[Application of adaptive statistical iterative reconstruction veo and 80 kv in renal computed tomography angiography]

Objective: To explore the application of adaptive statistical iterative reconstruction Veo (ASIR-V) and 80 kV in renal computed tomography angiography(CTA). Methods: Eighty patients with renal computed tomography angiography were prospectively collected from April 2018 to July 2018 in the Affiliated Hospital of Shaanxi University of Chinese Medicine and randomly divided into group A and group B. The patients in group A adopted tube voltage 120 kV and contrast agent concentration 600 mgI/kg and reconstructed with filtered back projection (FBP), while the patients in group B were scanned with tube voltage 80 kV and contrast agent concentration 350 mgI/kg and reconstructed with FBP and ASIR-V from 10% to 100% with 10% interval. The CT values and standard deviation (SD) of the right renal artery, left renal artery were measured respectively to calculate the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR).The image quality of renal CTA was subjectively scored by two experienced radiologists blindly using a 5-point criteria.The contrast agent,CT volume dose index(CTDI(vol)) and dose length product(DLP) in both groups were recorded and the effective radiation dose(ED) was calculated. Results: The ED ((2.11±0.19)mSv) and contrast agent ((21.9±3.0)g) in group B were 65.1% (P<0.05) and 42.2% (P<0.05) lower than those in group A ((6.04±1.89)mSv and (38.0±3.8)g).With the increase of ASIR-V percentage in group B, CT values showed no significant difference, SD values gradually decreased, SNR values and CNR values gradually increased.The CT values with different reconstruction algorithm showed no statistically significant difference (all P>0.05) between group A and group B. The SD values with 40%ASIR-V to 100%ASIR-V reconstruction in group B were significantly lower than those of group A (all P<0.05).The SNR values with 50% ASIR-V to 100% ASIR-V reconstruction and CNR values with 70%ASIR-V to 100%ASIR-V were significantly higher than those of group A(all P<0.5).Two radiologists had excellent consistency in subjective scores of image quality for renal CTA(all kappa>0.75, P<0.05). The subjective scores with 60% ASIR-V to 90% ASIR-V in group B were significantly higher than those in group A (P<0.05), of which 70%ASIR-V reconstruction achieved the highest subjective score for renal CTA. Conclusion: ASIR-V and 80 kV can significantly reduce radiation dose (about 65.1%) and contrast agent (about 42.2%) in renal CTA, ASIR-V reconstruction can significantly improve the image quality of renal CTA, of which 70% ASIR-V reconstruction achieved the best image quality in 80 kV renal CTA.