Monitoring accurate MR guided focused ultrasound hyperthermia treatments with a k-space based B0 correction thermometry technique

Motivation: Accurate MR thermometry methods are critical to the successful delivery of hyperthermia thermal therapy treatments. Goal(s): Evaluate a k-space based B0 correction technique for MR thermometry in MR guided focused ultrasound hyperthermia treatments. Approach: The performance of a previously developed thermal controller was evaluated using 3D PRF MR thermometry both with and without k-space field drift correction in phantom and in vivo rabbit undergoing MRgFUS hyperthermia treatment. The MRTI precision was also evaluated in a single human subject under non-heating conditions. Results: Drift corrected MRTI improved targeting accuracy of a PID controlled hyperthermia treatment in both phantoms and rabbits. Impact: Accurate MR thermometry is critical to the successful delivery of hyperthermia treatments, where a fraction of degree accuracy can impact treatment outcome. Implementing a k-space based B0 correction technique achieves substantially improved accuracy in MR guided focused ultrasound hyperthermia treatments.