Vessel Wall and Lumen Features in North American Moyamoya Patients

Vessel wall imaging in the diagnosis of antiphospholipid syndrome presenting as Moyamoya syndrome-A case report

Objectives: We describe a case of anti-phospholipid syndrome (APLS) vasculopathy presenting with Moyamoya syndrome (MMS) and show the associated intracranial vessel wall MRI (VWI) findings. Methods: A 37-year-old-woman presented with acute onset dizziness and left-sided weakness. Neurologic exam revealed a left facial droop and left hemiparesis. She underwent a comprehensive laboratory work-up for stroke. Neuroimaging included a CT head, CT angiogram, VWI, and digital subtraction angiography. Results: Work-up revealed a triple-positive APLS antibody profile. CT of the head showed an acute right basal ganglia infarction and right frontal subarachnoid hemorrhage. CT angiogram revealed severe stenosis of the right internal carotid artery terminus in a Moyamoya pattern. Intracranial VWI showed long-segment concentric vessel wall thickening and homogeneous vessel wall enhancement and T2-hyperintense wall edema of the stenotic right ICA terminus, M1 middle cerebral artery, and A1 anterior cerebral artery. She was treated with long-term anticoagulation with warfarin and a right superficial temporal artery to middle cerebral artery bypass. Discussion: We present intracranial VWI features of vessel wall pathology in a patient with primary APLS presenting with MMS.

High-resolution magnetic resonance vessel wall imaging provides new insights into Moyamoya disease

Moyamoya disease (MMD) is a rare condition that affects the blood vessels of the central nervous system. This cerebrovascular disease is characterized by progressive narrowing and blockage of the internal carotid, middle cerebral, and anterior cerebral arteries, which results in the formation of a compensatory fragile vascular network. Currently, digital subtraction angiography (DSA) is considered the gold standard in diagnosing MMD. However, this diagnostic technique is invasive and may not be suitable for all patients. Hence, non-invasive imaging methods such as computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are often used. However, these methods may have less reliable diagnostic results. Therefore, High-Resolution Magnetic Resonance Vessel Wall Imaging (HR-VWI) has emerged as the most accurate method for observing and analyzing arterial wall structure. It enhances the resolution of arterial walls and enables quantitative and qualitative analysis of plaque, facilitating the identification of atherosclerotic lesions, vascular entrapment, myofibrillar dysplasia, moyamoya vasculopathy, and other related conditions. Consequently, HR-VWI provides a new and more reliable evaluation criterion for diagnosing vascular lesions in patients with Moyamoya disease.

Isolated anterior cerebral artery occlusion: an atypical form of moyamoya disease

BACKGROUND

The relationship between anterior cerebral artery (ACA) occlusion and moyamoya disease (MMD) has rarely been studied. In this study, we focused on a special type of MMD: isolated ACA-occlusive MMD. We investigated clinical attributes, genotypes and progression risk factors in patients with ACA-occlusive MMD, providing initial insights into the relationship between ACA occlusion and MMD.

METHODS

We retrospectively analysed digital subtraction angiography (DSA) from 2486 patients and diagnosed 139 patients with ACA-occlusive MMD. RNF213 p.R4810K (rs112735431) mutation analysis was performed. Patients were categorised into progression and non-progression groups based on whether they progressed to typical MMD. Differences in clinical characteristics, neuropsychological assessment, radiological findings and genotypes were evaluated. Logistic regression analyses identified risk factors for ACA-occlusive MMD progression.

RESULTS

The median age of patients with ACA-occlusive MMD was 36 years, and the primary symptom was transient ischaemic attack (TIA). 72.3% of ACA-occlusive MMD patients had cognitive decline. Of 116 patients who underwent RNF213 gene mutation analysis, 90 patients (77.6%) carried the RNF213 p.R4810K GG allele and 26 (22.4%) carried the GA allele. Of 102 patients with follow-up DSA data, 40 patients (39.2%) progressed. Kaplan-Meier curve estimates indicated a higher incidence of ischaemic stroke in the progression group during follow-up (p=0.035). Younger age (p=0.041), RNF213 p.R4810K GA genotype (p=0.037) and poor collateral compensation from the middle cerebral artery (MCA) to ACA (p<0.001) were risk factors of ACA-occlusive MMD progression to typical MMD.

CONCLUSIONS

Cognitive decline and TIA might be the main manifestations of ACA-occlusive MMD. Isolated ACA occlusion may be an early signal of MMD. The initial lesion site of MMD is not strictly confined to the terminal portion of the internal carotid artery. Younger patients, patients with RNF213 p.R4810K GA genotype or those with inadequate MCA-to-ACA compensation are more likely to develop typical MMD.

