Cerebral circulation in moyamoya disease: a clinical study using transcranial Doppler sonography

Macrohistory of Moyamoya Disease Analyzed Using Artificial Intelligence

INTRODUCTION

Moyamoya disease is characterized by progressive stenotic changes in the terminal segment of the internal carotid artery and the development of abnormal vascular networks called moyamoya vessels. The objective of this review was to provide a holistic view of the epidemiology, etiology, clinical findings, treatment, and pathogenesis of moyamoya disease. A literature search was performed in PubMed using the term "moyamoya disease," for articles published until 2021.

RESULTS

Artificial intelligence (AI) clustering was used to classify the articles into 5 clusters: (1) pathophysiology (23.5%); (2) clinical background (37.3%); (3) imaging (13.2%); (4) treatment (17.3%); and (5) genetics (8.7%). Many articles in the "clinical background" cluster were published from the 1970s. However, in the "treatment" and "genetics" clusters, the articles were published from the 2010s through 2021. In 2011, it was confirmed that a gene called Ringin protein 213 (RNF213) is a susceptibility gene for moyamoya disease. Since then, tremendous progress in genomic, transcriptomic, and epigenetic profiling (e.g., methylation profiling) has resulted in new concepts for classifying moyamoya disease. Our literature survey revealed that the pathogenesis involves aberrations of multiple signaling pathways through genetic mutations and altered gene expression.

CONCLUSION

We analyzed the content vectors in abstracts using AI, and reviewed the pathophysiology, clinical background, radiological features, treatments, and genetic peculiarity of moyamoya disease.

Childhood moyamoya disease and moyamoya syndrome: a pictorial review

Moyamoya disease is an uncommon chronic cerebrovasculopathy, characterized by progressive stenosis of the terminal portion of the internal carotid artery and its main branches, in association with the development of compensatory collateral vessels at the base of the brain. The etiology is unknown, and was originally considered exclusive to East Asia, with particular prevalence in Japan. Moyamoya disease is increasingly diagnosed throughout the world, and represents an important cause of childhood stroke in Western countries. In some cases, similar angiographic features are evident in children with other medical conditions, such as sickle cell disease and Down syndrome. In these instances, the term "moyamoya syndrome" is used. Diagnosing the vasculopathy, excluding possible associated conditions, and planning treatment and follow-up imaging comprise important aspects of clinical management. We review the key imaging features of childhood moyamoya disease and syndrome, present examples of its associations, and discuss new neuroradiologic methods that may be useful in management.

Quantitative hemodynamic studies in moyamoya disease: a review

Moyamoya disease is characterized by a chronic stenoocclusive vasculopathy affecting the terminal internal carotid arteries. The clinical presentation and outcome of moyamoya disease remain varied based on angiographic studies alone, and much work has been done to study cerebral hemodynamics in this group of patients. The ability to measure cerebral blood flow (CBF) accurately continues to improve with time, and with it a better understanding of the pathophysiological mechanisms in patients with moyamoya disease. The main imaging techniques used to evaluate cerebral hemodynamics include PET, SPECT, xenon-enhanced CT, dynamic perfusion CT, MR imaging with dynamic susceptibility contrast and with arterial spin labeling, and Doppler ultrasonography. More invasive techniques include intraoperative ultrasonography. The authors review the current knowledge of CBF in this group of patients and the role each main quantitative method has played in evaluating them, both in the disease state and after surgical intervention.

Intracranial hemodynamic changes during adult moyamoya disease progression

Background and purpose

This study evaluated the changes in blood flow velocity in the anterior and posterior intracranial circulations according to the progression of moyamoya disease in adult patients.

Methods

We evaluated Suzuki's angiographic stage and mean blood flow velocity (MBFV) changes in intracranial vessels from both sides in 19 adult moyamoya patients. We then analyzed the linearity of MBFV changes from early to late moyamoya stages in each intracranial vessel using piecewise linear regression models.

Results

The MBFV in the middle cerebral artery, terminal internal carotid artery, and anterior cerebral artery increased non linearly until stage III, and then decreased progressively up to stage VI. The ophthalmic artery also showed nonlinear velocity changes, with an increase in MBFV up to stage IV, followed by a decrease in MBFV up to stage VI. The MBFV of the basilar artery increased linearly from a normal velocity at an early moyamoya stage to a stenotic velocity at a late stage. There was no statistically significant regression model for the relationship between the MBFV in the posterior cerebral artery and moyamoya stage.

Conclusions

The nonlinear and/or linear MBFV changes associated with variable intracranial vessels might be useful in initial and follow-up evaluations of different stages of moyamoya disease.

Steal phenomenon through the anterior communicating artery in Moyamoya disease

Branch occlusion of the anterior cerebral artery (ACA) is regarded as a part of Moyamoya disease. The purpose of this study is to define the ACA steal phenomenon (SP) in Moyamoya disease and to evaluate temoporal changes according to the disease progression. From 139 Moyamoya patients we defined ACASP as narrowing of the ipsilateral A1-2 junction while preserving the anterior communicating artery and supplying the contralateral ACA cortical branches with the development of leptomeningeal collaterals by the ipsilateral middle cerebral artery into the hypoperfused ipsilateral ACA territory. Direction of the steal related to the stage in both hemispheres by Suzuki classification was statistically analyzed using the binomial test based on binomial distribution. Follow-ups of ACASP were evaluated in five patients. We identified ACASP in 13 (9%) patients (male:female=7:6, mean age 18 years, range: 2-58 years) of the 139 study patients. The presenting pattern was ischemic in 12 and hemorrhagic in one. The direction of SP occurred from the hemisphere in the lower to the higher stage of Suzuki classification (two-tail P value=0.0002). After revascularization surgery, ACASP disappeared or diminished. ACASP may occur in bilaterally different stages of Moyamoya disease as a transient self-adaptive process. It regresses after revascularization surgery.

