Magnetic Resonance Imaging Thermography with Uniform Gd Microstructures

Magnetic resonance imaging is an important technique in imaging living tissue and composite structures. Many medical procedures now use MRI as a critical component including MRI guided thermal ablation therapy used to treat cancer. Such procedures require real-time, spatially and thermally accurate temperature maps. We demonstrate an MRI temperature contrast agent consisting of uniform gadolinium microstructures dispersed within a media. We report on the performance of 6 micron wide, disk-shaped Gd microstructures passivated by a layer of chromium. A SQUID magnetometer was used to determine the mass magnetization of these disks. The temperature dependence of the mass magnetization was then correlated to the nuclear magnetic resonance linewidth broadening of water protons in the presence of Gd disks. We used this correlation to demonstrate the MRI image brightness of the Gd microstructures suspended in a tissue-mimicking phantom can be related to the temperature of the sample indicating these Gd disks are a good candidate for use as an MRI temperature contrast agent.