Efficacy of Orbital Color Doppler Imaging and Neuroimaging in the Diagnosis of Carotid Cavernous Fistulas

Purpose: To evaluate the diagnostic sensitivity and specificity of orbital color Doppler imaging (CDI) and conventional neuroimaging (CT/MRI) compared with cerebral angiography in patients with carotid-cavernous fistulas (CCFs). Methods: The study design was a retrospective patient chart and imaging review. The authors reviewed 655 charts of all patients who underwent CDI and neuroimaging (CT/MRI) between 2006 and 2015 at one institution. Sixty patients had a presumptive diagnosis of CCF without thrombosis. Thirty-seven patients with 43 events met the inclusion criteria of the study. The diagnostic sensitivity of the 3 noninvasive imaging modalities (CDI, CT, MRI) for CCF was compared with the gold standard 6-vessel cerebral angiography. Significance testing was performed using the 2-tailed Fisher test. Results: Color Doppler imaging had high sensitivity (96.8%) but low specificity (41.7%) for the diagnosis of CCFs with anterior orbital findings. A negative CDI had more diagnostic value than a positive CDI. While an arterial wave form in the superior ophthalmic vein was the most common finding of CCF on CDI, enlargement of the superior ophthalmic vein was the only statistically significant finding. Posterior cortical venous drainage was noted in about 10% of the patients with indirect (low-flow) fistulas, who presented with unilateral orbital signs and symptoms, a finding not previously reported in the literature. Conclusion: Color Doppler imaging is a useful noninvasive, radiation-free modality for diagnosis of CCF with anterior drainage, with higher sensitivity than CT or MRI, but equivalent specificity. A significant limitation of CDI is the lack of usefulness in diagnosing fistulas with posterior cortical venous drainage, which carry a risk of intracerebral hemorrhage and stroke. In this series, 10% of unilateral CCFs with anterior orbital signs and symptoms showed angiographic evidence of posterior cortical venous drainage.

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