Aneurysms in Twig-Like Middle Cerebral Artery

Rete middle cerebral artery presenting with a ruptured aneurysm

ABSTRACT

The developmental anomaly of the middle cerebral artery (MCA) is a rare occurrence. Rete MCA, also known as "unfused," "twig-like," and aplastic MCA, is an even rarer anomaly. These immature rete vessels are prone to flow-related aneurysms which rupture themselves presenting with intraparenchymal hematoma. We here with present a case of rete MCA with a ruptured aneurysm and discuss its pathophysiology and management.

Development of Collateral Vessels after Anterior Circulation Large Vessel Occlusion in Pediatric Arterial Ischemic Stroke Relates to Stroke Etiology: A Longitudinal Study

BACKGROUND AND PURPOSE

The characteristics of large vessel occlusion (LVO) in the acute phase of pediatric arterial ischemic stroke and their natural history according to stroke etiology are poorly explored. This studied aimed at describing the prevalence and the radiological evolution of LVO in pediatric AIS.

MATERIALS AND METHODS

This single-center retrospective study included consecutive non-neonate children with acute arterial ischemic stroke, intracranial proximal LVO in the anterior circulation (MCA, anterior cerebral artery, and/or ICA), and clinical and imaging follow-up for at least 18 months, during a 9-year period.

RESULTS

Intracranial LVO was observed in 24.8% of patients with anterior circulation arterial ischemic stroke and adequate follow-up (n = 26/105), with a median age of 4.2 years (IQR 0.8-9), sex ratio 1.16. The main stroke etiology associated with LVO was unilateral focal cerebral arteriopathy (n = 12, 46%). During follow-up, a specific pattern of unilateral poststroke anastomotic bridge was observed in 8/26 patients, with the poststroke development of nonperforating collaterals forming a bridge in bypass of the LVO site with visible distal flow, within a median delay of 11 months. The development of unilateral poststroke anastomotic bridge was only observed in patients with unilateral focal cerebral arteriopathy. No patient with this pattern experienced stroke recurrence or further progressive vascular modifications.

CONCLUSIONS

After stroke, the development of unilateral poststroke anastomotic bridge is specifically observed in children with focal cerebral arteriopathy, appearing in the first year after stroke. This clinical-radiologic pattern was not associated with stroke recurrence or arterial worsening, differentiating it from progressive intracranial arteriopathy, such as Moyamoya angiopathy.

Non-aneurysmal subarachnoid hemorrhage in aplastic or twig-like middle cerebral artery: A case report and literature review

BACKGROUND

Aplastic or twig-like middle cerebral artery (Ap/T-MCA) is a rare vascular anomaly that can cause hemorrhagic and ischemic stroke. Ap/T-MCA can induce aneurysms due to the fragility of the vessel wall, consequently leading to subarachnoid hemorrhage. Herein, we report a case of Ap/T-MCA with subarachnoid hemorrhage without an aneurysm.

CASE PRESENTATION

A 67-year-old man presented to our hospital with a sudden onset of headache. Computed tomography of the head revealed subarachnoid hemorrhage (SAH) in the left Sylvian fissure; however, no aneurysm was observed on digital subtraction angiography. Following conservative treatment, follow-up imaging showed no aneurysm or no recurrent stroke.

CONCLUSION

Non-aneurysmal SAH is a possible indication of vessel wall fragility in Ap/T-MCA; however, a standardized treatment strategy for this condition remains to be established.

Rete Middle Cerebral Artery Aneurysm: A Case Report and Systematic Review

Background  Middle cerebral artery (MCA) anomalies are a rare finding and may be associated with vascular changes, such as intracranial aneurysms. Among them, the rete MCA aneurysm is very rare, with only 22 cases reported to date. Case Description  A 50-year-old woman presented with subarachnoid, intraventricular, and intracerebral hemorrhage secondary to a ruptured aneurysm of rete MCA from an anomalous collateral artery of the anterior cerebral artery, treated successfully by microsurgical clipping. She presented a good recovery after a 2-year follow-up. Conclusion  A systematic review of rete MCA aneurysms is presented, comparing aneurysms originating from twig-like MCA, with 16 reports, and twig-like networks of an anomalous collateral artery, with 6 reports including ours. Several factors influence the treatment decision-making, though microsurgical clipping is the main procedure. A wider use of coiling is requested for a better comparison of the treatment approaches.

Unilateral rete mirabile in multiple intracranial arteries with ipsilateral agenesis of the internal carotid artery: a case report

BACKGROUND

Rete mirabile of the cerebral artery is a rare anomaly, with most previous cases occurring in the middle cerebral artery or internal carotid artery. Here, we present the first report of unilateral rete mirabile in multiple intracranial arteries with ipsilateral internal carotid artery agenesis.

CASE PRESENTATION

A 64-year-old Japanese woman was brought to the emergency department of our hospital in a deep coma. Computed tomography of the head showed severe intraventricular hemorrhage with subarachnoid hemorrhage. Computed tomography angiography showed not only congenital left internal carotid artery agenesis, but also rete mirabile of the left posterior communicating artery, the left posterior cerebral artery, and the left anterior cerebral artery. This unilateral vessel anomaly complex may have contributed to the formation of a peripheral aneurysm arising from a perforating branch of the pericallosal artery, which ruptured. The patient underwent urgent bilateral external ventricular drainage, but deteriorated and was declared brain dead.

