Behbahani S, Raseman J, Orlowski H, Sharma A, Eldaya R. Renal Excretion of Contrast on CT Myelography: A Specific Marker of CSF Leak.
AJNR Am J Neuroradiol 2020;
41:351-356. [PMID:
31974082 DOI:
10.3174/ajnr.a6393]
[Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 12/09/2019] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE
The purpose of this study was to evaluate the sensitivity and specificity of renal/ureteric opacification on postmyelographic CT as a sign of CSF leak.
MATERIALS AND METHODS
We performed a retrospective review of postmyelographic CT scans from 49 consecutive patients seen between January 2008 and August 2018 with imaging and/or clinical findings related to intracranial hypotension. Each scan was evaluated by both a neuroradiology fellow and a board-certified neuroradiologist for the presence of contrast in the renal excretory system. A similar assessment was also performed on 90 consecutive control subjects who underwent CT myelography for alternative indications.
RESULTS
Among the 49 patients with suspected CSF leak, 21 (43%) had an overt CSF leak on postmyelographic CT (group 1) and 28 (57%) did not (group 2). Overall, renal contrast was identified in 7/49 patients (14.3%): 5 (24%) patients in group 1, and 2 (7%) patients in group 2. Renal contrast was not seen in any of the 90 controls on postmyelographic CT.
CONCLUSIONS
Renal contrast was exclusively seen in patients with a clinically or radiographically suspected CSF leak. Given its 100% specificity, identification of this finding should prompt a second look for subtle myelographic contrast extravasation or an underlying CSF-venous fistula. Our results suggest that this sign may be considered an additional diagnostic criterion for CSF leak in the absence of an identifiable leak.
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