title: 11C-MET PET/CT and advanced MRI in the evaluation of tumor recurrence in high-grade gliomas.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the performance of l-[methyl-()11C]methionine (11C-MET) PET/CT and MRI (with the inclusion of advanced imaging techniques, namely, MR spectroscopy and MR perfusion) in the assessment of tumor recurrence in high-grade gliomas.
  
  
  METHODS
  Twenty-nine patients with high-grade gliomas who underwent surgical resection, external beam radiation therapy, and standard regimens of chemotherapy were subjected to MRI (conventional, MR perfusion, and MR spectroscopy) and 11C-MET PET/CT scans. A definitive diagnosis was made based on histopathology and/or long-term clinical and radiological follow-up. Several indices were obtained for lesion characterization, namely, SUVmean, SUVmax, and mean lesion-to-normal tissue on PET/CT, as well as relative cerebral blood volume and choline-to-creatine ratio on MRI.
  
  
  RESULTS
  Histological examination revealed viable tumor cells in 19 cases, whereas the remaining 10 were deemed to be negative based on histology (3 cases) or long-term follow-up (7 cases). All the quantitative indices mentioned previously tended to be higher in patients with tumor recurrence/residual. The sensitivity, specificity, and accuracy of 11C-MET PET/CT in identifying tumor recurrence/residual were 94.7%, 80%, and 89.6%, respectively, whereas that of MRI were 84.2%, 90%, and 86.2%, respectively.
  
  
  CONCLUSIONS
  Both 11C-MET PET/CT and MRI (with the inclusion of advanced MRI techniques) demonstrated a high diagnostic performance in the identification of tumor residual/recurrence in high-grade gliomas posttherapy. Although 11C-MET PET/CT seemed to be more sensitive, whereas advanced MRI seemed more specific, there was no statistically significant difference in the diagnostic performance of either modality in the present study. Further studies with a larger group of patients are warranted.
authors.affiliation: From the Institute of Nuclear Medicine Allied Sciences, Brig SK Majumdar Marg, Delhi, India.
authors.forename: Maria M
authors.initials: MM
authors.lastname: D'Souza
authors.forename: Rajnish
authors.initials: R
authors.lastname: Sharma
authors.forename: Abhinav
authors.initials: A
authors.lastname: Jaimini
authors.forename: Puja
authors.initials: P
authors.lastname: Panwar
authors.forename: Sanjiv
authors.initials: S
authors.lastname: Saw
authors.forename: Prabhjot
authors.initials: P
authors.lastname: Kaur
authors.forename: Anupam
authors.initials: A
authors.lastname: Mondal
authors.forename: Anil
authors.initials: A
authors.lastname: Mishra
authors.forename: Rajendra P
authors.initials: RP
authors.lastname: Tripathi
mesh_terms: D000293:Adolescent; D000328:Adult; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D002250:Carbon Radioisotopes; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008715:Methionine / Q000031:analogs & derivatives; D008875:Middle Aged; D064847:Multimodal Imaging; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000473:pathology; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed
chemical_list: D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D008715:Methionine; C038344:methionine methyl ester