Physiological and pathophysiological mechanisms of the molecular and cellular biology of angiogenesis and inflammation in moyamoya angiopathy and related vascular diseases

Rationale

The etiology and pathophysiological mechanisms of moyamoya angiopathy (MMA) remain largely unknown. MMA is a progressive, occlusive cerebrovascular disorder characterized by recurrent ischemic and hemorrhagic strokes; with compensatory formation of an abnormal network of perforating blood vessels that creates a collateral circulation; and by aberrant angiogenesis at the base of the brain. Imbalance of angiogenic and vasculogenic mechanisms has been proposed as a potential cause of MMA. Moyamoya vessels suggest that aberrant angiogenic, arteriogenic, and vasculogenic processes may be involved in the pathophysiology of MMA. Circulating endothelial progenitor cells have been hypothesized to contribute to vascular remodeling in MMA. MMA is associated with increased expression of angiogenic factors and proinflammatory molecules. Systemic inflammation may be related to MMA pathogenesis.

Objective

This literature review describes the molecular mechanisms associated with cerebrovascular dysfunction, aberrant angiogenesis, and inflammation in MMA and related cerebrovascular diseases along with treatment strategies and future research perspectives.

Methods and results

References were identified through a systematic computerized search of the medical literature from January 1, 1983, through July 29, 2022, using the PubMed, EMBASE, BIOSIS Previews, CNKI, ISI web of science, and Medline databases and various combinations of the keywords "moyamoya," "angiogenesis," "anastomotic network," "molecular mechanism," "physiology," "pathophysiology," "pathogenesis," "biomarker," "genetics," "signaling pathway," "blood-brain barrier," "endothelial progenitor cells," "endothelial function," "inflammation," "intracranial hemorrhage," and "stroke." Relevant articles and supplemental basic science articles almost exclusively published in English were included. Review of the reference lists of relevant publications for additional sources resulted in 350 publications which met the study inclusion criteria. Detection of growth factors, chemokines, and cytokines in MMA patients suggests the hypothesis of aberrant angiogenesis being involved in MMA pathogenesis. It remains to be ascertained whether these findings are consequences of MMA or are etiological factors of MMA.

Conclusions

MMA is a heterogeneous disorder, comprising various genotypes and phenotypes, with a complex pathophysiology. Additional research may advance our understanding of the pathophysiology involved in aberrant angiogenesis, arterial stenosis, and the formation of moyamoya collaterals and anastomotic networks. Future research will benefit from researching molecular pathophysiologic mechanisms and the correlation of clinical and basic research results.

Evaluation of vessel-wall contrast-enhancement on high-resolution MRI in European patients with Moyamoya disease

OBJECTIVES

Data regarding MR vessel-wall imaging (VWI) in patients with Moyamoya disease (MMD) is sparse, particularly in non-asian cohorts. We contribute data regarding the frequency of vessel wall contrast-enhancement (VW-CE) and its potential clinical significance in a European patient group.

MATERIALS AND METHODS

Patients with a diagnosis of MMD who were examined by VWI were included in the study. VW-CE of stenoocclusive lesions of the terminal internal carotid artery and/or its proximal branches was rated qualitatively. Changes of VW-CE on available follow-up were recorded. VW-CE was correlated with diffusion-restricted lesions and magnetic resonance angiography (MRA) findings.

RESULTS

Eleven patients (eight female, three male) were included. Twenty-eight stenoocclusive lesions were analyzed, of which 16 showed VW-CE (57.1%). VW-CE was mostly concentric (n=15), rather than eccentric (n=1). In all three patients in whom follow-up VWI was available, changes of VW-CE were documented. Diffusion-restricted lesions were more frequently related to stenoocclusive lesions with VW-CE (n=9) than without VW-CE (n=2), bordering statistical significance. The affected arteries were assessed as stenotic and as occluded in 14 cases each and VW-CE was seen significantly more often in stenotic (n=12) than in occluded arteries (n=4). No correlation was found between the presence of VW-CE and moyamoya stages determined by MRA.

CONCLUSIONS

Our data suggest that concentric VW-CE is a relatively frequent finding in European MMD patients. VW-CE may change over time and occur in certain stages, possibly representing "active stenosing". Larger studies are needed to validate these findings and determine the clinical relevance of VW-CE in MMD.

Characteristic image on cerebral angiography in ruptured blood blister-like aneurysms

OBJECTIVE

To evaluate the static and dynamic features of blood blister-like aneurysms (BBAs) using cerebral angiography to identify characteristic features to improve the diagnosis of these uncommon aneurysms.

