title: The value of11C-methionine PET in the early differentiation between tumour recurrence and radionecrosis in patients treated for a high-grade glioma and indeterminate MRI.
abstract: OBJECTIVE
  To evaluate the contribution of11C-Methionine PET in the early differentiation between tumour recurrence and radionecrosis in patients treated for a high grade glioma.
  
  
  METHODS
  The study included 30 patients with glioma (III/IV grade) treated with surgery/radiotherapy/chemotherapy (5-8 months) and with an indeterminate MRI. All patients underwent a11C-Methione PET (within 15 days of MRI) and studies were visually analysed (intensity and morphology of uptake), quantified (SUV max/SUV mean background), and coregistered to MRI (3D-Flair). Patient management was decided by the neuro-oncology committee to clinical and imaging follow-up, second-line treatment, or surgery.
  
  
  RESULTS
  There were 2311C-Methionine PET studies visually positive. Morphology of uptake was focal in 15, diffuse in 4, and ring-shaped in 4. Three out of the focal uptake cases underwent resection (Histopathology +). Sixteen underwent second-line therapy (11 responded; 5 progressed). The 4 cases with ring-shaped uptake were followed-up, and progression was found in 2 (true-positive), and disease-free in 2 (follow-up of 6 and 7 months, respectively) (false-positive). Seven out of11C-Methionine studies PET were visually negative, and all of them were disease-free (follow-up of 3-12 months). SUV lesion/background was 2.79±1.35 in tumour recurrence, and 1.53±0.39 in radionecrosis (P<.05). Taking into account a SUV lesion/background threshold of 2.35, the sensitivity and specificity values were 90.5% and 100%, respectively.
  
  
  CONCLUSIONS
  Visual analysis, quantitative and PET/MRI coregistration of11C-Methionine PET showed their complementary role in patients with indeterminate MRI results, thus allowing early differentiation between tumour recurrence and radionecrosis, and helping in the individual therapy approach.
authors: CETIR Unidad PET, CETIR-ERESA, Esplugues, Barcelona, España. Electronic address: jrgarcia@cetir.es.
authors: J R
authors: JR
authors: Garcia
authors: CETIR Unidad PET, CETIR-ERESA, Esplugues, Barcelona, España.
authors: M
authors: M
authors: Cozar
authors: CETIR Unidad PET, CETIR-ERESA, Esplugues, Barcelona, España.
authors: M
authors: M
authors: Baquero
authors: CETIR Unidad PET, CETIR-ERESA, Esplugues, Barcelona, España.
authors: J M
authors: JM
authors: Fernández Barrionuevo
authors: CETIR Unidad PET, CETIR-ERESA, Esplugues, Barcelona, España.
authors: A
authors: A
authors: Jaramillo
authors: CETIR Unidad PET, CETIR-ERESA, Esplugues, Barcelona, España.
authors: J
authors: J
authors: Rubio
authors: CETIR Unidad PET, CETIR-ERESA, Esplugues, Barcelona, España.
authors: G
authors: G
authors: Maida
authors: CETIR Unidad PET, CETIR-ERESA, Esplugues, Barcelona, España.
authors: M
authors: M
authors: Soler
authors: CETIR Unidad PET, CETIR-ERESA, Esplugues, Barcelona, España.
authors: E
authors: E
authors: Riera
mesh_terms: D000328:Adult; D000368:Aged; D020208:Brain Injury, Chronic / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D002250:Carbon Radioisotopes / Q000032:analysis*; D003131:Combined Modality Therapy; D042241:Early Diagnosis; D005189:False Positive Reactions; D005260:Female; D005500:Follow-Up Studies; D005909:Glioblastoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008715:Methionine / Q000032:analysis*; D008875:Middle Aged; D009336:Necrosis; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D059906:Neuroimaging / Q000379:methods*; D049268:Positron-Emission Tomography; D011832:Radiation Injuries / Q000000981:diagnostic imaging* / Q000473:pathology; D019275:Radiopharmaceuticals / Q000032:analysis*; D011878:Radiotherapy / Q000009:adverse effects; D012680:Sensitivity and Specificity
chemical_list: D002250:Carbon Radioisotopes; C000615233:Carbon-11; D019275:Radiopharmaceuticals; D008715:Methionine
keywords: (11)C-Methionine PET; Glioma; MRI; PET con (11)C-metionina; RM; Radionecrosis; Recurrencia tumoral; Tumour recurrence