Applicability of Advanced Diffusion Magnetic Resonance Imaging in clinical routine of Neonatal Data

Diffusion Magnetic Resonance Imaging (dMRI), a variant of conventional MRI based on the tissue water diffusion rate, has recently gathered an extraordinary interest among the scientific community due to the relationships found between several neurological and neurosurgical pathologies and alterations in diffusivity of both white and gray matter. It can thus be considered the imaging method of choice to study the brain, and several steps forward have been made from Diffusion Tensor Imaging (DTI) - the method which first showed the capabilities of dMRI - to advanced diffusion analysis methods. Applying these cutting-edge imaging techniques to investigate pediatric subjects is gaining increasing popularity precisely for the unparalleled sensitivity to tissue microstructure compared to conventional MRI. Indeed, advanced dMRI models turn out to be ideal for investigating fast tissue growth and differentiation characterizing early infancy and not detectable with the same degree of sensitivity with structural MRI. If, with regard to infant brain, most recent dMRI techniques have already been successfully applied in research studies and are entering clinical routine, their use in imaging of neonatal spinal cord is still unexplored. Nonetheless, we are dealing with an innovative, up-to-date domain which holds great promise for diagnosis and understanding of pathological conditions due to injury of both grey and white matter tracts. However, there are considerable challenges to this kind of imaging and research at present is focusing its effort on sorting them out. Further issues concern the application of this imaging in a pediatric clinical setting, which presents specific requirements in terms of acquisition sequences in contrastto current advanced diffusion methods. The main goal of my PhD project, in collaboration with the LIFT (Laboratorio di Imaging Funzionale a 3Tesla) of Gaslini Children’s Hospital in Genoa, has been to allow translation of advanced dMRI methods into clinical routine for the analysis of neonatal data, both in brain and spinal cord, considering the close interconnection between these two districts. Specifically, during my PhD work, I have paid particular attention to: (i) the design of ad-hoc acquisition sequences and preprocessing pipelines tailored for neonates - a crucial step at this delicate age-range; (ii) the application of Diffusion Kurtosis Imaging (DKI) model, a promising extension of DTI quantifying non-gaussian diffusion in biological tissues; and (iii) the investigation of preterm birth in order to find new potential biomarkers, given its still high incidence and adverse impact worldwide.