TY - JOUR T1 - Diagnostic Accuracy of PET, SPECT, and Arterial Spin-Labeling in Differentiating Tumor Recurrence from Necrosis in Cerebral Metastasis after Stereotactic Radiosurgery JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 2250 LP - 2255 DO - 10.3174/ajnr.A4475 VL - 36 IS - 12 AU - G. Lai AU - A. Mahadevan AU - D. Hackney AU - P.C. Warnke AU - F. Nigim AU - E. Kasper AU - E.T. Wong AU - B.S. Carter AU - C.C. Chen Y1 - 2015/12/01 UR - http://www.ajnr.org/content/36/12/2250.abstract N2 - BACKGROUND AND PURPOSE: 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.MATERIALS AND 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.ASLarterial spin-labelingCEcontrast-enhancedNPVnegative predictive valuePPVpositive predictive valueRNradiation necrosisSRSstereotactic radiosurgerySUVstandard uptake valueTPtumor progression ER -