Endovascular treatment of intracranial aneurysms associated with moyamoya disease or moyamoya syndrome

Effect of moyamoya disease on the basilar artery and adjacent arteries on CTA

Background

Computed tomographic angiography (CTA) is rarely used to explore the effect of moyamoya disease (MMD) on the basilar artery (BA) and its adjacent arteries.

Methods

Participants were divided into a control group and an MMD group. The relevant parameters were measured. Statistical analyses included the t-test, chi-squared test, and linear regression analysis.

Results

In the control group of 100 healthy people, the average age was 54.51 ± 13.40 years, and the ratio of males to females was 0.89:1. In the MMD group of 100 patients, the average age was 53.95 ± 11.31 years, and the ratio of males to females was 1.13:1. In the MMD group, the CTA score of the anterior circulation of the bilateral hemispheres was 7.57 ± 2.36. According to the statistical analyses, (1) in the control group, the BA apex tended to lean to the right in healthy participants; (2) in the MMD group, the BA was closer to the midline, and the angle between the BA and anterior inferior cerebellar artery was reduced, indicating that the BA was relatively elevated; (3) in the MMD group, the diameters of the BA, PCA and vertebral artery were larger than those in the control group; and (4) MMD patients with posterior cerebral atery (PCA) involvement had higher CTA scores of the anterior circulation.

Conclusions

MMD can cause the BA to move toward the midline and upward and enlarge major vessels of the posterior circulation. The PCA tends to be involved in MMD patients with higher CTA scores in the anterior circulation.

Risk factors of rupture and mortality for intracranial aneurysms associated with moyamoya disease: a multicenter retrospective study

OBJECTIVE

The aim of this study was to analyze the risk factors for aSAH and subsequent death in patients with MMD.

METHODS

Chinese Multi-Center Cerebral Aneurysm Database (CMAD) is a multicenter study registered in China. From 2016 to 2021, 181 patients with MMD in CMAD. Logistic regression analysis was used to identify risk factors for intracranial aneurysm rupture. Univariate and multivariate Cox regression were used to risk factors associated with ruptured intracranial aneurysm patients with MMD follow-up events (death). Cumulative survival was described using the Kaplan‒Meier technique.

RESULTS

Of 11,686 IA patients, 181 (1.5%) had MMD. In the study, 158 patients with MMD were enrolled. There were 53 ruptured aneurysms and 105 unruptured aneurysms. In multivariate analysis, age (≥ 60 years OR 2.350 [1.008-5.478]), location (middle cerebral artery OR5.431 [1.347-21.889]; posterior circulation arteries OR 3.189 [1.110-9.163]) and aneurysm size (≥ 5 mm OR 2.855 [1.274-6.397], P = 0.011) were associated with intracranial aneurysm rupture in patients with MMD. In the 2-year follow-up time of aSAH patients, 44% (22/50) had favorable outcomes, 14% (7/50) had unfavorable outcomes and 42% (21/50) had death. Hypertension (HR 6.643 [1.620-27.244], P = 0.009) and Hunt-Hess grade (H&H grade IV HR 14.852 [3.151-70.011], P = 0.001; H&H grade V HR 17.697 [3.046-102.842], P = 0.001) were associated with increased mortality. In contrast, both ST (HR 0.168 [0.031-0.921], P = 0.04) and ET (HR 0.289 [0.087-0.957], P = 0.042) achieved good results.

CONCLUSIONS

This study showed that the proportion of MMD in IA patients was approximately 1.5% (181/11686). For patients with cerebral ischemia on admission, revascularization may prevent the rupture of intracranial aneurysms. Age ≥ 60 years, location, and aneurysm size ≥ 5 mm were associated with IA rupture. Further analysis showed that being located in the middle cerebral artery was the most relevant risk factor for rupture. Patients with ruptured IA who underwent ST or ET had better clinical outcomes and survival than those who underwent CT; however, hypertension and poor initial Hunt-Hess grade were independent predictors of death.

Rapidly growing distal choroidal artery aneurysm re-rupture following revascularization for hemorrhagic Moyamoya disease: A case report

Intracranial hemorrhage is the leading cause of neurological deficits and poor prognosis in adult patients with Moyamoya disease (MMD). Intracranial hemorrhage is occasionally accompanied by MMD-associated aneurysm and requires additional treatment. To date, direct or indirect bypass surgery or endovascular treatment, such as coil embolization, has been adopted and has achieved successful outcomes. The rapid growth of MMD-associated aneurysms and rebleeding after direct bypass surgery via superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis has rarely been reported. We report a case of a rapidly growing fragile arterial pseudoaneurysm in a patient with MMD. A 45-year-old female was admitted with a headache and decreased mental status. Radiological evaluation, including distal subtraction angiography, revealed intraventricular hemorrhage with a left posterior choroidal artery pseudoaneurysm. Within 4 days after revascularization surgery via STA-MCA direct bypass, the size of the pseudoaneurysm rapidly increased and rebleeding occurred, requiring coil embolization. After endovascular therapy and a second STA-MCA bypass surgery, the patient recovered well and was discharged 8 days later. Follow-up radiological imaging revealed an obliterated pseudoaneurysm without rebleeding or complications. In this case, the rapid growth of an MMD-associated pseudoaneurysm was observed after revascularization surgery because of temporary hemodynamic instability. This report raises questions regarding the causes and management of unstable postbypass hemodynamics.

Adult Moyamoya Disease and Syndrome: Current Perspectives and Future Directions: A Scientific Statement From the American Heart Association/American Stroke Association

Adult moyamoya disease and syndrome are rare disorders with significant morbidity and mortality. A writing group of experts was selected to conduct a literature search, summarize the current knowledge on the topic, and provide a road map for future investigation. The document presents an update in the definitions of moyamoya disease and syndrome, modern methods for diagnosis, and updated information on pathophysiology, epidemiology, and both medical and surgical treatment. Despite recent advancements, there are still many unresolved questions about moyamoya disease and syndrome, including lack of unified diagnostic criteria, reliable biomarkers, better understanding of the underlying pathophysiology, and stronger evidence for treatment guidelines. To advance progress in this area, it is crucial to acknowledge the limitations and weaknesses of current studies and explore new approaches, which are outlined in this scientific statement for future research strategies.

Successful shrinkage of anterior communicating artery aneurysm after ACA–ACA bypass with interposed occipital artery graft in pediatric moyamoya disease: illustrative case

BACKGROUND

Selecting therapeutic options for moyamoya disease (MMD)-associated anterior communicating artery (ACoA) aneurysm, a rare pathology in children, is challenging because its natural course remains unclear.

OBSERVATIONS

A 4-year-old boy exhibiting transient ischemic attacks was diagnosed with unilateral MMD accompanied by an unruptured ACoA aneurysm. Although superficial temporal artery to middle cerebral artery anastomosis eliminated his symptoms, the aneurysm continued to grow after surgery. Since a previous craniotomy and narrow endovascular access at the ACoA precluded both aneurysmal clipping and coil embolization, the patient underwent a surgical anastomosis incorporating an occipital artery graft between the bilateral cortical anterior cerebral arteries (ACAs). This was intended to augment blood flow in the ipsilateral ACA territory and to reduce the hemodynamic burden on the ACoA complex. The postoperative course was uneventful, and radiological images obtained 12 months after surgery revealed good patency of the bypass and marked shrinkage of the aneurysm in spite of the intact contralateral internal carotid artery.

LESSONS

Various clinical scenarios should be assessed carefully with regard to this pathology. Bypass surgery aimed at reducing flow to the aneurysm might be an alternative therapeutic option when neither coiling nor clipping is feasible.

Treatment of ruptured aneurysms of the choroidal collateral system in moyamoya disease: a systematic review and data analysis

OBJECTIVE

Moyamoya disease (MMD) is a chronic, progressive steno-occlusive condition of the distal internal carotid arteries of unknown etiology. Collateral arterial networks typically develop in MMD, bypassing the steno-occlusion. Aneurysms arising on the collateral networks are a known source of hemorrhage. The choroidal collateral system is the most common location for collateral pathway aneurysms in MMD and associated hemorrhage. The authors performed data collection and analysis to further elucidate the best treatment approaches for ruptured aneurysms of the choroidal collateral system in MMD, which as yet remain unclear.

