Usefulness of end-diastolic ratio in carotid ultrasonography for the screening of dural arteriovenous fistula: a case series.

We report three cases in which carotid ultrasonography was useful for the diagnosis of dural arteriovenous fistula (dAVF). In all cases, dAVFs were fed by branches of the external carotid artery (ECA) and had retrograde leptomeningeal venous drainage. Carotid ultrasonography revealed high end-diastolic ratio (ED ratio) of the common carotid artery (CCA) (1.49-2.16) and low resistance index (RI) of the ECA (0.59-0.66). They were normalized after endovascular treatment (ED ratio of CCA 1.02-1.06, RI of ECA 0.75-0.87). In conclusion, high ED ratio of the CCA and low RI of the ECA might be a useful indicator for both screening and follow-up of dAVF.