Magnetic resonance imaging-guided focused ultrasound synovectomy

Objective. To investigate the feasibility of magnetic resonance imaging (MR I)-guided high power focused ultrasound (FUS) to perform synovectomy noninv asively. Methods. Five New Zealand white male rabbit knees with experimentally induc ed arthritis underwent MRI-guided thermal surgery by high power (60 W/10 s) sonication. Evidence of tissue coagulation was monitored during the proced ure and confirmed by gross and microscopic evaluation and MRI. Results. Partial synovectomy was performed in five animals. Necrotized syno vial tissue was observed on gross and microscopic evaluation. Visible signa l intensity alterations including high signal intensity on T2-weighted (T2W ) images and lack of contrast-enhancement on T1-weighted (T1W) post-contras t, post-sonication images were characteristic and reproducible. Conclusion. Our results demonstrate the ability of high power sonication to destroy synovial tissue in vivo.