MR Guided High Intensity Focused Ultrasound Bone Ablation Assessed with MR, PET, and MDCT Imaging

Matthew Bucknor¹, Viola Rieke¹, Youngho Seo¹, Randall Hawkins¹, Mark Wilson¹, Sharmila Majumdar¹, Thomas M. Link¹, Maythem Saeed¹

MR-guided high intensity focused ultrasound (MRgHIFU) is a powerful technique for thermally ablating focal lesions. The purpose of this study was to clearly delineate post-treatment changes in bone following HIFU on MR, PET and MDCT imaging in a swine model. Two discrete ovoid lesions were created at each proximal diaphysis and distal metadiaphysis of the right femur. Follow-up imaging studies at five days demonstrated focal ovoid hypoenhancement and decreased radiotracer uptake (dynamic 18NaF-PET) which correlated precisely to the prescribed targets. CT failed to demonstrate the lesions. This study supports the usage of MRgHIFU in treating focal lesions in bone.