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Background: Hyperintense vessels (HVs) on fluid-attenuated inversion recovery (FLAIR) are frequently observed in acute ischemic stroke (AIS). The presence of HVs represents altered blood flow from collaterals distal to arterial occlusion or stenosis. This study aimed to evaluate the prognostic value of HVs in AIS. Methods: Fifty-four consecutive patients with acute middle cerebral artery occlusion were enrolled in the study. The location and extent of the HVs was determined by FLAIR. Clinical data were obtained and compared between patients with different grades of HVs. Additionally, the relationship between distal HVs and leptomeningeal collaterals (LMCs) was assessed using angiography. Results: HVs were observed in 41 (75.9%) of the 54 patients enrolled. The initial NIHSS score was lower (p < 0.001) and the infarction volume was smaller (p < 0.001) in patients with distal HVs. Adjusting of other factors, regression analysis revealed that distal HVs are an independent predictor of a favorable outcome at 90 days (p = 0.006; OR 0.049; 95% CI 0.006-0.420). Furthermore, the presence of distal HVs was correlated with the presence of LMCs. Conclusion: Distal HVs may be a marker for LMCs and act as a predictor of a favorable clinical outcome for patients with AIS. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background and Purpose: In acute stroke it is no longer sufficient to detect simply ischemia, but also to try to evaluate reperfusion/recanalization status and predict eventual hemorrhagic transformation. Arterial spin labeling (ASL) perfusion may have advantages over contrast-enhanced perfusion-weighted imaging (cePWI), and susceptibility weighted imaging (SWI) has an intrinsic sensitivity to paramagnetic effects in addition to its ability to detect small areas of bleeding and hemorrhage. We want to determine here if their combined use in acute stroke and stroke follow-up at 3T could bring new insight into the diagnosis and prognosis of stroke leading to eventual improved patient management. Methods: We prospectively examined 41 patients admitted for acute stroke (NIHSS >1). Early imaging was performed between 1 h and 2 weeks. The imaging protocol included ASL, cePWI, SWI, T2 and diffusion tensor imaging (DTI), in addition to standard stroke protocol. Results: We saw four kinds of imaging patterns based on ASL and SWI: patients with either hypoperfusion and hyperperfusion on ASL with or without changes on SWI. Hyperperfusion was observed on ASL in 12/41 cases, with hyperperfusion status that was not evident on conventional cePWI images. Signs of hemorrhage or blood-brain barrier breakdown were visible on SWI in 15/41 cases, not always resulting in poor outcome (2/15 were scored mRS = 0-6). Early SWI changes, together with hypoperfusion, were associated with the occurrence of hemorrhage. Hyperperfusion on ASL, even when associated with hemorrhage detected on SWI, resulted in good outcome. Hyperperfusion predicted a better outcome than hypoperfusion (p = 0.0148). Conclusions: ASL is able to detect acute-stage hyperperfusion corresponding to luxury perfusion previously reported by PET studies. The presence of hyperperfusion on ASL-type perfusion seems indicative of reperfusion/collateral flow that is protective of hemorrhagic transformation and a marker of favorable tissue outcome. The combination of hypoperfusion and changes on SWI seems on the other hand to predict hemorrhage and/or poor outcome. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background/Aims: Stiff arteries cause high pulse pressure and flow to be transmitted to distal organs during systole, damaging the cerebral microvasculatures. We investigated the association between the severity of cerebral small vessel disease (CSVD), the pulsatility of cerebral arteries, and the stiffness of large arteries in patients with lacunar infarction (LI). Methods: Subjects included 120 patients with LIs, who underwent MRI, transcranial Doppler ultrasonography, and brachial ankle pulse wave velocity (BaPWV). We compared the severity of CSVD, the pulsatile index (PI) of both middle cerebral arteries (MCAs), and BaPWV. Results: Patients with higher BaPWV were more likely to have multiple LIs and more severe white matter lesions, and tended to have higher age, systolic blood pressure, pulse pressure, heart rate, and the PI of MCAs. The PI of MCAs significantly correlated with BaPWV (with PI: r = 0.441, p < 0.001) and age (with PI: r = 0.538, p < 0.001). Multiple linear regression analysis indicated that aging (β = 0.008, p < 0.001) and BaPWV (β = 0.001, p = 0.007) were independent determinants of the PI of MCAs after adjustment for sex, pulse pressure, hypertension, and diabetes. Conclusion: These findings suggest that systemic arterial stiffness may be associated with the severity of CSVD and pulsatility of cerebral arteries. