|What Is A CT Scan?
A CT scan (computed tomography) is also called a computed axial tomography (CAT scan). It is a non-invasive test that provides images of inside the body. The CT scanner is a sophisticated X-ray machine that has greatly improved the diagnosis of many conditions since its introduction in the 1970s. Unlike a regular X-ray which only shows a few levels of tissues, the CT scan detects hundreds of levels of density.
CT may be used to detect:
• Cancer. It has revolutionized the detection of cancer and slow growing tumors.
• Broken bones and fractures.
• Heart disease.
• Blood clots.
• Internal bleeding.
While the CT scan has many uses, it is particularly suited to rapid examination of people with internal injuries after accidents. It may also be used to guide surgical procedures, biopsies and radiation therapy.
How Is It Performed?
During a CT scan you are placed on a table which is attached to a doughnut-shaped machine. Straps or pillows may be used to keep you still and comfortable.
If contrast dye is used:
Occasionally a CT contrast dye is required for some examinations. This dye is either injected into the bloodstream or you will need to drink it. It enhances the appearance of blood vessels, inflammation and tumors. If you are having dye, you may be asked to avoid eating or drinking for a few hours before your scan. If the dye is to be injected, a needle will be inserted into your arm before the scan. A warm fluid may be passed through it, to keep the needle from blocking.
The dye can:
• Cause in a metal taste in your mouth.
• Give the sensation that you have wet your pants, but you have not.
• Give you a stinging or a warm flushing feeling for a few minutes.
While you lie still on the table, the machine rotates around your body taking x-ray images. Those images appear as cross-sectional slices of the body on a computer screen. The slices can be stacked together to create a 3D image of the body. The scanner is operated by staff in an adjoining room who will view you through a glass screen. The procedure only takes a few minutes; modern scanners only require 30 to 60 seconds to scan a portion of the body.
What Are The Pros And Cons?
Advantages Of CT Scans
• It can be used to look inside your body instead of using surgery.
• It is cheaper than an MRI scan.
• It is faster and less claustrophobic (because it is less enclosed) than an MRI scan.
• It is painless and highly accurate.
Disadvantages Of CT Scans
• The patient is exposed to radiation, greater than that of a traditional X-ray. Exposure however is not known to pose any immediate or long-term health risk.
• Is cannot be used on pregnant women because of the radiation.
• You may have an allergic reaction to the contrast dye resulting in nausea, vomiting, sneezing and hives.
What Is The Recovery Period?
You will be able to leave hospital soon after the scan is finished and resume normal activities. If you received dye, it will pass out of your body in your urine. You won't notice the dye because it is colorless. You will need to drink plenty of water to help you get rid of it.
CT scans of certain parts of the body may require special preparation:
Abdominal CT Scan
If you are having an abdominal CT scan you may be asked:
• To avoid eating or drinking after midnight before the scan.
• To drink a contrast medium a few hours before the scan, and again in the X-ray department.
• A contrast dye may be injected into you, instead of, or in addition to the drink.
Chest CT Scan
Some thoracic (chest) scans require an injection of contrast dye beforehand. This helps show up areas of tissue near the areas of cancer. It will help determine if cancer surgery will remove all of the cancer or not.
Pelvic CT Scan
• Be asked to avoid eating or drinking for a period of time before the scan.
• Be given a contrast dye injection before the scan.
• Be given another injection to slow down the normal movement of your bowels (peristalsis) before the scan. This movement can make images less clear.
A virtual colonoscopy is a CT scan of the colon (you will be scanned once on your back and once on your front). Instead of having a tube with a camera inserted into your colon (a traditional colonoscopy), a CT scan will be used to look inside your bowels. If you are having this procedure, you will need to take laxatives and a special liquid with your meals for 2 days beforehand. You will also need to eat a special diet. The purpose is to empty your bowels of feces so that they can be viewed more easily. Just before the scan you will receive one injection of contrast dye, and one injection to slow down your normal bowel movements. A tube will be inserted into your rectum to blow air into your bowels. This will inflate them, making it easier for the radiographer to see more clearly. It can cause farting noises, so try not to be embarrassed. The staff are well used to it!
When Will I Get My Results?
You are unlikely to know the results of your scan straight away. The images will need to be studied by the radiologist and possibly shared with other specialists. The radiologist will discuss the results with the doctor who arranged your scan, who will then pass the results on to you. This may take about a week, unless the results are needed urgently.
How Much Does A CT Cost?
A CT scan can vary in cost, from $600 to $3,000. In most instances there is nothing different about the procedure being offered. Different centers charge different prices, so it is important to shop around. Most insurance companies, including Medicare, will reimburse the cost of getting a CT scan.