Morphological changes after cranial fractionated photon radiotherapy: Localized loss of white matter and grey matter volume with increasing dose. (November 2021)

• Record Type: Journal Article
• Authors: Nagtegaal, S.H.J.; David, S; van Grinsven, E.E.; van Zandvoort, M.J.E.; Seravalli, E.; Snijders, T.J; Philippens, M.E.P.; Verhoeff, J.J.C.
• Is Part Of: Clinical and translational radiation oncology. Volume 31(2021)
• Page Start: 14
• Page End: 20
• Publication Date: 2021-11
• Subjects: CAT12 Computational Anatomy Toolbox 12 -- CSF cerebrospinal fluid -- CT computed tomography -- DBM deformation based morphometry -- FWER family-wise error rate -- GM grey matter -- IMPT intensity modulated proton therapy -- MNI Montreal Neurological Institute -- MRI magnetic resonance imaging -- PALM permutation analysis of linear models -- PTV planning target volume -- RT radiotherapy -- SNR signal to noise ratio -- TFCE Threshold-Free Cluster Enhancement -- TFE turbo fast echo -- TIV total intracranial volume -- VBM voxel-based morphometry -- VMAT volumetric modulated arc therapy; Radiotherapy -- Brain neoplasms -- Gray matter -- White matter; Cancer -- Radiotherapy -- Periodicals; Oncology -- Periodicals; Cancer -- Radiotherapy; Oncology; Radiation Oncology; Neoplasms -- radiotherapy; Translational Medical Research; Periodicals; Electronic journals; Periodicals; 616.9940642
• DOI: 10.1016/j.ctro.2021.08.010
• Languages: English
• ISSNs: 2405-6308

Abstract

Highlights: The entire brain is susceptible to dose-dependent volume loss after RT. Future studies should examine the impact of cerebral volume loss on cognition. Current sparing strategies in RT for brain tumours may need to be reconsidered. Abstract: Purpose: Numerous brain MR imaging studies have been performed to understand radiation-induced cognitive decline. However, many of them focus on a single region of interest, e.g. cerebral cortex or hippocampus. In this study, we use deformation-based morphometry (DBM) and voxel-based morphometry (VBM) to measure the morphological changes in patients receiving fractionated photon RT, and relate these to the dose. Additionally, we study tissue specific volume changes in white matter (WM), grey matter (GM), cerebrospinal fluid and total intracranial volume (TIV). Methods and materials: From our database, we selected 28 patients with MRI of high quality available at baseline and 1 year after RT. Scans were rigidly registered to each other, and to the planning CT and dose file. We used DBM to study non-tissue-specific volumetric changes, and VBM to study volume loss in grey matter. Observed changes were then related to the applied radiation dose (in EQD2). Additionally, brain tissue was segmented into WM, GM and cerebrospinal fluid, and changes in these volumes and TIV were tested. Results: Performing DBM resulted in clusters of dose-dependent volume loss 1 year after RT seen throughout the brain. Both WM and GM were affected; within the latter both cerebral cortex and subcortical nuclei show volume loss. Volume loss rates ranging from 5.3 to 15.3%/30 Gy were seen in the cerebral cortical regions in which more than 40% of voxels were affected. In VBM, similar loss rates were seen in the cortex and nuclei. The total volume of WM and GM significantly decreased with rates of 5.8% and 2.1%, while TIV remained unchanged as expected. Conclusions: Radiotherapy is associated with dose-dependent intracranial morphological changes throughout the entire brain. Therefore, we will consider to revise sparing of organs at risk based on future cognitive and neurofunctional data.