Changes of cerebral cortical structure and cognitive dysfunction in “healthy hemisphere” after stroke: a study about cortical complexity and sulcus patterns in bilateral ischemic adult moyamoya disease

Background Moyamoya disease (MMD) is an uncommon cerebrovascular disease which leads to progressive stenosis and occlusion of the bilateral internal carotid artery and main intracerebral arteries. Concerns are always on how the hemisphere with infarction affects cognitive function, while little attention is paid to the role that the non-infarcted hemisphere plays. Therefore, we aimed to detect cortical indexes, especially cortical complexity in the left or right hemisphere separately in patients with MMD after stroke. Methods 28 patients with MMD (14 males, 14 females) and 14 healthy controls were included in this study. All participants underwent cognitive tests and magnetic resonance imaging (MRI) scan. The preprocessing of three-dimensional T1 weighted images were performed by standard surface-based morphometry. Surface-based morphometry statistical analysis was carried out with a threshold of False Discovery Rate (FDR) P < 0.05 and fractal dimension (FD) was used to provide a quantitative description of cerebral cortical complexity. Results Widespread cognitive dysfunctions were found in MMD patient with stroke. Extensive FD reduction in the left hemisphere with right-sided infarction, mainly in the superior temporal, inferior frontal, and insula, while the post central gyrus, superior parietal, and inferior parietal gyrus also showed a wide range of significant differences (FDR corrected P < 0.05). Meanwhile, FD changes in the right hemisphere with left-sided infarction are restricted to the precuneus and cingulate isthmus (FDR corrected P < 0.05). Conclusions Extensive cognitive impairment was reconfirmed in Moyamoya disease with stroke, while wild and asymmetrical decrease of cortical complexity is observed on both sides. These differences could be relative to unbalanced cognitive dysfunction, and may be the result of a long-term chronic ischemia and compensatory of the contralateral hemisphere to the infarction.

Benefits and risks of antiplatelet medication in hemodynamically stable adult moyamoya disease

Revascularization surgery is considered a standard treatment for preventing additional stroke in symptomatic moyamoya disease (MMD). In hemodynamically stable, and asymptomatic or mildly symptomatic patients, however, the treatment strategy is controversial because of the obscure natural course of them. The authors analyzed the benefits and risks of antiplatelet medication in those patients. Medical data were retrospectively reviewed in 439 hemispheres of 243 patients with stable hemodynamic status. Overall, 121 patients (49.8%) with 222 studied hemispheres (50.6%) took antiplatelet medication. Symptomatic cerebral infarction and hemorrhage occurred in 10 (2.3%) and 30 (6.8%) hemispheres, over a mean follow-up of 62.0 ± 43.4 months (range 6–218 months). The use of antiplatelet agents was statistically insignificant in terms of symptomatic infarction, hemorrhage and improvement of ischemic symptoms. In subgroup analyses within the antiplatelet group according to drug potency and duration of medication, a longer duration of antiplatelet medication significantly improved ischemic symptoms (adjusted OR 1.02; 95% CI 1.01–1.03; p = 0.006). Antiplatelet medication failed to prevent symptomatic cerebral infarction or improve ischemic symptoms. However, antiplatelet therapy did not increase the risk of cerebral hemorrhage.

Surgical Treatment of Adult Moyamoya Disease In Saudi Arabia: A Review Article

Moyamoya disease (MMD) is an isolated chronic, usually bilateral, vasculopathy disease of undetermined etiology. The clinical presentations of MMD include TIA, ischemic stroke, hemorrhagic stroke, seizures, headache, and cognitive impairment. Intra- and extra-cranial revascularization for the prevention of recurrence of bleeding in patients with hemorrhagic MMD is controversial. Surgical revascularization of MMD includes 3 types: Direct revascularization, indirect revascularization and combined revascularization. The surgical goal of cerebral revascularization is to prevent progression of symptomology, alleviate intracranial hemodynamic stress, and reduce the incidence of subsequent ischemic or hemorrhagic stroke. However, surgical treatments pose various complications due to the sudden increase in cerebral blood flow or hemodynamic changes caused by perioperative risk factors and anesthesia, such as HS, cerebral hemorrhage and cerebral infarction, bypass occlusion caused by distal vascular resistance, bypass occlusion caused by compression of the temporalis, and anastomotic aneurysm.

