Initial evaluation of coronary images from 320-detector row computed tomography

Area of Science:

• Cardiovascular Imaging
• Radiology
• Medical Technology

Background:

• Coronary artery imaging using computed tomography (CT) is crucial for diagnosing cardiovascular diseases.
• Advancements in CT technology, such as 320-detector row systems, aim to improve image quality and reduce patient dose.
• Evaluating the performance of new CT technologies is essential for clinical adoption.

Purpose of the Study:

• To assess the image quality and contrast opacification of coronary arteries using 320-detector row CT.
• To estimate patient radiation dose for different scanning protocols, including prospective and retrospective ECG-gating.
• To perform an initial correlation between 320-detector row CT findings and conventional coronary catheterization.

Main Methods:

• Retrospective analysis of coronary CT angiography in 40 patients.
• Subjective and objective assessment of image quality and contrast opacification.
• Measurement of contrast opacification gradient in coronary arteries.
• Comparison of effective radiation dose based on ECG-gating, body mass index, and acquisition type (single vs. two heartbeats).
• Correlation of CT findings with coronary catheterization data where available.

Main Results:

• Over 89% of coronary arterial segments demonstrated excellent image quality, with cardiac motion being the primary cause of degradation.
• Contrast opacification was consistently excellent, with mean Hounsfield units (HU) above 350 and a contrast opacification gradient of 30-50 HU.
• Patient radiation dose was higher with retrospective ECG-gating, in larger patients, and for two-heartbeat acquisitions. A common prospective ECG-gating protocol resulted in a mean dose of 6.8 ± 1.4 mSv.
• CT findings were confirmed in all patients who underwent coronary catheterization.

Conclusions:

• Initial 320-detector row coronary CT imaging yields excellent image quality and contrast opacification.
• Current protocols utilize conservative settings for iodine load, ECG-gating, and coverage.
• Future research will focus on optimizing protocols to reduce contrast and radiation dose while maintaining diagnostic image quality.