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Background and Purpose-Quantification of early ischemic changes (EIC) may predict functional outcome in patients with basilar artery occlusion (BAO). We tested the validity of a novel CT score, the posterior circulation Acute Stroke Prognosis Early CT score (pc-ASPECTS). Methods-Pc-ASPECTS allots the posterior circulation 10 points. Two points each are subtracted for EIC in midbrain or pons and 1 point each for EIC in left or right thalamus, cerebellum or PCA-territory, respectively. We studied 2 different populations: (1) patients with suspected vertebrobasilar ischemia and (2) patients with BAO. We applied pc-ASPECTS to noncontrast CT (NCCT), CT angiography source images (CTASI), and follow-up image by 3-reader consensus. We calculated sensitivity for ischemic changes and analyzed the predictivity of pc-ASPECTS for independent (modified Rankin Scale [mRS] score Յ2) and favorable (mRS score Յ3) outcome. Results-Of 130 patients with suspected vertebrobasilar ischemia, 72% (94) had posterior circulation stroke, 8% (10) transient ischemic attack, and 20% (26)

The quantification of intracranial thrombus extent with the clot burden score predicts functional outcome, final infarct size and parenchymal hematoma risk acutely. The score needs external validation and could be useful for patient stratification in stroke trials.

The introduction of brain imaging with computed tomography revolutionised the treatment of patients with acute ischaemic stroke. With the visual differentiation of haemorrhagic stroke from ischaemic stroke, thrombolytic therapy became feasible. The Alberta Stroke Program Early CT Score was devised to quantify the extent of early ischaemic changes in the middle cerebral artery territory on noncontrast computed tomography. With its systematic approach, the score is simple and reliable. However, the assessment of early ischaemic changes and Alberta Stroke Program Early CT scoring require training. The Alberta Stroke Program Early CT Score is a strong predictor of functional outcome. Furthermore, the effectiveness of intraarterial thrombolysis in patients with middle cerebral artery occlusion shows effect modification by the Alberta Stroke Program Early CT Score. This review summarises the Alberta Stroke Program Early CT Score methodology. We illustrate current knowledge regarding Alberta Stroke Program Early CT Score applied to clinical trials and comment on how Alberta Stroke Program Early CT Score may facilitate clinical treatment decision making and future trial design. Moreover, we introduce a modification of the Alberta Stroke Program Early CT Score methodology that disregards isolated cortical swelling, i.e. focal brain swelling without associated parenchymal hypoattenuation, as early ischaemic changes in the Alberta Stroke Program Early CT Score system.

Background and Purpose-The significance of early ischemic changes (EICs) on computed tomography (CT) to triage patients for thrombolysis has been controversial. The Alberta Stroke Program Early CT Score (ASPECTS) semiquantitatively assesses EICs within the middle cerebral artery territory using a10-point grading system. We hypothesized that dichotomized ASPECTS predicts response to intravenous thrombolysis and incidence of secondary hemorrhage within 6 hours of stroke onset. Methods-Data from the European-Australian Acute Stroke Study (ECASS) II study were used in which 800 patients were randomized to recombinant tissue plasminogen activator (rt-PA) or placebo within 6 hours of symptom onset. We retrospectively assessed all baseline CT scans, dichotomized ASPECTS at Յ7 and Ͼ7, defined favorable outcome as modified Rankin Scale score 0 to 2 after 90 days, and secondary hemorrhage as parenchymal hematoma 1 (PH1) or PH2. We performed a multivariable logistic regression analysis and assessed for an interaction between rt-PA treatment and baseline ASPECTS score. Results-We scored ASPECTS Ͼ7 in 557 and Յ7 in 231 patients. There was no treatment-by-ASPECTS interaction with dichotomized ASPECTS (Pϭ0.3). This also applied for the 0-to 3-hour and 3-to 6-hour cohorts. However, a treatment-by-ASPECTS effect modification was seen in predicting PH (0.043 for the interaction term), indicating a much higher likelihood of thrombolytic-related parenchymal hemorrhage in those with ASPECTS Յ7. Conclusion-In