METHODS

Digital subtraction angiography (DSA) images were compared between patients with BBAs (n = 12, group A) and patients with unruptured paraclinoid aneurysms ≤ 5 mm in size treated by endovascular procedures (n = 12, group B). DSA images were assessed for irregularities in the diameter of the parent artery and delayed inflow and outflow of contrast medium in the aneurysm. Enlargement of the aneurysm and morphological changes from the first assessment were also evaluated in patients with BBAs.

RESULTS

Compared to the group B, group A had a higher proportion of irregular vessel diameter (p = 0.013) and the delayed contrast medium outflow (p = 0.014). As well, stagnation of contrast medium along the aneurysm wall was a characteristic finding of BBAs, even for small aneurysms.

CONCLUSION

Irregular morphological features of the parent artery and delayed contrast medium outflow as characteristic findings of ruptured BBAs may improve the diagnosis of these uncommon aneurysms, which remains challenging in practice.

Vessel wall imaging features of Moyamoya disease in a North American population: patterns of negative remodelling, contrast enhancement, wall thickening, and stenosis

Background

This study characterized vessel wall imaging (VWI) features of Moyamoya disease (MMD) in a predominantly adult population at a North American center.

Methods

Consecutive patients with VWI were included. Twelve arterial segments were analyzed for wall thickening, degree and pattern of contrast enhancement, and remodeling.

Results

Overall, 286 segments were evaluated in 24 patients (mean age = 36.0 years [range = 1–58]). Of 172 affected segments, 163 (95%) demonstrated negative remodeling. Complete vessel wall obliteration was most frequent in the proximal M1 (17/48, 35%). Affected segments enhanced in 72/172 (42%) (n = 15 for grade II; n = 54 for concentric and n = 18 for eccentric); 20 of 24 (83%) patients had at least one enhancing segment. Both enhancing and non-enhancing segments were present in 19/20 (95%) patients. Vessel wall enhancement was most common in the proximal segments and correlated to the degree of stenosis (p < 0.001), and outer wall diameter (p < 0.001), but not disease duration (p = 0.922) or Suzuki score (p = 0.477). Wall thickening was present in 82/172 (48%) affected segments and was associated with contrast enhancement (p < 0.001), degree of stenosis (p < 0.001), and smaller outer wall diameter (p = 0.004).

Conclusion

This study presents VWI findings in North American patients with MMD. Negative remodeling was the most common finding. Most patients had both enhancing and non-enhancing abnormal segments. Vessel wall enhancement was most common in proximal segments, variable in pattern or degree and was correlated to the degree of stenosis and smaller outer wall diameter.

Presurgical Magnetic Resonance Imaging Indicators of Revascularization Response in Adults With Moyamoya Vasculopathy

BACKGROUND

Moyamoya is a progressive intracranial vasculopathy, primarily affecting distal segments of the internal carotid and middle cerebral arteries. Treatment may comprise angiogenesis-inducing surgical revascularization; however, lack of randomized trials often results in subjective treatment decisions.

HYPOTHESIS

Compensatory presurgical posterior vertebrobasilar artery (VBA) flow-territory reactivity, including greater cerebrovascular reactivity (CVR) and reduced vascular delay time, portends greater neoangiogenic response verified on digital subtraction angiography (DSA) at 1-year follow-up.

STUDY TYPE

Prospective intervention cohort.

SUBJECTS

Thirty-one patients with moyamoya (26 females; age = 45 ± 13 years; 41 revascularized hemispheres).

METHODS

Anatomical MRI, hypercapnic CVR MRI, and DSA acquired presurgically in adult moyamoya participants scheduled for clinically indicated surgical revascularization. One-year postsurgery, DSA was repeated to evaluate collateralization.

FIELD STRENGTH

3 T.

SEQUENCE

Hypercapnic T 2 * -weighted gradient-echo blood-oxygenation-level-dependent, T2 -weighted turbo-spin-echo fluid-attenuated-inversion-recovery, T1 -weighted magnetization-prepared-rapid-gradient-echo, and T2 -weighted diffusion-weighted-imaging.

ASSESSMENT

Presurgical maximum CVR and response times were evaluated in VBA flow-territories. Revascularization success was determined using an ordinal scoring system of neoangiogenic collateralization from postsurgical DSA by two cerebrovascular neurosurgeons (R.V.C. with 8 years of experience; M.R.F. with 9 years of experience) and one neuroradiologist (L.T.D. with 8 years of experience). Stroke risk factors (age, sex, race, vasculopathy, and diabetes) were recorded.

