title: Perfusion-sensitive MRI of pilocytic astrocytomas: initial results.
abstract: OBJECTIVE
  To present the imaging and perfusion data obtained in nine patients with pilocytic astrocytomas (PA) and to discuss the original functional issues of this technique.
  
  
  METHODS
  Nine patients with pathologically proven PA underwent conventional and perfusion MR imaging. Various areas of relative cerebral blood volume (rCBV) within the tumors were obtained. The maximum rCBV ratios were identified and considered as representative of the tumor. The results were compared with the pathological findings.
  
  
  RESULTS
  In all patients, rCBV was <1.5 (mean 1) and the signal intensity curve overshot the baseline.
  
  
  CONCLUSIONS
  PA tend to have low rCBV values and a first-pass curve that crosses the baseline. These characteristics may be explained by the histological profile of the tumoral vascularity and are of relevance in the identification of these rare tumors.
authors.affiliation: Neuroradiology, Hôpital Michallon, Grenoble, France. SGrand@chu-grenoble.fr
authors.forename: Sylvie D
authors.initials: SD
authors.lastname: Grand
authors.forename: Stéphane
authors.initials: S
authors.lastname: Kremer
authors.forename: Irène M
authors.initials: IM
authors.lastname: Tropres
authors.forename: Dominique M
authors.initials: DM
authors.lastname: Hoffmann
authors.forename: Stephan J
authors.initials: SJ
authors.lastname: Chabardes
authors.forename: Virginie
authors.initials: V
authors.lastname: Lefournier
authors.forename: François R
authors.initials: FR
authors.lastname: Berger
authors.forename: Caroline
authors.initials: C
authors.lastname: Pasteris
authors.forename: Alexandre
authors.initials: A
authors.lastname: Krainik
authors.forename: Basile M
authors.initials: BM
authors.lastname: Pasquier
authors.forename: Michel
authors.initials: M
authors.lastname: Peoch
authors.forename: Jean François
authors.initials: JF
authors.lastname: Le Bas
mesh_terms: D000293:Adolescent; D000328:Adult; D001254:Astrocytoma / Q000175:diagnosis* / Q000503:physiopathology*; D001810:Blood Volume; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D002648:Child; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA