In a small series, CEUS was found to be helpful in differentiating the underlying causes of delayed graft dysfunction [30]. CEUS can confirm transplant RAS and also aids in the assessment of the degree of stenosis [31]. Currently, CEUS has not received approval by the U.S. Food and Drug Administration. US-based elastography is another tool that may aid in the noninvasive assessment of CAN. The parenchymal stiffness measured by the transient elastography technique correlates with underlying histologic interstitial fibrosis [32]. Unfortunately, kidney stiffness is not just related to the degree of fibrosis but is also related to functional and mechanical parameters [33]. Although this new tool has promise, further validation is needed in clinical practice. Computed Tomography and Computed Tomography Angiography The utilization of CT of the abdomen and pelvis with contrast should be considered in conjunction with the risks of nephrotoxicity from iodinated contrast [34]. It may be beneficial in evaluating renal masses, perinephric fluid collections, and post-transplant lymphoproliferative disease. Renal Transplant Dysfunction In patients with suspected vascular complications (RAS, RVT, PSA, AVF), CTA can provide a detailed anatomic depiction prior to undergoing percutaneous angiography. Data about the usefulness of CT in evaluating transplant vascular complications are limited. Helck et al [35] found abnormalities on CT in 42% of cases when US was unremarkable. These included renal infarction, renal vein stenosis, and AVF. Rountas et al [36], in their study of native kidney vasculature, found that CTA and MRA have comparable negative predictive accuracy in evaluating suspected RAS. They found that CTA had 94% sensitivity, 93% specificity, 71% PPV, and 99% NPV. A small series by Gaddikeri et al [37] that compared CTA and MRA in the assessment of transplant RAS also demonstrated little difference between the modalities.
Renal Transplant Dysfunction. In a small series, CEUS was found to be helpful in differentiating the underlying causes of delayed graft dysfunction [30]. CEUS can confirm transplant RAS and also aids in the assessment of the degree of stenosis [31]. Currently, CEUS has not received approval by the U.S. Food and Drug Administration. US-based elastography is another tool that may aid in the noninvasive assessment of CAN. The parenchymal stiffness measured by the transient elastography technique correlates with underlying histologic interstitial fibrosis [32]. Unfortunately, kidney stiffness is not just related to the degree of fibrosis but is also related to functional and mechanical parameters [33]. Although this new tool has promise, further validation is needed in clinical practice. Computed Tomography and Computed Tomography Angiography The utilization of CT of the abdomen and pelvis with contrast should be considered in conjunction with the risks of nephrotoxicity from iodinated contrast [34]. It may be beneficial in evaluating renal masses, perinephric fluid collections, and post-transplant lymphoproliferative disease. Renal Transplant Dysfunction In patients with suspected vascular complications (RAS, RVT, PSA, AVF), CTA can provide a detailed anatomic depiction prior to undergoing percutaneous angiography. Data about the usefulness of CT in evaluating transplant vascular complications are limited. Helck et al [35] found abnormalities on CT in 42% of cases when US was unremarkable. These included renal infarction, renal vein stenosis, and AVF. Rountas et al [36], in their study of native kidney vasculature, found that CTA and MRA have comparable negative predictive accuracy in evaluating suspected RAS. They found that CTA had 94% sensitivity, 93% specificity, 71% PPV, and 99% NPV. A small series by Gaddikeri et al [37] that compared CTA and MRA in the assessment of transplant RAS also demonstrated little difference between the modalities.