Validity and reliability of a quantitative computed tomography score in predicting outcome of hyperacute stroke before thrombolytic therapy. ASPECTS Study Group. Alberta Stroke Programme Early CT Score

The extent of perfusion deficit does not relate to the visibility of acute ischemic lesions on fluid-attenuated inversion recovery imaging

OBJECTIVES

Fluid-attenuated inversion recovery imaging (FLAIR) has been suggested as a surrogate marker of lesion age in acute ischemic stroke. In a subgroup analysis, we evaluated whether the extent of perfusion deficit influences FLAIR lesion visibility and thus plays a role as a confounding variable in the interpretation of FLAIR images.

METHODS

A subgroup of patients from a previous study evaluating the use of FLAIR imaging as a surrogate marker of lesion age within the first 6 hours of ischemic stroke were examined to determine the influence of the amount of perfusion deficit on FLAIR lesion visibility.

RESULTS

N = 48 patients were included into the analysis. In positive and negative FLAIR lesion cases the extent of perfusion deficits did not differ significantly (150 mL vs. 197 mL, P = .730) nor influenced FLAIR visibility independently. In contrast, diffusion weighted imaging (DWI) lesion volumes were larger (34 mL vs. 14 mL, P = .008) and time from symptom onset longer (180 vs. 120 minute, P = .071) in FLAIR-positive cases.

CONCLUSION

Visibility of FLAIR lesions in acute stroke imaging is influenced by lesion size and time from symptom onset to MRI, but not by the amount of perfusion deficit calculated by time-to-peak (TTP) measurements.

The prognosis for aphasia in stroke

BACKGROUND

Aphasia is a disabling chronic stroke symptom, but the prognosis for patients presenting with aphasia in the hyperacute window has not been well characterized. The purpose of this study is to assess the prognosis for recovery of language function in subjects presenting with aphasia caused by ischemic stroke within 12 hours of symptom onset.

METHODS

Subjects presenting with aphasia were identified from a prospective cohort study of 669 subjects presenting emergently with acute stroke. Subjects were characterized by demographics, serial clinical examinations, unenhanced computed tomography, and computed tomographic angiography. Aphasia severity was assessed by National Institutes of Health Stroke Scale (NIHSS) examinations performed at baseline, discharge, and 6 months. Demographic, clinical, and imaging factors were assessed for prognostic impact.

RESULTS

Aphasia was present in 30% of subjects (n = 204). Of the 166 aphasic patients alive at discharge (median 5 days), aphasia improved in 57% and resolved in 38%. In the 102 aphasic subjects evaluated at 6 months, aphasia improved in 86% and completely resolved in 74% of subjects. Among aphasic subjects with "mild" stroke (initial NIHSS <5), aphasia resolved in 90% of subjects by 6 months. Factors significantly associated with better outcome included clinically and radiographically smaller strokes and lower prestroke disability.

CONCLUSIONS

The prognosis for full recovery of aphasia present in the hyperacute window is good. Radiographic and clinical markers indicating lesser extent of ischemia correlated to greater recovery. Given the excellent prognosis for language recovery in mild stroke, the net benefit of thrombolysis in such cases is uncertain.

Predicting stroke evolution: comparison of susceptibility-weighted MR imaging with MR perfusion

OBJECTIVES

To investigate the ability of susceptibility-weighted imaging (SWI) to predict stroke evolution in comparison with perfusion-weighted imaging (PWI).

METHODS

In a retrospective analysis of 15 patients with non-lacunar ischaemic stroke studied no later than 24 h after symptom onset, we used the Alberta Stroke Program Early CT Score (ASPECTS) to compare lesions on initial diffusion-weighted images (DWI), SWI, PWI and follow-up studies obtained at least 5 days after symptom onset. The National Institutes of Health Stroke Scale scores at entry and stroke risk factors were documented. The clinical-DWI, SWI-DWI and PWI-DWI mismatches were calculated.

RESULTS

SWI-DWI and mean transit time (MTT)-DWI mismatches were significantly associated with higher incidence of infarct growth (P = 0.007 and 0.028) and had similar ability to predict stroke evolution (P = 1.0). ASPECTS values on initial DWI, SWI and PWI were significantly correlated with those on follow-up studies (P ≤ 0.026) but not associated with infarct growth. The SWI ASPECTS values were best correlated with MTT ones (ρ = 0.8, P < 0.001).

CONCLUSIONS

SWI is an alternative to PWI to assess penumbra and predict stroke evolution. Further prospective studies are needed to evaluate the role of SWI in guiding thrombolytic therapy. Key Points • SWI can provide perfusion information comparable to MTT • SWI-DWI mismatch can indicate ischaemic penumbra • SWI-DWI mismatch can be a predictor for stroke evolution.

The benefits and harms of intravenous thrombolysis with recombinant tissue plasminogen activator within 6 h of acute ischaemic stroke (the third international stroke trial [IST-3]): a randomised controlled trial

BACKGROUND

Thrombolysis is of net benefit in patients with acute ischaemic stroke, who are younger than 80 years of age and are treated within 4·5 h of onset. The third International Stroke Trial (IST-3) sought to determine whether a wider range of patients might benefit up to 6 h from stroke onset.

