In assessing the ICA, which characteristic would indicate hemodynamically significant stenosis?

Hemodynamically significant stenosis in the Internal Carotid Artery (ICA) is typically characterized by changes in blood flow dynamics. When there is stenosis, or narrowing, of the artery, the blood flow velocities often increase as the blood is forced through the restricted area.

A focal acceleration with increased systolic flow indicates that the blood is moving faster due to the narrowing caused by the stenosis. This acceleration occurs because as blood flows through the narrowed region, it accelerates to maintain flow continuity, resulting in elevated peak systolic velocities. This finding serves as a strong indicator of hemodynamically significant stenosis.

In contrast, other choices describe characteristics typically associated with normal or less severely affected vessels. Normal peak and end-diastolic velocities would suggest that there is no significant obstruction; low resistance waveform patterns can indicate adequate flow in vascular territories without significant stenosis; and consistent laminar flow suggests smooth, uninterrupted blood flow rather than the disturbed flow seen in the presence of stenosis. Thus, a focal acceleration with increased systolic flow is a critical finding used to evaluate the severity of stenosis in the ICA.