CT Scan

What is a CT Scan?

CT is short for Computed Tomography. Commonly called CT or CAT scan, Computed Tomography is the preferred modality for many conditions and situations. The Emergency Room (ER) commonly uses CT because the exams are done quickly and can be used to evaluate multiple organ systems at one time. CT works by using X-rays and controlled motion to make a digital representation of the body. That digital representation can then be displayed as images from top to bottom, side to side, or any way in between. CT can be used to show any part of the body – particularly lungs, bones, organs, and blood vessels.

What is Having a CT Scan Like?

CT exams are quick. The screening process generally takes as long as the exam. There are pre-requisite conditions that need to be met (such as fasting, pre-medications, IV access, and lab work) but in general, most CT exams are done within 10-15 minutes. You will be asked to remove any metallic objects in the area of interest, as well as any chewing gum, mints, etc. You will lay on a table (or couch) that moves in and out through a gantry that resembles a doughnut. The table moves in and out of the gantry at a set rate while X-rays are produced to make images. During the imaging process, the X-ray tube will rotate around inside the gantry, at times this will sound similar to a wash machine spinning. The X-rays are used during this rotation to create detailed images through the area of interest. This is painless, but does require the patient to hold very still for the exam. Once the images are taken, the technologist will be in to get any additional info needed to finish the exam. After your exam, you may proceed with your day as normal.

What is CT Contrast?

CT contrast, or IV Contrast/Dye, is natural occurring iodine – the same iodine that is in table salt, just in a single large dose. This contrast allows us to obtain much more information from an examination than not using the contrast because it highlights blood vessels, organs, and potentially masses and bleeding. The contrast gives many people strange sensations, such as warmth, flushing, and even feeling like you’ve went to the bathroom. All these sensations are normal. Some people don’t feel anything at all, and that’s also normal. IV contrast is necessary for many exams, and often we will do multiple scans after giving the contrast to see various organs in more detail. After the exam, IV contrast is filtered out of your body by your kidneys and will leave via urine.

What About Contrast Allergies?

Occasionally, you will hear about reactions with IV contrast. While you can certainly have a reaction to the IV contrast, it’s actually what is called a pseudoallergy. This is because there are no active antigens in the contrast and your body naturally needs iodine to function. There is a link between higher amounts and concentrations causing more pseudoallergic reactions, but these are very rare. With that said, we generally do ask patients that have a history of contrast reactions to pre-medicate before the exam. This involves oral steroids and antihistamines (Benadryl) to stop a potential reaction. If you are concerned you can ask your technologist or doctor.

How about Radiation Risks?

While CT uses traditional X-ray radiation, CT exams are much more detailed than standard X-rays because CT requires a much larger amount of radiation. On its own, this is not a concern as long as the images are medically necessary. However, you do want a facility that uses the lowest doses possible for these exams. AMH uses cutting edge radiation reduction procedures and cooperates with the American College of Radiology to reduce dose with the Dose Index Registry program. That means we track and continually improve our doses on a regular basis to ensure that we use as little as possible to get great images.