Noninvasive coronary artery imaging: magnetic resonance angiography and multidetector computed tomography angiography: a scientific statement from the american heart association committee on cardiovascular imaging and intervention of the council on cardiovascular radiology and intervention, and the councils on clinical cardiology and cardiovascular disease in the young.

Since the early 1960s, selective x-ray coronary angiography has provided the only means of visualizing the coronary arterial system in vivo. However, it has several disadvantages. First, the incidence, albeit relatively low, of so-called major adverse events (death, myocardial infarction, or stroke) during or within 24 hours of selective coronary angiography is reported to be 0.2% to 0.3%, and the incidence of so-called minor complications (most of which are related to problems with the peripheral vessels through which catheters are inserted) is roughly 1% to 2%.1–3 Second, x-ray coronary angiography is accompanied by a modest amount of discomfort, because the placement of catheters is invasive. Third, it is expensive: the required equipment is costly, and the performance of the procedure necessitates considerable time and skill of highly trained physicians and support personnel. Last, the information obtained via catheter-based coronary angiography pertains to the coronary arterial lumen alone. As a result, alternative methods of visualizing the coronary arterial system that would allow one to avoid these disadvantages are desirable. Over the past 15 years, substantial advances have been made in noninvasive cardiac imaging in general and in visualization of the coronary arteries in particular. Magnetic resonance angiography (MRA) of the coronary arteries was advanced in the early 1990s with the development of high-speed gradient techniques and dedicated cardiac coils. The primary advantage of this technique is the patient’s lack of exposure to ionizing radiation or iodinated contrast media. Coronary MRA may also be combined with other magnetic resonance (MR) imaging techniques for assessment of cardiac function, structure, blood flow, and viability.4 Electron-beam computed tomography (CT) with iodinated contrast injection was originally used to perform coronary angiograms, but this has been supplanted by multidetector CT (MDCT) scanners that have 16 to 256 rows of detectors. MDCT can provide visually compelling images of the coronary arterial tree, although at present, the necessary radiation dose is higher than that associated with x-ray coronary angiography. In this statement, we discuss and summarize these two noninvasive modalities, MRA and computed tomographic angiography (CTA), which may be used for coronary artery evaluation. Because the advantages and limitations of CT to assess the presence and extent of coronary arterial calcification are discussed in a separate document sponsored by the American Heart Association, the assessment of coronary arterial calcification is not presented in this statement. For both MRA and CTA, we provide a discussion of technical issues, applications, advantages, and