title: Detection of hepatocellular carcinoma using double-echo FLASH sequence during the hepatic arterial phase.
abstract: OBJECTIVE
  The purpose of this study was to compare the performance of in-phase and opposed-phase gradient-recalled echo (GRE) pulse sequences in paramagnetic contrast-enhanced magnetic resonance (MR) imaging of hepatocellular carcinomas (HCCs) during the hepatic arterial phase.
  
  
  METHODS
  Thirty-four patients with 84 lesions with known or suspected HCCs, nine of whom had a fatty liver, were examined with double-echo GRE techniques under 1.5T before and 30 s after injection of gadopentenate dimeglumine at a dose of 0.1 mmol/kg. Echo times were 2.4 ms (opposed phase) and 5.0 ms (in phase). Contrast enhancement of the HCC detected in both in-phase and opposed-phase images was evaluated. The liver signal-to-noise ratio (SNR), lesion-liver contrast-to-noise ratio (CNR), and enhancement ratio (ER) were calculated for the largest lesion of each patient.
  
  
  RESULTS
  In dynamic gadolinium-enhanced images of the 84 HCCs, 81 (96.4%) were detected in both in-phase and opposed-phase images, two (2.4%) were detected in only in-phase images, and one (1.2%) was detected only in opposed-phase images. The liver SNR, CNR, and ER were 46.7+/-16.1, 15.2+/-10.3, and 0.637+/-0.268 for in-phase images, and 48.9+/-16.9, 16.3+/-11.8, and 0.647+/-0.309 for opposed-phase images, respectively. In patients with a fatty liver, the SNR, CNR, and ER were 46.0+/-18.1, 21.7+/-17.9, and 0.525+/-0.231 for in-phase images, and 44.3+/-18.7, 26.0+/-21.3, and 0.793+/-0.124 for opposed-phase images, respectively. No significant statistical differences were found between the in-phase and opposed-phase images.
  
  
  CONCLUSIONS
  Opposed-phase GRE imaging is equivalent to in-phase GRE sequences in patients with or without fatty liver for detection of HCC in dynamic gadolinium-enhanced images.
authors.affiliation: Department of Radiology, Minamata City Hospital, Kumamoto, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Namimoto
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Yamashita
authors.forename: Kazuo
authors.initials: K
authors.lastname: Awai
authors.forename: Akihiko
authors.initials: A
authors.lastname: Arakawa
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Nakayama
authors.forename: Shoji
authors.initials: S
authors.lastname: Morishita
authors.forename: Yuhshi
authors.initials: Y
authors.lastname: Araki
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000175:diagnosis*; D003287:Contrast Media; D005234:Fatty Liver / Q000175:diagnosis; D005260:Female; D019786:Gadolinium DTPA; D006499:Hepatic Artery; D006801:Humans; D008113:Liver Neoplasms / Q000098:blood supply / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D018709:Statistics, Nonparametric
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA