Ultrasound (Sonography)

Ultrasound imaging, also called ultrasound scanning or sonography, is a method of obtaining images from inside the human body through the use of high frequency sound waves. The reflected sound wave echoes are recorded and displayed as a real-time visual image. No ionizing radiation (x-ray) is involved in ultrasound imaging. Obstetric ultrasound refers to the specialized use of sound waves to visualize and thus determine the condition of a pregnant woman and her embryo or fetus.

Ultrasound is a useful way of examining many of the body's internal organs, including the heart, liver, gallbladder, spleen, pancreas, kidneys, and bladder. Because ultrasound images are captured in real-time, they can show movement of internal tissues and organs, and enable physicians to see blood flow and heart valve functions. This can help to diagnose a variety of heart conditions and to assess damage after a heart attack or other illness.

Millions of expectant parents have seen the first "picture" of their unborn child with pelvic ultrasound examinations of the uterus and fetus. Ultrasound imaging is used extensively for evaluating the eyes, pelvic and abdominal organs, heart, and blood vessels, and can help a physician determine the source of pain, swelling, or infection in many parts of the body. Because ultrasound provides real-time images, it can also be used to guide procedures such as needle biopsies, in which needles are used to sample cells from organs for laboratory testing. Ultrasound is now being used to image the breasts and to guide biopsy of breast cancer (see the Ultrasound-Guided Breast Biopsy page). Ultrasound is also used to evaluate superficial structures, such as the thyroid gland and scrotum (testicles).

Doppler ultrasound is a special technique used to examine blood flow. Doppler images can help the physician to see and evaluate:

Blockages to blood flow (such as clots).
Build-up of plaque inside the vessel.
Congenital malformation.

Hysterosonography

Hysterosonography, also known as sonohysterography or saline infusion sonography, is a minimally invasive ultrasound technique used in women to view the inside of the uterus. Sterile saline is injected into the endometrial cavity through a small catheter while a transvaginal ultrasound is performed. This allows real-time imaging of the uterus as the saline is put inside. The saline fills and distends (expands) the endometrial cavity, providing good visualization of the anatomic structures within.

Hysterosonography is often used to investigate uterine abnormalities in women who experience infertility or multiple miscarriages. It is also a valuable technique in the evaluation of unexplained vaginal bleeding. Such conditions can result from uterine abnormalities such as congenital defects, masses, adhesions (or scarring), polyps, fibroids or atrophy. Hysterosonography is performed by inserting a small catheter into the uterus and filling it with sterile saline. When the saline is inserted, it pushes the walls of the endometrium apart and allows a clear picture to be formed of its shape and size. If any part of the endometrial cavity appears irregular, it should be apparent to the radiologist or sonographer.

Usually, a baseline transvaginal ultrasound examination is performed first to view the endometrium, or the lining of the uterus. When further evaluation of the endometrium is required—such as if irregular thickening of the endometrium is seen or if displacement by fibroids is found—hysterosonography can be used as a more in-depth investigation method to view the abnormalities and their potential causes. Determining the locations of certain abnormalities, such as fibroids or polyps can be important when establishing a treatment or management strategy for a patient’s particular condition.

Obstetric Ultrasound

Obstetric ultrasound refers to the specialized use of sound waves to visualize and thus determine the condition of a pregnant woman and her embryo or fetus.

Ultrasound: 3D view of 9 week fetus.

Obstetric ultrasound should be performed only when clinically indicated. Some indications may be:

To establish the presence of a living embryo/fetus.
To estimate the age of the pregnancy.
To diagnose congenital abnormalities.
To evaluate the position of the fetus.
To evaluate the position of the placenta.
To determine if there are multiple pregnancies.
To determine the amount of amniotic fluid around the fetus.
To check for opening or shortening of the cervix or mouth of the womb.

Ultrasound: Neonatal, 9 week fetal head.

Abdominal Ultrasound

An abdominal ultrasound image is a useful way of examining internal organs, including the liver, gallbladder, spleen, pancreas, kidneys, and bladder. Because ultrasound images are captured in real time, they can show movement of internal tissues and organs and enable physicians to see blood flow. This can help to diagnose a variety of conditions and to assess damage caused by illness.

Ultrasound: Inflamed bowel.

