title: Focal liver lesions: breathhold gradient- and spin-echo T2-weighted imaging for detection and characterization.
abstract: OBJECTIVE
  To evaluate breathhold gradient- and spin-echo (GRASE) T2-weighted imaging for the detection and characterization of focal liver lesions.
  
  
  METHODS
  Two GRASE sequences with different echo times (75 and 90 msec, GRASE75 and GRASE90) were compared with respiratory-triggered fast spin-echo (SE) and breathhold fast SE in 64 patients with 103 malignant and 51 benign lesions. Compared with respiratory-triggered and breathhold fast SE, GRASE reduced scan time by 77% to 82% and 21% to 27%, respectively. Two independent readers evaluated image quality and reviewed 504 liver segments on a segment-by-segment basis. Observer performance was evaluated with receiver operating characteristic (ROC) curve analysis. The signal-to-noise ratio (SNR) of liver and spleen, and lesion-to-liver contrast-to-noise ratio (CNR) were also measured.
  
  
  RESULTS
  The overall quality of the GRASE images was higher than that of the respiratory-triggered and breathhold fast SE images, although signal inhomogeneities were more frequently observed with GRASE. No significant difference in the values of the area under the ROC curve (Az) for malignant lesion detection was found. The mean SNR and CNR were highest for respiratory-triggered fast SE.
  
  
  CONCLUSIONS
  T2-weighted breathhold GRASE has the potential to provide faster liver imaging.
authors.affiliation: Department of Radiology, Division of Magnetic Resonance Imaging, Thomas Jefferson University, Philadelphia, Philadelphia, Pennsylvania 19107, USA. yoshikawa0816@aol.com
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Donald G
authors.initials: DG
authors.lastname: Mitchell
authors.forename: Shozo
authors.initials: S
authors.lastname: Hirota
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohno
authors.forename: Jun
authors.initials: J
authors.lastname: Yoshigi
authors.forename: Takaki
authors.initials: T
authors.lastname: Maeda
authors.forename: Masahiko
authors.initials: M
authors.lastname: Fujii
authors.forename: Kazuro
authors.initials: K
authors.lastname: Sugimura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012372:ROC Curve