CAT Scan 101. How Long Should You Expect to Stay in the Machine?


A CT scan, also known as computed tomography scan, is a medical imaging procedure that uses computer-processed combinations of multiple X-ray images taken from different angles to produce cross-sectional (tomographic) images (virtual “slices”) of specific areas of the body. CT scans allow doctors to see the inside of the body in detail.

The CT scan process involves lying on a table that slides into a tunnel-like machine. During the scan, X-ray beams pass through the body, taking images that a computer converts into detailed 2D or 3D pictures. The actual scan typically takes 5-10 minutes, with more time needed for setup beforehand and after for removal of any contrast dye. Patients are asked to lie still but can breathe normally during the scan. The technician operates the CT scanner and observes the procedure from a closed-off area nearby. Overall, the appointment lasts approximately 30 minutes to an hour.

Preparing for the Scan

Arriving early and preparing properly for your CAT scan appointment ensures the test goes smoothly. Most facilities recommend arriving at least 15-30 minutes before your scheduled scan time.

When you arrive, you will likely need to change into a hospital gown to remove any clothing with metal items such as zippers, snaps, or buttons that could interfere with imaging. The technician may ask you to remove jewelry, glasses, hearing aids, hair pins, and removable dental work as well.

It is important to leave valuable personal belongings at home or with a loved one. Items like wallets, phones, keys and jewelry will need to be stored in a locker during the scan. By arriving early and allowing extra time to change and store your belongings, you can avoid delaying the start of your scan.

Hospitals advise wearing comfortable clothing without metal fasteners when possible, to simplify the change into a gown. Arriving prepared helps the scanning process go smoothly and efficiently.

Length of Scan

The actual CAT scan procedure is very quick, usually lasting about 10-15 minutes (Source). The scan itself involves lying still on a table that moves in and out of the CT scanner, which rotates around the body and takes multiple X-ray images. Since the scan is fast, you only need to hold still for 10-15 minutes while the images are acquired.

However, the total appointment time is longer than just the scan itself. Before the scan, you will need time to change into a hospital gown, receive instructions on how to position yourself, and possibly have an IV line placed if contrast material will be used. Afterwards, you will need time to change back into your clothes before you can leave. So the complete appointment may last 30 minutes or longer, even though the actual scan is less than 15 minutes.

During the Scan

During the CT scan, you will lie still on a table that slides into the scanning tunnel. The scanner is a large, doughnut-shaped machine that rotates around your body as you move through it, allowing it to capture images from different angles.

It is very important to lie completely still throughout the entire scan and follow any breathing instructions from the technician. Even slight movements can cause blurring in the images. You may be asked to hold your breath for several seconds during the test.

The scanning table will slide back and forth through the large opening in the machine as the X-ray beam rotates around your body. With each pass, the X-ray beam captures thin slices of images that will be compiled together by a computer to create cross-sectional views of the inside of your body.

You may hear whirring or clicking noises from the machine during the scan. Some facilities allow you to listen to music during the exam to help you relax.

According to the Mayo Clinic, a CT scan of the head takes only a few seconds. Scans of other larger areas, like the abdomen or pelvis, could take 10 to 30 minutes (source). The radiology technician will inform you how long your scan will take before beginning.

After the Scan

Once the scan is complete, the technician will ensure they have all of the required images and you are free to get dressed. The technician will let you know that the scan is finished and you can get off the table when ready. There is no recovery or resting period required after a CT scan. As soon as you are dressed, you are free to leave the scanning area and go about your day (Source).

The entire CT scanning process from arrival to leaving typically takes between 15 minutes to an hour. This includes time for preparation, the scan itself, and getting dressed afterwards before leaving. The actual scan time is usually very quick, often only a matter of minutes. The preparation and waiting periods before and after the scan make up the bulk of the time spent in the radiology department (Source).

Getting Scan Results

Once the scan is complete, the images are sent to a radiologist, who is a physician specializing in analyzing medical images. The radiologist will carefully examine the CAT scan images, looking for any concerning findings. They analyze the images for any abnormalities, masses, fractures, bleeding, or other issues.

