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

Jorg Hausleiter, MD, Bernhard Bischoff, MD, Franziska Hein, MD, Tanja Meyer, MD, Martin Hadamitzky, MD, Carsten Thierfelder, PhD, Thomas Allmendinger, PhD, Thomas G. Flohr, PhD, Albert Schomig, MD, Stefan Martinoff, MD

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 X 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.