Low Radiation Dose Triple Rule-out In Acute Chest Pain Using 64-slice Spiral CT

Objective To evaluate the feasibility of low radiation dose triple rule out in patients with acute chest pain using 64-slice spiral CT. Methods 97 consecutive patients underwent triple rule out[heart rate≤65bpm , range≤5bpm]. They were randomly divided into two groups A and B: 49 were in group A using prospective ECG-triggered axial scan protocol, 48 were in group B using retrospective ECG-gated scan protocol. (Body Mass Index)BMI≥24,120kV;BMI<24,100kV;Tube current is set according to BMI. Two doctors-in-charge above evaluated 13 segments of coronary tree in a double-blind manner according to the American heart association (AHA) coronary artery improved segmentation method. Inconsistent segments, two doctors came to an agreement after consultation. Coronary image quality score as quality control index, statistical software SPSS13.0 was used to analysis the data which include two groups of radiation dose, body mass index, scanning length, patients’heart rate fluctuating range in scanning. Data processed by two independent sample t-test, Wilcoxon Mann-Whitney test andχ2 test for fourfold . Results Both in group A and B has one failed,not included in the statistics. 95 cases successfully completed examination. 48 were in group A using prospective ECG-triggered axial scan protocol, 47 were in group B using retrospective ECG-gated scan protocol. The radiation dose of group A,B was 7.98±2.83 mSv,23.8±8.90mSv respectively. There was no significant difference between image quality of group A and B(u=1.40, p﹥0.05). Radiation dose of group A was decreased by 66.5% compared with that of group B(t=11.63,p<0.05). Conclusion Triple rule out in acute chest pain using prospective ECG-triggered axial scan protocol with 64-slice spiral CT can significantly reduce radiation exposure while maintaining image quality.