الفهرس 
Radiological anatomy of the coronariesOnly 14 pages are availabe for public view
 |  | from | 201 |  |  |
| | | from | 201 | | |
Abstract
• Noninvasive coronary CTA and MRA represent substantial advances that may ultimately be valuable for diagnosis of significant coronary artery disease.
• Coronary CTA is very reliable, especially in:
o Direct visualization of coronary anatomy. Importantly, due to its high negative predictive value, the technique may be particularly suited to rule out obstructive CAD in patients who have intermediate pretest likelihood of disease.
o CTCA and the triple rule out may be part of the chest pain evaluation in the emergency department setting.
o To some extent, MSCT can provide information on plaque composition. Although exact identification of plaque composition and morphology remains difficult, the opportunity to directly visualize atherosclerotic plaques may offer an important advantage over invasive coronary angiography.
o It may be reasonable to consider use of CAC measurement by coronary CT scanning in asymptomatic patients with intermediate CHD risk (between 10% and 20% 10-year risk of estimated coronary events) This conclusion is based on the possibility that such patients might be reclassified to a higher risk status based on high CAC score, and subsequent patient management may be modified
• Despite substantial technical improvements in MR technology, 3D MR coronary angiography is not sufficiently well developed for the detection of significant coronary artery stenosis in the clinical setting. Image quality is not consistently reliable, the overall image quality is inadequate in some patients, and the distal coronary artery segments may not be visualized.
• However, MR coronary angiography is effective for the detection of significant stenosis in the proximal segments of coronary arteries. Also, MR imaging was helpful in the interpretation of coronary stenosis in severely calcified segments, in which CT angiography can be misleading or insufficient.
• CMR is considered as the gold standard for assessment of myocardial viability, which is probably the single most important use of CMR in CAD at the present time.
• With an advent of new non-invasive imaging techniques, diagnostic and therapeutic strategies for patients with CAD have become more complicated than ever. Basically, noninvasiveness is the first priority for patients with low and intermediate risk factors. In this line, coronary MRA would be the first choice of diagnostic modality in asymptomatic patients and in patients with low pretest likelihood of CAD. Coronary MSCT angiography use might be limited to patients with intermediate pretest likelihood of CAD because MSCT requires and injection of contrast medium, there is still some radiation exposure.
• In conclusion, initially, MR-CA was somewhat superior to CT-CA. But significant improvements in CT hardware and software, and evolution from 64-slice to 320-slice scanner, have been more rapid than improvements in MR techniques and, today, the contest regarding the diagnostic accuracy between the 2 noninvasive imaging modalities has been settled in favor of CT-CA in diagtnosis of CAD and in favor of CMR in evaluation of myocdrdial perfusion and viability.