Fig. 5

A 76-year-old man with symptomatic internal carotid artery stenosis. Diffusion-weighted imaging (A) and FLAIR (B) showed findings consistent with a minor stroke. Preoperative SPECT revealed decreased cerebral blood flow (CBF) on the affected side (C: 41.6 mL/100 g/min), with a CBF asymmetry index (CBF-AI) of 0.79 and a cerebrovascular reserve (CVR) of 3% (D). Digital subtraction angiography (DSA) demonstrated a minimum luminal diameter of 1.41 mm preoperatively (E). Pressure recordings showed a clear pressure gradient between the proximal (red arrow) and distal (blue arrow) segments of the stenosis, with a carotid pressure ratio (CPR) of 0.73. After carotid artery stenting, DSA (F) showed improvement of the stenosis to 3.6 mm, and the pressure gradient disappeared, with the CPR improving to 1.02.