Value of quantitative analysis of routine clinical MRI sequences in ALS

Simple morphological assessment of conventional MRI used in routine neurological diagnostic work-up lacks sensitivity and specificity for amyotrophic lateral sclerosis (ALS). Quantitative analysis of routine MRI sequences might, however, be more suitable to reveal ALS-related pathological cerebral alterations. We investigated 10 ALS patients and 10 age- and sex-matched healthy controls by MRI. Brain maps of T2 relaxation time (T2), relative proton density (PD), and apparent diffusion coefficient (ADC) were obtained. Values of these parameters were measured in 22 selected brain regions, and compared among the patients and the controls by using paired t-test with Bonferroni corrected alpha level (= 0.002). In ALS patients, increased PD was found in the pyramidal tract, corpus callosum, and white and grey matter. T2 elongation was found at the genu of corpus callosum, and at the posterior limb of the internal capsule (ICP). ADC values showed a tendency towards an increase in patients, which was only significant at the ICP. PD therefore appeared to be the most sensitive parameter for the detection of degenerative changes not only in the motor system but also in extramotor brain regions.