Abstract: Multisite imaging studies increase statistical power and enable the generalization of research outcomes; however, due to the variety of imaging acquisition, different PET tracer properties and inter-scanner variability hinders the direct comparability of multi-scanner PET data. The PET imaging field is lacking behind in terms of harmonization methods due to the complexity associated with combination of different tracers and different scanners. Similarly, MRI present similar challenges, but mainly due to scanner differences. In this study we investigate samples of cognitively normal participants, mild cognitive impaired and Alzheimer’s disease subjects in two major multisite studies of Alzheimer’s disease. We present challenges and solutions associated with different MRI scanners, PET tracers, as well as analysis and harmonization techniques including simple imaging standardization, Combat and deep learning methods. We show regions of interest differences in PET outcome measures before and after the harmonization in multisite studies of Alzheimer’s Disease as well as voxel level harmonization along with summary measures before and after harmonization in MRI studies.

Abstract: Modern medical imaging often faces a “language barrier”, where each modality speaks its own “language” and each site and scanner adds its own “accent”. This variation creates significant challenges for medical professionals and translational AI algorithms. In this talk, I will show how harmonization can serve as a universal translator for medical data, enabling consistent and comparable analysis across diverse clinical and research environments. We will begin by highlighting key challenges and considerations—including site/scanner variability, image quality discrepancies, missing data, and multi-modality. I will then present our strategies and commitment to addressing these issues, emphasizing how more consistent imaging data can enhance both patient care and research outcomes. By the end of the session, participants will gain new insights into how modern technologies can be integrated within various imaging modalities—such as structural MRI, diffusion MRI, and computed tomography—to overcome the unique obstacles posed by multi-site medical imaging.