About a hand CT scan
The hand and wrist contain 27 bones: eight small carpal bones in the wrist, five metacarpals in the palm, and 14 phalanges in the fingers and thumb. A CT (computed tomography) scan uses X-rays and a computer to make thin, detailed cross-section pictures of these bones, which can be turned into 3D images. CT shows small bones and joint surfaces in more detail than any other scan.
The most common reason for a hand CT is a fracture that is complex or hard to see on X-ray, for example:
- scaphoid fractures – the scaphoid is a small wrist bone at the base of the thumb that often breaks in a fall onto an outstretched hand. NICE recommends considering MRI as the first scan for a suspected scaphoid fracture, but CT is used to show how far a fracture has moved, to check healing, and to look for a non-union (a fracture that has not joined)
- hook of hamate fractures, often in golfers and racquet sports players, which are very hard to see on X-ray
- fractures that enter the finger and knuckle joints, and fractures with several pieces, to help plan surgery
A CT may also be used to look at arthritis, bone lumps and cysts, and the position of screws and wires after surgery.
For ligaments, tendons, soft tissue lumps and bone bruising, a hand MRI or ultrasound is usually better. For the thumb, see thumb MRI or thumb CT, and for the wrist bones, see wrist CT. You can read more in our article on hand imaging. When you book, choose the left or right side.
What happens during the scan
Depending on your comfort and the scanner, you either lie on your front with your arm stretched above your head, or on your back with your hand by your side. Your hand rests on a pad and is held still with supports. 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 contrast is needed, it is charged separately.
Is CT safe?
CT uses X-rays, which are a type of ionising radiation. A hand 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.
What the scan can show
A hand CT can help to look at:
- scaphoid fractures, healing and non-union
- hook of hamate and other carpal bone fractures
- complex fractures of the fingers and palm
- fractures entering the joints
- arthritis and bone spurs
- bone lumps and cysts
- screws and wires after surgery
When to get urgent help: go to A&E or an urgent treatment centre if your hand or finger looks misshapen after an injury, you cannot move your fingers, or your fingers feel numb, cold or look pale. Get help the same day for pain at the base of the thumb after a fall onto your hand, even if your X-ray was normal.
Preparing for your scan
No special preparation is needed, and you can eat and drink normally. Remove rings, watches and bracelets before your appointment. Upload any previous X-ray or scan reports and letters from your surgeon when you book, and remember to choose the correct side.
Wear loose, comfortable clothing without metal zips, poppers or buttons, and leave jewellery at home, as metal in the scan area can affect the pictures. You may be asked to change into a gown. Unlike MRI, CT is not affected by pacemakers or most metal implants, and the scanner is a short open ring rather than a tunnel, so it is usually easier for people who feel anxious in enclosed spaces.
Tell the team before your scan if you are, or might be, pregnant or breastfeeding, if you have kidney problems, diabetes (especially if you take metformin), asthma, thyroid problems or allergies, or if you have had a reaction to contrast dye before. If you need contrast, you may be asked for a recent kidney blood test result.
Frequently asked questions
Should I have a CT or MRI for a suspected scaphoid fracture?
NICE recommends considering MRI as the first scan, as it can show a fracture straight away even when X-rays are normal. CT is useful for showing how much a fracture has moved and checking whether it has healed. Your referrer will say which is needed.
Is CT or MRI better for my hand?
CT is best for the small bones, such as complex fractures and planning surgery. MRI is better for ligaments, tendons, soft tissue lumps and bone bruising. If you are unsure, contact us before booking.
Do I need to choose a side?
Yes. Choose the left or right hand when you book. If both hands need scanning, contact us so the centre can plan the appointment.
Do I need a referral?
Because CT uses radiation, each scan has to be justified by a qualified professional before it can go ahead. Upload a referral from your GP or consultant when you book if you have one. If you do not, select “no referral” and the scanning centre will review your request and confirm the next steps with you, which may include arranging a referral.
Sources
- NICE NG38 – Fractures (non-complex): assessment and management
- Concomitant hook of hamate fractures in patients with scaphoid fracture: more common than you might think (PMC)
- NHS – Broken finger or thumb
- NHS – Hand pain
- NHS – CT scan
- UKHSA – Patient dose information: guidance
The information on this page has been gathered from various sources and is provided for general information only. It is not medical advice. TOP MRI is not liable for the accuracy or completeness of this information. Please speak to your doctor or the scanning centre about your own situation.