title: MR imaging of hemorrhagic brain lesions: a comparison of dual-echo gradient- and spin-echo and fast spin-echo techniques.
abstract: OBJECTIVE
  Our objective was to assess the usefulness of the dual-echo gradient- and spin-echo (GRASE) technique in revealing acute hemorrhagic brain lesions and compare GRASE and fast spin-echo techniques for revealing acute hemorrhagic lesions and image artifacts.
  
  
  METHODS
  Thirty-two consecutive patients with acute intracranial hemorrhage underwent dual-echo GRASE (TEeff1/TEeff2, 35/85) and fast spin-echo (25/110) imaging. The techniques were matched for TR (3032 msec), spatial resolution, and acquisition time. Two neuroradiologists reviewed the images independently, documenting the number, size (<1, >1, or 1 cm in diameter), location, and signal characteristics (hypointense versus hyperintense compared with brain) of detectable lesions. These observers also compared matched T2- and proton density-weighted GRASE and fast spin-echo images for paramagnetic lesion conspicuity, diamagnetic susceptibility artifacts, chemical shift artifacts along the phase- and frequency-encoding directions, and artifactual CSF hyperintensity in the thin curvilinear cortical sulci and the Virchow-Robin spaces on only the proton density-weighted images.
  
  
  RESULTS
  The average number and conspicuity of dark (paramagnetic) lesions were significantly greater on GRASE than on fast spin-echo images (p < .05 and p < .001, respectively). We found no significant difference in the average number of bright lesions revealed by either technique (p > .1). Chemical shift artifacts along the phase-encoding directions were more prominent on GRASE than on fast spin-echo imaging. Chemical shift artifacts along the frequency-encoding directions and artifactual CSF hyperintensity were more prominent on fast spin-echo than on GRASE imaging. No visually apparent difference was found in the degree of diamagnetic susceptibility artifacts seen with the two techniques.
  
  
  CONCLUSIONS
  Dual-echo GRASE imaging can be helpful in the examination of patients with suspected acute brain hemorrhage.
authors.affiliation: Department of Radiology, Boston University School of Medicine, Boston Medical Center, MA 02118, USA.
authors.forename: E R
authors.initials: ER
authors.lastname: Melhem
authors.forename: R T
authors.initials: RT
authors.lastname: Patel
authors.forename: R E
authors.initials: RE
authors.lastname: Whitehead
authors.forename: R G
authors.initials: RG
authors.lastname: Bhatia
authors.forename: D T
authors.initials: DT
authors.lastname: Rockwell
authors.forename: H
authors.initials: H
authors.lastname: Jara
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D001921:Brain / Q000473:pathology*; D002543:Cerebral Hemorrhage / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies