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Non-invasive imaging of coronary artery with 16-slice spiral computed tomography.

OBJECTIVE
To evaluate the value of 16-slice spiral CT in the demonstration of coronary artery and in the diagnose of coronary artery stenosis.


METHODS
Plain and enhanced CT scans were performed with a 16-slice CT scanner (Sensation 16, Siemens, Germany) in 230 patients with suspected coronary heart disease (CHD). Parameters of the plain scan were: 120 kV, 133 mA, slice collimation 16 mm x 1.5 mm, rotation time 0.42 seconds, increment 1.5 mm, and slice width 3 mm. Parameters of the enhanced scan were: 120 kV, 500 mA, slice collimation 16 mm x 0.75 mm, rotation time 0.42 seconds, increment 0.5 mm, and slice width 1 mm. Enhanced CT scan was performed with a rapid intravenous injection of 100 mL iothalamate meglumine (Ultravist) (370 mgI/mL) or Omnipaque (350 mgI/mL) and 30 mL 0.9% NaCl chaser bolus at a flow rate of 3.5 mL/s. Calcium scoring with plain scan images and two and three dimensional reconstruction with enhanced scan images were made in all cases, among which 30 cases underwent conventional coronary angiography. Demonstration of coronary arteries and their stenosis were evaluated and the factors that might influence the image quality were analyzed.


RESULTS
Coronary calcium scores were calculated and coronary artery was demonstrated in our study. In the evaluation of image quality with volume rendering technique (VRT) images, 78.3% of the images were of the first class, 12.2% the second class, and 9.6% the third class. Multi-planar reconstruction (MPR) and maximal intensity projection (MIP) were better than VRT in the demonstration of small branches. The image quality was related to the heart rate, with or without arrhythmia, and breath-hold ability of patients. Comparative study of the stenosis of coronary arteries in 30 cases showed that the sensitivity and specificity of 16-slice coronary CT angiography (CTA) to diagnose significant stenosis were 95.8% and 94.8% respectively.


CONCLUSION
As a non-invasive and quick method, 16-slice coronary CTA is sensitive and specific to diagnose the stenosis of coronary arteries and can be used as a screening method in the diagnosis of CHD.