METHODS

A comprehensive data collection and analysis of case reports and case series with ruptured choroidal collateral artery aneurysms (CCAAs) was performed. PRISMA guidelines for systematic reviews were followed and the Medline, Embase, and Scopus databases were searched for relevant studies. A database was created including patients with ruptured CCAA in MMD. Original data from case series were included whenever possible. A previously unreported case of a ruptured choroidal artery aneurysm in MMD treated by the authors was also included.

RESULTS

The database comprised 72 patients with ruptured CCAA in MMD. The most common clinical symptoms were headache, nausea, and vomiting (39%). Initially, a conservative treatment approach was chosen in 29% of cases but led to rehemorrhage in 40% of cases; 63% of these rehemorrhages occurred during the first 35 days. Endovascular treatment seemed a safe option for aneurysm exclusion, mainly through parent vessel sacrifice, but had a treatment failure rate of 21%, due to inadequate access. Aneurysm treatment with revascularization as the initial treatment strategy led to aneurysm regression in 82% with no reported rehemorrhage. Aneurysm exclusion through open surgery was effective but was associated with a relatively high complication rate (25%). Outcome after rupture of CCAA was poor, with 41% of patients deceased or permanently disabled. Overall, patient outcomes were better in the endovascular and revascularization treatment group than in the conservative treatment group.

CONCLUSIONS

Rupture of CCAA in MMD is associated with high morbidity and rerupture rate requiring urgent treatment.

Cerebral Aneurysms with Internal Carotid Artery Agenesis: A Unique Case Similar to Moyamoya Disease and Literature Review

Internal carotid artery (ICA) agenesis/aplasia is occasionally accompanied with cerebral aneurysms caused by hemodynamic stress. If the aneurysms are located around the circle of Willis, they are managed with clipping or coil embolization. Herein, we report a case of ICA agenesis with perforating artery aneurysms treated successfully with revascularization. Moreover, a literature review of ICA agenesis with cerebral aneurysms was performed to compare with the current case. We conducted a literature review using data from PubMed. A secondary search was also performed by reviewing the references of each article previously searched. In our case, the aneurysms shrank and disappeared after direct and indirect bypass surgeries, and indirect bypass developed as in moyamoya disease (MMD). The epidemiological and clinical features of aneurysms accompanied with ICA agenesis were identified via a literature review. Aneurysms with ICA agenesis categorized as type F based on the Lie classification system, or referred to as rete mirabile, are occasionally located in an untreatable site; hence, they cannot be treated with clipping or coil embolization. Moreover, results showed that previous studies did not use revascularization for the treatment of aneurysm. In conclusion, if an aneurysm with ICA agenesis is difficult to approach directly or via an endovascular procedure, revascularization can be a treatment option.

Clinical features and prognostic analysis of moyamoya disease associated with intracranial aneurysms

OBJECTIVES

To explore clinical features and compare of the difference between conservative treatment and surgical treatmentin prognosis of intracranial aneurysms associated with moyamoya disease (MMD).

METHODS

104 patients with MMD a ssociated with intracranial aneurysms diagnosed by digital subtraction angiography (DSA) or computed tomography angiography (CTA) were retrospectively analyzed.

RESULTS

All patients of MMD with intracranial aneurysms had 129 aneurysms distributed at different sites. The distribution of the aneurysms was as follows: 28(21.71%) anterior communicating artery aneurysms, 21(16.28%) basilar artery aneurysms, 19(14.73%) middle cerebral artery aneurysms, 17(13.18%) posterior cerebral artery aneurysms, 12(9.30%)internal carotid artery aneurysms, 11(8.53%) posterior communicating artery aneurysms, 10(7.75%) anterior cerebral artery aneurysms, 5(3.88%) anterior choroidal artery aneurysms, 2(1.55%) moyamoya vessel aneurysms, and 4(3.1%) other location aneurysms. 82 cases (78.85%) had one aneurysm, and 21 cases (20.19%) had 2 or more aneurysms. 64 cases were treated surgically, and 40 cases were treated conservatively. 57 of 81 cases (70.37%) had a good outcome, 2 cases (2.47%) were in paralyzed, and 22 cases were died. The mortality rate was (27.16%). Death occurred in 16 (47.06%) of 34 patients with conservative treatment, and 6(12.77%) of 47 patients with surgical treatment. 7 cases (8.64%) had twice cerebral hemorrhage, and one case (1.23%) had third cerebral hemorrhage in the follow-up period. There were 5 deaths, two good outcomes, and one coma among 8 cases experienced re-hemorrhage.