After thoroughly evaluating the images, the radiologist will dictate a report of their findings. This report is sent electronically to the ordering physician, usually within 24-48 hours after the scan is performed. However, results can take longer if the scan is done over a weekend or holiday.

Once the ordering doctor receives the radiologist’s report, they will contact the patient to discuss the results. If any issues were found on the scan, the doctor will explain what was seen and recommend next steps, such as additional imaging, specialist referral, or treatment. They can also explain the results if the scan was normal. Getting results directly from one’s physician, who can explain them in depth, helps patients understand the meaning of the test and what will happen next.

Waiting for results can cause anxiety for many patients. However, direct communication from one’s doctor can provide reassurance and help patients understand their health situation.

Factors Affecting Length

The length of time it takes to complete a CT scan can vary based on several factors:

Type of scan – The part of the body being scanned and the level of detail needed affects scan time. A scan of the head or an extremity usually takes less time than a scan of larger areas like the abdomen or chest.

Part of body being scanned – A CT scan focused on a small area like the sinuses may take less than 5 minutes, while a full body scan can take over an hour to image everything.

Patient mobility issues – Patients who have difficulty staying still or holding their breath for the short intervals required may need more time. Technologists can provide coaching and support.

According to WebMD, a typical CT scan takes between 5-30 minutes depending on what’s being imaged. More detailed scans like CT angiograms take longer.

Anxiety and Coping

Many patients feel anxious or nervous before getting a CAT scan, especially if they are claustrophobic or have a fear of enclosed spaces. There are several tips that can help manage anxiety and make the scan process easier:

Try closing your eyes and doing breathing exercises during the scan to relax. Focus on taking slow, deep breaths to maintain a calm state of mind. You can also listen to relaxing music through headphones if provided.

Inform the technician beforehand if you have claustrophobia or high anxiety. They may be able to provide a mild sedative prescribed by your doctor to keep you relaxed. For more severe claustrophobia, an open CAT scan machine may be available.

Bring along a comfort item like a blanket or stuffed animal. Also having a friend or loved one present for support can help minimize anxiety.

Try to distraction yourself by going to a happy place in your mind or focus on positive thoughts. You can also visualize yourself somewhere peaceful.

Knowing when you will get results can provide reassurance the scan will be over soon. Ask your doctor beforehand so you can plan relaxing activities afterwards.

Scan Alternatives

In some cases, a CAT scan may not be the ideal imaging test. MRI and ultrasound are common alternatives to CAT scans in certain situations.

An MRI (magnetic resonance imaging) uses magnets and radio waves instead of radiation to produce detailed images of the body. MRIs provide better contrast between soft tissues compared to CAT scans. They are often preferred for imaging the brain and spinal cord. However, MRIs take longer to perform and are more expensive (Source:

Ultrasound uses high-frequency sound waves to produce images of internal organs and structures. It does not use ionizing radiation. Ultrasound is often used to image the pelvis, kidneys, liver, gallbladder, pancreas, heart, and blood vessels. It can provide real-time imaging of structures in motion, like the heart. Ultrasound is not as detailed as a CAT scan for assessing some pathologies (Source:


To recap, a CAT scan typically takes 10-30 minutes from start to finish, with the actual scan lasting only seconds. It’s important to lie still during the scan to prevent blurring and allow for clear images. Understanding your scan results properly requires reviewing them with your doctor, who can explain any areas of concern in the context of your symptoms and medical history.

A CAT scan is a diagnostic radiology procedure that uses X-rays and a computer to create cross-sectional images of your body. It provides valuable information about diseases, injuries, or other issues that may not show up well on a regular X-ray. While you are briefly exposed to radiation, the benefit of diagnosing medical problems early generally outweighs this small risk.

Being prepared for your CAT scan by following instructions for any necessary preparation helps ensure you get the most accurate results. Lying still once inside the scanner allows for the clearest images. After your scan, ask your doctor when you can expect to get the results, and make sure to follow up with any recommended next steps.

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