Clinic Application Of The Low-dose Imaging Technology Of Coronary Artery By 320 Row CT

PartⅠStudy on 320 row CT about the effect of scanning for coronary artery with low radioactive dosage1.Objectlve To evaluate the effect of 320 row CT with low radioactive dosage for coronary artery scanning.2.Methods (1) 170 patients suspected of coronary artery diseases were collected and randomly divided into 5 group from January 2010 to April 2010, used retrospective ECG-gating coronary artery imaging, Selected non-ionic contrast agent Ultravist (370 mg I / ml) 50ml, flow rate of 5.0ml / s, using 2 different start scanning methods by 320 row CT.①Automatic method: 120 patients were divided into 1～4 groups with different CT threshold (180HU,220HU,260HU,300HU) used surestart automatic control scan.②Manual method: 50 patients in groups 5 used surestart manual control scan. (2) 100 patients suspected of coronary artery diseases were collected and randomly divided into 2 group from April 2010 to May 2010. Groups 1(50 patients) used improve retrospective ECG-gating coronary artery imaging; Groups 2(50 patients) used retrospective ECG-gating coronary artery imaging. Both groups were used manual triggered scanning by 320 row CT. (3) 60 patients suspected of coronary artery diseases in the normal BMI range (between BMI<24 kg/m2 and BMI≥19 kg/m2 ) were collected and randomly divided into 2 group from June 2010 to July 2010.Groups 1(30 patients) used tube voltage as 120kv, Groups 2(30 patients) used tube voltage as 100kv. Both groups were used the improve retrospective ECG-gating of manual triggered scanning by 320 row CT.3. Results (1) There was significant difference of imaging quality between the 4 groups (P<0.05), And there was significant difference of imaging quality between groups 1 and the other groups (P<0.05) in automatic method. There was no significant difference of imaging quality between groups 1 and groups 5 (P>0.05). The mean great cardiac vein(GCV) CT value in groups 1 was (114.7±12.1) HU and (75.1±9.1) HU in the groups 5. There was significant difference between GCV CT value of the two groups (P<0.05). (2) The percentage of assessable coronary artery segments was 94.03% (615/654) in the groups 1, whereas 94.68% (605/639) in the groups 2. There was no significant difference of imaging quality between the two groups (P>0.05). The mean effective dosage (ED) in the groups 1 was (2.90±0.37) mSv and (10.33±1.65) mSv in the groups 2. There was significant difference between radiation dose of the two groups (P<0.05). (3) A total of 375 coronary artery segments were evaluated in groups 1 and 367 segments were evaluated in groups 2. There was no statistical difference in imaging quality between the two groups (P=0.373). The effective dose was (4.14±0.42)mSv in groups 1, (2.30±0.43)mSv in groups 2 (P<0.01).4. Conclusions Using the tube voltage as 100kV while using improve retrospective ECG-gating of manual triggered scanning by 320 row CT can obviously reduce the radiation dose for patients BMI within the normal range with no influence on image quality.PartⅡThe clinical value of 320 row CT in low-dose imaging technology of coronary artery1. 0bjective: To evaluate the accuracy and feasibility of 320 row CT in detecting coronary artery stenoses Comparsioned with coronary angiography.2. Methods: 160 patients with suspected coronary artery disease from April 2010 to July 2010 were studied with 320 row CT. 100 patients were male and 60 females, aged 29 to 89 years old, average 53.5 years old. 98 patients prior to examination of heart rate is 50 ~ 75 times / min, 62 patients were 75 to 88 times / min; 127 patients were in sinus rhythm, mean heart rate 70 beats / min. 16 patients also underwent conventional coronary angiography(CAG). With various reconstruction methods, Image quality was then analyzed,and the sensitivity, specificity, positive and negative predictive value of≥50% stenosis were calculated.3. ResuIts: The images were excellent(I, n=132, 82.5%), sufficient(Ⅱ,n=22, 13.75%) and non—diagnostic(Ⅲ, n=6, 3.75% ), respectively. Motion artifacts were found in 11 patients. The sensitivity, specificity, positive and negative predic1ive va1ue of the 320 row CT in detecting coronary artery stenosis≥50% was 97.67%, 98.48%, 93.33% and 98.48%, respectively.4. Conclusion The 320 row CT coronary angiography provides high sensitivity and specificity in detecting coronary artery stenosis.