CONCLUSIONS

We report the first case of unilateral rete mirabile in multiple intracranial arteries. Because the cerebral arteries in patients with rete mirabile may be vulnerable, close attention should be paid to the development of cerebral aneurysms.

De novo formation of twig-like middle cerebral artery: An illustrative case

Background

Twig-like middle cerebral artery (T-MCA) is a rare vascular abnormality characterized by the replacement of the M1 segment of the middle cerebral artery (MCA) with a plexiform arterial network of small vessels. T-MCA is generally regarded as an embryological persistence. Conversely, T-MCA may also be a secondary sequela but no reports of cases of de novo formation exist. Here, we report the first case describing possible de novo T-MCA formation.

Case Description

A 41-year-old woman was referred to our hospital from a nearby clinic because of transient left hemiparesis. Magnetic resonance (MR) imaging revealed mild stenosis of the bilateral MCAs. The patient then underwent MR imaging follow-ups once a year. MR imaging at the age of 53 showed a right M1 occlusion. Cerebral angiography revealed a right M1 occlusion and formation of a plexiform network consistent with the occlusion site, leading to the diagnosis of de novo T-MCA.

Conclusion

This is the first case report describing possible de novo T-MCA formation. Although a detailed laboratory examination did not confirm the etiology, autoimmune disease was suspected to have precipitated this vascular lesion.

Anterior cerebral artery dissection for a patient with ipsilateral aplastic or twig-like middle cerebral artery: An illustrative case report

Background

An aplastic or twig-like middle cerebral artery (Ap/T-MCA) is a rare anomaly, which sometimes causes ischemic infarction. Collateral flow from the ipsilateral anterior cerebral artery (ACA) is important for patients with Ap/T-MCA. If ipsilateral ACA stenosis or occlusion occurs, a large infarction with a wider field than the ACA territory could happen. First, mechanical thrombectomy was performed for the right ACA near occlusion caused by arterial dissection with ipsilateral Ap/T-MCA in this case. Second, Wingspan stenting was performed for the right ACA restenosis.

Case Description

A 77-year-old female presented to the hospital with the left hemiparesis. We diagnosed a right ACA infarction caused by right ACA occlusion. Digital subtraction angiography showed right Ap/T-MCA and ipsilateral ACA near occlusion. Thrombectomy was performed, and recanalization was achieved with mild ACA stenosis. The lesion was the dissection due to angiographical finding. Two months after treatment, transient left hemiparesis occurred and right ACA stenosis progressed. Computed tomography perfusion showed hypoperfusion of the right hemisphere. Wingspan stenting was performed from the left internal carotid artery through the anterior communicating artery with an intermediate catheter. The patient was discharged without any neurological deficit.

Conclusion

We reported the first case of a patient who underwent Wingspan stenting for the right ACA dissection with Ap/T-MCA. Short-term follow-up and aggressive intervention should be considered for collateral pathway dissection with Ap/T-MCA because the symptoms can become serious. The patients with Ap/T-MCA should be cautious about the collateral pathway arterial changes in particular ipsilateral ACA due to the increasing hemodynamic stress.

Case report: Endovascular coil embolization of an aneurysm at the origin of the accessory middle cerebral artery from the A1 segment as the collateral artery to twigs

An aneurysm at the origin of the accessory middle cerebral artery (AccMCA) from the A1 segment of the anterior cerebral artery (ACA) as the supplying artery of a twig-like MCA is exceptional. In this study, we reported on such a case and presented a review of the relevant literature. A 56-year-old male suffered a subarachnoid hemorrhage. Digital subtraction angiography confirmed a twig-like MCA and a ruptured aneurysm at the origin of the AccMCA. Endovascular coil embolization of the aneurysm was performed. After the microcatheter was positioned in the aneurysm, soft coils were delivered to complete the embolization. Postoperatively, the patient recovered uneventfully. One month later, the patient returned to his job without any neurological deficits. Postoperative computed tomography at the 3-month follow-up showed that the brain tissue was normal. By reporting our case and reviewing the relevant literature, we found that endovascular coil embolization for such aneurysms at the AccMCA origin is feasible in certain cases.

Cerebrovascular Treatment with Superselective Balloon Test Occlusion for Multiple Cerebral Aneurysms Associated with Middle Cerebral Artery Anomaly: A Case Report

A 38-year-old woman presented with impaired consciousness and anisocoria due to a subarachnoid hemorrhage and an intracerebral hemorrhage of the left temporal lobe. Examination revealed severe tortuosity in the left middle cerebral artery and three sequential bead-like aneurysms. She underwent a craniotomy in the acute phase to stop rebleeding at the rupture site and remove the intracerebral hematoma. During the chronic phase, endovascular treatment with superselective balloon test occlusion (ssBTO) was performed for the remaining aneurysms. Preoperative ssBTO was useful in evaluating collateral circulation and assessing the curability of the treatment.

A Ruptured Aneurysm in Aplastic or Twig-like Middle Cerebral Artery: A Case Report with Histological Investigation

Aplastic or twig-like middle cerebral artery (Ap/T-MCA) is a rare vascular anomaly that can cause a hemorrhagic or ischemic event. We report a 38-year-old man who presented with intracerebral hemorrhage from a ruptured aneurysm associated with an Ap/T-MCA. After aneurysm trapping and resection, histopathological examination revealed an internal elastic lamina (IEL) disruption and a thin aneurysmal wall. The patient recovered well after surgery and rehabilitation. No hemorrhagic or ischemic events have occurred during 2 years of follow-up. Ap/T-MCA-associated aneurysms exhibit a disrupted IEL and thin wall, which demonstrates the fragility of the “twig-like” vessels.

