Abdominal Ultrasound

     Ultrasound is an excellent technique for evaluation of the peritoneal and retroperitoneal organs that cannot always be distinguished with survey radiographs, and is a non-invasive procedure that can be used to assess changes within organs and tissues based on differences in acoustic impedance.  In most cases a complete abdominal ultrasound is indicated.  Localized exams are indicated for early pregnancy checks and fetal viability for dogs 28 days after the last breeding and for cats 16 days after the last breeding.  Ultrasound also often used as a non-invasive screening test for polycystic kidney disease in cats before retaining individuals for showing and breeding careers.

     Ultrasound-guided fine needle aspirate or ultrasound-guided tissue biopsy (liver biopsy shown in adjacent ultrasound image) offer less invasive methods of cytologic or histology tissue acquisition than laparotomy.  Sedation may or may not be required for aspirate samples, short term general anesthesia with analgesia is indicated for tissue biopsy.  Sampling of fluid from a distended renal pelvis, replacement of that fluid with sterile iodinated contrast and subsequent radiographic imaging is called a pyelogram.  An ultrasound-guided pyelogram may be considered to aid in differentiating partial from complete ureteral obstruction.  Although ultrasound can not be used to evaluate aerated lung tissue, it is used to evaluate and guide sampling of peripheral lung nodules and some other lung infiltrates.   

  Cardiac Ultrasound

     Echocardiography is a non-invasive way to evaluate heart anatomy and cardiac function.  Doppler imaging permits evaluation of both speed and directionality of blood flow and is especially useful for evaluation of valvular disease and congenital abnormalities.

Small Parts Ultrasound

     Thyroid/parathyroid ultrasound exams are preformed to characterize palpable masses including differentiation of vascular structures from cystic compartments and to guide tissue sampling.  Ultrasound is also helpful for the identification of non-palpable masses including parathyroid tumors, and in certain circumstances can be used to guide ethanol-ablation of some parathyroid masses as an alternative to surgery. 

     Ocular ultrasound can identify the lens (luxation, cataracts, etc) and the retrobulbar space (abscesses, neoplastic masses, ocular myositis) can be especially useful in older animals with benign nuclear sclerosis that obscures direct visualization of structures caudal to the lens.

     Ultrasound of the brain especially in young animals can be used to identify hydrocephalus. 

Musculoskeletal Ultrasound

     Ultrasound of the musculoskeletal system is used to assess soft tissue injuries that maynot be apparent on survey radiographs.  The most common areas examined in small animals include the Achillies tendon, iliopsoas muscle, shoulder (bicepts tendon, supraspinatus, infraspinatus, etc.) and soft-tissue or bony masses for targeted cytologic sampling.  For the equine patient musculoskeletal ultrasound is clinically used to assess tendons and ligaments of the distal limb, and joints, as well as their response to medical or surgical management.