CONCLUSION

Compared with conservative treatment, positive surgical treatment showed clinical significance for preventing cerebral hemorrhage and reducing mortality of MMD with intracranial aneurysms.

ABBREVIATIONS

MMD: moyamoya disease; DSA: digital subtraction angiography; CTA: computed tomography angiography.

Treatment strategies of ruptured intracranial aneurysms associated with moyamoya disease

OBJECTIVE

The purpose of this study was to present our experience in the management of ruptured intracranial aneurysms associated with moyamoya disease (MMD), and to discuss their treatment strategies and the timing of revascularization surgery.

PATIENTS AND METHODS

Thirteen patients who had ruptured intracranial aneurysms associated with MMD were enrolled in this study. Different treatment strategies were adopted based on the location of the aneurysms. Their clinical and radiologic features, treatment selection and outcomes were retrospectively reviewed.

RESULTS

Among the five patients with major artery aneurysms in anterior circulation, three were embolized and two clipped. Among the five patients with major artery aneurysms in posterior circulation, three were treated by endovascular coiling. Among the three peripheral aneurysms, one was treated by endovascular embolization, one by aneurysmectomy, and the other one by revascularization alone. For the patients whose aneurysms were treated by endovascular embolization or surgery, a staged revascularization was performed on day 28 to day 87 after the first operation. For the two patients with aneurysms untreated directly, the timing of revascularization was 20 days and 54 days after hemorrhage, respectively. During the follow-up recurrent intracranial hemorrhage occurred in a patient, but not caused by the previous aneurysm. No other patients suffered recurrent intracranial hemorrhage or ischemic stroke. Complete occlusion was achieved in all the 11 aneurysms that had been clipped or embolized. Of the remaining three aneurysms that had not been directly treated, one disappeared spontaneously, whereas the other two remained stable. The direct and indirect bypasses were confirmed patent in the 11 patients who had undergone revascularization.

CONCLUSION

Our current treatment strategies and timing of revascularization may provide a benefit for the patients with MMD accompanied by ruptured intracranial aneurysms.

Location-based treatment of intracranial aneurysms in moyamoya disease: a systematic review and descriptive analysis

We conducted a systematic review of the literature to evaluate the efficacy of various treatment modalities for intracranial aneurysms (IA) in patients with moyamoya disease (MMD) based on anatomical location of IA. A comprehensive review of studies documenting single cases or series of MMD patients with concomitant IA was conducted. Aneurysms were classified into two primary anatomical categories: those of the Circle of Willis (CoW) and those of peripheral "moyamoya" collateral vessels. Conservative, endovascular, and open surgical treatment modalities and their outcomes between each anatomical subgroup were descriptively compared. A total of 124 studies consisting of 275 patients with 313 IA were included. Of all IA, 59.6% were located on CoW vessels, 33.7% on peripheral vessels, and 6.7% in "other" locations. Of all CoW IA, 87.2% treated with endovascular techniques had no or minimal deficit at follow-up as compared with 56.7% of those treated with open surgery. Ninety-five percent of patients with peripheral aneurysms treated with endovascular therapy had no or minimal deficit, in contrast to open surgery (69.6%). Of peripheral IA treated conservatively with or without revascularization, 65.7% had spontaneous resolution as compared with 12.0% IA of the CoW. Our results support the use of endovascular techniques for direct treatment of both CoW and peripheral IA. Aneurysms of peripheral vessels respond well to indirect treatment through surgical revascularization as opposed to CoW aneurysms. The quality of evidence is limited due to heterogeneity of included studies and IA management in MMD patients should be considered in a case-specific manne.

