New method produces faster and higher quality human imaging

MR-PET scannerThe latest imaging technology that combines magnetic resonance imaging with positron emission tomography (MR-PET) has allowed researchers to simultaneously investigate the structural, functional and metabolic aspects of the body.

While this technology has created unprecedented imaging capabilities for clinicians and researchers, considerable time is required to independently reconstruct the MR and PET data generated by the scanner.

Researchers from Monash Biomedical Imaging (MBI) have now developed a way to combine the MR and PET data through a joint image reconstruction system that also improves the quality and speed of images generated by simultaneous MR-PET scanners.

The Imaging Analysis Team’s ‘joint MR-PET dictionary’ improves on current image reconstruction methods by leveraging MR anatomical information to improve the quantitative accuracy of PET imaging while reducing image noise and artifacts.

The Bayesian dictionary approach enables accurate reconstruction of PET and MRI images with improved PET spatial resolution and signal to noise ratio, even under increased under sampling of MRI data.

The researchers are currently also developing ‘deep learning’ methods, in which a computer recognises and removes any artifacts in the data to give a much cleaner image for the clinician or researcher to work with. The joint MR-PET reconstruction method is currently being applied to low dose PET imaging with a reduction of FDG radiotracer up to 50 times.

The PhD student researcher on the project, Viswanath Pamulakanty Sudarshan, said the dictionary is a vast improvement on current reconstruction methods as it learns higher-level dependencies such as textures rather than relying on lower-level features such as image gradients.

“Our method also minimises the transfer of MR and PET artifacts across each modality and ensures robustness in managing subject differences in radiotracer dosages, which are required for the PET imaging component,” he said.

This work has been published in Medical Image Analysis.

MBI operates Australia’s only research dedicated MR-PET scanner, which is currently used in a range of clinical studies, including those investigating healthy ageing and neurodegenerative disorders.