Alexander Leemans

UMC Utrecht

In short, Alexander Leemans' research entails the following: 

Harmonization and segmentation of multicenter paediatric sarcoma MRI data through artificial intelligence to support clinical decision making in international trials

'Rhabdomyosarcoma and Ewing sarcoma are rare tumours with a prevalence of around 35 cases per year in the Dutch paediatric and adolescent population. Currently, there are no biomarkers that can distinguish between poor and good outcomes at an early stage of treatment of these tumours. While microstructural tissue properties derived from diffusion MRI (dMRI) could be valuable biomarkers for early assessment of treatment efficacy, differences in scanner hardware and acquisition protocols across sites complicate dMRI data pooling necessary for clinical decision making in international trials. In this project, we will develop artificial intelligence (AI) methodology for harmonizing dMRI signals and segmenting tumour MRI data that can alleviate unwanted multicenter variability while preserving the biological signature of tissue microstructure.'

Brief summary of progress / results July 2023

MRI scans of pediatric patients with rhabdomyosarcoma were collected from multiple centers across Europe. In the first months of this project, the images and relative metadata were organized in a database. Given our interest in harmonization of diffusion MRI data, a preliminary study was conducted trying to ascertain whether ADC maps automatically calculated from scanners from different vendors are comparable to ADC maps calculated with a standardized in-house pipeline. Values within the tumors were compared and no significant difference has been found in the subset of images analyzed. While the research to expand our current dataset using already existing scans is still ongoing, an MRI acquisition protocol for the acquisition of a multi-scanner MRI database on volunteers has been developed. Moreover, a framework for manual segmentation of tumor and main healthy structures has been implemented, to be used as ground truth in future steps of the study.