Holston Medical Group

CT Scan

What is a CT Scan?

A CT scan (CAT scan) is a diagnostic test physicians use to view organs, blood vessels, and bones inside the body. The images are produced using an X-ray tube and computer technology. The scan creates images similar to slices of a loaf of bread, allowing doctors to examine the body layer by layer.

What Can You Expect During the CT Scan?

Depending on the type of CT scan, you may be asked to drink an oral contrast solution or receive IV contrast during the exam. The CT scanner is shaped like a doughnut rather than a tube. Most exams take about 30 minutes to complete.

Your results are typically available within one to two days after your exam. No special precautions are required afterward, and you may drive normally following the test.

For Your Personal Safety

  • All patients age 60 or older having an exam that requires intravenous contrast will need laboratory testing, including BUN, Creatinine, and renal function tests.
  • All diabetic patients receiving intravenous contrast who take Glucophage, Glucovance, Metformin, Metaglip, or Avandamet will receive special instructions. These medications cannot be taken for 48 hours after the exam. A BUN and Creatinine test must be completed before medications can be resumed.
  • All patients with allergies to iodine or seafood must be pre-medicated. Please contact the CT Department for a prescription. Patients with known severe allergic reactions (anaphylaxis) will not be given IV contrast.

Instructions for You

CT scans may be performed at one of our diagnostic centers:

Please confirm your appointment location on the physician’s order. The following instructions are organized by procedure. Locate your procedure below and follow the listed preparation guidelines.

Virtual Colonoscopy

Before your exam, bring your doctor’s order to the Radiology Department to pick up a preparation kit. Follow the 24-hour preparation instructions.

  • You will change into a hospital gown when you arrive.
  • A small catheter is inserted into the rectum and air is used to outline the bowel.
  • Scans are completed while lying on your back and then on your stomach.
  • The procedure takes approximately 15–20 minutes.
  • No injections are required for this procedure.

CT Angiograms

  • Do not eat or drink for 6 hours before the exam.
  • Medications may be taken with small sips of water.
  • No oral contrast is required.
  • The exam typically takes about 30 minutes.

Cardiac Scoring

  • EKG leads will be placed on your chest to monitor heart activity.
  • The scanner captures images through the heart.
  • Images are processed to determine if calcium is present in the cardiac vessels.
  • No preparation is required.
  • The exam typically takes about 20 minutes.

CT Brain with and without Contrast

  • No food or drink for 6 hours before the exam.
  • Medications may be taken with small sips of water.
  • The exam takes about 25 minutes.

CT Brain without IV Contrast

  • You may eat and drink normally before the exam.
  • The exam takes about 15 minutes.

CT Abdomen and Pelvis with IV and Oral Contrast

  • Bring your doctor’s order and pick up oral contrast from the Radiology Department one to two days before your exam.
  • BUN and Creatinine lab work may be required depending on patient criteria.
  • Refrigerating the Readi-Cat contrast before drinking is recommended.
  • For morning appointments: drink one bottle at bedtime the night before the exam and the second bottle 45 minutes before the appointment.
  • For afternoon appointments: you may have a light breakfast by 6 am. Drink one bottle three hours before the appointment and the second bottle one hour before the appointment.
  • Medications may be taken with small sips of water.
  • The exam typically takes about 30 minutes.

CT Helical Scan for Renal Stone

  • You may eat or drink normally before the exam.
  • The exam takes about 20 minutes.

CT Chest with IV Contrast

  • No food or drink for 6 hours before the exam.
  • Medications may be taken with small sips of water.
  • The exam takes about 25 minutes.

CT Chest without IV Contrast or High-Resolution Scan

  • You may eat or drink normally before the exam.
  • The exam takes about 20 minutes.

CT Helical Chest for Pulmonary Embolus

  • No food or drink for 6 hours before the exam.
  • Medications may be taken with small sips of water.
  • The exam takes about 25 minutes.

CT Extremities (Without IV Contrast)

  • You may eat or drink normally before the exam.
  • Please bring any X-rays previously taken at your physician’s office.
  • The exam takes about 30 minutes.

CT Maxillofacial and Soft Tissue of the Neck with IV Contrast

  • No food or drink for 6 hours before the exam.
  • Medications may be taken with small sips of water.
  • The exam takes about 25 minutes.

CT Spine

  • You may eat or drink normally before the exam.
  • The exam takes about 25 minutes.

After Your Test

You may resume normal activities after your exam. If oral or IV contrast was used, drink additional fluids to help your body clear the contrast material.

If you experience discomfort after your exam, contact your ordering provider or the Outpatient Diagnostic Center.

If extravasation occurs (leakage of contrast from the vein into surrounding tissue), cold compresses will be applied immediately. Acetaminophen, ibuprofen, or aspirin may be taken for discomfort. Hot compresses and elevation of the affected area may also help.

If symptoms persist longer than 48 hours, contact your ordering provider or the Outpatient Diagnostic Center.