Delirium due to brain microembolism: diagnostic value of diffusion-weighted MRI.

Delirum is a common complication in hospitalized patients and it is characterized by acute disturbances of consciousness, attention, cognition, and perception. Despite the frequency with which it is observed, ischemic stroke is generally considered as an unusual cause of delirium. A subtype of brain embolism is characterized by multiple small emboli in different vascular territories, a condition known as "brain microembolism." Given the high contrast of acute ischemic lesions in diffusion weighted imaging (DWI) this technique is particularly helpful to detect these small infarctions. We present here a patient with pulmonary metastases who was treated with bronchial artery embolization and who subsequently developed delirium due to brain microembolism. The embolic material crossed through pulmonary arteriovenous fistulas, producing multiple areas of cerebral ischemia. The ischemic lesions could be visualized only on DWI, and they affected the periventricular region, caudate nucleus, thalamus, and cerebellum.