Aplastic or twig-like middle cerebral artery and cardiogenic cerebral embolism mimicking moyamoya disease with RNF213 polymorphism: A case report

Progressive stenosis and occlusion of the bilateral internal carotid artery terminals and circle of Willis are typical features of Moyamoya disease. However, aplastic or twig-like middle cerebral artery (Ap/T-MCA)-wherein the unilateral main trunk of the middle cerebral artery (MCA) is not depicted, and a plexiform arterial network is formed-is similar to the findings of Moyamoya disease. Here, we describe a 78-year-old man who presented with mild right paralysis and aphasia. Magnetic resonance angiography (MRA) at admission did not show the bilateral MCAs. The findings were similar to those of Moyamoya disease, and his symptoms worsened after hospitalization. Endovascular treatment was performed, and the left MCA was completely recanalized. Later, paroxysmal atrial fibrillation was detected, and we finally determined that left MCA occlusion had occurred due to embolism. The right MCA was completely occluded at its origin, indicating an Ap/T-MCA. Embolic occlusion of the unilateral MCA and contralateral Ap/T-MCA made this case resemble Moyamoya disease in the acute stage. Even when chronic occlusion is suspected on MRA in acute cerebral infarction, endovascular treatment should be considered. Additionally, a heterotypic R4810K polymorphism was later found in the RNF213 gene. To our knowledge, this is the second report of Ap/T-MCA with the RNF213 gene polymorphism; however, their association remains unclear and requires further analyses.

Ruptured aneurysm associated with a twig-like middle cerebral artery: An illustrative case report

Background:

Anomalies of the middle cerebral artery (MCA) are rare; among the different types of anomalies, the aplastic or twig-like (Ap/T) MCA is extremely rare and has been reported under various names, including aplastic, unfused, or rete type anomaly. The occurrence of a brain aneurysm associated with this anatomic variant is an even rare event, and probably their development and rupture are related to hemodynamic stress of the tinny wall of vessels forming the network.

Case Description:

We present a 43-year-old male patient with an explosive and persistent right orbitofrontal headache. A computed tomography showed a right frontobasal hematoma with intraventricular disruption. Magnetic resonance angiography showed a right MCA aneurysm and what seems to be a MCA trunk stenosis. Cerebral digital subtraction angiography demonstrated a plexiform arterial network and one aneurysm arising from the network. The patient was successfully treated by surgical clipping to evacuate the hematoma and to prevent further intracranial hemorrhages.

Conclusion:

The Ap/T-MCA may be associated with hemodynamic stress with a significant effect through the tinny wall of the vessels causing hemorrhage or leading to the formation and rupture of cerebral aneurysms. Based on a correct diagnosis of the anomaly, treatment can be completed successfully through different standard methods.

Three-Dimensional Angioarchitecture of Rete Middle Cerebral Artery Anomalies and the Clinical Significance

PURPOSE

Rete middle cerebral artery (MCA) anomaly is characterized by a web-like network of arteries involving the first MCA segment (M1) and a normal downstream MCA. The detailed composition of this anomaly and the hemodynamic impacts on cerebral perfusion are rarely addressed. The purpose of this study was to elucidate the anatomical and hemodynamic perspectives of the rete MCA anomaly.

METHODS

From August 2020 to December 2021, 4 rete MCA anomalies were identified at Shuang Ho hospital. Clinical information, perfusion magnetic resonance (MR) imaging, and angiographic images were collected. Detailed angioarchitecture, including types of arterial feeders and extent of rete involvement, were analyzed based on three-dimensional volume-rendering reconstruction images obtained from the catheter-based angiographies.

RESULTS

Despite their variable clinical presentations (two hemorrhage, one ischemia, and one asymptomatic), all cases shared common angiographic findings as follows: (1) the internal carotid artery did not connect directly to the rete, (2) the anterior choroidal artery (AChA) was the artery constantly supplying the rete and (3) there was a watershed zone shift toward MCA territory. The perfusion MR cerebral blood flow map was symmetric in all studied cases.

CONCLUSION

The AChA is an artery constantly supplying the rete, which suggests that the angioarchitectural features associated with this anomaly may be the result of both congenital and acquired compensatory processes. Cerebral perfusion remains preserved at the lesion side, despite angiographic evidence of watershed zone shift. These findings will be important for making better clinical judgments about this condition.

A case of cerebral infarction due to aplastic or twig-like middle cerebral artery after lung cancer surgery

Aplastic/twig-like middle cerebral artery is a rare vascular abnormality. We report a case of postoperative cerebral infarction caused by this disease. The patient is a male in his 40s. A 9-cm tumour was revealed to have invaded the superior vena cava from his right lung. He underwent right upper and middle bilobectomy. Due to the vascular invasion, the intraoperative bleeding exceeded 2 litres. Mechanical ventilation was required for postoperative pneumonia. After extubation, he was unable to write and was found to have cerebral infiltration in the left middle cerebral artery region. The cause of the cerebral infarction was investigated, but no thrombus in the left atrium or arteriosclerosis was found. No atrial fibrillation was observed during or after the surgery. Magnetic resonance angiography of the brain revealed an aplastic/twig-like middle cerebral artery.

