Effects of Heart Rates and Variability of Heart Rates on Image Quality of Dual-Source CT Coronary Angiography

The dual-source CT (DSCT) equipped with two X-ray tubes at 90 degree offset in the gantry can provide temporal resolution 83ms using mono-segmental reconstruction technique. The recent studies about the effect of heart rate on IQ of DSCT coronary angiography which concluded in adequate diagnostic IQ of dual-source CTCA without immediate pre-scanning heart rate control included chronic users of β-blocker focused on the influences of average heart rate, heart rate variability and coronary arterial calcifications on IQ. The effect of blooming artifact of calcification on IQ by far cannot be eliminated. Here, we investigate the effects of maximum heart rate, average heart rate, minimum heart rate and heart rate variability on the motion-related IQ of DSCT coronary angiography in patients without both pre-scanning heart rate control and chronic use of β-blocker agent, compared with that in chronic users of β-blocker agents.

Inclusion criteria

• From Oct 2006 to Jan 2007, CT coronary angiographies of 180 consecutive adult patients, were performed in our hospital using a DSCT scanner. After exclusion of the patients according to the exclusion criteria, totally DSCT coronary angiographies of 133 adult patients (N=133) were enrolled in this study. Among those 133 patients, including 97 males and 36 females with a mean age of 53.9 (ranging from 21 to 78 year old), 50 patients were chronic β-blocker users (group 1) while the other 83 patients (group 2) were not chronic user of any medication controlling heart rate

Exclusion criteria

• The patients below 18 year old, patients with status post heterotopic heart transplantation (having two hearts in a chest), patients with status post coronary by-pass surgery and patients with post indwelling of coronary arterial stents