Assessment of hypothalamic macrostructure in episodic cluster headache: a volumetric segmentation MRI study

Purpose: The functional involvement of the hypothalamus in the pathophysiology of episodic cluster headache (eCH) is well known, but its macrostructural involvement remains unclear. In this study, we investigated differences in the volumetry of the entire hypothalamus and its subunits in patients with in-bout eCH during headache-free periods. Material and Methods: We examined hypothalamic volumes in 26 eCH patients (scanned during bout periods but outside of active attacks and off prophylactic medications) and 20 age- and sex-matched healthy controls (HCs). Magnetic resonance imaging (MRI) with T1-weighted sequences was used to perform volumetric segmentation of hypothalamic subunits (anterior–inferior, anterior–superior, posterior, tubular inferior, and tubular superior) and total hypothalamic volume. General linear models were used to assess volumetric differences, adjusting for age, sex, and total intracranial volume. Results: No statistically significant differences were found in either hypothalamic subunit volumes or total hypothalamic volumes between eCH patients and HCs (p > 0.05). Additionally, no correlations emerged between the hypothalamic volumes and CH clinical features. Conclusion: These findings align with previous studies, suggesting that CH pathophysiology may involve network-level functional alterations rather than macrostructural hypothalamic changes.