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.
A Standing CT is different to a normal CT Scan in that the patient remains standing while the scan is taking place. Rather than passing radiation through your whole body, in a Standing CT just your feet and ankles are scanned. This allows images to be taken while your weight is applied to the foot and ankle as opposed to when the weight is off during a normal, lying down CT.
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.
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 the 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.