A computerized tomography (CT) scan combines a series of X-ray images taken from different angles around your body and uses computer processing to create cross-sectional images (slices) of the bones, blood vessels and soft tissues inside your body. CT scan images provide more-detailed information than plain X-rays do.
A CT scan can be used to visualize nearly all parts of the body and is used to diagnose disease or injury as well as to plan medical, surgical or radiation treatment.
- CT scans can show a tumor’s shape, size, and location. They can even show the blood vessels that feed the tumor – all without having to cut into the patient.
- Doctors often use CT scans to help them guide a needle to remove a small piece of tissue. This is called a CT-guided biopsy.
- By comparing CT scans done over time, doctors can see how a tumor is responding to treatment or find out if the cancer has come back after treatment.
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
- Monitor the effectiveness of certain treatments, such as cancer treatment
- Detect internal injuries and internal bleeding
Note:- Tell your doctor if you're pregnant. Although the radiation from a CT scan is unlikely to injure your baby, your doctor may recommend another type of exam, such as ultrasound or MRI, to avoid exposing your baby to radiation.
Contrast material
A special dye called 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 might be given to you:
- By mouth. If your esophagus or stomach is being scanned, you may need to swallow a liquid that contains contrast material. This drink may taste unpleasant.
- By injection. Contrast agents can be injected through a vein in your arm to help your gallbladder, urinary tract, liver or blood vessels stand out on the images. You may experience a feeling of warmth during the injection or a metallic taste in your mouth.
- By enema. A contrast material may be inserted in your rectum to help visualize your intestines. This procedure can make you feel bloated and uncomfortable.