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

PLoS One. 2012;7(4):e35509. doi: 10.1371/journal.pone.0035509. Epub 2012 Apr 20.

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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Female
  • Hyperthermia, Induced*
  • Magnetic Resonance Imaging*
  • Mammary Neoplasms, Experimental / therapy*
  • Mice
  • Models, Biological
  • Neoplasm Transplantation
  • Soy Foods
  • Temperature
  • Thermometers*
  • Ultrasonic Therapy*
  • Water

Substances

  • Water