PURPOSE: To determine MRI features of tumor response in the early phase of preoperative chemotherapy in malignant tumors after intraarterial chemotherapy of VX-2 tumor in the rabbit thigh. MATERIALS AND METHODS: VX-2 tumors were induced in the thighs of eleven New Zealand white rabbits and intraarterial infusion of Cis-Platinum (3mg/kg) was performed in six. Pre- and post-contrast enhanced MR images and angiographies were obtained prior to and two weeks after chemotherapy. Five rabbits with VX-2 tumors were imaged at these same interval. Difference in MRI changes between the two groups were analysed and MRI findings were compared with angiographic and histologic findings. RESULTS: All VX-2 tumors showed rapid extensive necrosis, the most prominent MRI change in the chemotherapeutic group was decreased thickness of the enhancing rim which in the control group had increased (p = 0.083 and p = 0.374, respectively). The enhancing rim reflected the peripheral capsule with surrounding edema, inflammatory change, and tumors which were histologically viable. On angiography, it coincided with tumor staining. Change in tumor size was not significantly different between the two groups. In the chemotherapeutic group, a marginal necrotic band was the most prominent histologic feature. CONCLUSION: In the VX-2 tumor, chemotherapeutic response is seen on MRI as decreased thickness of the rim, and this reflects the tumor capsule and viable tumors. MRI can provide guidance in planning the treatment of malignant soft tissue tumors.