CTA image quality depends on heart rate, aortic root density

Heart rate and CT density at the aortic root significantly affect image quality in coronary CT angiography, according to a study presented at the European Congress of Radiology.

Dr. Yining Wang and colleagues from Peking Union Medical College Hospital evaluated the image quality of coronary CTA in 188 patients with suspected coronary artery disease using a 16-slice scanner. Patients with heart rates above 65 bpm received beta blockers. All studies were reconstructed into maximum intensity projections and volume rendered images.

The left main, left anterior descending, left circumflex, and right coronary arteries were evaluated for image quality. Results were divided into three groups:

• class I: no motion artifacts

• class II: mild motion artifacts

• class III: severe motion artifacts

Class I contained 85% of 610 branches, while 11% were in class II, and 4% in class III. The left main artery had more branches in class I, while the right coronary artery had the fewest.

CT density in the origin of the aorta was highest in class I and lowest in class III. Lower heart rates were associated with images in class I, while higher rates were associated with class III. Logistic regression analysis indicated that heart rate and CT density in the root of the aorta have the most significant impact on image quality, Wang said.

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