SURGICAL APPROACHES TO EPILEPSY: SURGERY FOR PARTIAL (FOCAL) SEIZURES – MAGNETIC RESONANCE SPECTROSCOPY AND MAGNETO-ENCEPHALOGRAPHY
Magnetic resonance spectroscopy. Magnetic resonance imaging, which we have previously discussed as a technique for visualizing brain structures, can also be used in a somewhat different form to study brain metabolism. Used in this fashion it is called magnetic resonance spectroscopy. By using far more powerful magnets and different receivers, this technique can “tune in” to the energy changes that occur as one chemical compound is converted to another within the living cells. Thus, as energy is utilized to fire cells during seizures, this energy can be detected and analyzed. As cell membranes change with this firing, or with recovery after their electrical discharge, these changes can be studied. As this new technology continues to develop, it should be possible to understand better the chemistry and spread of human seizures and to develop and visualize the effects of new drugs to block the development and spread of seizures.
Magneto-encephalography. If the U.S. Navy can use changes in magnetic fields to detect a submarine 1,000 feet under the sea from a satellite many thousands of feet in the air, then we should be able to detect the changes in magnetic fields generated by a seizure focus two inches under the scalp. And we are beginning to do so.
Submarines, being made of metal, create a minute disturbance of the earth’s magnetic field, a disturbance that can be accurately localized by the proper instrumentation in the satellite. Using similar technology, laboratory investigators are beginning to be able to localize the tiny changes in magnetic fields of the surrounding brain, created by the firing of cells. In not too many years it should be possible to localize accurately epileptic foci deep within the brain.
Progress in these areas is mind-boggling.