BACKGROUND AND PURPOSE:Clot extent, location, and collateral integrity are important determinants of outcome in acute stroke. We hypothesized that a novel clot burden score (CBS) and collateral score (CS) are important determinants of clinical and radiologic outcomes and serve as useful additional stroke outcome predictors.

Background and Purpose-Morbidity and mortality in spontaneous intracerebral hemorrhage (ICH) are correlated with hematoma progression. We hypothesized that the presence of tiny, enhancing foci ("spot sign") within acute hematomas is associated with hematoma expansion. Methods-We prospectively studied 39 consecutive patients with spontaneous ICH by computed tomography angiography within 3 hours of symptom onset. Scans were reviewed by 3 readers. Patients were dichotomized according to the presence or absence of the spot sign. Clinical and radiological outcomes were compared between groups. The predictive value of this sign was assessed in a multivariate analysis. Results-Thirteen patients (33%) demonstrated 31 enhancing foci. Baseline clinical variables were similar in both groups.Hematoma expansion occurred in 11 patients (28%) on follow-up. Seventy-seven percent of patients with and 4% without hematoma expansion demonstrated the spot sign (PϽ0.0001). Sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio for expansion were 91%, 89%, 77%, 96%, and 8.5, respectively. Interobserver agreement was high (ϭ0.92 to 0.94). In patients with the spot sign, mean volume change was greater (Pϭ0.008), extravasation more common (Pϭ0.0005), and median hospital stay longer (Pϭ0.04), and fewer patients achieved a good outcome (modified Rankin Scale score Ͻ2), although the latter was not significant (Pϭ0.16). No differences in hydrocephalus (Pϭ1.00), surgical intervention (Pϭ1.00), or death (Pϭ0.60) were noted between groups. In multiple regression, the spot sign independently predicted hematoma expansion (Pϭ0.0003). Conclusions-The computed tomography angiography spot sign is associated with the presence and extent of hematoma progression. Fewer patients achieve a good clinical outcome and hospital stay was longer. Further studies are warranted to validate the ability of this sign to predict clinical outcomes.

Background and Purpose-We investigated whether computed tomography (CT) perfusion-derived cerebral blood flow (CBF) and cerebral blood volume (CBV) could be used to differentiate between penumbra and infarcted gray matter in a limited, exploratory sample of acute stroke patients. Methods-Thirty patients underwent a noncontrast CT (NCCT), CT angiography (CTA), and CT perfusion (CTP) scan within 7 hours of stroke onset, NCCT and CTA at 24 hours, and NCCT at 5 to 7 days. Twenty-five patients met the criteria for inclusion and were subsequently divided into 2 groups: those with recanalization at 24 hours (nϭ16) and those without (nϭ9). Penumbra was operationally defined as tissue with an admission CBF Ͻ25 mL ⅐ 100 g Ϫ1 ⅐ min

The use of magnetic resonance (MR) imaging is growing exponentially, in part because of the excellent anatomic and pathologic detail provided by the modality and because of recent technologic advances that have led to faster acquisition times. Radiology residents now are introduced in their 1st year of training to the MR pulse sequences routinely used in clinical imaging, including various spin-echo, gradient-echo, inversion-recovery, echo-planar imaging, and MR angiographic sequences. However, to make optimal use of these techniques, radiologists also need a basic knowledge of the physics of MR imaging, including T1 recovery, T2 and T2* decay, repetition time, echo time, and chemical shift effects. In addition, an understanding of contrast weighting is very helpful to obtain better depiction of specific tissues for the diagnosis of various pathologic processes.

BACKGROUND AND PURPOSE:Qualitative CT perfusion (CTP) assessment by using the Alberta Stroke Program Early CT Score (ASPECTS) allows rapid calculation of infarct extent for middle cerebral artery infarcts. Published thresholds exist for noncontrast CT (NCCT) ASPECTS, which may distinguish outcome/complication risk, but early ischemic signs are difficult to detect. We hypothesized that different ASPECTS thresholds exist for CTP parameters versus NCCT and that these may be superior at predicting clinical and radiologic outcome in the acute setting.

