Urinary NGAL and IGFBP-7 levels did not change significantly in the non-CI-AKI group at each of the six time points; however, the levels of urinary TIMP-2 and [IGFBP-7]*[TIMP-2] were slightly elevated at 2 h, but significantly lower than those in the CI-AKI group at the same time point and would be decreased to the precontrast level at 6 h. This evidence concerns the gene TIMP2 and acute kidney injury.