Abstract / Summary
Abstract Purpose. To compare the metabolic imaging characteristics and prognostic value of 11 C-methionine and 18 F-fluorodeoxyglucose PET/CT in NF2-related vestibular schwannomas. Methods. This single-center retrospective cohort included 22 adults with 40 untreated vestibular schwannomas who underwent baseline 11 C-MET and 18 F-FDG PET/CT and audiological assessment. Median follow-up was 21 months. Tracer uptake and tumor-to-cerebellum ratios were compared. Receiver operating characteristic and Cox regression analyses evaluated associations with volumetric tumor progression and hearing deterioration. Results. Although maximum standardized uptake value (SUVmax) was higher with 18 F-FDG than with 11 C-MET (3.69 ± 1.12 vs 3.08 ± 0.83; P < .001), maximum tumor-to-background ratio (TBRmax) was substantially higher with 11 C-MET (2.43 ± 0.59 vs 0.54 ± 0.14; P < .0001). For predicting tumor progression, 11 C-MET TBRmax achieved an area under the curve of 0.753, compared with 0.507 for 18 F-FDG TBRmax (P = .02). Corresponding values for hearing deterioration were 0.736 and 0.531. In multivariable analysis, 11 C-MET TBRmax independently predicted tumor progression (hazard ratio, 2.958; 95% confidence interval, 1.380–6.339; P = .0053) and hearing deterioration (hazard ratio, 3.223; 95% confidence interval, 1.021–10.172; P = .046). No 18 F-FDG-derived parameter was significantly associated with either outcome. Conclusion. 11 C-MET PET/CT provided superior tumor-to-background contrast and stronger prognostic information than 18 F-FDG PET/CT in NF2-related vestibular schwannomas. These findings support prospective evaluation of 11 C-MET TBRmax as an imaging biomarker for individualized surveillance.