title: Comparison between in-phase and opposed-phase T1-weighted breath-hold FLASH sequences for hepatic imaging.
abstract: OBJECTIVE
  Our goal was to compare in-phase (IP) and opposed-phase (OP) sequences for GRE breath-hold hepatic imaging.
  
  
  METHODS
  Non-contrast-enhanced IP and OP GRE breath-hold images were obtained in 104 consecutive patients referred for abdominal MRI at 1.0 T. For both sequences, the TR, FA, matrix, FOV, slice thickness, interslice gap, and measurements were kept constant. Images were compared quantitatively [liver/spleen and liver/lesion signal difference/noise ratio, (SD/N)] and qualitatively (artifacts, lesion detection and conspicuity, and intrahepatic anatomy).
  
  
  RESULTS
  There was no statistically significant difference when comparing IP and OP sequences for liver/spleen and liver/lesion SD/N or for the qualitative parameters. In patients with fatty infiltration, the OP sequences yielded substantially lower values for liver/spleen and liver/lesion SD/N (0.9 and -1.2, respectively) than the IP sequences (20 and 17, respectively). Furthermore, in several cases with fatty infiltration, many more lesions were identified using IP images.
  
  
  CONCLUSIONS
  The use of IP and OP GRE sequences provides complementary diagnostic information. Focal liver lesions may be obscured in the setting of fatty infiltration if only OP sequences are employed. A complete assessment of the liver with MR should include both IP and OP imaging.
authors.affiliation: Department of Radiology, New York University Medical Center, New York, NY 10016, USA.
authors.forename: N M
authors.initials: NM
authors.lastname: Rofsky
authors.forename: J C
authors.initials: JC
authors.lastname: Weinreb
authors.forename: M M
authors.initials: MM
authors.lastname: Ambrosino
authors.forename: J
authors.initials: J
authors.lastname: Safir
authors.forename: G
authors.initials: G
authors.lastname: Krinsky
mesh_terms: D005260:Female; D006801:Humans; D008099:Liver / Q000473:pathology*; D008107:Liver Diseases / Q000175:diagnosis; D008113:Liver Neoplasms / Q000175:diagnosis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis