頚動脈プラークの病理組織学的所見と超音波所見

抄録

We reviewed the correlation of histological changes in aherosclerotic carotid arteries and images obtained by in vivo B-mode ultrasonography, based on pathoanatomical studies of carotid arteries obtained at autopsy and carotid endarterectomy specimens in relation to ultrasonographic findings. The crucial purpose of ultrasonography is to detect carotid plaques that pose a risk of ischemic cerebrovascular accidents. Our experience and review of the literature showed that carotid plaques carrying a risk of stroke are characterized by large dimension with severe luminal stenosis, ulcer formation, a large amount of stored lipid, intraplaque hemorrhage and a fragile fibrous cap over a fatty core.
By ultrasonography, fibrous plaque appears as localized thickening of the wall with little change in echogenicity. Fatty cores appear less echogenic than the adjacent tissue. Intraplaque hemorrhages also appear less echogenic, and therefore it is difficult to differentiate them from fatty cores. Calcified foci in plaques are highly echogenic and associated with acoustic shadowing. Ultrasonography cannot detect the detailed morphology of fibrous caps consistently. Plaques carrying a risk of stroke appear heterogeneous by ultrasonography. Even though its function is limited, B-mode ultrasonography is a unique technique for detecting the structural changes which cannot be revealed by angiography.