Ultrasound imaging is used extensively for evaluating the kidneys, liver, gallbladder, pancreas, spleen, and blood vessels of the abdomen. Because it provides real-time images, it can also be used to:

Guide procedures such as needle biopsies, in which needles are used to sample cells from organs for laboratory testing.
Help a physician determine the source of many abdominal pains, such as stones in the gall bladder or kidney, or an inflamed appendix.
Help identify the cause for enlargement of an abdominal organ.

Doppler ultrasound is a special type of ultrasound study that examines major blood vessels. These images can help the physician to see and evaluate:

Blockages to blood flow, such as clots.
Build-up of plaque inside the vessel.
Congenital malformation.

Ultrasound: Splenic vasculature.

With knowledge about the speed and volume of blood flow gained from an ultrasound image, the physician can often determine whether a patient is a good candidate for a procedure like angioplasty.

Pediatric Abdominal Ultrasound Imaging

In children, an abdominal ultrasound image is a useful way of examining internal organs, including the appendix, liver, gallbladder, spleen, pancreas, intestines, kidneys and bladder. Ultrasound is particularly valuable for evaluating abdominal pain in young children.

Ultrasound: Neonatal scan of lung,
liver and bowel.

After traumatic injury, appendicitis is the most common reason for emergency abdominal surgery. Appendicitis can occur at any age, but is most common in young people ages 11 to 20. Ultrasound imaging is commonly used to help make the diagnosis of appendicitis in children. Ultrasound is fast, accurate and painless, does not require the child to remain still for long periods, and the equipment is less intimidating than the large tunnels of a magnetic resonance imaging (MRI) or computed tomography (CT) scan.

Ultrasound imaging can:

Help a physician determine the source of abdominal pain, such as stones, abscesses or an inflamed appendix.
Guide procedures such as needle biopsies, in which needles are used to sample cells from organs for laboratory testing.
Help identify the cause for enlargement of an abdominal organ.
Localize abnormal fluid in the abdomen.

Carotid Ultrasound Imaging

In a carotid ultrasound exam, it is the carotid arteries, which are the large vessels in the neck that deliver blood to the brain, being examined. Carotid ultrasound can depict plaque that narrows the artery and may limit the free flow of blood to the brain.

Ultrasound: Carotid bifurcation.

Unlike x-rays, ultrasound requires no exposure to ionizing radiation, meaning that repeat imaging may be carried out without concern of accumulating radiation exposure. In addition, carotid ultrasound is a real-time technique that provides a picture of blood flow as it is at the very moment of imaging.

The most frequent reason for a carotid ultrasound exam is to detect narrowing, or stenosis, of the carotid artery, which substantially increases the risk of stroke. If your primary care physician detects high blood pressure or a carotid bruit (pronounced brU-E)—an abnormal sound in the neck that is heard with the stethoscope—carotid ultrasound may be needed. Other risk factors calling for ultrasound are advanced age, diabetes, elevated blood cholesterol, and a family history of stroke or heart disease.

If the exam shows narrowing of one or both carotid arteries, your physician may suggest medication, noninvasive angiography, or an operation to restore normal blood flow to the brain. In this way a stroke may be prevented.

Ultrasound: Femoral artery.

Other reasons for performing carotid ultrasound are:

To locate a hematoma, a collection of clotted blood that may slow and eventually stop blood flow.
To detect dissection of the carotid artery, a split between layers of the artery wall that may lead to obstruction of blood flow or a weakening of the wall of the artery.
To check the state of the carotid artery after surgery to restore normal blood flow.
To verify the position of a metal stent placed to maintain carotid blood flow.

Ultrasound of the Musculoskeletal System

An ultrasound image is a useful way of examining the musculoskeletal system of the body to detect problems with muscles, tendons, ligaments, joints and soft tissue. Ultrasound images are captured in real time, so they can often show movement, function and anatomy, as well as enable radiologists to diagnose a variety of conditions and assess damage after an injury or illness.

Ultrasound: 3D view of external
jugular vein.

Ultrasound images can be useful in diagnosing tendon tears, such as tears of the rotator cuff in the shoulder or Achilles tendon in the ankle. Abnormalities of the muscles can also be seen, such as tears and soft-tissue masses. Bleeding or other fluid collections within the muscles, bursae and joints can also be detected. Ultrasound has not proven useful in detecting whiplash injuries or other causes of back pain.

