Three-dimensional organ-resolved modeling of ultrasound-induced acoustic and thermal effects in the mouse abdomen.

Therapeutic ultrasound offers a noninvasive approach for modulating metabolic function, yet spatially heterogeneous acoustic and thermal responses in the abdomen remain poorly understood. Here, we developed a three-dimensional, organ-resolved computational model of ultrasound propagation and heat transfer in the mouse abdomen to systematically investigate the effects of ultrasound parameters, body composition, blood perfusion, and gastrointestinal gas on acoustic energy deposition and tissue heating. Simulations were performed using ultrasound exposures with input intensities of 1-5 W/cm2, frequencies of 400-1200 kHz, duty cycles of 10%-100%, and sonication durations of 5 minutes. Increasing duty cycle or input intensity produced monotonic rises in peak temperature, while frequency and lean versus obese body composition had modest effects. Incorporation of organ-specific blood perfusion reduced maximum temperatures across all tissues, with the largest reduction in the kidney (4.2%) and smaller reductions in the pancreas (2.7%), stomach (2.2%), liver (2.0%), and spleen (1.7%). The presence of intragastric air, modeled as an air-filled stomach cavity and compared to the baseline soft-tissue stomach model, redistributed acoustic energy. Peak intensity increased in the kidney (＋0.4 W/cm2), stomach (＋2.0 W/cm2), and liver (＋1.3 W/cm2), while modest decreases were observed in the pancreas (-0.2 W/cm2) and spleen (-0.1 W/cm2). Overall, these results provide quantitative insight into organ-specific ultrasound energy deposition and heating in the mouse abdomen. The findings highlight the moderating role of blood perfusion and the potential influence of gastrointestinal gas on localized acoustic exposure, offering guidance for optimizing ultrasound parameters in preclinical studies while maintaining thermal safety.