Radiation dose in cardiac CT angiography: protocols and image quality

Area of Science:

• Radiology
• Medical Imaging
• Cardiovascular Imaging

Background:

• Cardiac computed tomography angiography (CCTA) is crucial for diagnosing coronary artery disease.
• Optimizing radiation dose in CCTA is essential for patient safety.
• Different CCTA acquisition modes (prospective vs. retrospective) may impact radiation exposure and image quality.

Purpose of the Study:

• To evaluate and compare radiation dose exposure between prospective and retrospective CT angiography modes.
• To assess image noise and signal-to-noise ratios in both acquisition modes.
• To determine if prospective CCTA can maintain diagnostic image quality while reducing radiation dose.

Main Methods:

• Utilized 64- and 256-slice CT scanners for cardiac computed tomography angiography.
• Calculated effective radiation dose using dose-length product and European Working Group conversion factors.
• Measured image noise, contrast-to-noise ratio, and signal-to-noise ratio for all acquired images.

Main Results:

• Mean effective dose was 6.0±1.0 mSv for prospective and 8.4±1.2 mSv for retrospective CCTA.
• Prospective mode showed a 44.4% increase in mean image noise (38.5±9.5) compared to retrospective (21.4 ± 5.3).
• Prospective CCTA reduced radiation dose by approximately 29% while preserving diagnostic image quality.

Conclusions:

• Prospective CT angiography offers a significant reduction in radiation dose exposure for patients undergoing cardiac CT.
• The prospective mode effectively maintains diagnostic image quality, enabling accurate assessment of coronary artery obstructions.
• This study supports the use of prospective acquisition protocols for dose optimization in cardiac CT angiography.