Continuous advances in ultrasound technology have provided veterinary practitioners with a safe and cost-effective diagnostic tool that can be applied to a wide range of clinical scenarios. The range of clinical applications for ultrasound is very broad, but we can begin by thinking about some of the uses of ultrasound.
Urinary Tract and Many Other Body Systems
When clinical presentation, clinical examination, and initial workup suggest a problem in a specific area, ultrasound can provide a means of quickly assessing the anatomy involved. Some common system-specific ultrasound examinations are:
1. Gastrointestinal Tract - foreign bodies, inflammatory bowel disease, neoplastic changes
2. Hepatobiliary System - neoplastic changes, diffuse and focal liver disease, cholecystitis, and cholelithiasis
3. Spleen - splenic torsion, neoplasia, parenchymal changes
4. Urinary Tract - urolithiasis, cystitis, neoplastic changes
5. Vascular System - thromboembolism, tumors, quantification of blood flow to organs, and pathological changes
Urinary bladder (UB) contains multiple stones (red arrows)
Limbs or Musculoskeletal System
Ultrasound can provide detailed images of soft tissue structures and complement other techniques such as studying musculoskeletal conditions.
1. Identify pathology and track healing of tendons, ligaments, and muscles
2. Inspect the surface of bony structures for changes
3. Evaluate joint structures such as cartilage, collateral ligaments, and menisci
4. Guide treatment and sampling
In emergency situations, ultrasound can be used to quickly obtain information with less risk of harming the patient than other imaging modalities. For small animal patients, ultrasound can be used quickly and accurately to:
1. Evaluate body cavities for the presence of free fluid or hemorrhage
2. Evaluate the chest to help detect pneumothorax and pericardial effusion
3. Semi-quantify current changes, and because ultrasound is easily repeatable, it allows for continuous monitoring
For equine patients, ultrasound can be used for local abdominal assessment:
1. Evaluate the position and motility of the intestines
2. Evaluate intestinal contents, intestinal wall thickness, and intestinal distension
3. Identify free fluid
Ultrasound can be used to quickly identify fluid surrounding the bladder and small intestine in this patient
Reproduction in Equine Patients
The portability and image quality of modern ultrasound systems make them ideal for reproductive management in horses. Ultrasound improves reproductive efficiency and is an important component of artificial insemination (AI) and embryo transfer programs.
1. Reproduction assessment prior to breeding
2. Monitoring ovarian activity can help guide the timing of effective breeding and AI
3. Investigating behavioral and hormonal issues
4. Early detection of pregnancy and management of twin pregnancies
55mm diameter follicles
Multiple abdomens
The versatility and additional diagnostic tools offered by ultrasound have made ultrasound examinations part of the baseline medical evaluation for many species. A structured and thorough evaluation of the abdomen can provide clinicians with a wealth of information and can be applied to many situations, including the following investigations:
1. Palpable abdominal masses
2. Abdominal pain
3. Lethargy and weight loss
4. Vomiting and diarrhea
5. Suspected endocrine disease
6. Changes detected in hematology and biochemistry
7. Polyuria and polydipsia
Left adrenal gland
Strange sounds or murmurs to investigate the heart
Echocardiography allows clinicians to obtain detailed, real-time images of the heart and surrounding structures. The use of phased array transducers capable of continuous wave Doppler ultrasound allows for accurate measurement of higher velocity blood flow.
1. Evaluate pericardial structures and identify pericardial effusions
2. Examine the structure and function of cardiac chambers and valvular structures
3. Quantify chamber size and record blood flow patterns and velocities by Doppler ultrasound
4. Determine the source of heart murmurs and the location of cardiac abnormalities
Right parasternal long axis: left ventricle, left atrium, and mitral valve
Obstetrics
As a norm in human medicine, ultrasound is an excellent tool for detecting and monitoring pregnancy in all species.
1. Early detection of pregnancy to allow for appropriate management and advance planning
2. Identify abnormalities and changes to allow for early intervention
3. Quantification of gestational age and number of fetuses
4. Monitor fetal viability throughout pregnancy
5. Can fetal sexing in certain species be facilitated