Ultrasound Guided Procedures: 

Fine Needle Guided Aspirates (FNAs):  Small needles are used to get cytology (groups of cells) samples for analysis.  Using ultrasound guidance allows for more precise placement of the needles within the target of interest.  This may allow for sampling of a target that would not be safe to sample blindly.

Centesis:  A needle and syringe are used to remove fluid from the body (such as the urinary bladder, gallbladder, pleural space or peritoneum) for analysis.  Ultrasound guidance allows for more precise positioning of the needle during this procedure which may also allow for smaller amounts of fluid to be sampled than would be possible without ultrasound.  

Tru-Cut Biopsy:  A tissue biopsy needle is used to obtain samples of an organ and/or mass for histopathology.  This often requires the patient to be under anesthesia and has a greater potential for serious complication (such as uncontrolled bleeding or puncture of adjacent structures which may be life threatening) than FNAs but provides pieces of tissue rather just cells for analysis.