BACKGROUND AND PURPOSE—In malignant infarction, brain edema leads to secondary neurological deterioration and poor outcome. We sought to determine whether swelling is associated with outcome in ...smaller volume strokes.
METHODS—Two research cohorts of acute stroke subjects with serial brain MRI were analyzed. The categorical presence of swelling and infarct growth was assessed on diffusion-weighted imaging (DWI) by comparing baseline and follow-up scans. The increase in stroke volume (ΔDWI) was then subdivided into swelling and infarct growth volumes using region-of-interest analysis. The relationship of these imaging markers with outcome was evaluated in univariable and multivariable regression.
RESULTS—The presence of swelling independently predicted worse outcome after adjustment for age, National Institutes of Health Stroke Scale, admission glucose, and baseline DWI volume (odds ratio, 4.55; 95% confidence interval, 1.21–18.9; P<0.02). Volumetric analysis confirmed that ΔDWI was associated with outcome (odds ratio, 4.29; 95% confidence interval, 2.00–11.5; P<0.001). After partitioning ΔDWI into swelling and infarct growth volumetrically, swelling remained an independent predictor of poor outcome (odds ratio, 1.09; 95% confidence interval, 1.03–1.17; P<0.005). Larger infarct growth was also associated with poor outcome (odds ratio, 7.05; 95% confidence interval, 1.04–143; P<0.045), although small infarct growth was not. The severity of cytotoxic injury measured on apparent diffusion coefficient maps was associated with swelling, whereas the perfusion deficit volume was associated with infarct growth.
CONCLUSIONS—Swelling and infarct growth each contribute to total stroke lesion growth in the days after stroke. Swelling is an independent predictor of poor outcome, with a brain swelling volume of ≥11 mL identified as the threshold with greatest sensitivity and specificity for predicting poor outcome.
Selected patients with large vessel occlusions (LVO) can benefit from thrombectomy up to 24 hours after onset. Identifying patients who might benefit from late intervention after transfer from ...community hospitals to thrombectomy-capable centers would be valuable. We searched for presentation biomarkers to identify such patients. Frequent MR imaging over 2 days of 38 untreated LVO patients revealed logarithmic growth of the ischemic infarct core. In 24 patients with terminal internal carotid artery or the proximal middle cerebral artery occlusions we found that an infarct core growth rate (IGR) <4.1 ml/hr and initial infarct core volumes (ICV) <19.9 ml had accuracies >89% for identifying patients who would still have a core of <50 ml 24 hours after stroke onset, a core size that should predict favorable outcomes with thrombectomy. Published reports indicate that up to half of all LVO stroke patients have an IGR <4.1 ml/hr. Other potentially useful biomarkers include the NIHSS and the perfusion measurements MTT and Tmax. We conclude that many LVO patients have a stroke physiology that is favorable for late intervention, and that there are biomarkers that can accurately identify them at early time points as suitable for transfer for intervention.
Abstract only Purpose: To analyze the dynamics of diffusion lesion volumes within the first 48 hours after stroke onset in patients with major anterior circulation occlusions (ACOs). Methods: ...Diffusion ischemic lesion volumes were serially measured in 50 patients that had MRI performed at baseline (~4 hours post ictus) and 2 or 3 additional MRI exams (~12, ~24, ~48 hours post ictus). Thirty eight of these patients had documented major ACOs (terminal internal carotid or proximal middle cerebral artery). Average rate of lesion growth was calculated at each time interval. Functional outcomes (3-month modified Rankin Scale) were correlated to admission NIHSS, DWI volumes and initial lesion growth rates. Results: DWI lesion growth in ACOs was nonlinear over 48 hours and exhibited a logarithmic pattern. The lesion growth rates were highest during earliest period (11.4 ml/hr) and declined during at the 5-12 (0.8 ml/hr ), 12-24 (1.9 ml/hr) and 24-48 hour (0.9 ml/hr) periods. In 23/38 patients there was little or no growth during 5-12 hours period despite continued presence of occlusion in over half of these patients. However, 12/38 experienced >30% growth of lesion during this period, with nearly all patients having persistent occlusions. Functional outcomes correlated with baseline NIHSS and DWI lesion size, as well as initial average growth rate, but only the latter was an independent predictor Conclusions: The growth of ischemic DWI lesions caused by occlusion of major anterior circulation arteries is nonlinear and typically logarithmic. The rate of growth at the earliest time period is a strong predictor of functional outcomes. There is high variability in growth rates due to site of occlusion and most likely the quality of collateral flow. Our results have implications for "Time is Brain."
