Low dose 320-row CT for left atrium and pulmonary veins imaging--the feasibility study

Area of Science:

• Radiology
• Cardiovascular Imaging
• Medical Physics

Background:

• Atrial fibrillation management often requires detailed imaging of the left atrium and pulmonary veins.
• Conventional CT angiography (CTA) protocols may involve significant radiation exposure.
• Optimizing imaging techniques to reduce dose while maintaining diagnostic quality is crucial.

Purpose of the Study:

• To assess the feasibility of a low-dose target-CTA volume scan protocol for imaging the left atrium and pulmonary veins using a 320-row CT scanner.
• To evaluate the impact of different tube voltage settings (100 kV vs. 120 kV) on image quality and radiation dose.

Main Methods:

• A prospective study involving 42 patients with atrial fibrillation undergoing catheter ablation.
• Implementation of a target-CTA volume scan protocol with prospective ECG-gating, focusing exposure on 40% of the R-R interval.
• Patients were divided into 100 kV and 120 kV groups based on BMI, with image quality, CT-attenuation, image noise, and contrast-to-noise ratio (CNR) assessed.
• Effective dose (ED) was calculated using a standard conversion coefficient.

Main Results:

• Good or moderate image quality was achieved in all 42 patients (62% good, 38% moderate).
• No significant differences in CT-attenuation or CNR were observed between the 100 kV and 120 kV groups.
• Mean effective dose was significantly lower in the 100 kV group (1.90 ± 0.19 mSv) compared to the 120 kV group (3.83 ± 0.31 mSv).

Conclusions:

• Low-dose target-CTA volume scanning is a feasible technique for left atrium and pulmonary vein imaging with 320-row CT.
• Utilizing a 100 kV setting is effective for imaging slim patients without compromising diagnostic image quality, thereby reducing radiation dose.