Carotid (kuh-ROT-id) ultrasound is a safe, painless procedure that uses sound waves to examine the structure and function of the carotid arteries in your neck.
Your two carotid arteries are located on each side of your neck. Carotid arteries deliver blood from your heart to your brain.
Carotid ultrasound is usually used to test for blocked or narrowed carotid arteries, which can indicate an increased risk of stroke. Results from a carotid ultrasound can help your doctor determine what kind of treatment you may need to lower your risk of stroke.
Why It's Done
The primary purpose of a carotid ultrasound is to test for narrowed carotid arteries that indicate an increased risk of stroke.
Narrowing of carotid arteries is usually caused by plaque — a buildup of fat, cholesterol, calcium and other substances that circulate in the bloodstream. Early detection of narrowed carotid arteries enables your doctor to begin treatments to improve blood flow to your brain and decrease your risk of stroke.
Your doctor may recommend a carotid ultrasound if you have medical conditions that increase the risk of stroke, including:
- High blood pressure
- High cholesterol
- Family history of stroke or heart disease
- Recent transient ischemic attack (TIA) or stroke
- Abnormal sound in carotid arteries (bruit), detected by your doctor using a stethoscop
You'll have a Doppler ultrasound that evaluates the blood flow through your carotid arteries.
A carotid ultrasound may be used in combination with other tests to screen for narrowed or blocked blood vessels in other areas of your body, including:
- Abdominal ultrasound. You may have an abdominal ultrasound to test for conditions affecting the blood vessels or organs in your abdominalarea.
- Ankle-brachial index test. This test measures and compares your ankle's blood pressure and your arm's blood pressure. The test can indicatereduced or blocked blood flow to your legs
Other uses of carotid ultrasound
Your doctor also may order a carotid ultrasound to:
- Evaluate the structure and function of the artery after surgery to remove plaques (carotid endarterectomy)
- Evaluate the placement and treatment effect of a stent, a mesh tube used to improve blood flow through an artery by mechanically decreasing the narrowing
- Locate a collection of clotted blood (hematoma) that may inhibit blood flow
- Detect other abnormalities in the structure of a carotid artery that may disrupt blood flow
How You Prepare
You can take the following steps to prepare for your appointment:
- Call the day before the exam to confirm the time and location of the exam.
- Wear a comfortable shirt with no collar or an open collar.
- Don't wear a necklace or dangling earrings.
Unless your doctor or the radiology lab provides special instructions, you shouldn't need to make any other preparations.
What You Can Expect
A technician (sonographer) conducts the test with a small, hand-held device called a transducer. The transducer emits sound waves and records the echo as the waves bounce off tissues, organs and blood cells.
A computer translates the echoed sound waves into a live-action image on a monitor. In a Doppler ultrasound, the information about the rate of blood flow is translated into a graph.
A carotid ultrasound usually takes about 30 minutes.During the procedure
You'll likely lie on your back during the procedure. The ultrasound technician (sonographer) may gently adjust the position of your head to improve access to the side of your neck..
The sonographer will apply a warm gel to your skin above the site of each carotid artery. The gel helps eliminate the formation of air pockets between your skin and the transducer. The sonographer then gently presses the transducer against the side of your neck in order for the instrument to send and receive sound waves.
You shouldn't feel any discomfort during the procedure. If you do, tell the sonographer.
A doctor who specializes in imaging tests (radiologist) will review and interpret the results of your carotid ultrasound. He or she will prepare a report for the doctor who ordered the exam, such as your primary care doctor, a doctor trained in heart and blood vessel conditions (cardiologist), or a doctor trained in brain and nervous system conditions (neurologist).
The radiologist may also discuss the results of the test with you immediately after the procedure.
The doctor who ordered the test will explain to you what the carotid ultrasound revealed and how the results will affect your medical care.
