Magnetic resonance imaging of temperature changes during interstitial microwave heating: A phantom study

Abstract
Changes in magnetic resonance (MR) signals during interstitial microwave heating are reported, and correlated with simultaneously acquired temperature readings from three fiber‐optic probes implanted in a polyacrylamide gel phantom. The heating by a MR‐compatible microwave antenna did not interfere with simultaneous MR image data acquisition. MR phase‐difference images were obtained using a fast two‐dimensional‐gradient echo sequence. From these images the temperature‐sensitive resonant frequency of the 1H nuclei was found to decrease approximately by 0.008 ppm/°C. The method and results presented here demonstrate that noninvasive MR‐temperature imaging can be performed simultaneously with interstitial microwave thermal treatment.