Renal scintigraphy for post-transplant monitoring after kidney transplantation

Background: Clinicians use several diagnostic modalities to recognize post-transplant complications, such as acute tubular necrosis, acute rejection, urologic and vascular complications. Currently, there is no consensus about the best procedural approach to evaluate post-transplant renal dysfunction. Renal needle-biopsy is often required, however, this is invasive and may lead to sample errors and complications, and most clinicians prefer using one of the noninvasive diagnostic modalities. Methods: A systematic literature search was performed using PubMed, EMBASE, the Cochrane Library, MEDLINE (OvidSP), Web of Science, and Google Scholar to identify relevant articles. This review provides a literature overview of the technical aspects, new developments and clinical value of renal scintigraphy (RS), after kidney transplantation. Additionally, the advantages and limitations of RS in comparison to other diagnostic modalities are addressed. The study protocol is registered with PROSPERO, protocol number CRD42017078391. Results: A total of 32 studies were included. Studies were categorized in the following groups: tracer pharmacokinetics; acute rejection and acute tubular necrosis; vascular complications; urological complications; postoperative fluid collections; early transplant outcomes; one-year transplant outcomes. Conclusions: Several studies have described the use of RS for the diagnosis of acute rejection, however, differentiating between rejection and acute tubular necrosis remains difficult. For the diagnosis of vascular complications, RS has been described as an alternative for invasive procedures. For urologic complications, studies support the use of RS in combination with routine ultrasonography (US) surveillance. For the diagnosis of postoperative fluid collections, RS provides information to differentiate lymphoceles and urinomas. Altogether, RS should be considered in case of non-acute complications, and if US provides insufficient results