• ALS
• corticospinal
• degeneration
• degenerative
• gradient
• motor neuron
• MR
• MRI
• QSM
• SWAN

Purpose – To investigate both sensitivity and accuracy of T2*-weighted images of primary motor cortex in revealing patients affected by ALS. To find with quantitative susceptibility mapping a susceptibility cut-off value which had the best sensitivity and specificity at detecting upper motor neuron burden. To evaluate further relationships between imaging and clinical data.

Material and methods - 74 patients and 17 controls were investigated on a 3T MR scanner. Protocol included T2*-weighted acquisitions for both qualitative and quantitative imaging, by obtaining QSM. Magnetic susceptibility was measured within different rolandic regions. Data were compared with clinical assessment of disease in patients.

Results - Based on qualitative images alone, 2 blind readers could identify most clinically compromised patients with a high interobserver agreement. A magnetic susceptibility cut-off value of 0,064 ppm was set as threshold to differentiate effectively patients from healthy controls. Appearance on qualitative imaging and susceptibility magnetic values of specific regions in primary motor cortex varied accordingly to symptomatic body districts.

Conclusions - T2*-weighted qualitative imaging is a reliable way to assess UMN disease at 3T MRI. T2* hypointensity distribution within primary motor cortex is related to the localization of clinical symptoms. QSM is capable of measuring magnetic susceptibility values in affected cortical regions, identifying ALS patients with great accuracy.