Spinothalamic Assessment by Magnetic Resonance Tractography. New Contributions in the Pathophysiology of Pain in Patients with Syndrome X

Abstract

Background Syndrome X is associated with signs and symptoms of ischemia without significant coronary artery obstruction. In these patients there is an increased perception of cardiac stimuli although the cause of this disorder is unknown. Objective The aim of this study was to analyze sensory nerve tracts involved in abnormal perception of pain in women with syndrome X. Methods This prospective study included 24 women: 12 with syndrome X; 6 with documented coronary heart disease, and 6 healthy controls. Lateral spinothalamic tract mapping by diffusion tractography was performed. The anatomic features (lines, voxels, and length) and physical features (fractional anisotropy, apparent diffusion coefficient, and diffusivity) of each tract were analyzed. Results The lateral spinothalamic tract was isolated in all patients. No differences were found in the physical characteristics of the tracts, but there was a significant difference in the number of voxels of the syndrome X group when compared to the other two groups (101.2 ± 46.9 vs. 83.2 ± 24 vs. ± 66 ± 16, p = 0.030), with a tendency towards a larger number of lines in each tract. Conclusions Differences in the anatomic characteristics of tracts were found in syndrome X patients with respect to healthy controls and coronary artery disease patients, with indemnity in the physical characteristics of the fibers. This is probably the first experimental study to show that it is possible to evaluate “in vivo” neurological tracts involved in pain transmission in syndrome X patients, opening a new field of research.