Dr. Yining Wang and colleagues at Peking Union Medical College Hospital evaluated 122 postmenopausal women with ECG-gated 16-slice CT for calcium score and stenosis (greater than 70%). The women, all faculty members at the hospital, were divided into two groups: 54 who had taken HRT for more than five years and 75 who had never taken HRT. Wang reported the study at the 2005 European Congress of Radiology.

The researchers found a significant difference in calcium scores: 29.6 in the HRT group versus 125.8 for the control group. They also found a significant difference in the rate of stenosis: 9.6% in the HRT group versus 24.3% in the control group.

The beneficial effects of HRT include vasodilation and modulation of some vessel components such as lipoproteins and coagulation. But HRT also involves some risks, such as stimulating an inflammatory response.

"The cardiovascular risk from HRT remains controversial. It is urgent that we find the right dosage that could retain HRT's beneficial effect and reduce the cardiovascular risk," Wang said.

In another study led by Wang, researchers evaluated the image quality of coronary CT angiography. They used a 16-slice scanner to examine 188 patients with suspected coronary artery disease. Patients with heart rates above 65 bpm received beta blockers. All studies were reconstructed into maximum intensity projections and volume-rendered images.

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.

Wang recommended nine positions of volume-rendered images to view different parts of the heart, especially the caudal view, which is difficult to achieve in conventional angiography.