Abstract
Abstract: :
Purpose: To evaluate the usefulness of CTA as a non–invasive alternative to angiography for the diagnosis of high and low flow arterio–venous shunts of the cavernous sinus. Methods: Retrospective chart review examining sixteen patients with angiographically proven high and low flow arterial–venous shunts involving the cavernous sinus. In all patients, CTA was performed on a GE Lightspeed Scanner using 125cc of non–ionic contrast injected intravenously at 5cc/sec. The results of CTA regarding the identification of a flow nidus, determination of extent of the lesion (unilateral/bilateral/vessels involved), and identification of the presence of cortical–venous drainage were compared to subsequent findings of traditional 4–vessel cerebral angiography. Secondary signs including enlargement of the superior ophthalmic vein, asymmetric filling of the sinus and/or abnormally engorged vessels were judged presumptive evidence of fistula even if a nidus was not clearly identified. Results: In high flow fistulas CTA sensitivity was 100% and had a high correlation with angiography for the extent of the lesion, presence of cortical–venous drainage, and location and morphology of the nidus. In low flow fistulas CTA identified all patients with retrograde cortical–venous drainage. In the remainder of low–flow fistulas, if the nidus was difficult to identify, secondary signs were present on CTA that lead to ultimate confirmation by angiography. In one patient presumptive signs on CTA were falsely positive. Conclusions: CTA is accurate and sensitive for detection and delineation of high flow cavernous sinus lesions and indirect signs are usually present in low flow lesions. Therefore, CTA is a sensitive and non–invasive diagnostic test prior to angiography. However, patients with a high clinical suspicion and negative CTA require traditional cerebral angiography.
Keywords: neuro–ophthalmology: diagnosis • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)