An arthrogram is an x-ray fluoroscopy of a joint performed with a sequential digital subtracted spot films after injection of a contrast agent.

See Arthrography.

An arthrography is a radiographic examination of a joint (such as the knee, shoulder, hip, elbow or wrist) that requires an injection of a contrast medium into the joint space.
For an opaque x-ray arthrography a water-soluble iodinated contrast agent is injected and a series of fluoroscopic controlled images is produced. Magnetic resonance arthrography combines the arthrogram with MRI. A small quantity of gadolinium contrast agent is added to the injection into the joint space. The traditional radiographic images are followed by an MRI of the extremities. A non-invasive possibility is an indirect MR arthrography, which doesn't require the injection into the joint. The dye is given prior to the imaging procedure.
The contrast fluid produces a bright signal and allows evaluation of small defects of the joint capsule, assessment of articular surface and labral cartilage, and in case of an indirect arthrogram also of the surrounding soft tissue. If a gaseous medium is used, this exam is called pneumoarthrography and a combination with liquid contrast is used in double-contrast arthrography.
MR arthrography is often used to evaluate hip and acetabular labrum, shoulder rotator cuff and glenoid labrum (see Shoulder MRI), and less often in wrist and knee MRI studies. Also combinations of CT and nuclear medical techniques with arthrography are available.