Methods for imaging human brain pathophysiology of chronic pain

Magnetic resonance (MR) imaging techniques are rapidly expanding to provide anatomical, physiological, and biochemical information that can be used to noninvasively study the human brain across these dimensions. In this chapter we concentrate on the application of functional MR imaging and MR spectroscopy to understand the brain pathophysiology of chronic pain states. We demonstrate the novel hypotheses that can be tested by these methods in specific patient populations, and argue that the approaches developed are generic enough to be applicable to a large list of clinical pain conditions. We emphasize functional magnetic resonance imaging (fMRI) adapted specifically to understand the neuronal activity of the brain that underlies clinical pain states, and studies of brain biochemistry of chronic pain patients in comparison to normal subjects using in vivo hydrogen magnetic resonance spectroscopy (H-MRS). The results we have obtained by both approaches indicate that the brain pathophysiology of chronic pain is different from normal subjects, and both methods show abnormalities in the same brain regions: patients with chronic sympathetically mediated pain and patients with chronic back pain show that the prefrontal cortex is critically involved in such conditions.