====== Moyamoya Disease Diagnosis ====== {{rss>https://pubmed.ncbi.nlm.nih.gov/rss/search/1VsHRGSo3HXRCjAo_wWUrXBS0-VvMFCEqDl_tdFJeKcEmCbQgS/?limit=15&utm_campaign=pubmed-2&fc=20240220054715}} {{ ::moyamoya.jpg?300|}} [[Diagnosis]] of [[Moyamoya disease]] requires bilateral symmetrical stenosis or occlusion of the terminal portion of the [[internal carotid artery]]s ([[ICA]])s as well as the presence of dilated collateral vessels at the base of the brain ((Smith ER, Scott RM. Surgical management of moyamoya syndrome. Skull Base. 2005; 15:15–26)). (If unilateral, the diagnosis is considered questionable, ((Nishimoto A. Moyamoya Disease. Neurol Med Chir. 1979; 19:221–228)) and these cases may progress to bilateral involvement). Other characteristic findings include: 1. stenosis/occlusion starting at the termination of ICA and at origins of ACA and MCA 2. abnormal vascular network in the region of BG (intraparenchymal anastomosis). 3. transdural anastomosis(rete mirabile), AKA “vault moyamoya.”Contributing arteries: anterior falcial, middle meningeal, ethmoidal, occipital, tentorial, STA 4. moyamoya collaterals may also form from the internal maxillary artery via ethmoid sinus to the forebrain in the frontobasal region. ===== CT ===== Work-up in suspected cases typically begins with a non-enhanced [[head CT]]. Up to 40% of ischemic cases have normal CT. Low-density areas (LDAs) may be seen, usually confined to cortical and [[subcortical]] areas (unlike atherosclerotic disease or acute infantile hemiplegia which tend to have LDAs in [[basal ganglia]] as well). LDAs tend to be multiple and bilateral, especially in the [[PCA]] distribution (poor collaterals), and are more common in children. ===== Magnetic resonance imaging ===== [[Magnetic resonance imaging for Moyamoya Disease Diagnosis]]. ===== Angiography ===== In addition to helping to establish the diagnosis, angiography also identifies suitable vessels for revascularization procedures and unearths associated aneurysms. The angiography-related complication rate is higher than with atherosclerotic occlusive disease. Avoid dehydration prior to and hypotension during the procedure. Six angiographic stages of MMD are described by Suzuki and Takaku ((Suzuki J, Takaku A. Cerebrovascular "moyamoya" disease. Disease showing abnormal net-like vessels in base of brain. Arch Neurol. 1969 Mar;20(3):288-99. PubMed PMID: 5775283. )) that tend to progress up until adolescence and stabilize by age 20. 1 stenosis of suprasellar ICA, usually bilateral 2 development of moyamoya vessels at the base of the brain; ACA MCA & PCA dilated 3 increasing ICA stenosis & prominence of moya-moya vessels (most cases diagnosed at this stage); maximal basal moyamoya 4 entire circle of Willis and PCAs occluded, extracranial collaterals start to appear, moyamoya vessels begin to diminish 5 further progression of stage 4 6 complete absence of moyamoya vessels and major cerebral arteries. ===== EEG ===== Non-specific in the adult. Juvenile cases: high-voltage slow waves may be seen at rest, predominantly in the occipital and frontal lobes. Hyperventilation produces a normal buildup of monophasic slow waves (delta-bursts) that return to normal 20–60 seconds after hyperventilation. In >50%of cases, after or sometimes continuous with buildup is a second phase of slow waves (this characteristic finding is called “rebuild up”) which are more irregular and slower than the earlier waves, and usually, normalize in ≤10 minutes ((Kodama N, Aoki Y, Hiraga H, et al. Electroencephalographic Findings in Children with Moyamoya Disease. Arch Neurol. 