A feasibility study of 70 kV double low-dose coronary imaging technique in abdomen-fatty patients using dual-source CT.

Objective: To investigate the aplication of low contrast agent concentration and low tube voltage in coronary CTA on patients with high BMI (26kg/m28kg/m).

Methods: 60 patients with high BMI (26kg/m228kg/m) were randomly divided into two groups: double low group A (n=30, tube voltage = 70 KV), double low group B (n=30, tube voltage = 70 KV), processed by SAFIRE iterative reconstruction with 270 mgI/ml contrast agent. Conventional group a (n=30, tube voltage = 120 KV), conventional group b (n=30, tube voltage = 120 KV), with filtered back projection (FBP) and 370 mg I/ml contrast agent. the image excellent index (FOM), the effective radiation dose (ED), mean CT value, signal-to-noise ratio (SNR), and contrast-to-noise ratio(CNR) between corresponding groups were compared.

Result: There was no significant difference in subjective scores of coronary artery image quality between the two high BMI subgroups (P>0.05).The ED of group A (1.103±0.101 mSv) was significantly lower than that of group a (4.663±0.412 mSv) (P<0.001).There was no significant difference in mean CT value, SNR and CNR between the two subgroups (P>0.05).The image excellent index (FOM) of group A was higher than that of group a (P<0.05).The total iodine content and iodine injection rate in group A were lower than those in group a (P<0.001).The difference of subjective scores of coronary artery image quality between the two ultra-high subgroups was significant. The mean CT value, SNR and CNR of group B were lower than those of group b (P<0.05). The images of 14 patients in group B could not meet the diagnosis demand.

Conclusion: It is feasible to reduce the tube voltage to 70KV in patients with abdominal BMI with high BMI (26Kg/m28Kg/m), under the same conditions, the 70KV can not meet the daily diagnosis requirement.