Abstract: PUB535
Evaluation of Allograft Rejection with MRI, Attenuation Diffusion Coefficient (ADC) Mapping: A Case Report
Session Information
Category: Transplantation
- 2102 Transplantation: Clinical
Authors
- Akram, Sami M., Loma Linda University, Loma Linda, California, United States
- Staton, Michael A., Loma Linda University, Loma Linda, California, United States
- Barba, Lilly M., Harbor-UCLA Medical Center, Torrance, California, United States
- Villicana, Rafael, Loma Linda University, Loma Linda, California, United States
Group or Team Name
- Transplant Nephrology and Radiology.
Introduction
The movement of water is the essence of life, and is central to kidney function. The kidney moves water by filtration, reabsorption, excretion, and secretion via aquaporin channels. Therefore, Diffusion-Weighted MRI Imaging with attenuation diffusion coefficient (ADC) maps can assess renal pathology but seldom utilized. Therefore, we report a case of allograft rejection evaluated by ADC map.
Case Description
A 26-year-old male with end stage kidney disease (ESKD) due to congenital kidney disease, had 0-mismatch diseased donor kidney transplant (DDKT), two years ago with thymoglobulin induction. He presented with oliguria of one week duration. He was non-complaint with therapy. Vital signs were within normal limits. Physical exam was remarkable for pitting leg edema. Laboratory exam showed serum creatinine of 9mg/dL; WBC 6.7 k/mcL; Hemoglobin, 8.3mg/dL; potassium 5.3mMol/L. Donor specific antibodies (DSA) were present. Allograft ultrasound showed mildly increased cortical echogenicity with mild pelviectasis. Renal indices were normal. MRI with ADC mapping showed uniformly low values in upper, mid and low consistent with restricted diffusion. Histology revealed acute Antibody mediated Rejection (AMR). Had good clinical respoonse to therapy.
Discussion
Diffusion-weighted imaging measures the Brownian motion of water molecules within a voxel by acquiring phase information of moving water molecules between the first and the second gradient MRI pulse sequence. Computer software generates ADC map. ADC is affected by the number of cells, the integrity of the cell membranes, and the amount of fibrosis, all of which restrict diffusion of water molecules. Ghar and Djasty et al described heterogeneity of ADC map in kidneys with acute tubular necrosis (ATN) when compared to kidneys with acute rejection (AR).T-cell and antibody mediated rejctions are high cellularity states, therefore ADC maps can be a useful tool in the initial evaluation and longitudinal follow-up transplant recipients. Further study of this modality is needed.