During the last 2 months, your department has compared 94 in…

During the last 2 months, your department has compared 94 internal carotid arteries evaluated by carotid duplex with angiography. The results showed 50 vessels had a hemodynamically significant lesion by either method. 40 vessels had no lesion by either method. In 1 case, the noninvasive ultrasound was negative, but the angiogram showed a 70-99% diameter reduction.  In 3 cases, the noninvasive studies were consistent with a >50% diameter reduction, but the invasive study was read as normal. How accurate is your diagnostic facility in performing carotid duplex?

A 68-year-old male presents with dizziness and left arm weak…

A 68-year-old male presents with dizziness and left arm weakness during exertion. Blood pressure is 30 mmHg lower in the left arm compared to the right. On Doppler ultrasound, the left vertebral artery demonstrates a “bunny rabbit” waveform pattern with late systolic flow reversal. What is the most likely diagnosis?