Application and Development of Contrast-Enhanced Ultrasound for Perfusion Quantification in Kidney Disease

Abstract

Changes in microvascular perfusion play a critical role in the pathophysiology of kidney disease and its sequelae. This thesis describes research work that aimed to optimise and use an ultrasound imaging method to quantify tissue perfusion in patients with kidney disease, specifically Contrast Enhanced Ultrasound (CEUS) applied in the kidneys and in skeletal muscle. This work systematically reviewed prior evidence about the acute changes that haemodialysis exerts on skeletal muscle perfusion, metabolism and function. In a clinical study, changes in skeletal muscle microvascular perfusion during haemodialysis are then explored, as a potential factor that could contribute to skeletal muscle wasting in this population. Findings are then corroborated by an analysis of pre-existing data looking at the associations between hand-grip strength, dialysis related parameters (e.g. blood pressure and ultrafiltration volume) and nutritional measures. In the second half of the thesis, CEUS is used to assess renal perfusion, optimising the protocol for CEUS in healthy volunteers. Then, intra-subject repeatability of the different CEUS perfusion parameters was determined in healthy volunteers studied twice, as well as inter-operator repeatability of image analysis. Finally, a pilot study was undertaken in patients with AKI applying CEUS in this setting and generating preliminary clinical data.