Preliminary study of 80 kVp CT pulmonary angiography with ASIR using 20 ml of contrast agent

HE Lin; YIN Xi; WANG Chengwei; WANG Zhengguo

Abstract：Objective To evaluate the feasibility of 80 kVp and 20 ml of contrast agent in CT pulmonary angiography ( CTPA) with spectral CT using ASIR reconstruction .Methods A total of 60 patients with suspected pulmonary embolism ( PE) under-went CTPA.They were randomly divided into 2 groups.Group A received 60 ml (370 mgI/ml) lopamidol at 120 kVp and FBP reconstruction.Group B were scanned with 80 kVp after injecting 20 ml (370 mgI/ml) lopamidol and 50%ASIR reconstruction. Independent t-test was used to compare the CT values , image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), volume CT dose index (CTDIvol), dose length product (DLP) and effective dose (ED).Mann-Whitney U test was used to com-pare the image quality score of the two groups .Results The CT values of pulmonary arteries , SNR, CNR in group B were higher than those of group A (all P <0.05).The CT CTDIvol, DLP, ED in group B were lower than those of group A( all P <0.05). There was no significant difference in image noise , subjective image quality between two groups ( P >0.05).Conclusion 80 kVp and 20 ml of contrast agent in CTPA with spectral CT using ASIR reconstruction can provide high quality image , which can meet clinical diagnostic need , the radiation dose and contrast medium volume could be decreased .