To evaluate the diagnostic potential of the medullary vein sign as an imaging marker in neurosarcoidosis.

Neurosarcoidosis is a rare manifestation of sarcoidosis that can be inferred through the clinical presentation, cerebral spinal fluid (CSF) analysis, and magnetic resonance imaging (MRI) scans. However, its accurate diagnosis remains a significant challenge due to the variability in its diagnostic criteria and the overlapping clinical and imaging features with other conditions. One under-researched finding in these patients is the engorgement of the medullary vein on susceptibility-weighted imaging (SWI), termed as the 'medullary vein sign'; postulated to be a specific sign for neurosarcoidosis, its reliability has not yet been fully elucidated.

A single-center retrospective study was performed between March 31st, 2022, and August 1st, 2022. Two neuroradiologists independently examined MRI images using SWI/gradient echo sequences for medullary vein engorgement. A total of 32 patients were reviewed, and the diagnosis was based on imaging, biopsy, and CSF analysis. Finally, the sensitivity and specificity of the medullary vein sign were calculated.

Our findings confirm the high specificity of the medullary vein sign for neurosarcoidosis and suggest that SWI is an effective tool for early detection, especially compared to conventional MRI and CSF analysis. Incorporating this in the current diagnostic criteria may result in timely intervention, and we encourage radiologists to look for this marker in patients with suspected neurosarcoidosis.