Association of distal hyperintense vessel sign and recurrent stroke in patients with symptomatic intracranial stenosis.

OBJECTIVE: The distal hyperintense vessel sign (DHV) on fluid-attenuated inversion recovery magnetic resonance image (MRI) is an imaging biomarker of slow leptomeningeal collateral flow in the presence of large artery stenosis or occlusion reflecting impaired cerebral hemodynamics. In this study, we aim to investigate the significance of the DHV sign in patients with symptomatic ≥ 70% intracranial atherosclerotic stenosis. METHODS: We retrospectively reviewed patients with ischemic stroke or transient ischemic attack admitted to a single center from January 2010 to December 2017. Patients were included if they had symptomatic ≥ 70% atherosclerotic stenosis of the intracranial internal carotid artery or middle cerebral artery. The presence of the DHV sign was evaluated by blinded neuroradiologist and vascular neurologists. Recurrent ischemic stroke in the vascular territory of symptomatic intracranial artery was defined as new neurological deficits with associated neuroimaging findings during the follow up period. RESULTS: A total of 109 patients were included in the study, of which 55 had DHV sign. Average duration of follow up was 297 ± 326 days. Four patients were lost during follow up. Patients with the DHV sign had a higher rate of recurrent ischemic stroke (38%), compared to patients without the DHV sign (17%; p=0.018). In multivariate regression analysis, the presence of DHV sign was an independent predictor of recurrent ischemic stroke. A DHV score of ≥ 2 had a 63% sensitivity and 69% specificity for recurrent ischemic stroke. INTERPRETATION: In patients with severe symptomatic intracranial atherosclerotic stenosis, those with a DHV sign on MRI are at higher risk of recurrent ischemic stroke.

Q-15 Minutes Vital Sign Documentation Is a Poor Surrogate for Assessing Quality of Care After Acute Ischemic Stroke.

OBJECTIVE: Documenting vital signs and National Institutes of Health Stroke Scale (NIHSS) once every 15 minutes after intravenous thrombolytic therapy for acute ischemic stroke is often used as a metric to assess the quality of care. This study explores the association between "once every 15 minutes" documentation and stroke outcomes. METHODS: This is a retrospective study of the first 2 hours of vital signs and NIHSS documentation after thrombolytic stroke therapy. Sociodemographic and clinical data, including NIHSS, temperature, heart rate, systolic blood pressure, diastolic blood pressure, mean arterial blood pressure, and respiratory rate, were abstracted from the medical record. Missing documentation was examined for association with modified Rankin Scale (mRS) scores and neurologic changes. RESULT: Among 84 patients with a mean age of 68.8 years, there were 2276 documented assessments from an expected 3780. There were 104 clinically significant changes in 1 or more index variables. The most commonly missed documentation occurred during interventional radiology. After controlling for admission NIHSS, there was no significant relationship between the completeness of documentation and discharge mRS score (r2 = 0.047, P = .0561), nor between vital sign documentation and discharge mRS (r2 = 0.003, P = .6338). CONCLUSION: Frequency of documentation does not reflect the quality of care during the early phase of acute stroke treatment.

Two Unique Mutations in HTRA1-Related Cerebral Small Vessel Disease in North America and Africa and Literature Review.

OBJECTIVE: To describe and compare two cases of North American and African patients who were diagnosed with HTRA1-related cerebral small vessel disease (CSVD) with homozygous and heterozygous mutations, respectively, in the linker domain of the HTRA1 gene. MATERIALS AND METHODS: Case reports and literature review. RESULTS: A 49-year-old man from Mexico presented with recurrent lacunar strokes and memory loss. A 46-year-old woman from Eritrea presented with progressive memory loss. Neither patient had alopecia. MRI of the brain and spine in both patients showed leukoencephalopathy, microbleeds and spondylosis. Microbleeds along the subpial surfaces of the brainstem were only seen in the Mexican man. Genetic sequencing of HTRA1 gene revealed a novel homozygous mutation of p.A173S in the Mexican man supporting cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL). A heterozygous mutation of p.V175M was detected in the African woman, which has not been reported in patients of African ethnicity. In reviewing literature, CARASIL patients with mutation in the linker domain are older at neurological symptom onset and more frequently presented with stroke compared to patients with non-linker domain mutations. In patients of HTRA1-CSVD from heterozygous mutations, male is more common. CONCLUSIONS: HTRA1-related CSVD may be seen in patients of non-Asian ethnicity without alopecia. These case reports extend the clinical and radiographic spectrum of HTRA1-related CSVD.

