What Is Veterinary Diagnostic Imaging?
Veterinary diagnostic imaging includes radiographs (x-rays), ultrasound, MRIs and CT scans, all of which are used as diagnostic tools to collect information about your dog's health. The vast majority of imaging is non-invasive and completely painless. However, some imaging may require sedation or anesthesia because the dog must be kept still so that adequate images can be produced. Veterinarians use these images to inform their medical or surgical plan for your pet.
When Is Veterinary Diagnostic Imaging Necessary?
After your veterinarian has examined your dog, he or she may want to collect more information before making a diagnosis. X-rays are usually the first line of imaging. When x-rays inconclusive, the next step may be to take ultrasound images to give your veterinarian a closer look at a particular area of the patient's body.
For instance, if your dog is vomiting or feeling ill, your veterinarian may take an x-ray to look for possible causes such as intestinal obstruction. In some cases it may be prudent to supplement x-ray images with an abdominal ultrasound. The ultrasound gives a more detailed picture of the affected area and therefore improves the doctor's confidence before settling on a treatment plan or moving forward with surgery. When x-rays and ultrasound are insufficient for arriving at a definitive diagnosis, your veterinarian may need to collect other information when solving the puzzle of your dog's ailment.
Our veterinarians use four types of veterinary diagnostic imaging in the diagnosis of a patient's condition:
- CT scan
More information on each of these types of radiography is provided below.
Dog x-rays have been used in the medical community for many decades. Dog x-rays are by far the most regularly used form of diagnostic imaging in the veterinary industry because they are cost-effective (comparatively speaking) and they are essential for assessing the state of skeletal structure and bone composition, large body cavities, and the presence of foreign objects. Dog x-rays are completely painless, but some dogs may benefit from sedation to reduce anxiety and stress.
Dog x-rays usually proceed as follows:
- The patient is placed on the x-ray table.
- A technician positions the x-ray machine so that the x-ray beam targets only the area of interest.
- Modern x-ray machines emit low levels of radiation and are perfectly safe for your dog when used occasionally.
- Because dog x-rays are static images, they usually takes less time than other procedures such as MRI.
Dog x-rays have traditionally been captured on actual film and still can be when necessary. Our x-ray images, however, are digital, which enables us to store them on a secure server for access at any time and for easy consultation with specialists.
A dog ultrasound is the second most common type of diagnostic imaging tool veterinarians use to diagnose a dog's medical condition. Ultrasound uses sound waves to examine and photograph internal tissues in real-time. An ultrasound enables a veterinarian to examine organs from more angles than those afforded by x-rays and assess their function and the flow of blood.
A dog ultrasound procedure usually proceeds as follows:
- A dog ultrasound technician gently presses to the patient's body a small probe body that emits sound waves.
- The technician directs waves to various parts of the dog's abdomen by manually shifting the probe.
- The sound beam changes velocity while passing through body tissues of varying density, which creates echoes.
- Our ultrasound equipment converts these echoes into electrical impulses that are then transformed into a digital image representing the appearance of the internal tissues.
- Those images can be viewed in real-time by a veterinarian as well as stored for future review.
In modern scanning systems like those that GoodVets has on-site and uses on our canine patients, the sound beam sweeps through the body many times per second. This produces a dynamic, real-time image that changes as the dog ultrasound device moves across the patient's body. We can use the results of an ultrasound to determine what ails your dog and to formulate the most effective treatment plan.
Symptoms that commonly lead a veterinary to use ultrasound imaging include vomiting, weight loss, kidney impairment or blockage, and heart disease.
Magnetic resonance imaging, or MRI, is the newest form of diagnostic imaging used for both human and veterinary medicine. Dog MRI equipment generates a powerful magnetic field used to create highly detailed anatomic images. A dog MRI is regarded as completely safe.
A dog MRI procedure usually proceeds as follows:
- Dogs must be sedated for this procedure because they cannot be restrained by humans and must remain still during the procedure.
- The patient is placed in a tubular electromagnetic chamber.
- The dog's body is continuously pulsed with radio waves for a period of time, usually 10-20 minutes.
- The pulsing causes the dog's body tissues to emit radiofrequency waves that are detected by the MRI equipment. Many repetitions of these pulses and subsequent emissions are required in order to generate adequate digital feedback for the machine to interpret.
- The feedback is then converted into images that can be displayed on a screen and saved for future review.
A dog MRI is not used as regularly as an x-ray or ultrasound because the equipment is very expensive, very large, and requires specially trained technicians to operate. However, GoodVets offers comprehensive dog MRI services because we believe that facilitating complete canine care means having all the tools and training necessary to do so.
CT Scans for Dogs
CT scans, also known as cat scans, are computer-enhanced x-ray procedures most often used to evaluate complex parts of the body, such as the head, chest, some joints, and various internal organs. CT scans show different levels of tissue density and produce more detailed images than x-rays. Unlike MRIs, CT scans for dogs do not use magnetic field waves so they cannot compare changes in fluid levels due to inflammation or bleeding. Therefore, CT scans for dogs are used in situations where an MRI is considered unnecessary but a traditional x-ray is inconclusive or insufficient.
CT scans for dogs usually proceed as follows:
- The dog must be sedated for this procedure because they cannot be restrained by humans and must remain still during the procedure.
- The patient is placed on a motorized bed inside the CT scanner, a machine that takes a series of x-rays from various angles.
- When one series, or scan, is completed, the bed moves forward and another scan is taken.
- A computer uses these scans to create cross-sectional images of the body part under investigation and then displays the images on a monitor. (An x-ray dye may be injected intravenously to make it easier to see abnormalities.)
- By sequentially scanning the area of interest, an organ or other structure can be imaged without penetrating the body or disrupting neighboring structures.
CT scans for dogs are most often used by our veterinarians to detect structural changes deep within a dog's body, including:
- Deep abscesses
- Foreign bodies
As with MRI equipment, CT scanning equipment is very expensive, large and requires trained technicians to operate. In our mission to offer your dog all the advantages of advanced diagnostics, we provide CT scans for dogs at our veterinary hospitals.
How Canine Radiographs Influence Veterinary Recommendations
The goal of canine radiographs is to arrive at a diagnosis or without performing invasive tests or procedures. For example, an x-ray might show some soft tissue swelling in the knee, and the addition of an MRI might reveal the specific tendon or ligament tear that is causing a dog to limp. The enhanced accuracy these tools grant our veterinarians greatly improves their ability to diagnose and treat your dog.
If you are concerned that your dog might be injured or experiencing internal problems, or if you'd like to discuss how canine radiographs can benefit your dog, please contact us to schedule an appointment with one of our veterinarians today.