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

PURPOSE: We hypothesized that radiation-induced tubulointerstitial changes in the kidney can be assessed using MRI-based T2 relaxation 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 α-particle-emitting actinium-225 radiolabeled antibody. We compared the mean T2 values of different renal compartments between control and external beam radiotherapy or α-particle-emitting actinium-225 radiolabeled antibody-treated groups and between the two radiation-treated groups using a Wilcoxon rank-sum test.

RESULTS

Significantly higher T2 values were found in the cortex and outer stripe of the outer medulla in all treated animals compared with the control group (p < 0.05). In addition, these changes in T2 were observed before any changes in serum parameters, animal body weight, and kidney volume occurred.

CONCLUSION

T2 mapping is sensitive to radiation-induced tubulointerstitial changes in the kidney.