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Pre- and posttreatment PET comparative scans should ideally be obtained with identical acquisition and processing, but this is often impractical. The degree to which differing protocols affect PERCIST classification is unclear. This study evaluates the consistency of PERCIST classification across different reconstruction algorithms and whether a proprietary software tool can harmonize SUV estimation sufficiently to provide consistent response classification., Methods: Eighty-six patients with non-small cell lung cancer, colorectal liver metastases, or metastatic melanoma who were scanned for therapy monitoring purposes were prospectively recruited in this multicenter trial. Pre- and posttreatment PET scans were acquired in protocols compliant with the Society of Nuclear Medicine and Molecular Imaging and the European Association of Nuclear Medicine (EANM) acquisition guidelines and were reconstructed with a point spread function (PSF) or PSF + time-of-flight (TOF) for optimal tumor detection and also with standardized ordered-subset expectation maximization (OSEM) known to fulfill EANM harmonizing standards. After reconstruction, a proprietary software solution was applied to the PSF ± TOF data (PSF ± TOF.EQ) to harmonize SUVs with the OSEM values. The impact of differing reconstructions on PERCIST classification was evaluated., Results: For the OSEM PET1 /OSEM PET2 (OSEM reconstruction for pre- and posttherapeutic PET, respectively) scenario, which was taken as the reference standard, the change in SUL was -41% ± 25 and +56% ± 62 in the groups of tumors showing a decrease and an increase in 18 F-FDG uptake, respectively. The use of PSF reconstruction affected classification of tumor response. For example, taking the PSF ± TOF PET1 /OSEM PET2 scenario increased the apparent reduction in SUL in responding tumors (-48% ± 22) but reduced the apparent increase in SUL in progressing tumors (+37% ± 43), as compared with the OSEM PET1 /OSEM PET2 scenario. As a result, variation in reconstruction methodology (PSF ± TOF PET1 /OSEM PET2 or OSEM PET1 /PSF ± TOF PET2 ) led to 13 of 86 (15%) and 17 of 86 (20%) PERCIST classification discordances, respectively. Agreement was better for these scenarios with application of the propriety filter, with κ values of 1 and 0.95 compared with 0.79 and 0.72, respectively., Conclusion: Reconstruction algorithm-dependent variability in PERCIST classification is a significant issue but can be overcome by harmonizing SULs using a proprietary software tool., (© 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.)

Unlabelled: We investigated the incremental management impact and prognostic value of staging with (18)F-FDG PET/CT in patients with non-small cell lung cancer (NSCLC) being considered for potentially curative therapies., Methods: Information on 168 consecutive patients with NSCLC being considered for surgery or definitive radiotherapy with curative intent before PET/CT was entered into a prospective database. The pre-PET/CT management plan, based on conventional imaging (conventional CT, appropriately supplemented by bone scintigraphy or other modalities), was defined prospectively by referring clinicians before PET/CT results became available. After PET/CT, actual clinical management was recorded, and patients were followed up until 5 y or death. The appropriateness of PET/CT management plans was assessed by biopsy when available, clinical follow-up, and survival analysis., Results: Stage was discordant on PET/CT and conventional imaging in 50.6% of patients (41.1% upstaged, 9.5% downstaged), with high management impact (change in treatment modality or curative intent) in 42.3% of patients. Both conventional imaging stage and PET/CT stage were strongly predictive of overall survival (OS) but there were greater differences between hazard rates and separations in the OS curves for stage groupings determined using PET/CT. OS was also strongly predicted by PET/CT-directed choice of therapy (P < 0.0001)., Conclusion: PET/CT frequently affects patient management and strongly predicts OS in NSCLC, supporting the appropriateness of such changes.

Unlabelled: This study applied decision tree analysis to evaluate the sensitivity, specificity, and cost-effectiveness of clinical algorithms that incorporate 18F-FDG PET., Methods: A cohort of 176 patients was studied. The localization rate, accuracy, therapeutic impact on the presurgical decision-making process, and correlation with the postsurgical outcome were assessed for the tests commonly performed for seizure localization. Decision tree sensitivity analysis compared 3 imaging strategies with a baseline strategy of medical therapy for all: video-electroencephalography monitoring (VEM)/MRI strategy, in which patients underwent VEM and brain MRI only, and +SPECT and +PET strategies, in which patients with an indeterminate VEM/MRI result underwent ictal SPECT or interictal 18F-FDG PET, respectively., Results: The localization rates for VEM, MRI, 18F-FDG PET, ictal SPECT, and intracranial electroencephalography (EEG) were 62.2%, 35.8%, 75.0%, 60.0%, and 93.8%. The VEM/MRI strategy had the lowest cost per class I/II outcome, but the additional costs per class I/II outcome for the +PET and +SPECT strategies were always below the minimum reported cost savings for a class I/II outcome. There were no valid conditions in which the +SPECT strategy had a lower cost per class I/II outcome than the +PET strategy. Within the range of cost savings estimated to be associated with a class I/II outcome, all decision strategies produced net cost savings; however, these were significantly higher for the +PET and the +SPECT strategies., Conclusion: 18F-FDG PET is cost-effective in the presurgical evaluation, particularly when used in patients with a nonlocalizing or nonconcordant VEM or MRI result.