Advantages
1. Non-invasive
2. Potentially more cost effective relative to traditional cardiac cath
Disadvantages
1. Significant radiation exposure - 7 to 21 mSv (depending on protocol) versus 2 - 5 mSv from an average diagnostic x-ray coronary angiogram
2. Certain patient-related factors can interfere with diagnostic quality of images ie. heart rate greater than 60 - 70 beats/min, irregular heart rhythm (atrial fibrillation or frequent extrasystoles), inability to sustain a breath hold for at least 15 - 20 secs
3. Severe coronary calcification or the presence of coronary stents can obscure the coronary artery lumen secondary to image reconstruction artifacts
4. Coronary artery segments with a diameter < 1.5 mm, typical of distal coronary artery segments and some side branches, are difficult to assess
5. Incidental radiological findings
6. While cardiac CT angiography has demonstrated reasonable sensitivity and specificity test characteristics in several trials, the broader applicability of these research center results has not been fully established
Source
Gerber, T. and Manning, W. "Noninvasive coronary angiography with cardiac computed tomography and cardiovascular magnetic resonance." Up to Date. 11 Feb 2009.