title: TSPO Imaging in Glioblastoma Multiforme: A Direct Comparison Between 123I-CLINDE SPECT, 18F-FET PET, and Gadolinium-Enhanced MR Imaging.
abstract: Here we compare translocator protein (TSPO) imaging using 6-chloro-2-(4'-(123)I-iodophenyl)-3-(N,N-diethyl)-imidazo[1,2-a]pyridine-3-acetamide SPECT ((123)I-CLINDE) and amino acid transport imaging using O-(2-(18)F-fluoroethyl)-l-tyrosine PET ((18)F-FET) and investigate whether (123)I-CLINDE is superior to (18)F-FET in predicting progression of glioblastoma multiforme (GBM) at follow-up.
  
  
  METHODS
  Three patients with World Health Organization grade IV GBM were scanned with (123)I-CLINDE SPECT, (18)F-FET PET, and gadolinium-enhanced MR imaging. Molecular imaging data were compared with follow-up gadolinium-enhanced MR images or contrast-enhanced CT scans.
  
  
  RESULTS
  The percentage overlap between volumes of interest (VOIs) of increased (18)F-FET uptake and (123)I-CLINDE binding was variable (12%-42%). The percentage overlap of MR imaging baseline VOIs was greater for (18)F-FET (79%-93%) than (123)I-CLINDE (15%-30%). In contrast, VOIs of increased contrast enhancement at follow-up compared with baseline overlapped to a greater extent with baseline (123)I-CLINDE VOIs than (18)F-FET VOIs (21% vs. 8% and 72% vs. 55%).
  
  
  CONCLUSIONS
  Our preliminary results suggest that TSPO brain imaging in GBM may be a useful tool for predicting tumor progression at follow-up and may be less susceptible to changes in blood-brain barrier permeability than (18)F-FET. Larger studies are warranted to test the clinical potential of TSPO imaging in GBM, including presurgical planning and radiotherapy.
authors.affiliation: Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Jensen
authors.affiliation: Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Ling
authors.initials: L
authors.lastname: Feng
authors.affiliation: Department of Clinical Physiology, Nuclear Medicine, and PET, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Ian
authors.initials: I
authors.lastname: Law
authors.affiliation: Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Claus
authors.initials: C
authors.lastname: Svarer
authors.affiliation: Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Gitte M
authors.initials: GM
authors.lastname: Knudsen
authors.affiliation: Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Jens D
authors.initials: JD
authors.lastname: Mikkelsen
authors.affiliation: Department of Clinical Physiology, Nuclear Medicine, and PET, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Robin
authors.initials: R
authors.lastname: de Nijs
authors.affiliation: Department of Radiology, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Vibeke A
authors.initials: VA
authors.lastname: Larsen
authors.affiliation: Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Agnete
authors.initials: A
authors.lastname: Dyssegaard
authors.affiliation: Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Gerda
authors.initials: G
authors.lastname: Thomsen
authors.affiliation: Department of Neurosurgery, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Walter
authors.initials: W
authors.lastname: Fischer
authors.affiliation: Université François-Rabelais de Tours, INSERM U930 "Imaging and Brain," Tours, France; and.
authors.forename: Denis
authors.initials: D
authors.lastname: Guilloteau
authors.affiliation: Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark Epilepsy Clinic, Department of Neurology, Rigshospitalet, Copenhagen, Denmark pinborg@nru.dk.
authors.forename: Lars H
authors.initials: LH
authors.lastname: Pinborg
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D001932:Brain Neoplasms / Q000175:diagnosis / Q000378:metabolism*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D005682:Gadolinium; D005909:Glioblastoma / Q000175:diagnosis / Q000378:metabolism*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D057054:Molecular Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D018079:Receptors, GABA / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed / Q000379:methods*; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics
chemical_list: C504993:6-chloro-2-(4'-iodophenyl)-3-(N,N-diethyl)imidazo(1,2-a)pyridine-3-acetamide; D014408:Biomarkers, Tumor; D019086:Bridged Bicyclo Compounds, Heterocyclic; D019275:Radiopharmaceuticals; D018079:Receptors, GABA; C499229:TSPO protein, human; D019788:Fluorodeoxyglucose F18; C545932:(18F)fluoroethyltyrosine; D014443:Tyrosine; D005682:Gadolinium
keywords: MRI; PET; SPECT; neurooncology