STATISTICAL TESTS

Fisher's exact and Wilcoxon rank-sum tests were applied to compare presurgical variables between cohorts with angiographically confirmed good (>1/3 middle cerebral artery [MCA] territory revascularized) vs. poor (<1/3 MCA territory revascularized) outcomes.

SIGNIFICANCE

two-sided P < 0.05. Normalized odds ratios (ORs) were calculated.

RESULTS

Criteria for good collateralization were met in 25 of the 41 revascularized hemispheres. Presurgical normalized VBA flow-territory CVR was significantly higher in those with good (1.12 ± 0.13 unitless) vs. poor (1.04 ± 0.05 unitless) outcomes. Younger (OR = -0.60 ± 0.67) and White (OR = -1.81 ± 1.40) participants had highest revascularization success (good outcomes: age = 42 ± 14 years, race = 84% White; poor outcomes: age = 49 ± 11 years, race = 44% White).

DATA CONCLUSION

Presurgical MRI-measures of VBA flow-territory CVR are highest in moyamoya participants with better angiographic responses to surgical revascularization.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY STAGE: 4.

7T MRI for Intracranial Vessel Wall Lesions and Its Associated Neurological Disorders: A Systematic Review

Intracranial vessel wall lesions are involved in a variety of neurological diseases. The advanced technique 7T MRI provides greater efficacy in the diagnosis of the pathology changes in the vessel wall and helps to identify potential subtle lesions. The purpose of this literature review was to systematically describe and evaluate the existing literature focusing on the use of 7T MRI in the detection and characterization of intracranial vessel wall lesions and their associated neurological disorders, to highlight the current knowledge gaps, and to formulate a framework to guide future applications and investigations. We systematically reviewed the existing articles up to July 2021, seeking the studies that assessed intracranial vessel wall lesions and their associated neurological disorders using 7T MRI. The literature search provided 12 studies that met the inclusion criteria. The most common intracranial vessel wall lesions were changes related to intracranial atherosclerosis (n = 8) and aneurysms (n = 4), such as intracranial atherosclerosis burden and aneurysm wall enhancement. The associated neurological disorders included aneurysms, ischemic stroke or TIA, small vessel disease, cognitive decline, and extracranial atherosclerosis. No paper studied the use of 7T MRI for investigating vessel wall conditions such as moyamoya disease, small vessel disease, or neurological disorders related to central nervous vasculitis. In conclusion, the novel 7T MRI enables the identification of a wider spectrum of subtle changes and associations. Future research on cerebral vascular diseases other than intracranial atherosclerosis and aneurysms may also benefit from 7T MRI.

Vessel Wall Magnetic Resonance Imaging in Cerebrovascular Diseases

Cerebrovascular diseases are a leading cause of disability and death worldwide. The definition of stroke etiology is mandatory to predict outcome and guide therapeutic decisions. The diagnosis of pathological processes involving intracranial arteries is especially challenging, and the visualization of intracranial arteries’ vessel walls is not possible with routine imaging techniques. Vessel wall magnetic resonance imaging (VW-MRI) uses high-resolution, multiparametric MRI sequences to directly visualize intracranial arteries walls and their pathological alterations, allowing a better characterization of their pathology. VW-MRI demonstrated a wide range of clinical applications in acute cerebrovascular disease. Above all, it can be of great utility in the differential diagnosis of atherosclerotic and non-atherosclerotic intracranial vasculopathies. Additionally, it can be useful in the risk stratification of intracranial atherosclerotic lesions and to assess the risk of rupture of intracranial aneurysms. Recent advances in MRI technology made it more available, but larger studies are still needed to maximize its use in daily clinical practice.

Implementation and Rationale for a Unified Clinical and Imaging Protocol for Evaluation and Treatment of Moyamoya Angiopathy: A Single Institutional Experience

Moyamoya disease (MMD) is a complex and incompletely-understood cerebrovascular pathological entity that requires thorough clinical and imaging evaluation. Moyamoya is rare, thereby making the establishment of an effective, thorough and interdisciplinary patient evaluation protocol challenging, even within specialized referral centers. Nevertheless, implementation of such a protocol is crucial in order to provide the best possible evaluation and treatment for MMD patients. Here, we describe our institution's implementation of, rationale for, and experience with a comprehensive multidisciplinary collaboration and evaluation strategy for adult patients with moyamoya. This evaluation course consists of, first of all, a thorough clinical and laboratory evaluation with a vascular neurologist. This is followed by a comprehensive imaging assessment which evaluates angiographic and parenchymal features, in addition to cerebrovascular functionality. Finally, appropriate referrals are made to consulting services as indicated, which includes vascular neurosurgery. These steps are described in detail herein.