Summary

Background: Coronary CT angiography is an accurate imaging modality; however, its main drawback is the radiation dose. A new technology, the "step and shoot," which reduces the radiation up to one-eighth, is now available.

Objectives: To assess our initial experience using the "step-and-shoot" technology for various vascular pathologies.

Methods: During a 10 month period 125 consecutive asymptomatic patients (111 men and 14 women aged 25–82, average age 54.9 years) with various clinical indications that were appropriate for step-and-shoot CCTA[1] (regular heart rate < 65 beats/minute and body weight < 115 kg) were scanned with a 64-slice multidetector computed tomography Brilliance scanner (Philips, USA). The preparation protocol for the scan was the same as for the regular coronary CTA. All examinations were interpreted by at least one experienced radiologist and one experienced interventional cardiologist. The quality of the examinations was graded from 1 (excellent imaging quality of all coronary segments) to 4 (poor quality, not diagnostic). There were 99 patients without a history of coronary intervention, 13 after coronary stent deployment (19 stents), and 3 after coronary artery bypass graft.

Results: Coronary interpretation was obtained in 122 examinations (97.6%). The imaging quality obtained was as follows: 103 patients scored 1 (82.4%), 15 scored 2 (12%), 4 scored 3 (3.2%) and 3 scored 4 (2.4%). The grades were unrelated to cardiac history or type of previous examinations. Poor image quality occurred because of sudden heart rate acceleration during the scan (one patient), movement and respiration (one patient), and arrhythmia and bad scan timing (in one). Two patients were referred to percutaneous coronary intervention based on the CCTA findings, which correlated perfectly.

Conclusions: Step-and-shoot CCTA is a reliable technique and CCTA algorithm comparable to the regular CCTA. This technique requires the lowest radiation dose, as compared to other coronary imaging modalities, that can be used for all CCTA indications based on the inclusion criteria of low (> 65 bpm) and stable heart rate.