RT Journal Article
SR Electronic
T1 EORTC PET response criteria are more affected than PERCIST by reconstruction inconsistencies but both equally benefit from the EARL harmonization program
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 722
OP 722
VO 58
IS supplement 1
A1 Charline Lasnon
A1 Elke Quak
A1 Pierre-Yves Le Roux
A1 Philippe Robin
A1 Michael Hofman
A1 David Bourhis
A1 Jason Callahan
A1 David Binns
A1 Cédric Desmonts
A1 Pierre-Yves Salaun
A1 Rodney Hicks
A1 Nicolas Aide
YR 2017
UL http://jnm.snmjournals.org/content/58/supplement_1/722.abstract
AB 722Objectives: In the framework of therapeutic response assessment using PET, pre- and post-treatment scans should ideally involve identical acquisition and processing. However, this is often impractical in busy PET centres, especially those running several scanners, and this can also be challenged by scanner upgrade during a trial or patient’s mobility. This study evaluates the consistency of PERCIST and EORTC classification across different reconstruction algorithms and whether aligning standardized uptake values (SUVs) to the European Association of Nuclear Medicine acquisition (EANM)/EARL standards provide consistent response classification.Methods: Response assessment PET scans in 61 patients with non-small cell lung cancer were acquired in protocols compliant with EANM guidelines and were reconstructed with point spread function (PSF) or PSF + time-of-flight (TOF) reconstruction for optimal tumour detection and with a standardized ordered subset expectation maximization (OSEM) reconstruction known to fulfil EANM harmonizing standards. Patients were recruited in three centres. Following reconstruction, EQ.PET, a proprietary software solution was applied to the PSF±TOF data (PSF±TOF.EQ) to harmonize SUVs to the EANM standards. The impact of differing reconstructions on PERCIST and EORTC classification was evaluated.Results: Using OSEM1/ OSEM2 (standard scenario), responders displayed a reduction of -59.2%±23.5 and -63.9%±22.4 for SULmax and SULpeak respectively, while progressing tumours had an increase of +63.4%±26.5 and +60.7%±19.6 for SULmax and SULpeak respectively. The use of PSF±TOF reconstruction impacted classification of tumour response. For example, taking the OSEM1/PSF±TOF2 scenario reduced the apparent reduction in SUL in responding tumours (-42.3%±31.2 and -55.5%±26.3 for SULmax and SULpeak, respectively) but increased the apparent increase in SUL in progressing tumours (+130.0%±50.7 and +91.1%±39.6 for SULmax and SULpeak, respectively). Consequently, variation in reconstruction methodology (PSF±TOF1/OSEM2 or OSEM1/PSF±TOF2) led to 11/61 (18.0%) and 10/61 (16.4%) PERCIST classification discordances, respectively, and to 18/61 (29.5%) and 19/61 (31.1%) EORTC classification discordances, respectively. Agreement was better for these scenarios with application of the propriety filter, with kappa values of 0.93 and 0.95 compared to 0.75 and 0.77 for PERCIST and kappa values of 0.95 and 0.95 compared to 0.59 and 0.55 for EORTC, respectively.Conclusion: PERCIST classification is less sensitive to reconstruction algorithm-dependent variability than EORTC classification but harmonizing SULs within the EARL program is equally effective with either. Research Support: Siemens R&D, Oxford