Current state and confusion of twig-like middle cerebral artery

A twig-like middle cerebral artery (MCA) is an uncommon lesion in which a plexiform network of small vessels replaces the M1 segment of the MCA. Currently, we have insufficient information for twig-like MCAs. Therefore, a review of the literature using PubMed was conducted. In this review of twig-like MCAs, the following were discussed: the definition, pathogenesis, hemodynamics, associated aneurysm, clinical manifestations, imaging examinations, therapeutic strategies, therapeutic complications and prognosis. In addition, we proposed a reasonable grading system for twig-like MCAs, which is significant. For a twig-like MCA, the pathogenesis is unclear, and congenital and acquired factors can be involved. A twig-like MCA disturbed cerebral hemodynamics. An associated aneurysm can occur in patients with twig-like MCAs. Twig-like MCAs can present subclinically and without clinical symptoms, hemorrhage, or ischemic strokes. Of all the available imaging examinations, digital subtracted angiography is the gold standard. When treating a twig-like MCA, it is feasible to target the associated aneurysm, and extracranial-intracranial bypass can be effective in reducing the risk of strokes, but more evidence is needed. Now, the decision to perform surgery for twig-like MCAs should be made on a case-by-case basis.

Aplastic or twiglike middle cerebral artery with contralateral middle cerebral artery stenosis showing transient ischemic attack: illustrative case

BACKGROUND

Aplastic or twiglike middle cerebral artery (Ap/T-MCA) is a rare anomaly characterized by a unilateral MCA occlusion with plexiform vessels that causes hemorrhagic and (less commonly) ischemic strokes. The reasons for this are rarely discussed, and thus optimal treatment for ischemic Ap/T-MCA remains controversial. Here, the authors report a case of Ap/T-MCA with transient ischemic attacks treated by bypass surgery and discuss the mechanism of ischemic development and treatment methods.

OBSERVATIONS

A 62-year-old hypertensive man with transient, recurrent left hemiparesis visited the authors’ hospital. Magnetic resonance angiography showed proximal occlusion of the right MCA and stenosis in the left MCA. Digital subtraction angiography revealed occlusion of the right MCA and abnormal vascular networks, leading to a diagnosis of Ap/T-MCA with contralateral MCA stenosis. Antiplatelet therapy with aspirin was insufficient, and a superficial temporal artery–MCA bypass was performed. There were no ischemic or hemorrhagic events postoperatively.

LESSONS

Atherosclerosis seems to have a significant impact on the development of ischemic stroke in patients with Ap/T-MCA, and the presence of coexisting atherosclerotic stenotic vascular lesions outside the Ap/T-MCA site is substantial in its development. Bypass surgery is a promising treatment option for ischemic Ap/T-MCA.

Radiological and clinical features of twig-like middle cerebral artery in comparison with moyamoya angiopathy: a multicenter retrospective study

OBJECTIVE

Twig-like middle cerebral artery (T-MCA) is a rare congenital anomaly that is difficult to distinguish from moyamoya angiopathy (MMA), given the similarity of the angioarchitectures. The aim of this study was to gain insights into the radiological and clinical features of T-MCA and to distinguish this condition from MMA.

METHODS

A multicenter retrospective study was conducted in 29 patients with T-MCA and 57 patients with MMA. Demographic, radiological, and clinical data were compared between the patients with T-MCA and those with MMA.

RESULTS

The T-MCA group tended to be older than the MMA group (mean age 47 ± 18 vs 39 ± 22 years). Twenty patients with T-MCA (69%) were initially diagnosed with MMA. All T-MCA cases had twig-like networks and steno-occlusive changes involving the MCA. The T-MCA group had a higher incidence of intracranial aneurysms (35% vs 11%) and coexisting arterial anomalies (48% vs 12%). T-MCA and MMA cases had significant differences in involvement of the internal carotid artery terminus (0% vs 100%) and posterior cerebral artery (0% vs 23%), and in transdural anastomosis (0% vs 51%). T-MCA cases were less likely to present with stroke (59% vs 86%) and more likely to be asymptomatic (28% vs 12%). Of the patients with stroke, those with T-MCA had more hemorrhagic strokes (41% vs 29%) and fewer ischemic strokes (59% vs 71%) compared to those with MMA.

CONCLUSIONS

This study suggests that T-MCA is a different disease entity from MMA based on significant differences in the radiological and clinical features. Neurosurgeons should recognize this anomaly and understand the key features that differentiate T-MCA from MMA.

Moyamoya Vasculopathy: Cause, Clinical Manifestations, Neuroradiologic Features, and Surgical Management

In moyamoya disease, the progressive occlusion of the distal portion of the internal carotid artery and its major branches is typically responsible for the formation of an extensive network of collateral vessels at the base of the brain. When moyamoya collateral network develops in association with various systemic or acquired diseases, the term moyamoya syndrome is used to denote this phenomenon. Sudden changes in the supraclinoid internal carotid artery and middle cerebral artery can be recognized with noninvasive neurovascular imaging techniques, which also allow a differential diagnosis with similar diseases such as degenerative steno-occlusive disease, cerebral vasculitis, and twig-like middle cerebral artery. Once the diagnosis is established, the definitive treatment for moyamoya disease is surgical revascularization, with the goal of increasing cerebral blood flow and preventing recurrent stroke. We provide a comprehensive review of the clinical and radiologic features in moyamoya vasculopathy along with its surgical management.

A Case of Aneurysmal Subarachnoid Hemorrhage with Middle Cerebral Artery Aplasia at 30 Weeks of Pregnancy

Objective

We report a case of subarachnoid hemorrhage (SAH) that occurred at 30 weeks of pregnancy and was treated by coil embolization in a woman with middle cerebral artery (MCA) aplasia.

