MRI in Renal Transplantation

Overview

Renal transplantation is the optimal method of treatment for end stage kidney disease however median lifespan of a kidney transplant is around 15 years. Existing methods of measuring transplant function and structure from blood and urine markers are imperfect; renal biopsy is often performed but is invasive. Novel methods of investigating transplant function are therefore required and emerging renal MRI sequences including ASL and diffusion weighted imaging may yield helpful biomarkers. Investigators will recruit 20 patients in the first year after transplant and measure MRI biomarkers at three time points, with correlation to existing methods of measuring transplant function.

Kidney transplantation remains the optimal therapy for patients with end stage kidney disease and is associated with significant improvements in life expectancy and quality of life compared to subjects receiving dialysis. Despite significant advances in our understanding of the immune system and development of drugs to prolong transplant function, a large number (Scottish Renal Registry data suggest between 23-35%) of transplants fail in the 10 years from operation. This may be due to a number of factors but is often due to development of transplant rejection, where the recipient's immune system damages the transplant. Early recognition and implementation of therapy is needed to dampen this response, reduce irreversible damage and preserve transplant function. At present, transplant function and damage is measured using blood and urine tests. These are far from perfect markers because there is a delay between transplant damage and abnormalities of these tests. This time is vital for the short and long term survival of the transplant. In the University of Glasgow, investigators have developed a new type of magnetic resonance imaging (MRI) which allows assessment of kidney blood flow and fibrosis (scarring) without the need for administration of harmful contrast agents. Arterial spin labelling magnetic resonance imaging (ASL MRI) is a non-invasive method of measuring renal perfusion using magnetised blood as endogenous contrast and investigators have validated this technique previously in both individuals with and without kidney disease. Diffusion tensor imaging (DTI) is another modality of non-contrast MRI which allows measurement of 'stiffness' of renal transplants, which represents long term scarring and fibrosis. The investigators intend to follow up people receiving a kidney transplant for one year, collecting samples of blood, urine, and performing MR imaging at 3 time points, in order to investigate novel biomarkers of transplant function and dysfunction.