Also called: Ultrasonography & Diabetes
Ultrasound is a safe and painless diagnostic test. It sends and receives high-frequency sound waves to create images of internal organs or tissues. Sound waves pass through the tissues of the area being examined. These sound waves are recorded and displayed on a computer screen or television-type monitor.
Ultrasound creates images of soft–tissue organs, such as the pancreas, thyroid gland, heart and kidneys, and of babies in the womb. Ultrasound can also detect blockages in the blood vessels.
The image created by an ultrasound is considered to be less clear than those from CAT (computed axial tomography) scans or MRI (magnetic resonance imaging). However, it is often used for a wide array of procedures because it is fast, noninvasive and relatively inexpensive.
Ultrasound is a common test used for many chronic diseases, including diabetes and other endocrine disorders, because it can often help in detecting complications. In extensive studies, no risks associated with normal use of diagnostic ultrasound have been documented.
Ultrasound, sometimes called ultrasonography or sonogram, uses high-frequency sound waves to create images of organs, blood vessels and tissues. The sound waves are too high for the human ear to hear, but they produce images that allow physicians to view internal structures and to assess blood flow.
Inspired by sonar technology, which uses sound waves to detect objects underwater, ultrasound can help diagnose and monitor a wide range of diseases and conditions, including diabetes, thyroid disease and other endocrine conditions. Ultrasound can be used alone or with other diagnostic procedures. Sonography is the medical term for the testing and recording of the ultrasound.
This versatile diagnostic tool is used for a wide variety of purposes, including assessing pregnancy and examining the chest, blood vessels and abdomen. Detailed images of the size and functioning of the heart can also be obtained. Ultrasound is also used frequently to guide fluid withdrawal from the chest, lungs or around the heart.
Ultrasound can be used to examine the internal structures of the abdomen (liver, pancreas, ureters, kidneys, etc.), and to detect gallstones and kidney stones. Other common uses for ultrasound include the detection of fluid, cysts, tumors or abscesses in the abdomen or liver, reduced blood flow due to clots or atherosclerosis in the legs, and aneurysms of the aorta.
Some of the most common ultrasound tests include:
- Abdominal ultrasound. Views the stomach, kidneys, pancreas, liver, gallbladder and other abdominal organs. May be used in diagnosis of diabetic conditions such as gastroparesis and fatty liver.
- Blood pressure measurement. Measures the blood flow through the arteries. May be used in diagnosis of diabetic complications such as high blood pressure.
- Breast ultrasound. Provides a closer look at a possible breast mass or tumor.
- Carotid duplex ultrasound. Assesses blood vessels in the neck. May be used in diagnosis of diabetic complications such as angiopathy and stroke risk.
- Echocardiogram and stress echocardiogram. Gives a look at the heart and its valves. May be used in diagnosis of diabetic heart conditions.
- Interventional ultrasound. Often used to guide a surgeon during a minimally invasive procedure, such as in inserting biopsy needles, draining infections or placing catheters for islet cell transplants.
- Musculoskeletal ultrasound. Used to determine the cause of shoulder pain, tendinitis, a tear in the rotator cuff or possible sports injuries.
- Pelvic ultrasound. Often used to find the cause of pelvic pain and may be useful in diagnosing sexual dysfunction.
- Pregnancy ultrasound. Checks the development of the fetus, including the baby’s heartbeat, size, location and (sometimes) sex.
- Prostate ultrasound. Provides a closer look at any nodules or other irregularities that may have been detected during a physical examination.
- Renal ultrasound. Views the kidneys and urinary tract. May be used in the diagnosis and monitoring of kidney disorders such as diabetic nephropathy.
- Thyroid ultrasound. Looks for possible abnormalities in the thyroid gland.
- Vascular ultrasound. Searches for blood clots and allows the physician to view how well the blood vessels are functioning. May be used in diagnosis of diabetic angiopathy.
In addition, higher-intensity therapeutic ultrasound is used in physical therapy and occupational therapy, as the thermal effects have been found to be helpful for treating musculoskeletal injuries, breaking down scar tissue and stretching tendons.
Other applications of ultrasound include:
- Healing wounds, such as diabetic ulcers.
