Time course study on the effects of iodinated contrast medium on intrarenal water transport function using diffusion-weighted MRI

Abstract

To assess the effects of intravenous-injected iodinated contrast medium (CM) on intrarenal water diffusion using noninvasive diffusion-weighted MRI (DW-MRI). Ten New Zealand White rabbits were randomized to receive a 6 mL/kg body weight intravenous injection of clinically used iopamidol-370 (n = 7) or an equivalent amount of 0.9% physiological saline (n = 3). A sequential DW-MRI was performed to estimate the intrarenal apparent diffusion coefficient (ADC) at 24 h before and 1 h, 24 h, 48 h, and 72 h after administration. Iopamidol produced a progressive ADC reduction in inner stripes of the renal outer medulla (IS) by 13.92% (P = 0.05) at 1 h, 17.52% (P = 0.02) at 24 h, 20.23% (P = 0.01) at 48 h and 16.31% (P = 0.04) at 72 h after injection. Cortical ADC was decreased by 14.14% (P = 0.01) at 48 h and 14.12% (P = 0.01) at 72 h after injection. Iopamidol produced slight decrease of ADCs in outer stripes of the outer medulla (OS) and inner medulla (IM) of kidney but without statistical difference. In control group, no significant ADC changes was observed in each anatomic compartment due to saline injection (P > 0.05). As demonstrated by DW-MRI, intravenous iopamidol injection resulted in a successive reduction of intrarenal water diffusion, particularly in IS of kidney. This MR technique may be used as a noninvasive tool to perform a time course study of the pathogenesis associated with contrast-induced nephropathy (CIN).