| Medical Dictionary |
A Medical Dictionary of Medical Terminology
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Diagnostic imaging lets doctors look inside your body for clues about a medical condition. A variety of machines and techniques can create pictures of the structures and activities inside your body. The type of imaging your doctor uses depends on your symptoms and the part of your body being examined. They include:
Many imaging tests are painless and easy. Some require you to stay still for a long time inside a machine. This can be uncomfortable. Certain tests involve exposure to a small amount of radiation.
For some imaging tests, doctors insert a tiny camera attached to a long, thin tube into your body. This tool is called a scope. The doctor moves it through a body passageway or opening to see inside a particular organ, such as your heart, lungs, or colon. These procedures often require anesthesia.
Computed tomography (CT) is a type of medical imaging test that uses special x-ray equipment to make detailed pictures of the inside of your body.
A CT scan produces cross-sectional pictures, which are like slices of the body. These images show the size and structure of organs, bones, and other tissues. CT images can also be combined to create 3-dimensional (3D) views.
Health care providers use CT scans to diagnose, treat, and monitor many health conditions.
Who needs a CT scan?Your provider may suggest a CT scan for many reasons, including:
CT scans may also be used to find the best place to perform a biopsy or help guide certain treatments. They may also be used to check for internal bleeding or injury after trauma or to evaluate the brain for certain conditions.
How do you prepare for a CT scan?You may be asked not to eat or drink for a few hours before the scan. Ask your provider if there are any special instructions to follow.
For some CT scans, you may receive a contrast material. Contrast helps certain parts of the body show up more clearly on the images. Depending on what area is being examined, contrast material might be given as:
CT scans use ionizing radiation at levels higher than a standard x-ray, but the amount is kept as low as possible. Always tell your provider if you are pregnant or think you may be pregnant.
How is a CT scan done?You may be asked to change clothes and remove jewelry or other items that could interfere with the scan.
During the scan, you lie still on a table. The table slowly passes through the center of a large donut-shaped machine. The x-ray tube rotates around your body to create images.
You may hear whirring sounds during the scan. You may be asked to hold your breath for short periods. The test is painless.
The scan usually takes a few minutes, but some may last up to 30 minutes, depending on the area being scanned.
What should you expect after a CT scan?Most people can return to normal activities right away. If you were given a contrast material, drinking fluids can help your body clear it.
A specialist called a radiologist reviews the images and shares the results with your provider.
NIH: National Cancer Institute
Magnetic resonance imaging (MRI) uses a large magnet and radio waves to look at organs and structures inside your body. Health care professionals use MRI scans to diagnose a variety of conditions, from torn ligaments to tumors. MRIs are very useful for examining the brain and spinal cord.
During the scan, you lie on a table that slides inside a tunnel-shaped machine. Doing the scan can take a long time, and you must stay still. The scan is painless. The MRI machine makes a lot of noise. The technician may offer you earplugs.
Before you get a scan, tell your doctor if you:
You've probably seen your chart at your doctor's office. In fact, you may have charts at several doctors' offices. If you've been in the hospital, you have a chart there, too. These charts are your medical records. They may be on paper or electronic. To keep track of all this information, it's a good idea to keep your own personal health record.
What kind of information would you put in a personal health record? You could start with:
X-rays are a painless medical imaging test. They send a small amount of radiation through your body to create pictures of bones and organs.
X-rays are a type of electromagnetic radiation. They create images in shades of black, white, and gray because different tissues absorb radiation differently. Bones absorb the most radiation and appear white. Fat and other soft tissues absorb less and appear gray. Air absorbs the least radiation, so areas like the lungs appear black.
The image is recorded on film or sent to a computer. Health care providers use x-rays to find health problems and to check how well certain treatments are working.
Who needs an x-ray?X-rays are commonly used to check for fractures (broken bones). They are also used for other purposes. For example, chest x-rays can detect pneumonia. Mammograms use x-rays to look for breast cancer. X-rays are also used as part of other imaging tests, such as CT scans.
