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Título

PICTORIAL ESSAY: MAGNETIC RESONANCE (MRI) FINDINGS OF PARTIALLY THROMBOSED GIANT INTRACRANIAL ANEURYSMS.

Introdução e objetivo(s)

Giant intracranial aneurysms (>2.5 cm in diameter) represent only 5-7% of all aneurysms. They can be saccular or fusiform and can affect the internal carotid artery (ICA) or the vertebrobasilar circulation. Most are related to
Extradural ICA within the cavernous sinus or middle cerebral artery (MCA), and a high incidence also in the apex of the basilar artery.
The important key to the diagnosis of a partially thrombosed giant aneurysm is the recognition of blood flow.
within the mass, which is pathognomonic of the entity.
GOALS:
Know the diagnostic methods used for the evaluation of partially thrombosed giant aneurysms.
Identify the characteristic findings on MRI.

Método(s)

A review of 5 cases of giant thrombosed intracranial aneurysms was carried out, looking for the characteristics that bring us closer to the diagnosis, analyzing the differential diagnoses and comparing them with what is described in the literature.

Discussão

Aneurysms are most commonly caused by atherosclerosis. They are most frequently found in middle-aged women and generally present with signs of a massive lesion, but subarachnoid hemorrhage (SAH) occurs. Therefore, the clinical presentation is usually related to compression of surrounding structures.
Tomography (CT) and Angiotomography (CTA) are ideal imaging modalities in the initial evaluation of partially thrombosed giant aneurysms, allowing global appreciation and identification of wall or neck calcifications.
Due to their dual component nature (thrombosed portion with layered clot and portion with blood flow), these aneurysms have a typical appearance on MRI: Flow phenomena/rapidly flowing blood within the permeable portion of the lumen (usually appearing as a flow void). Laminated thrombus of mixed stages in the coagulated portion of the lumen. Recognition of the anatomical relationship of null signal in the original vessel.
In the review of patients that we carried out, we were able to identify these characteristic factors of MRI.

Conclusões

MRI is useful for the characterization of thrombosed aneurysms by observing the turbulent flow inside them and the correlation with adjacent structures.
The location, signal, post-contrast behavior and the relationship with adjacent structures are the keys to reaching the correct diagnosis.

Palavras Chave

PARTIALLY THROMBOSED ANEURYSM

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