Letter from the Editor

Article Outline

• Copyright

The recent advances in computed tomography (CT) technology have enabled us, radiologists, to rediscover a fascinating organ, the heart. Although it has been clearly visualized in every CT scan of the chest for the last three decades since the advent of CT, it has been almost disregarded for over twenty years. Yes, one could roughly assess the size of its chambers, comment on pericardial effusion or even on abundant coronary calcification, but the lungs and the mediastinum received much more attention until recently. The heart was definitely not at the forefront.

This has dramatically changed. CT has undergone rapid development since the inception of multi-detector-row computed tomography (MDCT) about a decade ago. This development was partly driven by the aspiration to reliably and accurately visualize the coronary arteries noninvasively. The opportunity to visualize the coronary anatomy is the major reason for the immense interest in cardiac MDCT. Cardiac CT has emerged as a major imaging modality for the noninvasive and comprehensive evaluation of coronary artery disease.

Obtaining a good coronary CT angiography (CTA) can be likened to a well-rehearsed orchestral concert—the musicians, their instruments, and the conductor need to be extremely well coordinated for optimal results. Similarly, perfect harmony between patient, contrast injection and scanning will result in an optimal coronary CTA. Such an optimal scan can be achieved with the appropriate knowledge and experience. The two first reviews provide the most essential basis of coronary CTA. The first one addresses the technical and clinical aspects of the study—a challenge due to the fact that the heart beats an average of 72 beats per minute in adults. The second one focuses on the normal anatomy of the heart and the coronary arteries. Familiarity with the normal anatomy is essential, just as in any other area of radiology, and has practical applications in recognizing anatomic variants and anomalies which may be clinically significant.

This leads us to the next article that focuses on the spectrum of congenital abnormalities of the coronary arteries, which although uncommon, constitute an important cause of chest pain and rarely may result in death. MDCT allows accurate and noninvasive depiction of coronary artery anomalies and is superior to conventional angiography in delineating the origin of the anomalous coronary artery and its path. Awareness of the CT appearances of various coronary artery anomalies and of their clinical significance is crucial in establishing the correct diagnosis and subsequent treatment.

One of the congenital anomalies of the coronary arteries, myocardial bridging, receives more extensive attention in the next review. Myocardial bridging is considered by some authors a congenital anomaly, while others refer to it as a normal variant. However, various clinical conditions including myocardial infarction and arrhythmias have been reported in association with this condition, thus pointing to its clinical importance. On conventional coronary angiography this condition may be indirectly diagnosed. In contrast, coronary CTA enables a superior and direct delineation of the course of the bridged segment and the surrounding myocardium.

One of the challenges of coronary CTA has been the visualization of the lumen of coronary artery bypass grafts. 64-slice scanners have overcome artifacts caused by cardiac motion as well as metal clips and poor opacification, thus leading to multiple reports on the accuracy of coronary CTA in evaluating graft stenosis and occlusion. The next review is a thorough literature review focusing on coronary artery bypass graft imaging with 64-slice scanners. It elucidates many facets of coronary CTA performed to evaluate coronary artery bypass grafts, including image acquisition and manipulation techniques, interpretative pitfalls and the diagnostic performance of 64-slice scanners following coronary artery bypass grafts.

The next review focuses on coronary stent assessment with 64-slice scanners. The number of percutaneous coronary interventions incorporating coronary stent implantation has rapidly risen over the past decade. Surveillance conventional coronary angiography is recommended within several months after the intervention due to the unpredictable occurrence of in-stent restenosis. In earlier generation scans visualization of the lumen within the stent was markedly hindered by artificial enlargement of the metallic stent struts caused by blooming artifact. However, 64-slice scanners are proving to have good diagnostic accuracy in evaluating in-stent restenosis.

The presence of coronary artery calcium is a specific marker of atherosclerotic disease. A non-contrast CT of the heart which usually precedes contrast injection can function as a means to quantify the coronary calcium score. This study can either be performed as a single non-contrast heart scan for qualification of personal cardiovascular risk, or as part of the contrast enhanced CTA examination. The last article explores the many aspects of coronary calcium scoring and provides a comprehensive literature review on this topic.

Currently, the use of coronary CTA does not constitute a broad replacement for diagnostic catheter-based coronary angiography, but available data indicate that, in certain clinical situations, it may be an alternative for selected patients. Undoubtedly, coronary CTA is a promising technique for noninvasive coronary evaluation.

I extend my appreciation and gratitude to the leading academic radiologists from all over the world, all experts in their field, who have contributed their time and expertise to provide excellent reviews.