What is CT SCAN?

What is CT or Cat Scan?

The CT, or computed tomography, scanner operated by rotating an x-ray tube around your body while measuring the constantly changing absorption of the x-ray beam by different tissues in your body. The information is then fed into a computer which produces a reconstructed image of a thin cross section or "slice" of the body. Because the scanner is very sensitive, small differences in absorption of the beam by various body tissues are recorded sharper and clearer than even the best x-ray.

You may be startled by the size and shape of the scanner. Remember nothing touches you, so it will not hurt. You will be asked to lie on the table, usually on your back, and usually with your arms over your head. The moveable table will raise, lower and move in and out of the scanner.

It is extremely important that you do not move during the entire procedure, which lasts from 15 minutes to an hour depending on the examination. The radiologist will study the final images and report the findings to your physician, who will in turn discuss the results with you.

What is a CT scan used for?

A CT scan has many uses because of the improved image quality and ability to capture more data. Some of the most common uses include:

• Diagnose cancer
• Plan surgery
• Plan and guide radiation treatments for tumors
• Diagnose spinal problems
• Identify injuries to the liver, spleen, kidneys, brain and other internal organs
• Diagnose issues with bone structure

How to Prepare for CT?

Head CT:

Your head will be placed in a holder with a strap across your forehead. Images will be taken. The examination will take from 15 - 30 minutes. No prior preparation is required. Sometimes intravenous contrast is required, which will be given in a vein in the arm or hand.

Chest CT:

Most chest CT scans are performed with an IV contrast and prior preparation is not necessary. You will be lying on your back with your arms above your head. The technologist will instruct you to hold your breath for each exposure. The examination should take from 20 - 30 minutes.

Abdomen and/or Pelvis CT:

Most CT scans of the abdomen and/or pelvis require preparation prior to the study. Usually you will be asked to skip the meal immediately prior to your exam.

For an abdomen CT, you will be given a bottle of contrast material that outlines the intestines on the image and another bottle just prior to getting on the table for your exam. For an abdomen and pelvis or just a pelvis CT, you will be asked to arrive one hour prior to exam time. You will be given a bottle of contrast material to drink while you are registering and then you will be given a bottle to drink when you arrive at the scanner and asked to wait approximately 45 minutes. For an abdomen and pelvis CT, you will be asked to drink one more bottle of contrast material just prior to getting on the exam table. Most CT scans of the abdomen require an IV contrast injection in the hand or arm. You will be positioned on your back on the scan table with your arms over our head. You will be instructed by the technologist to hold your breath for each image taken. A scan of the abdomen and pelvis should take approximately 34 - 45 minutes.

There are a few things to bear in mind when preparing for your exam, including:

• Bring a copy of your order for the procedure from your referring healthcare provider if given one, your insurance cards and photo identification
• On the day of the exam, wear comfortable, loose-fitting clothing
• Avoid metal zippers, hair pins, jewelry or clothing with snaps
• Drink plenty of clear liquids, but do not eat anything solid for 3 hours prior to the examination
• Patients who are scheduled for abdominal and/or pelvic exams should arrive 30 minutes prior to the exam time. You will be given oral contrast to drink that helps better visualize the stomach and intestines.
• Patients may take their usual medications prior to exam
• Always inform the technologist or radiologist if you are pregnant or could be pregnant

What to Expect during a CT Scan?

A CT exam takes usually around ten to fifteen minutes from the time you get on the table. Your technologist will ask you to lay on the CT table and based on your study, you will be positioned accordingly. While you are in the room alone, the technologist can see, hear and speak with you the entire time. 

When your CT examination is done, you may resume your normal daily activities unless your healthcare provider instructs you otherwise. Your images will be sent to one of our board-certified radiologists for interpretation and a report will be sent to your provider.

What if I am Claustrophobic?

Patients who are claustrophobic may feel a “closed in” feeling during the CT scan if your head is going first into the gantry. If this is a concern, please let us know prior to your appointment if you think you will require sedation. Your healthcare provider may prescribe something for the claustrophobia to be taken prior to your appointment.

What if I require contrast?

In CT some of the procedures require a special dye, often called “contrast”. Contrast is used to provide better diagnostic quality images. If you are given contrast, you may be asked not to eat or drink anything for 3-4 hours prior to the exam. Contrast injections require your technologist to start an IV prior to exam. Patients sometimes report a metallic taste in the mouth, a warm flushing sensation and/or nausea. These sensations are completely normal and generally go away within a few minutes. Typically, contrast does not cause symptoms; however, some mild symptoms you may experience include nausea, headache or itching. Other side effects are rare; however, if you experience any severe symptoms, inform your technologist immediately.