Sonography or ultrasound is the use of sound waves to produce an image or photograph of an organ or tissue. The ultrasound has different velocities in tissues, which differ in density and elasticity from others. This property permits the use of ultrasound in outlining the shape of various tissues and organs in the body.
An abdominal ultrasound allows for an image to be viewed through or across the abdomen. During an abdominal ultrasound, a wand (transducer) with conducting jelly is place on top of the abdomen and gently moved around to image the abdomen.
Here is a list of some of the most common canine conditions where abdominal ultrasound is used as a diagnostic tool.
Abdominal Ultrasound to Diagnose Dog Adrenal Conditions
An abdominal ultrasound isn't required to make a diagnosis of Cushing's disease, but it can help to complete the clinical picture. Cushings disease, or hyperadrenocorticism, is when a dog's adrenal glands are overactive and producing too much cortisol. It can happen due to an overactive pituitary gland stimulating increased adrenal activity, or due to a tumor on one adrenal gland. The main diagnostic tests for Cushings are blood tests, but these tests can have false positive and false negative results and making a diagnosis is not always straightforward.
When tests are inconclusive, an ultrasound can help to visualize the adrenal glands. The adrenal glands are small and can be difficult to find, so it is important to use an experienced ultrasonagrapher. If both glands are enlarged, it is indicative of pituitary-dependent Cushing's. If one is enlarged and the other small, it indicates an adrenal tumor. If both appear normal, Cushing's disease is less likely. Because the excess cortisol in the body can negatively impact the liver, the ultrasound exam also allows us to visualize the liver to check for potential abnormalities.
An ultrasound is fairly quick and noninvasive. However, if done by an experienced examiner it can be expensive. If blood tests for Cushings are conclusive, it may not be necessary in every case. In other cases it can be a key component in the diagnostic workup.
Abdominal Ultrasound to Diagnose Dog Stomach and Intestinal Problems
The most limiting factor for ultrasound examination in any case is presence of gas inside or outside of the organ we wish to examine. Gas bubbles reflect 100% of ultrasounds, so there aren't any left to be reflected by underlying structures and thus give us information about their shape, size, composition etc. When dog is bloated, stomach is filled with air and other gases, which makes use of ultrasound in diagnostics pretty much impossible, and unnecessary since x-rays are very reliable diagnostic under such conditions as they are unaffected by the presence of air in organs.
Symptoms of hemorrhagic gastroenteritis can also be present in some other conditions, like pancreatitis, hypoadrenocorticism, foreign bodies in the bowels, ileus etc. On top of that HGE is basically a diagnosis of exclusion, meaning we have to look for, and exclude other possible differentials before declaring the dog has HGE, since we can't test for it directly. Due to these facts, CBC, BCP, ultrasound and x-rays are necessary part of diagnostic process.
IBD is diagnosed with biopsies, but an abdominal ultrasound is a great diagnostic tool prior to biopsies that may identify changes consistent with IBD. The Abdominal ultrasound is non-invasive and low-maintenance for owners.
An abdominal ultrasound is the only way to achieve a definitive diagnosis of pancreatitis (in combination with blood tests). This diagnostic is non-invasive and dogs tolerate being ultrasounded very well. The amount of information this test can provide makes it more than worth the cost.
Ultrasound is a great way to evaluate the soft tissue in the abdomen. It's possible to screen the structure/walls of the stomach and GI system. The technique is non invasive and can be done on most patients without sedation. In many cases it may be a halfway point to surgery, but can give a lot of information prior to making the decision to do anesthesia or surgery.
An ultrasound for splenic torsion would allow identification of the abnormal spleen position as well as vascular compromise from the twist. Ultrasound is not painful for dogs and can be done on most without any sedation. This is a great way to gain insight when there is a suspected need for surgery but some doubt.
Abdominal Ultrasound to Diagnose Dog Liver Conditions
Ultrasound examination can be very useful in cases of liver cancer, or any liver disease for that matter. Another important use of US in the case of liver disease is ultrasound guided fine needle aspiration for sample hepatic tissue or bile for cytology or microbiology. In cases of hepatic tumors it's very useful for determining location, size and relation of solitary/nodular tumors with surrounding tissues, all of which are valuable information for surgeon to have when planing an operation. In cases of diffuse tumors, while indicative in some cases, research suggest that different diseases can't be reliably differentiated based on ultrasound exams, although most prevalent multi-focal hepatic lesions were hemangiosarcoma and hepatocellular carcinoma (>60%). Ultrasound with Doppler perfusion index be used to check for signs of metastases on surrounding tissues and lymph nodes , while contrast enhanced US can help differentiate between benign and malign lesions.
An abdominal ultrasound allows for a 3D look at the liver (vs. x-rays that are 2D). This will show any nodules/tumors/structural (size, shape) changes within the liver that may indicate disease. An ultrasound is non-invasive and just requires clipping any fur on the belly. Most dogs will lay still for this procedure with no problems.
Nodular hyperplasia is a benign condition which doesn't cause any symptoms nor changes in CBC or blood chemistry, it's mostly an incidental finding on ultrasound or laparotomy which are performed because of some other problem. Despite the fact that nodular hyperplasia is a common finding (15-60% of older dogs have it), it should never be glanced over, especially when found on ultrasound, since it can't be differentiated from other liver tumors based on macro appearance alone.
