Post-infectious central nervous system vasculitides in adults: an underdiagnosed and treatable disease part II. Neuroimaging of selected etiologies : Part II. Neuroimaging of selected etiologies.

Introduction: As detailed in the first part of this review, post-infectious vasculitides are a wide and complex category, including several clinical, microbiological and neuroradiological patterns. In order to raise the suspicion for diagnosis, the knowledge of two different neuroradiological issues is needed, i.e. the knowledge of neuroimaging pattern of infections and the one of neuroimaging pattern of vasculitis.

Aims: The main aim of this second part is to summarize the neuroradiological features of post-infectious vasculitides focusing on imaging of vessels and consequences of vessel involvement, continuing the discussion proposed in the first part about neuroimaging of infections. In some cases, the two neuroradiological issues are both simultaneously present in the same patient, but in other cases only the second one can be depicted due to the latency between infection and vasculitis.

Findings: Beyond general features of cerebral vascular involvement in post-infectious vasculitides, some well-studied and homogenous diseases, as treponemal vasculitis, Varicella Zoster Virus (VZV) arteriopathy, neuroborreliosis, SARS-CoV2-related endotheliopathy are described in detail, being not rare and sometimes underdiagnosed. The main clinical and neuroradiological features of these conditions are deeply addressed, providing diagnostic clues and pictorial examples.

Conclusions: Although some general features are common in clinical presentation and neuroimaging of post-infectious vasculitides, there are few neuroimaging clues pointing out a specific microbial agent as causative. The main step is to raise the diagnostic suspicion in order to start the dedicated investigation pathway and treatment.