ISSN 1305-3825 | E-ISSN 1305-3612
Neuroradiology - Original Article
Prevalence of hyperdense paraspinal vein sign in patients with spontaneous intracranial hypotension without dural CSF leak on standard CT myelography
1 Department of Radiology, Mayo Clinic, Rochester, MN, USA  
2 Department of Neurology, Mayo Clinic, Rochester, MN, USA  
Diagn Interv Radiol ; : -

Abstract

PURPOSE: A recently identified and treatable cause of spontaneous intracranial hypotension (SIH) is CSF-venous fistula (CVF), and a recently described CT myelogram (CTM) finding highly compatible with but not diagnostic of this entity is the hyperdense paraspinal vein sign. Our goal was to retrospectively measure the prevalence of the hyperdense paraspinal vein sign on CTMs in SIH patients without dural CSF leak, in comparison to control groups.

 

METHODS: Three CTM groups were identified: 1) SIH Study Group: dural CSF leak-negative standard CTMs performed for SIH, with early and delayed imaging; 2) Control CTMs: performed for indications other than SIH, with imaging shortly after intrathecal contrast administration; 3) Control CTMs: included delayed imaging. CTMs were retrospectively reviewed for the hyperdense paraspinal vein sign by experienced neuroradiologists, blinded to the group assignment. All CTMs deemed by a single reader to be positive for the hyperdense paraspinal vein sign were independently reviewed by two additional neuroradiologists; only if consensus was present among all three readers were the findings considered positive. For positive cases, noncontrast CTs and prior CTMs, if available, were reviewed for the presence of the sign.

 

RESULTS: Seven of 101 (7%) SIH patients had contrast in a spinal/paraspinal vein consistent with the hyperdense paraspinal vein sign; no patient in either control group (total n=54) demonstrated the hyperdense paraspinal vein sign (p=0.0463). The finding occurred only at thoracic levels. Each patient had a single level of involvement. Six (86%) occurred on the right. Four occurred in female patients (57%). The sign was seen on early images in 3 of 7 cases (43%) and on both early and delayed images in 4 of 7 cases (57%). In two of the 7 (29%) patients, a noncontrast CT covering the relevant location was available and negative for the sign. A prior CTM was available in two of the 7 patients (29%), and in both cases the hyperdense paraspinal vein sign was also evident.

 

CONCLUSIONS: The prevalence of the hyperdense paraspinal vein sign in SIH patients with dural CSF leak-negative standard CTM was 7%. As the sign was not seen in control groups, this sign is highly compatible with the presence of CVF. Since the CTMs were not specifically dedicated to identifying hyperdense paraspinal veins (i.e. were not dynamic and were not preceded by digital subtraction myelography), the true prevalence of the sign may be higher. Radiologists should scrutinize conventional CTMs for this sign, especially in patients in whom a traditional dural CSF leak is not identified.

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