Ultrasonography

It uses a small probe called a transducer and gel placed directly on the skin

Because images are captured in real-time, they can show the structure and movement of the body's internal organs. They can also show blood flowing through blood vessels.

Conventional ultrasound displays the images in thin, flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats the sound wave data into 3-D images.

Doppler ultrasound study may be part of an ultrasound examination.

Doppler ultrasound is a special ultrasound technique that evaluates movement of materials in the body. It allows the doctor to see and evaluate blood flow through arteries and veins in the body.

There are three types of Doppler ultrasound:

Color Doppler uses a computer to convert Doppler measurements into an array of colors to show the speed and direction of blood flow through a blood vessel.

Power Doppler is a newer technique that is more sensitive than color Doppler and capable of providing greater detail of blood flow, especially when blood flow is little or minimal. Power Doppler, however, does not help the radiologist determine the direction of blood flow, which may be important in some situations.

Spectral Doppler displays blood flow measurements graphically, in terms of the distance traveled per unit of time, rather than as a color picture. It can also convert blood flow information into a distinctive sound that can be heard with every heartbeat.

Ultrasound examinations can help to diagnose a variety of conditions and to assess organ damage following illness.

Ultrasound is used to help physicians evaluate symptoms such as:

pain

swelling

infection

Ultrasound is a useful way of examining many of the body's internal organs, including but not limited to the:

heart and blood vessels, including the abdominal aorta and its major branches

liver

gallbladder

spleen

pancreas

kidneys

bladder

uterus, ovaries, and unborn child (fetus) in pregnant patients

eyes

thyroid and parathyroid glands

scrotum (testicles)

brain in infants

hips in infants

spine in infants

ltrasound is also used to:

guide procedures such as needle biopsies, in which needles are used to sample cells from an abnormal area for laboratory testing.

image the breasts and guide biopsy of breast cancer (see the Ultrasound-Guided Breast Biopsy page.

diagnose a variety of heart conditions, including valve problems and congestive heart failure, and to assess damage after a heart attack. Ultrasound of the heart is commonly called an "echocardiogram" or "echo" for short.

Doppler ultrasound images can help the physician to see and evaluate:

blockages to blood flow (such as clots)

narrowing of vessels

tumors and congenital vascular malformations

reduced or absent blood flow to various organs, such as the testes or ovary

increased blood flow, which may be a sign of infection

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

How should I prepare?

Wear comfortable, loose-fitting clothing. You may need to remove all clothing and jewelry in the area to be examined.

You may be asked to wear a gown during the procedure.

Preparation for the procedure will depend on the type of examination you will have. For some scans your doctor may instruct you not to eat or drink for as many as 12 hours before your appointment. For others you may be asked to drink up to six glasses of water two hours prior to your exam and avoid urinating so that your bladder is full when the scan begins.

Usually there is no special preparation needed. Continue to take your usual medication. You should eat and drink normally before and after the test unless otherwise instructed. For example:

If certain parts of the tummy (abdomen) are being examined, you may be asked to eat a low-fibre diet for a day or so before the test (to minimise 'gas' in your gut).

You may be asked not to eat for several hours before a scan of the abdomen.

Occasionally for some scans, you may be given an enema to clear the bowel.

To scan the bladder or pelvis, you may be asked to drink some fluid before the test so that you have a full bladder. This is particularly likely if you are having a scan in pregnancy, or a scan of your ovaries or womb (uterus).

In some ultrasound studies, the transducer is attached to a probe and inserted into a natural opening in the body. These exams include:

Transesophageal echocardiogram. The transducer is inserted into the esophagus to obtain images of the heart.

Transrectal ultrasound. The transducer is inserted into a man's rectum to view the prostate.

Transvaginal ultrasound. The transducer is inserted into a woman's vagina to view the uterus and ovaries.

What is Doppler ultrasound used for?

To listen to the heartbeat of an unborn baby (fetus) during pregnancy.

To examine blood flow in arteries or veins in your arms or legs to see if you might have:

Deep vein thrombosis.
Peripheral arterial disease.
Injury to your veins or arteries following trauma.

What is duplex ultrasound used for?

Duplex ultrasound is most commonly used to evaluate the blood flow in various arteries and veins in the body. The scan can help diagnose the following conditions:

Widening of the main artery in the tummy (abdominal aortic aneurysm). Ultrasound scans are used in the national screening programmes across the UK for abdominal aortic aneurysm.
Blockage to an artery (an arterial occlusion).
Blood clot.
Blockage to the arteries in the neck (carotid occlusive disease).
Renal duplex examines the kidneys and their blood vessels.
Varicose veins.
Venous insufficiency (a condition where veins have a problem sending blood back to the heart).

