Brain perfusion abnormality in patients with chronic pain.

We performed single photon emission computed tomography (SPECT) of the brain in 15 patients with chronic pain (males, 7; females, 8; average age 49.1 +/- 17.9 years) and identified the locus of cerebral blood flow reduction by a new analytical method (easy Z-score Imaging System: eZIS) to clarify the functional neuroanatomical basis of chronic pain. Of the 15 patients, 6 had backache, 2 neck pain, 2 gonalgia, and 5 pain at other sites, with an average Visual analog scale of pain (VAS) value of 6.1 +/- 1.9. In comparison with a information on a data base on physically unimpaired persons, the dorsolateral prefrontal area (both sides, right dominant), medial prefrontal area (both sides), dorsal aspect of the anterior cingulate gyrus nociceptive cortex (both sides) and the lateral part of the orbitofrontal cortex (right side) were found to have blood flow reduction in the group of patients with chronic pain. As for chronic pain and its correlation with clinical features such as a depressive state, anticipation anxiety, PTSD, and conversion hysteria, the mechanism in the brain that was suggested by this study should be followed-up by functional neuroimaging studies.