White blood cell SPECT during active period of cluster headache and in remission

Background and purpose:  Cluster headache (CH) is an episodic headache disorder characterized by recurrent, unilateral attacks of excruciating pain in the temporal/orbital region. The pathophysiology of CH is largely unknown although involvement of immunological mechanisms has been suggested. The aim of our study was to investigate whether patients with CH show signs of intracranial inflammation, when using white blood cell single‐photon emission computer tomography (WBC‐SPECT). Methods:  We have examined 14 patients with CH, both in active period and in remission, and five control subjects at one occasion, with WBC‐SPECT. To be able to precisely define regions of interest (ROI:s) in the brain, all patients with CH and control subjects underwent magnetic resonance imaging (MRI) of the brain. Results:  We found no significant difference in 99m Tc‐labeled WBC uptake between patients with CH in active period and controls. Furthermore, patients with CH in active period were not significantly different in uptake compared with patients with CH in remission. Conclusions:  These results did not provide conclusive support for a hypothesis of a pathophysiological role of inflammation intracranially. Our conclusions are restricted to the advantages and limitations of the chosen method.