To evaluate the damage of renal function in CIAKI rats at 3T: using ASL and BOLD MRI.

Purpose: To investigate noninvasive arterial spin-labeling (ASL) and blood oxygen level-dependent imaging (BOLD) sequences for measuring renal hemodynamics and oxygenation in contrast induced acute kidney injury (CIAKI) rat.

Materials And Methods: Thirteen SD rats were randomly grouped into CIAKI group and control group. Both ASL and BOLD sequences were performed at 24 h preinjection and at intervals of 0.5, 12, 24, 48, 72, and 96 h postinjection to assess renal blood flow (RBF) and relative spin-spin relaxation rate (R2(*)), respectively.

Results: For the CIAKI group, the value of RBF in the cortex (CO) and outer medulla (OM) of the kidney was significantly decreased (P < 0.05) at 12-48 h and regressed to baseline level (P = NS) at 72-96 h. In OM, the value of R2(*) was increased at 0.5-48 h (P < 0.05) and not statistically significant (P = NS) at 72 and 96 h.

Conclusions: RBF in OM and CO and oxygen level in OM were decreased postinjection of CM. ASL combining BOLD can further identify the primary cause of the decrease of renal oxygenation in CIAKI. This approach provides means for noninvasive monitoring renal function during the first 4 days of CIAKI in clinical routine work.