Chemotherapy-related toxicity affected both gray matter (GM) and white matter (WM), according to a recent study. WM was further affected by focal T1-weighted lesion-related pathologies and long-term rates of GM and WM atrophy were comparable to those of normal-aging. GM and WM volume changes were calculated from serial baseline and follow-up magnetic resonance imaging (MRI) ranging from 1.5 to 10.5 years in 19 MS patients treated with IA/aHSCT. A mixed-effects model with 2 predictors (total busulfan dose and baseline T1-weighted WM lesion volume “T1LV”) characterized the time-courses after IA/aHSCT. Researchers found:

• Accelerated short-term atrophy of 2.1% and 3.2% occurred in GM and WM, respectively, on average.
• Both busulfan dose and T1LV were significant predictors of WM atrophy, whereas only busulfan dose was a significant predictor of GM atrophy.
• Compared to baseline, a significant reduction in GM atrophy, not WM atrophy, was found.
• The average rates of long-term GM and WM atrophy were −0.18%/year (standard error [SE]: 0.083) and −0.07%/year (SE: 0.14), respectively.