Color and power Doppler sonography of extracranial and intracranial arteries in Moyamoya disease

PURPOSE

To study the hemodynamic characteristics of moyamoya disease with color Doppler (CD) and power Doppler (PD) sonography.

METHODS

The hemodynamic parameters of intracranial and extracranial arteries from 17 patients with moyamoya disease confirmed via digital subtraction angiography and 30 healthy controls were studied with conventional and transcranial CD and PD.

RESULTS

The moyamoya vessels were detected as scattered color Doppler signal with low velocity and a low resistance index (RI) at the base of the brain in 10 of the 17 patients. The RI of the common carotid arteries and the internal carotid arteries of the patients was significantly higher, whereas the peak velocity was lower than in controls. The posterior carotid arteries were more frequently involved in children (43.8%) than in adults (5.6%).

CONCLUSIONS

Transcranial CD and PD can be used to demonstrate the stenosis and occlusion of intracranial arteries and the abnormal vascular network at the base of the brain in most cases. Combined with the hemodynamic characteristics of extracranial arteries and the symptoms of the patients, an accurate diagnosis of moyamoya disease could be made in the majority of cases using PD.

Transcranial Doppler blood flow measurement during cesarean section in two patients with cerebral vascular disease

We present two cases of neurovascular disease in pregnancy in which transcranial Doppler was used to assess the status of the cerebral circulation during cesarean section under regional anesthesia. One woman had been found to have moyamoya disease, following a series of transient ischemic attacks during her first pregnancy, which ended in spontaneous abortion. On this occasion she was delivered by cesarean section under slowly-induced epidural anesthesia, using ephedrine to maintain the blood pressure, and transcranial Doppler revealed no change in signal in her left middle cerebral artery. Both mother and baby had an uneventful post natal course. The second case involved a primiparous woman with a large arteriovenous malformation that had been detected following generalized seizures, which were treated with valproic acid. Her cesarean section was conducted under spinal anesthesia, and her blood pressure maintained with ephedrine. Again transcranial Doppler revealed no change in signal in her middle cerebral artery during the procedure. We believe this is a potentially useful technique to monitor the cerebral circulation intraoperatively in the presence of cerebrovascular disease.

[Comparison of the neuropsychological assessment in a girl with bilateral cerebrovascular disease (moyamoya) before and after surgical intervention]

Moyamoya is a chronic progressive cerebrovascular disease with characteristic angiographic findings and a clinical picture with episodes of transient ischemic attacks, headache, seizures, hemiparesis, which may resolve after surgical treatment. We describe the case of a girl with the typical findings of the disease, comparing them before and after surgery with the use of neuropsychological tests, neurological examination and laboratory tests.

An atypical case of adult Moyamoya disease with initial onset of brain stem ischemia

We present an atypical case of adult moyamoya disease whose clinical onset consisted of ischemic symptoms of the brain stem. She initially presented with left hemisensory disturbance caused by a pontine lesion, followed by a myelopathy of the upper cervical spinal cord. Eight months later, she presented with left hemiplegia and disturbed consciousness. Magnetic resonance angiography showed significant narrowing of both horizontal portions of the middle cerebral arteries (M1). Conventional angiography revealed bilateral occlusion of the internal carotid arteries. Her anterior circulation was supplied from the vertebro-basilar system through Moyamoya vessels and leptomeningeal collaterals. The intracranial steal phenomenon was thought to be the reason for the preceding events in the brain stem and upper cervical spinal cord. In addition, transcranial color-coded duplex sonography (TCCS) showed identical findings to conventional angiography with antegrade flow in the proximal M1 and retrograde flow in the distal M1. Thus, TCCS was useful for diagnosing the M1 occlusion in this case of Moyamoya disease.

Transcranial Doppler ultrasonography in patients with moyamoya disease

This study included 17 patients (five men and 12 women) with clinical diagnosis of Moyamoya disease from conventional angiograms. Bilateral basal arteries were measured by the transtemporal approach with a 2 MHz pulsed Doppler instrument (TC-2 64B EME). In 28 out of the 34 basal arteries (82.4%), reliable recordings were obtained. These transcranial Doppler ultrasonography (TCD) findings were classified into three patterns: (1) High-high pattern; the mean cerebral blood flow velocity (CBFV) was increased throughout the basal arteries by over 70 cm/s (seven arteries, 25.0%); (2) high-low pattern; the mean CBFV was fastest (over 70 cm/s) at the ICA or proximal MCA and the mean CBFV decreased remarkably distally (15 arteries, 53.6%); and (3) low-low pattern; the mean CBFV was less than 40 cm/s throughout the basal arteries (arteries, 15.4%). These CBFV patterns as assessed by TCD are compared with the patients age, clinical symptoms and angiographical stagings (Suzuki's criteria). The high-high pattern on TCD was predominantly seen in the younger patients and in the earlier stages of the disease. The high-low pattern was the most common pattern of CBFV as assessed by TCD in Moyamoya patients. The low-low pattern on TCD was more common in the later stages following angiographic evaluation by Suzuki's criteria. The above patterns based on TCD findings show a good correlation with the age of the patient and the clinical diagnosis at the onset. TCD appears to be very useful in the evaluation of patients with Moyamoya disease.