Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Pulsatility index (PI) in the middle cerebral artery (MCA) is considered a measure of peripheral vascular resistance. Several established cardiovascular risk factors are common for both MCA PI and carotid atherosclerosis. Accordingly, in the present study we hypothesized an association between ultrasound-derived indices of carotid atherosclerosis and MCA PI. ⋯ In a population-based sample of middle-aged adults, ultrasound-derived indices of carotid atherosclerosis were independently associated with MCA PI. However, the overall explained variance of MCA PI was low, suggesting other factors than atherosclerosis and cardiovascular risk factors to play an important role for MCA PI.
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In the setting of an extended time window for endovascular treatment (EVT) for acute stroke patients, computed tomography perfusion (CTP) has become a major tool in patient selection. However, there are some data suggesting that the initial ischemic core may be overestimated by CTP depending on stroke onset time. This study aims to evaluate possible predictors of overestimation of infarct core by CTP. ⋯ Over estimation of the infarct core by CTP in patients undergoing EVT is time dependent and so CTP results among early arrivers should be interpreted cautiously.
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Meta Analysis
Quantification of Optic Nerve and Sheath Diameter by Transorbital Sonography: A Systematic Review and Metanalysis.
To date, normal values for optic nerve diameter (OND) and optic nerve sheath diameter (ONSD) for transorbital sonography (TOS) have only been reported by individual small-scale studies, exposing a great variability in the measurement of the OND and ONSD. ⋯ TOS is a frequently described and widely used method. We provide reference values of OND and ONSD that are based on metanalytical analysis. Different measuring methods of ONSD result in higher heterogeneity. Subgroup analysis revealed no significant correlation between ONSD and age, gender, or geographic origin.
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Comparative Study
Noncontrast CT versus Perfusion-Based Core Estimation in Large Vessel Occlusion: The Blood Pressure after Endovascular Stroke Therapy Study.
The 2018 AHA guidelines recommend perfusion imaging to select patients with acute large vessel occlusion (LVO) for thrombectomy in the extended window. However, the relationship between noncontrast CT and CT perfusion imaging has not been sufficiently characterized >6 hours after last known normal (LKN). ⋯ In this multicenter prospective cohort of patients who underwent thrombectomy, one-third of patients had normal CTP core volumes despite nearly three quarters of patients showing ischemic changes on CT. This finding emphasizes the need to carefully assess both noncontrast and perfusion imaging when considering thrombectomy eligibility.
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Cerebral vasospasm in the setting of subarachnoid hemorrhage causes morbidity and mortality due to delayed cerebral ischemia and permanent neurological deficits. Vasospasm treatment includes intra-arterial injection of a spasmolytic during cerebral angiography. To evaluate effectiveness, neurointerventionalists subjectively examine a posttreatment cerebral angiogram to determine change in vessel diameter or increase in microvascular perfusion. Flat-detector computed tomography (FDCT) scanner has the ability to quantitatively measure cerebral blood volume (CBV) within the parenchyma and detect a quantitative change following treatment. ⋯ In conclusion, FDCT could measure the effectiveness of a change in CBV from infusion of verapamil in the setting of cerebral vasospasm. The authors believe quantifying the change allows for reassurance of improvement of cerebral vasospasm.