Assessment of renal allograft cortical perfusion in the early postoperative period using arterial spin labeling magnetic resonance imaging.

BACKGROUND: The early postoperative period is critical for patients who have undergone renal transplantation. This study aimed to quantify cortical perfusion in renal allografts during this period using arterial spin labeling (ASL) magnetic resonance imaging (MRI). METHODS: Between May and December 2014, ASL MRI was performed on 53 patients with renal allografts who were 2 to 4 weeks post-transplantation, as well as on 20 healthy volunteers. Recipients were stratified into two groups according to estimated glomerular filtration rate (eGFR): those with good allograft function (eGFR ≥60 mL/min/1.73 m2), and those with impaired allograft function (eGFR <60 mL/min/1.73 m2). Renal blood flow (RBF) values were compared across healthy controls and the two recipient groups. The correlation between RBF and eGFR was also evaluated. RESULTS: Mean cortical RBF was 389.9±61.2 mL/100 g/min in healthy controls, 295.0±67.9 mL/100 g/min in recipients with good allograft function, and 195.5±88.9 mL/100 g/min in recipients with impaired allograft function. Statistically significant differences in cortical RBF were observed among the three groups (P<0.001). A moderate positive correlation between eGFR and cortical RBF was identified among renal allograft recipients (R=0.62, P<0.01). CONCLUSIONS: Renal cortical perfusion in allografts during the early postoperative period was significantly reduced compared to healthy controls, particularly in cases of impaired allograft function. ASL MRI demonstrates potential as a non-contrast imaging modality for quantifying renal cortical perfusion in the post-transplant setting.