Shoulder MRI - Indications, Instructions, Procedures and Risks

Introduction:

The shoulder is one of the body's largest and most anatomically complex structures. It comprises several joints, tendons, ligaments, and muscles and is supplied by a rich vascular network. It serves various vital functions in the body and is an essential bone that provides the body's structural framework. The shoulder joint is a ball and socket joint where the bone of the upper arm fits into a hollow depression within the scapula (shoulder blade). Another crucial joint comprises the scapula and the collarbone (clavicle). These joints are protected by individual capsules, tendons, and muscles. The rotator cuff is a prime shoulder joint muscle that tends to keep the ball and socket joint firm and intact. Considering the wide anatomical consideration, shoulder joints are more vulnerable to injuries and degenerative changes. Shoulder injuries and disorders can affect any part of the shoulder. Hence it is necessary to understand and diagnose the condition appropriately for prompt management.

What Is an MRI of the Shoulder?

MRI (magnetic resonance imaging) of the shoulder is a noninvasive diagnostic test used to produce a detailed image of the shoulder joints and their associated structures, such as the muscles, tendons, and ligaments. It uses magnetic fields and radio waves to capture the images.

Where Is Shoulder MRI Indicated?

MRI of the shoulder is indicated primarily for trauma, injuries, or unexplained pain. In addition, it is indicated in the following conditions associated with the shoulder:

• Dislocation of the shoulder joint.

• Degenerative diseases such as arthritis.

• Fractures.

• Unexplained pain and swelling.

• Decreased or impaired mobility of the joint.

• Tear and injury of the rotator cuff.

• Infections.

• Tumors or cysts.

• Post-operative follow-up.

What Are the Instructions to Be Followed Before an MRI of the Shoulder?

• Patients are advised to wear loose, comfortable clothes.

• Patients can take their regular diet, and no fasting is required unless specified by the doctor.

• Patients who have asthma or any allergic history towards medications, contrast material, general anesthesia, or latex should inform the doctor before the procedure.

• Ladies who are pregnant or who could be should inform the doctor.

• Lactating mothers should also inform the doctor as they may be required to stop breastfeeding if a contrast MRI is performed.

• Patients on dialysis or with renal disorders should inform the doctor as the contrast material used in MRI is gadolinium-based, as it may cause nephrogenic complications.

• Claustrophobic patients (fear of closed spaces) may inform the doctor and request sedatives.

• Patients should remove all metallic jewelry or accessories, including watches, hair pins, earrings, and body piercings.

• Patients should remove their hearing aids or removable dental appliances before the procedure.

• Patients with metal implants, cardiac pacemakers, cochlear implants, aneurysmal clips, and defibrillators should first be evaluated for safety before the procedure.

• Electronic watches, mobile phones, and other electronic devices should also be removed before the procedure as they may interfere with the radio waves and magnetic field.

How Is the MRI of Shoulder Done?

• Patients are advised to change into a hospital gown.

• It is usually done on an outpatient basis and the entire procedure may take 45 minutes to an hour.

• The patient will be assisted to the diagnostic room and made to lie on an examination table.

• If a contrast MRI has to be performed, then an intravenous line (IV) is accessed on the arm.

• Claustrophobic patients may be given a sedative through the same IV line before the procedure.

• The MRI unit comprises a tunnel-like chamber into which the examination table slides to and fro.

• Certain straps and bolsters may be used to help the patient remain still.

• A small coil-like device would be placed around the shoulder to send and receive the radio waves.

• Once the table moves into the MRI unit, a computer captures and processes the images.

• Patients may be asked to remain still while the images are being captured.

• The technician and the radiologist would be present in an adjacent room; however, they may be able to communicate with the patient through an intercom.

• Patients might hear loud thumping or whirring noises, which is normal; however, they may request earplugs if they find it uncomfortable.

• An arthrography may be required in select patients before MRI, where a contrast material is injected into the joint for better and more precise images.

• Once the desired images are obtained, the IV line will be removed, and the patients will be assisted to the recovery room.

What Are the Instructions After the MRI Is Done?

MRI is a relatively simple and noninvasive procedure. Hence no special instructions are required after the procedure. Patients can resume their routine activities and regular diet after the procedure. Patients who have received a contrast MRI may be advised to drink plenty of fluids so that the dye material gets expelled through urine and stool. Lactating mothers are advised not to breastfeed for the next 24 to 48 hours till the contrast material is removed from the body. They can pump and store the breast milk before the procedure for later use. Patients who have received sedation are advised not to drive back home and seek some assistance.

What Are the Risks Associated With the Procedure?

• Mild risk of allergic reaction to contrast material.

• Patients with metal implants, pacemakers, and defibrillators may be advised of other diagnostic procedures like CT (computed tomography) scans.

• Lactating mothers should avoid breastfeeding their infants for 24 to 48 hours after the procedure if they have received a contrast material.

• A rare possibility of bruising and hemorrhaging at the site of IV.

What Are the Benefits of the Procedure?

• MRI is the gold standard diagnostic procedure for imaging soft tissues.

• Noninvasive.

• Well tolerated by the patients.

• No risk of radiation is involved.

What Are the Limitations of the Procedure?

• Contraindicated in pregnant women.

• Since Gadolinium-based contrast materials can cause nephrogenic complications, they should be rationally avoided in chronic renal disease or dialysis patients.

How Are the Results Interpreted?

Normal MRI shoulders will reveal no abnormalities in the joint size and structure or associated structures. There would be no underlying pathologies. An abnormal MRI may indicate the following:

• Traumatic injuries.

• Bone dislocation or subluxation.

• Rotator cuff tear.

• Bone infections (osteomyelitis).

• Bleeding.

• Tumor or degenerative cysts.

• Degenerative diseases such as joint arthritis.

• Tendinosis.

• Labrum tears.

Conclusion:

MRI is a common and relatively straightforward procedure. Considering its varied advantages and zero radiation protocol, it has a wide application in diagnostic and therapeutic medicine. With the increasing prevalence of shoulder pain and associated conditions, MRI is a highly sensitive and precise imaging tool to diagnose shoulder disorders.