(SA) The spatial average intensity is the acoustic power within the beam, divided by the beam area.

See Time Average Intensity.

(MIP) Angiography (Doppler) images can be processed by Maximum Intensity Projection to interactively create different projections. Although the maximum intensity projection (MIP) post processing algorithm is sensitive to high signal from inflowing spins as used in MRI, it is also sensitive to high signal of any other etiology as used in ultrasound imaging. The MIP connects the high intensity dots of the blood vessels in three dimensions, providing an angiogram that can be viewed from any projection. Each point in the MIP represents the highest intensity experienced in that location on any partition within the imaging volume.
For complete interpretation the base slices should also be reviewed individually and with multiplanar reconstruction (MPR) software. The MIP can then be displayed in a CINE format or filmed as multiple images acquired from different projections.

See also 3D Ultrasound.

(LIPU / LIUS) Low intensity pulsed ultrasound is a form of mechanical power that is transmitted through and into tissues as an acoustic pressure wave. Low intensity pulsed ultrasound is often used in musculoskeletal and joint ultrasound and has therapeutic benefits for healing of (fresh) fractures, those that demonstrate either a delayed union or nonunion, and soft tissue repair.

(HIFU / FUS) High intensity focused ultrasound is used in thermotherapy or thermoablation e.g., for the treatment of benign prostate hyperplasia or under study for the treatment of cancer.
An applied ultrasound probe (see transrectal sonography) focuses sound waves at one spot, elevating the tissue temperature to a point that the tissue destroys. Generally, lower frequencies (from 250 kHz to 2000 kHz) are used than for medical diagnostic ultrasound, but significantly higher time-averaged intensities.

See also Magnetic Resonance Guided Focused Ultrasound, Low Intensity Pulsed Ultrasound, and Lithotripsy.