WHAT IS ARTHROGRAPHY?
Conventional arthrography is the x-ray examination of a joint that uses a special form of x-ray called fluoroscopy and a contrast material containing iodine. Some arthrography examinations also use magnetic resonance imaging (MRI).
An x-ray (radiograph) is a noninvasive medical test that helps physicians diagnose and treat medical conditions. X-rays are the oldest and most frequently used form of medical imaging.
Fluoroscopy makes it possible to see internal organs in motion. When iodine is injected into the joint space, it coats the inner lining of the joint structures and appears bright white on an arthrogram, allowing the radiologist to assess the anatomy and function of the joint.
MR arthrography involves the injection of a contrast material into the joint, just like in conventional arthrography, except that the contrast material is different. As in conventional arthrography, the contrast material outlines the structures within the joint. This allows them to be evaluated by the radiologist to determine the anatomy of the joint.
MR imaging uses a powerful magnetic field, radio frequency 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, printed or copied to CD. MRI does not use ionizing radiation (x-rays).
PREPARING FOR YOUR ARTHROGRAM
No special preparation is necessary before arthrography. Food and fluid intake do not need to be restricted.
You should inform your physician of any medications you are taking and if you have any allergies, especially to iodinated contrast materials. Also inform your doctor about recent illnesses or other medical conditions.
Some MRI examinations may require the patient to receive an injection of contrast into the bloodstream. The radiologist or technologist may ask if you have allergies of any kind, such as allergy to iodine or x-ray contrast material, drugs, food, the environment, or asthma. However, the contrast material used for an MRI exam, called gadolinium, does not contain iodine and is less likely to cause side effects or an allergic reaction.
The radiologist should also know if you have any serious health problems or if you have recently had surgery. Some conditions, such as severe kidney disease, may prevent you from being given contrast material for having an MRI.
If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want to ask your physician for a prescription for a mild sedative prior to the scheduled examination.
Jewelry and other accessories should be left at home if possible, or removed prior to the MRI scan. Because they can interfere with the magnetic field of the MRI unit, metal and electronic objects are not allowed in the exam room. These items include:
- jewelry, watches, credit cards and hearing aids, all of which can be damaged.
- pins, hairpins, metal zippers and similar metallic items, which can distort MRI images.
- removable dental work
- pens, pocketknives and eyeglasses
- body piercings
In most cases, an MRI exam is safe for patients with metal implants, except for a few types. People with the following implants cannot be scanned and should not enter the MRI scanning area unless explicitly instructed to do so by a radiologist or technologist who is aware of the presence of any of the following:
- internal (implanted) defibrillator or pacemaker
- cochlear (ear) implant
- some types of clips used on brain aneurysms
You should tell the technologist if you have medical or electronic devices in your body, because they may interfere with the exam or potentially pose a risk, depending on their nature and the strength of the MRI magnet. Examples include but are not limited to:
- artificial heart valves
- implanted drug infusion ports
- implanted electronic device, including a cardiac pacemaker
- artificial limbs or metallic joint prostheses
- implanted nerve stimulators
- metal pins, screws, plates, stents or surgical staples
In general, metal objects used in orthopedic surgery pose no risk during MRI. However, a recently placed artificial joint may require the use of another imaging procedure. If there is any question of their presence, an x-ray may be taken to detect the presence of and identify any metal objects.
Patients who might have metal objects in certain parts of their bodies may also require an x-ray prior to an MRI. You should notify the technologist or radiologist of any shrapnel, bullets, or other pieces of metal which may be present in your body due to accidents. Dyes used in tattoos may contain iron and could heat up during MRI, but this is rarely a problem. Tooth fillings and braces usually are not affected by the magnetic field but they may distort images of the facial area or brain, so the radiologist should be aware of them.
You may be asked to remove some or all of your clothes and to wear a gown during the exam. You may also be asked to remove jewelry, dentures, eye glasses and any metal objects or clothing that might interfere with the x-ray images.
Women should always inform their physician and x-ray technologist if there is any possibility that they are pregnant. Many imaging tests are not performed during pregnancy so as not to expose the fetus to radiation. If an x-ray is necessary, precautions will be taken to minimize radiation exposure to the baby. See the Safety page (www.RadiologyInfo.org/en/safety/) for more information about pregnancy and x-rays.
Children younger than teenagers may need to be sedated in order to hold still for the procedure. Parents should ask about this beforehand and be made aware of food and drink restrictions that may be needed prior to sedation.
You should plan to have a relative or friend drive you home after your procedure.
DURING YOUR ARTHROGRAM
This examination is usually done on an outpatient basis.
You will be positioned on the examination table and x-rays are taken of the joint to be compared later with the arthrogram.
Next, the skin around your joint is cleansed with antiseptic and a local anesthetic is injected into the area.
Your physician will numb the area with a local anesthetic.
The area where the needle is to be inserted will be sterilized and covered with a surgical drape.
A needle is then inserted into the joint space. The radiologist, a physician specifically trained to supervise and interpret radiology examinations, will use a syringe to drain the joint fluid, which may be sent to a laboratory for analysis.
The contrast material and sometimes air are injected into the joint space and the needle is removed. You will be asked to move the affected joint to distribute the contrast material throughout the space.
The conventional arthrography exam is usually completed within 30 minutes. Exams involving MRI may take more than one hour.
AFTER YOUR ARTHROGRAM
When your procedure is finished, you should feel no side effects and can resume your normal activities. You may be advised to drink plenty of fluids for a few hours after the exam. Here’s what happens next:
Our technologist prepares your images for the radiologist to evaluate.
The radiologist interprets your results and writes a report.
The report is then sent to your doctor. Your doctor will talk with you about your arthrography results and next steps