Dose-dependent white matter damage after brain radiotherapy

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• 作者：Michael Connor^a ; Roshan Karunamuni^a ; ^e ; Carrie McDonald^a ; ^c ; ^e ; Nathan White^b ; ^e ; Niclas Pettersson^a ; Vitali Moiseenko^a ; Tyler Seibert^a ; ^e ; Deborah Marshall^a ; Laura Cervino^a ; Hauke Bartsch^b ; ^e ; Joshua Kuperman^b ; ^e ; Vyacheslav Murzin^a ; Anitha Krishnan^b ; ^e ; Nikdokht Farid^b ; ^e ; Anders Dale^b ; ^c ; ^d ; ^e ; Jona Hattangadi-Gluth^a ; ^e ; ^{jhattangadi@ucsd.edu}
• 关键词：Diffusion tensor imaging ; MRI ; White matter ; Radiotherapy ; b-Value ; Radiation
• 刊名：Radiotherapy and Oncology
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：121
• 期：2
• 页码：209-216
• 全文大小：1317 K
• 卷排序：121

文摘

Brain radiotherapy is limited in part by damage to white matter, contributing to neurocognitive decline. We utilized diffusion tensor imaging (DTI) with multiple b-values (diffusion weightings) to model the dose-dependency and time course of radiation effects on white matter.Materials and methodsFifteen patients with high-grade gliomas treated with radiotherapy and chemotherapy underwent MRI with DTI prior to radiotherapy, and after months 1, 4–6, and 9–11. Diffusion tensors were calculated using three weightings (high, standard, and low b  -values) and maps of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (λ∥)(λ∥), and radial diffusivity (λ⊥λ⊥) were generated. The region of interest was all white matter.ResultsMD, λ∥λ∥, and λ⊥λ⊥ increased significantly with time and dose, with corresponding decrease in FA. Greater changes were seen at lower b-values, except for FA. Time–dose interactions were highly significant at 4–6 months and beyond (p < .001), and the difference in dose response between high and low b-values reached statistical significance at 9–11 months for MD, λ∥λ∥, and λ⊥λ⊥ (p < .001, p < .001, p = .005 respectively) as well as at 4–6 months for λ∥λ∥ (p = .04).ConclusionsWe detected dose-dependent changes across all doses, even <10 Gy. Greater changes were observed at low b-values, suggesting prominent extracellular changes possibly due to vascular permeability and neuroinflammation.