Circ J 2009; 73: 772 -775 s an alternative to invasive coronary angiography (CAG) or intravascular ultrasound (IVUS), noninvasive 64-slice multidetector row computed tomography (MDCT: 64×0.625 mm collimation) with retrospective ECG-gated image reconstruction permits coronary artery visualization and the detection of coronary artery stenoses with high accuracy. 1,2 Additionally, because not only the vessel lumen but the vessel wall and adjacent tissue can be visualized by this modality, MDCT might be useful for characterizing coronary plaque morphology by determining its tissue density 3-6 and for assessment of coronary remodeling. 7 We propose a new method, Color Code Plaque TM (CCP) analysis (GE Healthcare, Waukesha, WI), which analyzes each pixel value of the computed tomography (CT) images as opposed to the conventional region of interest. CCP measures the CT number of plaque for each pixel, and codes them with several color ranges that can be easily modified by changing the CT number criteria.
Case ReportA 61-year-old woman with hypercholesterolemia, hypertension and diabetes mellitus was referred to hospital for the evaluation of chest pain at rest. At the first medical examination, she was treated with amlodipine 5 mg/day, nicorandil 15 mg/day and pravastatin 10 mg/day.MDCT (VCT; GE Healthcare, detector collimation 64×0.625 mm, 035 s/rotation) was performed to evaluate the coronary artery disease and the field-of-view was set to 186 mm with a matrix of 512×512 (0.36×0.36 mm/pixel). An approximately eccentric 50% stenosis in the proximal right coronary artery (RCA) was detected in the volumerendering image and multiplanar reconstructions (MPR) (Figures 1A,B). At the 3 sites of maximal stenosis, distal and proximal 2 mm apart, cross-sectional MPR images were acquired ( Figure 1D Left) and CCP analysis was also done at those sites ( Figures 1C,D Right).The color patterns of CCP were easily modified to our preset color codes by changing the CT number (soft plaque: yellow to emerald-green -40-50 HU; intermediate plaque: blue 50-120 HU; enhanced vessel lumen: transparent 120-500 HU; calcified plaque: red 500-2,000 HU) according to Schroeder's criteria. 5 Approximately two-thirds of the plaque burden was light-green (0-25 HU) and one-third was yellow (-40-0 HU) at these sites. We diagnosed this plaque as soft (yellow to emerald-green code) according to our original CCP pattern.Seven days after MDCT, chest pain was triggered accidentally during echocardiography, continued for approximately 5 min and transient ST-elevation was apparent on the II-lead ECG monitor. Therefore, acute coronary syndrome (ACS) was considered and emergency CAG was performed, which revealed the approximately 50% stenosis in the proximal RCA (Figure 2), as on MDCT. Her disease (Received April 8, 2008; revised manuscript received May 27, 2008; accepted June 9, 2008; released online December 15, 2008 A 61-year-old woman with hypercholesterolemia, hypertension and diabetes mellitus was referred to hospital for the evaluation of chest pain ...