This is a specific surgical technique, and as such can be expected to vary in instrumentation according to the manufacturer and experience, and to be used in differing manners according to the surgeon.
Liposuction is the removal of fat by suction. That sounds such a simple thing to do that all kinds of people attempt it, and all kinds of unfortunate results are found, varying from unsightly appearance to death.
There are certain areas of the body which are cosmetically unsightly, but because of a high content of fibrous tissue as well as the excess fat, are difficult to correct satisfactorily by simple liposuction. Typical of these are gynecomastia in the male and the upper back in either sex.
Ultrasound does more than make pictures of the fetus, used in a different way it is a method of focussing energy at a small area, and is widely used by physical therapists for this purpose; absorbed energy causes heat. Fat at human temperatures is in a liquid state contained with the cell wall. When the appropriate tool is used, ultrasound will liberate the fat from its containing cell envelope, and it can then be removed by suction-assisted lipoplasty.