CENEPSIA: feasibility of an ultrasound device to treat epileptic refractory foci

Purpose In addition to its imaging applications, ultrasonography is increasingly used to treat several health conditions. Using ultrasound and a brain tissue phantom, we are exploring the feasibility of neurostimulation or neuroablation to treat refractory epilepsy foci. Methods Literature review and result of our laboratory measurements: ultrasound power, ultrasound beam geometry, and temperature increase caused by ultrasound-focused irradiation. We used continuous waves with powers of 6, 9, 12, 15, and 24 W, adjusted to produce intensities of 0.5, 0.75, 1, 1.25, and 2 W·cm −2 in a volume of 0.025 cm 3 for 320 s at 100% duty cycle. Results Twelve reports, including ours, reflected the international experience on the topic. The measured power in the phantom or tissue ranged from 0.003 to 115.8 W·cm −2 , across the reviewed papers. We measured in our intervention volume of 0.025 cm 3 , an energy of 15.2 to 60.8 W·s and after 320 s of continuous irradiation and a temperature increase of 2.3 to 3.6 °C. Conclusion Focused ultrasound irradiation appears to have great potential as a treatment for refractory epilepsy, either by blocking epileptic foci or by thermal ablation. Dissipating different amounts of energy in a small volume of phantom opens the way to both ultrasound ablation and neuromodulation. Further research using specific phantom of brain tissue, ex vivo tissue, and cranial bone will lead to the specification of physical parameters to be used, such as power, frequency, intensity, duty cycle, and energy deposition rate.