Computed Tomography also known as CT or CAT scan (Computer Aided Tomography) combines x-rays and computers to image the body. Just about any body part can be imaged (abdomen and pelvis, chest, brain, blood vessels, neck) and typically CT scans are done to look for injuries, fractures, tumors, stones, and other disease. A x-ray unit inside a shallow, donut shaped machine produces x-rays, which are collected on the other side of the machine to create cross-sectional image of the body part being examined.
Sometimes radiographic contrast or "x-ray dye" may be need to better visualize the body part being examined. The dye is injected into a vein in the arm to "highlight" blood vessels and other vascular structures within the body. For CT scan of the abdomen and pelvis, oral contrast called barium may be given at least one hour prior to the scan to highlight the stomach and intestinal tract.
What does the equipment look like?
CT Table and Gantry CT Table and Gantry
Reasons for Having a CT Scan
CT of the Abdomen and Pelvis
A CT scan can evaluate for liver disease, jaundice, abdominal pain, and can determine whether cancer has spread from another part of the body. The scan can look for and bleeding in the liver and/or spleen. CT can evaluate inflammation of the pancreas and gallbladder, look for diverticulitis, polyps, and for abscess or infection. A doctor may order a CT for hematuria (blood in the urine), difficult/painful urination, bloody stools, changes in bowel habits, chronic/acute abdominal pain and/or fever, appendicitis, enlarged lymph nodes, evaluate for aneurysm, evaluate blood vessels of upper/lower extremities and head/neck for narrowing or blockage.
A CT can evaluate for pneumonia, lung nodules and/or masses, evaluate for COPD (chronic obstructive pulmonary disease) such as emphysema, evaluate for aneurysm or stenosis (narrowing), chronic cough, fever, chest pain, to evaluate for blood clots within the blood vessels of the lungs.
CT of the Head and Neck
CT is commonly used to evaluate the brain for stroke and intracranial bleeding (hemorrhage). It can evaluate for brain and neck masses, look at the blood vessels in the brain and neck, and evaluate for skull and cervical (neck) spine fractures.
CT of the Extremities and Spine
CT can be used to evaluate any bony anatomy and look for fracture in just about any part of the body. Scans can be performed from the top of the skull to the base of the feet, including the entire spine and pelvis, the face and any extremities (arms and legs).
CT can also be used to evaluate for disc herniations (slipped and torn discs in the back and neck).
CT guided Biopsy and /or Drainage
A CT scan can be used to guide a needle or catheter to the area of the body being examined. An Interventional Radiologist, who is a specially trained doctor that can accurately obtain a sample of tissue or fluid for laboratory analysis, performs this procedure.
CTA or (Computed Tomography Angiography)
A CT scan performed specifically to evaluate the blood vessels. It is a less invasive alternative to conventional angiography and involves no sedation. It involves to administration of "x-ray dye" through a vein in the arm, and can image to brain, neck, chest, abdomen/pelvis, and extremities.
How do I prepare for a CT exam?
If you are having a CT exam requiring oral and/ or IV contrast please download and fill out our Contrast Media Form A.
What will I experience during and after the procedure?
The CT technologist will explain the procedure, answer any questions you might have. Most CT exams are painless, fast and easy. With spiral CT, the amount of time that the patient needs to lie still is reduced. Though the scanning itself causes no pain, there may be some discomfort from having to remain still for several minutes.
If an intravenous contrast material is used, you will feel a slight pin prick when the needle is inserted into your vein. You may have a warm, flushed sensation during the injection of the contrast materials and a metallic taste in your mouth that lasts for a few minutes. Occasionally, a patient will develop itching and hives, which can be relieved with medication. If you become light-headed or experience difficulty breathing, you should notify the technologist or nurse, as it may indicate a more severe allergic reaction.
When you enter the CT scanner, special lights may be used to ensure that you are properly positioned. With modern CT scanners, you will hear only slight buzzing, clicking and whirring sounds as the CT scanner revolves around you during the imaging process.
You will be alone in the exam room during the CT scan, however, the technologist will be able to see, hear and speak with you at all times. If at any time, you experience any discomfort, please tell the technologist immediately.
With pediatric patients, a parent may be allowed in the room but will be required to wear a lead apron to prevent radiation exposure.
After a CT exam, you can return to your normal activities. If you received a contrast material, you may be given special instructions.
Who interprets the results and how do I get them?
A radiologist, a physician specifically trained to supervise and interpret radiology examinations, will analyze the images and send a signed report to your primary care or referring physician, who will share the results with you. In some cases the radiologist may discuss preliminary results with you at the conclusion of your examination