الفهرس | Only 14 pages are availabe for public view |
Abstract Renal transplantation is the preferred treatment for ESRD patients, because it provides a better life quality and long-term survival when compared to the lifelong dialysis. There is continuous improvement in the surgical techniques and the immunosuppressive drugs, however, surgical and medical complications can still occur. The most common medical causes for graft dysfunction are AR, ATN, immunosuppressive nephrotoxicity and graft infection. Early characterization and monitoring of dysfunction after kidney transplantation by imaging modalities like US, Doppler, CT and MRI are crucial to allow effective treatments and to improve the outcome. However, these complications show non-specific appearance on conventional imaging modalities, and the graft biopsy is still the gold standard for differentiation between them. MRI become an important non-invasive diagnostic imaging modality in evaluation of renal transplants due to its high contrast resolution providing excellent anatomic images without ionizing radiation or iodinated contrast injection. Beside its excellent morphological details, MRI also provides advanced techniques for assessment of different renal functional parameters. DWI is a promising powerful non-invasive technique that provides information on the renal microstructure and function depending on the microscopic random movement of the water molecules within the tissue with its quantitative parameter “ADC”, that describes the spatial water behavior reflecting the intrinsic unique tissue characteristics, and so, it is sensitive to alterations in the renal interstitium (like edema, fibrosis or cellular infiltration) by different renal diseases. The kidney is characterized by its anisotropic architecture, due to the radial distribution within the medulla, leading to directed and anisotropic diffusion. Measurement of the diffusion direction might be more sensitive to abnormalities in renal microstructure and function than measurement of global diffusion. DTI is an advanced technique of diffusion imaging identifying the preferred direction of molecule motion. It is acquired by applying at least six diffusion-sensitizing directions, to quantify the degree of tissue anisotropy by generating FA value, which is the quantitative parameter that describes the amount and degree of diffusion anisotropy. |