Towards building advanced machine learning image translation models to estimate Amyloid-Beta and Tau PET images from structural MRI

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Image-translation is an advanced form of machine learning. It can be used to generate high-cost images from lower-cost inputs. Alzheimer's Disease is the most common type of dementia, impacting tens of millions of people worldwide. A popular hypothesis proposes Amyloid-Beta and Tau are the main causes of Alzheimer's Disease, aggregating in the brain forming the well-known 'plaques.' These plaques have been visible on microscopes from the brains of post-mortem demented patients for over a hundred years, and more recently can be visualized with PET imaging in-vivo. PET imaging is, however, a very expensive test to run ($3000-to-$8000), relative to a conventional structural MRI ($500). It is also more invasive requiring injection of a radiation inducing tracer and blood sampling during the procedure. Furthermore, the tracers and technologies are not available in all jurisdictions (Very limited use in Alberta!). MRI has the advantage of being more affordable and accessible, it is less invasive, however it does not provide the same detailed molecular information as PET data. Previous studies indicate there is mutual information relating Amyloid-Beta and Tau PET and structural MRI. This project will utilize machine learning to translate structural MRI images to Amyloid-Beta and Tau PET images. Key preliminary work has already been completed, including gathering of the required data, obtaining institutional ethics approval, and building a 2D proof-of-concept model. Aim 1: Develop a Simple 3D U-Net Model that is Capable of PET Estimation; Aim 2: Improve Model Performance with Cost Functions and 3D GAN; Aim 3: Implement Vision Transformer GAN and compare with CNN-GAN. The impact of obtaining Amyloid-Beta and Tau PET images from basic MRI is important for the early detection of Alzheimer's disease. This would facilitate a method for screening, as repeat MRI is very practical and safe, while repeat PET is associated with radiation exposure and the injection of radiation inducing tracer. A notable valuable proposition once refined and validated. Advances in quantitative image translation could be applied to many other high value applications.