Pelvic Ultrasound

For women, pelvic ultrasound is most often used to examine the uterus and ovaries and, during pregnancy, to monitor the health and development of the embryo or fetus. In men, a pelvic ultrasound usually focuses on the bladder and the prostate gland. Ultrasound images are captured in real-time, so they can show movement of internal tissues and organs, such as the flow of blood in arteries and veins.

Ultrasound: Pelvic kidney.

Millions of expectant parents have seen the first "picture" of their unborn child thanks to pelvic ultrasound examinations of the uterus and fetus (see the Ultrasound-Obstetric page). However, monitoring of fetal development is not the only reason for a pelvic ultrasound exam.

For women, ultrasound examinations can help determine the causes of pelvic pain, abnormal bleeding or other menstrual problems. Ultrasound images can also help to identify palpable masses such as ovarian cysts and uterine fibroids, as well as ovarian or uterine cancers. Hysterosonography is a relatively new procedure in which sterile saline is injected into the uterus while a transvaginal sonogram is performed. The purpose is to distend the uterine cavity (endometrial cavity) to look for polyps, fibroids or cancer, especially in patients with abnormal uterine bleeding. Other applications include evaluation of the uterine cavity looking for uterine anomalies (abnormal uterine shapes since birth) or scars. The saline outlines the lesion and allows for easy visualization and measurement. Some physicians also use hysterosonography for patients with infertility. Saline and air are injected into the uterus and the physician looks for air bubbles passing through the fallopian tubes, which would indicate patency of the fallopian tubes. See the Hysterosonography page for more information.

In men, pelvic ultrasound is a valuable tool for evaluating the prostate gland, as well as the seminal vesicles.

A pelvic ultrasound exam can help identify stones, tumors and other disorders in the urinary bladder in men and women. Because ultrasound provides real-time images, it can also be used to guide procedures, like needle biopsies, in which a needle is used to sample cells from an abnormal area for laboratory testing. Doppler sonography is another method of ultrasound that can be used to evaluate blood flow in pelvic vessels.

Prostate Ultrasound

Prostate ultrasound is used to detect possible disorders within a man's prostate gland. Ultrasound images can indicate when the prostate is enlarged or when there is an abnormal growth that might be cancer.

For men, a transrectal ultrasound of the prostate gland may be warranted if a blood test result is elevated or if a nodule is felt by a physician during a routine physical exam or prostate cancer screening exam. An ultrasound exam can also indicate other types of prostate conditions, such as inflammation of the prostate, or it can be used to help diagnose the reasons for a man's infertility.

Because ultrasound provides real-time images, it also can be used to guide procedures, such as needle biopsies, in which a needle is used to sample cells from an abnormal area for laboratory testing.

Scrotal Ultrasound

Ultrasound or sonography involves sending sound waves into the body. These sound waves are reflected off the internal organs and are recorded by special instruments that create images of anatomic parts. No ionizing radiation (x-ray) is involved in ultrasound imaging. Ultrasound images are captured in real-time so they can show movement of internal tissues and organs, such as the flow of blood in arteries and veins.

Ultrasound imaging of the scrotum is the primary imaging method used to evaluate disorders of the testicles and surrounding areas. It is used when a patient is experiencing pain or swelling in the scrotum, a mass has been felt by the patient or doctor, or there's been trauma to the scrotal area.

For males, ultrasound is a valuable tool for evaluating the testes, the epididymis (a tube that collects sperm made by the testicles) and the prostate. Scrotal ultrasound imaging can help determine the cause of testicular pain or swelling. Some of the problems ultrasound imaging can identify include: inflammation of the scrotum, an absent or undescended testicle, testicular torsion, abnormal blood vessels or a lump or tumor.

A sudden onset of pain in the scrotum is very serious. The most common cause of scrotal pain is epididymitis, an inflammation of the epididymis. It is treatable with antibiotics. Left untreated, this condition can lead to an abscess or loss of blood to the testicles.

Ultrasound can detect an absent or undescended testicle as well. In rare cases a testicle may fail to develop. More often, patients have an undescended testicle. It is estimated that approximately three percent of full-term baby boys have undescended testicles. It's important to diagnose an undescended testicle because it has a very high probability of developing cancer if left untreated.

