Nonthermal effects of ultrasound include which of the following?

Nonthermal effects of ultrasound include which of the following?

• A. Increase vascular permeability
• B. Increase tissue temperature
• C. Decrease blood flow
• D. Tissue necrosis

Answer: (A)

Nonthermal ultrasound works by mechanical effects rather than heating, typically using pulsed, low-intensity settings. These mechanical actions—like stable cavitation and acoustic streaming—stimulate cells and the microvasculature to become more permeable. Increased vascular permeability allows better exchange of nutrients, inflammatory mediators, and fluids, which supports the healing process without raising tissue temperature. That’s why increased vascular permeability is the best choice for the nonthermal effects of ultrasound. In contrast, increasing tissue temperature is a thermal effect, not nonthermal. Decreasing blood flow is not a typical goal of therapeutic ultrasound, and tissue necrosis reflects tissue destruction from excessive energy, which is not a desired nonthermal outcome.

Nonthermal ultrasound works by mechanical effects rather than heating, typically using pulsed, low-intensity settings. These mechanical actions—like stable cavitation and acoustic streaming—stimulate cells and the microvasculature to become more permeable. Increased vascular permeability allows better exchange of nutrients, inflammatory mediators, and fluids, which supports the healing process without raising tissue temperature. That’s why increased vascular permeability is the best choice for the nonthermal effects of ultrasound.

In contrast, increasing tissue temperature is a thermal effect, not nonthermal. Decreasing blood flow is not a typical goal of therapeutic ultrasound, and tissue necrosis reflects tissue destruction from excessive energy, which is not a desired nonthermal outcome.