Case Presentation

A 40-year-old woman who was 30 weeks pregnant presented to the emergency department with a half-day history of headache and nausea. She had sudden onset headache and her symptom did not improve. There was no neurological deficit. Head CT at the referring hospital revealed SAH. The fetal state was stable. There was no sign of threatened premature delivery. Head MRA revealed aplasia of the left MCA and aneurysm with a daughter sac at the A1 segment of the anterior cerebral artery (ACA). Head DSA revealed that the A1 aneurysm with a daughter sac arose from the anomalous collateral artery leading to a plexiform network. The diagnosis was SAH due to rupture of an A1 aneurysm. Performance of less invasive coil embolization seemed to be possible and was carried out under general anesthesia. The operation was completed after placing one coil and confirming that most of the aneurysmal dome was embolized, including the daughter sac. There was no cerebral vasospasm and no obvious neurological deficit. Antiplatelet drugs were only required for 10 days after the operation. Pregnancy was stable and the patient delivered a baby by cesarean section at 38 weeks of pregnancy.

Conclusion

A rare case of aneurysmal SAH in a pregnant woman with MCA aplasia was successfully treated by endovascular surgery.

Aplastic or twig-like middle cerebral artery harboring unruptured cerebral aneurysms treated by clipping and bypass surgery: illustrative case

BACKGROUND

Aplastic or twig-like middle cerebral artery (Ap/T-MCA) is a congenital MCA anomaly. It may present with symptoms of both hemorrhage and ischemia, similar to moyamoya disease, and hemodynamic stress may play an essential role in the development of symptoms in both clinical entities. The optimal treatment remains controversial in symptomatic patients with Ap/T-MCA. This report discussed the treatment method for a patient with Ap/T-MCA with unruptured aneurysms who presented with intraventricular hemorrhage (IVH) treated by aneurysm clipping and bypass surgery.

OBSERVATIONS

In a 46-year-old woman with a sudden headache, computed tomography showed left IVH. Magnetic resonance angiography showed a left MCA aneurysm and MCA trunk stenosis. Three-dimensional angiography demonstrated a plexiform arterial network and multiple aneurysms arising from the MCA and in the plexiform network, leading to the diagnosis of Ap/T-MCA harboring unruptured aneurysms. The patient was successfully treated by craniotomy with aneurysm clipping and bypass surgery to prevent further intracranial hemorrhages and/or aneurysm rupture.

LESSONS

Especially in cases such as Ap/T-MCA, in which hemodynamic stress has a significant effect, the optimal treatment method should be based on vascular morphology and the impact of hemodynamic stress.

Mechanical Thrombectomy for ICA Top Occlusion with Twig-Like MCA: A Case Report

Objective

We report a case of hemorrhagic complication after mechanical thrombectomy (MT) for internal carotid artery (ICA) occlusion with twig-like middle cerebral artery (MCA).

Case Presentation

A 75-year-old man was admitted to our hospital with ICA occlusion. Recanalization was achieved by a direct aspiration first pass technique (ADAPT). The peripheral MCA was twig-like, but operators thought that a thrombus remained in the MCA first segment. The procedure was continued and suspended with perforation of the microguidewire.

Conclusion

When performing MT for large vessel occlusion (LVO) with twig-like MCA, it is difficult to proceed a device to the periphery and there is a risk of hemorrhage.

Rete middle cerebral artery: a rare association with anterior cerebral artery aneurysm rupture

Haemodynamic flow-related stress at the vessel curvatures is an important risk factor for intracranial aneurysmal growth and rupture. The rete middle cerebral artery (MCA) is a rare entity causing hyperdynamic blood flow into the ipsilateral anterior cerebral artery (ACA), especially when the contralateral A1-segment is non-dominant. Ruling out the clinicoradiological mimics like vasculitis, moyamoya and chronic occlusive disease with vessel wall imaging and detailed investigations helps manage the clinical entity effectively. We present a successfully managed case of ruptured ACA aneurysm at the acute curvature of the A1-A2 junction associated with ipsilateral rete MCA. Pre-emptive diagnosis of the rete MCA can aid preventive strategies to manage rupture and regrowth of the aneurysm at the points of flow-related stress.

Preventive Effect of Bypass Surgery on Rebleeding in Patients with Hemorrhagic Twiglike Middle Cerebral Artery

BACKGROUND

Aplastic or twiglike middle cerebral artery (Ap/T-MCA) is a rare cerebrovascular anomaly correlated to stroke. The most common characteristic of the disease is intracerebral hemorrhage. However, treatment measures that can prevent rebleeding have not yet been established.

OBJECTIVE

We sought to validate whether extracranial-intracranial (EC-IC) bypass is effective in preventing recurrent intracerebral hemorrhage in patients with Ap/T-MCA.

METHODS

Ap/T-MCA was defined on the basis of the following criteria: 1) M1 occlusion with plexiform vessels, 2) unilateral MCA involvement without progression to the contralateral side, 3) no significant stenosis in the M2 segment, and 4) no stenoocclusive lesions in other intracranial major arteries. The clinical features, surgical procedures, radiologic changes, and treatment outcomes of patients with Ap/T-MCA who presented with ipsilateral intracerebral hemorrhage at our institution from April 2004 to December 2019 were retrospectively reviewed.

