We evaluated the effect of lipiodol on the MR image by using dynamic MR imaging (MRI) with an intraarterial lipiodol injection in the VX-2 tumor. The signal intensity of the tumor had been risen gradually during the dynamic MRI, using T 1-weighted Spin Echo techniques. The high intensity areas on the dynamic MRI nearly corresponded with the lipiodol accumulated areas on CT. On the micrograph, no necrosis or degeneration of the tumor cell was visible. We conclude that the presence of lipiodol will affect the signal intensity of T 1-weighted MR images.