What is Direct Arthrography?

Arthrography is medical imaging to evaluate conditions of joints. It can either be direct or indirect. Indirect arthrography is a medical imaging technique in which contrast material is injected into the blood stream and eventually absorbs into the joint.

With direct arthrography, however, the contrast material is injected directly into the joint by a radiologist. Direct arthrography is preferred over indirect arthrography because it distends or enlarges the joint thus allowing for enhanced imaging of small internal structures. This leads to improved evaluation of diseases or conditions within the joint. It is often performed only if a non-arthrographic exam is felt to be inadequate in assessing a joint abnormality.

There are several methods to perform direct arthrography.

Conventional direct arthrography of a joint often uses a special form of x-ray called fluoroscopy to guide and evaluate the injection of iodine contrast material directly into the joint. In some cases, ultrasound may be used to guide the procedure. Alternate methods of direct arthrography examinations may also use magnetic resonance imaging (MRI) or computed tomography (CT) following contrast material injection into the joint.

An x-ray (radiograph) is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Imaging with x-rays involves exposing a part of the body to a small dose of ionizing radiation to produce pictures of the inside of the body. X-rays are the oldest and most frequently used form of medical imaging.

Fluoroscopy makes it possible to see bones, joints and internal organs in real time. When iodine contrast is injected into the joint, it fills the entire joint which becomes clearly visible during x-ray evaluation, allowing the radiologist to assess the anatomy and function of the joint. Although the injection is typically monitored by fluoroscopy, the examination also commonly involves taking radiographs for documentation. These images are most often stored and viewed electronically.

Similarly, direct MR arthrography also involves the injection of a contrast material into the joint. The contrast material used for MR evaluation is different from that used for x-ray; it contains gadolinium, which affects the local magnetic field within the joint and appears on the MR images. As in conventional direct arthrography, the contrast material outlines the structures within the joint, such as cartilage, ligaments and bones, and allows them to be evaluated by the radiologist after the MR images are produced.

MRI uses a powerful magnetic field, radiofrequency pulses and a computer to produce detailed pictures of organs, soft tissues, bone and virtually all other internal body structures. The images can then be examined on a computer monitor connected to an image archive (PACS system) or printed or copied to CD. MRI does not use ionizing radiation (x-rays).

CT direct arthrography uses the same type of contrast material as conventional direct arthrography and may be supplemented by air to produce a double contrast CT arthrogram. CT makes cross sectional images processed by a computer using x-rays.

What are some common uses of the procedure?

Arthrographic images help physicians evaluate alterations in structure and function of a joint and help to determine the possible need for treatment, including arthroscopy, open surgery or joint replacement.

The procedure is most often used to identify abnormalities within the:

• shoulder
• elbow
• wrist
• hip
• knee
• ankle

The procedure is often used to help diagnose persistent, unexplained joint pain or discomfort. In some cases, local anesthetic medications or steroids may be injected into the joint along with the contrast material. These medications may temporarily decrease joint-related pain or inflammation and provide physicians additional information about possible sources of pain.