Perspective:

Coronary CTA has clearly been demonstrated to be an accurate means of detection and exclusion of CAD, with negative predictive values of 100% being common in fairly large trials. The limitation of early algorithms for CTA was substantial radiation exposure as high as 12-30 mSv in earlier studies. This exceeds the exposure for invasive coronary arteriography, which averages 5-7 mSv. Multiple algorithms have been utilized to reduce the radiation exposure including ECG gating, modulating tube current during nonimaging periods, high-speed spiral dual-detector methodology, and using lower tube voltage. In this study, a high-pitch spiral acquisition was utilized, which reduces the number of overlapping images and hence the total exposure. These techniques allowed capture of the entire coronary tree during a single diastole with a significant reduction in estimated radiation exposure compared to many other protocols without a loss of accuracy. It should be emphasized that this was a fairly limited study with only 50 patients from the original cohort; one-third were excluded as being a nonideal candidate based on strict heart rate criteria or body weight >100 kg. As the major advantage of CTA is its exceptionally high negative predictive value (95-100% in virtually all studies), it may be an ideal tool for utilization in low-risk individuals, many of whom are likely to be either women or younger age, where there is legitimate clinical concern regarding radiation exposure. Reduction of the radiation exposure to the ≤1.0 mSv range, as demonstrated here, should go a long way toward alleviating many of these concerns.