Assessment of neovascularization within carotid plaques in patients with ischemic stroke

To assess neovascularization within human carotid atherosclerotic soft plaques in patients with ischemic stroke.

Eighty-one patients with ischemic stroke and 95 patients without stroke who had soft atherosclerotic plaques in the internal carotid artery were studied. The thickest soft plaque in each patient was examined using contrast-enhanced ultrasound. Time-intensity curves were collected from 5 s to 3 min after contrast injection. The neovascularization within the plaques in the internal carotid artery was evaluated using the ACQ software built into the scanner by 2 of the experienced investigators who were blinded to the clinical history of the patients.

Ischemic stroke was present in 7 of 33 patients (21%) with grade I plaque, in 14 of 51 patients (28%) with grade II plaque, in 26 of 43 patients (61%) with grade III plaque, and in 34 of 49 patients (69%) with grade IV plaque (P < 0.001 comparing grade IV plaque with grade I plaque and with grade II plaque and P = 0.001 comparing grade III plaque with grade I plaque and with grade II plaque). Analysis of the time intensity curves revealed that patients with ischemic stroke had a significantly higher intensity of enhancement (IE) than those without ischemic stroke (P < 0.01). The wash-in time (WT) of plaque was significantly shorter in stroke patients (P < 0.05). The sensitivity and specificity for IE in the plaque were 82% and 80%, respectively, and for WT were 68% and 74%, respectively. There was no significant difference in the peak intensity or time to peak between the 2 groups.

This study shows that the higher the grade of plaque enhancement, the higher the risk of ischemic stroke. The data suggest that the presence of neovascularization is a marker for unstable plaque.