Value of carotid intima thickness in assessing advanced carotid plaque vulnerability: a study based on carotid artery ultrasonography and carotid plaque histology

Background: Research has shown that carotid intima-media thickness (CIMT) could help to predict carotid plaque (CP) progression in patients with mild carotid stenosis. However, the debate continues as to the value of carotid intima thickness (CIT) in monitoring the development of CP in patients with severe carotid stenosis. This study sought to evaluate the relationships between CIT and the ultrasonic characteristics of CP and to analyze the value of CIT and the ultrasonic parameters of CP in assessing plaque vulnerability in advanced human carotid atherosclerosis. Methods: A total of 55 individuals who underwent carotid endarterectomy (CEA) were included in the study (mean age: 65 +/- 7 years; female: 9.1%). CIMT and CIT were examined at the common carotid artery (CCA). Plaque textural features, such as the gray -scale median (GSM), superb microvascular imaging (SMI) level, and total plaque area (TPA), were also identified. A Spearman correlation coefficient analysis was performed to examine the relationship between CIT and the ultrasonic parameters of CP. The CIT of various plaque types was compared. Receiver operating characteristic (ROC) curves were used to analyze the diagnostic values of the ultrasound characteristics to evaluate CP vulnerability. Results: The mean CIT of all the participants was 0.382 +/- 0.095 mm, the mean CIT of the participants with stable plaques was 0.328 +/- 0.031 mm, and the mean CIT of participants with vulnerable plaques was 0.424 +/- 0.106 mm (P<0.001). CIT was associated with the SMI level (Spearman's correlation coefficient: r=0.392, P=0.005), TPA (Spearman's correlation coefficient: r=0.337, P=0.012). Patients with thicker CIT had larger lipid cores, higher levels of plaque vulnerability, and more intraplaque hemorrhages (IPHs). The areas under the ROCs (AUCs) with 95% confidence interval (CI) for CIMT, CIT, the SMI level, the GSM, the TPA, and the combined model for identifying vulnerable plaques were 0.673 (0.533-0.793), 0.849 (0.727-0.932), 0.771 (0.629-0.879), 0.669 (0.529-0.790), 0.858 (0.738-0.938), and 0.949 (0.854-0.990), respectively. Conclusions: CIT was associated with both the histology and ultrasonic features of CP. CIT may be helpful in the detection of severe CP development.