“…Accurate diagnosis, in particular, the differentiation from other arachnopathies is crucial, as progression can result in severe disability in untreated patients. In conventional MRI studies, diagnostic criteria rely on the so-called "scalpel sign" [18][19][20][21][22] which is a characteristic focal dorsal indentation of the spinal cord resembling a scalpel blade. This finding, first described by Reardon et al in 2013 22 , is considered pathognomonic of SAW.…”