Introduction. Noncontrast head CT (NCCT) is the standard radiologic test for patients presenting with acute stroke. Early ischemic changes (EIC) are often overlooked on initial NCCT. We determine the sensitivity and specificity of improved EIC detection by a standardized method of image evaluation (Stroke Windows). Methods. We performed a retrospective chart review to identify patients with acute ischemic stroke who had NCCT at presentation. EIC was defined by the presence of hyperdense MCA/basilar artery sign; sulcal effacement; basal ganglia/subcortical hypodensity; and loss of cortical gray-white differentiation. NCCT was reviewed with standard window settings and with specialized Stroke Windows. Results. Fifty patients (42% females, 58% males) with a mean NIHSS of 13.4 were identified. EIC was detected in 9 patients with standard windows, while EIC was detected using Stroke Windows in 35 patients (18% versus 70%; ). Hyperdense MCA sign was the most commonly reported EIC; it was better detected with Stroke Windows (14% and 36%; ). Detection of the remaining EIC also improved with Stroke Windows (6% and 46%; ). Conclusions. Detection of EIC has important implications in diagnosis and treatment of acute ischemic stroke. Utilization of Stroke Windows significantly improved detection of EIC. 1. Introduction Noncontrast head CT (NCCT) is the first-line diagnostic test for emergency evaluation of acute stroke due to its speed of imaging, widespread availability, and low cost. The window width and center level settings—measured in Hounsfield units: HUs—used for computed tomographic (CT) scan review are known to influence both lesion conspicuity and diagnostic accuracy [1]. Numerous studies suggest that detection of early ischemic change (EIC) on NCCT can predict both functional outcome and the risk of intracranial hemorrhage (ICH) [2–4]. Specific features relevant to stroke assessment include hyperdense middle cerebral artery (MCA)/basilar signs, focal parenchymal hypoattenuation (notably of the insular ribbon or lenticular nuclei for MCA infarcts), and cerebral swelling manifested by sulcal or ventricular effacement or loss of cortical grey-white differentiation [5–7]. Decreases in CT attenuation accompanying early stroke are small; therefore, their conspicuity may be increased by using narrow window settings centered at approximately the mean attenuation in HUs of gray and white matter. We believe that the increase in lesion conspicuity achieved with this method can improve the accuracy of nonenhanced CT stroke detection [1]. In most academic stroke
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