The images below are produced from a Doppler scan of the kidney.

Types of US

Abdominal Ultrasound

An abdominal ultrasound is a useful way of examining internal organs, including the liver, gallbladder, spleen, pancreas, kidneys, and bladder. This can help to diagnose a variety of conditions and to assess the damage caused by illness. Because it provides real-time images, ultrasound 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 gallbladder or kidney.
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.

Pelvic Ultrasound Imaging

Pelvic ultrasounds are one of the most well-known forms of ultrasound, being one of the imaging test used to monitor the health of the embryo or fetus during pregnancy. Aside from maternity medicine, these ultrasounds are also used to examine the uterus, ovaries, bladder, and prostate gland.

Pelvic ultrasound is often used to diagnose conditions or the cause of conditions such as:

Pelvic pain
Abnormal bleeding
Menstrual problems
Ovarian cysts
Uterine fibroids
Ovarian and uterine cancers
Kidney and bladder stones

Transabdominal

Patients receiving a transabdominal ultrasound need to have a full urinary bladder. Like other ultrasound procedures, patients lie on their back as a gel is applied to the abdomen. The transducer is then rubbed over the examination are and releases sound waves. This is a fairly straightforward ultrasound exam.

Transvaginal Ultrasound

For a transvaginal ultrasound, a woman needs to empty her bladder the same way she would for a gynecological exam. She also lies face up on her back with feet in stirrups. The transducer of the ultrasound needs to be inserted for this test. The transducer is smaller than the standard speculum used in Pap tests. A protective cover and gel for lubrication is placed on the transducer before it is inserted in the vagina.

Only the first two to three inches of the transducer is inserted in the vagina. The doctor may move it around to obtain images from different angles. The most common reason for transvaginal pelvic ultrasounds is to look for the cause of pelvic pain. Most patients report that this exam is more comfortable than a manual gynecologic examination.

Transrectal

In order to perform an ultrasound on the prostate gland, the transducer must be inserted through the rectum so that the sound waves can travel to the prostate. As with other inserted ultrasound procedures, the transducer is covered with a protective cover and lubrication before insertion. The transducer will need to be moved around in order to obtain images from different angles. These exams are typically performed with the patient lying down on their left side and knees bent up towards the chest.

The doctor may recommend a biopsy be performed if a lesion is found during the exam. In a biopsy, the radiologist uses the ultrasound images to guide a needle towards the prostate gland and extract a sample of the abnormal tissue. Ultrasound-guided biopsies are minimally invasive and only require a small incision.

Obstetric Ultrasound Imaging

Obstetric ultrasound (OB 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. 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

You will be asked to lie on your back or side. You will also be asked to expose your lower abdominal area. The obstetric ultrasound examination takes about 30-45 minutes.

This is a painless procedure. There may be varying degrees of discomfort from pressure as the sonographer guides the transducer over your abdomen, especially if you are required to have a full bladder. At times the sonographer may have to press more firmly to get closer to the embryo or fetus to better visualize the structure. This discomfort is temporary. Also, you may dislike the feeling of the water-soluble gel applied to your abdomen. With transvaginal scanning, there may be minimal discomfort as the transducer is moved in the vagina.

Carotid & Abdominal Aorta Ultrasound Imaging

Ultrasound of the carotid arterial system 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. Ultrasound of the abdominal aorta is primarily used to evaluate for an aneurysm which is an abnormal enlargement of the aorta usually from atherosclerotic disease.

The patient is positioned on an examination table that can tilt and move. A clear gel is applied to the area that will be examined. The gel helps the transducer make a secure contact and eliminates air pockets between the transducer and the skin, since the sound waves cannot penetrate air. The sonographer or radiologist then presses the transducer firmly against the skin and sweeps along the area of interest, reviewing the images on the monitor and capturing "snapshots" as required.

Liver Ultrasound

Liver Ultrasound determines the size, shape, and function of the liver, and can be used to detect tumors.

Renal Ultrasound

Renal ultrasound determines the size, shape, and function of the kidneys, and can be useful in the detection of kidney stones, cysts, and tumors.

Vascular Ultrasound

Vascular ultrasounds are used to analyze the flow of blood through the arteries and veins.

Thyroid Ultrasound

Thyroid Ultrasound checks for underactive and overactive thyroid glands, nodules, and cysts.

Preparation for a KUB ultrasound

Empty bowel. Full bladder.

Duplex = tradiotional + doppler

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