title: Intra-lesional spatial correlation of static and dynamic FET-PET parameters with MRI-based cerebral blood volume in patients with untreated glioma.
abstract: OBJECTIVE
  18F-fluorethyltyrosine-(FET)-PET and MRI-based relative cerebral blood volume (rCBV) have both been used to characterize gliomas. Recently, inter-individual correlations between peak static FET-uptake and rCBV have been reported. Herein, we assess the local intra-lesional relation between FET-PET parameters and rCBV.
  
  
  METHODS
  Thirty untreated glioma patients (27 high-grade) underwent simultaneous PET/MRI on a 3 T hybrid scanner obtaining structural and dynamic susceptibility contrast sequences. Static FET-uptake and dynamic FET-slope were correlated with rCBV within tumour hotspots across patients and intra-lesionally using a mixed-effects model to account for inter-individual variation. Furthermore, maximal congruency of tumour volumes defined by FET-uptake and rCBV was determined.
  
  
  RESULTS
  While the inter-individual relationship between peak static FET-uptake and rCBV could be confirmed, our intra-lesional, voxel-wise analysis revealed significant positive correlations (median r = 0.374, p < 0.0001). Similarly, significant inter- and intra-individual correlations were observed between FET-slope and rCBV. However, rCBV explained only 12% of the static and 5% of the dynamic FET-PET variance and maximal overlap of respective tumour volumes was 37% on average.
  
  
  CONCLUSIONS
  Our results show that the relation between peak values of MR-based rCBV and static FET-uptake can also be observed intra-individually on a voxel basis and also applies to a dynamic FET parameter, possibly determining hotspots of higher biological malignancy. However, just a small part of the FET-PET signal variance is explained by rCBV and tumour volumes determined by the two modalities showed only moderate overlap. These findings indicate that FET-PET and MR-based rCBV provide both congruent and complimentary information on glioma biology.
authors.affiliation: Department of Neuroradiology, Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany. jens.goettler@tum.de.|TUM Neuroimaging Center (TUM-NIC), Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany. jens.goettler@tum.de.
authors.forename: Jens
authors.identifier: http://orcid.org/0000-0002-5746-2156
authors.initials: J
authors.lastname: Göttler
authors.affiliation: Department of Nuclear Medicine, Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Lukas
authors.affiliation: Department of Neuroradiology, Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Kluge
authors.affiliation: Department of Neuroradiology, Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Kaczmarz
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Gempt
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Ringel
authors.affiliation: Department of Nuclear Medicine, Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany.
authors.forename: Mona
authors.initials: M
authors.lastname: Mustafa
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Meyer
authors.affiliation: Department of Neuroradiology, Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany.
authors.forename: Claus
authors.initials: C
authors.lastname: Zimmer
authors.affiliation: Department of Nuclear Medicine, Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Schwaiger
authors.affiliation: TUM Neuroimaging Center (TUM-NIC), Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany.|Department of Nuclear Medicine, Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany.|Department of Nuclear Medicine, Klinikum Bayreuth, Preuschwitzer Str. 101, 95445, Bayreuth, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Förster
authors.affiliation: Department of Neuroradiology, Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany.|TUM Neuroimaging Center (TUM-NIC), Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Preibisch
authors.affiliation: Department of Nuclear Medicine, Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Pyka
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000000981:diagnostic imaging*; D002533:Cerebral Angiography; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging*; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D014443:Tyrosine / Q000031:analogs & derivatives
chemical_list: D019275:Radiopharmaceuticals; C545932:(18F)fluoroethyltyrosine; D014443:Tyrosine
keywords: 18F-fluorethyltyrosine-PET; CBV; DSC MRI; Glioma