Kranz PG, et al. - The study is performed to depict the anatomic and imaging features of cerebrospinal fluid (CSF) venous fistulas, which are a recently revealed reason for spontaneous intracranial hypotension (SIH). The outcome of this study suggests that the CSF venous fistulas are an imperative cause of SIH that can be detected on both CT myelography (CTM) and dynamic myelography and may occur without an epidural CSF leak. Familiarity with the imaging qualities of these lesions is critical to providing appropriate treatment to patients with SIH.

Methods

• For this study, they retrospectively reviewed the records of patients with SIH caused by CSF venous fistulas who received treatment at their institution.
• They recorded anatomic details of each fistula.
• In this study, attenuation of the veins involved by the fistula was compared with that of adjacent control veins on CT myelography (CTM).
• Visibility of the CSF venous fistula on CTM and a modified conventional myelography technique they refer to as dynamic myelography was also compared.

Results

• They identified total twenty-two cases of CSF venous fistula.
• The fistulas were situated amongst T4 and L1. 90% occurred without a concurrent epidural CSF leak.
• The CSF venous fistula originated from a nerve root sleeve diverticulum in most cases (82%).
• On CTM, the abnormal veins related to the CSF venous fistula were found in a paravertebral location in 45% of cases, centrally within the epidural venous plexus in 32%, and lateral to the spine in 23%.
• Differences in attenuation between the fistula veins and the control veins was highly statistically significant (p < 0.0001), with a threshold of 70 HU perfectly discriminating fistulas from normal veins in this series.
• When both CTM and dynamic myelography were performed, the fistula was identified on both modalities in 88% of cases.