title: Implications of post-gadolinium MRI results in 13 cases with posterior reversible encephalopathy syndrome.
abstract: BACKGROUND
  There is a relative lack of definitive information about the contrast-enhancement characteristics of lesions in posterior reversible encephalopathy syndrome (PRES).
  
  
  OBJECTIVE
  Evaluation of contrast-enhanced MRI findings in PRES with a special emphasis on pathophysiology of post-gadolinium behavior of these lesions.
  
  
  METHODS
  Contrast-enhanced 1.5 T MRI findings and relevant clinical data of the patients were retrospectively reviewed on 13 cases (six males, seven females; age range: 22-78; mean age 47). Although fluid attenuated inversion recovery (FLAIR) and diffusion-weighted MR images were considered for identification of the entity, primarily post-contrast T1-weighted MR images were searched for traces of enhancement in the lesions.
  
  
  RESULTS
  No definitely enhancing lesion was identified in the MR images obtained in 6-48 h after onset of symptoms (mostly headaches, seizures and cortical visual field deficits) in this series. Severity of disease indicated by small hemorrhages, confluence of lesions or progression to cytotoxic edema did not seem to alter this result. Typical lesion characteristics were consistent with vasogenic edema on FLAIR and diffusion MR images. Acute elevation of blood pressure on chronic hypertensive background was responsible in four, eclampsia in three, uremia with blood pressure fluctuations in three, and cyclosporine-toxicity in three cases.
  
  
  CONCLUSIONS
  Although occasional enhancing brain lesions have been reported in the literature on PRES, contrast-enhancement of lesions may be a factor of scan timing and underlying etiology. Prospective studies with larger series on PRES are required for better evaluation of contrast-enhancement in MRI with respect to scan timing, which in turn may help understand its pathophysiology better.
authors.affiliation: Department of Radiology, Gulhane Military Medical Academy & Medical Faculty, Ankara 06018, Turkey. sugurel@gata.edu.tr
authors.forename: Mehmet Sahin
authors.initials: MS
authors.lastname: Ugurel
authors.forename: Minako
authors.initials: M
authors.lastname: Hayakawa
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000098:blood supply*; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D020343:Hypertensive Encephalopathy / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013577:Syndrome
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA