EORTC PET response criteria are more influenced by reconstruction inconsistencies than PERCIST but both benefit from the EARL harmonization program

• Published in: EJNMMI physics 2017-05, Vol.4 (1), p.17-17, Article 17
• Main Authors: Lasnon, Charline, Quak, Elske, Le Roux, Pierre-Yves, Robin, Philippe, Hofman, Michael S., Bourhis, David, Callahan, Jason, Binns, David S., Desmonts, Cédric, Salaun, Pierre-Yves, Hicks, Rodney J., Aide, Nicolas
• Format: Article
• Language: English
• Subjects: 18F-FDG; Applied and Technical Physics; Cancer; Classification; Computational Mathematics and Numerical Analysis; Criteria; Engineering; EORTC; Harmonization; Imaging; Life Sciences; Light emitting diodes; Medicine; Medicine & Public Health; Nuclear Medicine; Optimization; Original Research; Patients; PERCIST; PET; Point spread functions; Radiology; Reconstruction; Reduction; Therapy response; Tumors
• ISSN: 2197-7364; 2197-7364
• DOI: 10.1186/s40658-017-0185-4

Background This study evaluates the consistency of PET evaluation response criteria in solid tumours (PERCIST) and European Organisation for Research and Treatment of Cancer (EORTC) classification across different reconstruction algorithms and whether aligning standardized uptake values (SUVs) to the European Association of Nuclear Medicine acquisition (EANM)/EARL standards provides more consistent response classification. Materials and methods Baseline ( PET1 ) and response assessment ( PET2 ) scans in 61 patients with non-small cell lung cancer were acquired in protocols compliant with the 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 using standardized uptake values corrected for lean body mass (SUL). Results Using OSEM PET1 /OSEM PET2 (standard scenario), responders displayed a reduction of −57.5% ± 23.4 and −63.9% ± 22.4 for SUL max and SUL peak , respectively, while progressing tumours had an increase of +63.4% ± 26.5 and +60.7% ± 19.6 for SUL max and SUL peak respectively. The use of PSF ± TOF reconstruction impacted the classification of tumour response. For example, taking the OSEM PET1 /PSF ± TOF PET2 scenario reduced the apparent reduction in SUL in responding tumours (−39.7% ± 31.3 and −55.5% ± 26.3 for SUL max and SUL peak , respectively) but increased the apparent increase in SUL in progressing tumours (+130.0% ± 50.7 and +91.1% ± 39.6 for SUL max and SUL peak , respectively). Consequently, variation in reconstruction methodology (PSF ± TOF PET1 /OSEM PET2 or OSEM PET1 /PSF ± TOF PET2 ) led, respectively, to 11/61 (18.0%) and 10/61 (16.4%) PERCIST classification discordances and to 17/61 (28.9%) and 19/61 (31.1%) EORTC classification discordances. An agreement was better for these scenarios with application of the propriety filter, with kappa values of 1.00 and 0.95 compared to 0.75 and 0.77 for PERCIST and kappa values of 0.93 and 0.95 compared to 0.61 and 0.55 for EORTC, respectively. Conclusion PERCIST classification is less sensit