A novel approach for quantitative harmonization in PET

Abstract

Positron emission tomography (PET) imaging allows for measurement of activity concentrations of a given radiotracer in vivo. The quantitative capabilities of PET imaging are particularly important in the context of monitoring response to treatment, where quantitative changes in tracer uptake could be used as a biomarker of treatment response. Reconstruction algorithms and settings have a significant impact on PET quantification. In this work we introduce a novel harmonization methodology requiring only a simple cylindrical phantom and show that it can match the performance of more complex harmonization approaches based on phantoms with spherical inserts. Resolution and noise measurements from cylindrical phantoms are used to simulate the spherical inserts from NEMA image quality phantoms. An optimization algorithm was used to find the optimal smoothing filters for the simulated NEMA phantom images to identify those that best harmonized the PET scanners. Our methodology was tested on seven different PET models from two manufacturers installed at five institutions. Our methodology is able to predict contrast recovery coefficients (CRCs) from NEMA phantoms with errors within ±5.2% for CRCmax and ±3.7% for CRCmean (limits of agreement = 95%). After applying the proposed harmonization protocol, all the CRC values were within the tolerances from EANM. Quantitative harmonization in compliance with the EARL FDG-PET/CT accreditation program is achieved in a simpler way, without the need of NEMA phantoms. This may lead to simplified scanner harmonization workflows more accessible to smaller institutions.

Importance of incorporating quantitative imaging biomarker technical performance characteristics when estimating treatment effects

“…models and makes) can occur. Harmonization of measurements to a set of common reference values has been proposed as a way to account for differences across scanner makes/models/upgrades (see Makris et al 32 and Namias et al 33 for examples in multicenter fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT studies). However, it is very challenging to correct for system hardware or software changes even using calibration standards imbedded in patient imaging protocols.…”

Striatal D1 and D2 receptor availability are selectively associated with eye-blink rates after methylphenidate treatment

“…In addition, stimulus drugs such as MP influence sympathetic activity increasing noradrenergic signaling, which could influence EBR in currently unknown ways. Lastly, our harmonization method ran on the parametric images, which helps overcome some of the limitations of the methods that run the harmonization on the raw images 42 .…”

Simultaneous PET/MRI: The future gold standard for characterizing motor neuron disease—A clinico-radiological and neuroscientific perspective

“…While PET measurements, in principle, allow for absolute quantitation measures, such as regional cerebral blood volume, regional cerebral glucose metabolism, or regional receptor occupancy, the evaluation of multicentric data makes procedures for harmonization of data acquisition and processing mandatory (13)(14)(15)(16), which is simplified for PET/MRI, where, by design, variability of the underlying technology is limited. Given that technical prerequisites have been met, quantitative measures of different systems relevant to motor neuron disease can be non-invasively acquired and PET/MRI proves useful for individual assessment of the stage of disease (Figure 1).…”