ABSTRACT
Objective To evaluate the application value of dual-source CT coronary angiography in low tube voltage setting and the influence of heart rate on image quality and radiation doses.Methods 323 patients suspected of coronary artery disease received retrospective ECG-gating coronary angiography with dual-source CT scanner,who were divided into low tube voltage group (100 kVp,n =201) and conventional voltage group (120 kVp,E group,n =122).No beta-blockers were taken before CT scan.All patients in low tube voltage group were divided into four groups according to the heart rate (HR):group A,HR≤59 beats per minute (bpm),n =50; group B,60≤HR ＜69 bpm,n =64; group C,70≤HR ＜91bpm,n =62;group D,HR ≥ 91 bpm,n =25.All images were transferred to a workstation for further processing.The best R-R interval reconstruction images of all groups were evaluated.The value of pitch,CT volume dosage index(CTDIvol),dose length product(DLP) and effective dose(E)were recorded.The pitch,the score of imaging quality of coronary artery segments and the radiation dose were compared with One-Way ANOVA.The influence of heart rate on image quality and radiation doses of coronary artery was analyzed.Results The value of pitch in groups A-D was 0.24 ± 0.03,0.29 ± 0.04,0.33 ± 0.05,0.38 ± 0.06,respectively,with statistical difference (F =62.57,P ＜ 0.05).The value of CTDIvol in groups A-E was (21.59±7.97),(20.24±6.03),(18.23±7.55),(18.14 ±5.75),(38.62±16.21)mGy,respectively,with statistical difference (F =85.16,P ＜ 0.05).The value of E in group A-E was (5.31 ±2.18),(4.85 ±1.70),(4.49 ± 1.86),(4.37 ±1.50),(8.75 ± 4.07) mSv,respectively,with statistical difference(F =44.83,P ＜ 0.05).The image score was (4.65 ±0.46),(4.55 ± 0.53),(4.55 ±0.53),(4.47 ±0.72),(4.66 ± 0.44) (F =1.89,P ＞ 0.05).Conclusions No beta-blockers was taken before CT scan,and a high quality image could be acquired by using dual-source CT coronary angiography in low tube voltage setting(100 kVp).When the auto ECG-gating is selected,medium and low HR have little influences on radiation dose,while the radiation dose could be decreased significantly at higher HR,but the possibility to obtain the high quality image decreased.
ABSTRACT
Objective To explore the clinical value of dual-source CT(DSCT) in the diagnosis of coronary artery disease by comparing the result of DSCT and coronary angiography(CAG).Methods From July 2009 to August 2010,36 patients with suspected coronary hear disease underwent both DSCT coronary angiography(DSCTCA) and selective GAG examination.The results of DSCT coronary angiography were compared with CAG which was the gold standard of diagnosing coronary disease.The sensitivity,specificity,positive and negative predictive value,and accuracy of DSCT were evaluated.Results 144 coronary arteries were well evaluated of 36 cases.The sensitivity,specificity,positive and negative predictive value,and accuracy of DSCT in the diagnosis of coronary hear disease were 100.00％,66.67％,93.75％,100.00％ and 97.20％ respectively by the number of patients;The McNemar test showed no significant difference between two methods( x2 =0.500,P ＞0.05 ) with a higher diagnosis concordance (Kapp =0.768,P ＜0.01).By detecting moderate to severe coronary artery stenosis,the sensitivity,specificity,positive and negative predictive value,accuracy were 95.24％,96.08％,90.91％,98.00％,95.83％,respectively.The McNemar test showed no significant difference between two methods(x2 =0.167,P ＞0.05) with a higher diagnosis concordance ( Kapp =0.899,P ＜ 0.01 ).Conclusion DSCT has a diagnostic accuracy of coronary heart disease close to that CAG,especially in evaluating patients with moderate to severe coronary artery stenosis,it has high compliance and consistency with CAG.DSCT is a noninvasive,safe and reliable radiographic method.