Impact of MRI Selection on Triage of Endovascular Therapy in Acute Ischemic Stroke: The MRI in Acute Management of Ischemic Stroke (MIAMIS) Registry.

BACKGROUND: The recently published multicenter randomized DAWN trial confirmed greater outcome benefit of endovascular therapy (ET) for anterior circulation large vessel occlusion ischemic stroke from 6 to 24 h from symptom onset compared to medical management in patients selected by advanced imaging with MRI or perfusion CT to identify mismatch between clinical deficit and infarct volume, which represents salvageable penumbra. The debate of CT over MRI is usually the potentially increase time consumption and the difficulty in establishing an adequate standardized workflow utilizing MRI during the hyperacute phase. PURPOSE: While CT-based selection of patients is the current standard of care, we sought to determine the time impact of the alternative approach of MRI selection in the 0-12 h window. METHODS: In the MRI in Acute Management of Ischemic Stroke (MIAMIS) registry, we retrospectively analyzed 89 consecutive patients from January 2008 to January 2010 who presented with acute stroke symptoms with a National Institutes of Health Stroke Scale score ≥5 or aphasia within 0-12 h from symptom onset. The presence of penumbra was determined by MR perfusion-diffusion mismatch or clinical diffusion mismatch. Patients were stratified based on the presence of mismatch and clinical outcomes in patients who received ET. Imaging times were recorded. RESULTS: The MRI turnaround time was 95.5 ± 48.5 min. The total MRI time was 27.7 ± 12.8 min. Seventeen (19.1%) patients were found to have nonvascular etiology. Mismatch was found in 35 (48.6%) patients with acute ischemic stroke (AIS). Patients with nonvascular etiology were younger (55.7 vs. 65.6 years, p < 0.02), without any vessel occlusion or mismatch noticed in this group. We dichotomized the 39 AIS patients with vessel occlusion into two subgroups: these with mismatch and these without. Patients without mismatch were older (76.7 vs. 64.4 years, p < 0.05), more likely to have congestive heart failure (71.4 vs. 22%, p < 0.03), a higher total serum cholesterol level (196 vs. 156 mg/dL, p < 0.04), and medium to large lesions on diffusion-weighted imaging (DWI) (85.7 vs. 37.5%, p < 0.04). CONCLUSIONS: Multimodality MRI screening for AIS symptoms for ET is feasible. Optimizing each center's protocol and the utilization of MRI with DWI only may be a time-saving alternative.

Prevalence of and Risk Factors for Cerebral Microbleeds in Moyamoya Disease and Syndrome in the American Population.

BACKGROUND AND PURPOSE: Cerebral microbleeds (CMB) are reported to be frequent in moyamoya disease (MMD) and moyamoya syndrome (MMS) in the Asian population. It is associated with an increased risk of intracerebral hemorrhage. The significance of CMB in MMD/MMS in non-Asian populations has not been well established. Our study aimed to investigate the prevalence of CMB in MMD/MMS in a moymoya cohort with a majority of non-Asians and to identify risk factors for developing a CMB and its predictive value for subsequent vascular events. METHODS: The moyamoya database was compiled by screening for MMD/MMS among patients admitted to the Zale-Lipshy University Hospital at the University of Texas Southwestern Medical Center. We identified and analyzed data of 67 patients with MMD or MMS. Patients were characterized as CMB+ or CMB- based on MRI findings. In CMB+ patients, the total number and location of CMB were identified. Univariate and multivariate logistic regression were used to identify risk factors for developing CMB and whether CMB are associated with the development of subsequent vascular events. RESULTS: Out of a total of 67 patients, 11 (16%) had CMB. Males had significantly higher odds of having CMB as compared to females (OR 1.76; 95% CI 1.40-24.3, p = 0.021). The incidence of CMB was also associated with age at diagnosis (mean age of CMB+ patients vs. CMB- patients: 44 vs. 34 years, respectively, p = 0.024), smoking (p = 0.006), and hemorrhagic stroke at presentation (p = 0.034). Logistic regression with multivariate analysis found that gender and age at diagnosis remained statistically significant. New ischemic events occurred in 2 (20%) out of 10 CMB+ patients and 13 (23%) out of 55 CMB- patients, respectively (p = 0.79). While 2 (3%) CMB- patients had a new cerebral hemorrhage during follow-up, none of the CMB+ patients did. CONCLUSIONS: CMB are less prevalent in MMD/MMS in the USA than in Asia. An older age at diagnosis and male gender were associated with CMB. The presence of CMB was not associated with an increased risk of a subsequent ischemic or hemorrhagic stroke.

