RESUMO
OBJECTIVE: To assess the frequency of symptomatic structural lesions and the diagnostic yield of conventional brain MRI in cluster headache (CH). BACKGROUND: In contrast to migraine, brain MRI is recommended in patients with CH to exclude potential mimics. The prevalence of symptomatic CH is not known. METHODS: We retrospectively analysed in detail the brain MRIs of patients diagnosed as CH in 3 Neurology Services in Spain and reviewed their clinical history. Clinical diagnoses were reassessed based on the ICHD-3 criteria. RESULTS: We included 130 patients: 113 (86.9%) were male; mean age at diagnosis being 41.4 years (range 7-82). Forty-nine (37.7%) showed some abnormal MRI finding. Only in two cases potential symptomatic lesions were found: one trigeminal schwannoma and one craneopharyngioma, but both presented atypical features (facial hypoesthesia on examination and episodes of prolonged duration that had progressed to continuous refractory pain without specific pattern, respectively) and therefore did not fulfil the ICHD-3 CH criteria. The remaining abnormal MRI findings were: white matter lesions (24 patients; 18.4%), sinus inflammatory changes (13; 10.0%), small arachnoid cysts (5; 3.8%), empty sella turca (3; 2.3%), and other unspecific findings (8; 6.2%). All of them were not symptomatic based on neuroimaging characteristics, clinical course and response to treatment. CONCLUSIONS: Brain MRI in patients who meet ICHD-3 CH criteria, with no atypical clinical features, does not show any clinically-relevant findings, suggesting that these criteria are highly predictive of its primary origin and that systematic MRI is not useful for the diagnosis of typical CH.