The application of ultrasound B-flow imaging in detection of carotid atherosclerotic micro-vessel with ischemic cerebrovascular disease

OBJECTIVE: To investigate the detection and characterization of micro-vessels within the carotid atherosclerotic plaque using B-flow imaging (BFI) ultrasound with contrast-enhanced ultrasound (CEU) as the reference standard.

METHODS: Between August 2008 and July 2011, 78 patients with carotid atherosclerosis that were admitted at the Department of Ultrasonography in ZhongNan Hospital of Wuhan University, Wuhan, China underwent standard and BFI examination. Fifty-one patients received both BFI and CEU. We evaluated the relationship between BFI findings, and clinical symptoms in ischemic stroke, or transient ischemic attack patients. The correlation of cerebrovascular symptoms, stenosis, and plaque type on the detection of neovessels by BFI were statistically evaluated using X2 test (McNemar test). The agreement of the 2 sonographic methods was assessed by K coefficient. The diagnostic efficacy of BFI for carotid atherosclerotic micro-vessel detection was also calculated.

RESULTS: The BFI findings of micro-vessel were correlated to patient's symptom. The agreement between BFI and CEU for diagnosis of microvascularization was good (K=0.406). The following was calculated: sensitivity (0.483); specificity (0.955); positive predictive value (0.933); negative predictive value (0.583); and accuracy of BFI (0.686). Logistic regression demonstrated a significant association between cerebrovascular events and the presence of BFI signals within carotid plaques (B: 2.422; 95% confidence interval: 1.728-73.407).

CONCLUSION: Compared with CEU, the BFI is less sensitive, however, it is a valid and practical method for detection of carotid atherosclerotic micro-vessels.