An arthrogram, also known as arthrography, is a specialized medical imaging test designed to provide a highly detailed look inside a joint. This procedure is employed when standard imaging, such as an X-ray or Magnetic Resonance Imaging (MRI) scan, does not provide enough clarity to diagnose joint issues. By using a contrast agent within the joint space, an arthrogram allows physicians to visualize soft tissues that are often the source of pain or dysfunction. It provides a precise picture of structures like cartilage, ligaments, and tendons that support joint function.
Defining the Arthrogram
The arthrogram is a two-part procedure that enhances existing imaging technology. The core component involves injecting a contrast medium, or dye, directly into the joint capsule. This contrast material coats the internal surfaces of the joint structures, making them visible on subsequent imaging such as X-ray, Computed Tomography (CT), or MRI scans. The contrast agent is typically a solution containing diluted gadolinium for an MRI arthrogram or an iodine-based compound for a CT arthrogram. This direct method ensures the contrast is concentrated exactly where it is needed, outlining soft tissue contours and allowing radiologists to spot minute tears or defects.
Diagnostic Applications
Doctors often recommend an arthrogram for patients with persistent joint pain, unexplained mechanical symptoms, or a limited range of motion. The procedure is uniquely suited to diagnose subtle injuries to the non-bony structures within a joint. It provides the detail necessary for surgical planning or determining the cause of continued discomfort after other tests have been inconclusive.
Common Diagnostic Uses
- Identifying tears in fibrocartilaginous rings, such as a labral tear in the shoulder or hip, or a meniscal tear in the knee.
- Assessing the integrity of tendons, including evaluating for a partial or full-thickness rotator cuff tear.
- Detecting the presence of loose bodies—small fragments of cartilage or bone floating within the joint space—that may cause locking or catching sensations.
- Evaluating surrounding soft tissues and checking for complications, such as infection or loosening of prosthetic components, in patients who have had joint replacement surgery.
Patient Experience: Preparation and Steps
Preparation
Preparing for an arthrogram involves reviewing the patient’s medication list, especially blood thinners, which may need to be temporarily stopped. Patients are often asked to arrange for transportation home, though this depends on the joint injected and facility protocol. In the imaging suite, the skin around the joint is thoroughly cleaned with an antiseptic solution. A local anesthetic, such as lidocaine, is then injected to numb the skin and deeper tissues before the main procedure begins.
The Procedure
The radiologist uses a live imaging technique, such as fluoroscopy or ultrasound, to precisely guide a thin needle into the joint capsule. This image guidance ensures the contrast is delivered accurately into the intended space. Once the needle is confirmed to be in the right location, the contrast agent is injected, which may cause a momentary sensation of fullness or pressure. After the contrast is successfully injected, the needle is removed. The patient is immediately moved to the CT or MRI scanner to capture the detailed images before the contrast is absorbed by the body.
Recovery and Safety Concerns
Following the procedure, patients are advised to rest the joint for the remainder of the day and avoid strenuous activity for 24 to 48 hours. Temporary swelling or a feeling of fullness is common due to the injected fluid, which may cause a mild, temporary increase in pain at the injection site. Some patients report a clicking or popping sensation as the contrast material is absorbed by the body. The most serious risk is infection within the joint, but this is minimized through meticulous sterile techniques during the injection. There is also a small risk of an allergic reaction to the contrast agent, so patients are monitored closely after the injection.