| Background and purposeCoronary artery disease (CAD) is the one of the most cause of morbidity and mortality death in global and accounts for about 30 percent of all global deaths, The largest percentage will continue to increase in the future, People both in low-and higher-income countries who suffer from CADs,64-slice computed tomography coronary angiography is a routine technique used safely for the diagnosis of patients suspected of having Coronary artery disease (CAD),Invasive coronary angiography (ICA) is the routine and most reliable imaging technique for detecting CAD, Coronary computed tomographic angiography (CCTA) has increasingly gained importance as a fast, accurate and noninvasive method of diagnosing coronary artery diseaseo The aim of the study is to investigate the relationship between Peak CT value of the ascending aorta size and delay time of the optimization of relations contrast media in 64-slice CT coronary angiography, Heart rate, body mass index, age, gender, and ascending aorta peak CT value of the correlation, according to the coronary artery scan time delay influencing factors, we must select the exact delay scan time, making use of the ECG current modulation scanning technique to ensure high-quality images at the same time, Which can be reduced radiation doses effectively. Materials and MethodsA total of 150 patients underwent 64-slice spiral CT coronary angiography, (70 male,80 female, mean age of 54 years, from 31 to 88 years). We use Timing bolus scanning technology before scan coronary artery.The data which selected the 75% phase were transferred to computer workstation ADW4.3 and was calculated and analyzed using post-processing software, the coronary arteries (the level of the left coronary artery) was measured by placing ROIs of 50mm2 and measured three times for each site to the mean value. Records of subjects before scanning personal information Which something included Heart rate(bpm),Weight (kg),BMI (kg/m2),gender(G),age (A),height (H),Peak time of aorta maximum enhancement Delayed scan time.It was Selected 40 examples in 150 patients to divide into ranodm groups 1,2, n=20> The group 1 of scanning forecast delay time is the ascending aorta reaches the peak time based on timing bolus to plus 4 seconds. The group 2 of scanning forecast delay time is the peak time in the ascending aorta to plus 5 seconds.Two groups of images CT value size is measured by placing ROIs of 50mm2,andmeasured three times for each site to the mean value on veins, the right ventricle, the right atrium, the pulmonary artery, the pulmonary vein, the left atrium, the left ventricle, the coronary artery, the coronary vein.A total of 60 patients(28 males,32 females) who were randomly selected inl50 patients which heart rate regular and the heart rate were less than 70 times/min, the first 30 patients were assigned to protocol A, and the next 30 patients to protocol B, A group using the traditional way of scanning a fixed mA, B group according to body mass index table to select the maximum number of rows and use ECG mA output current modulation scan technology, we measured two sets of image noise index value and the records of CTDIvol,ED values, and evaluated the image quality of the two groups.In this study, each group of data on 150 patients was normal distribution, and homogeneity of variance. The aim of the study is to investigate the relationship between Peak CT value of the ascending aorta size and delay time of the optimization of relations contrast media in gender, age, body mass index, heart rate of coronary artery (left coronary artery level) in stepwise multiple regression analysis by statistical software SPSS15.0.It was measured to two group of 1,2 group patient's on superior venae cavaes, the right ventricle, the pulmonary artery, the pulmonary vein, the left ventricle, the coronary artery, coronary vein's CT value carries on the normality examination, The data of two groups of patients were normal distribution. Possible differences in data of two group of patient's were tested by Independent-samples t-test by SPSS 15.0 statistical software. Values of P<0.05 were considered significant.It was measured to two group of A, B group patient's with different scan methods on dose index (CT dose index, CTDIvoi), the effective dose (effective dose ED), image noise, phase images of 14 coronary artery score. The data of two groups of patients were normal distribution. Possible differences in data of two group of patient's were tested by Independent-samples t-test by SPSS 15.0 statistical software. Values of P<0.05 were considered significant.Result1. Delayed scan time of the relevant factorsThere was not statistical significance between the body weight index and the time of reaches the peak.as to the time of reaches the peak,we can say fast to female than to male, The age has positive correlation with the crown arteries reach the peak time. The heart rate has negative correlation with the crown arteries reach the peak time; There has not statistical significance between The heart rate and the crown arteries reach the peak CT value, The body weight index has negative correlation with the crown arteries reach the peak time, The age has positive correlation with the crown arteries reach the peak CT value.we also can say as to the peak CT value to The female were higher than to the male.2. There was not statistical significance between group 1 and group 2 in terms of age> gender,weight,height,heart rate. There was not significantly different (P=0.309) between the two groups were apparent in terms of coronary vein comparison subjects. There were significantly different (P<0.05) between the two groups of CT value comparison were apparent in terms of the superior vena cava,the right ventricle,the pulmonary artery,the pulmonary vein,the left ventricle,the coronary.3. A group of 30 patients, CTDIVOL (CT dose index weighted,mean of 77.02±5.25 (mGy), the effective dose (effective dose ED, mean of 22.19±2.72 (m Sv); B group, 30 cases subjects, CTDIvol (CT dose index weighted,mean of 52.11±14.34 (mGy), the effective dose (effective dose ED, mean of 15.24±4.19 (m Sv); There were significantly different(P<0.05) between the A and B groups of comparison were apparent in terms of the ED values obtained and CTDIvol size. There was not significantly different (P>0.05) between the A and B groups of comparison were apparent in terms of noise index and Image quality score.Conclusion:1. There was not statistical significance between the body weight index and the time of leaches the peak.as to the time of reaches the peak,we can say fast to female than to male, The age has positive correlation with the crown arteries reach the peak time.The heart rate has negative correlation with the crown arteries reach the peak time; There was not statistical significance between the heart rate and the crown arteries reach the peak CT value, The body weight index has negative correlation with the crown arteries reach the peak time, The age has positive correlation with the crown arteries reach the peak CT value.we also can say as to the peak CT value to The femalewere higher than to the male.2. When timing bolus scan predict delayed scanning time and injection rate of 5ml /s, It is easier to reach the peak of coronary artery plus 5 seconds than plus 4 seconds.3. It is using of the ECG current modulation scanning technique to ensure high-quality images at the same time, can be reduced radiation doses effectively. |
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