3T MRI thalamic segmentation reveals no macrostructural changes in interictal episodic migraine without aura compared to healthy controls

Background: The thalamus plays a central role in the pathophysiology of migraine, particularly through its involvement in the thalamocortical network. Structural changes in this region may underlie the altered sensory processing observed in migraine. This study aimed to assess volumetric differences in the thalamus and its subregions between patients with episodic migraine without aura and healthy controls, using MRI acquired during the interictal phase. Methods: Thirty patients with episodic migraine without aura (MO) and 30 healthy controls (HCs) of comparable age and sex underwent high-resolution T1-weighted MRI and full ophthalmological evaluation. All patients were scanned during the interictal phase and were not receiving preventive treatment. Volumetric segmentation made using FreeSurfer’s automatic segmentation software (v7.4.1) included the entire thalamus and 25 subregions. General linear models were used to assess volumetric differences, controlling for age, sex, and total intracranial volume. Results: No statistically significant differences were found in the total thalamic volume or in any of its subregions between MO patients and HCs (puncorrected >0.05). Moreover, no correlations emerged between thalamic volumes and clinical characteristics of migraine (attack frequency, attack duration, severity of pain, HIT-6, MIDAS, ASC-12, and days since the last attack, pFDR corrected >0.05). No relevant ophthalmological abnormalities were detected. Conclusions: Our findings suggest that thalamic macroscopic volumes are not altered during the interictal phase in patients with MO and without relevant ocular abnormalities. Complementary approaches—such as functional or microstructural imaging—may be required to further elucidate thalamic involvement in migraine pathophysiology.