- Breaking up kidney stones.
- Delivering medication through the skin (phonophoresis). Scientists are experimenting with phonophoresis to deliver insulin in an insulin patch.
- Helping surgeons dissolve blood clots in the brain.
- Treating cancer and benign tumors.
- Removing fat (lipoplasty).
Types and differences of ultrasound testing
There are several types of ultrasound testing, which uses high-frequency sound waves to create images of blood vessels, organs and tissues. One of the most common is Doppler ultrasound.
Based on the Doppler effect (the shift in wavelength as the distance of a source of sound changes), Doppler ultrasound is often used to measure the rate of blood flow through the arteries and the heart. When the object being measured is moving (e.g., blood flowing through the heart and arteries), the frequency of the echoes changes. There is a higher frequency when the object moves toward the probe and a lower frequency when it moves away from the probe. The sound waves hit the red blood cells as they move through arteries and veins and are reflected back to the transducer. This allows the technician to listen to and record the flow of blood through the body.
In addition, there are various techniques of ultrasound imaging, including:
- A-mode or amplitude modulation, which is recorded as a line showing the time needed to reach the organ and return to the transducer
- B-mode, which is brightness modulation
- Gray scale, which shows the texture of various organs in shades of white and gray
- Real-time imaging, which shows rapid multiple views of tissues in motion
Ultrasound testing is a common diagnostic tool for monitoring chronic conditions such as diabetes. Individuals with diabetes often require increased monitoring and screening because they are more likely to develop complications than nondiabetics. Uses for ultrasound with diabetes or other endocrine conditions include:
- Bladder. Ultrasound testing can be used to locate residual urine in the bladder, as well as the volume of urine in the bladder. Residual urine is a common diabetic condition.
- Bone mineral density (BMD). Some studies suggest that the nerve damage known as peripheral neuropathy may affect bone mineral density among patients with type 1 diabetes and possibly type 2 diabetes. BMD can be measured using ultrasound. However, it is generally recommended that a dual x-ray absorptiometry (DEXA) scan be used for monitoring BMD.
- Carotid atherosclerosis. Patients with diabetes are often at a higher risk of developing atherosclerosis, which hardens and narrows the arteries. Atherosclerosis in the carotid artery in the neck increases the risk of stroke.
- Chronic osteomyelitis. Diabetic individuals can develop osteomyelitis, a bacterial infection of the bone, especially in the foot.
- Diabetic mastopathy. This rare condition, found mostly in premenopausal women with type 1 diabetes, results in fibrous tissue or even hard lumps within one or both breasts. Diabetic mastopathy can be confirmed through mammogram or ultrasound.
- Fatty liver. This disorder causes fat to accumulate within liver cells. It is found with increased frequency among alcohol abusers, the obese and people with diabetes.
- Fetal ultrasound. When diabetic women become pregnant or nondiabetic women develop gestational diabetes during pregnancy, often the obstetrician will want to monitor the baby more intensively during the final trimester. Ultrasound can also be used to guide insulin treatment in women with mild gestational diabetes whose babies are at an increased risk of being born abnormally large (macrosomia).
- Gastroparesis. This disorder of the stomach is associated with long-standing cases of diabetes. A type of autonomic neuropathy, gastroparesis delays emptying of the stomach’s contents.
- Heart conditions. Researchers have found a type of pharmacological stress test (using medication rather than exercise to quicken heartbeat) called dobutamine stress echocardiography to be particularly effective in predicting heart attacks and cardiac death in diabetic women, and in ruling out cardiac ischemia (reduced blood flow to the heart).
- Renal ultrasonography. Ultrasound can assess kidney function and check for abnormalities. It is a useful test for patients with end-stage renal disease. Renal ultrasonography can also be used to determine the volume of urine in the bladder, a bladder dysfunction or changes in the shape of the bladder.
- Pancreas function. An ultrasound of the pancreas is used to help detect the size of the pancreas, to look for any abnormalities, including pancreatitis, or to guide the insertion of biopsy needles.
- Sexual dysfunction. Ultrasound has been used to assess blood flow in the genitals of diabetic women being treated for sexual difficulties.
