Diagnostic Yield of Decubitus CT Myelography for Detection of CSF-Venous Fistulas

Jacob T Gibby; Timothy J Amrhein; Derek S Young; Jessica L Houk; Peter G Kranz

doi:10.3174/ajnr.A8330

Diagnostic Yield of Decubitus CT Myelography for Detection of CSF-Venous Fistulas

AJNR Am J Neuroradiol. 2024 May 7:ajnr.A8330. doi: 10.3174/ajnr.A8330. Online ahead of print.

Authors

Jacob T Gibby¹, Timothy J Amrhein¹, Derek S Young¹, Jessica L Houk¹, Peter G Kranz¹

Affiliation

¹ From the Department of Radiology (J.T.G., T.J.G., D.S.Y., J.L.H., P.G.K), Duke University Hospital, Durham, NC, USA.

PMID: 38719613
DOI: 10.3174/ajnr.A8330

Abstract

Background and purpose: Various imaging techniques have been described to detect CSF-Venous Fistulas (CVFs) in the setting of Spontaneous Intracranial Hypotension (SIH), including decubitus CT myelography (dCTM). The expected diagnostic yield of dCTM for CVF detection is not fully established. The purpose of this study was to assess the yield of dCTM among consecutive patients presenting for evaluation of possible SIH, and to examine what impact brain MRI findings of SIH had on diagnostic yield.

Materials and methods: Single-center, retrospective cohort of consecutive patients presenting over a one-year period who underwent CTM and had no CSF identified in the epidural space. Patients with epidural CSF leaks were included in a secondary cohort. Subjects were grouped according to positioning for the myelogram, either decubitus or prone, and the presence of imaging findings of SIH on pre-procedure brain MRI. Diagnostic yields for each subgroup were calculated, and the yield of dCTM was compared to prone CTM.

Results: The study cohort included 302 subjects, including 247 patients with no epidural fluid. Diagnostic yield of dCTM for CVF detection among subjects with positive brain MRI and no epidural fluid was 73%. No CVFs were identified among subjects with negative brain imaging. Among subjects with epidural leak, brain MRI was negative for signs of SIH in 22%. Prone CTM identified a CVF less commonly than dCTM (43% vs. 73%, p=0.19), although the difference was not statistically significant in this small subgroup.

Conclusions: We found a diagnostic yield of dCTM to be similar to the yield previously reported for digital subtraction myelography among patients with positive brain imaging. No CVFs were identified in patients with negative brain imaging; epidural CSF leaks accounted for all cases of patients who had SIH with negative brain imaging. This study provides useful data for counseling patients and helps establish a general benchmark for dCTM yield for CVF detection.ABBREVIATIONS: SIH = spontaneous intracranial hypotension; CVF = CSF-Venous Fistula; CTM = CT Myelography; dCTM = decubitus CT myelography; EBP = epidural blood patch.