Unveiling a hidden 31 P signal coresonating with extracellular inorganic phosphate by outer-volume-suppression and localized 31 P MRS in the human brain at 7T.

PURPOSE: The study was undertaken to demonstrate that there is more than 1 component in the extracellular Pi31 P signal ( Piex) acquired from human head using nonlocalized 31 P MRS. METHODS: Outer-volume-suppression (OVS) saturation and 1D/2D 31 P CSI were utilized to reveal the presence of an additional component in the Piex signal. RESULTS: 67% of the head extracellular Pi signal was attenuated upon OVS saturation of the peripheral meningeal tissues, likely reflecting elimination of the Pi signal in the meningeal fluids (the blood and CSF). Localized 1D/2D CSI data provided further support for this assignment. Upon correction for the meningeal contribution, the extracellular Pi concentration was 0.51 ± 0.07 mM, whereas the intracellular Pi was 0.85 ± 0.10 mM. The extracellular pH was measured as 7.32 ± 0.04 when using OVS, as compared to 7.39 ± 0.03 when measured without OVS (N = 7 subjects). CONCLUSION: The extracellular Pi signal acquired from the human head using nonlocalized 31 P MRS contains a significant component likely contributed by peripheral blood and CSF in meninges that must be removed in order to use this signal as an endogenous probe for measuring extracellular pH and other properties in the brain.

Impaired cerebral autoregulation: measurement and application to stroke.

Cerebral autoregulation (CA) is a protective mechanism that maintains cerebral blood flow at a relatively constant level despite fluctuations of cerebral perfusion pressure or arterial blood pressure. It is a universal physiological mechanism that may involve myogenic, neural control as well as metabolic regulations of cerebral vasculature in response to changes in pressure or cerebral blood flow. Traditionally, CA has been represented by a sigmoid curve with a wide plateau between about 50 mm Hg and 170 mm Hg of steady-state changes in mean arterial pressure, defined as static CA. With the advent of transcranial Doppler, measurement of cerebral blood flow in response to transient changes in arterial pressure has been used to assess dynamic CA. However, a gold standard for measuring CA is not currently available. Stroke has been the leading cause of long-term adult disability throughout the world. A better understanding of CA and its response to pathological derangements can help assess the severity of stroke, guide management decisions, assess response to interventions and provide prognostic information. The objective of this review is to provide a comprehensive insight about physiology of autoregulation, measurement methodologies and clinical applications in stroke to help build a consensus for what should be included in an internationally agreed protocol for CA testing and monitoring, and to promote its translation into clinical bedside practice for stroke management.

Bilateral asymmetrical asterixis as limb-shaking transient ischemic attack in bilateral carotid stenosis.

Asterixis as limb-shaking transient ischemic attack (TIA) is rare and poorly understood. Bilateral asymmetrical asterixis as limb-shaking TIA has not been reported in carotid stenosis. A 69-year-old gentleman presented with a TIA episode (dysarthria, right-arm weakness, and numbness). Bilateral asterixis was observed and was more severe on the right side. No prior infarcts were noted in the thalamus. Liver function was normal. A computerized tomography angiogram revealed 85%stenosis of the right internal carotid artery (ICA) and 65% stenosis of the left ICA. Three days after left ICA endarterectomy, the patient had complete disappearance of bilateral asterixis, with the right side showing initial improvement. The bilateral asterixis observed is proposed to be secondary to hemodynamic impairment and hypoperfusion of certain brain territory with resolution on revascularization.