Radiology Services

Newspaper Column

Question: My back was hurt in an accident a few weeks ago, and my doctor said I would need some tests to decide the seriousness of the problem. What kind of tests should I expect?

Answer: As always, a specific answer to this question begins with a visit to your doctor, an examination, and review of the mechanism of injury and the symptoms that resulted from the injury. Often, simple x-rays of the back can determine that no fracture or dislocation was present, and perhaps only muscle relaxants or pain medications are enough to get you through the soreness after an accident.

If the examination and the persistent symptoms indicate the need, your doctor may recommend a Magnetic Resonance examination. This is usually the case when there is some kind of radiation of pain from the back into some other part of the body. For instance, if the pain is in the lower back, there could be pain radiating to the hip, knee, ankle or foot. This may be a clue that there has been injury to a nerve root in the spine, and the radiation suggests there could be a spur or disc in the spine pressing on the nerve root.

Magnetic Resonance (MR) scans are done with the patient lying on a couch inside a magnetic “doughnut” where there are pulses of radio waves that energize the atoms in your tissues to make them send signals to the detectors making pictures of your anatomy. These pictures show your spine, and the nerves, spinal fluid, discs and soft tissues around the area of interest. They also show whether there has been some hidden fracture that might not have shown in the regular x-rays.

If there is a specific distribution of radiating pain or numbness, we usually know where to look the closest, since there are what are called “dermatomes” that have been mapped out in the nervous system to give a good prediction of the level in the spine that may have a problem. Sometimes the problem may be in the neck, with numbness, tingling, pain or weakness in the shoulder, arm or hand. Problems from injuries in the upper back and chest may radiate to the sides of the chest or into the flank. Low back injuries or degenerative disease is more frequent than all of those in the neck or thorax. Those are the ones that cause pain, weakness, numbness, tingling or what is called “paresthesia” in the hips, thighs, knees, ankles or feet.

All of the MR scans require focusing the detectors on a certain area, since we must concentrate on the place most likely to be the problem. So, when the technologist asks you a lot of questions, it is to help make sure the right focus is going to be used on the exact part of the body likely to give the answers to the diagnostic question.

We usually have patients fill out a series of questions about their symptoms and history to help in deciding the organization of how the scan is to be performed.

In the past, anyone with a heart pacemaker could not undergo MR examination because the magnetic field would upset the pacing function to the heart. Hopefully, the new pacemakers now being tested are using fiberoptic technologies may make it possible to use MR imaging in patients who have pacemakers. Those with the old type pacemakers will be excluded from using MR unless they are changed out for the new type. The fiberoptic pacers are still experimental, and not available for general use at this time........