Regional cerebral blood flow in fibromyalgia - Single-photon-emission computed tomography evidence of reduction in the pontine tegmentum and thalami

Objective. To determine whether regional cerebral blood flow (rCBF) is abno rmal in any cerebral structure of women with fibromyalgia (FM), following a report that rCBF is reduced in the thalami and heads of caudate nuclei in FM. Methods. Seventeen women,vith FM and 22 healthy women had a resting single- photon-emission computed tomography (SPECT) brain scan to assess rCBF and a T1-weighted magnetic resonance imaging (MRI) scan to enable precise anatom ic localization. Additionally, all participants underwent 2 manual tender p oint examinations and completed a set of questionnaires evaluating clinical features. SPECT scans were analyzed for differences in rCBF between groups using statistical parametric mapping (SPM) and regions of interest (ROIs) manually drawn on coregistered MRI. Results. Compared with control subjects, the rCBF in FM patients was signif icantly reduced in the right thalamus (P = 0.006), but not in the left thal amus or head of either caudate nucleus. SPM analysis indicated a statistica lly significant reduction in rCBF in the inferior pontine tegmentum (correc ted P = 0.006 at the cluster level and corrected P = 0.023 for voxel of max imal significance), with consistent findings from ROI analysis (P = 0.003). SPM also detected a reduction in rCBF on the perimeter of the right lentif orm nucleus. No correlations were found with clinical features or indices o f pain threshold. Conclusion. Our finding of a reduction in thalamic rCBF is consistent with findings of functional brain imaging studies of other chronic clinical pain syndromes, while our finding of reduced pontine tegmental rCBF is new. The pathophysiologic significance of these changes in FM remains to be elucida ted.