Intra-arterial application of nimodipine in reversible cerebral vasoconstriction syndrome: a neuroradiological method to help differentiate from primary central nervous system vasculitis

BACKGROUND: Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by a prolonged, but self-limiting segmental cerebral vasoconstriction. Neurological outcomes vary, but can be severe. The clinical hallmark of RCVS is thunderclap headache, which might come along with further neurological symptoms. Distinguishing RCVS from other entities, such as primary angiitis of the central nervous system (PACNS), is of utmost importance for appropriate therapy. The angiographic response to intra-arterial nimodipine application has been suggested as an additional diagnostic criterion for RCVS but confirmatory studies are limited. We aimed to evaluate the angiographic nimodipine test. METHODS: We reviewed retrospectively the clinical and imaging data of 13 RCVS patients, who were admitted to a single German neurological department between January 2013 and December 2020. RESULTS: Out of 13 patients diagnosed with RCVS, 4 patients underwent an angiographic nimodipine test. In all 4 patients cerebral vasoconstriction completely resolved during nimodipine application. Among the four patients with a positive test, there was one individual, in whom a response was detected after a delay of 60 min. In all patients, we found a complete resolution of cerebral vasoconstriction within 12 weeks. CONCLUSION: Our findings support the usefulness of the application of nimodipine in diagnosing RCVS. Prolonged angiographic observation of the vascular response after nimodipine injection is important.