Value of the deep learning image reconstruction algorithm combined with low-kV technique in improving small vessel display level at routine abdominal contrast enhanced CT imaging / 中华放射学杂志

ABSTRACT

Objective:To evaluate the presentation of small arteries in abdominal contrast-enhanced CT late-arterial images using the deep learning image reconstruction (DLIR) combined with low tube voltage (kV) technique relative to the adaptive statistical iterative reconstruction V (ASiR-V) algorithm.Methods:Patients who were admitted to Peking University People′s Hospital from December 2021 to January 2022 and needed to be screened for abdominal diseases and receive abdominal and pelvic contrast-enhanced CT scan were prospectively collected. The patients were divided into low-voltage (LV) with 80 kV and high-voltage (HV) with 120 kV groups. According to two different reconstruction algorithms, each group was further divided into DLIR-H (D) subgroup and ASiR-V 50% (A) subgroup. The automatic tube current adjustment technique was used for CT enhanced scanning of patients, and the noise index value was uniformly set to 9. Subjective and objective evaluations were performed on the late-arterial images with a constructed slice thickness of 0.625 mm, and the radiation doses were recorded.Results:A total of 168 patients were included, including 76 males and 92 females, aged 18-85 (53±15) years old, body mass index (24±3) kg/m 2; 91 patients in the LV group and 77 in the HV group. The CT values of the aorta and common hepatic artery in the LV group were significantly higher than those in the HV group ( t=-14.20, P<0.001; t=-0.95, P<0.001). When the tube voltage was the same, the late-arterial image noise in subgroup D was significantly lower than that in subgroup A, and the signal to noise ratio (SNR) and contrast to noise ratio (CNR) of the liver, aorta and common hepatic artery were significantly higher than those in subgroup A (all P<0.001). The SNR and CNR of the aorta and common hepatic artery in the LV-D subgroup were significantly better than those in the LV-A, HV-D, and HV-A subgroups (all P<0.001). In the subjective evaluation of abdominal vascular display, the special resolution of the common hepatic artery, inferior mesenteric artery and the edge of the ascending branch of the left colic artery, and the contrast of the ascending branch of the left colic artery in the LV-D subgroup were significantly better than those of the LV-A, HV-D, and HV-A subgroups ( P<0.05). Moreover, the presentation rate of margin artery of splenic region (54.9%, 50/91) in the LV-D subgroup was significantly higher than those in the HV-D subgroup (24.7%, 19/77) and HV-A subgroup (32.5%, 25/77) (adjusted P<0.05). There was no significant difference in the radiation doses between LV and HV groups [(4.91±1.97) mSv vs (5.43±1.78) mSv, P>0.05]. Conclusion:The contrast-enhanced CT scan of abdomen with low tube voltage combined with DLIR algorithm can effectively improve the display level of the ascending vessel of left colonic artery from the inferior mesenteric artery and the margin artery, which brings more possibilities for the evaluation of similar small blood vessels.