikdokht Farid, Nathan White, Anders Dale, Jona A. Hattangadi-Gluth, Vitali Moiseenko  Physics and Imaging in Radiation Oncology  Volume 6, Pages 39-46 (April 2018) DOI: 10.1016/j.phro.2018.04.003 Copyright © 2018 The Authors Terms and Conditions

Fig. 1 Voxel-wise (top) and slice-wise (bottom) analysis for the corticospinal tract; Top Left: 3D view of Tract-Crawler volumetric sections; Axes are labeled such that A (Axial), S (Sagittal) and C (Coronal) represent the Superior-Inferior, Left-Right and Anterior-Posterior directions, respectively. Bottom Left: 3D view of Tract-Crawler slices overlaid on right hemisphere tract structure; Middle column: FA (rows 1 and 3) and MD (rows 2 and 4) relative sensitivities versus distance along the medial axis for the left hemispheres; Right column: FA (rows 1 and 3) and MD (rows 2 and 4) relative sensitivities versus distance along the medial axis for the right hemispheres; Error bars are 95% confidence intervals. Asterisks denote data with p < 0.05. Physics and Imaging in Radiation Oncology 2018 6, 39-46DOI: (10.1016/j.phro.2018.04.003) Copyright © 2018 The Authors Terms and Conditions

Fig. 2 Voxel-wise analyses for the medial lemniscus (top) and inferior cerebellar peduncle (bottom); Top and Bottom Left: 3D view of Tract-Crawler volumetric sections; Axes labeling as in Fig. 1. Middle column: FA (rows 1 and 3) and MD (rows 2 and 4) relative sensitivities versus distance along the medial axis for the left hemispheres; Right column: FA (rows 1 and 3) and MD (rows 2 and 4) relative sensitivities versus distance along the medial axis for the right hemispheres; Error bars are 95% confidence intervals. Asterisks denote data with p < 0.05. Physics and Imaging in Radiation Oncology 2018 6, 39-46DOI: (10.1016/j.phro.2018.04.003) Copyright © 2018 The Authors Terms and Conditions

Fig. 3 Voxel-wise analysis for the inferior cerebellar peduncle relative to the pre-RT FA without scaling relative to the tract mean. Physics and Imaging in Radiation Oncology 2018 6, 39-46DOI: (10.1016/j.phro.2018.04.003) Copyright © 2018 The Authors Terms and Conditions

Fig. 4 Voxel-wise association scatterplots for sensitivities in FA (left) and MD (right) for right versus left hemisphere, parametrized by distance along the medial axis, for the corticospinal tract, medial lemniscus, and inferior cerebellar peduncle, p < 0.01 in all cases. Physics and Imaging in Radiation Oncology 2018 6, 39-46DOI: (10.1016/j.phro.2018.04.003) Copyright © 2018 The Authors Terms and Conditions

Supplementary Fig. S1 Visualization of the medial axis smoothing process performed on the right inferior cerebellar peduncle; Axes labeling as in Fig. 1. (a) Medial axis by thinning with no smoothing processes, (b) 3-dimensional parametric cubic spline fit to the medial axis with no resampling of points, (c) 3-dimensional parametric cubic spline fit to the medial axis with 6 control points (optimal smoothness), and (d) 3-dimensional parametric cubic spline fitted to the medial axis with only 2 control points, i.e. the endpoints of the tract. Physics and Imaging in Radiation Oncology 2018 6, 39-46DOI: (10.1016/j.phro.2018.04.003) Copyright © 2018 The Authors Terms and Conditions

Supplementary Fig. S2 Voxel-wise cingulum (cingulate gyrus); Left Panel: 3D view of Tract-Crawler slices overlaid on the right hemisphere tract structure; Axes labeling as in Fig. 1. Middle and right columns: FA (top) and MD (bottom) relative sensitivities versus distance along the medial axis for the left (middle column) and right (right column) hemispheres. Error bars are 95% confidence intervals. Physics and Imaging in Radiation Oncology 2018 6, 39-46DOI: (10.1016/j.phro.2018.04.003) Copyright © 2018 The Authors Terms and Conditions