Abstract：Objective To explore the feasibility of iterative reconstruction technique on dose reduction at body mass index (BMI)-based CT coronary angiography (CTCA) with retrospective gating in 128 slice spiral CT.Methods From December 2013 to August 2014, 90 patients in Dongchangfu People′s Hospital who were suspected coronary artery disease were selected. All subjects were diagnosed as coronary heart disease. The selected patients had no history of allergy to iodine contrast agent and the other disease that is not suitable for CTCA test. According to the different BMI of CTCA subjects, the subjects were divided into 3 groups: group A, 28 kg/m2≤BMI≤31 kg/m2; group B, 24 kg/m2<BMI<28 kg/m2; group C, 21 kg/m2≤BMI≤24 kg/m2. The number of patients in each group was 30. The tube current was set as 800 mAs, 600 mAs, and 400 mAs for group A, B and C, respectively. The tube voltages of three groups are all 120 kV. Four series of images were reconstructed with filtered back project(FBP), iDose4-3, iDose4-5, iDose4-7 for each subject after used retrospectively ECG-gated CTCA technology to scan. The objective noise and subjective image quality were assessed. Two doctors who have 10 years experience in diagnosis assessed subjective image quality (the vascular diameter>1.5 mm) using 15 sections method and the four point method to evaluate coronary artery. The region of interest of three group′s reconstructive images chosen from the fat density area in front of the ascending aorta which covers an area of about 14.5 mm2 was measured as noise value and compared between them. Scan length and radiation dose index were given by the machine automatically.Results All the groups were shown that the maximum number of segments over 3 scores level was in the iDose4-3 and iDose4-5 reconstructive image groups, and the maximum number of segments under 2 score level was in the FBP and iDose4-5 reconstructive image groups. The difference was statistical significance between the group FBP or iDose4-7 and the group iDose4-3 or iDose4-5(all P values<0.05), and there was no statistical difference between neither group iDose4-3 and iDose4-5 nor group FBP and iDose4-7(all P values>0.05). Compared with the group FBP, the average objective noise of the group iDose4-3, iDose4-5, and iDose4-7 reduced 29.96%, 51.56% and 69.76%, respectively. The difference of noise value was all statistical significance between the groups of different patients reconstruction image (all P values< 0.05). And all of the difference was no statistical significance between the same reconstruction images (all P values> 0.05). Compared with group A, the effective radiation dose of group B and group C was reduced by 25.83% and 25.83%, respectively.Conclusions The iterative reconstruction algorithm can effectively reduce the noise, combined with a body mass index can effectively reduce the radiation dose, improve the quality of image.
张微晗. 体质量指数结合迭代重建算法在螺旋CT冠状动脉成像中的应用[J]. 中华解剖与临床杂志, 2015, 20(4): 325-329.
Zhang Weihan.. Application of iterative reconstruction technique on dose reduction at body mass index-based CT coronary angiography. Chinese Journal of Anatomy and Clinics, 2015, 20(4): 325-329.
Lee CI, Haims AH, Monico EP, et al. Diagnostic CT scans: assessment of patient, physician, and radiologist awareness ofradiation dose and possible risks[J]. Radiology, 2004, 231(2): 393-398.
[2]
Berrington de González A, Darby S. Risk of cancer from diagnostic X-rays: estimates for the UK and 14 other countries[J]. Lancet, 2004, 363(9406): 345-351.
[3]
European Study Group of Radiologist and Physicians. European guidelines on quality criteria for computed tomography[J/OL]. [2013-05-01]. http: //w3. tue. nl/fileadmin/sbd/Documenten/Leergang/BSM//European_Guidelines_Quality_Criteria_Computed_Tomography _Eur_l6252. pdf.
[4]
Hur G, Hong SW, Kim SY, et al. Uniform image quality achieved by tube current modulation using SD of attenuation in coronary CT angiography[J]. AJR Am J Roentgenol, 2007, 189(1): 188-196.
Hosch W, Stiller W, Mueller D,et al. Reduction of radiation exposure and imp-roviment of image quality with BMI-adapted prospective cardiac computed tomography and iterative reconstruction[J]. Eur J Radiol, 2012, 81(11): 3568-3576.
[7]
Leipsic J, Labounty TM, Heilbron B, et al. Estimated radiation dose reduction using adaptive statistcal iterative reconstruction in coronary CT angiography: the ERASIR atudy[J]. AJR Am J Roentgenol, 2010, 195(3): 655-660.
[8]
Park EA, Lee W, Kim KW, et al. Iterative reconstruction of dualsource coronary CT angiography: assessment of image quality and radiation dose[J]. Int J Cardiovasc Imaging, 2012, 28(7): 1775-1786.
2015, Vol. 20 
