Magnetic Resonance-Visible Polypropylene Mesh for Pelvic Organ Prolapse Repair

Abstract

Aim: To develop a magnetic resonance (MR)-visible mesh using iron oxides and prove visibility. Methods: In a phantom study, a suitable iron oxide, Fe₃O₄ [iron(II,III) oxide] and FeOOH [iron(III) oxide-hydroxide], concentration was determined using relaxometric MR measurements of the transverse relaxation rates R2 and R2*. Next, a nonabsorbable mesh was designed from the MR-visible threads woven into a polypropylene mesh. The mesh was implanted into a fresh female cadaver via the transobturator route, and MR visibility was assessed with various MR pulse sequences in a clinical 3-tesla system. Results: Optimal contrast was achieved with Fe₃O₄ at 0.2 weight-% in all imaging sequences, and the optimal contrast was achieved in a 3D spoiled gradient-echo (fast low-angle shot) acquisition. In this concentration range the apparent transverse relaxation rate R2* is below 10 ms. The mesh was visible in the cadaver on T1-weighted 3D spoiled gradient-echo images and T1-weighted fast spin-echo images. Conclusion: Mesh materials can be manufactured to be visible on MR with a negative contrast. Fe₃O₄ meshes could simplify follow-up examinations and help diagnose origins of postsurgical lesions after urogynecological procedures with mesh material.