CT Scan

What Is a CT Scan?

Computed tomography, more commonly called a CT scan, is an imaging test. A CT scan uses X-ray techniques to take a series of images from different angles and then combines the images to create a three-dimensional view of your body.

Compared with X-rays, CT scans create cross-sectional images or slices, which provide more detailed information. Often, a chest CT scan is ordered by a healthcare provider after noticing something abnormal in an X-ray. Although the CT scan cannot give a diagnosis, it is helpful in the evaluation of lung diseases and conditions such as pneumonia, cancer, blood clots or damage caused by smoking.

There are different types of chest CT scans. A low dose CT (LDCT) scan is used to screen for lung cancer. If your healthcare provider suspects you may have interstitial lung disease, a high-resolution CT (HRCT) scan provides a detailed picture of your lung’s tissues, airways and air sacs. A CT scan with contrast may be ordered to help your healthcare provider evaluate for blood clots in certain diseases such as a pulmonary embolism.

What Should I Expect from a CT Scan?

A CT technician will instruct you to lie flat on the CT scan table, which moves quickly through a donut-shaped device called a scanner. You will be asked to remain still and hold your breath for a few seconds. While this may seem similar to an MRI, a CT scanner is open, less noisy and takes much less time.

Depending on what part of your body the scan is needed for, you may need to remove some of your clothing and wear a gown, and take off your glasses, and any metal objects. If you think you might be pregnant, make sure to tell your healthcare provider and technician.

If your CT scan is ordered with contrast, you will receive an intravenous (IV) injection, during which you may feel a temporary warm feeling throughout your body. You may be given specific instructions prior to the scan that include not eating or drinking anything at least two hours prior to your contrast scan and also alert your healthcare provider or technician if you have kidney issues and/or allergies to medications or food, particularly iodine.

I Had My CT Scan; Now What?

After your CT scan, you are able to return to your regular activities. A radiologist will analyze the images and create a report that is shared with your healthcare provider. Schedule a follow-up appointment with your healthcare provider to discuss the results, which are typically ready within a few days. Your provider will review the report and images, and discuss and recommend next steps, if any. You may need to repeat the CT scan within a specific time frame; however, it is possible you will be asked to go for additional testing or a procedure such as a biopsy. You can always ask for a copy of your CT scan images for your own records.

What Are the Risks of a CT Scan?

The most significant risk of CT scans is radiation exposure. Discuss this with your healthcare provider, but often the small risks of this level of radiation are offset by the benefit of the information obtained by the scan.

If your provider ordered a CT scan with contrast, alert your healthcare provider and technician if you have an allergy to iodine or IV contrast because you may need to take medications before the scan. This type of CT scan can affect your kidney function, so your healthcare provider will conduct a blood test prior to scheduling the test.