What is a CT Scan?

CT scans combine a series of X-ray images taken from different angles and uses computer processing to create cross-sectional images, or slices, of the bones, blood vessels and soft tissues inside your body.

Each picture created during a CT procedure shows the organs, bones, and other tissues in a thin “slice” of the body. The entire series of pictures produced in CT is like a loaf of sliced bread—you can look at each slice individually (2-dimensional pictures), or you can look at the whole loaf (a 3-dimensional picture). Computer programs are used to create both types of pictures.

CT scan demonstrating views in the Axial (head to toe) plane, Coronal (front to back) plane and Sagittal (side to side) plane

Outside of cancer, CT is widely used to help diagnose circulatory (blood) system diseases and conditions such as coronary artery disease (atherosclerosis), blood vessel aneurysms, and blood clots; spinal conditions; kidney and bladder stones; abscesses; inflammatory diseases, such as ulcerative colitis and sinusitis; and injuries to the head, skeletal system, and internal organs. CT can be a life-saving tool for diagnosing illness and injury.

Within cancer, CT is used to:

  • detect abnormal growths
  • help diagnose the presence of a tumor
  • provide information about the stage of a cancer
  • determine exactly where to perform (i.e., guide) a biopsy procedure
  • guide certain local treatments, such as cryotherapy, radiofrequency ablation, and the implantation of radioactive seeds
  • help plan external-beam radiation therapy or surgery
  • determine whether a cancer is responding to treatment
  • detect recurrence of a tumor

CT abdomen in 3D representation with angled cut through

What is a CTA scan?

A CTA scan (Computed Tomography Angiography) is a type of imaging test used to diagnose and treat medical conditions related to blood vessels, organs or tissues in your body. It combines X-ray images taken from different angles and creates cross-sectional pictures of internal organs and structures such as arteries, veins and tumors that can be viewed in three dimensional space. The CT scanner rotates around you while taking multiple x-rays which are then combined into one detailed image. This helps doctors identify abnormalities or blockages in the blood vessels and plan treatment accordingly.

CTA in 3D view

How to prepare for a CT scan

Preparation for a CT Scan depends on what kind of examination needs to be done. Generally speaking, it’s important to inform your doctor if there is any metal implant in your body before undergoing this procedure. Depending upon the type of scan, a member of staff will inform you if you need to fast prior to the exam. You will also be informed if you need to take oral contrast. Diabetic patients will need to stop metaformin and related medications on day of scan. Additionally, tell your physician about all medications and supplements you take regularly.

How long does a CT scan take?

The appointment lasts between 20-30 minutes depending on the complexity of the patient's condition. This includes both the actual imaging process (5 minutes) as well as preparatory steps such as positioning and injection of contrast dye.

What happens during a CT scan?

During a CT scan, the patient lies flat on their back while X-ray images are taken by a rotating device around them. A special type of dye called a contrast agent may be injected into one of their veins to help highlight blood vessels more clearly in the images. Patients may experience some discomfort when the IV is inserted but should otherwise feel no pain throughout the procedure. Any discomfort includes a whole body warming sensation and a metallic taste which should last around 30 seconds. After all the necessary images have been obtained, the technologist will then review the results with a radiologist who will determine if any further tests need to be done.

What happens after the the scan?

The scanning technician will provide a CD containing your scanned images. Ensure you drink at least 64oz of water after your appointment. The scanned images will also be transmitted to our radiologist who will review and put findings in a medical report that will be provided to your physician. Your physician will review with you the results of the scan.