Computed Tomography (CT), also known as a “CAT Scan” is a medical diagnostic tool that allows the visualization of internal structures within the human body. This aids physicians in diagnosing disease, viewing internal abnormalities and assessing the extent of trauma damage.
During the typical CT procedure, the patient is placed on a table. A contrast agent (iodine-based dye, or oral contrast) may be administered prior to the CT scan to allow organs and structures to be seen more easily. The table then moves the patient through a donut-shaped device, which houses an X-ray tube and detector. For each image acquired the X-ray tube rotates around the patient and the X-rays pass through the patient to the detector and thousands of X-ray measurements are acquired. The computer then processes this information and displays the corresponding images on a computer screen. (See Figure 1)
Sometimes CT imaging is compared to looking into a loaf of bread by cutting it into thin slices. (See Figure 2). For this reason, the word ‘slice’ is often used to describe a view of the patient anatomy. This procedure usually takes 15-30 minutes to perform.
CT scans are often used to examine structures in the abdomen and pelvis. They are a diagnostic tool used to detect and diagnose: a recurrent urinary tract infection, sources of blood in the urine (Hematuria), kidney stones, renal cysts and masses. Moreover, it can help rule out prostate, bladder and renal cancers.
Benefits of a CT scan include:
- CT scanning is painless, noninvasive and accurate
- A major advantage of CT is its ability to image bone, soft tissue and blood vessels all at the same time
- Unlike conventional X-rays, CT scanning provides very detailed images of many types of tissue
- CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems
Risk of a CT scan includes:
- There is a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk.
- The risk of serious allergic reaction to contrast materials that contain iodine is extremely rare, and radiology departments are well-equipped to deal with them.