Abstract
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. 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. 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. 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.
Highlights
BACKGROUND AND PURPOSEThe purpose of this study was to evaluate the sensitivity and specificity of renal/ureteric opacification on postmyelographic CT as a sign of 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
Summary
An approval from the institutional review board at the Washington University in Saint Louis was obtained for this Health Insurance Portability and Accountability Act–compliant retrospective case-control research project. The objective measurement of the collecting system the Schievink diagnostic criteria A or B, with none seen in Hounsfield unit further adds validity to this finding and can, in patients meeting criterion C This finding was similar to that of combination with the visual assessment, serve as an additional Kinsman et al because their study showed contrast opacification sign of CSF leak. While arguing for measuring Hounsfield units of the renal pelvises, it suggests the possible role of techniques such as dualenergy CT myelography in bringing out these inherent subtle contrast differences.[20,21] Recognition of this sign has important implications in the management of patients with suspected ICH. Our results suggest that recognition of renal contrast on CT myelography should prompt a thorough review of CT myelography for subtle signs of CSF leak, and if not found, an active pursuit with additional imaging, including digital subtraction myelography to look for underlying pathology including a CVF or focal dural tear, should be performed.[8,10,22]
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