Noninvasive detection and localization of vulnerable plaque and arterial thrombosis with computed tomography angiography/positron emission tomography.
BACKGROUND
It has been shown that plaque uptake of fluorodeoxyglucose is proportional to macrophage density. We tested the hypothesis that arterial thrombosis occurs in areas with high fluorodeoxyglucose uptake and that computed tomography angiography (CTA) can detect thrombi in vessels.


RESULTS
Twenty New Zealand White rabbits were studied before and after atherosclerosis induction through de-endothelialization and a high-cholesterol diet; 14 were then thrombus triggered. CTA/positron emission tomography scans were performed before cholesterol diet, at the middle diet feeding, at the end of diet feeding, and after triggering. Serum inflammatory markers were measured. Maximal standardized uptake value was measured over the thoracic and upper and lower abdominal aortas and correlated with thrombosis and macrophage density on sections from the same sites. Aortic diameters averaged 2.84+/-1.16 mm. The sensitivity, specificity, and accuracy of CTA for detecting thrombi were 92%, 89%, and 90%, respectively. Plasminogen activator inhibitor-1 and C-reactive protein levels increased with atherosclerosis and thrombosis triggering. Maximal standardized uptake value at baseline was 0.62+/-0.13, 0.96+/-0.33 at the middle of feeding, and 1.06+/-0.38 at the end of feeding. Segments that developed thrombosis had the highest maximal standardized uptake value of 1.32+/-0.69 (113% increase; P=0.002) and had a 129% increase in macrophage density compared with segments without thrombi (P=0.01).


CONCLUSIONS
Fluorodeoxyglucose uptake was proportional to the duration of cholesterol feeding and peaked with plaque disruption and thrombosis. CTA was highly accurate in detecting thrombi. Our findings in this animal model of atherosclerotic plaques with high macrophage density showed that CTA/positron emission tomography can be used to identify and localize inflamed plaques and thrombosis. With the currently available technology and nuclear tracers, however, many challenges remain before clinical applications are possible.
Aziz
Kusai
K
Department of Medicine, Division of Cardiology, Michigan State University, East Lansing, MI 48824, USA.
Berger
Kevin
K
Claycombe
Kate
K
Huang
Ruiping
R
Patel
Roshan
R
Abela
George S
GS
D000818:Animals; D001018:Aortic Diseases / Q000000981:diagnostic imaging / Q000276:immunology; D050197:Atherosclerosis / Q000000981:diagnostic imaging* / Q000276:immunology; D002097:C-Reactive Protein / Q000378:metabolism; D002791:Cholesterol, Dietary / Q000494:pharmacology; D019788:Fluorodeoxyglucose F18; D008264:Macrophages / Q000473:pathology; D008297:Male; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood; D049268:Positron-Emission Tomography / Q000379:methods; D011817:Rabbits; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D013927:Thrombosis / Q000000981:diagnostic imaging* / Q000276:immunology; D014057:Tomography, X-Ray Computed / Q000379:methods; D014657:Vasculitis / Q000000981:diagnostic imaging / Q000276:immunology
D002791:Cholesterol, Dietary; D017395:Plasminogen Activator Inhibitor 1; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D002097:C-Reactive Protein