Evaluation of the Pons, Midbrain, Thalamus, Hippocampus, and Trigeminal Nerve with MRI in Patients with Cluster Headache

Objective: We investigated the volumetric changes of the brain structures and trigeminal nerve diameters in cluster headache (CH) by cranial MRI. Methods: The cranial MRI images of 30 adult patients with CH and 30 adult subjects with normal cranial MRI results were included. In both groups, pons, midbrain, thalamus, and hippocampus volumes; and trigeminal nerve diameters were measured. Results: There were no significant differences between pons (p=0.849), midbrain (p=0.855), bithalamic (p=0.553Right, p=0.523Left), and hippocampus volumes (p=0.930Right, p=0.698Left). In CH group, trigeminal nerve diameter (2.38±0.47 mm) was non-significantly higher than the control group (2.29±0.44 mm) (p=0.131). In the CH group, left thalamus and right hippocampus volumes were significantly higher than the contralateral side (p<0.05). In CH group, there were positive correlations between the pons and thalamus (p=0.037Right and p=0.037Left) and hippocampus volumes (p=0.002Right, p=0.005Left); midbrain and bithalamic volumes (p=0.001Right, p=0.001Left); and right trigeminal nerve diameter (p=0.029); thalamus and pons(p=0.037Right, p=0.037Left); and midbrain volumes (p=0.001Right, p=0.001Left); right and left hippocampus volumes (p=0.000); right and left trigeminal nerve diameters (p=0.000). In females, right hippocampus volumes were smaller than those in males (r= ˗0.374, p=0.042). Conclusion: In CH patients, left thalamus volume was higher; and left hippocampus volume was lower. In CH patients, the limbic system and especially left hippocampus may be affected and get lower in volumetric analysis. Additionally, the right thalamus is affected showing lower volume in CH patients.