s3-2 Tissue Characterization of Carotid Artery Plaque by Ultrasonography

It has been reported that plaques are lipid-rich (unstable) or fibrotic (stable). 32 patients undergoing carotid endarterectomy were examined by ultrasonography (SONOS5500) with a linear 7.5 MHz probe preoperatively and IBS (integrated back scatter) values of carotid plaques were measured. Then the ultrasonic tissue characterization findings were compared to those of optical microscopy of the removed specimens. IBS values of intimal-medial layer were significantly lower in lipid-rich plaque (n=19, 7.3±3. 6dB) and intraplaque hemorrhage (n=10, -12.1+3.4 dB) than those in fibrous tissue (n=10, -3.2+3.3dB) and hyaline tissue (n= 13, 17.0±4.1dB). We measured IBS values of carotid plaques in 204 patients. IBS values were significantly lower in patients with atherothrombotic cerebral infaretions (n=13, -6.9+5.4dB), isehemic heart disease (n=-28, -2. 4±5. 5dB) and acute coronary syndrome (n=21, -3.1±5.8dB) than those in normal layer (n=60, 0.0±3.6dB). Presences of low HDL cholesterolemia, hyperlipemia and diabetes mellitus decrease IBS values of carotid plaques. It is possible to evaluate tissue characterization of carotid plaques by measuring IBS values using ultrasonography.