Quantitative image feedback for pulsed cavitational ultrasound therapy- histotripsy

Histotripsy is a well-controlled ultrasonic tissue ablation technology that mechanically and progressively fractionates soft tissue using cavitation. Significant ultrasound backscatter reduction occurs as the tissue in the treated volume is fractionated. This paper studies the quantitative correlation between the degree of histotripsy-induced tissue fractionation, as indicated by the percentage of remaining normal appearing nuclei, and the normalized backscatter intensity. Results show that both the normalized backscatter intensity and the percentage of remaining normal appearing nuclei in the treated area decrease exponentially with increasing number of pulses. A strong correlation exists between the degree of tissue fractionation and the normalized backscatter intensity. This quantitative feedback may allow the prediction of local clinical outcomes, i.e. when a tissue volume has been sufficiently treated.