Benign hepatic tumors - hepatocellular adeomas, are usually subclinical, and cause symptoms only if they rupture and hemorrhage. In most cases they are accidental findings and don't require treatment, unless they are so large that they cause problems due to the pressure they exert on liver, blood vessels and other adjunct organs.
Abdominal Ultrasound to Diagnose Dog Reproductive Conditions
Uterine inertia is a common complication during labor, especially when there was already some problem with giving birth to one of the pups, or labor simply lasts too long. Ultrasound is the best tool to check on the pups, though it has it's downsides. Biggest value of the ultrasound examination is that it can tell us if pups are still alive, because we can detect heartbeat with it, which is impossible with xray. Downside of the ultrasound in this cases is the biggest downside of ultrasound in general, if there is gas, we can't see anything behind it, and gas collection is not uncommon in both uterus and intestines during complicated births. In these cases x-rays are needed to confirm or disconfirm presence of pups in uterus.
A pyometra typically has a "classic" presentation and can be identified with a thorough history, physical examination and abdominal x-rays. However, in some cases, ultrasound is the next best step to see if there is any confirmation of a pyo. Often times x-ray can be utilized but ultrasound is usually faster and more efficient when looking for fluid in the uterus. Pyometra is a life threatening condition so quick diagnosis and treatment are the key to a successful outcome.
To confirm ovarian tumors with an abdominal ultrasound, the ultrasonographer finds the ovaries and looks to see if they are of abnormal shape and size. Chances for "false positives" are quite low.
Ultrasound is a good way to image the prostate. If it is found to be a solid mass then an ultrasound guided biopsy can be helpful. The scan is non-invasive and can be done on most patients without sedation, though a biopsy would require sedation.
Ultrasound is the quickest way to get to the bottom of what is going on with the prostate. It can determine if there is a mass, an abscess or a cyst. This can generally be done on patients awake without pain. It is a very useful way to gain data quickly and non-invasive.
Since a cryptorchid dog should be neutered most of the time the issue is deal with by surgical exploration. If a dog was adopted as an adult and has no scrotal testicles, but is showing signs of testosterone it may be a good idea to start with an ultrasound to see if there is a retained testicle.
This is a non-invasive procedure that can be done on most pets without sedation. It does not cause discomfort.
Uterine tumors rarely cause clinical signs, and are usually incidental findings when the dog is brought to the vet for some other reason. If a tumor is suspected, ultrasound is by far the best imaging technique to look for it and determine if it's really a uterine tumor or if some other organ nearby is affected. Ultrasound can also help determine the exact location and size of the tumor, which makes planing for surgery a lot easier.
Uterine infections are common. Often time fluid in the uterus can be diagnosed off x-ray but if there are questions regarding early pregnancy ultrasound can distinguish between them. Ultrasound is noninvasive and relatively easy to do in the hands of a trained veterinarian. This can be a really simple way to evaluate a dog prior to taking her to surgery.
Abdominal Ultrasound To Diagnose Dog Urinary Conditions
Using abdominal ultrasound we can visualize kidneys, urethers (in some cases) and urinary bladder, and check for changes in size, shape, urinary stones, obstruction, and certain specific sings. Another very important use of US in these cases is taking assisted fine needle biopsy, which is essential for diagnosing kidney lymphoma.
Abdominal ultrasound is the best way to visualize kidneys, check for changes in size and shape of the kidneys, dilation kidney pelvis (part where urine collects and flows down to the ureters), dilation of ureters in cases of obstruction, as well as kidney stones and other material that might be present. Percutanous pyelocentesis (draining of puss and debris from kidney pelvis, by sticking needle through the skin) is done with the aid of ultrasound when needed. This technique can also be reversed and used to infuse kidneys with antiseptic solutions to help fight the infection.
A ureteral stone may be difficult to find, but if there is a blockage ultrasound can assess for dilation of the renal pelvis(the urine collection are in the kidney). The health of the bladder can also be evaluated. Additionally fluid free in the abdominal cavity can be identified if there is a rupture in the urinary system from blockage. Abdominal ultrasound is non-invasive and relatively easy to perform in most patients without sedation. It is an excellent diagnostic tool.
Ultrasound is an excellent imaging tool for the urinary and reproductive system. The thickness of the bladder wall can be evaluated as well as the location of a tumor. This is very helpful because the location plays a huge roll in the how useful surgery would be. Ultrasound is generally easy to do on most patients without sedation. It is non-invasive and helps to make decisions moving forward in the treatment of bladder cancer. This can be done in many clinics.
Urinary tract obstruction is an umbrella term which covers all conditions which may lead to problems with the outflow of urine. These conditions range from urinary stones, urinary bladder inflammation/infection, various kinds of bladder tumors, trauma, prostate hyperplasia, abscess and cancer, abdominal tumors, neurological conditions... While ultrasound can't diagnose all of these conditions, it's pretty much the best tool for recognizing/suspecting wast majority of them, particularly bladder and prostate conditions.