1979; 36:16–19)). ===== Cerebral blood flow (CBF) studies ===== CBF is decreased in children with MMD, but relatively normal in adults. There is a shift of CBF from the frontal to the occipital lobes ((Ogawa A, Yoshimoto T, Suzuki J, Sakurai J. Cerebral Blood Flow in Moyamoya Disease. Part 1. Correlation with Age and Regional Distribution. Acta Neurochir. 1990; 105:30–34)) probably reflecting the increasing dependency of CBF on the posterior circulation. Children with MMD have impaired autoregulation of CBF to blood pressure and CO2 (with more impairment of vasodilatation in response to hypercapnia or hypotension than vasoconstriction in response to hypocapnia or hypertension) ((Ogawa A, Nakamura N, Yoshimoto T, Suzuki J. Cerebral Blood Flow in Moyamoya Disease. Part 2. Autoregulation and CO2 Response. Acta Neurochir. 1990; 105:107–111)). Xenon (Xe-133) CT can identify areas of low perfusion. Repeating the study after an acetazolamide challenge (which causes vasodilatation) evaluates the reserve capacity of CBF and can identify areas of “steal” which are at high risk of future infarction. ===== Ultrasound ===== [[Ultrasound]] parameters are independently correlated with ipsilateral [[cerebral]] [[stroke]] in patients with [[Moyamoya disease]] (MMD). [[Ultrasound]] provides a new way to identify stroke in MMD patients. Future [[prospective]] [[cohort]] studies are needed to verify the clinical value of ultrasound in identifying patients with MMD at high risk of stroke ((Zheng S, Wang F, Cheng L, Li R, Zhang D, He W, Zhang W. [[Ultrasound]] parameters associated with [[stroke]] in patients with [[moyamoya disease]]: a [[logistic regression]] analysis. Chin Neurosurg J. 2022 Oct 11;8(1):32. doi: 10.1186/s41016-022-00300-5. PMID: 36221122.)). ===== 18F-FDG PET ===== Vascular [[cognitive impairment]] (VCI) is a critical issue in [[moyamoya disease]] (MMD). However, the glucose metabolic pattern in these patients is still unknown. This study aimed to identify the metabolic signature of cognitive impairment in patients with MMD using [[18F]]-2-fluoro-2-deoxy-D-glucose [[positron emission tomography]] (18F-[[FDG PET]]) and establish a classifier to identify VCI in patients with MMD. One hundred fifty-two patients with MMD who underwent brain 18F-FDG PET scans before surgery were enrolled and classified into nonvascular cognitive impairment (non-VCI, n = 52) and vascular cognitive impairment (VCI, n = 100) groups according to neuropsychological test results. Additionally, thirty-three health controls (HCs) were also enrolled. Compared to HCs, patients in the VCI group exhibited extensive hypometabolism in the bilateral frontal and cingulate regions and hypermetabolism in the bilateral cerebellum, while patients in the non-VCI group showed hypermetabolism only in the cerebellum and slight hypometabolism in the frontal and temporal regions. In addition, we found that the patients in the VCI group showed hypometabolism mainly in the left basal ganglia compared to those in the non-VCI group. The sparse representation-based classifier algorithm taking the SUVr of 116 Anatomical Automatic Labeling (AAL) areas as features distinguished patients in the VCI and non-VCI groups with an accuracy of 82.4%. This study demonstrated a characteristic metabolic pattern that can distinguish patients with MMD without VCI from those with VCI, namely, hypometabolic lesions in the left hemisphere played a more important role in cognitive decline in patients with MMD ((Weng R, Ren S, Su J, Ni W, Yang C, Gao X, Xiao W, Zhang X, Jiang H, Guan Y, Huang Q, Gu Y. 18F-FDG PET and a classifier algorithm reveal a characteristic glucose metabolic pattern in adult patients with moyamoya disease and vascular cognitive impairment. Brain Imaging Behav. 2023 Jan 13. doi: 10.1007/s11682-022-00752-4. Epub ahead of print. PMID: 36637715.)). ===== References =====