Intracranial Aneurysms in White Patients with Moyamoya Disease: A U.S. Single-Center Case Series and Review

BACKGROUND

Intracranial aneurysms (IA) are associated with moyamoya disease (MMD). There are no clinically tested treatment guidelines. Reporting of cases is vital to better understand the underlying pathophysiology and potential ethnic predispositions and improve patient selection for intervention.

METHODS

Records of all patients diagnosed with MMD with concomitant IA who presented to our institution were retrospectively reviewed. Data related to demographic, clinical, MMD characteristics, aneurysm characteristics, surgical intervention, and follow-up were collected from the records of each patient. Aneurysm location was categorized into circle of Willis (CoW) aneurysms (originating from the CoW or its major branches) and peripheral aneurysms (arising from choroidal or lenticulostriate arteries).

RESULTS

Ten patients were found to have a total of 14 IA. All patients were white. Ten aneurysms (71%) were classified as CoW aneurysms and 4 (29%) were classified as peripheral. Seven of 10 CoW aneurysms (70%) were located in the anterior circulation, whereas 3 (30%) were located in the posterior circulation. Aneurysms of anterior and posterior circulations were most commonly treated with coil embolization, whereas peripheral artery aneurysms were most commonly treated with either cerebral revascularization alone or aneurysm excision.

CONCLUSIONS

Revascularization surgery seems to be an effective method of indirectly treating IA in patients with MMD. Previous literature in addition to our series shows that endovascular embolization is safe and efficacious in treating IA of most locations in patients with MMD. The use of open microsurgery for direct aneurysm treatment in this population poses many challenges.

The prospects and pitfalls in the endovascular treatment of moyamoya disease-associated intracranial aneurysms

Moyamoya disease (MMD) is characterized by progressive stenosis or occlusion of the distal internal carotid artery and simultaneous formation of collateral vasculature. The fragile alteration and increased hemodynamic stress in the intra- and extracranial vasculature would conjointly result in the formation of intracranial aneurysms in MMD patients. According to our classification, the MMD-associated aneurysms are divided into the major artery aneurysms (MAAs) and non-MAAs. The non-MAAs are further subdivided into the distal choroidal artery aneurysms, moyamoya vessel aneurysms, transdural collateral aneurysms, and anastomosis aneurysms. Currently, endovascular treatment (EVT) has become the main stream for the MMD-associated aneurysms. There is no difference to EVT for the MMD-associated MAAs of the non-stenosed major arteries with that in the non-MMD patients. While it is a big challenge to perform EVT for MMD-associated aneurysms in the stenosed arteries. Generally speaking, the parent arteries of the non-MAAs are slim, and super-selective catheterization is technically difficult. Most of the times, parent artery occlusion with liquid embolic agents or coils can only be performed. The vasculature in MMD patients is fragile; perioperative management and meticulous intraoperative manipulation are also very important to avoid complications during EVT. In spites of the complications, the EVT can bring good outcome in selected cases of MMD-associated aneurysms.

Spontaneous recession of a posterior cerebral artery aneurysm concurrent with carotid rete mirabile and moyamoya-pattern collateral vessels: a case report

Background

Carotid rete mirabile (RM) is a meshwork of multiple, freely intercommunicating arterioles that reconstitute the absent or hypoplastic segments of the internal carotid artery (ICA). Carotid RM has been reported to be associated with cerebrovascular diseases. However, it is rarely associated with moyamoya-pattern collateral vessels in the posterior cerebral artery (PCA) region and aneurysm.

Case presentation

A 39-year-old woman was admitted complaining of sudden-onset headache, nausea, and vomiting. Further investigation revealed subarachnoid hemorrhage (SAH), carotid RM, a moyamoya collateral pattern in the PCA region, and a pseudoaneurysm in the moyamoya-like vessels. The patient was treated conservatively, recovered well and was discharged 1 week later. Follow-up angiography showed that the aneurysm had disappeared.

Conclusions

As shown by the present case, we believe that carotid RM could occur in combination with moyamoya-pattern collateral vessels in the PCA region; aneurysms can occur in the moyamoya-like vascular network. Congenital etiology may be the reason for these combinations. Based on our approach in this case, aneurysm located in moyamoya-like vessels can disappear spontaneously after conservative treatment.

