CT Scans and Metal Implants | Action Medical Research | Children's Charity | Children's Charity

Picture this: clear CT scans for patients with metal implants

This research was completed on 31 July 2008

Published on 7 October 2005

Pictures from CT scanners have helped bone surgeons make huge improvements in the outcome of operations. But metal implants, such as plates and screws, inserted during surgery render subsequent scans useless by obscuring the detail. Researchers hope to find a way to see both the metal and bone more clearly.

What's the problem and who does it affect?

CT scanners provide extremely useful images

CT scanners are sophisticated x-ray machines that can produce amazingly clear and detailed three-dimensional pictures of inside our bodies. They are particularly good at imaging bone. Bone surgeons use CT scans with great success when planning operations. For example, if someone has bone cancer, surgeons use CT to see the size, shape and position of tumours so they can plan how best to remove them.

Implanted metal renders CT useless

Bone surgery often involves implanting metal, such as metallic prostheses used to replace a section of bone, or metallic plates and screws used to hold broken bones in place while they heal. The problem is, once the metal is implanted, it causes streaks on CT images that are so severe they obscure the surrounding area. Surgeons can't then use CT scans to monitor, for example, how well a bone is healing, whether a tumour is recurring or what's gone wrong if their patient suffers a complication after surgery.

What is the project trying to achieve?

Finding a way to see bone and metal clearly

Helped by an earlier grant from Action Medical Research, the research team developed software that eliminates streaks from CT images of bones containing an implanted metal nail. But patients normally have implants that consist of multiple components, such as plates and screws, customised to suit their individual needs. The shape and size of each piece of metal, and their orientation with respect to each other, vary from patient to patient.

So, in this project, the researchers plan to develop software that eliminates streaks caused by multiple pieces of metal. This software must decipher how the metal disrupts the x-ray beams as they pass through the body during scanning.

What are the researchers' credentials?

Project LeaderMr S R Watt-Smith FDSRCS MD
Project team
  • Dr S J Golding, FRCR
  • Dr J J Liu, PhD
LocationNuffield Department of Surgery, Oral and Maxillofacial Surgery Department and Magnetic Resonance Imaging Department at John Radcliffe Hospital, Oxford
Duration3 years
Grant awarded7 July 2005
Start date1 August 2005
End date31 July 2008
Grant amount£145,212.00
Grant codeAP1042

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The Radiology Research Group, Nuffield Department of Surgery, Oxford, is a group of clinicians, scientists and radiographers with a special interest in scanning technology and techniques. Their interests include scanning patients with implantable metalwork, reducing the radiation dose of scans without affecting quality, special scanning techniques for oral cancers, and new scanning techniques for Magnetic Resonance Imaging. The group specifically researches areas that have the potential for significant clinical impact, so maximising their collective expertise. Because the group's members have varied clinical backgrounds and experience, they feel this gives them an edge over their competitors. They are fortunate to have access to up-to-date scanners, both CT & MRI, and scientists to advise them on the efficiency of proposed research ideas.

Who stands to benefit from this research and how?

Developing versatile software for one and all

The researchers hope their work will eventually mean all patients who have implanted metalwork can reap the benefit of CT scanning. Their ultimate aim is to produce software that works for anyone ­ no matter what type of implant the patient has or which particular brand of CT scanner the hospital uses.

Researchers believe that if successful, the software would influence millions of patients worldwide, because implantable metalwork would no longer obscure essential anatomical detail. Bone surgeons would be able to use CT to monitor their patients' progress after operations involving implanted metal. They could see how well broken bones are healing, check whether tumours are recurring, check the well-being of joint replacements and find out what's gone wrong if patients suffer complications. The pictures could also help surgeons tackle more complex surgery.

All sorts of different people could benefit

People of all ages stand to benefit from this tremendous advance. Children can need surgery for inherited disorders, to correct abnormalities in their spine or limbs, for example, arthritis causes bone damage in vast numbers of older people, with many needing hip replacements, injuries can affect anyone at any age – the list goes on and on.

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