title: Magnetic resonance thermometry at 7T for real-time monitoring and correction of ultrasound induced mild hyperthermia.
abstract: While Magnetic Resonance Thermometry (MRT) has been extensively utilized for non-invasive temperature measurement, there is limited data on the use of high field (≥7T) scanners for this purpose. MR-guided Focused Ultrasound (MRgFUS) is a promising non-invasive method for localized hyperthermia and drug delivery. MRT based on the temperature sensitivity of the proton resonance frequency (PRF) has been implemented in both a tissue phantom and in vivo in a mouse Met-1 tumor model, using partial parallel imaging (PPI) to speed acquisition. An MRgFUS system capable of delivering a controlled 3D acoustic dose during real time MRT with proportional, integral, and derivative (PID) feedback control was developed and validated. Real-time MRT was validated in a tofu phantom with fluoroptic temperature measurements, and acoustic heating simulations were in good agreement with MR temperature maps. In an in vivo Met-1 mouse tumor, the real-time PID feedback control is capable of maintaining the desired temperature with high accuracy. We found that real time MR control of hyperthermia is feasible at high field, and k-space based PPI techniques may be implemented for increasing temporal resolution while maintaining temperature accuracy on the order of 1°C.
authors.affiliation: Department of Biomedical Engineering, University of California, Davis, Davis, California, United States of America.
authors.forename: Brett Z
authors.initials: BZ
authors.lastname: Fite
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Dustin E
authors.initials: DE
authors.lastname: Kruse
authors.forename: Charles F
authors.initials: CF
authors.lastname: Caskey
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Walton
authors.forename: Chun-Yen
authors.initials: CY
authors.lastname: Lai
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Mahakian
authors.forename: Benoit
authors.initials: B
authors.lastname: Larrat
authors.forename: Erik
authors.initials: E
authors.lastname: Dumont
authors.forename: Katherine W
authors.initials: KW
authors.lastname: Ferrara
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D005260:Female; D006979:Hyperthermia, Induced; D008279:Magnetic Resonance Imaging; D008325:Mammary Neoplasms, Experimental / Q000628:therapy*; D051379:Mice; D008954:Models, Biological; D009368:Neoplasm Transplantation; D045730:Soy Foods; D013696:Temperature; D013821:Thermometers; D014464:Ultrasonic Therapy; D014867:Water
chemical_list: D014867:Water