Presentation
Low back pain and bilateral radiculopathy.
Patient Data
Lower lumbar and sacral regions intraspinal extra-axial collection involving subdural space along the ventral and dorsal aspects, preserving epidural fat, and exerting a mass effect upon cauda equina roots. They elicit high signal on T1 and low signal on T2 (early subacute blood; intracellular methemoglobin). "Inverted Mercedes-Benz sign' could be noted on axial T1WI.
The annotated image clarifies "Inverted Mercedes-Benz sign".
Case Discussion
The spinal subdural hematoma is a rare entity and it is much less common than the spinal epidural hematoma. On MRI, a preserved epidural fat is an important differentiating feature. The subdural blood collects in a special configuration known on imaging as "Inverted Mercedes-Benz sign" with one anterior and two posterolateral collections limited by two lateral denticulate ligaments and a midline dorsal septum.