Diagnostic Procedures

Computed Tomography, abbreviated as CT, is a procedure that uses a computerised, narrow beam of X-rays that are aimed at the body of a patient in a rotating circle. The procedure is generally quite quick but can range in length depending on the type of scan being performed. The rotating X-rays produce cross-sectional image slices (processed by the computer of the scanner), which provide a greater detail than traditional X-ray.

MRI stands for Magnetic Resonance Imaging. It is a type of scan that uses a strong magnetic field and radiowaves to create images of the body based on the hydrogen content of tissues. It can provide excellent information about the soft tissues in the whole body as well as the bones, joints and spine and is very useful for diagnosis. It does not use ionising radiation unlike radiographs and CT but is one of the longest imaging tests and can take around 15-30 minutes to complete.

Ultrasound is an imaging technique using high frequency sound (high enough that it is not audible and is able to pass through the body) to produce anatomical images of the body. First gel is applied to the region of the body being scanned – this facilitates the transmission of sound waves into the body. Sound waves then enter the body via a probe placed on the skin in a completely painless way. The sound is reflected or absorbed by tissues in the body differently (similar to sonar in a submarine) and its frequency changes as a result. The altered frequency of the reflected sound is recorded by the probe as an echo and an image is then generated which reflects the different parts of the anatomy.

A radiograph is an imaging test used to produce images of the body, particularly the bones and joints, chest, abdomen and pelvis. It is generated by passing x-rays from an x-ray source machine, through the part of the patient that needs imaging and onto a digital x-ray detector on the other side. The different tissues in the body absorb the x-rays by differing amounts according to their density and change the energy of the x-ray photons, altering how they expose the x-ray detector (similar to light affecting photographic film). X-rays are a part of the electromagnetic spectrum (which includes visible light) and are a form of ionising radiation.