Is CTA or MRA better to assess for subclavian steal syndrome?
Subclavian steal syndrome is a clinical diagnosis. This syndrome occurs in the setting of a high grade stenosis or occlusion of the subclavian artery proximal to the origin of the vertebral artery, most commonly on the left side. In this situation, there is reversal of blood flow in the ipsilateral vertebral artery, diverting blood flow from the posterior circulation of the brain to the upper extremity. As such, the patient experiences symptoms, such as syncope, from reduced blood flow in the vertebrobasilar arterial system.
CTA and MRA can both depict stenosis or occlusion of the proximal subclavian artery. TOF MRA can also demonstrate a characteristic reversal of the direction of blood flow in the ipsilateral vertebral artery
