Minimizing the acquisition phase in coronary CT angiography using the second generation 320-row CT

Area of Science:

• Radiology
• Cardiovascular Imaging

Background:

• Coronary CT angiography (CCTA) is crucial for diagnosing coronary artery disease.
• Optimizing radiation dose while preserving diagnostic image quality remains a key challenge in CCTA.

Purpose of the Study:

• To compare radiation dose and image quality between a minimal phase window (77%) and a wide phase window (65-85%) in CCTA.
• To evaluate the efficacy of a minimal phase window protocol on a second-generation 320-row CT scanner.

Main Methods:

• Retrospective analysis of 80 patients undergoing CCTA with heart rate ≤75 bpm.
• Patients were divided into two groups: wide phase window (n=40) and minimal phase window (n=40).
• Radiation dose was calculated from dose length product; image quality was assessed subjectively and objectively (noise, CNR).

Main Results:

• Minimal phase window scanning reduced radiation dose by 30% (1.7 vs 2.4 mSv, p=0.0009).
• No significant difference in subjective image quality was observed between the two groups (3.75 vs 3.76, p=0.77).
• Image noise, CT number, and contrast-to-noise ratio remained comparable.

Conclusions:

• A minimal phase window centered at 77% effectively reduces radiation dose in CCTA.
• This technique allows for dose reduction without compromising diagnostic image quality.
• The findings support the use of minimal phase windows for optimized CCTA protocols on 320-row CT systems.