title: Spatial distribution of malignant tissue in gliomas: correlations of 11C-L-methionine positron emission tomography and perfusion- and diffusion-weighted magnetic resonance imaging.
abstract: BACKGROUND
  The prognosis of glioma patients is contingent on precise target selection for stereotactic biopsies and the extent of tumor resection. (11)C-L-methionine (MET) positron emission tomography (PET) demonstrates tumor heterogeneity and invasion with high diagnostic accuracy.
  
  
  OBJECTIVE
  To compare the spatial tumor distribution delineated by MET PET with that by perfusion- and diffusion-weighted magnetic resonance imaging (MRI), in order to understand the diagnostic value of these MRI methods, when PET is not available.
  
  
  METHODS
  Presurgical MET PET and MRI, including perfusion- and diffusion-weighted MRI, were acquired in 13 patients (7 high-grade gliomas, 6 low-grade gliomas). A quantitative volume of interest analysis was performed to compare the modalities objectively, supplemented by a qualitative evaluation that assessed the clinical applicability.
  
  
  RESULTS
  The inaccuracy of conventional MRI was confirmed (area under the curve for predicting voxels with high MET uptake = 0.657), whereas cerebral blood volume (CBV) maps calculated from perfusion data improved accuracy (area under the curve = 0.760). We considered CBV maps diagnostically comparable to MET PET in 5/7 cases of high-grade gliomas, but insufficient in all cases of low-grade gliomas when evaluated subjectively. Cerebral blood flow and apparent diffusion coefficient maps did not contribute to further accuracy.
  
  
  CONCLUSIONS
  Adding perfusion-weighted MRI to the presurgical protocol can increase the diagnostic accuracy of conventional MRI and is a simple and well-established method compared to MET PET. However, the definition of low-grade gliomas with subtle or no alterations on cerebral blood volume maps remains a diagnostic challenge for stand-alone MRI.
authors.affiliation: Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark Center of Functionally Integrative Neuroscience, Aarhus University Hospital, Aarhus, Denmark annatietze@gmail.com.
authors.forename: Anna
authors.initials: A
authors.lastname: Tietze
authors.affiliation: Center of Functionally Integrative Neuroscience, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Jens K
authors.initials: JK
authors.lastname: Boldsen
authors.affiliation: Center of Functionally Integrative Neuroscience, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Kim
authors.initials: K
authors.lastname: Mouridsen
authors.affiliation: Center of Functionally Integrative Neuroscience, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Lars
authors.initials: L
authors.lastname: Ribe
authors.affiliation: Department of Neurosurgery, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Suzan
authors.initials: S
authors.lastname: Dyve
authors.affiliation: Department of Neurosurgery, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Søren
authors.initials: S
authors.lastname: Cortnum
authors.affiliation: Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark Center of Functionally Integrative Neuroscience, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Leif
authors.initials: L
authors.lastname: Østergaard
authors.affiliation: Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Borghammer
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008715:Methionine / Q000031:analogs & derivatives*; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals
chemical_list: D019275:Radiopharmaceuticals; D008715:Methionine
keywords: CNS; PET; brain/brain stem; comparative study; perfusion- and diffusion-weighted magnetic resonance imaging; primary neoplasms