Feasibility of dual-source cardiac CT angiography with high-pitch scan protocols

Background: Cardiac CT angiography (CCTA) has become a frequently used diagnostic tool in clinical practice, but concern remains about the radiation exposure. Because of the second x-ray acquisition system, dual-source CT systems might allow for high-pitch CT data acquisition and thus for examination of the whole heart during a single heart beat, with the potential for radiation dose reduction. Objective: We assessed the feasibility of a high-pitch scan mode with a dual-source CT system. Methods: High-pitch modes were used in patients undergoing CCTA with a dual-source CT system. Diagnostic image quality for cardiac structures and coronary arteries was assessed. Radiation dose was estimated from the scanner-generated dose-length product (DLP). Results: CCTA was performed in 14 patients during a single heart beat applying a pitch value of 3.4. Mean heart rate during examination was 56.4 ± 8.1 beats/min. Diagnostic image quality for the assessment of larger cardiac structures was obtained in all patients, whereas diagnostic image quality could be achieved in 82% of all coronary segments. With a mean DLP of 145 ± 47 mGy × cm, the resulting estimated radiation dose was 2.0 ± 0.7 mSv. Conclusions: This proof-of-concept study shows the ability of dual-source CT scanners to scan the whole heart during one single heart beat at low radiation dose.