Abdominal MRI - Indications, Procedure, Benefits and Risks, and Limitations

Introduction

Magnetic resonance imaging (MRI) is a non-invasive test that uses magnetic fields and radio waves to capture images of internal body organs. Considering its radiation safety protocol, it has been widely used in diagnostic radiology. It also has the advantage of visualizing soft tissue without being obscured by bone or other hard tissue. Hence MRI is a significantly superior imaging tool for diagnosing unexplained conditions or abnormalities.

The abdomen, most commonly known as the belly, contains various vital organs such as the stomach, liver, kidney, pancreas, spleen, and small and large intestines. Abdominal disorders have a wide range of causes and symptoms though most frequently presented by abdominal pain. Unexplained pain or any other symptom requires thorough evaluation for diagnosis and treatment. An imaging system like MRI helps assess and evaluate the entire abdominal cavity concomitantly, concluding the diagnosis precisely and promptly without any dilemma.

What Are the Indications for an Abdominal MRI?

An abdominal MRI may be indicated in the following conditions:

• Unexplained abdominal pain or swelling.

• To evaluate abdominal and pelvic organs (liver, pancreas, kidney, bowel, stomach, spleen, uterus, ovaries, prostate, urethra, and urinary bladder).

• Tumors and cysts of the abdomen.

• Pregnancy.

• Inflammatory or infectious conditions.

• To evaluate the blood flow through the abdominal blood vessels.

• To assess the lymph nodes.

• Pelvic pain in females.

• Inconclusive physical examination.

• A previous imaging study with abnormal results.

What Is the Working Principle of MRI?

The MRI unit appears like a large cylindrical tunnel. It uses magnetic fields and radio waves to visualize the body's internal structures. The body fluids consist of hydrogen atoms which are realigned on being subjected to the radio waves. These radio waves are sent and received through certain magnetic coils that generate the magnetic field. These hydrogen atoms then realign to their original position. While doing so, they emit a considerable amount of energy which is detected by the scanner and processed by a computer into images. MRI can process a series of images, thus representing the structure precisely as thin slices.

What Are the Instructions to Be Followed Before the Procedure?

• Patients are advised to fast for four to six hours. This is done to ensure there are reduced bowel and stomach secretions and they don’t interfere with imaging. Also, the gastrointestinal movements will be minimal, thus reducing motion artifacts.

• Patients should wear loose, comfortable clothes.

• They are advised to remove any jewelry or metallic accessories before the procedure. Belts, buckles, clips, wallets, watches, eyeglasses, credit cards, mobile phones, and other metallic or electronic devices should be removed at home.

• Removable dental appliances, body piercings, and hearing aids should also be removed before the procedure.

• Patients with dental implants, cochlear implants, pacemakers, aneurysm clips, and cardiac defibrillators should be evaluated for safety before being subjected to an MRI examination.

• Patients with a history of allergy or asthma should inform the doctor before the procedure.

• Patients with chronic renal disease or on dialysis should also inform the doctor. The gadolinium-based contrast materials frequently used in MRI are potentially nephrotoxic and may result in renal failure.

• Ladies who are pregnant or think they might be should inform the doctor, as MRI is not indicated during the first trimester of pregnancy.

• Patients must carry their recent medical test reports and prescription medicines to the diagnostic center.

How Is Abdominal MRI Done?

• MRI tests are usually conducted on an outpatient basis.

• The patient will be asked to change into a hospital gown.

• They would be assisted to the scanning room and asked to lie on the examination table, which slides into the MRI scanning unit. Straps may be used to help the patient remain still during the procedure.

• Claustrophobic patients may be given sedatives to help them relax and remain calm.

• An intravenous (IV) line may be accessed for contrast MRI to inject the contrast material through the vein. Oral contrast may also be required depending on the condition being assessed.

• The magnetic coil in the form of a blanket or small devices would be placed adjacent to the area to be imaged.

• The table then slides into the MRI unit.

• Thumping and whirring noises may be heard during the procedure, which is normal. Patients may request an earplug if uncomfortable.

• Patients could communicate with the doctor and the technician through the intercom as they would be in an adjacent enclosed room throughout the procedure.

• While capturing the images, the patient might be asked to hold their breath to limit motion-related artifacts.

• The entire procedure may take roughly one hour.

What Are the Instructions After the Procedure?

• MRI is a non-invasive procedure, and 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 sedative are requested to take some assistance for driving back home.

• Patients with a contrast MRI examination are advised to drink plenty of fluids. It will help to expel the dye material from the body through urine or stool.

What Are the Benefits and Risks Associated With the Procedure?

Benefits:

• No risk of radiation.

• It is a non-invasive technique hence painless and negligible recovery time.

• Preferred diagnostic tool for soft tissue imaging.

Risks:

• Allergic reactions to the contrast material.

• Gadolinium-based contrast material may worsen renal disease resulting in renal failure.

What Are the Limitations of the Procedure?

• Though MRI is not contraindicated in implant patients, its usage has to be assessed and monitored in these patients, as strong magnetic fields may disrupt implant functioning.

• Pregnant ladies, particularly in their first trimester, are advised to avoid MRIs as the fetus would be in a strong magnetic field. Though there are no proven adverse effects on the unborn baby, postponing is advisable unless deemed medically necessary.

• Patients with neurological disorders may struggle to remain still throughout the procedure.

• Obese patients may not fit into the narrow unit though presently, many diagnostic centers prefer using larger diameter or open MRI units as they even tend to reduce claustrophobia in patients.

• Breathing and bowel movements could result in artifacts.

• It is costlier than other standard imaging tests.

Conclusion

MRI is superior and the most preferred diagnostic tool considering its non-invasive and radiation-safe protocol. It is highly beneficial to view organs and soft tissues that hard or bony structures may obscure. MRI has proved to be an invaluable tool for assessing organs' functioning and their structural phenotypes. However, considering the high cost, the possibility of motion artifacts, and the longer imaging duration, it is not the first diagnostics choice.