Zebra sign of precentral gyri in amyotrophic lateral sclerosis: A novel finding using phase difference enhanced (PADRE) imaging-initial results.

Objective: We compared the precentral gyri (PG) on the PADRE of patients with amyotrophic lateral sclerosis (ALS) and healthy subjects (HSs) in order to determine whether it is possible to discriminate between ALS patients and HSs on an individual basis.

Methods: First, two radiologists reviewed the appearance of the normal PG and that of ALS patients on PADRE in a non-blinded manner, and deviations from the appearance of the normal PG were recorded. Next, based on the presence of PG abnormalities on PADRE, we performed an observer performance study using 16 ALS patients and 16 HSs.

Results: The radiologists were able to consensually define the PG as abnormal on PADRE when a low-signal-intensity layer was observed in the gray matter of the PG; a three- or four-layer organization (zebra sign) was characterized by the low-signal-intensity layer. The observer performance study demonstrated that the sensitivity, specificity, and accuracy of PG abnormalities on PADRE for discriminating ALS patients from HSs were 94 %, 94 %, and 94 %, respectively, for reviewers 1 and 2.

Conclusions: It was possible to discriminate between ALS patients and HSs based on the presence of PG abnormalities on PADRE, which may reflect upper motor neuron impairment in ALS.

Key Points: • PADRE reveals low-signal-intensity layer in the PG of ALS • By PADRE findings on PG, we can discriminate ALS from HSs • PADRE may be a useful method for detecting UMN impairment in ALS.