Evaluation of the Severity of Internal Carotid Artery Stenosis Using the Pulsatility Index of the Middle Cerebral Artery.

We evaluated the relationship between the grade of internal carotid artery (ICA) stenosis and the pulsatility index (PI) of the middle cerebral artery (MCA) . [Methods] PI and MCA mean velocity (Vm) values were obtained for 27 patients with ICA stenosis using transcranial Doppler sonography. The PI values were also obtained for 16 healthy volunteers (0.77±0.12) . The patients were divided into 3 groups (Group A (n=8) : PI<0.65; Group B (n=12) : 0.65≤PI<0.89; Group C (n=7) : 0.89≤PI) and the grades of ICA stenosis and the Vm values were compared among the three groups. [Results] There was a significant correlation between the grade of ICA stenosis and the PI (stenosis=112.5-39.3×PI, R=0.644, p=0.0003) . The grades of ICA stenosis in groups A (91.1±6.2%) and B (80.6±12.6%) were significantly greater than those in group C (67.9±9.1%) (p<0.05) . There was no significant correlation between Vm and PI. [Conclusions] There was a linear correlation between the grade of ICA stenosis and PI, suggesting that the grade of stenosis is greater in cases with lower PI.