Magnetic Resonance Imaging (MRI)

An MRI allows us to produce extremely detailed pictures of body tissues and organs without the need for x-rays. During an MRI, electromagnetic energy is measured and analyzed to produce both two- and three-dimensional images that can be viewed on a computer monitor. This advanced imaging technology allows for the evaluation of some body structures that may not be as visible with other imaging methods.

Areas of Application

MR Angiography

MR angiography (MRA) is an MRI study of the blood vessels. It utilizes MRI technology to detect, diagnose and aid in the treatment of heart disorders, stroke, and blood vessel diseases. MRA provides detailed images of blood vessels without using any contrast material, although a special form of contrast material is often given to make the MRI images even clearer. The procedure is painless, and the magnetic field is not known to cause tissue damage of any kind.


  • Many patients with arterial diseases are now being treated in the radiology department rather than undergoing surgery in an operating room. MRA is a very useful way of finding problems with blood vessels and determining how to best to treat those problems.
  • The carotid arteries in the neck that conduct blood to the brain are a common site of atherosclerosis (hardening of the arteries), which may severely narrow or block off an artery, reducing blood flow to the brain and even causing a stroke. If an ultrasound study shows that such disease is present, many surgeons will perform the necessary operation after confirmation with MRA, dispensing with the need for conventional, invasive vascular techniques.
  • MRA has found wide use in checking patients for diseased intracranial (in the head) arteries.
  • MRA is also used to detect disease in any of the vessels in the chest, abdomen, pelvis, and extremities.
  • Patients with a family history of arterial aneurysms, a ballooning out of a segment of the vessel wall, can be screened with MRA to see if they have a similar disorder that has not produced symptoms.
  • If an aneurysm is found, it may be treated, possibly avoiding serious or fatal bleeding.

MRI of the Body (Abdomen and Pelvis)

MRI of the body provides clear and detailed pictures of internal organs and tissues. It has proven to be extremely valuable for the diagnosis of a broad range of pathologic conditions in all parts of the body. It allows physicians to evaluate certain body structures that may not be as visible with other imaging methods.


  • Organs of the chest, abdomen, and pelvis are examined in high detail with MRI, enabling the diagnosis and evaluation of tumors and functional disorders.
  • Because no radiation exposure is involved, MRI is often the preferred diagnostic tool for examination of the male and female reproductive system and urinary tract.

Body MRI Mink Radiologic Imaging

MRI of the Head

MRI of the head has proven to be very helpful to radiologists in diagnosing tumors of the brain as well as disorders of the eyes, sinuses, and the inner ear. An MRI of the head is the most sensitive exam for brain tumors, strokes and certain chronic disorders of the nervous system such as multiple sclerosis.


  • Detection of tumors, strokes, and numerous disorders within the nervous system.
  • Can depict brain function.
  • Detection of areas with tissue abnormality in patients with disease of the eyes, sinuses, or the inner ear.
  • Images of the brain, spine, joints and soft tissue structures are clearer and more detailed than with other imaging methods.
  • Can detect strokes at a very early stage.
  • There is no exposure to x-rays during an MRI study.

MRI of the Head Los Angeles Radiology

Musculoskeletal MRI

The parts of the musculoskeletal system that are most frequently imaged with MRI are the spine, knee, and shoulder. However, MRI has also been used to study almost every joint in the body including the hips, wrists, and feet. Because MRI can give such clear pictures of soft tissue structures near and around bones, it is usually the best choice for examination of the body’s major joints, the spine for disk disease, and soft tissues of the extremities.


  • Widely used to diagnose sports-related injuries, as well as work-related disorders caused by repeated strain, vibration or forceful impact.
  • Locate and identify the cause of pain, swelling or bleeding in the tissues in and around the joints and bones.
  • Detection of even very small tears and injuries to tendons, ligaments, and muscles and some fractures that cannot be seen on x-rays.
  • Diagnosis of degenerative disorders such as arthritis, deterioration of joint surfaces, or a herniated disk.
  • MR images of the soft tissue structures of the body such as the muscles, tendons, joints, and blood vessels, are clearer and more detailed than with other imaging methods.
  • MRI enables the detection of abnormalities, injuries, and diseases that might be obscured by bone tissue with other imaging methods.
  • MRI provides a fast, noninvasive way to assess a variety of muscle and joint injuries and disorders.
  • The detail of MR images makes them an invaluable tool in early diagnosis and evaluation of tumors and infection.

MRI of the Spine

MRI is most frequently used to determine the etiology of neck pain, lower back pain, and radiating extremity pain. MRI of the spine is also used to evaluate tumors and neurologic conditions. The examination shows the anatomy of the vertebrae and discs that make up the spine, as well as the spinal cord and the neural foramen (the spaces between the vertebrae through which nerves pass).

