Patient With Left Carotid String Sign Demonstrating Baseline Perfusion Deficit of the Left Hemisphere That Becomes Dramatically Worse With Diamox
The right hemisphere also demonstrates decreased perfusion with diamox. These findings indicate inadequacy of the collateral circulation to the left hemisphere as well as cerebrovascular steal compromising right hemisphere perfusion during maximal vasodilation. After stenting of the left carotid, perfusion is dramatically improved at baseline and during stress. PTCA = percutaneous transluminal carotid angioplasty.