If the test reveals you're at risk of a stroke, your doctor may recommend the following therapies, depending on the severity of blockage in your arteries:
- Eat a healthy diet, including fruits, vegetables and whole-grain breads and cereals, and limit saturated fat
- Participate in a regular exercise routine
- Keep a healthy weight
- Don't smoke and try to stay away from secondhand smoke
- Take medications to lower blood cholesterol and blood pressure
- Take medications to prevent blood clots
- Have a surgical procedure to remove carotid artery plaques (carotid endarterectomy)
- Have a surgical procedure to open up and support your carotid arteries (carotid angioplasty and stenting)
If your doctor ordered the carotid ultrasound as a follow-up to a surgical procedure, your doctor can explain whether the treatment is working as planned and whether you'll need additional treatment or follow-up exams.
If the results of the carotid ultrasound are unclear, your doctor may order additional imaging tests for more detailed images of your carotid arteries, including:
- Computerized tomography (CT) scan. A CT scan uses a series of X-rays to produce detailed images of soft tissues in your body. Your doctor may inject a dye into a vein to highlight your carotid arteries.
- Magnetic resonance imaging (MRI). An MRI uses a magnetic field and radio waves to produce detailed images of soft tissues in your body.
Chest X-rays produce images of your heart, lungs, blood vessels, airways, and the bones of your chest and spine. Chest X-rays can also reveal fluid in or around your lungs or air surrounding a lung.
If you go to your doctor or the emergency room with chest pain, a chest injury or shortness of breath, you will typically get a chest X-ray. The image helps your doctor determine whether you have heart problems, a collapsed lung, pneumonia, broken ribs, emphysema, cancer or any of several other conditions.
The chest X-ray is a common way to diagnose disease. But it can also be used to tell whether a certain treatment is working. Some people have a series of chest X-rays done over time, to track whether a health problem is getting better or worse.
Why It's Done
Chest X-rays are a common type of exam. A chest X-ray is often among the first procedures you'll undergo if your doctor suspects you have heart or lung disease. It can also be used to check how you are responding to treatment.
A chest X-ray can reveal many things inside your body, including:
- The condition of your lungs. Chest X-rays can detect cancer, infection or air collecting in the space around a lung (pneumothorax). They can also show chronic lung conditions, such as emphysema or cystic fibrosis, as well as complications related to these conditions.
- Heart-related lung problems. Chest X-rays can show changes or problems in your lungs that stem from heart problems. For instance, fluid in your lungs (pulmonary edema) can be a result of congestive heart failure.
- The size and outline of your heart. Changes in the size and shape of your heart may indicate heart failure, fluid around the heart (pericardial effusion) or heart valve problems.
- Blood vessels. Because the outlines of the large vessels near your heart — the aorta and pulmonary arteries and veins — are visible on X-rays, they may reveal aortic aneurysms, other blood vessel problems or congenital heart disease.
- Calcium deposits. Chest X-rays can detect the presence of calcium in your heart or blood vessels. Its presence may indicate damage to your heart valves, coronary arteries, heart muscle or the protective sac that surrounds the heart. Calcium deposits in your lungs are most often from an old, resolved infection.
- Fractures. Rib or spine fractures or other problems with bone may be seen on a chest X-ray.
- Postoperative changes. Chest X-rays are useful for monitoring your recovery after you've had surgery in your chest, such as on your heart, lungs or esophagus. Your doctor can look at any lines or tubes that were placed during surgery to check for air leaks and areas of fluid or air buildup.
- A pacemaker, defibrillator or catheter. Pacemakers and defibrillators have wires (leads) attached to your heart to make sure your heart rate and rhythm are normal. Catheters are small tubes used to deliver medications or for dialysis. A chest X-ray usually is taken after placement of such medical devices to make sure everything is positioned correctly.
You may be concerned about radiation exposure from chest X-rays, especially if you have them regularly. But the amount of radiation from a chest X-ray is low — even lower than what you're exposed to through natural sources of radiation in the environment.
Even though the benefits of an X-ray outweigh the risk, you may be given a protective apron if you need more than one image. Tell your doctor if you're pregnant or might be pregnant. The procedure can be performed in a way to protect your abdomen from the radiation.
How You Prepare
Before the chest X-ray, you generally undress from the waist up and wear an exam gown. You'll need to remove jewelry from the waist up, too, since both clothing and jewelry can obscure the X-ray images.
What You Can Expect
During the procedure, your body is positioned between a machine that produces the X-rays and a plate that creates the image digitally or with X-ray film. You may be asked to move into different positions in order to take views from both the front and the side of your chest.
During the front view, you stand against the plate, hold your arms up or to the sides and roll your shoulders forward. The X-ray technician may ask you to take a deep breath and hold it for several seconds. Holding your breath after inhaling helps your heart and lungs show up more clearly on the image.
During the side views, you turn and place one shoulder on the plate and raise your hands over your head. Again, you may be asked to take a deep breath and hold it.
Having X-rays taken is generally painless. You don't feel any sensation as the radiation passes through your body. If you have trouble standing, you may be able to have the exam while seated or lying down.
A chest X-ray produces a black-and-white image of the organs in your chest. Structures that block radiation appear white, and structures that let radiation through appear black.
Your bones appear white because they are very dense. Your heart also appears as a lighter area. Your lungs are filled with air and block very little radiation, so they appear as darker areas on the images.
A radiologist — a doctor trained in interpretation of X-rays and other imaging exams — analyzes the images, looking for clues that may suggest if you have heart failure, fluid around your heart, cancer, pneumonia or another condition.
Your own doctor will discuss the results with you as well as what treatments or other tests or procedures may be necessary.
CT - Scan
Computerized tomography (CT scan) — also called CT — combines a series of X-ray views taken from many different angles and computer processing to create cross-sectional images of the bones and soft tissues inside your body..
The resulting images can be compared to looking down at single slices of bread from a loaf. Your doctor will be able to look at each of these slices individually or perform additional visualization to view your body from different angles. In some cases, CT images can be combined to create 3-D images. CT scan images can provide much more information than do plain X-rays.
A CT scan has many uses, but is particularly well suited to quickly examine people who may have internal injuries from car accidents or other types of trauma. A CT scan can be used to visualize nearly all parts of the body.
Why It's Done
Your doctor may recommend a CT scan to help:
- Diagnose muscle and bone disorders, such as bone tumors and fractures
- Pinpoint the location of a tumor, infection or blood clot
- Guide procedures such as surgery, biopsy and radiation therapy
- Detect and monitor diseases and conditions such as cancer, heart disease, lung nodules and liver masses
- Detect internal injuries and internal bleeding
During a CT scan, you're briefly exposed to much more radiation than you would be during a plain X-ray. This radiation from imaging tests has a very small potential to increase your risk of cancer. Still, CT scans have many benefits that may outweigh potential risks. Doctors use the lowest dose of radiation whenever possible. Newer machines and techniques may expose you to less radiation. Talk with your doctor about the benefits and risks of your CT scan.Harm to unborn babies
Tell your doctor if you're pregnant. Another type of exam may be recommended, such as ultrasound or magnetic resonance imaging (MRI), to avoid the risk of exposing your fetus to the radiation.Reactions to contrast material
In certain cases, your doctor may recommend you receive a special dye called a contrast material through a vein in your arm before your CT scan. Although rare, the contrast material can cause medical problems or allergic reactions. Most reactions are mild and result in a rash or itchiness. In rare instances, an allergic reaction can be serious and potentially life-threatening. Tell your doctor if you've ever had a reaction to contrast material.
How You Prepare
How you prepare for a CT scan depends on which part of your body is being scanned. You may be asked to:
- Take off some or all of your clothing and wear a hospital gown
- Remove any metal objects, such as a belt or jewelry, which might interfere with image results
- Stop eating for a few hours before your scan.
A special dye called a contrast material is needed for some CT scans, to help highlight the areas of your body being examined. The contrast material blocks X-rays and appears white on images, which can help emphasize blood vessels, intestines or other structures.
Contrast material can enter your body in a variety of ways:
- Oral. If your esophagus or stomach is being scanned, you may need to swallow a liquid that contains contrast material. This drink may taste unpleasant.
- Injection. Contrast agents can be injected through a vein in your arm, to help view your gallbladder, urinary tract, liver or blood vessels. You may experience a feeling of warmth during the injection or a metallic taste in your mouth.
- Rectal. A contrast material may be inserted in your rectum to help visualize your intestines. This procedure can make you feel bloated and uncomfortable.
Preparing your small child for a scan
If your infant or toddler is having the CT scan, the doctor may recommend a sedative to keep your child calm and still. Movement blurs the images and may lead to inaccurate results. Ask your doctor how best to prepare your child.
What You Can Expect
You can have a CT scan done in a hospital or an outpatient facility. CT scans are painless and, with newer machines, typically take only a few minutes to complete.During the CT scan
CT scanners are shaped like a large doughnut standing on its side. You lie on a narrow table that slides into the "doughnut hole," which is called a gantry. Straps and pillows may help you stay in position. During a CT scan of the head, the table may be fitted with a special cradle that holds your head still.
The table will move slowly through the gantry during the CT scan, as the gantry rotates in a circle around you. Each rotation yields several images of thin slices of your body. You may hear buzzing, clicking and whirring noises.
A technologist will be nearby, in a separate room. You will be able to communicate with the technologist via intercom. The technologist may ask you to hold your breath at certain points to avoid blurring the images.After the CT scan
After the exam you can return to your normal routine. If you were given a contrast material, you may receive special instructions. In some cases, you may be asked to wait for a short time before leaving to ensure that you feel well after the exam. After the scan, you'll likely be told to drink lots of fluids to help your kidneys remove the contrast material from your body.
CT images are stored as electronic data files and usually reviewed on a computer screen. A radiologist interprets these images and sends a report to your doctor.
An echocardiogram uses sound waves to produce images of your heart. This commonly used test allows your doctor to see how your heart is beating and pumping blood. Your doctor can use the images from an echocardiogram to identify various abnormalities in the heart muscle and valves. Depending on what information your doctor needs, you may have one of several types of echocardiograms. Each type of echocardiogram has few risks involved.
Depending on what information your doctor needs, you may have one of several types of echocardiograms. Each type of echocardiogram has few risks involved.
Why It's Done
Your doctor may suggest an echocardiogram if he or she suspects problems with the valves or chambers of your heart or your heart's ability to pump. An echocardiogram can also be used to detect congenital heart defects in unborn babies.Depending on what information your doctor needs, you may have one of the following kinds of echocardiograms:
Depending on what information your doctor needs, you may have one of the following kinds of echocardiograms:
- Transthoracic echocardiogram. This is a standard, noninvasive echocardiogram. A technician (sonographer) spreads gel on your chest and thenpresses a device known as a transducer firmly against your skin, aiming an ultrasound beam through your chest to your heart. The transducer records the sound wave echoes your heart produces. Acomputer converts the echoes into moving images on a monitor. If your lungs or ribs block the view, a small amount of intravenous dye may be used to improve the images.
- Transesophageal echocardiogram. If it's difficult to get a clear picture of your heart with a standard echocardiogram, your doctor may recommenda transesophageal echocardiogram. In this procedure, a flexible tube containing a transducer is guided down your throat and into your esophagus, which connects your mouth to your stomach. From there,the transducer can obtain more-detailed images of your heart. Your throat will be numbed, and you'll have medications to help you relax during a transesophageal echocardiogram.
- Doppler echocardiogram. When sound waves bounce off blood cells moving through your heart and blood vessels, they change pitch. Thesechanges (Doppler signals) can help your doctor measure the speed and direction of the blood flow in your heart. Doppler techniques are used in most transthoracic and transesophageal echocardiograms,and they can check blood flow problems and blood pressures in the arteries of your heart that traditional ultrasound might not detect. Sometimes, the blood flow shown on the monitor is colorized to help yourdoctor pinpoint any problems (color flow echocardiogram).
- Stress echocardiogram. Some heart problems — particularly those involving the coronary arteries that supply blood to your heart muscle — occuronly during physical activity. For a stress echocardiogram, ultrasound images of your heart are taken before and immediately after walking on a treadmill or riding a stationary bike. If you're unable toexercise, you may get an injection of a medication to make your heart work as hard as if you were exercising.
There are few risks involved in a standard transthoracic echocardiogram. You may feel some discomfort similar to pulling off an adhesive bandage when the technician removes the electrodes placed on your chest during the procedure.
If you have a transesophageal echocardiogram, your throat may be sore for a few hours afterward. Rarely, the tube may scrape the inside of your throat. Your oxygen level will be monitored during the exam to check for any breathing problems caused by sedation medication.
During a stress echocardiogram, exercise or medication — not the echocardiogram itself — may temporarily cause an irregular heartbeat. Serious complications, such as a heart attack, are rare.
How You Prepare
No special preparations are necessary for a standard transthoracic echocardiogram. Your doctor will ask you not to eat for a few hours beforehand if you're having a transesophageal or stress echocardiogram. If you'll be walking on a treadmill during a stress echocardiogram, wear comfortable shoes. If you're having a transesophageal echocardiogram, you won't be able to drive afterward because of the sedating medication you'll likely receive. Before you have your transesophageal echocardiogram, be sure to make arrangements to get home.
What You Can Expect
An echocardiogram can be done in the doctor's office or a hospital. After undressing from the waist up, you'll lie on an examining table or bed. The technician will attach sticky patches (electrodes) to your body to help detect and conduct the electrical currents of your heart.
If you'll have a transesophageal echocardiogram, your throat will be numbed with a numbing spray or gel. You'll likely be given a sedative to help you relax.
During the echocardiogram, the technician will dim the lights to better view the image on the monitor. You may hear a pulsing "whoosh," which the machine is recording the blood flowing through your heart.
Most echocardiograms take less than an hour, but the timing may vary depending on your condition. During a transthoracic echocardiogram, you may be asked to breathe in a certain way or to roll onto your left side. Sometimes the transducer must be held very firmly against your chest. This can be uncomfortable — but it helps the technician produce the best images of your heart.
After the procedure
If your echocardiogram is normal, no further testing may be needed. If the results are concerning, you may be referred to a heart specialist (cardiologist) for more tests. Treatment depends on what's found during the exam and your specific signs and symptoms. You may need a repeat echocardiogram in several months or other diagnostic tests, such as a cardiac computerized tomography (CT) scan or coronary angiogram.
Your doctor will look for healthy heart valves and chambers, as well as normal heartbeats. Information from the echocardiogram may show:
- Heart sizeWeakened or damaged heart valves, high blood pressure or other diseases can cause the chambers of your heart to enlarge. Your doctor can use an echocardiogram to evaluate the need for treatment or monitor treatmenteffectiveness.
- Pumping strength An echocardiogram can help your doctor determine your heart's pumping strength. Specific measurements may include the percentage of blood that's pumped out of a filled ventricle with each heartbeat (ejection fraction) or the volume of blood pumped by the heart in one minute (cardiac output). If your heart isn't pumping enough blood to meet your body's needs, heart failure may be a concern.
- Damage to the heart muscle During an echocardiogram, your doctor can determine whether all parts of the heart wall are contributing normally to your heart's pumping activity. Parts that move weakly may have been damaged during a heart attack or be receiving too little oxygen. This may indicate coronary artery disease or various other conditions.
- Valve problems An echocardiogram shows how your heart valves move as your heart beats. Your doctor can determine if the valves open wide enough for adequate blood flow or close fully to prevent blood leakage. Abnormal blood flow patterns and certain conditions, such as aortic valve stenosis when the heart's aortic valve is narrowed can be detected as well.
- Heart defects Many heart defects can be detected with an echocardiogram, including problems with the heart chambers, abnormal connections between the heart and major blood vessels, and complex heart defects that are present at birth. Echocardiograms can even be used to monitor a baby's heart development before birth.
Electrocardiogram (ECG or EKG)
An electrocardiogram is used to monitor your heart. Each beat of your heart is triggered by an electrical impulse normally generated from special cells in the upper right chamber of your heart.
An electrocardiogram — also called an ECG or EKG — records these electrical signals as they travel through your heart. Your doctor can use an electrocardiogram to look for patterns among these heartbeats and rhythms to diagnose various heart conditions.
An electrocardiogram is a noninvasive, painless test. The results of your electrocardiogram will likely be reported the same day it's performed, and your doctor will discuss them with you at your next appointment.
Why It's Done
An electrocardiogram is a painless, noninvasive way to diagnose many common types of heart problems. Your doctor may use an electrocardiogram to detect:
- Irregularities in your heart rhythm (arrhythmias)
- Heart defects
- Problems with your heart's valves
- Blocked or narrowed arteries in your heart (coronary artery disease
- A heart attack, in emergency situations
- A previous heart attack
An electrocardiogram is a safe procedure. There may be minor discomfort, similar to removing a bandage, when the electrodes taped to your chest to measure your heart's electrical signals are removed. Rarely, a reaction to the electrodes may cause redness or swelling of the skin.
A stress test, in which an ECG is performed while you exercise or after you take medication that mimics effects of exercise, may cause irregular heartbeats or, rarely, a heart attack. These side effects are caused by the exercise or medication, not the ECG itself.
There isn't any risk of electrocution during an electrocardiogram. The electrodes placed on your body only record the electrical activity of your heart. They don't emit electricity.
How You Prepare
No special preparations are necessary. However, avoid drinking cold water or exercising immediately before an electrocardiogram. Cold water can produce potentially misleading changes in one of the electrical patterns recorded during the test. Physical activity, such as climbing stairs, may increase your heart rate.
What You Can Expect
An electrocardiogram can be done in the doctor's office or hospital, and is often performed by a technician. After changing into a hospital gown, you'll lie on an examining table or bed. Electrodes often 12 to 15 will be attached to your arms, legs and chest. The electrodes are sticky patches applied with a gel to help detect and conduct the electrical currents of your heart. If you have hair on the parts of your body where the electrodes will be placed, the technician may need to shave the hair so that the electrodes stick properly.
You can breathe normally during the electrocardiogram. Make sure you're warm and ready to lie still, however. Moving, talking or shivering may distort the test results. A standard ECG takes just a few minutes.
If you have a heartbeat irregularity that tends to come and go, it may not be captured during the few minutes a standard ECG is recording. To work around this problem, your doctor may recommend another type of ECG:
- Holter monitoring. Also known as an ambulatory ECG monitor, a Holter monitor records your heart rhythms for an entire 24-hour period. Wires from electrodes on your chest go to a battery-operated recording device carried in your pocket or worn on a belt or shoulder strap. While you're wearing the monitor, you'll keep a diary of your activities and symptoms. Your doctor will compare the diary with the electrical recordings to try to figure out the cause of your symptoms.
- Event recorder. If your symptoms don't occur often, your doctor may suggest wearing an event recorder. This device is similar to a Holter monitor, but it allows you to record your heart rhythm just when the symptoms are happening. You can send the ECG readings to your doctor through your phone line.
- Stress test. If your heart problems occur most often during exercise, your doctor may ask you to walk on a treadmill or ride a stationary bike during an ECG. This is called a stress test. If you have a medical condition that makes it difficult for you to walk, medication may be injected to mimic the effect of exercise on the heart.
After the procedure
Usually, your doctor will be able to tell you the results of your ECG the same day it's performed. If your electrocardiogram is normal, you may not need any other tests. If the results show there's a problem with your heart, you may need a repeat ECG or other diagnostic tests, such as an echocardiogram. Treatment depends on what's causing your signs and symptoms.
Your doctor will look for a consistent, even heart rhythm and a heart rate between 50 and 100 beats a minute. Having a faster, slower or irregular heartbeat provides clues about your heart health, including:
- Heart rate. Normally, heart rate can be measured by checking your pulse. But an ECG may be helpful if your pulse is difficult to feel or too fast or too irregular to count accurately.
- Heart rhythm. An ECG can help your doctor identify an unusually fast heartbeat (tachycardia), unusually slow heartbeat (bradycardia) or other heart rhythm irregularities (arrhythmias). These conditions may occur when any part of the heart's electrical system malfunctions. In other cases, medications, such as beta blockers, psychotropic drugs or amphetamines, can trigger arrhythmias.
- Heart attack. An ECG can often show evidence of a previous heart attack or one that's in progress. The patterns on the ECG may indicate which part of your heart has been damaged, as well as the extent of the damage.
- Inadequate blood and oxygen supply to the heart. An ECG done while you're having symptoms can help your doctor determine whether chest pain is caused by reduced blood flow to the heart muscle, such as with the chest pain of unstable angina.
- Structural abnormalities. An ECG can provide clues about enlargement of the chambers or walls of the heart, heart defects and other heart problems.
Diagnostic ultrasound, also called sonography or diagnostic medical sonography, is an imaging method that uses high-frequency sound waves to produce images of structures within your body. The images can provide valuable information for diagnosing and treating a variety of diseases and conditions.
Most ultrasound examinations are done using a sonar device outside your body, though some ultrasound examinations involve placing a device inside your body.
Why It's Done
Ultrasound is used for a variety of reasons, including to:
- View the uterus and ovaries of a pregnant woman and assess her fetus
- Diagnose gallbladder disease
- Evaluate flow in blood vessels
- Guide a needle for biopsy or tumor treatment
- Evaluate a breast lump
- Check a thyroid gland
- Diagnose some cancers
- Reveal genital and prostate abnormalities
Diagnostic ultrasound is a safe procedure that uses low-power sound waves. There are no known risks.
Although ultrasound is a valuable tool, it has limitations. Sound doesn't travel well through air or bone, so ultrasound isn't effective at imaging parts of your body that have gas in them or are hidden by bone. To view these areas, your doctor may order other imaging tests, such as CT or MRI scans or X-rays.
How You Prepare
Most ultrasound exams require no preparation, with a few exceptions:
- For some ultrasound exams, such as of the gallbladder, your doctor may ask that you not eat or drink for up to 6 hours before the exam.
- Other ultrasound exams, such as of the pelvis, may require a full bladder, so your doctor might ask you to drink up to six glasses of water two hours before the exam and not urinate until the exam is completed.
When scheduling your ultrasound, ask your doctor for specific instructions for your exam.
What You Can Expect
During an ultrasound exam, you may need to remove jewelry and some or all of your clothing, change into a gown, and lie on an examination table. Gel is applied to your skin to keep air pockets that can block the sound waves from forming.
A trained technician (sonographer) presses a small, hand-held device (transducer), about the size of a bar of soap, against your skin over the area being examined, moving it as necessary to capture the image. The transducer sends sound waves into your body, collects sound waves that bounce back and sends them to a computer, which creates the images.
Some ultrasounds are done inside your body. A transducer is attached to a probe that's inserted into a natural opening in your body. Examples of these exams include:
- Transesophageal echocardiogram. A transducer is inserted into your esophagus, usually with sedation, to obtain heart images.
- Transrectal ultrasound. A transducer is inserted into a man's rectum to view his prostate.
- Transvaginal ultrasound. A transducer is inserted into a woman's vagina to view her uterus and ovaries.
Ultrasound is usually painless. However, you may experience mild discomfort as the sonographer guides the transducer over your body, especially if you're required to have a full bladder.
A typical ultrasound exam takes from 30 minutes to an hour.
When your exam is complete, a physician trained to interpret imaging studies (radiologist) analyzes the images and sends a report to your doctor. Your doctor will share the results with you.
You should be able to return to normal activities immediately after an ultrasound.