Malignant profile detected by CT angiographic information predicts poor prognosis despite thrombolysis within three hours from symptom onset.

OBJECTIVE: A malignant profile of early brain ischemia has been demonstrated in the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution (DEFUSE) trial. Patients with a malignant profile had a low chance for an independent functional outcome despite thrombolysis within 3-6 h. We sought to determine whether CT angiography (CTA) could identify a malignant imaging profile within 3 h from symptom onset. METHODS: We studied consecutive patients (04/02-09/07) with anterior circulation stroke who received CTA before intravenous thrombolysis within 3 h. We assessed the Alberta Stroke Program Early CT Score (ASPECTS) on CTA source images (CTASI). Intracranial thrombus burden on CTA was assessed with a novel 10-point clot burden score (CBS). We analyzed percentages independent (modified Rankin Scale score < or =2) and fatal outcome at 3 months and parenchymal hematoma rates across categorized combined CTASI-ASPECTS + CBS score groups where 20 is best and 0 is worst. RESULTS: We identified 114 patients (median age 73 years [interquartile range 61-80], onset-to-tPA time 129 min [95-152]). Among 24 patients (21%) with extensive hypoattenuation on CTASI and extensive thrombus burden (combined score < or =10), only 4% (1/24) were functionally independent whereas mortality was 50% (12/24). In contrast, 57% (51/90) of patients with less affected scores (combined score 11-20) were functionally independent and mortality was 10% (9/90; p < 0.001). Parenchymal hematoma rates were 30% (7/23) vs. 8% (7/88), respectively (p = 0.008). CONCLUSION: CTA identifies a large hyperacute stroke population with high mortality and low likelihood for independent functional outcome despite early thrombolysis.

Reliability of measuring lesion volumes in transient ischemic attack and minor stroke.

BACKGROUND AND PURPOSE: Lesion volume measurements in disabling ischemic stroke have excellent reliability, but it is not clear whether this is also true for small lesions. We assessed the reliability of measuring baseline and follow-up lesion volumes in transient ischemic attack and minor stroke. METHODS: Patients who presented with a transient ischemic attack or minor stroke (NIHSS < or = 3) who had brain MRI within 24 hours from symptom onset and at 30-day follow-up and had an acute lesion on baseline MRI were included. Using semiautomated software, 4 stroke fellows independently assessed ischemic lesions twice on acute diffusion-weighted imaging and follow-up fluid-attenuated inversion recovery. RESULTS: Eighty patients were included, with a median baseline NIHSS of 1. Mean baseline diffusion-weighted imaging lesion volume was 3.4+/-7.4 mL (87.5% had <5 mL). There was excellent inter-rater/intrarater reliability, with intraclass correlation coefficients of 0.94/0.96 for acute diffusion-weighted imaging, 0.74/0.92 for follow-up fluid-attenuated inversion recovery, and 0.81/0.93 for growth. CONCLUSIONS: We found excellent concordance between and within raters for acute diffusion-weighted imaging and 30-day follow-up fluid-attenuated inversion recovery lesion volume measurements in patients with transient ischemic attack and minor stroke.

Atlas-based topographical scoring for magnetic resonance imaging of acute stroke.

BACKGROUND AND PURPOSE: The Alberta Stroke Program Early CT Score (ASPECTS), a 10-point scale, is a clinical tool for assessment of early ischemic changes after stroke based on the location and extent of a visible stroke lesion. It has been extended for use with MR diffusion-weighted imaging. The purpose of this work was to automate a MR topographical score (MR-TS) using a digital atlas to develop an objective tool for large-scale analyses and possibly reduce interrater variability and slice orientation differences. METHODS: We assessed 30 patients with acute ischemic stroke with a diffusion lesion who provided informed consent. Patients were imaged by CT and MRI within 24 hours of symptom onset. An MR-TS digital atlas was generated using the ASPECTS scoring sheet and anatomic MR data sets. Automated MR topographical scores (auto-MR-TS) were obtained based on the overlap of lesions on apparent diffusion coefficient maps with MR-TS atlas regions. Auto-MR-TS scores were then compared with scores derived manually (man-MR-TS) and with conventional CT ASPECTS scores. RESULTS: Of the 30 patients, 29 were assessed with auto-MR-TS. Auto-MR-TS was significantly lower than CT ASPECTS (P<0.001), but with a median difference of only 1 point. There was no significant difference between the auto-MR-TS and the man-MR-TS with a median difference of 0 points; 86% of patient scores differed by

Effects of modafinil on working memory processes in humans.

RATIONALE: Modafinil is a well-tolerated psychostimulant drug with low addictive potential that is used to treat patients with narcolepsy or attention deficit disorders and to enhance vigilance in sleep-deprived military personal. So far, understanding of the cognitive enhancing effects of modafinil and the relevant neurobiological mechanisms are incomplete. OBJECTIVES: The aim of this study was to investigate the effects of modafinil on working memory processes in humans and how they are related to noradrenergic stimulation of the prefrontal cortex. METHODS: Sixteen healthy volunteers (aged 20-29 years) received either modafinil 200 mg or placebo using a double blind crossover design. Two computerized working memory tasks were administered, a numeric manipulation task that requires short-term maintenance of digit-sequences and different degrees of manipulation as well as delayed matching task that assesses maintenance of visuo-spatial information over varying delay lengths. The battery was supplemented by standardized paper pencil tasks of attentional functions. RESULTS: Modafinil significantly reduced error rates in the long delay condition of the visuo-spatial task and in the manipulation conditions, but not in the maintenance condition of the numeric task. Analyses of reaction times showed no speed-accuracy trade-off. Attentional control tasks (letter cancellation, trail-making, catch trials) were not affected by modafinil. CONCLUSIONS: In healthy volunteers without sleep deprivation modafinil has subtle stimulating effects on maintenance and manipulation processes in relatively difficult and monotonous working memory tasks, especially in lower performing subjects. Overlapping attentional and working memory processes have to be considered when studying the noradrenergic modulation of the prefrontal cortex.