title: Low tube voltage intermediate tube current liver MDCT: sinogram-affirmed iterative reconstruction algorithm for detection of hypervascular hepatocellular carcinoma.
abstract: OBJECTIVE
  The purpose of this study was to compare image quality and lesion detectability in the evaluation of hypervascular hepatocellular carcinoma (HCC) on low-tube-voltage half-dose liver CT scans subjected to sinogram-affirmed iterative reconstruction (SAFIRE) with the quality and detectability on full-dose scans reconstructed with filtered back projection (FBP).
  
  
  METHODS
  A total of 126 patients with suspected HCC who underwent liver CT including arterial phase scanning at 80 kVp in the dual-source mode (300 mAs for each tube) were included in the study. The half-dose arterial scans were reconstructed with FBP, iterative reconstruction in image space (IRIS), and five SAFIRE strengths (S1-S5) and were compared with full-dose virtual scans (600 mA) reconstructed with FBP. We assessed image noise, contrast-to-noise ratio (CNR) of the liver and blood vessels, and lesionto-liver CNR. Two radiologists evaluated image quality and lesion detectability attained with the different imaging sets.
  
  
  RESULTS
  Image noise on SAFIRE images was significantly lower than that on the other images, and the CNRs on SAFIRE images were higher than those on half-dose FBP images (p < 0.001). In addition, lesion-to-liver CNR on the half-dose S5 SAFIRE images was higher than on IRIS and full-dose FBP images (p < 0.05). Among the half-dose scans, SAFIRE images had significantly better image quality than FBP images (p < 0.05). Regarding lesion detection, half-dose SAFIRE images were better than half-dose FBP images and were comparable with full-dose FBP images (observer 1, 91.8% vs 96%; observer 2, 98% vs 98%; p > 0.05).
  
  
  CONCLUSIONS
  Performing half-dose 80-kVp liver CT with SAFIRE technique may increase image quality and afford comparable lesion detectability of hypervascular HCC at a reduced radiation dose compared with full-dose CT with FBP.
authors.affiliation: Department of Radiology and the Institute of Radiation Medicine, Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul, 110-744, Republic of Korea.
authors.forename: M Hye
authors.initials: MH
authors.lastname: Yu
authors.forename: Jeong Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Jeong-Hee
authors.initials: JH
authors.lastname: Yoon
authors.forename: Jee Hyun
authors.initials: JH
authors.lastname: Baek
authors.forename: Joon Koo
authors.initials: JK
authors.lastname: Han
authors.forename: Byung-Ihn
authors.initials: BI
authors.lastname: Choi
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Flohr
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000704:Analysis of Variance; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging*; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D008113:Liver Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D059629:Signal-To-Noise Ratio; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide