Health Library

The Health Library is a collection of health and wellness resources created for learning and accessibility. Select a topic below for related health information or search for a topic in the search bar for more information on other medical conditions.

Diagnostic Radiology

  • A magnetic resonance angiogram (MRA) is a type of magnetic resonance imaging (MRI) scan that uses a magnetic field and pulses of radio wave energy to provide pictures of blood vessels inside the body. In many cases MRA can provide information that can't be obtained from an X-ray, ultrasound, or computed tomography (CT)...

  • Guides you through the decision to have an early fetal ultrasound. Explains when ultrasound is usually done during pregnancy and why. Lists risks and benefits. Includes interactive tool to help you decide.

  • Heart tests can help your doctor find out if you are at risk for a heart problem, if you have a heart problem, and what treatment you need. There are many heart tests. Most are noninvasive, which means that your doctor does not insert a device into your body for the test. Many of the tests provide still or moving...

  • Learn what happens before and during a thyroid scan and what the test looks for.

  • Screening tests help your doctor look for a problem before you have symptoms. Lung cancer screening is a way to find some lung cancers early, when a cure is more likely and when cancer is more treatable. If your doctor recommends lung cancer screening, you'll have a low-dose CT scan of your chest once a year. A special...

  • A computed tomography angiogram (CT angiogram) is a test that uses X-rays to provide detailed pictures of the heart and the blood vessels that go to the heart, lung, brain, kidneys, head, neck, legs, and arms. This test can show narrowed or blocked areas of a blood vessel. It can also show whether there is a bulge (...

  • Single photon-emission computed tomography (SPECT) is a test that uses a special type of camera and a tracer (a radioactive substance in liquid form) to look at organs or bones in the body. During the test, the tracer is put into a vein (intravenous, or IV) in your arm. Sometimes it's taken by mouth or inhaled through...

  • Learn what to expect when your child gets a CT scan.

  • Learn what to expect when your child gets an X-ray.

  • Learn what to expect when your child gets an MRI.

  • A swallowing study is a test that shows what your throat and esophagus do while you swallow. The test uses X-rays in real time (fluoroscopy) and records what happens when you swallow. While you swallow, the doctor and speech pathologist watch a video screen. For a swallowing study, you will swallow liquid mixed with...

  • Learn what an echocardiogram for children is and how it's done.

  • Learn what to expect when you get a CT scan.

  • Learn what to expect when you get an MRI.

  • Learn what to expect when you get an X-ray.

  • Learn how a voiding cystourethrogram (VCUG) is done and how to prepare your child for this test.

  • Learn about how to prepare and what you can expect during a screening mammogram.

  • Guides people who are at high risk for lung cancer through the decision on whether to have an annual low-dose CT screening. Discusses the benefits and risks of having screening and the risk for getting lung cancer. Includes an interactive tool to help you decide.

  • Learn when having an angiogram is helpful and when it may not be needed.

  • Hear what other people thought about as they decided whether to have a coronary angiogram.

  • Guides you through breast cancer screening choices if you have dense breasts. Discusses the benefits and risks of choosing more testing after a mammogram, such as ultrasound or MRI. Includes interactive tool to help you make your decision.

  • Learn how and why an angiogram is done.

  • Learn how you'll feel after an angiogram and how to take care of yourself at home.

  • Screening tests help your doctor look for a problem before you have symptoms. This increases your chances of finding the problem early, when it's more treatable. Studies don't show that routine screening for lung cancer is right for most people. But it may help those who have the highest risk for lung cancer—people...

  • A sonohysterogram uses ultrasound to look at the inside of your uterus. A salt (saline) solution is put in the uterus for a clearer image. Ultrasound images from a sonohysterogram can help find the cause of bleeding or problems with getting pregnant. Unlike a hysterosalpingogram, a sonohysterogram doesn't use...

  • Learn why X-rays, CT scans, and MRIs may not find the cause of your low back pain.

  • Guides through decision to have screening for abdominal aortic aneurysm. Includes pros such as finding aneurysms so that they can be treated. Also explains the possible harm that could come if the test leads to risky surgery. Includes interactive tool to help you decide.

  • Positron emission tomography (PET) is a test that uses a special type of camera and a tracer (radioactive substance) to look at organs in the body. The tracer usually is a special form of a substance (such as glucose) that collects in cells that are...

  • Guides through the decision to have magnetic resonance imaging (MRI) for low back pain. Discusses the problems an MRI can find and why it may not show the source of pain. Includes interactive tool to help you make your decision.

  • Guides through decision to have a dual-energy X-ray absorptiometry (DXA) test for osteoporosis. Explains DXA test. Includes risk factors for osteoporosis you can and cannot change. Covers benefits and risks. Includes an interactive tool to help you decide.

  • A hysterosalpingogram (HSG) is an X-ray test. It looks at the inside of the uterus and fallopian tubes and the area around them. It often is done for women who are having a hard time getting pregnant (infertility). During the test, a dye ( contrast material) is put through a thin tube. That tube is put through the...

  • Guides you through the decision to have screening tests to look for Down syndrome and birth defects. Discusses what the tests look for. Covers benefits and risks. Includes interactive tool to help you make your decision.

  • An MRI is a test that uses a magnetic field and pulses of radio wave energy to make pictures of the spine. In many cases, an MRI gives different information than an X-ray, an ultrasound, or a CT scan. An MRI also may show problems that can't be seen with other imaging tests. For an MRI, your body is placed inside a...

  • After you have had a seizure, it can be difficult to predict whether you will have more seizures. This makes it hard to decide whether to begin treatment for epilepsy. The first seizure you report may not actually be the first seizure you've had....

  • Guides you through the decision to have imaging tests to evaluate your headaches. Looks at the types of imaging tests used, including CT scan and MRI. Includes interactive tool to help you make your decision.

  • An MRI scan is the best way to locate multiple sclerosis (MS) lesions (also called plaques) in the brain or spinal cord. An MRI scan is abnormal in more than 95% of people recently diagnosed with MS. But abnormal MRI results do not always...

  • An abdominal ultrasound takes pictures of the organs and other structures in your upper belly. It uses sound waves to show images on a screen. Areas that can be checked include the: Abdominal aorta. This large blood vessel passes down the back of the chest and belly. It supplies blood to the lower part of the body...

  • An abdominal X-ray is a picture of structures and organs in the belly (abdomen). This includes the stomach, liver, spleen, and large and small intestines. It also includes the diaphragm, which is the muscle that separates the chest and belly areas. Often two X-rays will be taken from different positions. If the test is...

  • An arthrogram is a test using X-rays to obtain a series of pictures of a joint after a contrast material (such as a dye, water, air, or a combination of these) has been injected into the joint. This allows your doctor to see the soft tissue structures of your joint, such as tendons, ligaments, muscles, cartilage, and...

  • Discusses barium enema, a procedure used to help diagnose problems in the large intestine (colon and rectum). Covers why it's done, how it's done, and how to prepare. Looks at risks. Covers possible results.

  • A bone scan is a test that can find damage to the bones, find cancer that has spread to the bones, and watch problems such as infection and trauma to the bones. A bone scan can often find a problem days to months earlier than a regular X-ray test. During a bone scan, a radioactive substance called a tracer is...

  • An angiogram of the head and neck is an X-ray test that uses a special dye and camera ( fluoroscopy) to take pictures of the blood flow in the blood vessels of the head and neck. An angiogram of the neck (carotid angiogram) can be used to look at the large arteries in the neck that lead to the brain. An angiogram of the...

  • An angiogram is an X-ray test that uses dye and a camera to take pictures of the blood flow in an artery or a vein. An angiogram can be used to look at the arteries or veins in the head, arms, legs, chest, back, or belly. This test is done to look for problems in the arteries or veins. An angiogram is done for many...

  • An angiogram of the lung is an X-ray test that uses a special dye and camera ( fluoroscopy) to take pictures of the blood flow in the blood vessels of the lung. During an angiogram, a thin tube called a catheter is placed into a femoral blood vessel in the groin (femoral vein) or just above the elbow (brachial...

