Optimization of kV Selection on Third-generation High-pitch Dual-source Coronary CT Angiography Using Ultra-low Contrast Media Protocols in Patients with Body Mass Index between 20-30 kg/munder Automatic Tube Voltage Selection / 中国医学科学院学报

ABSTRACT

Objective To investigate the application of automatic tube voltage selection (CARE-kV)coronary CT angiography (CCTA)using ultra-low contrast media (CM)protocols in patients with body mass index (BMI)between 20 kg/mand 30 kg/mon third-generation dual-source CT (DSCT). Methods We prospectively included 134 consecutive patients with BMI between 20 kg/mand 30 kg/mwho underwent CARE-kV prospective high-pitch CCTA on third-generation DSCT using the ultra-low CM protocols and divided them into two groups according to the CARE-kV results:70 kV group(n=91)65 patients with normal BMI(20 kg/m≤BMI≤25 kg/m)and 26 patients with high BMI(25 kg/m<BMI≤30 kg/m);and 80 kV group(n=43)12 patients with normal BMI and 31 patients with high BMI. The 70 kV group and 80 kV group used the CM protocols of 18 ml(3.0 ml/s) and 21 ml(3.0 ml/s),respectively. The effective dose (ED),objective and subjective image quality (IQ),and results of patients in each group and subgroup were evaluated and compared.ResultsThe ED of 70 kV group was(0.24±0.04)mSv,which was 53% lower(H=3.37,P=0.02)than that of 80 kV group [(0.51±0.05)mSv]. No significant difference of CNR and SNR had been found in normal BMI patients(H=1.81,P=0.23)and high BMI patients (H=0.91,P=0.84)among 70 kV group and 80 kV group,as well as the subjective IQ in normal BMI patients(Z=0.79,P=0.76)and high BMI patients (Z=0.77,P=0.81)among 70 kV group and 80 kV group. Conclusion sWhen patients with BMI between 20 kg/mand 30 kg/mreceive CARE-kV prospective high-pitch CCTA on third-generation DSCT,the CARE-kV results for a portion of patients may be higher than other patients with the same BMI level,so as to guarantee the equivalent IQ. The CARE-kV can help to select the patients' optimal tube voltage value more accurately and reasonably.