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An arthrogram is a medical procedure in which images of a joint are produced after it is injected with a contrast medium, a substance that improves visibility of the structures to be examined. The images in an arthrogram can be produced through x-rays, computerized tomography (CT) scans or magnetic resonance imaging (MRI) scans. An arthrogram is either diagnostic, with the purpose of determining the source of any illness or defects in the joint, or therapeutic, as a form of treatment for a known condition.
Either ultrasound or fluoroscopy, an x-ray procedure, is used to inspect the joint before the arthrogram is performed. The technician uses these methods to correctly place the needle within the joint to inject the contrast medium, which may be gaseous, water-soluble, or both, depending on the type of images desired. The injection is usually performed under local anaesthetic.
Next, images are collected using either fluoroscopy or CT or MRI scans. Fluoroscopy can produce images from a number of different angles, while CT and MRI imaging allows a series of cross section images to be collected. An arthrogram allows for inspection of the soft tissues of the joint, including muscles, ligaments, cartilage, tendons, and the joint capsule, none of which would be visible through a regular x-ray. A therapeutic arthrogram is typically used for joint distension or cortisone injections for a damaged joint.
In general, an arthrogram carries the same risk as any x-ray or MRI procedure. In addition, patients with an allergy or sensitivity to the local anaesthetic or contrast medium to be used should not undergo the procedure due to a risk of infection at the injection site. Other conditions that may make an arthrogram risky include pregnancy, any history of allergic reaction, asthma, arthritic pain at the time of the procedure, diabetes, or known infection in the joint to be imaged. Inform your doctor if you have any of these conditions before an arthrogram is performed.
Patients with advanced kidney disease are also subject to the risk of a potentially fatal condition known as nephrogenic systemic fibrosis (NSF) when gadolinium is used as the contrast medium in an arthrogram. NSF causes large, hardened areas of the skin to develop and reduces mobility. It can also affect the internal organs.