Our neuroradiology department has Siemens Definition Edge multi-slice CT scanner.
Our CT patient information leaflet will tell you more about what to expect during your appointment.
CT Patient information leafletWhat is a CT scan
A CT scan is a diagnostic medical test that, like traditional x-rays, produces multiple images or pictures of the inside of the body.
The cross-sectional images (slices) generated during a CT scan can be reformatted in multiple planes, to provide very accurate, three dimensional information.
CT is excellent at showing most internal structures of the body and sometimes an injection of a contrast media is used to improve the information being displayed.
This injection is usually given through a vein in the arm. Once positioned on the scan couch nothing will touch you.
The procedure is painless and usually takes between 5 – 15 minutes to complete.
What does the CT scan look for?
A head or brain CT examines the various structures of the brain and is used to look for a mass, stroke, area of bleeding, or blood vessel abnormality. It can also very clearly visualise the bone structure of the skull.
CT is very useful in detecting problems with the bony structure of the spine and can indicate problems such as fractures, bony erosion, tumours, ruptured discs and spinal cord impingement.
Modern scanners allow three dimensional reconstructions which gives fantastic definition and can assist in surgical planning and assessment.
CT angiography (CTA)
In CT angiography (CTA), computed tomography is performed whilst injecting a contrast material into a peripheral vein, to produce detailed images of both blood vessels and tissues.
A CTA can show whether a vessel is blocked, where the blockage is, and how big the blockage is.
The test can also show whether there is an aneurysm (bulge) or a build-up of fatty material called plaque in a blood vessel.
How do they work?
In many ways CT scanning works very much like other x-ray examinations.
Different body parts absorb the x-rays in varying degrees. It is this difference in absorption that allows the body parts to be distinguished from one another on an x-ray or CT electronic image.
In a conventional x-ray exam, a small amount of radiation is aimed at and passes through the part of the body being examined, recording an image on a special electronic image recording plate.
Bones appear white on the x-ray; soft tissue, such as organs like the heart or liver, shows up in shades of grey, and air appears black.
With CT scanning, numerous x-ray beams and a set of electronic x-ray detectors rotate around you, measuring the amount of radiation being absorbed throughout your body.
Sometimes, the examination table will move during the scan, so that the x-ray beam follows a spiral path.
A special computer program processes this large volume of data to create two-dimensional cross-sectional images of your body, which are then displayed on a monitor.
When the image slices are reassembled by the computer software, the result is a very detailed multidimensional view of the inside of the body.
Refinements in detector technology allow nearly all CT scanners to obtain multiple slices in a single rotation. These scanners, called multi-slice CT allow thinner slices to be obtained in a shorter period of time, resulting in more detail.
How long do they take?
Modern CT scanners are so fast that they can scan through large sections of the body in just a few seconds.
Such speed is beneficial for all patients but especially children, the elderly and critically ill, all of whom may have difficulty in remaining still, even for the brief time necessary to obtain images.
What happens when I have the CT scan?
The radiographer will check your details and then go through a safety checklist with you before positioning you on the CT examination table lying on your back.
Next, the table will move quickly through the scanner to determine the correct starting position for the scans. Then, the table will move slowly through the machine as the actual images are acquired.
If contrast is required, depending on the type of exam, it will be injected through a small needle placed in your arm.
You may be asked to hold your breath during the scanning. Any motion, whether breathing or body movements, can lead to artefacts on the images.
This loss of image quality can resemble the blurring seen on a photograph taken of a moving object.
The CT examination usually takes between 10 -20 minutes.
Please contact us before your appointment:
- If you are, or may be pregnant you must tell us.
- If you are diabetic
- If you have any kidney problems
Contact us
Telephone: 0191 282 3669
