What is an MRI?

First used on humans in 1971 Magnetic Resonance Imaging (MRI) is an imaging technique used primarily in medical settings to produce high quality images of the inside of the human body. MRI provides an unparalleled view inside the human body. The level of detail we can see is extraordinary compared with any other imaging modality. MRI is the method of choice for the diagnosis of many types of injuries and conditions

MRIs differ from CT Scans in that there is no exposure to radiation. The MRI equipment is basically two powerful magnets; one external and one internal. Within the human body there are millions of negative and positive charged atoms. In conjunction with radio wave pulses of energy, the MRI scanner can pick out a very small point inside the patient's body and ask it, essentially, "What type of tissue are you?" By means of a computer, the data is collected, combined, and manipulated using complex mathematical equations. The final product reveals detailed anatomical images transferred onto film. The MRI system goes through the patient's body point by point, building up a 2-D or 3-D map of tissue types. It then integrates all of this information together to create 2-D images or 3-D models.

Because of the MRI system's incredible ability to tailor the exam to the particular medical question being asked, the MRI system can cause tissues in the body to take on different appearances. This is very helpful to the radiologist (who reads the MRI) in determining if something seen is normal or not. MRI systems can also image flowing blood in virtually any part of the body. This allows us to perform studies that show the arterial system in the body, but not the tissue around it. In many cases, the MRI system can do this without a contrast injection, which is required in vascular radiology.

What is a CT/CAT scan?

CT Scan (Computerized Axial Tomography) or CAT Scan was developed in 1970. The CT Scan evolved from Tomograms; multiple x-rays taken at different levels to check the depth of an abnormality. The advent of computers in medicine has meant less radiation exposure and shorter study times. The CT Scan has become an important adjunct to x-rays. The CT Scan uses multiple x-ray beams projected at many angles in conjunction with computer resources to create three-dimensional cross-sectional images. Each image or picture reveals a different level of tissue that resembles slices.

What are EMGs and Nerve Conduction Studies?

Electromyography and Nerve Conduction Tests are ordered to learn more about the health of peripheral nerves. These tests can establish if a nerve is pinched, and give a numeric value to how severely it is pinched and often where it is pinched. The test can last anywhere from a half an hour to an hour. The quality of the results is quite dependent on the skill of the person administering the test.

During the Nerve Conduction portion of the test, electrodes much like EKG patches are placed along the known course of the nerve. The nerve is stimulated with a tiny electrical current at one point. The nerve must then transmit the signal along its course, and an electrode placed further down the arm or leg captures the signal as it passes it. A healthy nerve will transmit the signal faster and stronger than a sick nerve.

The EMG portion of the test measures the electrical activity in muscles. Muscles normally receive constant electrical signals from healthy nerves, and in return "broadcast" their own healthy electrical signals. During the EMG portion of the test, the doctor places acupuncture like needles into the muscles to record the electrical signal from the various muscles in the arm or leg. If a muscle doesn't receive adequate signals from a sick nerve, it broadcasts signals, which show the muscle is confused.

From the Nerve Conduction Test and the EMGs, the doctor can correlate which nerves are pinched and the seriousness of the condition. This information can then be used to help formulate further treatment plans.

Are X-Rays bad for you?