MRI is frequently done to help plan surgeries on the spine such as the decompression of a pinched nerve or spinal fusion. MRI is performed after spinal surgery to re-evaluate diseased discs and less frequently to look for post-operative scarring, bleeding or infection.


  • Detection of bulging, degenerated or extruded intervertebral disc, a frequent cause of neck, lower back pain, and radiculopathy/sciatica.
  • Diagnosis of compressed (or pinched) and inflamed nerves.
  • MRI is an excellent method of obtaining clear, detailed images of the bony structures and soft tissues of the spine, including the spinal cord. It demonstrates abnormalities, injuries and diseases in the spinal region that may not be visualized with other imaging methods.
  • It is especially helpful for diagnosing or ruling out acute compression of the spinal cord when clinical examination shows muscle weakness or paralysis.
  • MRI is able to detect subtle changes in the vertebral column that may be an early stage of infection or tumor. The procedure may be better than CT or bone scans for evaluating tumors, abscesses and other masses near the spinal cord.

MRI Benefits Vs. Risks


  • Images of the brain, spine, joints and soft tissue structures are clearer and more detailed than with other imaging methods.
  • On the occasion that IV contrast is needed, an MRI is less likely to produce an allergic reaction than the iodine-based materials used for conventional x-rays and CT scans.
  • There is no exposure to radiation.
  • Has the ability to detect abnormalities that might be obscured by bone tissue.
  • New MRI systems can depict brain function, and in this way detect a stroke at a very early stage.


  • The examination poses virtually no risk when appropriate guidelines are followed.
  • Metal implants may be affected by the magnetic field. The procedure should be avoided in any patient with a pacemaker, implanted neurostimulator, certain types of metallic ear implants (cochlear implants) or metallic object within the eye socket. An MRI should also be avoided if the patient has a port for delivering insulin or chemotherapy (however, many ports are detachable so patients can safely undergo MRI examinations). If you have an implant, please bring the implant identification card or letter from the physician who placed the implant. Please note: most orthopedic appliances such as artificial hips, knees, hearts stents, and valves are all imaged safely.
  • Pregnant patients should be informed that, to date, there has been no evidence that the use of clinical MR imaging during pregnancy produces any harmful effects. For more information, please see our Patient Safety Guidelines section and click the link to Pregnancy and MRI.
  • Women who are breastfeeding should inform their radiologist and ask how to proceed. MRI poses no risk to milk or breast tissue.
Learn More About Mri Examinations

How Do MRIs Work?

MRI is a unique imaging method because, unlike the usual radiographs (x-rays), radioisotope studies and even CT scanning, it does not rely on ionizing radiation. Instead, radio waves are directed at protons, the nuclei of hydrogen atoms, in a strong magnetic field.

The protons are first “excited” and then “relaxed,” emitting radio signals, which can be computer-processed to form an image. In the body, protons are most abundant in the hydrogen atoms of water – the “H” of H2O – so that an MRI image depicts differences in the content and distribution of water in various tissues.

With MRI, different types of tissue within the same body structure are clearly displayed in fine anatomic detail. In the spine, for instance, fatty tissue, cerebrospinal fluid, and the intervertebral discs contain considerable water, more than is found in bone, cartilage, and nerve tissue. MRI is well-suited to detecting conditions that increase the amount of fluid, such as tumors, inflammation, and infections. Even different types of tissue within the same organ, such as the gray and white matter of the brain, can easily be distinguished. Special imaging techniques are used to image various structures, such as arteries in the case of MR Angiography, or MRA.

How is an MRI Performed?

During an MRI, you will be placed on a special table and positioned inside the opening of the MRI unit. A typical exam consists of two to six imaging sequences, each taking two to 15 minutes. Each sequence provides a specific image orientation and a specified degree of image clarity or contrast. Depending on the type of exam being done, the total time needed can range from 20 to 60 minutes, not counting the time needed to change clothing and answer questions.

When the contrast material is needed, a substance called gadolinium is given by IV injection during one of the imaging sequences. This material highlights blood vessels and pathology, making them stand out from surrounding tissues.

If you are having your shoulder, knee, or other specific joint imaged, direct injection of contrast into the joint may be required. The injection is performed either prior to, or about half-way through, the exam. The technologist leaves the room during the actual imaging process, but the patient can communicate with them at any time using an intercom. A friend/relative may stay in the room.

When the exam is completed, you may be asked to wait to make sure that more images are not needed.

Next, learn about an open MRI.