Imaging Ability Of 64-slice Spiral CT Coronary Angiography

Objective: With the technological development of multislice computed tomography (MSCT), MSCT has higher accuracy in diagnosis of coronary heart disease(CHD).Except the diagnostic value of MSCT for coronary artery stenosis, it has also been applied in assessment of obstructive bypass grafts and coronary stent patency. Now 64-slice spiral CT is available in many hospitals. Thus this study concerns three aspects about 64-slice spiral CT: 1. To evaluate the image quality of coronary angiography with 64-slice spiral CT, and analyze the factors affecting image quality 2. To evaluate the diagnostic accuracy for coronary artery stenosis with 64-slice spiral CT angiography 3. To evaluate coronary stent lumen patency with 64-slice spiral CT angiography.Methods: 1.Two hundred and fifty patients who were suspected of CHD or followed up after PCI (Percutaneous coronary interventions ) underwent MSCT(Siemens Sensation 64-slice CT) coronary angiography in the absence of contraindications. The image quality of reconstructed coronary artery segements was divided into five grades, and the first to the third grade was defined as evaluable . 250 images were used for evaluation. 2. 83 of all patients underwent invasive coronary angiography(CAG) within a week, meanwhile, 8 of all patients underwent intravascular ultrasound(IVUS). With CAG and IVUS as the reference standards,the artery stenosis≧50% was defined as positive result. Then we evaluated the diagnostic accuracy of 64-slice CT. 3. Evaluate coronary in-stent restenosis with 64-slice CT and CAG in 12 patients who had accepted coronary artery stenting theraphy. Radiologists and cardiologists obtained double-blinded results independently.Results: 1. The image quality of coronary angiography with 64-slice spiral CT: 2465 of the total 2823 coronary artery segments in 250 patients can be evaluated, which accounted for 87.3%. The proximal coronary artery segements accounted for more than 95% while distal coronary artery segements accounted for 60%～90%. The image quality of branch coronary artery segements was poorest. 2. Diagnostic accuracy for coronary artery stenosis with 64-slice spiral CT: The diagnosis sensitivity of coronary artery stenosis with 64-slice spiral CT was 85.7%, specificity was 94.8%, positive predictive value was 80.3%, negetive predictive value was 96.4%, and accuracy was 93.0%. Accuracy of proximal coronary arteries was 95% approximately, which was obviously higher than that of branch coronary arteries. 3. Evaluation of in-stent restenosis: 16 of the total 19 stents had been evaluated correctly, so the accuracy accounted for 84.2%. However, 64-slice CT will neglect some restenoses, in which the loss of the coronary stent lumen was less than 75%. 4. Factors of affecting image quality involved tachycardia, arrhythmia, respiration, calcification, scanning technology, reconstruction methods, and so on.Conclusion: 64-slice spiral CT coronary angiography is a reliable diagnostic method for CHD. It could also be used to assess in-stent restenosis . With the development of 256-slice CT and dual source CT, MSCT maybe have the similar value as CAG.