[Altered Brainstem Volume in Medication-overuse Headache: A Pilot Magnetic Resonance Imaging Evaluation]

Objective To investigate the altered brainstem volume in patients with medication-overuse headache(MOH). Methods The high-resolution structural images were obtained from 36 MOH patients and 32 normal controls(NC).The brainstem was segmented into midbrain,pons,and medulla,whose volume were measured respectively.Results There was a significantly smaller midbrain volume in MOH patients [(5.80±0.53) ml] than that in NC [(6.14±0.67)ml](t=2.36,P=0.02).The volumes of pons,medulla,and whole brainstem showed no significant difference in MOH patients [(13.13±1.42)ml,(4.55±0.51)ml,and(23.48±2.23)ml,respectively] compared with those in NC [(13.67±1.61) ml,(4.66±0.44) ml,and(24.47±2.56) ml,respectively](t_pons=1.47,P_pons=0.15;t_medulla=0.93,P_medulla=0.35;and t_brainstem=1.71,P_brainstem=0.09,respectively).Conclusion A smaller midbrain volume may be one of the specific features of pain pathway in MOH,and the automated brainstem subfield segmentation and volumetry may be useful tools for evaluating brainstem alternation in MOH patients.