title: Prediction of hemorrhagic transformation in acute ischemic stroke: role of diffusion-weighted imaging and early parenchymal enhancement.
abstract: OBJECTIVE
  MR imaging may help in predicting hemorrhagic transformation (HT) in acute ischemic stroke. Our purpose was to determine whether the lesion volumes on diffusion-weighted (DW) imaging, apparent diffusion coefficient (ADC) values, and early parenchymal enhancement are predictive of HT and to investigate the mechanism of the enhancement.
  
  
  METHODS
  We retrospectively examined 55 patients with acute ischemic stroke who underwent gadolinium-enhanced MR imaging within 6 hours of symptom onset and follow-up CT or MR imaging within 72 hours. Intravenous thrombolysis was performed in 15 patients. DW imaging lesion volumes and ADC values were compared between patients with and those without HT. ADCs and perfusion parameters were compared between lesions with and those without parenchymal enhancement.
  
  
  RESULTS
  Nineteen (34.5%) patients had HT (14 with hemorrhagic infarction, five with parenchymal hematoma). Patients with HT had decreased mean ADCs and large lesion volumes on DW imaging, but differences were not significant (P > .05). HT occurred in five patients (100%) with parenchymal enhancement, which corresponded to the site of HT. In enhancing lesions, the ADC ratio (0.76 +/- 0.06) was slightly higher and the delay in time to peak (0.10 +/- 2.79) was less than respective values in the rest of the ischemic lesion (0.66 +/- 0.06 and 8.79 +/- 4.86, respectively; P = .068).
  
  
  CONCLUSIONS
  Early parenchymal enhancement is highly specific for HT and may be associated with early reperfusion and damage to the blood-brain barrier in ischemic tissue. DW imaging lesion volumes and ADC values had no strong relationship with HT.
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Eung Yeop
authors.initials: EY
authors.lastname: Kim
authors.forename: Dong Gyu
authors.initials: DG
authors.lastname: Na
authors.forename: Sam Soo
authors.initials: SS
authors.lastname: Kim
authors.forename: Kwang Ho
authors.initials: KH
authors.lastname: Lee
authors.forename: Jae Wook
authors.initials: JW
authors.lastname: Ryoo
authors.forename: Ho Kyun
authors.initials: HK
authors.lastname: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000150:complications* / Q000175:diagnosis*; D002543:Cerebral Hemorrhage / Q000209:etiology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007089:Image Enhancement; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D020521:Stroke / Q000150:complications* / Q000175:diagnosis*