As we enter the final countdown to this year’s London Marathon, thousands of runners are training hard and making their last minute preparations to compete in the world’s largest single annual fundraising event.
What is it
CT (computerised tomography) uses X-rays which pass through your body to create lots of ‘thin slice’ images of the part of the body that is scanned. These images are taken by the radiographer (specialist imaging technician) who then processes and reconstructs the thin slices into meaningful, detailed images including 3-D imaging, for the radiologist (specialist doctor trained in imaging) to then review and produce a diagnostic report which is then sent back to the referring doctor to help arrange a suitable treatment plan for the patient.
What it is used for
CT scans are used to:
- Diagnose problems with bones and joints as well as internal organs
- Monitor conditions, such as tumours
- Increasingly used to plan surgery in helping to develop custom-implants e.g. in hip replacements
- CT-Guided intervention can help radiologists to diagnose and/or treat certain musculoskeletal conditions e.g. needle biopsy of a mass lesion or injection around nerve roots to alleviate pain
What to expect
You will be asked to lie on bed that passes into the CT scanner which looks like a circle (often nicknamed as the ‘donut’), which rotate around whichever section of your body is being scanned as you pass slowly through the scanner. You will need to lie very still to prevent the images from blurring.
A CT scanner does not surround your whole body like an MRI scanner so it is less claustrophobic.
The radiographer (specialist technician who takes the images) will sit in an adjacent room but will be able to hear and speak to you throughout. You may be asked to hold your breath or breathe in or out during the scan.
After positioning for the scan, it takes minutes to complete the CT scan depending on the body regions being scanned.
Before and after
There is little preparation required for CT imaging in musculoskeletal applications. You may be administered with a special dye into a joint prior to scanning to help look for any pathology inside the joint. If so, it is advisable not to drive or operate any heavy machinery to enable you to recover safely. Sometimes, an injection of dye goes into your veins, to outline certain structures better via a cannula (small plastic tube inserted into your arm or hand), dependent on the clinical history and scan requested by your referring doctor.