What is the difference between a regular hip MRI and an arthrogram of the hip?

March 5, 2010

MRI or magnetic resonance imaging of the hip makes use of magnetic waves to stimulate the hip tissues into producing signals. These signals are recorded by a scanner and then analyzed to produce cross-sectional images of the hip. A hip MRI helps to check for disease, damage and inflammation of the muscles, ligaments and tissues of the hip. An MRI machine is shaped like a hollow tube with a table in the centre. There is usually a separate room for a MRI scan with the machine located in the centre. The controls are located at the side behind a window. This is a painless and safe procedure, but requires the individual to remain still and motionless for a period of time that can range from 10 to 45 minutes. Some individuals may experience discomfort from remaining still within a confined space for a prolonged period of time. Newer models of the MRI machine have been introduced recently wherein the scanner is located overhead, but the walls on the sides of the table are removed. All magnetic substances must be removed from the body such as metal clips or pins. An MRI also cannot be conducted on individuals with pacemakers.

An arthrogram is used to radiologically examine the tissues of the joints by injecting a contrast dye into the area. Arthrography is commonly done on the joints of the shoulder and knee. This procedure may also be performed on the wrist, elbow, ankle and hip. A hip arthrogram is used to examine congenital abnormalities in the area. Detection of a loose hip prosthesis may also be done through this procedure.

In an arthrogram procedure, the area of the affected joint is first cleaned and then a sterile drape is applied. The area is numbed with a local anesthetic and the radiologist inserts a needle into the joint. The placement of the needle is guided with the help of x-ray images. If infection of the joint is suspected, fluid may be extracted and sent to the laboratory for analysis. A test injection of the contrast dye is done to check for correct placement. The dye is then injected into the area and the needle is removed. A dressing is applied to the area of injection. The joint may be manipulated so that the contrast dye is properly distributed over the entire joint area. X-rays of the joint are taken before the contrast dye spreads to the surrounding tissue or gets absorbed into the joint. The entire procedure takes about 30 to 60 minutes.

Submitted by M T on March 5, 2010 at 01:58

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