Ultrasound can identify testicular torsion, the twisting of the spermatic cord that contains the vessels that supply blood to the scrotum. Caused by abnormally loose attachments of tissues that are formed during fetal development, torsion commonly appears during adolescence and is very painful. Torsion requires immediate surgery to avoid permanent damage to the testes.

Ultrasound also can be used to locate and evaluate masses (lumps or tumors) in the scrotum. The majority of scrotal masses are located outside of the testes. Most masses found outside the testicles are benign or non-cancerous; most inside the testicles are malignant or cancerous. Collections of fluid and abnormalities of the blood vessels may appear as masses and need to be assessed by ultrasound.

Ultrasound of the Thyroid

Ultrasound is a painless, useful way of examining many of the body's internal organs, including the thyroid.

Ultrasound: Large thyroid mass coded harmonics.

A physician may use an ultrasound examination of the neck to help diagnosis a lump in the thyroid or a thyroid that is not functioning properly. The thyroid gland is located in front of the neck just below the Adam's apple and is shaped like a butterfly, with two lobes on either side of the neck connected by a narrow band of tissue. It is one of nine endocrine glands located throughout the body that make and send hormones into the bloodstream. These hormones target specific body functions and affect virtually every organ, tissue and cell in the body.

The thyroid gland produces thyroid hormones. Thyroid hormones set the rate at which your body carries on its necessary functions (metabolic rate). Some of the functions controlled by thyroid hormones include heart rate, cholesterol level, body weight, energy level, muscle strength, skin condition and vision.

The most common diseases of this gland result when the thyroid becomes overactive or underactive. An overactive thyroid, also called hyperthyroidism and Grave's disease, produces more thyroid hormone than is needed. The underactive thyroid, called hypothyroidism, does not produce enough hormone. Other common conditions of the thyroid include an enlarged thyroid, often called a goiter, and lump in the gland.

Vascular Ultrasound

An ultrasound image is a useful way of evaluating the body's circulatory system. Ultrasound images are captured in real-time, so they can help radiologists monitor the blood flow to organs and tissues throughout the body, as well as evaluate the placement and success of repair, such as after arterial bypass surgery. With ultrasound images, radiologists can locate and identify blockages (stenosis) and abnormalities like blood clots, plaque or emboli and help plan for their effective treatment.

Ultrasound: Renal transplant.

Ultrasound imaging of the body's veins and arteries can help the radiologist see and evaluate blockages to blood flow, such as clots in veins and plaque in arteries. With knowledge about the arterial blood flow gained from an ultrasound image, the radiologist can often determine whether a patient is a good candidate for a procedure like angioplasty. Ultrasound images may also be used to plan or review the success of procedures that graft or bypass blood vessels—such as renal (relating to the kidney) artery bypass. Ultrasound of the veins may reveal blood clots that require treatment, such as anticoagulant therapy (blood thinner), or filters to prevent clots from traveling to the lungs (embolism).

Ultrasound of the vascular system also provides a fast, noninvasive means of identifying blockages of blood flow in the neck arteries to the brain that might produce a stroke or mini-stroke.

Venous Ultrasound

When a blood clot develops inside a vein, venous ultrasound can show the clot and also the slowing or complete block of blood flow that it causes.

Ultrasound: Common femoral vein thrombosis.

The most common reason for a venous ultrasound exam is to search for blood clots, especially in the veins of the leg. These clots may break off and pass into the lungs, where they can cause a dangerous condition called pulmonary embolism. If found in time, there are treatments that can prevent this from happening.

Other reasons to do a venous ultrasound study:

Find the cause of long-standing leg swelling. In people with varicose veins, a common condition, the valves that keep blood flowing in the right direction may not work well, and venous ultrasound can help the surgeon decide how best to deal with this condition.
Aid placement of a needle or catheter in a large interior vein. Sonography can help locate the exact site of the vein and avoid complications, such as bleeding or air in the chest cavity.
Map out the veins in the leg or arm so that segments may be removed and used to bypass an area of disease. An example is using pieces of vein from the leg to surgically bypass narrowed coronary arteries.
Examine a blood vessel graft used for dialysis if it is not working as expected; an area of narrowing in the graft may be responsible.