CT Scan – Wrist

About a CT scan of the wrist

The wrist is made up of eight small carpal bones, including the scaphoid, which sit between the ends of the two forearm bones (the radius and ulna) and the bones of the hand. A CT (computed tomography) scan uses X-rays and a computer to make detailed cross-section pictures of these bones, which can be turned into 3D images.

A wrist CT may be used to look at:

• scaphoid fractures – to confirm a break that did not show on X-ray, and to see whether the bone has moved out of place (displacement), which affects whether surgery is needed
• scaphoid fractures that have not healed (non-union), or to check whether a fracture has healed before you return to normal activities
• broken wrist (distal radius) fractures that extend into the joint, to help surgeons plan an operation
• fractures of the other small wrist bones, and the joint between the radius and ulna (the distal radioulnar joint)
• arthritis, bone cysts and lumps, and healing around plates and screws

For a suspected scaphoid fracture when X-rays are normal, NICE recommends MRI as the first scan, with CT used if MRI is not suitable. For ligament and cartilage injuries, such as scapholunate ligament or TFCC tears, a wrist MRI or wrist MRI arthrogram is usually better. For problems further along the arm or hand, see forearm CT, hand CT or thumb CT. When you book, choose the left or right side.

What happens during the scan

You usually lie on your front with your arm stretched above your head (sometimes called the “superman” position), or sit beside the scanner with your hand resting on the bed. Pads help keep your wrist still. If you have a cast or splint, it can usually stay on. The radiographer controls the scanner from the next room, but can see, hear and talk to you throughout. The scan itself takes only a few minutes. Contrast dye is not usually needed; where it is needed, it is charged separately.

Is CT safe?

CT uses X-rays, which are a type of ionising radiation. A wrist CT gives a very low dose, because the wrist is far from the organs that are most sensitive to radiation – usually less than the natural background radiation you receive in a few days. The risk from a single scan is very small, and every CT scan is checked by a radiologist or radiographer to make sure the benefit of the scan outweighs the risk, as required by the Ionising Radiation (Medical Exposure) Regulations. If you have had other CT scans recently, tell us when you book.