Abstract only Introduction: In malignant infarction, brain edema leads to secondary neurological deterioration and poor outcome. We investigated whether swelling is associated with outcome in a ...broader range of stroke severity. Methods: Two research cohorts (NBO and EPITHET) comprising 98 acute stroke subjects with prospective serial brain magnetic resonance imaging (MRI) were analyzed. The categorical presence of swelling and/or infarct growth (IG) was assessed on diffusion weighted MRI (DWI) by comparing baseline and 3-5 day follow-up scans. IG was defined using the ASPECTS system (small IG = decrease in ASPECTS ≥ 1; large IG = decrease in ASPECTS ≥ 2). The increase in lesion volume (ΔDWI) was then subdivided into swelling and IG volumes using region-of-interest analysis. The relationship of these imaging markers with outcome was evaluated using univariate and multivariate regression, with poor outcome defined as a 90 day modified Rankin Scale score of 3-6. Receiver operating characteristic (ROC) curve analysis was undertaken to define a threshold for prediction of poor outcome. Results: The presence of swelling independently predicted poor outcome after adjustment for age, admission NIH stroke scale score, admission glucose, and baseline DWI volume (OR4.55, 95%CI 1.21-18.9, p<0.02). Volumetric analysis confirmed ΔDWI was associated with outcome (OR4.29, 95%CI 2.00-11.5, p<0.001). After separating ΔDWI into swelling and IG volumes, swelling remained an independent predictor of poor outcome (OR1.15, 95%CI 1.02-1.43, p<0.02). While large IG was associated with poor outcome (OR7.05, 95%CI 1.04-143, p=0.045), small IG was not. ROC curve analysis identified a swelling volume of ≥11mL as the threshold with greatest sensitivity (77%) and specificity (75%) for predicting poor outcome (AUC=0.798). Conclusions: Both swelling and IG contribute to total lesion growth in the days following stroke. Swelling is an independent predictor of poor outcome in moderate to severe stroke.
•White matter hyperintensity (WMH) burden is a potent stroke risk factor.•Use of clinical MRI scans in research is fraught with methodological limitations.•Novel volumetric method overcomes ...limitations to quantify WMH in stroke patients.•It correlates highly with gold standard and is specific for WMH in ischemic stroke.•Accuracy of clinical MRI assessment is important for future large-scale studies.
Accurate and reliable measurement of leukoaraiosis, or MR-detected white, matter hyperintensity (WMH) burden in subjects with acute ischemic stroke (AIS) is important for, ongoing research studies and future models of risk and outcome prediction, but the presence of a, cerebral infarct may complicate measurement. We sought to assess accuracy of a volumetric method, designed to measure WMH in AIS subjects as compared to the previously validated protocol.
We randomly selected and equally sampled 120 brain scans from the Atherosclerosis, Risk in Communities (ARIC) MRI Study individuals within designated mild, moderate, and severe, tertiles of WMH volume (WMHV). T2 FLAIR axial images were analyzed using the AIS WMH volumetric, protocol and compared with the ARIC (gold standard) method. Pearson correlation coefficients, linear, concordance correlation coefficient, and Blant–Altman procedures were used to assess measurement, agreements between the two procedures.
Median WMHV determined by using the ARIC method was 7.8cm3 (IQR 5.7–13.55) vs. 3.54cm3, (IQR 2.1–7.2) using the AIS WMH method. There was good correlation between the two measurements, (r=0.52, 0.67, and 0.9 for tertiles 1, 2, and 3 respectively) (p<0.001).
The AIS WMH protocol was specific for leukoaraiosis in ischemic, stroke, but it appeared to underestimate WMHV compared to the gold standard method.
Estimates of MR-detectable WMH burden using a volumetric protocol designed for, analysis of clinical scans correlate strongly with gold standard measurements. These findings will, facilitate future studies of WMH in normal aging and in patients with stroke and other cerebrovascular, disease.
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