Research Of Best Reconstruction Phase And Clinical Application Value Of Coronary Angiography With Dual-Source Computed Tomography

Objective:To investigate the relationship between the optimal reconstruction phase and heart rate and to determine the optimal systolic and diastolic reconstruction intervals for coronary CT angiography(CTA) using dual-source CT.And to evaluate the clinical value of coronary CTA in the detection of coronary artery disease.Materials and methods:1.Patients data:Two hundred and fifty-two patients(163 males and 89 females;mean age 57.30±6.76 years,rage 37～73 ) with suspected or diagnosed coronary artery disease(CHD) were studied using DSCT(dual-source computed tomography)from November 2007 to November 2008. And thirty-four patients underwent conventional coronary angiography.2.Scanning protocol:All the examinations were performed with DSCT(Dual-Source Computed Tomography),all patients underwent enhanced scan and the technique of Bolus tracking was applied.The scan range was from the trachea carina to 1～2cm under the musculus diaphragm3.Post-processing method:Raw data were reconstructed in 5% intervals throughout the R-R interval,and the best systolic phase and best diastolic phase phase were selected by computed.The axial images in different phases were reconstructed by the Circulation sofeware in the work station using maximum intensity projection,curved plannar reformation and volume rendering technique,etc.4.Evaluation method:4.1 The image quality of coronary artery was divided into five grades and the grade of every coronary artery in different reconstruction was evaluated.Two independent readers selected optimal systolic and diastolic reconstruction windows for each major coronary vessel.4.2 The degree of stenosis of coronary artery was divided into four groups:gentle (≤50%),moderate(51%～75%),severe(76%～99%) stenosis and occlusion(100%).5.Statistical assay:The data was analyzed using the software of SPSS11.0.p＜0.05 was taken to indicate statistical difference.Results:1.In most patients with a heart rate of＞80 bpm,the median optimal systolic reconstruction windows were at 35%,40%,40%and 35%for the RCA,LAD and CX(2.95±0.86 3.45±0.44 3.10±0.52 p＜0.O5);In patients with a heart rate of≤80bpm,The median optimal diastolic reconstruction window was at 75%for all vessels.2.The overall sensitivity,specificity,positive and negative predictive value for evaluating CAD were 91.42%,99.48%,94.11%,and 99.74%,respectively.Conclusion:1.In patients with heart rates of≤80bpm,the optimal reconstruction windows was at 75%of the R-R interval;In patients with heart rates of＞80 bpm,systolic reconstructions were selected to yield superior image quality.2.DSCT can provides high diagnostic accuracy for assessment of CAD. And it is a better choice for CAD evaluation.