Q: Why did my doctor order an mri?

Whenever your doctor requires top-quality anatomic portrayal, especially soft tissue, chances are that an MRI will be the modality of choice. Unfortunately, the decision to prescribe or not to prescribe an MRI will not always be made on the basis of diagnostic quality.

Sometimes, in a well-meaning attempt to save money for the patient or the insurance company, a physician will choose a less-expensive procedure, hoping that he or she will receive sufficient information to make a correct diagnosis. If the less-expensive test proves inadequate, however, and an MRI is prescribed later, the attempt to save money will have been futile. Even worse, the condition may be inaccurately diagnosed using a less definitive, non-MRI procedure.

A recent court case helps illustrate the point. A Minnesota jury recently awarded a couple $1.25 million because two physicians treating their son, Philip, at Park Nicollet Medical Center failed to prescribe an MRI to assist them in making their diagnosis. Over a period of 18 months beginning in the fall of 1989, they treated the boy for attention deficit hyperactivity (ADH). Finally, when no progress was noted, the parents took it upon themselves to consult a neurologist at the University of Minnesota. The specialist promptly prescribed an MRI and soon afterward properly diagnosed the boy's condition as metachromatic leukodystrophy, a degenerative brain disease which can often be reversed with a bone marrow transplant. For young Philip, however, it was too late. He had surgery for MLD in December 1991 and died in the summer of 1992. Had an MRI been prescribed without undue delay, chances are the boy would still be living.

Neurologists are just one medical specialty that depend a great deal upon MRI for accurate diagnostic information. Other medical specialties and healthcare providers that rely in great numbers upon MRI include neurosurgeons, orthopedic surgeons and chiropractors. Because MRI portrays soft tissue with such diagnostically-useful clarity, it is relied upon frequently for revealing abdominal abnormalities-mid-field scanners are clearly superior to high-field scanners in this regard-and a wide variety of other ills as diverse as malfunctioning temporomandibular joints (TMJs) in the jaw, pinched nerves in the spinal column, heart disease and multiple sclerosis. (Nothing is superior to MRI for revealing MS.) From the beginning, of course, one of the great strengths of MRI has been its ability to reveal tumors.

Incidentally, don't let the fact that MRIs provide great soft-tissue imaging mislead you into thinking that they aren't great for many types of musculoskeletal imaging. In fact, the second largest application for MRI at present is musculoskeletal disease. Orthopedic physicians regularly refer patients for MRIs for a wide variety of conditions. That's why you hear so much, for example, about professional athletes getting MRI scans. FONAR has been a pioneer in the development of a number of specialized MRI diagnostic methods used in sports medicine. It has led the way, for example, in providing anatomical motion studies. These studies enable technologists to electronically sequence a series of MRI images to create an accurate portrayal of how a malfunctioning joint in a patient is working dynamically. Individual MRI images reveal static conditions, just as a photo snapshot reveals a person's likeness just for an instant of time, but misses the facial expression that occurred a second or two earlier and the one that followed immediately after. A dynamic portrayal of a joint helps a physician understand how a particular joint-a shoulder, a knee, a neck or a TMJ-functions in "real life." Incidentally, open-environment MRI scanners such as FONAR manufactures are clearly superior for these motion studies as they provide the space required for a patient to move their arm, leg or neck through a wide range of positions. Magnetic resonance angiography (MRA) is a well-utilized procedure that will only increase in use by cardiologists in the future. Although CAT scans are better able to show calcified plaque that has built up in an artery, physicians will increasingly turn to MRA in the future to reveal the presence and severity of soft atherosclerotic plaque. In other words, it will reveal newer, more recent plaque which has formed, enabling physicians to view the extent of artery disease more accurately and to treat that disease more appropriately. Incidentally, patients who require life-support systems-heart patients, for example-can be imaged in a FONAR MRI scanner. Although more and more non-magnetic devices are being developed for use around "supercon" scanners with large fringe fields, normal life-support systems with ferromagnetic components have been used around FONAR scanners for years because of their vertical magnetic fields. Nothing is superior to an MRI for imaging breast implants. It shows the implants much more clearly than other modalities and it has the added advantage of not using X-rays, a particular concern when imaging the breast. MRI is also superior to ultrasound, X-ray mammograms or CAT scans when it comes to revealing malignancies in very dense breasts. This is still a developing area for MRI, one which will become much more dominant in the future. The MRI applications mentioned above are just a small portion of the applications for which MRI is the modality of choice. If you have further questions, discuss them with your physician or speak with a radiologist who specializes in MRI. MRI is still a developing modality whose diagnostic power is becoming more and more appreciated with time. Already, it has replaced a great number of X-ray-based procedures and it is certain to replace even more in the future.

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