Impact of ischemia duration on MRI-derived perfusion parameters in a mouse kidney transplant model

Cold ischemia during kidney transplantation induces ischemia-reperfusion injury with endothelial dysfunction, capillary leak, and impaired perfusion. Its duration critically determines graft outcome. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) enables noninvasive assessment of renal microcirculation and may indicate ischemic injury. We evaluated the impact of ischemia duration on DCE-MRI-derived perfusion parameters in renal transplants in mice.

Procedures were approved by the local institutional animal care and use committee. A total of 15 C57BL/6 mice underwent kidney transplantation and were assigned to a short or prolonged cold ischemia group. DCE-MRI was performed to assess renal perfusion. Imaging was conducted at a mean of 268 ± 30 days (mean ± standard deviation) after transplantation. Perfusion parameters were calculated using the Patlak model, which provides the plasma volume fraction (v_p), reflecting renal blood volume and perfusion, and the volume transfer constant (K^trans), characterizing the rate of contrast agent extravasation from capillaries into the extravascular extracellular space.

Significant differences were observed in the K^trans parameter of transplanted kidneys between groups. The median K^trans (mL/100 mL/min) was significantly higher in the 16-h group (2.87, interquartile range 2.45-3.03) versus the 30-min group (0.91, 0.90-1.42; p = 0.008). Median v_p (mL/100 mL/min) was non-significantly lower in the 16-h group (21.89, 17.28-23.22) versus the 30-min group (29.02, 24.99-37.15; p = 0.151).

Cold ischemia with 16-h duration was associated with significantly higher K^trans values in kidney transplants, reflecting significantly increased vascular permeability. DCE-MRI provides a sensitive tool for detecting ischemia-induced microvascular dysfunction.

Quantitative DCE-MRI detects microvascular injury after 16-h cold ischemia in kidney transplants in mice, supporting its potential as a noninvasive tool to assess graft integrity and guide interventions aimed at improving long-term transplant outcomes.

The duration of ischemia critically affects endothelial integrity and perfusion characteristics in a mouse kidney transplant model. Prolonged 16-h ischemia leads to increased vascular permeability, indicating more severe endothelial and microcirculatory injury in transplanted kidneys. DCE-MRI enables sensitive detection of subtle ischemia-related microvascular alterations, supporting its value for noninvasive graft assessment.