Prone Digital Subtraction Myelography vs Dynamic CT Myelography for Detecting Definite Type 1 CSF Leak in Spontaneous Intracranial Hypotension.

BACKGROUND AND PURPOSE: Ventral dural tears (type 1) are a major cause of spontaneous intracranial hypotension (SIH) and require precise localization for targeted treatment. Although prone digital subtraction myelography (DSM) and dynamic CT myelography (dCTM) are standard diagnostic modalities, their diagnostic performance has not been directly compared. We aimed to evaluate the diagnostic yield and radiation exposure of prone DSM compared with dCTM in a paired cohort.

MATERIALS AND

METHODS

In this ambispective study, we analyzed 39 patients with type 1 leaks who underwent both prone DSM and dCTM at a single tertiary center between July 2024 and September 2025. All images were independently re-evaluated by a blinded neurointerventionist using the Spontaneous Intracranial Hypotension Reporting and Data System (SIH-RADS) scoring system. The primary outcome was the rate of successful localization, defined as SIH-RADS category 5. Secondary outcomes included the effective radiation dose and interrater reliability.

RESULTS

Successful localization was achieved in 31 patients (79.5%) using prone DSM and in 33 patients (84.6%) using dCTM, with no statistically significant difference between the 2 modalities (P = .72). Concordant localization was observed in 28 patients (71.8%). The median effective radiation dose of prone DSM was approximately half that of dCTM (P < .001). Diagnostic failures in DSM were primarily attributed to artifacts at the cervicothoracic junction, which were avoidable using the swimmer's position in most patients, whereas failures in dCTM were associated with temporal limitations or technical failures.

CONCLUSIONS

Prone DSM and dCTM demonstrated comparably high diagnostic yields for localizing type 1 leaks. However, DSM offered a significant advantage in radiation safety. When available and supported by appropriate expertise, prone DSM may be considered a preferred first-line technique, with dCTM serving as a complementary option.