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Multi‐component diffusion characterization of radiation‐induced white matter damage
Author(s) -
Karunamuni Roshan A.,
White Nathan S.,
McDonald Carrie R.,
Connor Michael,
Pettersson Niclas,
Seibert Tyler M.,
Kuperman Joshua,
Farid Nikdokht,
Moiseenko Vitali,
Dale Anders M.,
HattangadiGluth Jona A.
Publication year - 2017
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1002/mp.12170
Subject(s) - white matter , diffusion mri , diffusion , diffusion imaging , radiation , nuclear medicine , nuclear magnetic resonance , effective diffusion coefficient , dosimetry , radiation dose , medicine , physics , magnetic resonance imaging , optics , radiology , thermodynamics
Purpose We used multi‐b‐value diffusion models to characterize microstructural white matter changes after brain radiation into fast and slow components, in order to better understand the pathophysiology of radiation‐induced tissue damage. Methods Fourteen patients were included in this retrospective analysis with imaging prior to, and at 1, 4–5, and 9–10 months after radiotherapy ( RT ). Diffusion signal decay within brain white matter was fit to a biexponential model to separate changes within the slow and fast components. Linear mixed‐effects models were used to obtain estimates of the effect of radiation dose and time on the model parameters. Results We found an increase of 0.11 × 10 −4 and 0.14 × 10 −4 mm 2 /s in the fast diffusion coefficient per unit dose–time (Gy‐month) in the longitudinal and transverse directions, respectively. By contrast, the longitudinal slow diffusion coefficient decreased independently of dose, by 0.18 × 10 −4 , 0.16 × 10 −4 , and 0.098 × 10 −4 mm 2 /s at 1, 4, and 9 months post‐ RT , respectively. Conclusions Radiation‐induced white matter changes in the first year following RT are driven by dose‐dependent increases in the fast component and dose‐independent decreases in the slow component.