Comparison of Diffusion-Weighted MR Imaging and T2-Weighted MR Imaging in Patients with Amyotrophic Lateral Sclerosis

The purpose of this study was to compare diffusion-weighted MR imaging with conventional MR sequences in patients with amyotrophic lateral sclerosis (ALS) and controls, and to assess the diagnostic value of diffusion-weighted imaging in the ALS patients. Twelve patients with ALS (ten men and two women, mean age 56 years) and 12 age-matched control subjects were studied with axial diffusion-weighted imaging and conventional MR imaging. Three adjacent slices of diffusion-weighted imaging were obtained at the level of the internal capsule. The diffusion-weighted imaging was performed with a b-value from 165-600 s/mm(2). Identical slices of diffusion-weighted images and conventional MR images were evaluated by a consensus reading. Diffusion-weighted images showed high signal intensity in the corticospinal tract at the level of the internal capsule in 11/12 patients with ALS (92%) and 5/12 control subjects (42%), whereas T2-weighted images (T2WI) revealed high signal intensity in the corticospinal tract in 11/12 patients with ALS (92%) and 8/12 control subjects (67%). The proton-weighted images (PDWI) disclosed the high signal corticospinal tract in 5/12 patients with ALS (42%), but not in any of the control subjects. Considering ALS patients versus control subjects, statistical analysis demonstrated that diffusion-weighted imaging (p=0.027, X(2) test) and proton-weighted imaging (p=0.037) were more specific than T2-weighted imaging. Diffusion-weighted imaging and proton-weighted imaging were more specific than T2-weighted imaging. The combination of diffusion-weighted imaging and T2WI/PDWI seems a promising tool in the diagnosis of amyotrophic lateral sclerosis.