Prospectively Electrocardiogram-Gated High-Pitch Spiral Acquisition Mode Dual-Source CT Coronary Angiography in Patients with High Heart Rates: Comparison with Retrospective Electrocardiogram-Gated Spiral Acquisition Mode

OBJECTIVE: To assess the image quality and effective radiation dose of prospectively electrocardiogram (ECG)-gated high-pitch spiral acquisition mode (flash mode) of dual-source CT (DSCT) coronary angiography (CTCA) in patients with high heart rates (HRs) as compared with retrospectively ECG-gated spiral acquisition mode. MATERIALS AND METHODS: Two hundred and sixty-eight consecutive patients (132 female, mean age: 55 +/- 11 years) with mean HR > 65 beats per minute (bpm) were prospectively included in this study. The patients were divided into two groups. Collection was performed in group A CTCA using flash mode setting at 20-30% of the R-R interval, and retrospectively ECG-gated spiral acquisition mode in group B. The image noise, contrast-to-noise ratio (CNR), image quality scores, effective radiation dose and influencing factors on image quality between the two groups were assessed. RESULTS: There were no significant differences in image quality scores and proportions of non-diagnostic coronary artery segments between two groups (image quality scores: 1.064 +/- 0.306 [group A] vs. 1.084 +/- 0.327 [group B], p = 0.063; proportion of non-diagnostic coronary artery segments: segment-based analysis 1.52% (group A) vs. 1.74% (group B), p = 0.345; patient-based analysis 7.5% (group A) vs. 6.7% (group B), p = 0.812). The estimated radiation dose was 1.0 +/- 0.16 mSv in group A and 7.1 +/- 1.05 mSv in group B (p = 0.001). CONCLUSION: In conclusion, in patients with HRs > 65 bpm without cardiac arrhythmia, the prospectively high-pitch spiral-acquisition mode with image-acquired timing set at 20-30% of the R-R interval provides a similar image quality and low rate of non-diagnostic coronary segments to the retrospectively ECG-gated low-pitch spiral acquisition mode, with significant reduction of radiation exposure.

Dual-Source Computed Tomographic Coronary Angiography:Image Quality and Stenosis Diagnosis of Patients with High Heart Rates / 医疗卫生装备

Objective To prospectively evaluate the effects of heart rate and heart-rate variability on dual-source computed tomographic coronary image quality in patients with high heart rates,and to determine retrospectively the accuracy of dualsource computed tomographic diagnosis of coronary artery stenosis in the same patients.Methods The image quality and diagnostic accuracy were compared between the normal group of 40 patients whose heart rates exceeded 70 beats/min and the control group of 40 patients whose heart rates were 70 beats/min or slower.Results No statistically significant differences between the groups were found in diagnostic-image quality scores of total segments or of any coronary artery,nor were any significant differences found between the groups in the accurate diagnosis of angiographically significant stenosis.Calcification was the chief factor that affected diagnostic accuracy.In high -heart -rate patients,heart -rate variability was significantly related to the diagnostic image quality of all segments(P=0.001) and of the left circumflex coronary artery(P=0.016).Heart-rate variability more than 5 beats/min most strongly contributed to an inability to evaluate segments in both groups.When heart rates rose,the optimal reconstruction window shifted from diastole to systole.Conclusion The image quality of dual -source computed tomographic coronary angiography at high heart rates enables sufficient diagnosis of stenosis,although variability of heart rates significantly deteriorates image quality.