Application of iterative reconstruction technique on dose reduction at body mass index-based CT coronary angiography

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 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). 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). 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. Key words: Coronary vessels; Cardiac imaging techniques; Image processing, computer-assisted; Radiation dosage; Image quality