REVIEWARTICLE Reversible Cerebral Vasoconstriction Syndrome, Part 2: DiagnosticWork-Up, Imaging Evaluation, and Differential Diagnosis

SUMMARY: The diagnostic evaluation of a patient with reversible cerebral vasoconstriction syndrome integrates clinical, labora-tory, and radiologic findings. Imaging plays an important role by confirming the presence of cerebral vasoconstriction; monitoring potential complications such as ischemic stroke; and suggesting alternative diagnoses, including CNS vasculitis and aneurysmal subarachnoid hemorrhage. Noninvasive vascular imaging, including transcranial Doppler sonography andMR angiography, has played an increasingly important role in this regard, though conventional angiography remains the criterion standard for the evaluation of cerebral artery vasoconstriction. Newer imaging techniques, including high-resolution vessel wall imaging, may help in the future to better discriminate reversible cerebral vasoconstriction syndrome from primary angiitis of the CNS, an important clinical distinction. ABBREVIATIONS: PACNS primary angiitis of the CNS; RCVS reversible cerebral vasoconstriction syndrome; TCD transcranial Doppler sonography; VWI vessel wall imaging Reversible cerebral vasoconstriction syndrome (RCVS) is aclinical and radiologic syndrome characterized by the hyper-acute onset of severe headache and reversible segmental vasocon-striction of the cerebral arterial vasculature.1-5 In the first part of this review, we discussed the historical background, possibl