Peek through the smoke: a report of moyamoya disease in a 32-year-old female patient presenting with ischaemic stroke

Moyamoya disease is a vasculopathy causing chronic progressive stenosis and occlusion of the large arteries of the circle of Willis that could lead to brain ischaemia. The condition may also present with haemorrhagic strokes. This is a case report of moyamoya disease in a 32-year-old woman presenting with ischaemic stroke. The report describes her inpatient stay and investigations and findings.The report reviews the main aspects of moyamoya disease definition, epidemiology, clinical features, diagnosis, classification and treatment. This case is interesting because her first presentation occurred after 3 months of her second delivery. Whether the different physiological stresses of pregnancy, child birth and puerperium have had some effect in accelerating the pathogenesis of her moyamoya disease remains unknown. ¹.

Embolization with NBCA for Ruptured Aneurysm Located in the Moyamoya-like Collateral Network Associated with Isolated Middle Cerebral Artery Occlusion

Collateral vessel formation in moyamoya disease is a well-described phenomenon. However, the occurrence of unusual anastomosis pattern (moyamoya-like) associated with isolated middle cerebral artery (MCA) stenosis or occlusion has been reported very rarely and is not well known the relationship with aneurysm. We report a case of ruptured aneurysm treated with N-butyl cyanoacrylate (NBCA) located in moyamoya like collateral network with isolated MCA occlusion.

Analysis of the clinical characteristics of hemorrhagic moyamoya disease in the Jilin province of northeastern China: A single-center study of 212 cases

The present study aimed to investigate the clinical characteristics of hemorrhagic moyamoya disease (MMD) in Jilin province in northeast China. A total of 212 cases of hemorrhagic MMD were consecutively enrolled from the First Hospital of Jilin University in Changchun, China between January 2011 and January 2015. The patients' general clinical data, including age and gender characteristics, history of previous illnesses, hemorrhage type and onset symptoms, Hunt-Hess classification at admission, imaging characteristics, association with aneurysms, treatments and prognosis, were recorded and analyzed using SPSS 19.0. The results demonstrated that i) patients with hemorrhagic MMD in Jilin province were 47.7±11.5 years of age; ii) hemorrhagic MMD was primarily characterized by subarachnoid hemorrhage; iii) a total of 51.9% of the hemorrhagic MMD cases involved a unilateral artery; iv) a total of 24.1% of the hemorrhagic MMD cases were accompanied by anterior choroid artery and/or posterior communicating artery expansion; and v) following conservative or surgical treatment, patients with a prognostic Glasgow Outcome Scale score of 5 accounted for 65.6% of the study population. Therefore, the present study identified characteristics of MMD in Jilin province in northeast China. These results may improve understanding of the epidemiology of MMD in China, which at present remains not well established. Although the results are representative only of Jilin province in China, the study demonstrated high consistency with other studies, and thus may indirectly contribute to general understanding of hemorrhagic MMD etiology.

Keyhole Supraorbital Craniotomy for Aneurysm Clipping in the Setting of Bypass for Moyamoya Disease

BACKGROUND

In 3%-15% of patients with moyamoya disease, aneurysms occur throughout the circle of Willis. In moyamoya patients treated with a superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass, treatment of a new or an enlarging aneurysm can be complicated by the presence of the bypass and by limitations on the use of standard frontotemporal craniotomies to gain access to the aneurysm. Furthermore, endovascular access can be limited by the presence of fragile moyamoya vessels and precluded by atresia of large vessels.

CASE DESCRIPTION

A 45-year-old female patient with a history of moyamoya disease and previous left STA-MCA bypass presented with an enlarging left superior cerebellar artery aneurysm. We used a keyhole supraorbital craniotomy as a minimally invasive route to treat this aneurysm of the circle of Willis, with minimal interruption to the existing bypass or collateral circulation.

CONCLUSIONS

In patients with moyamoya disease who have existing STA-MCA bypass and de novo or expanding aneurysms, treatment is fraught with challenges. We advocate the use of a minimally invasive keyhole supraorbital craniotomy with an eyebrow incision for aneurysms associated with moyamoya disease occurring on the proximal anterior cerebral and middle cerebral arteries, the anterior communicating artery, the basilar apex, the posterior communicating artery, the proximal superior cerebellar artery, and the posterior cerebral artery.

