The magnetic resonance imaging (MRI) test uses a powerful magnetic field to create images of structures and organs within the body. It is a safe and noninvasive test that can help physicians diagnose a wide range of diseases and conditions without subjecting the patient to needles, radiation or radioactive isotopes. MRI can reveal tumors and functional disorders that affect digestive system organs, such as the liver and pancreas. In some cases, an MRI is performed to gain additional information after another imaging test, such as an ultrasound or computed axial tomography (CAT) scan, reveals a problem.

An MRI works by placing the patient in a chamber surrounded by a magnetic field. The center (nucleus) of atoms in the patient’s body responds to the magnetic force in characteristic ways, allowing a computer to produce clear, cross-sectional or three-dimensional images of the patient’s internal structures and organs.

MRI produces clear images that can allow physicians to locate and identify the cause of pain, inflammation or bleeding in tissues, organs and glands of the abdomen. The images are so detailed that they allow physicians to detect problems in organ function and even the smallest tears and injuries to ligaments and muscles that cannot be seen with x-rays.

Other conditions revealed by MRI examination include:

• Eye or inner-ear tissue abnormalities
• Damage caused by heart attack or heart disease
• Blood vessel plaques and blockages
• Functional disorders of organs, such as the lungs, liver, pancreas, kidney and spleen
• Strokes and chronic disorders of the nervous system
• Brain abnormalities in patients with dementia
• Diseases of the pituitary gland
• Reproductive system and bladder problems
• Various forms of cancer

Sometimes MRI involves injection of a contrast medium (dye) into a vein that increases the clarity of the images by making the body’s tissues more responsive to the machine’s magnetic and radio waves.