Wearable Coil for Knee Flexion MRI

Musculoskeletal MRI can characterize articular and patellar cartilage and help detect degradation related to osteoarthritis. While clinical knee MRI is performed under static conditions, research has shown that weight bearing and kinetic imaging provides new information on ligament and meniscus stress and post-load cartilage recovery dynamics [1] – [3] . Such experiments are difficult to perform or are compromised by clinical knee coils whose mechanical rigidity is intended to restrict, rather than enable, flexion motion. The legacy of rigid coils can be traced to the desire to maximize sensitivity, mechanical robustness, and coil decoupling, which has been accomplished using rigid copper loops (characterized by high conductivity) packaged in rigid protective shells. Several groups have developed groundbreaking wearable coils that accommodate flexion (see for example [4] , [5] ). While extremely promising, many flexible coils utilize non-standard, expensive, or proprietary conductors. It is also challenging to decouple coils in the flexible regime due to their fluid geometric relationship.