Moyamoya disease associated with arteriovenous malformation and anterior communicating artery aneurysm: A case report and literature review

Moyamoya disease (MMD) can be associated with an aneurysm or arteriovenous malformation (AVM). However, no case of MMD simultaneously associated with both intracranial aneurysm and AVM has been previously reported. The present study reports the case of a patient with MMD simultaneously associated with both aneurysm and AVM. The patient was a 46-year-old woman presenting with a subarachnoid hemorrhage whose imaging diagnosis of MMD was associated with an aneurysm and AVM. The aneurysm was located in the anterior communicating artery, which was similar to a berry aneurysm caused by hemodynamics. The AVM was located in the posterior circulation. Beyond the presentation of the posterior cerebral artery, the appearance of an artery supplying blood from the middle cerebral artery supported the view that the AVM was congenital and unruptured. Conservative treatment was provided and examination of the patient at follow-up showed good recovery. In addition to the case report, the present study also reviewed the relevant literature in order to compile information on MMD associated with both an aneurysm and AVM.

Onyx embolization of a ruptured aneurysm in a patient with moyamoya disease

We report a woman who presented with an intraparenchymal hemorrhage. Her cerebral angiogram showed a middle cerebral artery (MCA) M1 occlusion with multiple collaterals supplying the distal MCA territory, compatible with moyamoya disease. Also, an associated 8 mm dysplastic distal aneurysm fed by a left-sided P2 perforator was seen, collateral from the posterior cerebral artery. The aneurysm was successfully occluded with Onyx (ev3 Endovascular, Plymouth, MN, USA) embolization. The woman had an uneventful postoperative course. Aneurysm formation in patients with moyamoya disease represents a major hemorrhagic risk. Several treatment strategies exist including endovascular and surgical approaches. Patients with moyamoya disease who present with aneurysmal intracerebral hemorrhage should be treated to prevent rebleeding. Onyx embolization can be an effective treatment of aneurysms that are associated with moyamoya disease and would otherwise be difficult to treat surgically.

Treatment strategies for aneurysms associated with moyamoya disease

The treatment of aneurysms associated with moyamoya disease (MMD) is difficult for neurosurgeons, and little is known of strategy options. This report constitutes a comprehensive review of the literature. We summarize the known treatments and their clinical outcomes according to the site of the aneurysm: in major arteries, peripheral arteries, moyamoya vessels, meningeal arteries, or at the site of anastomosis. The literature review indicates that the treatment of MMD-associated aneurysms varies according to the site of the aneurysm and its hemodynamic characteristics. In particular, the treatment for basilar tip aneurysms remains challenging, since both endovascular embolization and direct clipping are difficult. The potential risk for ischemia should be considered in selecting endovascular or surgical approaches. Revascularization surgery, which is important for the treatment of MMD, also determines the clinical treatment outcome of aneurysms associated with MMD.

Endovascular treatment of a ruptured flow aneurysm of the heubner artery as part of a moyamoya collateral network in a young patient with an occluded middle cerebral artery

A young woman with an occluded middle cerebral artery presented with a ruptured flow aneurysm distal on a Heubner artery as part of a moyamoya collateral network. Leptomeningeal collateral supply was tested by occlusion of the A1 origin of the Heubner artery. This test occlusion demonstrated ample collateral leptomeningeal supply over the hemispheres to the M2. Subsequently, the Heubner artery harbouring the aneurysm could be safely proximally occluded with coils.

Exacerbation of major artery aneurysms after revascularization in patients with moyamoya disease: two case reports

The natural history of aneurysms of the major arteries after revascularization in moyamoya disease has yet to be documented. At our institute, we treated two patients with moyamoya disease-associated aneurysms involving major arteries of the posterior cerebral circulation. The aneurysms became enlarged at an early stage after revascularization, necessitating coil embolization. Although cerebral blood flow was improved in the anterior circulation, revascularization for these patients did not decrease hemodynamic stress in the posterior circulation and was not able to attenuate aneurysmal growth. Therefore, patients with moyamoya disease-associated aneurysms of the major arteries should be carefully monitored after revascularization.

