Can the Coronary Artery Calcium Score Scan Reduce the Radiation Dose in Coronary Computed Tomography Angiography?

Rationale and Objectives: Radiation exposure from coronary computed tomography angiography (CCTA) remains a cause for concern. The objective of this study was to investigate whether using the coronary artery calcium score scan (CACS) would reduce the radiation dose for CCTA scanning and the overall radiation exposure (ORE). Materials and Methods: In total, 256 patients were examined with a third-generation dual-source CT (n = 200) or 256-row CT (n = 56), among whom 105 (Group A) and 28 patients (Group B), respectively, underwent CCTA with CACS for field of view planning. The remaining patients, with the scout view for field of view planning, constituted Group A1 and B1. The scanning parameter settings were standardized between groups. Results: Shorter scan lengths were observed in Group A (9.98 ? 0.79 cm) compared to Group A1 (13.64 ? 1.79 cm; p < 0.001), which also resulted in a lower dose-length product (DLP) in Group A (115.04 ? 64.13) relative to Group A1 (138.67 ? 68.87; p < 0.05). Similarly, shorter scan lengths were found in Group B (14.92 ? 1.17 cm) compared to Group B1 (15.79 ? 0.63 cm; p = 0.001); this resulted in a lower DLP (322.07 ? 45.39) compared to Group B1 (354.34 ? 65.27; p = 0.036). The CACS resulted in an increase in ORE in both groups. Conclusion: CACS may have a critical role in the reduction of radiation dose in CCTA scanning, but the potential effectiveness of CACS in reducing ORE is weak. Key Words: Computed tomography angiography; Coronary artery disease; Radiation exposure. ? 2020 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.Rationale and Objectives: Radiation exposure from coronary computed tomography angiography (CCTA) remains a cause for concern. The objective of this study was to investigate whether using the coronary artery calcium score scan (CACS) would reduce the radiation dose for CCTA scanning and the overall radiation exposure (ORE).Materials and Methods: In total, 256 patients were examined with a third-generation dual-source CT (n = 200) or 256-row CT (n = 56), among whom 105 (Group A) and 28 patients (Group B), respectively, underwent CCTA with CACS for field of view planning. The remaining patients, with the scout view for field of view planning, constituted Group A1 and B1. The scanning parameter settings were standardized between groups.Results: Shorter scan lengths were observed in Group A (9.98 +/- 0.79 cm) compared to Group A1 (13.64 +/- 1.79 cm; p < 0.001), which also resulted in a lower dose-length product (DLP) in Group A (115.04 +/- 64.13) relative to Group A1 (138.67 +/- 68.87; p < 0.05). Similarly, shorter scan lengths were found in Group B (14.92 +/- 1.17 cm) compared to Group B1 (15.79 +/- 0.63 cm; p = 0.001); this resulted in a lower DLP (322.07 +/- 45.39) compared to Group B1 (354.34 +/- 65.27; p = 0.036). The CACS resulted in an increase in ORE in both groups.Conclusion: CACS may have a critical role in the reduction of radiation dose in CCTA scanning, but the potential effectiveness of CACS in reducing ORE is weak.