ABSTRACT
Background:
There were no effective noninvasive
methods to
diagnose renal
ischemia-reperfusion injury (IRI), which is a major clinical problem. The objective of this study was to explore the feasibility of the quantitative susceptibility mapping (QSM)
technique in evaluating the dynamic changes in the renal IRI process.
Methods:
A total of 36
New Zealand rabbits were randomly assigned to the IRI group (n=30) and the sham group (n=6). All
rabbits underwent
magnetic resonance imaging (MRI) examination, including T2-weighted imaging and QSM before the operation (pre-IRI) and 1, 12, 24, and 48 h after the operation (IRI-1h, IRI-12h, IRI-24h, and IRI-48h, respectively). Regions of interest were manually delineated in the outer medulla. All specimens were stained with
hematoxylin and
eosin (HE) and
glutathione peroxidase 4 (GPX4). The pathological score of renal
injury and the average optical density value of GPX4 were calculated. The repeated measurement
analysis of variance (
ANOVA) and Spearman correlation
analysis were used to compare the differences between the susceptibility values and determine the correlation.
Results:
In the IRI group, the susceptibility values of the outer medulla at the pre-IRI, IRI-1h, IRI-12h, IRI-24h, and IRI-48h
time points were (42.83±7.83)×10-3, (-5.33±6.28)×10-3, (6.50±3.94)×10-3, (12.00±3.74)×10-3, and (22.00±6.81)×10-3 ppm, respectively. The susceptibility values significantly differed among the different
time points (P<0.001). The susceptibility values had a negative correlation with the scores of
cell edema (ρ=-0.61; P=0.002) and the average optical density value of GPX4 (ρ=-0.70; P<0.001). The susceptibility values had a positive correlation with
iron content (ρ=0.79; P<0.001), the scores of
cell necrosis (ρ=0.71; P<0.001), interstitial
inflammation (ρ=0.60; P=0.002), cast (ρ=0.75; P<0.001), and the total pathological score of renal
injury (ρ=0.51; P=0.01).
Conclusions:
QSM can be used as a noninvasive
method to assess the dynamic changes of the outer medulla in the early stage of renal IRI in
rabbits.
