Abstract 3405: The Reliability of Multislice Computed Tomography in Differentiating Plaque Composition in Comparison With Histopathological Examination of the Atheromatous Tissue Obtained by Directional Coronary Atherectomy
Background: Several studies have reported that multislice computed tomography (MSCT) might be useful for non-invasive characterization of plaque composition in patients with coronary artery disease. In these studies, intravascular ultrasound (IVUS) findings were generally used as a standard of reference. However, the histopathological assessment for the efficacy of MSCT to differentiate atherosclerotic coronary plaque composition has not yet been reported in living body.
Methods: Forty-four target lesions in 44 patients with coronary artery disease (acute coronary syndrome (ACS): 22 patients, non-ACS: 22 patients), who underwent preintervention 16-detector MSCT and IVUS, and were treated with directional coronary atherectomy (DCA), were investigated. The lesions with severe calcifications unsuitable for DCA were excluded. DCA samples obtained from target lesions were stained with Hematoxylin-eosin, Masson-trichrome, Von-kossa, and immuno-histochemical methods: CD 68 against macrophages. Plaques were histopathologically classified into one of 3 groups; lipid rich plaque (L), fibrous plaque (F), and plaque with mild calcifications (MC). Mean CT density (MCTD) of the plaque was obtained by calculating MCTD from 3 sequential cross-sectional images at the lesion treated by DCA.
Results: MCTD was significantly different between lesions with ACS and non-ACS (76±47 in ACS vs. 126±74 in non-ACS, p<0.05). In ACS, 9 lesions were histopathologically classified into (L), 5 lesions into (F), and 8 lesions into (MC). MCTD were significantly different among these 3 groups (L: 45±10, F: 60±10, MC: 121±53, respectively, p<0.05). In non-ACS, 2 lesions were histopathologically classified into (L), 6 lesions into (F), and 14 lesions into (MC). MCTD in each group was also significantly different (L: 31±7, F: 86±29, MC: 157±73, respectively, p<0.01). MCTD in both (F) and (MC) plaques tended to be higher in non-ACS than in ACS.
Conclusion: Histopathologically determined lipid rich plaque obtained from coronary lesions in vivo showed lower CT density. The present study suggested that MSCT reliably and noninvasively differentiated atherosclerotic plaque composition both in ACS and non-ACS lesions.