MRI detects tubulointerstitial changes in mouse models of radiation-induced nephropathy.

Abstract

PURPOSE: We hypothesized that radiation-induced tubulointerstitial changes in the kidney can be assessed using MRI-based Trelaxation time measurements. METHODS: We performed MRI, histology, and serum biochemistry in two mouse models of radiation nephropathy: one involving external beam radiotherapy and the other using internal irradiation with an &#x3b1;-particle-emitting actinium-225 radiolabeled antibody. We compared the mean Tvalues of different renal compartments between control and external beam radiotherapy or &#x3b1;-particle-emitting actinium-225 radiolabeled antibody-treated groups and between the two radiation-treated groups using a Wilcoxon rank-sum test. RESULTS: Significantly higher Tvalues were found in the cortex and outer stripe of the outer medulla in all treated animals compared with the control group (p&#x2009;<&#x2009;0.05). In addition, these changes in Twere observed before any changes in serum parameters, animal body weight, and kidney volume occurred. CONCLUSION: Tmapping is sensitive to radiation-induced tubulointerstitial changes in the kidney.