How do you prepare for an x-ray?In most cases, little or no preparation is needed. You may be asked to wear a lead apron to protect certain parts of your body. You may also be asked to remove jewelry or other items that could affect the image.
The amount of radiation from an x-ray is small. For example, the radiation from a chest x-ray is about the same as the natural radiation you are exposed to from the environment over about 10 days.
Always tell your provider if you are pregnant or think you may be pregnant.
How is an x-ray done?Depending on the part of your body being examined, you may be asked to stand, sit, or lie down. You will need to stay still for a short time while the image is taken.
What should you expect after an x-ray?After an x-ray, you can return to normal activities right away. A specialist called a radiologist reviews the images and shares the results with your provider.
Your abdomen extends from below your chest to your groin. Some people call it the stomach, but your abdomen contains many other important organs. Pain in the abdomen can come from any one of them. The pain may start somewhere else, such as your chest. Severe pain doesn't always mean a serious problem. Nor does mild pain mean a problem is not serious.
Call your health care provider if mild pain lasts a week or more or if you have pain with other symptoms. Get medical help immediately if:
An abscess is a pocket of pus. You can get an abscess almost anywhere in your body. When an area of your body becomes infected, your body's immune system tries to fight the infection. White blood cells go to the infected area, collect within the damaged tissue, and cause inflammation. During this process, pus forms. Pus is a mixture of living and dead white blood cells, germs, and dead tissue.
Bacteria, viruses, parasites and swallowed objects can all lead to abscesses. Skin abscesses are easy to detect. They are red, raised and painful. Abscesses inside your body may not be obvious and can damage organs, including the brain, lungs and others. Treatments include drainage and antibiotics.
An acoustic neuroma is a benign tumor that develops on the nerve that connects the ear to the brain. The tumor usually grows slowly. As it grows, it presses against the hearing and balance nerves. At first, you may have no symptoms or mild symptoms. They can include:
The tumor can also eventually cause numbness or paralysis of the face. If it grows large enough, it can press against the brain, becoming life-threatening.
Acoustic neuroma can be difficult to diagnose, because the symptoms are similar to those of middle ear problems. Ear exams, hearing tests, and scans can show if you have it.
If the tumor stays small, you may only need to have it checked regularly. If you do need treatment, surgery and radiation are options.
If the tumors affect both hearing nerves, it is often because of a genetic disorder called neurofibromatosis.
NIH: National Institute on Deafness and Communication Disorders
Adhesions are bands of scar-like tissue. Normally, internal tissues and organs have slippery surfaces so they can shift easily as the body moves. Adhesions cause tissues and organs to stick together. They might connect the loops of the intestines to each other, to nearby organs, or to the wall of the abdomen. They can pull sections of the intestines out of place. This may block food from passing through the intestine.
Adhesions can occur anywhere in the body. But they often form after surgery on the abdomen. Almost everyone who has surgery on the abdomen gets adhesions. Some adhesions don't cause any problems. But when they partly or completely block the intestines, they cause symptoms such as:
Adhesions can sometimes cause infertility in women by preventing fertilized eggs from reaching the uterus.
No tests are available to detect adhesions. Doctors usually find them during surgery to diagnose other problems.
Some adhesions go away by themselves. If they partly block your intestines, a diet low in fiber can allow food to move easily through the affected area. If you have a complete intestinal obstruction, it is life-threatening. You should get immediate medical attention and may need surgery.
NIH: National Institute of Diabetes and Digestive and Kidney Diseases
Your adrenal, or suprarenal, glands are located on the top of each kidney. These glands produce hormones that you can't live without, including sex hormones and cortisol, which helps you respond to stress and has many other functions.
A number of disorders can affect the adrenal glands, including tumors. Tumors can be either benign or malignant. Benign tumors aren't cancer. Malignant ones are. Most adrenal gland tumors are benign. They usually do not cause symptoms and may not require treatment. Malignant adrenal gland cancers are uncommon.
Types of tumors include:
Symptoms depend on the type of cancer you have. Treatments may include surgery, chemotherapy, or radiation therapy.