Abstract
Dear Sir We appreciate the response of Dr Schoenen to our HSA-SPECT study on cluster headache patients and regret not to have mentioned his Gallium-SPECT study on cluster headache (CH) patients and migraineurs. Sianard-Gainko and co-workers had studied 30 CH patients (eight chronic CH patients, and 22 episodic CH patients in either active period or remission) and seven migraineurs without aura to test the inflammatory hypothesis in CH. In contrast to our study, SPECT scans were not acquired during an acute attack, and furthermore they were not co-registered with MRI and were solely analysed on a visual basis. No significant differences between the active period and the remission phase were found.
Similar to the study by Sianard-Gainko and co-workers, which was prompted by a preliminary report by Gawel et al., our study was prompted by a previous oral report by Goebel. In his abstract, Goebel had mentioned a significant accumulation of human serum albumin in the ipsilateral cavernous sinus of CH patients (1). One important focus of our study was therefore to re-evaluate whether human serum albumin is a suitable method to detect intracranial inflammation in the context of CH attacks. Altogether, the cavernous sinus hypothesis was neither confirmed using Gallium nor human serum albumin and SPECT, neither in the pain-free phase nor in the attack. These negative findings might be resolved in the future with advances in neuroimaging techniques.