Beginning in the early 1980's, ultrasound scanning
has been used to diagnose many disease processes in small animals.
It is now considered to be an essential service in all veterinary
teaching hospitals and large referral centers and many general small
animal practices. The reason for this is simple, ultrasound offers a
non-invasive, non-painful method for the diagnosis and staging of many
diseases. Ultrasound is the
best modality to evaluate fluid filled and soft tissue organs. Because ultrasound will not penetrate through air, ultrasound
cannot be used to evaluate abnormalities if they are surrounded by gas.
Why
Ultrasound?
Put simply, ultrasound allows us to visualize the internal architecture
of many organs. Radiographically inapparent internal abnormalities such as
nodules, masses, cysts and abscesses cannot only be seen, but can also
be counted and measured. Although
the ultrasound examination alone is in many cases non-specific for a
particular disease, in conjunction with the animal's age, sex, breed,
history, physical exam, radiographic findings and labwork, as well as
ultrasound guided fine needle aspirates or true-cut biopsies, the
specificity for disease can be high.
Many organs that are difficult to see on plain film radiographs
(prostate) can be easily seen with ultrasound.
Real-time echocardiography (ultrasound examination of the heart)
also allows us to see the heart in motion.
From these images, measurements of cardiac contractility, areas
of abnormal wall motion, chamber dilatation and wall thickening are made
and compared to normal values. The
typical ultrasound examination requires no tranquilization or anesthesia
and is easily performed on awake animals.
Prior fasting or water withholding is NOT required.
The only patient preparation necessary is clipping of the hair
overlying the area to be scanned (the ultrasound will not penetrate
through hair) and placing coupling gel on the skin surface just prior to
the exam process. The
entire scanning process takes 30-40 minutes.
Images are acquired on the monitor of the ultrasound machine as
well as on film for later viewing.
What Can
I See With Ultrasound?
Ultrasound is best at diagnosing abnormalities that
are discrete. An example of
this type of lesion would include a mass (tumor) in the liver.
Once found, the mass can be accurately measured for later
comparison. If the mass is
found in an organ that is not required (such as the spleen), careful
examination of the other organs (such as the liver) for the presence of
metastatic disease (tumor spread) is needed prior to surgical removal of
the "expendable" organ. Ultrasound
is used to diagnose a variety of both benign and malignant diseases such
as the presence of stones within the urinary bladder, kidneys or gall
bladder, infection of the gall bladder, urinary bladder, prostate or
kidneys, the presence of enlarged lymph nodes, abnormal blood vessels,
or free fluid within the abdomen.
It is especially good in diagnosing disease of the pancreas (pancreatitis),
adrenal abnormalities, urinary bladder wall tumors, uterine infections (pyometra)
and masses that are located behind the eyeball (retrobulbar masses).
Ultrasound can often differentiate benign prostatic enlargement
from prostatic cancer. In
animals with a history of vomiting, ultrasound can be used to evaluate
if the problem is within the liver, gall bladder or pancreas.
It can often diagnose problems that are associated with the
stomach or small intestinal wall, or see an intestinal foreign body,
thus preventing a labor intensive and costly upper GI barium study.
The diagnosis of pregnancy and fetal viability (heartbeats) are
commonly seen by 21 days post-conception with ultrasound, which is much
earlier than can be done with x-rays (42 days).
In the heart, ultrasound is at it's best, as the heart is fluid
filled organ. Abnormalities
such as a diseased heart muscle (hypertrophic and dilatory
cardiomyopathy), fluid around the heart (pericardial effusion), and
congenital abnormalities can be diagnosed and the severity can be
assessed. Heartbase tumors,
which are rarely seen on radiographs, are easily visualized with
ultrasonography. Ultrasound
can easily differentiate fluid within the cranial mediastinum from a
mass. Recently, ultrasound
has been used to evaluate tendon abnormalities of the shoulder and knee
(stifle). Ultrasound often
diagnosis problems earlier than would otherwise be possible.
This often affords an earlier diagnosis for better chance of
successful treatment.
Why am I
Being Referred?
Although ultrasound capability is found in many
general small animal clinics, many cases require the animal to be
scanned (or re-scanned) by a board certified specialist with training in
ultrasound. Many diseases
can be diagnosed using ultrasound by your family veterinarian.
Occasionally, however, there are questionable findings or the
diagnosis is not "clear-cut" and a second opinion is in the
best interest of the animal patient.
This process is similar to human medicine where, for example, an
internist or family practitioner will perform the initial ultrasound
examination, but for a number of reasons may then refer you to a
radiologist who is specifically trained in ultrasound, to get a second
opinion. Your veterinarian
must initiate the referral to Gulf Coast Veterinary Diagnostic Imaging
and they will send any pertinent lab data or x-rays to the radiologist.
What is
a Veterinary Radiologist?
Veterinary radiologists who are
board
certified by the American
College of Veterinary Radiology (ACVR) are uniquely qualified to
render first or second opinions on ultrasound examinations.
These veterinarians have completed a formal 3-4 year residency in
diagnostic imaging and have had intense formal training and practical
experience in ultrasound of both small and large animal species.
There are approximately 210 board certified veterinary
radiologists in the world, with most practicing in the United States.
Certification by the ACVR assures competency in ultrasound
diagnosis and ultrasound guided tissue sampling.
What Can
I Expect at the Referral Hospital?
At the time of your appointment, the radiologist will
meet with you and your pet and explain the procedure to you.
Most examinations will take 1-1.5 hours.
If biopsies or aspirates are needed, the radiologist will inform
you prior to obtaining them. If
other procedures are needed before, during or after the ultrasound
examination, these will be discussed with you.
Following the examination, the radiologist will discuss the
findings with you in detail, as well as discuss the "next
step". If an
ultrasound guided biopsy\aspirate was obtained, the results will be
available within 2-3 days and the results will be faxed to your family
veterinarian. Questions
concerning the results can be addressed to both the radiologist and your
veterinarian. In all cases,
you and your pet will be instructed to return to your regular
veterinarian for further treatment or surgery.
If specialized treatment is required and your veterinarian
wishes, your pet can be transferred to the appropriate service within
our hospital.
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