Evaluation of the Factors Affecting the Diagnostic Performance of Coronary Computed Tomography Angiogram (CTA) With Multi-slice Computed Tomography (MSCT)

Purpose Prospectively evaluating the factors affecting the diagnostic accuracy of coronary CTA with multi-slice CT (including 64-slice CT and dual-source CT) in detecting coronary stenosis, in comparison with quantitative X-ray coronary angiography, to establish the standard of image quality and associated parameters to ensure accurate diagnosis of coronary stenosis with coronary CTA.

Detailed Description Over the past few years, the development in CT technology, especially the introduction of 64-slice multi-slice CT (64 MSCT), has permitted the application of coronary CT angiography to detect coronary stenosis in suspected patients with coronary heart diseases. Now, coronary CT angiography has been widely used worldwide. However, the accuracy of coronary CT angiography is always a concern in decision making of proper treatment, especially in determining the existence of significant stenosis in patients with visible coronary arteriosclerosis.

Factors affecting the diagnostic accuracy may include spatial resolution, temporal resolution, motion artifacts, banding artifacts, image noise level, calcification, vessel enhancement, operator dependant factors, etc. One or more factors may affect the diagnosis performance in any single case. So it is important to determine the weighting of these factors in stenosis detection and the tolerance of diagnostic accuracy to these adverse factors.

Materials and methods

1. Patient Population: About one thousand patients will be recruited over one year from our institution and other hospitals. All patients will undergo coronary CTA for suspected coronary artery disease. Then X-ray coronary angiography will be performed based on the impression on CTA findings from one radiologist (who will not participate the study) and/or clinical suspicion. Cases with both coronary CTA and X-ray coronary angiography in two weeks will be included. Our Institutional Review Board has approved the study. All patients will give informed consent. Patients with acute heart failure, severe arrhythmia and severe renal dysfunction will be excluded from cardiac studies.
2. To identify stenosis, the coronary arteries of all cases were divided into 15 segments for evaluation with coronary CTA and SCA. Coronary stenosis was recorded as percentage narrowing of lumen diameter and degree of stenosis (without stenosis, mild stenosis (≦50%), moderate stenosis (51%~75%), and severe stenosis (100%)). Experienced radiologists and cardiologists make the assessment independently in a double blind manner. The result of SCA was used as gold standard.
3. The process of coronary CTA examination of each recruited case will be carefully recorded to evaluate the factors that may affect the diagnostic performance of coronary CTA, such as heart rate, contrast injection parameters, delay time, optimal phase for reconstruction, etc. In addition, image quality will be evaluated, including the grading of motion artifact, banding artifact, enhancement, etc.
4. To evaluate operator dependant factors, all the reformations of coronary CTA will be performed by two different operators. The reformed images will also be reviewed by two different observers to evaluate the stenosis, as well as the image quality factors (motion artifacts, banding artifacts, image noise level, calcification burden, vessel enhancement).
5. Statistical analyses will be performed to evaluate the weighting of different factors in affecting the accuracy of coronary CTA.