  • A cardiac blood pool scan shows how well your heart is pumping blood to the rest of your body. During this test, a small amount of a radioactive substance called a tracer is injected into a vein. A gamma camera detects the radioactive material as it flows through the heart and lungs. The percentage of blood pumped...

  • Briefly discusses test used to see if a kidney stone or something else is blocking your urinary tract. Covers how it is done and possible results.

  • A chest X-ray is a picture of the chest that shows your heart, lungs, airway, blood vessels, and lymph nodes. A chest X-ray also shows the bones of your spine and chest, including your breastbone, your ribs, your collarbone, and the upper part of your spine. A chest X-ray is the most common imaging test or X-ray used to...

  • A computed tomography (CT) scan uses X-rays to make pictures of the head and face. During the test, you will lie on a table that is attached to the CT scanner, which is a large doughnut-shaped machine. Your head will be positioned inside the scanner. The CT scanner sends X-rays through the head. Each rotation of the...

  • A cystourethrogram is an X-ray test that takes pictures of your bladder and urethra while your bladder is full and while you are urinating. A thin flexible tube ( urinary catheter) is inserted through your urethra into your bladder. A liquid material that shows up well on an X-ray picture ( contrast material) is...

  • Explains what dental X-rays are and why they are done. Covers commonly used types of dental X-rays, including bitewing and panoramic X-rays. Includes info on risks. Also covers what results mean.

  • An echocardiogram (also called an echo) is a type of ultrasound test that uses high-pitched sound waves that are sent through a device called a transducer. The device picks up echoes of the sound waves as they bounce off the different parts of your heart. These echoes are turned into moving pictures of your heart that...

  • Describes extremity X-rays, what they are, and why they are done. Provides tips on how to prepare. Also covers risks. Explains normal and abnormal results, as well as what can affect accuracy of tests.

  • Discusses mammogram, an X-ray test of the breasts used to screen for breast problems. Covers at what ages women should have a mammogram. Discusses how it is done and how to prepare for it. Covers possible results.

  • Discusses test (also called MRI scan) that uses a magnetic field and pulses of radio wave energy to make pictures of organs and structures inside the body. Covers why it is done, how to prepare, and how it is done.

  • A skull X-ray is a series of pictures of the bones of the skull. Skull X-rays have largely been replaced by computed tomography (CT) scans. A skull X-ray may help find head injuries, bone fractures, or abnormal growths or changes in bone structure or size.

  • Spinal X-rays are pictures of the spine. They may be taken to find injuries or diseases that affect the discs or joints in your spine. These problems may include spinal fractures, infections, dislocations, tumors, bone spurs, or disc disease. Spinal X-rays are also done to check the curve of your spine ( scoliosis) or...

  • A gallium scan is a nuclear medicine test that can check for problem areas in certain tissues in your body. A radioactive tracer (tracer) called gallium citrate is injected into a vein in your arm. It moves through your bloodstream and into certain tissues. These tissues include your bones, liver, and intestine, and...

  • Discusses nuclear scanning test done to evaluate gallbladder function. Covers how to prepare for test and how it is done, including use of radioactive tracer substance. Includes info on risks and what test results may mean.

  • An intravenous pyelogram (IVP) is an X-ray test that provides pictures of the kidneys, the bladder, the ureters, and the urethra ( urinary tract). An IVP can show the size, shape, and position of the urinary tract, and it can evaluate the collecting system inside the kidneys. During IVP, a dye called contrast material...

  • Discusses nuclear scan to look at liver and spleen for problems. Explains how to prepare for the test, how it is done, and risks. Discusses results and what affects the tests. Looks at other tests that may be done.

  • A lung scan is a type of nuclear scanning test. It is most often used to find a pulmonary embolism. This is a blood clot that prevents normal blood flow in the lung. Two types of lung scans are usually done together. They are: Ventilation scan. You inhale a radioactive tracer gas or mist. Pictures from this scan...

  • A myelogram uses X-rays and a special dye called contrast material to make pictures of the bones and the fluid-filled space (subarachnoid space) between the bones in your spine (spinal canal). A myelogram may be done to find a tumor, an infection,...

  • A computed tomography (CT) scan uses X-rays to make detailed pictures of structures inside of the body. During the test, you will lie on a table that is attached to the CT scanner, which is a large doughnut-shaped machine. The CT scanner sends X-rays through the body area being studied. Each rotation of the scanner...

  • Discusses nuclear scanning test to check way kidney works or its shape and size. Also called a renal scan. Covers use to check for cancer or how transplanted kidney is working. Explains how camera scans for radiation to make pictures of kidney.

  • A salivary gland scan uses a special camera and a tracer (radioactive chemical) to take pictures of the salivary glands. This can help your doctor find the cause of dry mouth ( xerostomia) or swelling in the salivary glands. During a salivary gland scan, the tracer liquid is put into a vein ( IV) in your arm. The...

  • A testicular scan uses a special camera to take pictures of the testicles after a radioactive tracer builds up in testicular tissues (nuclear medicine test). During a testicular scan, the tracer is injected into a vein in your arm. It travels through your blood to the testicles. Parts of the testicles where the...

  • A thyroid scan uses a radioactive tracer and a special camera to measure how much tracer the thyroid gland absorbs from the blood. The tracer can be swallowed or can be injected into a vein. It travels through your body, giving off radiation signals. The camera "sees" the signals and can measure how much tracer the...

  • Discusses test that uses X-rays to find problems in the esophagus, stomach, and small intestine. Covers why and how it is done. Offers tips on preparing for the test. Covers risks. Looks at results and at what could affect the test.

  • In a technetium-labeled red blood cell bleeding scan, blood is taken from you, and a small amount of radioactive material called technetium is added to the blood. The blood with the technetium is then injected back into your bloodstream. Red blood...

  • A heart catheterization is a procedure used for both diagnosis and treatment of congenital heart defects. As a test, this procedure allows doctors to see how blood flows through the heart chambers and arteries. As a treatment, the doctor can use special tools to fix a heart defect during this procedure. How is it...

  • Guides you through the decision to have an angiogram. Explains why the test is done and what it can show. Discusses why you might or might not want to have the test. Lists risks and benefits. Includes interactive tool to help you decide.

  • A breast ultrasound uses sound waves to make a picture of the tissues inside the breast. A breast ultrasound can show all areas of the breast, including the area closest to the chest wall, which is hard to study with a mammogram. Breast ultrasound does not use X-rays or other potentially harmful types of radiation...

  • A bone density test is a kind of X-ray test. It measures the density of minerals (such as calcium) in your bones. This information helps your doctor estimate the strength of your bones. We all lose some bone mass as we age. Bones naturally become thinner as you grow older. This is because existing bone tissue is...

  • A Doppler ultrasound test uses reflected sound waves to see how blood flows through a blood vessel. It helps doctors assess the blood flow through major arteries and veins, such as those of the arms, legs, and neck. It can show blocked or reduced flow of blood through narrow areas in the major arteries of the neck. This...

  • Fetal ultrasound is a test done during pregnancy that uses reflected sound waves. It produces a picture of the baby (fetus), the organ that supports the fetus ( placenta), and the liquid that surrounds the fetus ( amniotic fluid). The picture is displayed on a TV screen. It may be in black and white or in color. The...

  • Discusses test that uses sound waves to make a picture of organs and structures in the lower belly (pelvis). Covers transabdominal, transrectal, and transvaginal ultrasound. Discusses use to check for different cancers.

  • Covers imaging test to check the thyroid gland and parathyroid glands. Includes info on problems the test checks for, such as lumps in the thyroid gland or enlarged thyroid and parathyroid glands. Covers how it's done. Discusses possible results.

  • Guides through decision to have a diagnostic test like an MRI or arthroscopy done on a meniscus tear. Describes the two tests. Lists the three types of meniscus tears. Covers benefits and risks. Includes an interactive tool to help you make your decision.