Background and Purpose-Minimal research has evaluated the renal safety of emergent computed tomography angiography (CTA) procedures, consecutive contrast medium application, and the long-term outcome in acute stroke patients. We investigated the incidence of contrast-induced renal impairment in these populations. Methods-We retrospectively reviewed patients with acute stroke syndrome who received a CTA of the brain with or without the neck within 24 hours from onset of symptoms. All creatinine results and additional conventional angiography findings were recorded. With a positive history of renal disease, contrast administration was delayed until creatinine results were available. Radiocontrast nephropathy (RCN) was defined as a Ն25% increase in serum creatinine from the baseline value up to 5 days after CTA. Results-Four hundred eighty-one patients were reviewed, and 224 met the inclusion criteria. There were 7 of 224 (3%) who fulfilled the criteria for RCN. A number of patients underwent emergent CTA without knowledge of their creatinine value; 2 of 93 (2%) developed RCN. There were 36 patients who received an additional digital subtraction angiogram, and none of these developed subsequent RCN. No patients required dialysis, and 9 of 68 (13%) had a Ͼ25% increase in their creatinine levels at a late (Ͼ30 days) follow-up. Conclusions-Overall, these results illustrate that there is a low incidence of RCN in acute stroke patients undergoing emergency CTA. Key Words: CT angiography Ⅲ digital subtraction angiography Ⅲ radiocontrast nephropathy Ⅲ renal impairment C omputed tomography (CT) bolus techniques have the advantage of minimizing treatment delays but require the use of a nonionic contrast agent. One apprehension surrounding these techniques is the concern of causing radiocontrast nephropathy (RCN). RCN is defined as an increase in the serum creatinine value by Ͼ25% occurring within 3 days after the administration of contrast medium. 1 First, the time from stroke onset to thrombolysis treatment is strongly associated with subsequent outcome in acute stroke. 2 In acute stroke when time is critical, treatment delay due to waiting for a creatinine result is not desirable. 3 Only 1 study has examined the rate of RCN in patients with unknown baseline creatinine levels. 4 Second, it is known that the risk for RCN is proportional to the dose of radiocontrast medium administered. [5][6][7] It has been suggested that multiple, consecutive procedures requiring the use of contrast medium application implies a greater risk for RCN. 8 There have been no large studies examining the safety of consecutive contrast media application in acute stroke for CT angiography (CTA) and digital subtraction angiography (DSA).Third, the long-term outcome in patients undergoing radiocontrast application is unknown. Although serum creatinine levels may return to baseline shortly after receiving contrast medium, some patients may encounter permanent renal sequelae requiring additional medical care. 9 This study sought to determine the freque...

on behalf of the CASES InvestigatorsBackground and Purpose-There is ongoing controversy about the impact of hemorrhagic transformation after thrombolysis on long-term functional outcome. We sought to study the relation between the type of hemorrhagic transformation on CT scans and functional outcome. Methods-Data were obtained from the Canadian Alteplase for Stroke Effectiveness Study. This study was established as a registry to prospectively collect data for acute stroke patients receiving intravenous alteplase within 3 hours from stroke onset between February 1999 and June 2001. Follow-up was completed at 90 days, and good functional outcome was defined as a modified Rankin Scale score of 0 or 1. Copies of head CT scans obtained at 24 to 48 hours after starting treatment were read in consensus by a central reading panel consisting of 1 neuroradiologist and 1 stroke neurologist. According to European Cooperative Acute Stroke Study criteria, hemorrhagic transformation was classified as none, hemorrhagic infarction (HI-1 and HI-2), or parenchymal hematoma (PH-1 and PH-2). We compared outcome across groups and performed a multivariable analysis including previously determined important predictors of good outcome in acute ischemic stroke. Results-From 1135 patients enrolled at 60 centers across Canada, 954 follow-up CT scans were assessable. We observed some hemorrhagic transformation in 259 of 954 (27.1%) patients (110 HI-1, 57 HI-2, 48 PH-1, and 44 PH-2). Proportions of patients with good outcome were 41% with no hemorrhagic transformation, 30% with HI-1, 17% with HI-2, 15% with PH-1, and 7% with PH-2 (PϽ0.0001, 2 test). After adjustment for age, baseline serum glucose, baseline Alberta Stroke Program Early CT score, and baseline National Institutes of Health Stroke Scale score, HI-1 was not a predictor of outcome. However, HI-2 (odds ratioϭ0.38, 95% CIϭ0.17 to 0.83), PH-1 (odds ratioϭ0.32, 95% CIϭ0.12 to 0.80), and PH-2 (odds ratioϭ0.14, 95% CIϭ0.04 to 0.48) were all negative predictors of outcome. Conclusions-The likelihood of a poor outcome after thrombolysis was proportional to the extent of hemorrhage on CT scans. HI grades of hemorrhagic transformation may not be benign. (Stroke. 2007;38:75-79.)

After MCA occlusion, immediate brain tissue net water uptake is associated with a decrease in x-ray attenuation. CT can monitor ischemic edema in an acute stroke.