RESULTS

Seven patients fulfilled the criteria for hemorrhagic Ap/T-MCA. Female preponderance was observed, and the mean age at the time of onset was 38 (range: 28-47) years. Three patients presented with pure intraventricular hemorrhage and 4 with intraparenchymal hemorrhage. Of the 4 patients, 2 had intraventricular extension. All patients underwent EC-IC bypass and did not present with stroke during the follow-up period (median: 36 [range: 5-140] months). Follow-up magnetic resonance imaging revealed regression of the twiglike vessels or periventricular choroidal anastomosis within 1 year after surgery in all patients.

CONCLUSIONS

EC-IC bypass may be a treatment option that can prevent rebleeding in patients with hemorrhagic Ap/T-MCA.

Twig-like middle cerebral arteries: Clinical and radiological findings

BACKGROUND AND PURPOSE

Aplastic or twig-like middle cerebral artery (MCA) is a rare vascular anomaly characterized by replacement of the M1 segment by a plexiform network of small vessels. Though rare, familiarity with this entity and ability to differentiate it from radiological mimics such as moyamoya changes and steno-occlusive diseases are important. We review the clinical and radiological manifestations of patients diagnosed with twig-like MCA on cerebral angiograms over a five-year period.

MATERIALS AND METHODS

Retrospective review of all patients diagnosed with twig-like MCA on cerebral angiograms was performed from January 2015 to January 2020. This was the inclusion criterion for this retrospective study. For each patient, demographic data, clinical presentation, imaging findings and management strategies were reviewed.

RESULTS AND CONCLUSIONS

Between January 2015 and January 2020, three patients with twig-like MCA were identified from 657 patients who underwent four-vessel diagnostic cerebral angiograms (0.45%). In all three cases, the involvement was unilateral (two left-sided and one right- sided). Two patients were male, and one was female. Patients ages were 25, 26 and 46 years. Two of the three patients presented with headache and the third patient with pulsatile tinnitus. There were otherwise no ischemic or hemorrhagic changes. No other vascular anomaly was identified. Twig-like MCA is a rare anatomical variant in which a plexiform network of small vessels replaces the M1 segment of the MCA. Accurate diagnosis and distinguishing this entity from radiological mimics such as moyamoya and steno-occlusive diseases are important for appropriate management and to prevent unnecessary investigations.

Hemorrhagic events associated with unfused or twig-like configuration of the Middle cerebral artery: A rare vascular anomaly with clinical relevance

INTRODUCTION

Twig-like middle cerebral artery configuration (Tw-MCA) is a rare and commonly misdiagnosed vascular anomaly characterized by a plexiform arterial network that replaces the normal M1 segment. The prevalence and clinical relevance of this anomaly is not fully established.

MATERIAL AND METHODS

We sought to explore the prevalence of Tw-MCA in patients clinically referred to digital angiography in a single academic comprehensive endovascular center and evaluated the radiological and clinical findings among patients with hemorrhagic events.

RESULTS

From 2011 to 2020, a total of 10,234 patients underwent a cerebral angiography at our institution. During this period, 9 (0.088%) Tw-MCAs were identified. Out of these, 5 patients (62.5%) were admitted due to an intracranial hemorrhage. Two patients had a ruptured intracranial aneurysm on the anterior communicating artery, one with multiple brain aneurysms; two patients presented an intraparenchymal hematoma (IPH) due to the presence of a periventricular anastomosis and one patient an intraventricular hemorrhage with unclear origin.

CONCLUSION

Tw-MCA is a very rare vascular anomaly associated with hemorrhagic events. Adequate identification of this anomaly is essential in order to avoid misdiagnosis as steno-occlusive disorders.

Rete middle cerebral artery anomalies: a unifying name, case series, and literature review

OBJECTIVE

Rete middle cerebral artery (MCA) is extremely rare and has not been frequently discussed. Rete MCA is a weblike anomaly of the MCA that does not coalesce and forms a prominent, large single branch from the plexiform vessels in the fetal stage. The purpose of this study was to further elucidate the clinical and radiological characteristics of patients with rete MCA.

METHODS

A total of 2262 cerebral digital subtraction angiography procedures were performed on 1937 patients at the authors' institution from February 2013 to May 2017. Data analysis included age, sex, clinical symptoms, underlying diseases, coexisting cerebral arterial anomalies, and operative methods and findings.

RESULTS

Rete MCAs were found in 13 patients, and the incidence of this anomaly was 0.67% (13 of 1937) in this study. Of the 13 patients, 3 had hemorrhagic strokes, 6 had ischemic strokes, and 4 had no symptoms. Eight patients underwent conservative treatment, and 5 patients underwent surgical treatment. Rete MCA is considered a congenital disease of the cerebral vasculature with the possibility of an acquired abnormality, such as an aneurysm, caused by hemodynamic stress. Although an epidemiological survey of rete MCA was not conducted, it is assumed that rete MCA has a high prevalence in Asia. Ischemic and hemorrhagic stroke events are fairly common in rete MCA.

CONCLUSIONS

Clinicians should understand the radiological and clinical features of patients with rete MCA to avoid misdiagnosis and unnecessary treatment. This anomaly should be differentiated from other vascular diseases and patients presenting incidentally should be carefully monitored because of their vulnerability to both hemorrhagic and ischemic strokes.

