E2680. MR Imaging of Early Parenchymal Complications of Renal Allografts: Added Value of DWI to Dynamic Contrast Enhanced MR and T2W Imaging
  1. Kanika Gupta; University of Arizona
  2. Gabriel Duhancioglu; University of Arizona
  3. Hina Tiwari; University of Arizona
Intrinsic renal parenchymal complications as a cause for graft dysfunction are considered after exclusion of extra parenchymal complications related to vascular structures and collecting system. Common causes of early graft dysfunction include acute rejection, accelerated acute rejection, acute tubular necrosis, cyclosporine toxicity and infection. Magnetic resonance (MR) imaging offers a noninvasive tool to study graft parenchyma while simultaneously excluding other etiologies of graft rejection. Timely diagnosis of early parenchymal complications as acute pyelonephritis and acute rejection is crucial for management decisions and preservation of graft functionality. Superior soft tissue resolution of MR provides exquisite details about the parenchymal morphology on single shot T2WI. The dynamic pre and postcontrast fat saturated 3D gradient echo T1WI images (3D GRE-T1WI) and diffusion weighted images (DWI) provide functional information. DWI adds value by quantifying the combined effects of capillary perfusion and diffusion which gives significant insights for non-invasive detection and monitoring of early parenchymal complications specially related to microischaemic changes in the kidney with high accuracy.

Educational Goals / Teaching Points
This exhibit presents a systematic review of body MRI protocol. Highlight key MRI sequences used to review findings of parenchymal complications of graft dysfunction, with special emphasis on the role of DWI. To illustrate the spectrum of MR imaging features of various causes (acute rejection, accelerated acute rejection, acute tubular necrosis, cyclosporine toxicity and uncomplicated and complicated pyelonephritis). To highlight salient MR features of each etiology, and discuss mimics and challenges in diagnosis.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Imaging Technique: T2 in axial, coronal and sagittal planes; isometric T2 SPACE; fat saturated precontrast and dynamic contrast enhanced (DCE) T1 3D gradient-echo, providing time-resolved perfusion imaging through the renal allograft. DWI was acquired at a high b-value of 800 mm2.

MR imaging with excellent soft tissue contrast resolution provides a comprehensive noninvasive imaging modality in diagnoses of early parenchymal complications of renal allograft dysfunction. In multidisciplinary care of the transplant patient, radiologists play an integral role in aiding timely and accurate diagnosis causes graft complications thereby in guiding prompt management decisions.