Image quality and radiation dose of a prospectively electrocardiography-triggered high-pitch data acquisition strategy for coronary CT angiography: The multicenter, randomized PROTECTION IV study.
BACKGROUND
Concerns have been raised about radiation dose of coronary CT angiography. Although high-pitch acquisition technique yields high potential for radiation dose savings, it is more vulnerable to artifacts, which impair diagnostic image quality.


OBJECTIVE
The purpose of this study was to compare 2 scan strategies for coronary CT angiography: a high-pitch helical scan first or a conventional scan first strategy.


METHODS
In this prospective, multicenter trial, we randomized 303 consecutive patients with a low and stable heart rate to either of the aforementioned mentioned strategies. Intravenous β-blockers were administered to achieve target heart rates. All scans were performed on a second-generation dual-source CT scanner. In case of nondiagnostic image quality, coronary CT angiography was allowed to be repeated. The primary end point was to demonstrate noninferior image quality in the high-pitch group. Image quality was assessed on a 4-point scale (1: nondiagnostic, 4: excellent). Secondary end point was total radiation dose.


RESULTS
In the high-pitch helical first group, repeat scanning was necessary in 21 patients compared with 14 patients in the conventional first scan group (P = .25). Image quality in the high-pitch group was noninferior compared to the conventional scan group (3.81 ± 0.35 vs. 3.83 ± 0.37; P for noninferiority <.0001). The total effective radiation dose estimate was 58% lower in the high-pitch group (2.0 ± 2.4 vs. 4.7 ± 4.8 mSv; P < .0001).


CONCLUSIONS
In patients with a low and stable heart rate diagnostic image quality can be maintained with a high-pitch helical scan first strategy while 58% of radiation dose can be saved.
Medizinische Klinik und Poliklinik I der Ludwig-Maximilians-Universität München, Marchioninistr 15, Munich 81377, Germany.
Simon
S
Deseive
Barts and The London NIHR Cardiovascular Biomedical Research Unit, William Harvey Research Institute, Barts and The London School of Medicine, The London Chest Hospital, London, Great Britain.
Francesca
F
Pugliese
Instituto Nacional de Cardiología 'Ignacio Chávez', Universidad Nacional Autónoma de México, Ciudad de México, México.
Aloha
A
Meave
Instituto Nacional de Cardiología 'Ignacio Chávez', Universidad Nacional Autónoma de México, Ciudad de México, México.
Erick
E
Alexanderson
Institut für Radiologie und Nuklearmedizin, Deutsches Herzzentrum München, Klinik an der Technischen Universität München, Munich, Germany.
Stefan
S
Martinoff
Institut für Radiologie und Nuklearmedizin, Deutsches Herzzentrum München, Klinik an der Technischen Universität München, Munich, Germany.
Martin
M
Hadamitzky
Medizinische Klinik und Poliklinik I der Ludwig-Maximilians-Universität München, Marchioninistr 15, Munich 81377, Germany.
Steffen
S
Massberg
Medizinische Klinik und Poliklinik I der Ludwig-Maximilians-Universität München, Marchioninistr 15, Munich 81377, Germany. Electronic address: joerg.hausleiter@med.uni-muenchen.de.
Jörg
J
Hausleiter
D000368:Aged; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
CT; Coronary CT angiography; Flash mode; High-pitch helical; Radiation dose