MRI of renal oxygenation and function after normothermic ischemia-reperfusion injury.

ABSTRACT

The in vivo assessment of renal damage after ischemia-reperfusion injury, such as in sepsis, hypovolemic shock or after transplantation, is a major challenge. This injury often results in temporary or permanent nonfunction. In order to improve the clinical outcome of the kidneys, novel therapies are currently being developed that limit renal ischemia-reperfusion injury. However, to fully address their therapeutic potential, noninvasive imaging methods are required which allow the in vivo visualization of different renal compartments and the evaluation of kidney function. In this study, MRI was applied to study kidney oxygenation and function in a murine model of renal ischemia-reperfusion injury at 7 T. During ischemia, there was a strongly decreased oxygenation, as measured using blood oxygen level-dependent MRI, compared with the contralateral control, which persisted after reperfusion. Moreover, it was possible to visualize differences in oxygenation between the different functional regions of the injured kidney. Dynamic contrast-enhanced MRI revealed a significantly reduced renal function, comprising perfusion and filtration, at 24 h after reperfusion. In conclusion, MRI is suitable for the noninvasive evaluation of renal oxygenation and function. Blood oxygen level-dependent or dynamic contrast-enhanced MRI may allow the early detection of renal pathology in patients with ischemia-reperfusion injury, such as in sepsis, hypovolemic shock or after transplantation, and consequently may lead to an earlier intervention or change of therapy to minimize kidney damage.