Overview of Sonography Abdominal Vascular Assessment, Protocols, and Interpretation
There are several diseases that can affect the blood vessels in your belly. These include conditions like aneurysms (bulges in the blood vessel), dissections (separation of the layers within a blood vessel), hardening of the arteries (also known as atherosclerosis), and conditions that limit blood flow. One such illness is abdominal aortic aneurysm (AAA), a serious condition that can be life-threatening. It affects about 2% of adults over the age of 50.
AAA can be detected using ultrasound, a safe and effective method that’s well-suited to spot these types of problems. Ultrasound uses sound waves to create pictures of the inside of your body. It is very good at finding AAAs due to its accuracy.
However, while ultrasound is great for detecting AAAs, it’s not as effective for evaluating other blood vessel issues. These include diagnosing if an aneurysm has burst, spotting aortic dissection (a serious condition involving your largest blood vessel), abdominal aortic stenosis (narrowing of the aorta), problems with major branch of blood vessels, and conditions affecting your inferior vena cava (a large vein that carries blood from your lower body to your heart).
There are no set rules for how doctors should use ultrasound for images of the blood vessels in your belly. The guidelines suggested in the original article are meant to help healthcare providers evaluate the aorta (the main blood vessel in your body), the inferior vena cava, arteries in the middle of your belly, and the iliac arteries (which carry blood to your lower body) for any signs of disease.
Anatomy and Physiology of Sonography Abdominal Vascular Assessment, Protocols, and Interpretation
The abdominal aorta is the main blood vessel that transports oxygen-rich blood from our heart to our lower body and organs in the abdomen. Its journey starts just below the large muscle that helps us breathe – the diaphragm, and ends where it splits into two common iliac arteries.
On the other hand, the Inferior Vena Cava (IVC) is a significant blood vessel responsible for carrying oxygen-poor blood from the lower part of the body and certain organs in the abdomen and pelvis back up to the heart. The IVC is located to the right of and travels parallel to the aorta. It starts where the two iliac veins (large blood vessels that carry blood from the lower body) join and ends at the right atrium, one of the four chambers of the heart.
Why do People Need Sonography Abdominal Vascular Assessment, Protocols, and Interpretation
If a medical professional needs to confirm that you have an abdominal aortic aneurysm, which is a swelling in the major blood vessel that runs from your heart down through your chest and tummy, they will conduct a screening. This is also done when there’s a suspicion or chance that you may have an iliac aneurysm. An iliac aneurysm occurs when the iliac arteries, located in your pelvis, enlarge or swell.
In case you are experiencing low blood pressure, a condition also known as hypotension, tests might be performed as well. Similarly, checks will be made if you can’t feel a pulse in your lower limbs, which can sometimes indicate a serious issue.
Finally, if there’s a suspicion that you have mesenteric ischemia, a condition caused by poor blood supply to your intestines, a test will be done. This is important because the condition can lead to severe abdominal pain and potentially harm your digestive system.
When a Person Should Avoid Sonography Abdominal Vascular Assessment, Protocols, and Interpretation
There are no specific reasons that would completely prevent a person from having this procedure.
Equipment used for Sonography Abdominal Vascular Assessment, Protocols, and Interpretation
Choosing the Right Equipment
The tools used to create body images, known as transducers, come in different frequencies, generally between 1.0 to 5.0 MHz. They work well on most adult patients. However, their settings may need to be adjusted depending on the patient’s physical size and shape.
Who is needed to perform Sonography Abdominal Vascular Assessment, Protocols, and Interpretation?
This procedure can be done by specialized healthcare professionals who are trained in using ultrasound for diagnosis, known as registered diagnostic medical sonographers (RDMS). Alternatively, it can also be done by doctors who have received special training in using ultrasound.
Preparing for Sonography Abdominal Vascular Assessment, Protocols, and Interpretation
The patient should not eat anything for 4 to 6 hours before the imaging test. This is known as being in a fasting state. During the test, the patient is typically asked to lie flat on their back, which is called the supine position. If it’s hard for the technician to get good pictures this way, the patient might be asked to move to their right or left side, known as the right or left lateral decubitus position. This test is often done in a dark room to better see the images on the screen.
