title: Double-low protocol for hepatic dynamic CT scan: Effect of low tube voltage and low-dose iodine contrast agent on image quality.
abstract: The radiation-induced carcinogenesis from computed tomography (CT) and iodine contrast agent induced nephropathy has attracted international attention. The reduction of the radiation dose and iodine intake in CT scan is always a direction for researchers to strive. The purpose of this study was to evaluate the feasibility of a "double-low" (i.e., low tube voltage and low-dose iodine contrast agent) scanning protocol for dynamic hepatic CT with the adaptive statistical iterative reconstruction (ASIR) in patients with a body mass index (BMI) of 18.5 to 27.9 kg/m.A total of 128 consecutive patients with a BMI between 18.5 and 27.9 kg/m were randomly assigned into 3 groups according to tube voltage, iodine contrast agent, and reconstruction algorithms. Group A (the "double-low" protocol): 100 kVp tube voltage with 40% ASIR, iodixanol at 270 mg I/mL, group B: 120 kVp tube voltage with filtered back projection (FBP), iodixanol at 270 mg I/ mL, and group C: 120 kVp tube voltage with FBP, ioversol at 350 mg I/ mL.The volume CT dose index (CTDIvol) and effective dose (ED) in group A were lower than those in group B and C (all P < 0.01). The iodine intake in group A was decreased by approximately 26.5% than group C, whereas no statistical difference was observed between group A and B (P > 0.05). There was no significant difference of the CT values between group A and C (P > 0.05), which both showed higher CT values than that in group B (P < 0.001). However, no statistic difference was observed in the contrast-to-noise ratio (CNR), the signal-to-noise ratio (SNR), and image-quality scores among the 3 groups (all P > 0.05). Near-perfect consistency of the evaluation for group A, B, and C (Kenall's W = 0.921, 0.874, and 0.949, respectively) was obtained by the 4 readers with respect to the overall image quality.These results suggested that the "double-low" protocol with ASIR algorithm for multi-phase hepatic CT scan can dramatically decrease radiation dose and iodine intake with adequate image quality in patients with BMI of 18.5 to 27.9 kg/m.
authors.affiliation: aDepartment of Radiology, Affiliated Hospital of Xuzhou Medical University bSchool of Medical Imaging, Xuzhou Medical University, Xuzhou cDepartment of Oncology, Zhongnan Hospital of Wuhan University, Wuhan dGE Life Science, Beijing, P. R. China.
authors.forename: Xiuli
authors.initials: X
authors.lastname: Zhang
authors.forename: Shaodong
authors.initials: S
authors.lastname: Li
authors.forename: Wenlou
authors.initials: W
authors.lastname: Liu
authors.forename: Ning
authors.initials: N
authors.lastname: Huang
authors.forename: Jingjing
authors.initials: J
authors.lastname: Li
authors.forename: Li
authors.initials: L
authors.lastname: Cheng
authors.forename: Kai
authors.initials: K
authors.lastname: Xu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002985:Clinical Protocols; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007455:Iodine / Q000008:administration & dosage*; D008099:Liver / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014283:Triiodobenzoic Acids / Q000008:administration & dosage*
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; D007455:Iodine; C044834:iodixanol