title: Diffusion-weighted MR imaging of intracerebral hemorrhage.
abstract: OBJECTIVE
  To document the signal characteristics of intracerebral hemorrhage (ICH) at evolving stages on diffusion-weighted images (DWI) by comparison with conventional MR images.
  
  
  METHODS
  In our retrospective study, 38 patients with ICH underwent a set of imaging sequences that included DWI, T1-and T2-weighted imaging, and fluid-attenuated inversion recovery (FLAIR). In 33 and 10 patients, respectively, conventional and echo-planar T2* gradient-echo images were also obtained. According to the time interval between symptom onset and initial MRI, five stages were categorized: hyperacute (n=6); acute (n=7); early subacute (n=7); late subacute (n=10); and chronic (n=8). We investigated the signal intensity and apparent diffusion coefficient (ADC) of ICH and compared the signal intensities of hematomas at DWI and on conventional MR images.
  
  
  RESULTS
  DWI showed that hematomas were hyperintense at the hyperacute and late subacute stages, and hypointense at the acute, early subacute and chronic stages. Invariably, focal hypointensity was observed within a hyperacute hematoma. At the hyperacute, acute and early subacute stages, hyperintense rims that corresponded with edema surrounding the hematoma were present. The mean ADC ratio was 0.73 at the hyperacute stage, 0.72 at the acute stage, 0.70 at the early subacute stage, 0.72 at the late subacute stage, and 2.56 at the chronic stage.
  
  
  CONCLUSIONS
  DWI showed that the signal intensity of an ICH may be related to both its ADC value and the magnetic susceptibility effect. In patients with acute stroke, an understanding of the characteristic features of ICH seen at DWI can be helpful in both the characterization of intracranial hemorrhagic lesions and the differentiation of hemorrhage from ischemia.
authors.affiliation: Department of Diagnostic Radiology, Samsung Medical Center, Sungkyun-kwan University School of Medicine, Seoul, Korea.
authors.forename: B K
authors.initials: BK
authors.lastname: Kang
authors.forename: D G
authors.initials: DG
authors.lastname: Na
authors.forename: J W
authors.initials: JW
authors.lastname: Ryoo
authors.forename: H S
authors.initials: HS
authors.lastname: Byun
authors.forename: H G
authors.initials: HG
authors.lastname: Roh
authors.forename: Y S
authors.initials: YS
authors.lastname: Pyeun
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D002543:Cerebral Hemorrhage / Q000175:diagnosis*; D002908:Chronic Disease; D004058:Diffusion; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012815:Signal Processing, Computer-Assisted