How is Sonography Abdominal Vascular Assessment, Protocols, and Interpretation performed
When it comes to imaging your body, detail matters. The doctor wants to get a clear picture of your abdominal aorta, which is the largest artery in your abdomen. They do this by setting the imaging device so they can see the vertebrae behind your aorta. They then record images from two angles: a “short axis” and a “long axis”. Both of these show the full length of your abdominal aorta from the diaphragm to the point where the common iliac vessels branch off. The doctor will measure the widest part of the aorta in both views.
If an aneurysm, a bulging or ballooning part in an artery, is found, the doctor will note its location in relation to the renal arteries, which are the ones supplying your kidneys. They will also measure the distance between the renal arteries and the aneurysm, and the size of the aneurysm. The sizes of your right and left common iliac arteries will be measured as well.
Any abnormal findings like blood clots or tissue flaps will be noted. If there is an endograft, which is a tube placed in the artery to support it, the points of attachment will be recorded. They will also check blood flow within the graft and the aneurysmal sac by applying colors and spectral doppler.
If needed, the doctor may also record the peak systolic velocities, which is the highest speed of your blood flow, in your celiac artery, superior mesenteric artery, and inferior mesenteric artery. These are important arteries in your abdomen.
The doctor may also want to view a vein called the inferior vena cava. They will measure its diameter a few centimeters from its joining point with the right atrium of your heart. This will be done during both your inhale and exhale.
However, there might be challenges like bowel gas which can block the view. The doctor can apply steady pressure or ask you to lie on your side to move the gas. If images from the front of your abdomen are not clear enough, they may take a view from your side.
To reduce the risk of missing an aneurysm or incorrectly measuring its size, the doctor will measure your aorta in both short and long views. They will be cautious to avoid the ‘cylinder tangent effect’ and ‘oblique angle overestimation’. The ‘cylinder tangent effect’ means underestimating the size due to measuring beside the center of a cylindrical structure, while ‘oblique angle overestimation’ means measuring at a slanted angle can give a larger size.
If video clips can’t be stored, still images will be taken at three different levels: near the celiac trunk (the main artery of your abdominal organs), the superior mesenteric artery (the main artery supplying your intestines) and just before the iliac bifurcation (the splitting point of your iliac arteries).
Possible Complications of Sonography Abdominal Vascular Assessment, Protocols, and Interpretation
This procedure doesn’t come with any associated complications or problems.
What Else Should I Know About Sonography Abdominal Vascular Assessment, Protocols, and Interpretation?
The abdominal aorta, the largest artery in your body, is often evaluated using ultrasound technology. While the standard diameter for this artery is about 2 centimeters, some discrepancies can occur. If the artery’s diameter is over 3 centimeters, this might indicate the presence of an aneurysm – or a bubble-like swelling – in the artery.
As a general rule, the larger an aneurysm is, the more likely it is to rupture. There are two types of aneurysms: fusiform and saccular. Fusiform aneurysms affect the entire diameter of your artery, while saccular ones only affect a small part.
The inside of your abdominal aorta usually appears echo-free or dark in ultrasound. If it appears otherwise, it might mean that there’s a clot or other abnormal formation. A distinct line inside the vessel might indicate a condition called aortic dissection, which is a serious and potentially fatal rupture of the aorta.
Sometimes, technicians might confuse the sidewall of a twisted aorta for an intravascular clot or a seal inside the artery. This is why it’s so important to thoroughly and accurately evaluate the aorta from different angles.
After you’ve received an endovascular graft – a treatment to repair a weakened part of your artery -, doctors will monitor the graft using ultrasounds. They’ll check for fluid build-up and unwanted blood flow outside the graft, which can lead to aneurysm expansion.
Five types of leaks, called endoleaks, can occur at the graft site. These leaks vary depending on their location and cause – from leaks developing along the graft attachment sites to leaks resulting from the graft’s material.
Ultrasounds that use color to display blood flow, or contrast-enhanced ultrasonography (CEUS), are becoming more popular due to their higher sensitivity and better results than conventional ultrasounds.
Other arteries located near the aorta, like the iliac and mesenteric arteries, can also have aneurysms, clots, or vascular seals. The shape of these abnormalities is usually similar to those found in the aorta.
Lastly, the inferior vena cava (IVC), a large vein that carries blood from your lower body to your heart, should appear echo-free as well. If there are hypoechoic or partially echo-free structures, those might indicate the presence of thrombi or IVC filters, which are devices that prevent blood clots from reaching your lungs. The IVC’s diameter can help estimate certain conditions in severely ill patients, but it isn’t a definitive measure of a patient’s fluid status or fluid responsiveness.
