Functional magnetic resonance imaging for the assessment of autonomic dysfunction in patients with antineutrophil cytoplasmic antibody-associated vasculitides

Introduction Nervous system involvement is common in antineutrophil cytoplasmic antibody-associated vasculitides (AAV). While the involvement of the peripheral and central nervous system is well described, it is still unclear how and to what extent the autonomic nervous system ( ANS) is affected. Functional magnetic resonance imaging (fMRI) can provide information on both structure and potential damage of the brain, as well as on the function of selected brain centers. Objectives The aim of this study was to investigate the ANS dysfunction in AAV patients and its correlation with the results of fMRI performed during the Valsalva maneuver. Patients and methods A total of 31 patients with AAV and 30 healthy controls were enrolled in the study. Each participant completed the Composite Autonomic Symptom Score (COMPASS)-31 questionnaire. MRI was performed using a 3T scanner. The participants were asked to perform the Valsalva maneuver according to the fixed protocol, and their airway pressure was monitored. During the maneuver, fMRI data were collected. The generalized least-squares time series analysis and the region-of-interest (ROI) analysis were subsequently performed. Results The patients with AAV had a higher median COMPASS-31 score than the controls ( 12.86 vs 2.99, respectively; P < 0.01). Structural MRI investigation did not reveal any significant differences between the groups. The brain centers involved in ANS function were detected during fMRI; however, the ROI analysis showed no differences between the study patients and controls. Conclusions The patients with AAV reported symptoms related to the ANS dysfunction; however, no differences with respect to the functioning of the ANS brain centers were demonstrated between these patients and healthy controls in the fMRI study during the Valsalva maneuver.