Distal stump of an occluded intracranial vertebral artery at the vertebrobasilar junction mimicking a basilar artery aneurysm

Unraveling cerebral saccular aneurysm mimics: Case report and review of the literature

Introduction

Aneurysm mimics, such as an occluded cerebral artery, vascular loops or infundibular dilatations, should be beard in mind when planning a craniotomy for the treatment of an aneurysm. Although ischemic stroke caused by clot migration from an aneurysmal cavity has been described, an ischemic event should raise awareness of potential MCA branch occlusion instead of an aneurysm.

Research question

We provided a scaffold that could be used to differentiate other saccular aneurysm mimics. We explored the current literature concerning ACM segment occlusions initially misdiagnosed as a saccular aneurysm.

Material and methods

We present the case of a 58 year old female who experienced a subarachnoid hemorrhage. CT angiography could not reveal an underlying aneurysm. She had a medical history of right carotid artery occlusion with secondary ischemic stroke and left spastic hemiparesis. An aneurysm of the right MCA was suspected and she was scheduled for explorative craniotomy.

Results

Peroperatively we did not encounter an aneurysm, although a thrombosed branch of the right MCA was noted. The most proximal part of the branch was still patent, mimicking a saccular aneurysm on angiographic records.

Discussion and conclusion

Aneurysm mimics can potentially expose patients to unnecessary exploratory craniotomies in the presumptive diagnosis of a saccular aneurysm. MRI 3D-CISS can be a helpful adjunct, since MRA and DSA are frequently not sufficient. Although ischemic stroke can be caused by clot migration from an aneurysmal cavity, an ischemic event should raise awareness of potential cerebral artery occlusion.

Occlusion of the Anterior Cerebral Artery Mimicking a Cerebral Aneurysm: Clinical Presentation and Literature Review

BACKGROUND

 Intracranial aneurysms may be misdiagnosed with other vascular lesions such as vascular loops, infundibulum, or the stump of an occluded artery (very rare and reported compromising only the middle cerebral artery and the posterior circulation territory). Our aim was to describe a unique case of occlusion of an anterior cerebral artery mimicking a cerebral aneurysm in a probable moyamoya disease patient, and to highlight its clinical presentation, diagnosis, and management, and to perform an extensive literature review.

CASE

 A 67-year-old man suffering from recurrent dizziness for 3 months. Previous medical history was unremarkable. Brain magnetic resonance angiography (MRA) and digital subtraction angiography (DSA) demonstrated occlusion of the right middle cerebral artery (MCA) associated with a "probable moyamoya disease" and an aneurysm-like shadow protruding lesion at the anterior communicating artery (AcomA). Perfusion images showed ischemia along the right temporo-occipital lobe. Due to MCA occlusion with perfusion deficits and unspecific symptoms, we offered a right side encephalo-duro-myo-synangiosis (EDMS) and clipping of the AcomA aneurysm in one session. Intraoperatively, there was no evidence of the AcomA aneurysm; instead, this finding corresponded to the stump of the occluded right anterior cerebral artery (A1 segment). This segment appeared to be of yellowish color due to atherosclerosis and lacked blood flow. The patient underwent as previously planned a right side EDMS and the perioperative course was uneventful without the presence of additional ischemic attacks.

CONCLUSION

 Arterial branch occlusions can sometimes present atypical angiographic characteristics that can mimic a saccular intracranial aneurysm. It is relevant to consider this radiographic differential diagnosis, especially when aneurysm treatment is planned.

Republished: MRI SPACE sequence confirmation of occluded MCA M2 dissection stump masquerading as a ruptured MCA aneurysm

Intracranial vascular pathologies often have overlapping clinical presentations. Dissected vessel occlusions and bifurcation aneurysms can appear similar on pretherapeutic imaging. The medical management of these two entities is drastically different. The patient is a 51-year-old man who presented with severe, sudden-onset headache. Initial presentation was consistent with a ruptured middle cerebral artery (MCA) aneurysm and surgical clipping was recommended. However, further review of radiographic findings could not definitively differentiate an aneurysmal origin of the symptoms as opposed to intracranial dissection followed by occlusion of the M2 branch of the MCA. MRI sampling perfection with application optimised contrasts using different flip angle evolution (SPACE) was performed and showed thin flow signalling distal to the dissected vessel stump confirming the diagnosis. Accurate diagnosis is a crucial step in directing treatment for intracranial vascular lesions. MRI SPACE is a simple tool in the diagnostic armamentarium to adequately direct treatment and avoid the potential for unnecessary interventions.

