CT Scan – Foot

About a foot CT scan

The foot contains 26 bones and more than 30 joints, which work together to support your weight and absorb the impact of walking and running. 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. CT shows bone and joint surfaces in more detail than any other scan.

A common reason for a foot CT is a fracture that is complex or hard to see on X-ray, for example:

• heel bone (calcaneus) fractures, often after a fall from a height, where CT shows how the joint surface has broken and helps plan treatment
• Lisfranc injuries, damage to the bones and ligaments in the middle of the foot, which can be subtle on X-ray but important to treat correctly
• fractures of the talus and other small bones of the foot

A CT may also be used to look at arthritis, including before joint fusion surgery; tarsal coalition, a bony or fibrous bridge between two foot bones that can cause stiffness, pain and flat feet, often first noticed in teenagers; bunions and other deformities before surgery; fracture healing; and bone lumps.

For stress fractures, tendon and ligament problems, Morton’s neuroma and infection, a foot MRI or ultrasound is usually better. For the ankle joint, see ankle CT. When you book, choose the left or right side.

What happens during the scan

You lie on the scanner bed, usually feet first, with your foot supported by pads so it stays still. Only your lower leg and foot go through the scanner, which is a short, open ring. Some centres can scan the foot while you stand, to show how the bones line up under your weight. If you have a cast or boot, 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 contrast is needed, it is charged separately.

Is CT safe?

CT uses X-rays, which are a type of ionising radiation. A foot CT gives a very low dose, because the area scanned is small and far from the organs most sensitive to radiation. 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.