Imaging description

Reversible cerebral vasoconstriction syndromes (RCVS) represent a heterogeneous group of cerebrovascular disorders that share similar clinical and imaging features. These disorders are associated with thunderclap headache, with or without neurologic symptoms and transient segmental narrowing of the distal intracranial arteries [1,2]. The neuroimaging features are variable, but the presence of unilateral or bilateral cortical subarachnoid hemorrhage (SAH) is very suggestive, in the appropriate clinical scenario. The amount of blood is generally small and may manifest as hyperdensity of cortical sulci on CT (Fig. 12.1) or hyperintense signal in sulci on FLAIR sequence. Areas of infarction may be identified as areas of restricted diffusion and can be seen in as many as 7–54% of patients. The least common finding is parenchymal hematomas (Fig. 12.2).

An imaging hallmark of this disease is the presence of multifocal areas of segmental vascular narrowing (Figs. 12.1, 12.2, 12.3). Typically, more than one vascular distribution is involved and the vessels demonstrate a beaded appearance. These changes may be seen on CTA, MRA, or digital subtraction angiography (DSA). In some instances only second- and third-order vessels are involved, and therefore CTA and MRA may be false negative and DSA is required to establish the diagnosis. Of note, vascular imaging studies generally demonstrate an absence of ruptured aneurysm or a vascular malformation. The vascular changes of RCVS resolve on follow-up studies, within a period of 3 months (Fig. 12.3).