Feasibility of Noninvasive Assessment of Thin-Cap Fibroatheroma by Multidetector Computed Tomography

OBJECTIVES The purpose of this study was to investigate whether multidetector computed tomography (MDCT) can noninvasively help assess thin-cap fibroatheroma (TCFA). BACKGROUND Plaque rupture and thrombus formation play key roles in the onset of acute coronary syndrome. TCFA is recognized as a precursor lesion for plaque rupture, and MDCT angiography can potentially help identify plaques prone to rupture. METHODS We enrolled 105 patients with coronary artery disease (acute coronary syndromes, n = 31; stable angina pectoris, n = 74). Culprit lesions were assessed by both MDCT and optical coherence tomography (OCT). Patients were divided into a TCFA and a non-TCFA group according to OCT findings; clinical and MDCT observations were compared for 2 groups. RESULTS There were no differences in patients' characteristics between the 2 groups. OCT revealed 25 TCFAs at the culprit site in 105 patients. Acute coronary syndrome was more frequent in the TCFA group than in the non-TCFA group (52% vs. 23%, p = 0.01). High-sensitive C-reactive protein was higher in the TCFA group (0.32 +/- 0.32 mg/dl vs. 0.17 +/- 0.16 mg/dl, p < 0.001). Positive remodeling identified by MDCT was observed more frequently in the TCFA group than in the non-TCFA group (76% vs. 31%, p < 0.001). Computed tomography attenuation value of the culprit plaque in the TCFA group was lower than that in the non-TCFA group (35.1 +/- 32.3 HU vs. 62.0 +/- 33.6 HU, p < 0.001). The frequency of ring-like enhancement in the TCFA group was higher than in the non-TCFA group (44% vs. 4%, p < 0.0001). The sensitivity, specificity, positive predictive value, and negative predictive value of ring-like enhancement for detecting TCFA are 44%, 96%, 79%, and 85%, respectively. By stepwise regression, the ring-like enhancement, high-sensitive C-reactive protein, and diagnosis of acute events were associated with the presence of TCFA at the culprit site. CONCLUSIONS MDCT can identify differences in plaque morphologies between TCFA and non-TCFA. From our results, MDCT may provide for the noninvasive assessment of vulnerable plaque. (J Am Coll Cardiol Img 2009;2:1412-9) (C) 2009 by the American College of Cardiology Foundation