How to Prepare for Your CT Exam

Computer tomography scan (popularly referred to as CT scan) is a noninvasive diagnostic procedure that involves the use of computer technology together with a combination of X-rays to generate axial or horizontal images (commonly known as slice) of the body. A CT scan generates a more comprehensive image of any section of the body including organs, fats, muscles, bones and blood vessels. It is known to be more precise than the normal X-rays.

CT scans can be used for multiple purposes, but it’s more suited for quick examination of people who are suspected to have internal injuries caused by either car accidents or any other kind of trauma. With a CT scan machine you can literally visualize any part of the body. It is also useful when planning for surgical, radiation, or medical treatment.

When it was first developed, it took a slice at a time and it was pretty slow, especially when compared to today’s CT machines. Unlike the old CT machine, the modern scanners pick more than one slice at any one time (ranges from 4 to 320 slices at a time). In fact, the latest CT scan machine takes a record 640 slices at a time.

After the Medical Imaging Technologist or radiographer has carried the scan, the tiny slices are then combined to create a body part. Once the slices have been fused together, the radiographer can split it into slices in any direction that will make it easy for the radiologist to interpret. Each scan is established precisely for the section of the body of interest and for the disease, injury, or condition that requires investigation

So, What Should You Do Before a CT Scan?

There are a number of things that you will be required to do before you undergo a CT scan. However, the requirements and preparation procedures are dependent on the type of CT scan you’ve been scheduled to undergo. Generally, there are two main types of CT scans i.e. contrast and non-contrast CT scans. Contrast is basically a substance that is either ingested or injected via an intravenous (IV) line to make the tissue or organ being examined appear more visible.

If you have been booked for a CT scan without contrast, you’ll not be required to do much as there is no special preparation as such. A CT scan with contrast, on the other hand, is one that has a number of requirements and requires preparation before the scan.

You may be told to drink some water (around 500ml of water). This helps to keep you hydrated before you take the oral contrast for the scan. Additionally, you may be asked to take an additional half a liter of water as you wait in the waiting room. This is essential as it helps in outlining your bowel and stomach during the scan. Moreover, it makes your bladder full hence making it visible on the scan,

Don’t worry much about what to do before a CT scan since you’ll be given instructions by the hospital before the exam. If you’re admitted (in-patient) in a hospital, the nurses will let you in on the requirements. They’ll also ensure that the necessary preparation is done beforehand.

This then leads us to the next question:

Do You Need to Drink or Eat Before a CT Scan?

Well, it depends on the type of CT scan you’ve been scheduled for. If you are set for a CT scan without contrast, you are allowed to take your medication, eat and drink as you please before the scan. On the other hand, if you are scheduled for a contrast CT scan, you are not permitted to take anything – don’t eat anything for at least 3 to 4 hours prior to the scan. You are, however, allowed to take clear fluids. You can also take your medication as prescribed before the scan.

For abdominal scans, you may be required to drink a specific type of iodinated contrast solution that will give the structure or layout of your intestine. This process also requires fasting. You may be required to drink this solution at different intervals depending on where the CT scan will be done. Normally, one is required to drink part of the solution at least an hour before the exam and the remaining just before going for the scan. Depending on the hospital and the type of scan you’ve been booked for, you may be required to put on the hospital gown to avoid parts of your clothes impeding the scan.

If you are diabetic, it is advisable that you take a light lunch or breakfast three hours before the exam. Regarding medication, your doctor may advise you to stop some of the medication for at least 48 hours.

Why Are You Not Allowed to Eat Before a Contrast CT Scan?

The primary reason why you are not permitted to eat before a CT scan is simply because a mixture of food and contrast may make you nauseated. This may cause you to vomit while lying down which is risky as the vomit may enter your lungs making it difficult for you to breathe. You are, however, allowed to take fluids, even coffee and sport drinks.

What Should You Not Do Before a CT Scan?

As stated earlier, if it is a contrast CT scan, you are not allowed to eat for at least 3 to 4 hours before the scan. You are also not allowed to have metallic items e.g. dentures, jewellery belts and eyeglasses, that may interfere with the scan. You might also need to avoid food containing sugars and some processed foods such as potatoes, legumes, tomatoes, pastas/noodles, crackers, ketchups, chips, ice cream, juices, sauce and gravies, corn and rice cakes.

What Is the Stuff You Drink Before a CT Scan?

As mentioned, there are certain drinks that you will probably have to drink before undergoing a CT scan. Depending on the type of CT scan, you might be required to take a glass of oral contrast. An oral contrast is basically a solution of Gastrografin or barium (diatrizoate sodium liquid or diatrizoate meglumine).

Gastrografin and barium are chemicals that help to make your bowel and stomach images appear more clearer. Barium in particular, has a chalky texture and taste. Once you have drunk the oral contrast, you’ll have to wait for roughly around 60 to 90 minutes for the liquid to move through the digestive system.

Before you undergo a CT scan, it is important that you tell your doctor if you have any allergies to iodine, barium or any other type of contrast dyes.You also need to report to your doctor if you are pregnant or diabetic

Is It OK to Drink Coffee Before a CT Scan?

Yes, you can drink coffee before a CT scan. There is no problem with that. In fact, you are encouraged to drink at least 500mls of water and this may include coffee and tea.

So for coffee lovers, don’t worry – you can still continue to enjoy your coffee.

What to Expect During Your CT Scan

Nowadays, you can have a CT scan either in a hospital or any other outpatient facility. The scan itself is a very simple process and is painless. With the modern CT scan machines, the process can be as quick as 30 minutes.

The scanners are doughnut-like devices that are located on the sides. You’ll be instructed to lie on a narrow automated table that glides through a tunnel-like opening. Pillows and straps may be applied to enable you stay in position for an accurate scan. In the case of a head scan, the table might contain some unique cradle that helps to hold your head in a specific position.

As the table slides into the scanner, the X-ray tubes and detectors rotate around you with each rotation producing multiple images comprising of thin slices of your body. You may hear some whizzing, whirring or buzzing sounds. Don’t panic as that is normal and it’s a sign that the machine is functioning.

During the entire procedure, a technologist – though in a separate room, will be present. The technician can see and hear you can communicate with them via an intercom. The technologist may be asked to hold your breath at some point during the procedure. This helps to prevent blurry images.

After the procedure, you can go on with your usual activities. If you were given some contrast material during the scan, you may be given some special instructions to follow. In some instances, you may be requested to remain at the hospital for a few minutes just to make sure that you don’t have any allergic reaction from the contrast and are not suffering from the after-effects of the procedure. You may also be instructed to drink plenty of water to help your kidney clear the contrast material from your body.

Are There Any Effects From a CT Scan?

Majority of people who undergo a CT scan experience no allergic or any other negative experience from the scan. After the procedure, you can eat or drink as usual.

If you were given an iodinated injection, you may experience some strange taste and a warm sensation, but this goes away after a few minutes. In some rare occasions, some patients may develop an allergic reaction to the iodinated contrast that is usually given on the arm or in the vein at the back of your hands.

It is usually not easy for the radiographer to tell whether or not you are allergic to the iodinated contrast; however, the technicians together with the nurses have been trained to handle the allergies and therefore you have nothing to worry about. It is, however, advisable that you tell your doctor if you have any allergies.

In a world of high CT costs, Princeton Radiology provides an excellent alternative to other area healthcare facilities. Request an appointment today.