Usability of Ultrasonic MicroPure Imaging for Evaluating the Vulnerability of Carotid Atherosclerotic Plaques

Objective: MicroPure is an ultrasound imaging technology used for detecting microcalcifications. This study aimed to evaluate the usefulness of the Firefly sign in ultrasonic MicroPure imaging for detecting the vulnerability of carotid plaques.

Methods: Ultrasonic grey-scale imaging was used to detect carotid plaques. Ultrasonic MicroPure imaging was used to detect the Firefly sign and to determine the location and number of Firefly signs.

Results: A total of 142 plaques were detected in 72 patients, and 62.0% were Firefly-positive plaques. The length or thickness, the risk of rupture and the percentage of vulnerable plaques were greater in the Firefly-positive plaques than in Firefly-negative plaques. The assessment of plaque vulnerability built on the 4-point Firefly scoring system showed that the area under the ROC curve was 0.750 (P < .001). The sensitivity and specificity of vulnerable plaques with a score of 2 points were 71.9 and 73.6%, respectively.

Conclusion: The Firefly signs are widely present in carotid atherosclerotic plaques and can be detected with ultrasonic MicroPure imaging. Firefly signs located in fibrous caps may be associated with plaque vulnerability.