Subarachnoid Hemorrhage Attributable to Bilateral Aplastic or Twiglike Middle Cerebral Artery

BACKGROUND

Aplastic or twiglike middle cerebral artery (MCA), a congenital anomaly related to the abnormal development of the MCA, is rare. It is usually unilateral; bilateral lesions are extremely rare. An aplastic or twiglike MCA may lead to cerebral ischemic stroke, intracranial hemorrhage, and subarachnoid hemorrhage (SAH). In patients with ischemic stroke due to hemodynamic stress, extracranial-intracranial (EC-IC) bypass surgery is indicated. As hemodynamic stress may also elicit SAH, it is important to select the appropriate treatment. EC-IC bypass surgery was successful in a patient with bilateral aplastic or twiglike MCA who suffered SAH due to hemodynamic stress.

CASE DESCRIPTION

A 64-year-old female with a history of surgery for tetralogy of Fallot experienced SAH in the left sylvian fissure. As angiography showed a bilateral aplastic or twiglike MCA and single photon emission computed tomography revealed a decrease in the cerebral blood flow in the left MCA territory, we attributed her SAH to hemodynamic stress due to the decreased blood flow in the MCA territory and to the vulnerability of abnormal vessels as are seen in moyamoya disease. We performed EC-IC bypass surgery to reduce hemodynamic stress. A cerebral angiogram obtained 2 weeks postoperatively revealed sufficient blood flow in the MCA territory from the superficial temporal artery used for bypass. In the course of 2-year follow-up she remained stroke free.

CONCLUSIONS

The presence of aplastic or twiglike MCA may lead to stroke due to hemodynamic stress. EC-IC bypass surgery may help to prevent stroke recurrence and SAH.

Aplastic or Twig-Like Middle Cerebral Artery Presenting with Intracerebral Hemorrhage During Pregnancy: Report of Two Cases

Background

An aplastic or twig-like middle cerebral artery (Ap/T-MCA) is a rare congenital anomaly that can present with both ischemic and hemorrhagic stroke. The etiology of this pathology has remained unclear. Here, we report 2 cases of intracerebral hemorrhage (ICH) owing to an Ap/T-MCA in pregnant patients.

Case Description

In both patients, cerebral angiography revealed a steno-occlusive lesion and an abnormal arterial network on the unilateral middle cerebral artery. One patient was treated conservatively for a putaminal hemorrhage, and a cesarean section was performed uneventfully 6 months after onset of the ICH. The other patient underwent a craniotomy for evacuation of the lobar hemorrhage. Subsequently, a cesarean section was performed uneventfully. Both patients gradually recovered without significant disabilities.

Conclusions

An Ap/T-MCA is a rare congenital anomaly and is a potential cause of ICH for pregnant patients. A cesarean section is a useful option for pregnant patients with this condition.

Anomalies of the Middle Cerebral Artery

There are several anomalies of the middle cerebral artery (MCA) in humans, such as accessory MCA, duplicated MCA, fenestration of MCA, and duplicated origin of MCA. Recently, unfused or twig-like MCA, which indicates MCA trunk occlusion with collateral plexiform arterial network, have been reported. During the embryonic stage, MCA is thought to generate from plexiform arterial twigs arising from the anterior cerebral artery, and these twigs form the definitive MCA by fusion and regression at the end of the development stage. Any interruption during the fusion of the arterial twigs may result in MCA anomalies, and the unfused or twig-like MCA, especially, is hypothesized to be the persistent primitive arterial twigs. Clinically, it is challenging to differentiate the unfused or twig-like MCA from unilateral moyamoya disease, in which stenotic change begins at the MCA. The knowledge of the anomalies of the MCA is important to perform a safe surgical or endovascular intervention.

Endovascular management of a collateral network aneurysm in a patient with spontaneous internal carotid artery occlusion

Spontaneous "non-moyamoya" arterial occlusion of the intracranial arteries is very unusual. Progressive occlusion of a major intracranial artery, independently from the etiology, can lead to the development of collateral arterial networks that supply blood flow to distal territories beyond the occlusion. These collateral arteries are typically small and conduct low flows, but the hemodynamic stress within them can lead to aneurysm formation within the collateral network. In this report we present a case of spontaneous internal carotid artery occlusion and collateral network aneurysm for the first time in the literature and discuss the main features of the etiology and endovascular treatment of this rare, challenging aneurysm.

A ruptured aneurysm located at a collateral artery that extended from the proximal A2 segment to the M1 segment, associated with an anomalous branch of the anterior choroidal artery and middle cerebral artery hypoplasia: case report

We here describe the first case of a ruptured aneurysm located at a collateral artery that extended from the proximal A2 segment to the M1 segment, which was associated with an anomalous branch of the anterior choroidal artery and middle cerebral artery (MCA) hypoplasia. The aneurysm was revealed by angiograms and intraoperative findings. No previous accounts have been published of such an extremely rare vessel anomaly. In practice, this case highlights the urgent need to preoperatively recognize such vascular anomalies, as well as to better understand the collateral blood supply in cerebral ischemia associated with these MCA anomalies. Such knowledge will be helpful for planning optimal surgical procedures.

Two different morphologies of chronic unilateral middle cerebral artery occlusion: evaluation using high-resolution MRI

INTRODUCTION

Characterizing the morphologies of occluded artery segments may help elucidate the etiology of chronic intracranial artery occlusion. We acquired high-resolution MRI (HR-MRI) of the middle cerebral artery (MCA) in patients with chronic unilateral MCA occlusion and evaluated the MRI and clinical findings.

METHODS

We selected 20 consecutive patients who presented with unilateral MCA occlusion. Proton-density weighted HR-MRI of the occluded MCA was acquired using a 3.0 Tesla MRI. We surveyed the morphology of the MCA at the occluded segment. Symptoms, the presence of other stenotic arteries, and atherosclerosis risk factors were compared for patients grouped by different findings on HR-MRI.

