MRI-FLAIR images of the head show corticospinal tract alterations in ALS patients more frequently than T2-, T1- and proton-density-weighted images

In some patients with amyotrophic lateral sclerosis (ALS), T2-weighted and proton-density weighted magnetic resonance imaging (MRI) shows hyperintense or hypointense signals at the corticospinal tract. Fluid-attenuated invers ion recovery (FLAIR) sequences increase the sensitivity of MRI to detect co rtical and subcortical tissue changes. In 31 ALS patients and 33 controls, we studied the frequency and the extent of signal abnormalities in FLAIR im ages compared to T2-, T1- and proton-density-weighted images. Hyperintense signals at the corticospinal tract were significantly more frequent in FLAI R images than in all other tested sequences. In FLAIR images of ALS patient s only, distinct hyperintense signals at the subcortical precentral gyrus ( five patients), the centrum semiovale (eight patients), the crus cerebri (n ine patients) and the pens (four patients) as well as mild hyperintense sig nals in the medulla oblongata (three patients) were seen. More frequently, but not exclusively in ALS patients, FLAIR images showed mild hyperintense signals at the subcortical precentral gyrus (15 patients vs. 1 control). Qu antitative analysis confirmed the significant difference between ALS patien ts and controls at the subcortical precentral gyrus in FLAIR images. In T1- weighted images, the corticospinal tract at the capsula interna was hypoint ense in significantly more controls than ALS patients. Also this difference was confirmed in the quantitative analysis. Similar to previous results, MR image alterations did correlate poorly to clinical data of upper motor n euron affliction. MR images of the head, including FLAIR images, provide ad ditional information regarding corticospinal tract involvement in ALS patie nts. Because of an overlap with physiological findings, they have to be int erpreted cautiously, with the exception of hyperintense signals at the subc ortical precentral gyrus. (C) 2001 Elsevier Science B.V. All rights reserve d.