T2-based Temperature Monitoring in Bone Marrow

• Proton resonant frequency shift (PRF) thermometry fails to detect temperature change in tissues with high lipid content, such as bone marrow.
• Current clinical protocols rely on measurement of temperature change of adjacent muscle
• Poor accuracy of temperature measurement, sub-optimal ablation
• Here, we developed T2-based thermometry to monitor the temperature in bone marrow during focused ultrasound ablation.
• We measured a T2 elevation of 269 ms. Assuming the T2/temp coefficient of 7 ms/°C, this corresponds to a temperature rise of 38°C. The ex-vivo experiment shows that it takes 10-15 minutes for the marrow to return to the baseline temperature.
• The in-vivo experiment showed excellent correspondence between the area of T2 elevation in marrow during the ablation and the resulting non-enhancing area in the post-contrast images.

Publication

• E Ozhinsky, M Han, M Bucknor, R Krug, V Rieke. T2-based temperature monitoring in bone marrow for MR-guided focused ultrasound. Journal of Therapeutic Ultrasound, 17;4:26, 2016.