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Objectives: Cerebral arteriovenous malformations (AVMs) harbor a network of abnormal vasculatures, namely the nidus between arterial and venous components. The pressure gradient between these two components results in abnormal high-velocity arteriovenous shunts flowing through the nidus and alternate intracranial hemodynamics. This study hypothesizes that the flow patterns of the circle of Willis (CoW) are modulated by the alternation of intracranial hemodynamics occurring in cerebral AVMs. The flow patterns of the CoW before and after AVMs had been corrected and the arteriovenous shunts closed by radiosurgery were assessed to validate the hypothesis. Patients and Methods: Fifty patients (32 men and 18 women; mean age 35.8 ± 4.2, range 23–52 years) with cerebral AVMs previously treated by radiosurgery were retrospectively investigated. This investigation used magnetic resonance angiography, performed prior to and after AVM surgery, to assess the CoW flow patterns. Results: The CoW flow patterns in nearly half of the subjects (20/50, 40%) altered after the AVMs had been corrected. The alterations included: (1) decreased size or ceased flow patterns in the CoW vascular segment: ipsilateral A1 (n = 1) of the anterior cerebral artery (ACA), ipsilateral posterior communicating artery (PCoA) segment (n = 7), contralateral PCoA collateral (n = 4), bilateral PCoA (n = 2); (2) increased size or opening of the previous ‘hypoplastic’ segment of CoW: ipsilateral A1 of ACA (n = 1), contralateral PCoA (n = 2), bilateral PCoA (n = 1), and (3) biphasic alteration of the CoW: ceased ipsilateral PCoA segment and opening ipsilateral A1 of the ACA (n = 1), ceased ipsilateral PCoA and opening contralateral P1 of the posterior cerebral artery (n = 1). Conclusion: The plasticity of the flow patterns in the CoW are modulated by intracranial hemodynamics as shown by the AVM model. The calibers of CoW arterial segments are not a static feature. Willisian collateralization with recruitment of the CoW segment may cease, or hypoplastic segments may reopen after closing arteriovenous shunts of the AVM. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: We hypothesized that perforator territory infarcts in the lenticulostriate territory (pLSAIs) may have heterogeneous lesion patterns and stroke mechanisms. Methods: We reviewed prospectively collected patients who developed pLSAIs within 72 h after stroke onset. Lesion patterns were analyzed based on the six axial levels. Based on MR angiography, stenosis of the middle cerebral artery (MCA) was classified into 3 groups. White matter hyperintensities were assessed by Fazeka’s scale of periventricular hyperintensity (PVH) and deep white matter hyperintensity (DWMH). Results: Of 221 patients, 159 were normal, 44 had mild stenosis, and 18 had severe stenosis of the MCA. Larger infarct volume was correlated with the severity of MCA disease (r = 0.289, p < 0.001). Lower lesion patterns were correlated with the severity of MCA disease (r = –0.294, p < 0.001). A higher lesion pattern was correlated with the severity of DWMH or PVH scores (r = 0.205, p = 0.002 in DWMH, and r = 0.137, p = 0.042 in PVH). Conclusions: Patients with MCA disease have larger and lower lesion patterns beginning from the proximal territory of the lenticulostriate artery (LSA). Patients with severe white matter changes have smaller and higher lesion patterns in the distal territory of the LSA. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Anterior cerebral artery A1 segment hypoplasia is an uncommon fetal variant of the circle of Willis. The frequency of this congenital variation is 1–13% as derived from angiograms and autopsy reports. Impaired collateral blood flow through the circle of Willis is a recognized risk factor for ischemic stroke. The A1 segment of the anterior cerebral artery is a principal supplier of anterior collateral blood flow. The aim of our study was to determine whether A1 segment hypoplasia may be responsible for acute ischemic stroke. We consecutively examined 280 acute ischemic stroke patients (aged 66.9 ± 14.2 years). Cerebral magnetic resonance angiography was performed within 72 h of ischemic stroke onset. The overall incidence of A1 variation in our experimental group was 15.0% (n = 42, agenesis/hypoplasia = 18/24), which was statistically higher than in the control group (n = 12). The majority (n = 30, 71.42%) had ipsilateral striatal lacunar infarctions. Based on our results, A1 agenesis/hypoplasia appears to be a risk factor contributing to ischemic stroke, especially to strokes in arteries penetrating the striatal area. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Reports on the role of neurologist Charles Edward Beevor in the discovery of Beevor’s sign. Reasons behind the development of the sign; Concentration of efforts on the topical localization of cerebral functions; Awards received for his interests in cerebral localization and the arterial supply of the brain.