title: (201)Tl-SPECT in low-grade gliomas: diagnostic accuracy in differential diagnosis between tumour recurrence and radionecrosis.
abstract: OBJECTIVE
  The aim of this work was to describe the usefulness of a simple (201)Tl single-photon emission computed tomography (SPECT) technique in the differential diagnosis between tumour recurrence and radionecrosis during the follow-up of patients treated for low-grade gliomas.
  
  
  METHODS
  The study population comprised 84 patients treated for low-grade gliomas who showed suspicion of tumour recurrence during their follow-up. All patients were examined by neuro-anatomical imaging procedures (CT, MRI) and (201)Tl-SPECT. (201)Tl-SPECT images were assessed by visual analysis based only on the information on the prescription form and by estimation of the uptake index (ratio of mean counts in the lesion to those in the contralateral mirror area). Examiners were blinded to the results of other tests.
  
  
  RESULTS
  Under these conditions, the neuro-anatomical procedures yielded 26.2% inconclusive reports, with a global diagnostic accuracy of 0.61, a sensitivity of 0.63 and a specificity of 0.59. The global diagnostic accuracy for (201)Tl-SPECT was 0.83, with a sensitivity of 0.88 and a specificity of 0.76. Diagnostic pitfalls were observed in regions with physiological (201)Tl uptake, i.e. the posterior cranial fossa, diencephalon, lateral ventricles and cavernous and longitudinal venous sinuses. An uptake index cut-off value of 1.25 showed a sensitivity of 0.90 and specificity of 0.80 for detection of tumour activity.
  
  
  CONCLUSIONS
  (201)Tl-SPECT has adequate diagnostic accuracy to be part of routine algorithms in the follow-up of patients with low-grade glioma suspected of tumour recurrence, as an alternative to neuro-anatomical procedures and not solely as a complementary test.
authors.affiliation: Department of Nuclear Medicine, "Virgen de las Nieves" University Hospital, Ada. Fuerzas Armadas 2, 18014, Granada, Spain, manuel.gomez.rio.sspa@juntadeandalucia.es
authors.forename: Manuel
authors.initials: M
authors.lastname: Gómez-Río
authors.forename: Dolores
authors.initials: D
authors.lastname: Martínez Del Valle Torres
authors.forename: Antonio
authors.initials: A
authors.lastname: Rodríguez-Fernández
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Llamas-Elvira
authors.forename: Simeón Ortega
authors.initials: SO
authors.lastname: Lozano
authors.forename: Carlos Ramos
authors.initials: CR
authors.lastname: Font
authors.forename: Escarlata
authors.initials: E
authors.lastname: López Ramírez
authors.forename: Majed
authors.initials: M
authors.lastname: Katati
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology*; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D003937:Diagnosis, Differential; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D006801:Humans; D008297:Male; D009336:Necrosis; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging*; D011379:Prognosis; D011832:Radiation Injuries / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013793:Thallium; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D016896:Treatment Outcome
chemical_list: D019275:Radiopharmaceuticals; C027549:thallium chloride; D013793:Thallium