title: Diagnostic Accuracy of PET, SPECT, and Arterial Spin-Labeling in Differentiating Tumor Recurrence from Necrosis in Cerebral Metastasis after Stereotactic Radiosurgery.
abstract: OBJECTIVE
  Radiographic assessment of cerebral metastasis after stereotactic radiosurgery remains a major challenge in neuro-oncology. It is often difficult to distinguish tumor progression from radiation necrosis in this setting using conventional MR imaging. The objective of this study was to compare the diagnostic sensitivity and specificity of different functional imaging modalities for detecting tumor recurrence after stereotactic radiosurgery.
  
  
  METHODS
  We retrospectively reviewed patients treated between 2007 and 2010 and identified 14 patients with cerebral metastasis who had clinical or radiographic progression following stereotactic radiosurgery and were imaged with arterial spin-labeling, FDG-PET, and thallium SPECT before stereotactic biopsy. Diagnostic accuracy, specificity, sensitivity, positive predictive value, and negative predictive value were calculated for each imaging technique by using the pathologic diagnosis as the criterion standard.
  
  
  RESULTS
  Six patients (42%) had tumor progression, while 8 (58%) developed radiation necrosis. FDG-PET and arterial spin-labeling were equally sensitive in detecting tumor progression (83%). However, the specificity of arterial spin-labeling was superior to that of the other modalities (100%, 75%, and 50%, respectively). A combination of modalities did not augment the sensitivity, specificity, positive predictive value, or negative predictive value of arterial spin-labeling.
  
  
  CONCLUSIONS
  In our series, arterial spin-labeling positivity was closely associated with the pathologic diagnosis of tumor progression after stereotactic radiosurgery. Validation of this finding in a large series is warranted.
authors.affiliation: From the School of Medicine (G.L., B.S.C., C.C.C.), University of California, San Diego, La Jolla, California.
authors.forename: G
authors.initials: G
authors.lastname: Lai
authors.affiliation: Departments of Radiation Oncology (A.M.).
authors.forename: A
authors.initials: A
authors.lastname: Mahadevan
authors.affiliation: Radiology (D.H.).
authors.forename: D
authors.initials: D
authors.lastname: Hackney
authors.affiliation: Division of Neurosurgery (P.C.W.), University of Chicago, Chicago, Illinois.
authors.forename: P C
authors.initials: PC
authors.lastname: Warnke
authors.affiliation: Division of Neurosurgery (F.N., E.K.).
authors.forename: F
authors.initials: F
authors.lastname: Nigim
authors.affiliation: Division of Neurosurgery (F.N., E.K.).
authors.forename: E
authors.initials: E
authors.lastname: Kasper
authors.affiliation: Department of Neurology (E.T.W.), Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: E T
authors.initials: ET
authors.lastname: Wong
authors.affiliation: From the School of Medicine (G.L., B.S.C., C.C.C.), University of California, San Diego, La Jolla, California.
authors.forename: B S
authors.initials: BS
authors.lastname: Carter
authors.affiliation: From the School of Medicine (G.L., B.S.C., C.C.C.), University of California, San Diego, La Jolla, California clarkchen@ucsd.edu.
authors.forename: C C
authors.initials: CC
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000556:secondary; D003937:Diagnosis, Differential; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009336:Necrosis / Q000000981:diagnostic imaging; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography; D011832:Radiation Injuries / Q000000981:diagnostic imaging*; D016634:Radiosurgery / Q000009:adverse effects*; D012189:Retrospective Studies; D013113:Spin Labels; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D013113:Spin Labels