MR imaging of soft-tissue changes after percutaneous transluminal angioplasty and stent placement.

PURPOSE: To evaluate the different tissue reactions at magnetic resonance (MR) imaging after balloon dilation and placement of covered and uncovered stents. MATERIALS AND METHODS: Contrast material-enhanced MR imaging was performed in 14 patients with polyester-covered nitinol stents, 10 patients with conventional metallic stents, and 12 patients who underwent peripheral percutaneous transluminal angioplasty. Lesions were located in the subclavian, iliac, femoral, and popliteal arteries. RESULTS: MR imaging demonstrated perivascular soft-tissue inflammation in 11 of 14 (79%) patients with polyester-covered stents. Eight (57%) of these patients showed clinical symptoms. No reaction was found among the group with uncovered stents and those who underwent peripheral percutaneous transluminal angioplasty. CONCLUSION: The polyester-covered nitinol stent can induce systemic and severe local reactions. These reactions seem to be specific to this type of stent. No definite cause has been established, although the ...