Intraplaque CTA characteristics as predictors of symptomatology: a semiautomated volumetric analysis

Background: Prior studies comparing CT characteristics of carotid plaques to symptomatology have relied on gross morphologic imaging features. This study sought to determine if volumetric measurements of carotid plaque components are associated with ipsilateral neurologic symptoms. Materials and methods: CTA images of consecutive patients that underwent a carotid endarterectomy were reviewed with a semiautomated software package. Intraplaque volumes of intraplaque hemorrhage (IPH), lipid-rich necrotic core (LRNC), and matrix were computed, as was the degree of arterial stenosis. Statistics were analyzed on a per cerebral hemisphere basis, and dichotomized into symptomatic and asymptomatic. Clinical and radiological endpoints included transient ischemic attack (TIA), ischemic stroke diagnosed on imaging studies, ophthalmologically diagnosed central or branch retinal artery occlusion (RAO), or amaurosis fugax. Results: One hundred sixty-eight carotid plaques were reviewed. The average age is 70.8 years (SD = 8.8); 32/87 (36.8%) were female. Sixty-seven of eighty-seven (77.0%) patients were symptomatic. Sixty-six of one hundred sixty-eight (39.3%) plaques were ipsilateral to the patient’s symptoms, while 102/168 (60.7%) were ipsilateral to an asymptomatic hemisphere. Greater intraplaque volumes of IPH (p = 0.03), LRNC (p = 0.008), and matrix (p = 0.0008) were associated with symptoms, as was greater proportion of LRNC in regard to plaque volume (p = 0.04). All but proportion of LRNC remained statistically significant after adjustment for plaque size. More severe luminal stenosis was also associated with ipsilateral neurologic symptoms, both when calculated by smallest diameter or by area (p < 0.0001 for both). Conclusion: Higher volumes of intraplaque IPH, LRNC, matrix, and degree of arterial stenosis are associated with ipsilateral neurologic symptoms. Greater intraplaque proportions of LRNC are also associated with ipsilateral ischemic manifestations, suggesting that larger relative composition of lipids may be particularly predictive of symptomatology.