Abstract 3407: Dual Energy 64-slice Multi-Detector Spiral Computed Tomography and Optical Coherence Tomography for the Identification and Characterization of Atherosclerotic Plaques in Isolated Human Coronary Arteries from Explanted Hearts
Multi-detector CT (MDCT) has been shown to permit visualization of the coronary arteries and detection of coronary artery stenoses. Some data also indicate the methods potential to identify and characterize coronary artery atherosclerotic plaques. To assess the ability and accuracy of contrast-enhanced 64-slice MDCT for the detection and definition of coronary artery plaques we analyzed isolated human coronary arteries from explanted hearts in direct comparison to optical coherence tomography (OCT).
Methods: Seven isolated human coronary arteries from explanted hearts (4 patients, 45 – 64 years) were mounted in a water-filled phantom. The arteries were constantly perfused with saline. OCT (Light Lab Imaging, Boston, USA) was performed using 5 frames per second and an automatic pullback of 1.0 mm/second. Following OCT, the arteries were investigated by contrast-enhanced (constant perfusion with diluted contrast agent using a concentration of 20 mg iodine/ml and a flow rate of 1 ml/s) 64-slice MDCT (Siemens Sensation 64, Forchheim, Germany) was performed with a gantry rotation of 0.33 s, a collimation of 64 x 0.6 mm and a pitch of 0.45. For better differentiation of atherosclerotic plaques types a low (110 mAs) and and a high energy (900 mAs) scan was performed, both using a tube current of 120 kV. Images were reconstructed with a slice thickness of 0.75 mm and 0.5 mm increment using medium sharp and sharp kernels. The identified coronary artery plaques were than visually differentiated in calcified, fibrous and lipid-rich.
Results: Using OCT as the gold standard 89% (17/19) of the plaques were identified by MDCT. Only 2 small, lipid-rich plaques were missed by MDCT. Concerning visual plaque characterization MDCT demonstrated an accuracy of 71%( 12/17). Thereby all calcified plaques (n = 8) were correctly classified by MDCT, whereas 1 fibrous plaques and 3 lipid-rich plaques were misinterpreted by MDCT.
Conclusion: In an ex-vivo study, 64-slice MDCT demonstrated a high sensitivity for the detection of coronary artery plaques, but limited accuracy for plaque characterization compared to OCT.