Michael J. Zhang

Assessment of Coronary Plaque Presence and Composition by 320-Slice Cardiac Computed Tomography: A Comparative Study Using Intravascular Ultrasound

Background: Non-invasive determination of coronary plaque burden and composition may be important for the predictionof future cardiovascular events.Wedetermined the diagnostic accuracy of latest generation 320-slice CT angiography for thedetectionandcharacterisationof coronary plaque on a per-segment basis compared with gold standard intravascular ultrasound (IVUS). Methods: We analysed the datasets of 13 patients with suspected or known coronary artery disease who underwent both 320-slice CT with 350ms gantry rotation, 320mm× 0.5mmcollimation (AquilionOne, Toshiba Japan), 60–90mls contrast agent and IVUS (iLab, Boston Scientific USA) within a 4-week time period. Diagnostic image quality was achieved in all segments on CT. The arteries were divided into coronary segments using the AHA 17-segment coronary model referenced to fiduciary landmarks on both modalities. CT and IVUS studies were interpreted by independent blinded expert observers as computed tomography (MDCT) in assessing global LV function, and no data exists regarding its ability to assess LV regional wall motion (RWM). Methods: We evaluated 50 consecutive patients (mean age 60± 14 years, 66% male) who underwent 320-slice MDCT (dose-modulated retrospective electrocardiogram-triggering) and 2D-echocardiography within 30 days for investigation of known or suspected coronary disease. Two blinded cardiologists measured LV volumes on MDCT and visually assessed RWM with a 4-point scale using a 17-segment model. A separate experienced echocardiologist, blinded to MDCT findings, assessed LV RWM on 2D-echocardiograms and determined LV volumes and LV ejection fraction (LVEF) using the Simpson’s biplane method. 2D-echocardiography served as the reference standard. Results: Mean LVEF was 59± 8% (range 26–75%) on 2D-echocardiography and 60± 9% (range 27–76%) on MDCT. Using linear regression analysis, MDCT agreed very well with 2D-echocardiography for assessment of LVEDV (r= 0.94; P< 0.001), LVESV (r= 0.97; P< 0.001) and LVEF (r= 0.95; P< 0.001). Mean differences (±S.D.) of 14± 13ml, 5± 7ml and 1± 3% were observed between MDCT and 2D-echocardiography for LVEDV, LVESV and LVEF, respectively. 81/850 (9.5%) LV segments had abnormal RWM on 2D-echocardiography. Agreement for assessment of RWM between 2D-echocardiography and