title: Comparison of in-phase and out-of-phase gradient recalled echo T1-weighted pulse sequence for MR imaging of malignant liver masses following administration of paramagnetic gadolinium-chelate.
abstract: BACKGROUND
  The purpose of this study was to compare the performance of in-phase and out-of-phase gradient recalled echo (GRE) pulse sequences on paramagnetic contrast-enhanced magnetic resonance (MR) imaging of malignant liver lesions.
  
  
  METHODS
  Fifty patients (27 women, 23 men; mean age = 50 +/- 27 years) with known or suspected focal liver lesions, nine of whom had a fatty liver, were examined at 1.5 T before and 60 min after injection of gadobenate dimeglumine at a dose of 0.05 or 0.1 mmol/kg using two GRE techniques: echo time of 2.3 ms (out-of-phase) or 4.6 ms (in-phase). Liver signal-to-noise ratio (SNR) and lesion-liver contrast-to-noise ratio (CNR) were calculated.
  
  
  RESULTS
  In patients with a nonfatty liver, liver SNR increased from 26 +/- 9 to 41 +/- 17 on in-phase images and from 28 +/- 8 to 45 +/- 14 on out-of-phase images. In patients with a fatty liver, in-phase images provided significantly higher (p < 0.01) liver SNR than did out-of-phase images predose (34 +/- 8 on in-phase vs. 21 +/- 8 on out-of-phase) and postdose (44 +/- 13 on in-phase vs. 33 +/- 14 on out-of-phase). In patients with a nonfatty liver, lesion-liver CNR was similar on in-phase and out-of-phase images, predose and postdose. In patients with fatty liver, lesion-liver CNR was significantly (p < 0.01) lower on out-of-phase images on predose and postdose images.
  
  
  CONCLUSIONS
  In-phase GRE imaging is recommended for imaging focal liver lesions on paramagnetic contrast-enhanced MR imaging in patients with fatty infiltration of the liver.
authors.affiliation: Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 32 Fruit Street, Boston, MA 02114, USA.
authors.forename: J
authors.initials: J
authors.lastname: Petersein
authors.forename: W
authors.initials: W
authors.lastname: Schima
authors.forename: S
authors.initials: S
authors.lastname: Saini
authors.forename: W
authors.initials: W
authors.lastname: Mayo-Smith
authors.forename: P F
authors.initials: PF
authors.lastname: Hahn
authors.forename: K E
authors.initials: KE
authors.lastname: Tanabe
authors.forename: A L
authors.initials: AL
authors.lastname: Warshaw
authors.forename: C F
authors.initials: CF
authors.lastname: del Castillo
authors.forename: B
authors.initials: B
authors.lastname: Hamm
authors.forename: P R
authors.initials: PR
authors.lastname: Mueller
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005234:Fatty Liver / Q000150:complications / Q000175:diagnosis; D005260:Female; D005682:Gadolinium; D006801:Humans; D008099:Liver / Q000473:pathology; D008113:Liver Neoplasms / Q000150:complications / Q000175:diagnosis* / Q000556:secondary; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives*; D008875:Middle Aged; D009942:Organometallic Compounds
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine; D005682:Gadolinium