- Thyroid imaging. An ultrasound scan of the neck region can help diagnose thyroid nodules, hyperthyroidism, thyroiditis or goiter, and may be used in evaluating parathyroid conditions in the adjacent parathyroid glands.
Before the ultrasound test
Preparations for an ultrasound test vary depending on the type of ultrasound. However, most ultrasound tests require little or no preparation. For ultrasounds being performed on internal organs, such as the gallbladder, patients may be asked to avoid eating or drinking for six to eight hours before the exam.
For a pregnancy ultrasound, expectant mothers are typically asked to drink up to six glasses of water prior to the test to fill the bladder. This is because the extra fluid in the bladder helps to move air-filled bowel loops away from the womb, creating a clearer view of the baby and womb during the test.
Smoking or other use of nicotine can interfere with ultrasound testing by causing blood vessels to constrict. A patient may be advised to avoid cigarettes, chewing tobacco and other nicotine products at least two hours before the test. Additionally, swallowing air can alter the results of some ultrasound testing as ultrasound waves do not pass through air. This is the reason that ultrasound testing is not commonly used on the stomach, small intestine or large intestine.
In preparation for an ultrasound, it may be helpful to ask a healthcare provider about:
- Restrictions on eating or drinking before the test
- Restrictions on use of nicotine products beforehand
- Wearing loose-fitting, comfortable clothing
- Avoiding soda or other carbonated drinks
- Taking medications prior to the test, including insulin
During and after the ultrasound test
Ultrasounds are usually outpatient procedures but are also used in hospitals as part of diagnostic patient care. Patients are usually advised to leave all jewelry and valuables at home.
In general, most ultrasounds follow a similar procedure:
- Depending on the area being tested, the patient may lie on a padded examining table during the test, which normally takes about 20 to 30 minutes. It may be necessary to change into a hospital gown depending on the area to be examined.
- A small amount of water-soluble gel, which acts as a conducer, is placed on the part of the body to be tested and/or directly on the transducer, the ultrasound machine’s device that emits sound waves. The gel does not harm the skin or stain clothing. The transducer should not be placed over an open or draining wound.
- The technician uses the transducer to send ultrasound waves through the body. The sound waves sent from the transducer bounce off the structures within the body.
- A computer deciphers the information to create the ultrasound images.
- The ultrasound images then appear on the monitor, and the moving pictures can be recorded on videotape.
Ultrasound testing is generally painless. Minor discomfort may be caused by the pressure of the transducer against the skin or, in the case of transrectal or transvaginal ultrasound such as for prostate or gynecological conditions, probe in a body cavity.
After the test, the gel is wiped off of the skin. The test is then evaluated by a radiologist and relayed to the patient’s primary healthcare provider. If the ultrasound shows a problem, additional diagnostic tests, such as MRI (magnetic resonance imaging), may be recommended.
Potential risks with ultrasound
In extensive studies, no risks associated with normal use of diagnostic ultrasound have been documented. Ultrasounds are considered to be safe, with no harmful side effects. Unlike x-rays, ultrasound involves no exposure to radiation. This test is a noninvasive procedure that is widely available, easy to use and painless.
Another type of ultrasound that is not the focus of this Patient Guide can have risks. Therapeutic ultrasound, a thermal technique used by physical therapists and other specially trained healthcare providers to treat conditions such as joint pain, can result in burns or other problems if improperly applied.
Questions for your doctor regarding ultrasound
Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about ultrasound:
- Do I need ultrasound tests to monitor kidney function, cardiovascular disease or other complications of diabetes? If so, how often?
- How often will I need ultrasound testing?
- When and where will I have this testing?
- Do I need to do anything to prepare?
- What can I expect during ultrasound? Will I feel anything?
- Do my ultrasound results show the need for any additional testing or treatment?
- Do my test results show the need to begin or change my treatment? If so, what are my options?
- If I’m pregnant, does having diabetes increase the frequency of my need for fetal ultrasounds?
- Can therapeutic ultrasound help my diabetic neuropathy, ulcer, joint pain or other conditions? If so, where should I go for therapeutic ultrasound, and how often?
- Does ultrasound have any risks for me?