Objective To evaluate the diagnostic value of 64-row VCT coronary angiography(CTA) in diagnosing coronary artery disease.Methods 64-row VCT coronary angiography(CTA) and cathter coronary angiography(CAG) were performed in 173 patients with suspected coronary artery disease.All images were analysed at GE AW4.3 workstation,the constructed images included maximum intensity projection(MIP),mlti-planar reconstruction(MPR) and volume rendering(VR).The results were compared with that of CAG.Results 746 segments of coronary artery with diameter ＞1.5 mm were showed by CTA in 173 patients.The sensitivity,specificity,positive predictive value and negative predictive value of the CTA in detecting coronary arterial stenosis were 94.15%(193/203),95.90% and 89.77% and 97.90% respectively.Statistical analysis using a 2-related χ~2 test showed that there were no obvious differences in diagnosing coronary arterial stenosis between CTA and CAG(χ~2=1.58,P＞0.05) and in evaluating the stenosis degree of coronary artery(Kappa=0.890,P＜0.001).Conclusion 64-row VCT has important clinical value in screening coronary arterial disease and in following-up post operational effectiveness of coronary stent implantation and vascular bypass.

Ojective To investigate the clinical application value of low dose contrast agent in computerized tomography pulmonary angiography (CTPA) with spectral CT imaging.Methods Totally 52 patients suspected with pulmonary embolism underwent multi-slice spiral CT pulmonary angiography,and were randomly divided into a control group (n =27) and a research group (n=25).The research group used spectral CT with 35 ml of contrast medium and the control group used 64-slice CT with conventional 80 to 90 ml of contrast medium.The CT values of the pulmonary trunk,left pulmonary artery (LPA),right pulmonary artery (RPA),pulmonary vein and ascending aorta were measured.The contrast to noise ratio (CNR) of the pulmonary artery was also calculated.In addition,the image quality of CTPA was evaluated independently by two experienced radiologists.Results The CT values (HU) of the pulmonary trunk,left pulmonary artery(LPA),right pulmonary artery (RPA) in the research group were (432.2±63.4),(373.5±48.8),(381.4±53.6) and (62.5-±6.4),respectively,and significantly higher than those in the control group,showing statistical differences (P＜0.05).The evaluation results of the CTPA images by two radiologists showed that the image quality in the research group was better than that in the control group (P＜0.05).Conclusion The image quality of pulmonary angiography with spectral CT using low contrast medium dose can be improved compared with the conventional spiral CT.