MRI SPACE sequence confirmation of occluded MCA M2 dissection stump masquerading as a ruptured MCA aneurysm

Intracranial vascular pathologies often have overlapping clinical presentations. Dissected vessel occlusions and bifurcation aneurysms can appear similar on pretherapeutic imaging. The medical management of these two entities is drastically different. The patient is a 51-year-old man who presented with severe, sudden-onset headache. Initial presentation was consistent with a ruptured middle cerebral artery (MCA) aneurysm and surgical clipping was recommended. However, further review of radiographic findings could not definitively differentiate an aneurysmal origin of the symptoms as opposed to intracranial dissection followed by occlusion of the M2 branch of the MCA. MRI sampling perfection with application optimised contrasts using different flip angle evolution (SPACE) was performed and showed thin flow signalling distal to the dissected vessel stump confirming the diagnosis. Accurate diagnosis is a crucial step in directing treatment for intracranial vascular lesions. MRI SPACE is a simple tool in the diagnostic armamentarium to adequately direct treatment and avoid the potential for unnecessary interventions.

Occluded middle cerebral artery vascular stump mimicking aneurysm: case report and review of literature

The stump of an occluded middle cerebral artery (MCA) is a rare but important aneurysm mimic. A 57-year-old male was admitted due to recurrent onset of transient ischemic attack. Computed tomography angiography (CTA) and digital subtraction angiography (DSA) showed a total obstruction in the right MCA with moyamoya phenomenon at distal trunks and a protruding lesion in the left MCA bifurcation. The patient was diagnosed with left MCA bifurcation aneurysm. Intraoperatively, the lesion was found to be an occluded right MCA stump. Encephalomyoarteriosynangiosis was performed, and the patient remained symptom-free at the 6-month follow-up. The possibility of a vascular stump should be considered when an aneurismal lesion is present at the MCA bifurcation with moyamoya phenomenon at distal trunks.

Diagnosis of anterior inferior cerebellar artery occlusion on magnetic resonance angiography with reference to basiparallel anatomic scanning-magnetic resonance imaging

A 67-year-old woman presented with symptomatic infarction in the territory of the anterior inferior cerebellar artery manifesting as vertigo, vomiting, and right facial weakness. Basiparallel anatomic scanning (BPAS) magnetic resonance (MR) imaging combined with MR angiography demonstrated the occluded anterior inferior cerebellar artery. Common anatomic variations and limited detection of the smaller branches on MR angiography sometimes hinder evaluation of the occluded artery. BPAS-MR imaging may have a supplementary role to MR angiography in the diagnosis of cerebellar artery occlusions.

Angiographic pitfall: duplicated tapered A1 segment of the anterior cerebral artery mimicking an anterior communicating artery aneurysm

We describe a misleading case of a partially occluded A1 segment duplication that mimicked an ACoA aneurysm on computed tomography angiography and conventional angiography and led to surgical intervention. The location of such an anomaly at the ACoA on the side of least hemodynamic stress may provide a clue to recognizing this variant.

Middle cerebral artery branch occlusion mimicking a saccular aneurysm on 3D digital subtraction angiography

The angiographic appearance of an intracranial arterial occlusion is typically distinct from that of a saccular aneurysm, with only a few reported cases of occlusion simulating aneurysm. At the same time, a small percentage of symptomatic intracranial aneurysms present with a stroke. Accurate diagnosis of these conditions is crucial, as their treatment differs. The authors report on a case of middle cerebral artery occlusion that mimicked the appearance of an aneurysm on angiography in the setting of acute stroke. The true diagnosis was not elucidated until repeated angiography 6 months later revealed recanalization of the previously occluded middle cerebral artery branch. This angiographic pitfall is important to consider when acute stroke is suspected as the mode of presentation of a saccular aneurysm.

Occlusion of the middle cerebral artery branch mimicking aneurysm

A 26-year-old man was admitted to our department due to intermittent left hemiparesis for 3 months. Magnetic resonance image showed subacute infarction in the right precentral gyrus. Digital subtraction angiography and magnetic resonance angiography revealed an aneurysmal protrusion at the right middle cerebral artery (MCA) bifurcation. It was difficult to differentiate the aneurysm from the occlusion of the middle trunk of the MCA trifurcation. Brain single photon emission computerized tomography showed a decrease in perfusion in the right posterior frontal lobe without vascular reserve. Therefore, we planned a superficial temporal artery-MCA anastomosis with an exploration of the right MCA bifurcation. Intraoperatively, the aneurysmal opacification on preoperative angiography proved to be the proximal stump of the occluded middle trunk of the MCA trifurcation. An aneurysmal protrusion at the MCA bifurcation does not always indicate an aneurysm. In diagnosing protruding vascular lesions at the MCA bifurcation, the possibility of a vascular stump should be considered according to their angioanatomical appearance and the history of the patient.