Başlık
Blood blister-like aneurysms (BBAs) include arterial lesions from non-branching sites (dorsal or anterior wall) on the internal carotid artery (ICA) . Although there have been descriptions of BBAs located at other sites within the intracranial circulation , the initial and most classic definition of a BBA is restricted to the ICA. They are particularly rare, representing approximately 0.9–6.5% of all ICA aneurysms , 1% of all intracranial aneurysms, and 0.5–2% of all ruptured aneurysms . These lesions were first described in the late 1970s , but the term “blister” was introduced in 1988 by Takashi. Patients typically present with acute subarachnoid hemorrhage (SAH), and the affected population is younger than patients with saccular aneurysms . Some authors have reported a female predominance, a right-sided ICA predominance and an association with hypertension . The classical morphology is small, hemispherical-shaped and bulging from non-branching sites on the ICA . They are typically diagnosed after a bleed because their small size allows them to be frequently missed on the first computed tomography angiogram (CTA) or even on the first digital subtraction angiogram (DSA). Special attention must be paid to the radiological evolution of a BBA after rupture because its progression to a saccular shape can be seen up to several days after the bleed.