Brain Imaging: A Technological Breakthough in the Assessment of Pain
By Milan Stojanovic
In the early nineteenth century, physicians treating pneumonia did not recognize its cause (germs) and so did not know how to provide appropriate treatment. Two hundred years later, physicians treating chronic pain are in pretty much the same boat. Often, they are unable to identify the cause of pain and so are limited in their understanding of how to treat it. Although there are many treatments available for chronic pain, they do not always offer complete relief and, for some, relief appears to be unavailable.Until recently, a major stumbling block was the unavailability of a “test” for pain. There is, however, a new research tool that seems to be shedding some light on the origins of pain. It is called functional brain imaging.Functional brain imaging makes use of two recently-discovered technologies: positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). Both methods work by measuring blood flow through the brain. The fMRI resembles the regular magnetic resonance imaging picture of the brain’s anatomy, except that areas of the brain that are active during the experience of pain are seen as small red islands on an otherwise gray, detailed picture of the brain. While the fMRI looks at brain anatomy, PET looks at metabolic activity within the brain. Using these technologies in combination, researchers are now able to identify the exact parts of the brain involved in the experience of pain.Through functional brain imaging, researchers have discovered that the brain reacts differently in people with chronic pain, when compared with “pain-free” individuals. Moreover, in different kinds of chronic pain, the fMRI and PET brain pictures can vary. This is particularly important, since different kinds of pain tend to respond to different medical treatments. These findings can help medical researchers to use functional brain imaging to tailor drug treatments to specific kinds of chronic pain.Although still in its infancy, in the near future brain imaging may become the “test for pain.” Its use can greatly benefit the many people who suffer from chronic pain and, by providing hope for treatment, the depression that often accompanies it.