An arthrogram is a series of images of a joint after injection of a contrast medium, usually done by fluoroscopy or MRI. The injection is normally done under a local anesthetic. The radiologist or radiographer performs the study using fluoroscopy or ultrasound to guide the placement of the needle into the joint and then injects an appropriate amount of contrast.
When you arrive for an arthrogram, you will be screened for internal metals to confirm that you are a candidate for the MRI to follow.
You will be taken into the room where the part to be scanned will be isolated using a sterile drape. It is important that you do not touch the top of the drape, cough over it, or move it. The radiologist will clean the area with an antiseptic solution. A local anesthetic will be injected into skin surface, then when numb, the needle will be advanced deeper where additional numbing medicine will be injected.
The procedure will be performed under fluoroscopic guidance. Fluoroscopy is performed with the c-arm, a piece of equipment that allows real-time visualization to allow the radiologist to view the tip of the needle and know when it is in the proper place in the joint. X-ray contrast will be injected to confirm the needle placement, then an MRI contrast mixed with saline will be injected for visualization in the MRI scan. The injection will cause the joint to feel heavy and full. Your usual pain medication will alleviate that discomfort if it continues after your exam is completed.
Once the needle placement is confirmed and the contrast is injected, the needle will be removed, and you will be taken to the MRI suite where detailed images of the joint will be obtained.
In some cases, a CT scan will be ordered rather than an MRI, but most of the process is identical. If you are scheduled for a CT scan rather than MRI, the MRI contrast/saline mix will not be injected, as the x-ray contrast is visualized better on CT scans.
You may be asked to change clothes or remove your electronics and other objects from your pockets, depending on the body part to be examined. Zippers, snaps, cell phones, coins, etc., will “over-shadow” the area of interest if they are present, so removing those items is in your best interest for an accurate exam.