[HTML][HTML] Magnetic resonance thermometry at 7T for real-time monitoring and correction of ultrasound induced mild hyperthermia

BZ Fite, Y Liu, DE Kruse, CF Caskey, JH Walton… - PloS one, 2012 - journals.plos.org
BZ Fite, Y Liu, DE Kruse, CF Caskey, JH Walton, CY Lai, LM Mahakian, B Larrat, E Dumont
PloS one, 2012journals.plos.org
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 …
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.
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