Doppler sonographic evaluation of shunts in patients with dural arteriovenous fistulas.

Background And Purpose: Doppler sonography has been used to assess global cerebral circulation time (CCT) in healthy volunteers and a small number of patients with cerebral arteriovenous malformations. We evaluated the effect of arteriovenous shunts on global CCT in patients with dural arteriovenous fistulas (DAVFs) by using this Doppler echo contrast-bolus tracking test.

Methods: We measured CCT as the time delay in a contrast bolus to the internal carotid artery (ICA) and internal jugular vein (IJV) in 13 patients with DAVF and 30 age-matched control subjects. Mean CCT and mean arterial and venous rise times (Delta t = 80% of total signal-intensity increase) were compared. Posttreatment follow-up measurements were performed in five patients.

Results: Mean CCT and venous Delta t were significantly different between patients and controls (CCT, 1.1 +/- 0.9 vs 6.9 +/- 1.2 seconds, P <.0001; venous Delta t, 5.2 +/- 2.0 vs 7.0 +/- 2.6 seconds, P =.024), but arterial Delta t values were not (4.4 +/- 1.8 vs 4.7 +/- 2.0 seconds). Posttreatment follow-up of two occluded fistulas showed CCT normalization. One near-occlusion showed a two-step increase in signal intensity, and incomplete occlusion in two patients left the CCT unchanged. One patient with an extracranial, highly vascularized glomus tumor draining into the IJV had a CCT of 1.8 seconds.

Conclusion: In DAVF patients, sonographic CCT is significantly shortened. Our test is highly sensitive for arteriovenous shunts but not specific for DAVF alone. Follow-up measurements in DAVF patients are well correlated with results of angiographic treatment. CCT assessment might become an additional tool for evaluating these patients and monitoring their treatment.