Because individuals develop dementia as a manifestation of neurodegenerative or neurovascular disorder, there is a need to develop reliable approaches to their identification. We are undertaking an observational study (Ontario Neurodegenerative Disease Research Initiative [ONDRI]) that includes genomics, neuroimaging, and assessments of cognition as well as language, speech, gait, retinal imaging, and eye tracking. Disorders studied include Alzheimer's disease, amyotrophic lateral sclerosis, frontotemporal dementia, Parkinson's disease, and vascular cognitive impairment. Data from ONDRI will be collected into the Brain-CODE database to facilitate correlative analysis. ONDRI will provide a repertoire of endophenotyped individuals that will be a unique, publicly available resource.RÉSUMÉ: L'initiative de recherche sur les maladies neurodégénératives en Ontario. La démence constituant la manifestation d'un trouble neurodégénératif ou neurovasculaire, il importe de mettre au point des approches fiables permettant son identification. Nous somme ainsi en train de mener une étude observationnelle -Initiative de recherche sur les maladies neurodégénératives en Ontario ou « ONDRI » -qui inclut l'analyse du génome, la neuro-imagerie et diverses techniques d'évaluation en lien avec les aspects suivants : la cognition, le langage, la démarche, l'imagerie rétinienne et le suivi du regard. Parmi les affections à l'étude, on peut mentionner la maladie d'Alzheimer, la sclérose latérale amyotrophique, la démence fronto-temporale, la maladie de Parkinson et la déficience cognitive vasculaire. Les données de l'ONDRI seront recueillies à partir de la base de données du Brain-CODE afin de faciliter les analyses de corrélation. De plus, l'ONDRI entend fournir un répertoire des endophénotypes associés aux sujets de recherche, répertoire unique en son genre qui sera accessible au public.

Purpose:To determine whether admission computed tomography (CT) perfusion-derived permeability-surface area product (PS) maps differ between patients with hemorrhagic acute stroke and those with nonhemorrhagic acute stroke. Materials and Methods:This prospective study was institutional review board approved, and all participants gave written informed consent. Forty-one patients who presented with acute stroke within 3 hours after stroke symptom onset underwent two-phase CT perfusion imaging, which enabled PS measurement. Patients were assigned to groups according to whether they had hemorrhage transformation (HT) at follow-up magnetic resonance (MR) imaging and CT and/or whether they received tissue plasminogen activator (TPA) treatment. Clinical, demographic, and CT perfusion variables were compared between the HT and non-HT patient groups. Associations between PS and HT were tested at univariate and multivariate logistic regression analyses and receiver operating characteristic (ROC) analysis. Results:HT developed in 23 (56%) patients. Patients with HT had higher National Institutes of Health Stroke Scale (NIHSS) scores (P ϭ .005), poorer outcomes (P ϭ .001), and a higher likelihood of having received TPA (P ϭ .005) compared with patients without HT. Baseline blood flow (P ϭ .17) and blood volume (P ϭ .11) defects and extent of flow reduction (P ϭ .27) were comparable between the two groups. The mean PS for the HT group, 0.49 mL ⅐ min Ϫ1 ⅐ (100 g) Ϫ1 , was significantly higher than that for the non-HT group, 0.09 mL ⅐ min Ϫ1 ⅐ (100 g) Ϫ1 (P Ͻ .0001). PS (odds ratio, 3.5; 95% confidence interval [CI]: 1.69, 7.06; P ϭ .0007) and size of hypoattenuating area at nonenhanced admission CT (odds ratio, 0.4; 95% CI: 0.2, 0.7; P ϭ .002) were the only independent variables associated with HT at stepwise multivariate analysis. The mean area under the ROC curve was 0.918 (95% CI: 0.828, 1.00). The PS threshold of 0.23 mL ⅐ min Ϫ1 ⅐ (100 g) Ϫ1 had 77% sensitivity and 94% specificity for detection of HT. Conclusion:Admission PS measurement appears promising for distinguishing patients with acute stroke who are likely from those who are not likely to develop HT.

A comprehensive CT acute stroke protocol delivered a mean effective dose of 16.4 mSv, which is approximately six times the dose of an unenhanced CT head. These high-dose results must be balanced with the benefits of the detailed anatomic and physiologic data obtained. Centers should implement aggressive dose reduction strategies and freely use MR as a substitute.