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Musculoskeletal (MSK) CT Scan
What is an MSK CT?
An MSK CT scan (computed tomography, or CAT scan) uses a special X-ray machine to take detailed pictures of the bones and joints. CT pictures are far more detailed than a standard X-ray.
How does the CT scan work?
Unlike standard X-rays, which produce pictures of the shadows cast by body structures of varying thickness, CT scanning uses X-rays in a much different way. Many X-ray beams are passed through the bone and joints at many angles, and special detectors measure the amount of radiation absorbed by different tissues. The X-ray tube revolves around you, and sends and records data from many angles, forming cross-sectional pictures (slices) of the area. The pictures are then reviewed on a computer screen.
Modern CT units, called spiral CT, produce higher-quality pictures in a shorter time. This is an important feature for children and patients who are elderly or critically ill, as well as for those who cannot hold their breath for a long time. Today’s scanners can image large regions of the body, during a single 20-second breath-hold.
How should I prepare for the CT scan?
- Wear comfortable, loose-fitting clothing for your CT exam.
- Metal objects can affect the image, so avoid clothing with zippers and snaps.
- You may be asked to remove hairpins, jewelry, eyeglasses, hearing aids and any removable dental work that could obscure the images.
- For women – inform your doctor or CT technologist if there is any possibility that you are pregnant.
How is the CT scan performed?
- The CT technologist will place you on the CT table, using pillows to help you maintain the correct position during the scan.
- For the first few scans, the table will move quickly through the scanner to check the correct starting position. The rest of the scans are made as the table moves more slowly through the hole in the scanner.
- A CT exam usually takes 5 minutes to half an hour. When the exam is over, you may be asked to wait until the images are checked to find out if more images are needed.
What will I feel during the procedure?
- CT scanning causes no pain, and with spiral CT, the need to lie still for any length of time is reduced.
- You will be alone in the room during the scan; however, the technologist can see, hear and speak with you at all times. For pediatric patients, a parent may be allowed in the room with their child to help reduce fear and provide comfort. The parent will be required to wear a lead apron to prevent radiation exposure.