title: Combined Use of Automatic Tube Voltage Selection and Current Modulation with Iterative Reconstruction for CT Evaluation of Small Hypervascular Hepatocellular Carcinomas: Effect on Lesion Conspicuity and Image Quality.
abstract: OBJECTIVE
  To assess the lesion conspicuity and image quality in CT evaluation of small (≤ 3 cm) hepatocellular carcinomas (HCCs) using automatic tube voltage selection (ATVS) and automatic tube current modulation (ATCM) with or without iterative reconstruction.
  
  
  METHODS
  One hundred and five patients with 123 HCC lesions were included. Fifty-seven patients were scanned using both ATVS and ATCM and images were reconstructed using either filtered back-projection (FBP) (group A1) or sinogram-affirmed iterative reconstruction (SAFIRE) (group A2). Forty-eight patients were imaged using only ATCM, with a fixed tube potential of 120 kVp and FBP reconstruction (group B). Quantitative parameters (image noise in Hounsfield unit and contrast-to-noise ratio of the aorta, the liver, and the hepatic tumors) and qualitative visual parameters (image noise, overall image quality, and lesion conspicuity as graded on a 5-point scale) were compared among the groups.
  
  
  RESULTS
  Group A2 scanned with the automatically chosen 80 kVp and 100 kVp tube voltages ranked the best in lesion conspicuity and subjective and objective image quality (p values ranging from < 0.001 to 0.004) among the three groups, except for overall image quality between group A2 and group B (p = 0.022). Group A1 showed higher image noise (p = 0.005) but similar lesion conspicuity and overall image quality as compared with group B. The radiation dose in group A was 19% lower than that in group B (p = 0.022).
  
  
  CONCLUSIONS
  CT scanning with combined use of ATVS and ATCM and image reconstruction with SAFIRE algorithm provides higher lesion conspicuity and better image quality for evaluating small hepatic HCCs with radiation dose reduction.
authors.affiliation: Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province 450052, China.
authors.forename: Peijie
authors.initials: P
authors.lastname: Lv
authors.affiliation: Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province 450052, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province 450052, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Siemens Healthcare China, Beijing 100102, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Jia
authors.affiliation: Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province 450052, China.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Gao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging*; D003287:Contrast Media; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
chemical_list: D003287:Contrast Media
keywords: Automatic tube current modulation; Automatic tube voltage selection; Sinogram-affirmed iterative reconstruction; Small hepatocellular carcinoma