MRI Monitoring of Skull-Base Heating in Transcranial Focused Ultrasound Ablation

Yuexi Huang¹, Junho Song¹, Kullervo Hynynen^1,2

In transcranial focused ultrasound ablation, the heating of the outer skull surface has been reduced by a hemispherical design of phased-array transducers and active cooling of the skull surface with water circulation. However, the potential heating of the skull base has not been brought into much attention. In this work, experiments were performed with a MR-guided transcranial focused ultrasound system on a full human skull sample to investigate the heating of the skull base. MR thermometry was applied to measure the temperature change of the phantom adjacent to the skull base. The distance of the foci to the bone was varied to measure a safety margin for avoiding significant skull base heating.