A CT scan provides more information than some other imaging tests without the need for invasive techniques.
For example, it can sometimes be used to complete abiopsy.
This article explains how a CT scan works, why you might need one, and how to prepare.
Verywell / Emily Roberts
Verywell / Emily Roberts
What Is a CT Scan?
What Can CT Scans Detect?
CT Scan vs. MRI
CT scans are fast, widely available, and versatile.
What Is a CT Scan With Contrast?
Most are iodine-based and are injected intravenously (into a vein) before the scan.
Those with a known allergy to a radiocontrast agent should be pre-treated with antihistamines and steroids before receiving contrast.
What Is the Procedure for a CT Scan?
A CT scan is generally quick and painless.
Knowing what to expect during the procedure can help make the process as smooth as possible.
Your healthcare provider will provide specific instructions based on the aims of the test.
Location
The test is typically conducted in a hospital or an independent radiology facility.
A series of X-ray emitters and detectors are in the tunnel’s center (gantry).
These are far less claustrophobic and loud compared to older systems.
The radiographer will conduct the CT scan from a radiation-safe control room adjacent to the scanning room.
How Do I Prepare for a CT Scan?
How long does a CT scan take?
From arrival to completion, the appointment should take around one to two hours.
The scan itself without a contrast agent should take around three to five minutes to perform.
How Much Does a CT Scan Cost?
A more extensive evaluation with a contrast agent may be as high as $5,000.
As a rule, CT scans will require some form of insurance pre-authorization.
Your healthcare provider can submit this request on your behalf.
If approved, be sure to find out what yourout-of-pocket expenseswill be.
If you are uninsured or underinsured, shop around for the best prices.
By and large, hospital radiology units are more expensive than independent ones.
you’ve got the option to also ask if the lab offers flexible payment options.
If you are uninsured, ask if they have a patient assistance program with a tiered price structure.
You will then be led to a changing room to change out of your clothes.
At first, the motorized table will move in and out of the scanner quickly.
You will also see light lines projected onto your body to ensure you are in the correct position.
From there on, the table will move slowly through the scanner.
The gantry will spin around you as the X-ray emitters produce an array of beams.
The beams will pass through your body and be received by corresponding detectors.
During each scan, remember to remain still.
In some cases, you may be asked to hold your breath.
Your position may also be altered to obtain different views.
Unlike CT scanners of old, newer units only emit slight buzzing, whirring, or clicking sounds.
You will feel no pain from the scan.
There is no problem with stopping the test momentarily.
In some cases, the technician may be able to make you more comfortable without obstructing the imaging.
A computer will then translate the signals into a series of cross-sectional (tomographic) images called slices.
The two-dimensional slices can be converted into the final 3D image using geometric digital processing.
Post-Test
The radiographer will double-check once the scans are completed to ensure the images are clearly visualized.
you’re able to usually drive yourself home or to work.
Much of the solution will be excreted in the urine, so drink plenty of fluids.
Call a healthcare provider if you dont have a bowel movement after two days.
In addition to the images, theradiologistwill prepare a detailed report outlining the normal and abnormal findings.
This is especially true with abnormal growths, lesions, and tumors.
In some cases, no problem may be found.
This doesn’t mean that you are necessarily in the clear.
It simply indicates that nothing was detected based on the limitations of the CT technology.
Based on the results, your healthcare provider may offer a treatment plan or recommend further testing.
A CT scan is fast and accurate.
What Are the Risks of a CT Scan?
However, studies have found no clear association between medical radiation and cancer risk in children.
When used appropriately, the benefits of a CT scan will almost always outweigh the possible risks.
Allergic Reactions
Life-threatening allergic reactionsknown asanaphylaxisto CT contrast is extremely rare.
If not treated immediately, anaphylaxis can lead to seizures, coma,shock, and even death.
Can I Have a CT Scan If I’m Pregnant?
CT scans may pose some risks if you are pregnant.
If you suspect you may be pregnant or have been trying to get pregnant, advise your healthcare provider.
Generally speaking, the risk to your fetus is negligible if the abdomen or pelvis is not being scanned.
If the CT scan involves the abdomen or pelvis, the risk to your baby is still considered minor.
Similarly, oral and rectal contrast agents are not absorbed in the bloodstream and cannot harm the fetus.
(In such cases, pumping a couple of days' supply beforehand can tide you over.)
Can I Have a CT Scan if Im Claustrophobic?
Summary
CT scans are generally safe, well-tolerated, and helpful for diagnosing various conditions.
They can be performed quickly, and thus are an invaluable tool for diagnosing time-sensitive injuries and diseases.
Johns Hopkins Medicine.Computed tomography (CT) scan.
National Cancer Institute.Computed tomography (CT) scans and cancer.
2022;8(3):1401-1412. doi:10.3390/tomography8030113
