| ObjectiveTo explore and evaluate the effect of heart rate (HR) and heart rate variability (HRV) on image quality of dual-source computed tomography (DSCT) coronary angiography.Methods107 consecutive patients underwent DSCT coronary angiography in our hospital from February 2010 to May 2010(69 males and 38 females with average age of (52.46±10.10)years, mean heart rate of (84.53±17.36)bpm and mean heart rate variability of (9.21±3.67)bpm. The patients were divided into 3 groups according to heart rate (HR) (HR≤75bpm,75bpm100bpm) and 2 groups according to heart rate variability(HRV) (HRV≤10bpm,HRV>10 bpm). The x-ray tube voltage and electric current were 120Kv and 420mAs. The images were reconstructed with the best systolic or diastolic phases. Coronary arteries were divided into 15 segments and the image quality of any coronary segments was evaluated. All data were analyzed with SPSS 11.5. Use Pearson product moment analysis to analyze the correlation of HR and HRV on image quality of noninvasive coronary angiography with DSCT. Further analysis would be performed if the statistical significance was found.ResultsAmong 1059 segments, 1049 segments could be evaluated. There were 362 segments with one-grade image quality, 560 segments with two-grade image quality, 127 segments with three-grade image quality and 10 segments with four-grade image quality. The total score of coronary artery was (1.72±0.44).1. The image quality scores of each segments were analyzed with Pearson product moment analysis. A weak correlation was found between HR and image quality of the mid segment of RCA and total RCA(r=0.192, P<0.05 and r=0.210, P<0.05). No significant difference was found between HR and image quality of the others.2. No significant difference was found between different HR groups on image quality of the mid segment of RCA and total RCA(F=0.998, P>0.05 and F=0.408, P>0.05).ConclusionDSCT had two tube ball-detectors, which made it obtain the temporal resolution of 83ms, so that the images of DSCT coronary angiography is sufficient for diagnosis in a wide range of HR and HRV. Altough the image quality was affected by HR, combining different phases images could make right diagnosis. ObjectiveTo evaluate the diagnostic accuracy of DSCT cronary angiography(CTCA) in the diagnosis of coronary artery diseases comparing with X-ray coronary artery angiography(CAG).Methods54 patients underwent CTCA in our hospital from March 2010 to November 2010(37 males and 17 females with an average age of (60.43±10.96)years and mean heart rate of (74.76±12.32)bpm. All the patients underwent CAG within following two weeks. The tube voltage and electric current were 120Kv and 420mA, respectively. The pitch during scan changed automatically according to the heart rate. Coronary arteries were divided into 15 segments and the stenosis degree of each segment was evaluated. All data were analyzed with SPSS 11.5. The diagnoses of CTCA and CAG in coronary artery diseases was compared withχ2-Test.Results1. According to DSCT coronary angiography and CAG, there were 488 segments with no stenosis, 57 segments with low-grade stenosis, 35 segments with medium stenosis, 33 segments with serious stenosis and 4 segments with occlusion. The results of Kappa analysis displayed that there was high consistency between CTCA and CAG in the diagnosis of coronary artery diseases(kappa value=0.85).2. According to CTCA and CAG, there were 488 segments with no stenosis and 134 segments with stenosis. The results ofχ~2-Test showed that there was no significant difference between CTCA and CAG in the diagnosis of coronary artery diseases(χ~2=1.09, P>0.05). The sensitivity, specificity, postive predictive value, negative predictive value and the accuracy rate of the diagnosis of coronary artery diseases were 91.2%, 96.1%, 87.0%, 97.4% and 94.2%, respectively.3. According to CTCA and CAG, there were 72 segments with >50% stenosis and 566 segments with≤50% stenosis. The results ofχ~2-Test showed that there was no significant difference between CTCA and CAG in the diagnosis of coronary artery diseases with >50% stenosis (χ~2=2.4, P>0.05). The sensitivity, specificity, postive predictive value, negative predictive value and the accuracy of the diagnosis of coronary artery diseases were 86.7%, 99.3%, 94.7%, 98.1% and 97.7%, respectively.ConclusionThe sensitivity, specificity, postive predictive value and negative predictive value were high in diagnosis of coronary artery diseases, especially negative predictive value. So, DSCT could be used as a screening method of coronary artery diseases. ObjectiveTo explore the feasibility of DSCT coronary angiography(CTCA) with low-dose x-ray and retrospective electrocardiogram triggering.Methods52 patients underwent CTCA in our hospital from October 2010 to December 2010, aged from 35 to 80 years, with HR<80bpm and BMI<3kg/cm2. The patients were divided into high-dose group(group A) and low-dose group(group B). 27 patients in group A were examed with x-ray tube voltage 120Kv and tube electric current 420 mAs. 25 patients in group B were examed with x-ray tube voltage 100Kv and tube electric current 360 mAs. The dose parameters of patients in two groups were recorded and the noise of the images was measured with the ROI in the Aorta. Coronary arteries were divided into 15 segments and the image quality was evaluated. All data were analyzed with SPSS 11.5. All continuous data were expressed as mean±standard deviation ( x±s). Dose parameters, noise and image quality of two groups were compared with two independent samples t-Test. Results1. The pitch of group A was (0.30±0.04). The pitch of group B was (0.32±0.04). There was no significant difference between the two groups (t=-1.60, P>0.05).2. 328 segments were evaluated in group A. The rate of good image was 93.3%. 300 segments were evaluated in group B. The rate of good image was 90.67%. The scores of images in two groups were (1.72±0.38) and (1.79±0.38). There was no significant difference between the two groups (t=-0.72, P>0.05).3. The ROI square of the two groups were (1.51±0.02)cm~2 and (1.51±0.03) cm~2. There was no significant difference between the two groups (t=-0.03, P>0.05). The image niose value of the two groups were (18.66±3.55) Hu and ( 27.02±4.74) Hu. There was a significant difference between the two groups (t=-7.23, P<0.05). The image noise value of group B was higher than group A.4. The CTDIvol, DLP and ED of group A were (71.57±9.39)mGy, (1088.78±185.85)mGy·cm, (15.24±2.60)mSv. The CTDIvol, DLP and ED of group B were (33.46±3.68)mGy, (496.52±61.04)mGy·cm, (6.94±0.85)mSv. There were significant differences beween dose parameters (CTDIvol, DLP and ED) of two groups (t=19.53, t=15.70, t=15.70, P<0.05). The radiation dose of group A was higher than that of group B .ConclusionDSCT coronary angiography with retrospective electrocardiogram triggering was hardly affacted by heart rate. Alhough patients were examed with low dose, the failure rate of examination is very low. Good images could be obtained with tube voltage 100Kv and tube electric current 360mAs in patients with BMI<30kg/cm~2. |
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