Neurovascular Cases

What’s the diagnosis?

There is a nearly 2 cm left internal carotid artery terminus dysplastic aneurysm that incorporates the origins of both the middle cerebral and anterior cerebral arteries on that side. There is also an occlusion of the left middle cerebral artery just proximal its bifurcation. The endovascular pathway, or route to the occlusion is through this large, unruptured aneurysm.

Differential Diagnosis

  1. In patients with intracranial aneurysms and an acute neurological decline, subarachnoid hemorrhage due to aneurysmal rupture must be considered. In this case, a non-contrast CT head scan on presentation did not show any subarachnoid hemorrhage or intra-parenchymal blood products to suggest aneurysmal rupture as the cause of the patient’s symptoms.


  • Giant intracranial aneurysms are defined as having a diameter of at least 25 mm.
  • Patients with giant intracranial aneurysms commonly present with subarachnoid hemorrhage or local mass effect, but thromboemboli from these aneurysms or other large aneurysms can cause transient ischemic attacks or strokes.
  • The Law of LaPlace states that wall tension increases with aneurysm diameter and in general, larger aneurysms carry a higher risk of rupture than smaller ones.
  • In the case of an acute large vessel occlusion, the potential benefits of endovascular thrombectomy must be weighed against the treatment risks. In this case, the risk of attempting endovascular thrombectomy is higher than normal because the aneurysm will need to be traversed in order to access the clot, and rupture of the aneurysm due to manipulation would be a catastrophic event.

What's your treatment plan?

  • Very few reported cases are available to guide clinical decision making in this scenario. Factors to consider include whether or not to administer tissue plasminogen activator to a patient with an unruptured intracranial aneurysm, whether or not to attempt endovascular thrombectomy and, if thrombectomy will be attempted, to devise a contingency plan should the aneurysm rupture.

In this case, stent retriever assisted manual aspiration thrombectomy was performed. To do this, a micro-wire was carefully steered from the internal carotid artery through the channels within the aneurysm and into the middle cerebral artery. A micro-catheter was tracked over this wire. A stent retriever device was deployed through the micro-catheter in the middle cerebral artery. The micro-catheter was removed and an aspiration catheter was tracked over the stent retriever while manual aspiration was applied. The stent retriever was withdrawn and then the aspiration catheter was withdrawn while vigorous manual suction was applied. The clot was removed and anterograde flow through the middle cerebral artery was restored.