Evaluation of functional magnetic resonance imaging biomarkers (perfusion, diffusion and longitudinal relaxation T1) in transplanted kidneysemerging biomarkers with clinical potential

Resumen

Chronic Kidney Disease (CKD) is a major social and global problem, with a large prevalence. Kidney transplantation is the therapy of choice for patients at kidney failure. Monitoring the kidney function after the surgery is key for the early detection of allograft impartment and thus, to guide the therapeutic treatment in order to prevent the allograft loss. Multiparametric renal magnetic resonance imaging (MRI) has appeared as a promising non-invasive technique for the assessment and characterization of both renal physiology and physiopathology as it can quantify renal biomarkers associated with different pathologies. Among these biomarkes are perfusion, diffusion or T1 values. The work in this Thesis was focused on the optimization of perfusion magnetic resonance imaging techniques for its application in both native and transplanted kidneys. In particular, pseudo continuous arterial spin labeling (PCASL) was implemented and optimized to measure renal perfusion. The results of this study revealed the optimal parameters that maximize PCASL efficiency. In addition, a multiparametric MRI (mpMRI) protocol was implemented to characterize perfusion, diffusion and T1 values. This procotol was validated in a group of transplanted kidney patients with stable function. The feasibility and reproducibility of the procotol was assessed, and the normal ranges of mpMRI parameters in this group of patiens were characterized. Finally, this mpMRI protocol was employed to assess kidney function in a longitudinal study in renal allografts since the early stages after transplantation, to assess the diagnostic and prognostic value of multiparamteric MRI protocol.