Faded Critical Dynamics in Adult Moyamoya Disease Revealed by EEG and fMRI

Criticality is considered a dynamic signature of healthy brain activity that can be measured on the short-term timescale with neural avalanches and long-term timescale with long-range temporal correlation (LRTC). It is unclear how the brain dynamics change in adult moyamoya disease (MMD). We used BOLD-fMRI for LRTC analysis from 16 hemorrhagic ( H MMD ) and 34 ischemic ( I MMD ) patients and 25 healthy controls. Afterwards, they were examined by EEG recordings in the eyes-closed (EC), eyes-open (EO), and working memory (WM) states. The EEG data of 11 H MMD and 13 I MMD patients and 21 healthy controls were in good quality for analysis. Regarding the 4 metrics of neural avalanches (e.g., size ( α ), duration ( β ), κ value, and branching parameter ( σ )), both MMD subtypes exhibited subcritical states in the EC state. When switching to the WM state, H MMD remained inactive, while I MMD surpassed controls and became supercritical ( p < 0.05 ). Regarding LRTC, the amplitude envelope in the EC state was more analogous to random noise in the MMD patients than in controls. During state transitions, LRTC decreased sharply in the controls but remained chaotic in the MMD individuals ( p < 0.05 ). The spatial LRTC reduction distribution based on both EEG and fMRI in the EC state implied that, compared with controls, the two MMD subtypes might exhibit mutually independent but partially overlapping patterns. The regions showing decreased LRTC in both EEG and fMRI were the left supplemental motor area of H MMD and right pre-/postcentral gyrus and right inferior temporal gyrus of I MMD . This study not only sheds light on the decayed critical dynamics of MMD in both the resting and task states for the first time but also proposes several EEG and fMRI features to identify its two subtypes.

Abstract MP45: Racial Differences in Adult Moyamoya Disease: Clinical Presentation, Angiographic Characteristics, and Outcomes After Revascularization

Introduction: Racial differences in the clinical presentation, angiographic characteristics, and treatment outcomes of adult moyamoya disease (AMMD) are not well-characterized. Methods: Consecutive patients with AMMD prospectively treated at our institution from 2015-2018 were reviewed. Results: 261 patients with AMMD were enrolled (91 Asian/Pacific Islander, 128 Caucasian, 21 Hispanic, 21 Black). Asian patients were older at first clinic visit (43.6±10.8 vs. white 38.0±10.8, Hispanic 41.0±10.3, black 39.1±9.4; p=0.003). There were no differences in rates of hypertension (p=0.23) or smoking (p=0.36), but Hispanic patients had higher rates of diabetes (38% vs. Asian 16%, Caucasian 11.7%, Black 28.5%; p=0.05). All 7 patients with known familial MMD were Asian (p=0.002). There were no differences between races in terms of ischemic or hemorrhagic presentation; however, Asian patients were less likely to present with sentinel events such as headache (50.5% vs. Caucasian 71%, Hispanic 71.4%, Black 52.4%; p=0.03). On pre-operative angiography, Asians were more likely to have anterior choroidal or posterior communicating artery moyamoya collaterals (44% vs. Caucasian 30%, Hispanic 17%, Black 28.6%; p=0.004) and more extensive external carotid artery supply (4.9±10.6% vs. Caucasian 2.2±6.3%, Hispanic 1.3±4.5%, Black 1.1±3.0%; p=0.05). There were no differences in rates of peri-operative symptomatic infarct (p=0.94) or hemorrhage (p=1.0). After revascularization, moyamoya collaterals were more likely to regress/improve in Asians (59% vs. Caucasian 39.5%, Hispanic 28.6%, Black 33%; p=0.005), remain stable in Caucasians (58.6% vs. Asian 36%, Hispanic 52.4%, Black 56%; p=0.03), and increase/worsen in Hispanics (19% vs. Asian 5%, Caucasian 1.9%, Black 11%; p=0.01). At last follow-up with a mean of 1.91±1.5 years, there were no differences in functional outcomes between races (p=0.94). Conclusions: AMMD patients of Asian descent may present later in the disease course, potentially due to experiencing fewer milder symptoms such as headache that may serve as early warning signs. The effect of revascularization on regression of moyamoya collaterals may differ based on race. The clinical impact of these differences requires further investigation.

Intralateral and Perilateral Ventricular Arteries on Original Axial Magnetic Resonance Angiography in Adult Moyamoya Disease

<b><i>Background:</i></b> Patients with moyamoya disease often develop cerebral infarction and hemorrhage, but the ischemic and hemorrhagic subtypes are difficult to diagnose prior to disease onset. We aimed to differentiate the ischemic and hemorrhagic subtypes of moyamoya disease by analyzing the intralateral and perilateral ventricular arteries on the original axial magnetic resonance angiography (MRA) images. <b><i>Methods:</i></b> We retrospectively analyzed the intralateral and perilateral ventricular arteries on the original axial time-of-flight (TOF)-MRA images of 18 patients with hemorrhagic moyamoya disease, 25 patients with ischemic moyamoya disease, and 22 control patients with unruptured aneurysms. <b><i>Results:</i></b> There were significantly more intralateral and perilateral ventricular arteries on the original axial MRA images in the patients with hemorrhagic moyamoya disease (6.3 ± 2.7) than in those with ischemic moyamoya disease (0.8 ± 0.9) and those with unruptured aneurysms (0.4 ± 0.8). <b><i>Conclusion:</i></b> The intralateral and perilateral ventricular arteries on the original axial TOF-MRA images might suggest the hemorrhagic type of moyamoya disease prior to onset.