Carotid sonography is a well-established technique in the evaluation of patients with neurologic symptoms. We describe the case of a woman in whom duplex Doppler sonography of the extracranial carotid circulation showed high-velocity diastolic flow and a low resistance index without turbulence or morphologic abnormality of the artery. A suspected cause of this finding was low-resistance distal circulation secondary to low-resistance intracranial circulation due to an arteriovenous malformation. This diagnosis was later confirmed by CT. Because of the significant risk of bleeding associated with an asymptomatic intracranial arteriovenous malformation, duplex Doppler sonographic findings suggesting a low-resistance waveform in the presence of a morphologically normal carotid artery should prompt further imaging.
Copyright 2002 Wiley Periodicals, Inc.