Spinal subtraction MRI for diagnosis of epidural leakage in SIH

OBJECTIVE: To explore the efficacy of spinal MRI study with subtraction analysis as a rapid, reliable, and noninvasive procedure to detect epidural CSF collection in spontaneous intracranial hypotension (SIH) syndrome. METHODS: Seventeen patients (mean age 42 years, age range 17-65 years; 11 female) with SIH diagnosed using the International Classification of Headache Disorders criteria and 13 age-matched control subjects underwent standard sagittal spinal MRI. Postprocessing image analysis with subtraction of T1-weighted from T2-weighted MRI scans was performed and tested for the detection of the CSF leak. RESULTS: The CSF epidural collection was visible in all patients with SIH and was detected at the dorsal (16 of 17), cervical (13 of 17), lumbar (13 of 17), and sacral (12 of 17) levels. None of the control subjects showed a CSF leak. Diverticula were present in 23% of patients, whereas the actual site of the CSF leak was recognized in only one patient. Eight patients were treated conservatively, whereas 9 patients required an epidural blood patch, performed at a fixed L2-L3 or L3-L4 spinal level, with complete recovery. CONCLUSIONS: Spinal MRI with dedicated subtraction analysis could represent the first-line diagnostic tool in the management of patients with SIH, thus leaving invasive investigation for selected patients, such those requiring dural surgery.