Magnetic resonance imaging-guided focused ultrasound synovectomy.

<bold>Objective: </bold>To investigate the feasibility of magnetic resonance imaging (MRI)-guided high power focused ultrasound (FUS) to perform synovectomy noninvasively.<bold>Methods: </bold>Five New Zealand white male rabbit knees with experimentally induced arthritis underwent MRI-guided thermal surgery by high power (60 W/10 s) sonication. Evidence of tissue coagulation was monitored during the procedure and confirmed by gross and microscopic evaluation and MRI.<bold>Results: </bold>Partial synovectomy was performed in five animals. Necrotized synovial tissue was observed on gross and microscopic evaluation. Visible signal intensity alterations including high signal intensity on T2-weighted (T2W) images and lack of contrast-enhancement on T1-weighted (T1W) post-contrast, post-sonication images were characteristic and reproducible.<bold>Conclusion: </bold>Our results demonstrate the ability of high power sonication to destroy synovial tissue in vivo. [ABSTRACT FROM AUTHOR]