Anomalous location of intracranial vessels in adults.

Anomalous intracranial vessels are not uncommon, and this finding is not always associated with arteriovenous malformations. Other conditions such as anomalous connections between arteries or phlebitc patterns can also present as vessels with abnormal intracranial locations. Noninvasive diagnosis is important to determine whether to do more invasive tests such as cerebral digital subtraction angiography or to estimate the risk of bleeding in arteriovenous malformations and therefore to evaluate the need for endovascular/surgical treatment. In this paper, we present an algorithm for the differential diagnosis of anomalous intracranial vessels according to their location (intra/extra-axial) and function (whether the vessels are arterialized). Moreover, we analyze the important points of the angioarchitecture of the principal arteriovenous malformations with risk of intracranial bleeding, such as pial arteriovenous malformations and dural fistulas.