Preliminary assessment of amyotrophic lateral sclerosis by using MRI and MR diffusion tensor imaging / 中华放射学杂志

ABSTRACT

Objective To describe the characteristic MR findings in the brain in patients with amyotrophic lateral sclerosis (ALS), and to assess the diagnostic value of conventional MR imaging and fractional anisotropy (FA) of diffusion tensor imaging (DTI). Methods Conventional MR imaging was performed in 14 clinically proved ALS patients and 12 age-matched normal controls. Contrast enhanced MR images were acquired in 2 patients. Axial and coronal DTI scans were performed in 10 patients and 12 normal controls with SE-EPI sequence. The b value was 1 000 s/mm 2, the number of diffusion sensitive gradient direction was 25. For quantitative assessment of the corticospinal tract (CST), FA value of bilateral CST was measured at the level of posterior limb (PL) of the internal capsule (IC) and the cerebral peduncle of the midbrain, respectively, and statistical analysis was performed. Results Focal slight low signal intensity on T 1WI and high signal intensity (hyperintense to gray matter) on T 2WI was demonstrated in 6 ALS cases (42.9%) in bilateral PL of the IC, and the high signal was longitudinally continuous from the PL to the cerebral peduncle on T 2WI coronal plane, corresponding to the course of CST. In another 8 ALS cases (57.1%), the focal slight low signal intensity on T 1WI and slight high signal intensity (isointense to gray matter) on T 2WI was revealed in bilateral PL of the IC. No abnormal contrast enhancement was detected in the 2 cases. In control group, the focal slight low signal intensity on T 1WI and slight high signal intensity (isointense to gray matter) on T 2WI was demonstrated in all 12 subjects in bilateral PL of the IC. FA values of the patient group were significantly lower than that of the control group at the level of the PL of the IC (F=7.38, P