Hypointensity of the Motor Cortex in the Susceptibility Weighted Sequence: A Radiological Biomarker of Amyotrophic Lateral Sclerosis?

Abstract

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the progressive loss of upper and lower motor neurons (AMN) and resulting in loss of voluntary control of movement. The presence of hyposignal in the motor cortex on the magnetic susceptibility sequence (SWI) may indicate a lesion in the SMN. The aim was to verify the presence of hyposignal in the motor cortex on cranial magnetic resonance (MR) SWI in patients diagnosed with ALS. This is a descriptive study that evaluated data from 20 ALS patients and 20 controls. The statistical significance of the variables was verified using the t test and the linear regression test, with alpha levels of 0.01 and 0.05, respectively. Clinical variables did not statistically influence the presence of hyposignal in the motor cortex of patients with ALS, but in the control group there was statistical significance of age in the presence of hyposignal, being more present in the elderly. When comparing the presence of hyposignal in patients with ALS and healthy individuals, there was a static difference, being more frequent in patients with ALS. There was also a statistical influence of MT hypersignal on the presence of hyposignal in the motor cortex in SWI. It was concluded that the presence of hyposignal in the motor cortex of patients with ALS is not influenced by clinical variables, despite being more frequent in patients with ALS than in healthy individuals. Age can influence the presence of hyposignal in healthy individuals, but in the ALS group there was no such relationship, which may suggest neurodegeneration. Patients who had hyposignal in the cortex also had hypersignal in the LMCA, which would make it possible to use the SWI as another tool for detecting lesions in the SMN and, thus, help in the final diagnosis of ALS.