Selective and superselective angiography of pediatric moyamoya disease angioarchitecture: the anterior circulation

The angioarchitecture of the so-called moyamoya vessels in children has not been explicitly analyzed. We aimed to investigate the precise anatomy of the vascular anastomotic networks in patients with childhood moyamoya disease. Six children diagnosed with moyamoya disease for the first time underwent an angiographic investigation with selective and superselective injections. We recorded the arterial branches feeding the moyamoya anastomotic networks, their connections and the recipient vessels. Depending on the level of the steno-occlusive lesion, the feeding vessels included the medial striate arteries, the perforators of the choroidal segment of the carotid, the uncal artery, the medial and lateral branches of the intraventricular segment of the anterior choroidal artery, perforators of the communicating segment, the superior hypophyseal arteries, the prechiasmal branches of the ophthalmic artery, the ethmoidal arteries and the dural branches of the cavernous carotid. Through connections, which are described, the recipient vessels were the lateral striate arteries and the middle cerebral, the medial striate arteries and the anterior cerebral, medullary arteries around the ventricular system, anterior temporal branches of the middle cerebral, orbitofrontal and frontopolar branches of the anterior cerebral, as well as other cortical branches of the anterior and middle cerebral territories. The use of high quality selective and superselective angiography enabled us to clearly demonstrate for the first time aspects of the microangiographic anatomy of the moyamoya anastomotic network previously only vaguely or incompletely described.

Selective and superselective angiography of pediatric moyamoya disease angioarchitecture in the posterior circulation

The anastomotic network of the posterior circulation in children with moyamoya disease has not been analyzed. We aimed to investigate the angiographic anatomy of this unique vascular network in patients with childhood moyamoya disease. Selective and superselective injections of the posterior circulation were performed in six children with newly diagnosed moyamoya disease. The arterial branches feeding the moyamoya anastomotic network, their connections and the recipient vessels were demonstrated. Depending on the level of the steno-occlusive lesion, the feeding vessels were the thalamoperforators, the posterior choroidals, the splenic artery, parietoccipital artery, other cortical posterior cerebral artery (PCA) branches, the dural branch of the PCA, the premamillary artery and other posterior communicating artery perforators. Through connections, which are described, the recipient vessels were the striate and medullary arteries, other thalamic arteries with or without medullary extensions, the pericallosal artery, medial parietoccipital cortical branches of the PCA and the anterior choroidal artery. High quality selective and superselective angiography helped in demonstrating the angiographic anatomy of the moyamoya posterior anastomotic network previously either vaguely or incompletely described, as well as connections within the posterior circulation but also its relevance as a collateral to the anterior circulation.

Resolution of bilateral moyamoya associated collateral vessel aneurysms: Rationale for endovascular versus surgical intervention

BACKGROUND

Management of aneurysms associated with deep collateral vessels in moyamoya disease is challenging both from an endovascular and a surgical standpoint. Difficulties with access or localization, and compromise of the collateral circulation with subsequent ischemia are the primary concerns, making direct obliteration potentially unfeasible or risky. Alternatively, superficial temporal artery-middle cerebral artery bypass is another potential strategy for resolution of these aneurysms.

CASE DESCRIPTION

Presented are the findings and management for a patient with moyamoya disease and bilateral deep collateral vessel aneurysms, successfully treated with endovascular obliteration following a right-sided hemorrhage and subsequently with bypass for an unruptured but growing contralateral aneurysm.

CONCLUSIONS

A rationale and approach to management is outlined, as derived from review of the current literature and the illustrative case with bilateral collateral vessel aneurysms.

Middle cerebral artery occlusion with moyamoya-like vessels and aneurysms. A report of two cases

We describe two cases of aneurysmal rupture in moyamoya-like vessels in middle cerebral artery occlusion. This phenomenon was previously described in severe steno-occlusive disease and accounts for the hemorrhagic presentation. To our knowledge, these are the second and third clinical cases published in modern neuroradiological literature.

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.