  • Single photon emission computed tomography (SPECT) is a nuclear medicine imaging test. It is a type of positron emission tomography, also called a PET scan. Doctors use SPECT to: Diagnose a person who has symptoms of heart disease. Assess your risk of heart attack. Find damaged heart tissue after a heart attack...

  • Routine exams and tests At each prenatal visit, you can expect to be weighed. Your blood pressure will be checked. Your urine may also be checked for bacteria, protein, or sugar. Your doctor or midwife will track your baby's growth and position. To do this, he or she will measure the size of your uterus (fundal height)...

  • Discusses test (also called MRI scan) that uses a magnetic field and pulses of radio wave energy to make pictures of the head. Covers why it is used, including helping to diagnose a stroke or blood vessel problems in the head and looking for tumors or infections.

  • Cranial ultrasound uses reflected sound waves to make pictures of the brain and its inner fluid chambers (ventricles). Cerebrospinal fluid flows through these chambers. This test is most commonly done on babies. Cranial ultrasound for babies Cranial ultrasound can only be done on babies before the bones of the skull...

  • A CT scan uses X-rays to make detailed pictures of the spine and vertebrae. During the test, you will lie on a table that is attached to the CT scanner, which is a large doughnut-shaped machine. The CT scanner sends X-rays through the body. Each rotation of the scanner takes a second and provides a picture of a thin...

  • A facial X-ray is a series of pictures of the bones in the face. One type of facial X-ray (called a paranasal sinus X-ray series) looks at the air-filled cavities (sinuses) around the nose and eyes. A facial X-ray helps find bone fractures, tumors, foreign objects, infections, and abnormal growths or changes in bone...

  • Discusses test (also called MRI scan) that uses a magnetic field and pulses of radio wave energy to make pictures of organs and structures inside the belly. Covers why it is done, how to prepare, and how it is done. Discusses results.

  • Discusses test (also called MRI scan) that uses a magnetic field and pulses of radio wave energy to make pictures of the shoulder. Covers why it is done, such as checking for unexplained shoulder pain or torn tendons. Discusses results.

  • Discusses test (also called MRI scan) that uses a magnetic field and pulses of radio wave energy to make pictures of the knee. Covers why it is used, including to find problems like arthritis, meniscus injury, or damaged cartilage, ligaments, or tendons.

  • Nuclear medicine scans use a special camera (gamma) to take pictures of tissues and organs in the body after a radioactive tracer (radionuclide or radioisotope) is put in a vein in the arm and is absorbed by the tissues and organs. The radioactive...

  • Experts agree that mammograms are the best screening test for people at average risk of breast cancer. But they don't all agree on the age at which screening should start. And they don't agree on whether it's better to be screened every year or every two years. Here are some of the recommendations from experts...

  • Magnetic resonance imaging (MRI) uses a magnetic field and pulses of radio waves to make pictures of the breast. It does not use X-rays. MRI may show problems in the breast that can't be seen on a mammogram, ultrasound, or CT scan. The MRI makes pictures that show your breast's normal structure; tissue damage or...

  • A radioactive iodine uptake (RAIU) test uses a radioactive tracer and a special probe to measure how much tracer the thyroid gland absorbs from the blood. The test can show how much tracer is absorbed by the thyroid gland. The RAIU test often is done along with a thyroid scan, which shows if the tracer is evenly spread...

  • A magnetic resonance cholangiogram (MRC) is a test that can help doctors look for problems in the belly. The image is done from outside the body. No instruments are inserted in the body. Doctors can use MRC to find gallstones before surgery to remove the gallbladder (laparoscopic cholecystectomy). But the test is most...

  • Abdominal aortic aneurysms can be found during an ultrasound screening test. Screening tests help your doctor look for a certain disease or condition before any symptoms appear. Not all doctors agree on who should be screened for abdominal aortic aneurysm. Talk to your doctor about whether the benefits of screening...

  • A testicular ultrasound (sonogram) is a test that uses reflected sound waves to show a picture of the testicles and scrotum. The test can show the long, tightly coiled tube that lies behind each testicle and collects sperm (epididymis). And it can show the tube ( vas deferens) that connects the testicles to the prostate...

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