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In glioma patients, differentiation between tumor progression (TP) and treatment-related changes (TRCs) remains challenging. Difficulties in classifying imaging alterations may result in a delay or an unnecessary discontinuation of treatment. PET using O-(2-18 F-fluoroethyl)-L-tyrosine ( 18 F-FET) has been shown to be a useful tool for detecting TP and TRCs. Methods: We retrospectively evaluated 127 consecutive patients with World Health Organization grade II-IV glioma who underwent 18 F-FET PET imaging to distinguish between TP and TRCs. 18 F-FET PET findings were verified by neuropathology (40 patients) or clinicoradiologic follow-up (87 patients). Maximum tumor-to-brain ratios (TBR max ) of 18 F-FET uptake and the slope of the time-activity curves (20-50 min after injection) were determined. The diagnostic accuracy of 18 F-FET PET parameters was evaluated by receiver-operating-characteristic analysis and χ 2 testing. The prognostic value of 18 F-FET PET was estimated using the Kaplan-Meier method. Results: TP was diagnosed in 94 patients (74%) and TRCs in 33 (26%). For differentiating TP from TRCs, receiver-operating-characteristic analysis yielded an optimal 18 F-FET TBR max cutoff of 1.95 (sensitivity, 70%; specificity, 71%; accuracy, 70%; area under the curve, 0.75 ± 0.05). The highest accuracy was achieved by a combination of TBR max and slope (sensitivity, 86%; specificity, 67%; accuracy, 81%). However, accuracy was poorer when tumors harbored isocitrate dehydrogenase (IDH) mutations (91% in IDH-wild-type tumors, 67% in IDH-mutant tumors, P , 0.001). 18 F-FET PET results correlated with overall survival (P , 0.001). Conclusion: In our neurooncology department, the diagnostic performance of 18 F-FET PET was convincing but slightly inferior to that of previous reports.

BACKGROUND: Spinal hemangiopericytoma are very rare tumors. There are few case reports and occasional case series on them. We have treated nine patients with spinal hemangiopericytoma in last 11 years. We present a retrospective review of our patients with a focus on clinical presentation, radiological features, management, pathology and outcome. MATERIALS AND METHODS: Between 2004 and 2016, nine patients were treated for spinal hemangiopericytoma. Histopathological data were reviewed in all cases and clinical and follow-up details were collected from data available in our department. RESULTS: There were 5 males and 4 females, including 2 pediatric patients. Mean age of the patients was 31.1 years. Five patients had dorsal spine involvement and 3 patients had involvement of cervical spine. There was one patient with lumbar spine involvement. Most common location of the tumor was intradural extramedullary. All of them presented with motor weakness. Gross total resection of the tumor was done in 6 patients. Eight patients received postoperative radiotherapy. Histopathology showed anaplastic tumor in 6 cases with high MIB-1 LI. Most of them were positive for CD34, mic-2 and bcl-2. All six patients who underwent gross total resection improved significantly and were self ambulatory in the follow-up period. Two patients who underwent subtotal resection expired due to spread of their disease. CONCLUSION: Spinal hemangiopericytoma is a very rare tumor. We present a series of cases treated at out institute for the same. Gross total resection is the goal and radiotherapy should be given in case of residual tumor or high grade tumors. Prognosis is good after gross total excision and functional recovery can be expected in most patients.

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Purpose Integrated histomolecular diagnostics of gliomas according to the World Health Organization (WHO) classification of 2016 has refined diagnostic accuracy and prediction of prognosis. This study aimed at exploring the prognostic value of dynamic O-(2-[ 18 F]fluoroethyl)-L-tyrosine (FET) PET in newly diagnosed, histomolecularly classified astrocytic gliomas of WHO grades III or IV. Methods Before initiation of treatment, dynamic FET PET imaging was performed in patients with newly diagnosed glioblastoma (GBM) and anaplastic astrocytoma (AA). Static FET PET parameters such as maximum and mean tumour/brain ratios (TBR max/mean ), the metabolic tumour volume (MTV) as well as the dynamic FET PET parameters time-to-peak (TTP) and slope, were obtained. The predictive ability of FET PET parameters was evaluated concerning the progression-free and overall survival (PFS, OS). Using ROC analyses, threshold values for FET PET parameters were obtained. Subsequently, univariate Kaplan-Meier and multivariate Cox regression survival analyses were performed to assess the predictive power of these parameters for survival. Results Sixty patients (45 GBM and 15 AA patients) of two university centres were retrospectively identified. Patients with isocitrate dehydrogenase (IDH)-mutant or O 6 -methylguanine-DNA-methyltransferase (MGMT) promoter-methylated tumours had a significantly longer PFS and OS (both P < 0.001). Furthermore, ROC analysis of IDH-wildtype glioma patients (n = 45) revealed that a TTP > 25 min (AUC, 0.90; sensitivity, 90%; specificity, 87%; P < 0.001) was highly prognostic for longer PFS (13 vs. 7 months; P = 0.005) and OS (29 vs. 12 months; P < 0.001). In contrast, at a lower level of significance, TBR max , TBR mean , and MTV were only prognostic for longer OS (P = 0.004, P = 0.038, and P = 0.048, respectively). Besides complete resection and a methylated MGMT promoter, TTP remained significant in multivariate survival analysis (all P ≤ 0.02), indicating an independent predictor for OS. Conclusions Our data suggest that dynamic FET PET allows the identification of patients with longer OS among patients with newly diagnosed IDH-wildtype GBM and AA.