Computed tomography, or CT, is a safe, painless procedure that uses X-ray and computer equipment to create cross-sectional images of a patient’s body structures. Formerly called a CAT scan, CT imaging allows physicians to examine soft tissue, bones, muscle, internal organs, and blood vessels.
Make an appointment
Call us at 925-467-1400 to schedule an appointment for a CT exam.
What are some common uses of CT?
CT exams are often used for:
- Planning of radiation treatment for tumors
- Cancer staging
- Planning surgery
- Fracture assessment
- Identifying injuries to internal organs, such as the liver or spine
How should I prepare for a CT exam?
Your preparation will depend upon the area of your body being examined:
- Abdomen: Nothing to eat or drink four hours before your exam. You will drink one bottle of contrast one hour prior to your exam.
- Exceptions: There are a few exceptions. You may be given different instructions at the time of scheduling.
- Abdomen/pelvis: Nothing to eat or drink four hours before your exam. You will drink two bottles of contrast prior to your exam. The first bottle of contrast should be taken four hours prior and the second bottle one hour prior to your exam.
- Exceptions: There are a few exceptions. You may be given different instructions at the time of scheduling.
- Brain: Most brain or head CTs require no preparation.
- Exceptions: Scans for tumors require you to avoid food and only consume clear liquids within four hours of your exam.
- Chest: Nothing to eat or drink four hours before your exam.
- Exceptions: Scans for nodules do not require preparation.
- Liver: Nothing to eat or drink four hours before your exam. You will need to drink one bottle of contrast one hour prior to your exam.
- Neck: Nothing to eat or drink four hours before your exam.
- Urogram: Nothing to eat four hours before your exam. Drink 32 ounces of water two hours prior to your exam.
- Extremities, facial bone, and spine: No preparation required.
- CT angiogram (CTA): Nothing to eat or drink four hours before your exam.
Depending on the focus on your CT scan, we may use a contrast material to enhance the visibility of certain tissues or blood vessels. Before receiving the contrast material, please tell the radiologist or technologist if you have:
- Any allergies, especially to medications or iodine
- Any history of diabetes, asthma, kidney problems, or heart or thyroid conditions. These may indicate a higher risk of reaction to the contrast material or potential problems with eliminating the material from your system after the exam.
IV contrast patients: A 12-hour allergy prep is required if you are allergic to iodine. Please be sure to tell us if you are allergic to iodine when scheduling your appointment.
Learn more about preparing for your visit.
What should I expect during this exam?
CT exams usually take between five minutes and half an hour, depending on the area of the body being examined.
Your CT exam at Pleasanton Diagnostic Imaging will follow these steps:
- Our technologist will position you on the CT table, using pillows to help keep you still and comfortable.
- The technologist will leave the room for your exam but will communicate with you throughout using an intercom.
- During the scan, the table will move slowly into place within the CT scanner, while an X-ray tube rotates around you, taking images from different angles. Depending on the area of the body being examined, you may or may not be able to feel the motion. You may also hear buzzing and clicking noises.
What will I experience during this exam?
CT scans are completely painless. Depending on the type of scan needed, your appointment preparation may differ.
If your exam requires the use of a contrast material, your technologist will administer the material through an IV or orally.
- IV injection: The technologist may inject a contrast material into a vein to accentuate the difference between normal and abnormal tissue in organs, such as the liver or spleen, and to better define the blood vessels and kidneys. Following an IV contrast injection, you may feel flushed and have a metallic taste in your mouth, which should pass in a minute or two. In very rare cases, you may experience a mild allergic reaction. We have a physician on staff at all times during injections.
- Oral contrast: We may ask you to drink contrast material, which will allow the radiologist to better see your stomach, small bowel and colon. The oral contrast has a fruity flavor and most patients state the taste is tolerable.