RESULTS

MCA occlusions were classified into the following two groups: plugged MCA (13/20) with a clear view of the MCA trunk or vanishing MCA (7/20) with no MCA trunk visible in the Sylvian cistern. The presence of other stenotic arteries was more frequent in the plugged MCA group than in the vanishing MCA group.

CONCLUSIONS

HR-MRI can characterize the morphology of pathologic segments of chronic unilateral MCA occlusions in vivo. In chronic MCA occlusion, morphological analysis using HR-MRI may enhance the effort to assess the etiology in company with the angiographic finding.

Arterial stiffness using cardio-ankle vascular index reflects cerebral small vessel disease in healthy young and middle aged subjects

AIM

The cardio-ankle vascular index (CAVI) reflects overall arterial stiffness from the aorta to the ankle, independent of blood pressure. Cerebral small vessel diseases (SVDs), including white matter lesions (WML), silent lacunar infarction (SLI) and cerebral microbleeds (CMB), are considered to increase the risk of stroke and cognitive impairment further. We aimed to investigate the association of cerebral SVD with CAVI in asymptomatic young and middle-aged subjects.

METHODS

Asymptomatic Korean individuals aged 30 to 59 years old without neurologic disease who had CAVI and brain magnetic resonance imaging (MRI) were evaluated retrospectively.

RESULTS

Among 484 subjects, cerebral SVDs (advanced WML, SLI and CMB) were found in 20 (4.1%). Subjects with SVDs tended to be older and to have higher systolic blood pressure (SBP) and higher CAVI. From multivariate regression analysis, including pulse pressure (PP) or SBP, CAVI showed a significant association with SVD [adjusted OR (95% CI): 1.889 (1.094-3.263), p= 0.002 and 1.793 (1.020-3.153), p= 0.043, for PP and SBP, respectively]. When CAVI was assessed by quartiles, the highest quartile of CAVI (CAVI >7.65) showed a significant association with SVD, after adjustment for PP [adjusted OR (95% CI): 2.766 (1.115-6.866), p= 0.028].

CONCLUSION

In young and middle-aged subjects, cerebral SVD was significantly associated with arterial stiffness measured by CAVI after adjusting for PP or SBP.

Clinical and Radiological Features of Patients With Aplastic or Twiglike Middle Cerebral Arteries

BACKGROUND:

An aplastic or twiglike middle cerebral artery (Ap/T-MCA) is an extremely rare congenital anomaly related to interference in the normal embryonic development of the MCA.

OBJECTIVE:

To evaluate the clinical and radiological features of patients with an Ap/T-MCA.

METHODS:

A total of 1749 conventional cerebral angiography procedures were performed in 1282 patients from January 2005 to July 2011 at Daegu Fatima Hospital. The images were evaluated for cerebral arterial anomalies. The radiological features of an Ap/T-MCA, coexisting anomalies, and clinical manifestations were recorded. These prospectively maintained databases were analyzed retrospectively.

RESULTS:

Ap/T-MCAs were found in 15 patients (1.17% angiographic incidence). The anomalies were confined to unilateral M1 segment, and no stenoses were seen in the adjacent major arteries. Of 15 patients, 6 (40%) had hemorrhagic strokes, 5 (33.3%) had ischemic strokes, and 4 (26.7%) had no symptoms. Aneurysms were found in 5 patients (33.3%). Coexisting cerebral arterial anomalies were seen in 12 patients (80%). Ten patients underwent conservative treatments, and the remaining 5 underwent surgical treatments, such as hematoma aspiration, indirect revascularization, and clipping or coiling of aneurysms.

CONCLUSION:

An Ap/T-MCA is a rare anomaly and should be differentiated from moyamoya conditions and degenerative steno-occlusive diseases of the middle cerebral artery. Coexisting anomalies of the anterior or middle cerebral arteries are frequent. This anomaly is vulnerable to both hemorrhagic and ischemic strokes.

Advanced coronary artery calcification and cerebral small vessel diseases in the healthy elderly

BACKGROUND

Coronary artery calcification (CAC) scores are widely accepted to predict risk of coronary heart diseases and are associated with atherosclerosis in other vasculatures. Cerebral small vessel diseases (SVDs), including white matter lesions (WML), silent lacunar infarction (SLI) and cerebral microbleeds (CMB), are considered to develop in conjunction with pro-atherogenic conditions, measured by CAC scores.

METHODS AND RESULTS

Of 672 individuals aged ≥65 years that underwent health screening, 312 subjects with brain magnetic resonance imagings (MRIs) were enrolled in this study. The distribution of baseline characteristics among individuals with or without MRIs was not different. Clinical and laboratory information was collected and CAC scores were measured using multi-detector computed tomography. Cerebral SVD were independently assessed by 2 raters who were unaware of the CAC scores. The prevalence of CAC (CAC>0) was 71.7% in men and 50.0% in women. The associations between moderate-to-extensive CAC (CAC score ≥100) and WML (adjusted odds ratio and 95% confidence interval, 4.99 and 1.33-18.73), SLI (5.04 and 1.86-13.63) and CMB (6.07 and 1.54-23.94) remained significant after adjusting for relevant confounders.

CONCLUSIONS

This study documents significant associations between CAC and cerebral SVDs. The findings suggest that SVDs in the brain and CAC in the heart may develop under similar systemic pathogenic processes.