An aspiration is the removal of fluid from a particular part of your body, while a biopsy removes cells. The procedure may be done to further examine the fluid or cells in a laboratory. Guiding by ultrasound is to increase accuracy and efficiently remove the fluid or cells from the tested area, particularly if the area is deeper within the body. An aspiration/biopsy is an incision-free alternative to get a better look at a suspicious area of the body.