Imaging of the neurovasculitides

Abstract

Neurovasculitis is a term used to describe a diverse spectrum of diseases characterized by inflammation of the blood vessels that may progress to ischemic injury of the central or peripheral nervous system. The overlapping clinical and radiographic features and the complex pathophysiology make it difficult to quickly or clearly identify neurovasculitis as the etiology of a patient’s symptoms. Nonetheless, simple yet comprehensive categorization schemes established by consensus meetings and based upon the anatomy, pathophysiology, and imaging findings help to clarify the situation. For both the radiologist and the treating clinician, a systemic approach considering the triad of organ systems involved, laboratory results, and vessel size and type affected simplifies the situation. Vessel size is particularly important for the radiologist to consider as it broadly categorizes the neurovasculitides within the differential diagnosis. Imaging plays an essential role in the diagnosis of these diseases and may be divided into those studies that investigate the vessel lumen, the vessel wall, and the parenchyma. Demonstration of the vessel wall or perivascular inflammatory change is a specific and compelling finding, which should be specifically pursued by the radiologist. All imaging modalities contribute to the analysis; conventional catheter angiography is no longer the preeminent diagnostic standard. Despite the uncommon occurrence of neurovasculitis, it is important to be familiar with these diseases. They play a particularly important role in the differential diagnosis of stroke in young and middle-aged adults and typically have devastating clinical consequences. If diagnosed early, they may be effectively treated, relieving symptoms and avoiding permanent central and peripheral neurologic damage.