METHODS

In this international, multicentre, randomised, open-treatment trial, patients were allocated to 0·9 mg/kg intravenous recombinant tissue plasminogen activator (rt-PA) or to control. The primary analysis was of the proportion of patients alive and independent, as defined by an Oxford Handicap Score (OHS) of 0-2 at 6 months. The study is registered, ISRCTN25765518.

FINDINGS

3035 patients were enrolled by 156 hospitals in 12 countries. All of these patients were included in the analyses (1515 in the rt-PA group vs 1520 in the control group), of whom 1617 (53%) were older than 80 years of age. At 6 months, 554 (37%) patients in the rt-PA group versus 534 (35%) in the control group were alive and independent (OHS 0-2; adjusted odds ratio [OR] 1·13, 95% CI 0·95-1·35, p=0·181; a non-significant absolute increase of 14/1000, 95% CI -20 to 48). An ordinal analysis showed a significant shift in OHS scores; common OR 1·27 (95% CI 1·10-1·47, p=0·001). Fatal or non-fatal symptomatic intracranial haemorrhage within 7 days occurred in 104 (7%) patients in the rt-PA group versus 16 (1%) in the control group (adjusted OR 6·94, 95% CI 4·07-11·8; absolute excess 58/1000, 95% CI 44-72). More deaths occurred within 7 days in the rt-PA group (163 [11%]) than in the control group (107 [7%], adjusted OR 1·60, 95% CI 1·22-2·08, p=0·001; absolute increase 37/1000, 95% CI 17-57), but between 7 days and 6 months there were fewer deaths in the rt-PA group than in the control group, so that by 6 months, similar numbers, in total, had died (408 [27%] in the rt-PA group vs 407 [27%] in the control group).

INTERPRETATION

For the types of patient recruited in IST-3, despite the early hazards, thrombolysis within 6 h improved functional outcome. Benefit did not seem to be diminished in elderly patients.

FUNDING

UK Medical Research Council, Health Foundation UK, Stroke Association UK, Research Council of Norway, Arbetsmarknadens Partners Forsakringsbolag (AFA) Insurances Sweden, Swedish Heart Lung Fund, The Foundation of Marianne and Marcus Wallenberg, Polish Ministry of Science and Education, the Australian Heart Foundation, Australian National Health and Medical Research Council (NHMRC), Swiss National Research Foundation, Swiss Heart Foundation, Assessorato alla Sanita, Regione dell'Umbria, Italy, and Danube University.

Factors influencing clinically meaningful recanalization after IV-rtPA in acute ischemic stroke

BACKGROUND AND PURPOSE

Recanalization may not result in better clinical outcomes after ischemic stroke. We determined the incidence and significant predictors of CMR, defined as CT angiographic recanalization and a good clinical outcome, after IV-rtPA in acute ischemic stroke. A CMR score was devised and tested.

MATERIALS AND METHODS

One hundred twenty-six consecutive patients with anterior circulation ischemic stroke receiving IV-rtPA were retrospectively reviewed. Imaging included a baseline NCCT and CTA. Recanalization was assessed on a 24-hour CTA. Clinical outcome was determined by the 90-day mRS. CMR was defined as CTA recanalization and a good clinical outcome (mRS ≤2). Logistic regression analysis determined predictors of CMR. The predictive ability of a CMR score was tested with AIC.

RESULTS

CMR occurred in 29% (36/126). Patients with CMR had fewer neurologic deficits (P = .001) and higher ASPECTS (P = .041) at baseline than those without CMR. Baseline NIHSS score did not predict proximal occlusion (OR 0.959; 95% CI [0.907-1.014]; P = .141). Multivariate analysis showed admission NIHSS score (P = .001) and the site of vessel occlusion (P = .022) to be significant CMR predictors. CMR was significantly less likely in patients with proximal occlusions (ICA, P = .005; proximal M1, P = .021). A CMR score better predicted CMR than either NIHSS or vessel occlusion site alone (P < .0001).

CONCLUSIONS

Milder baseline stroke deficit and distal vessel occlusion are significant predictors of CMR. A combination of these parameters better predicts CMR than either parameter alone.

Diffuse Ischemia in Noncontrast Computed Tomography Predicts Outcome in Patients in Intensive Care Unit

Purpose

In the intensive care unit (ICU), prognosticating patients who are comatose or defining brain death can be challenging. Currently, the criteria for brain death are clinical supported by paraclinical tests. Noncontrast computed tomography (CT) shows diffuse loss of grey-white differentiation consistent with infarction. We hypothesize that the extent of hypodensity is predictive of poor neurologic outcome or brain death.

Materials and Methods

A total of 235 consecutive adult patients with cardiac arrest or with serious trauma admitted to ICU in 1 year were studied. Seventy met inclusion criteria. CT images were reviewed by multiple observers blinded to final outcome who assessed for loss of grey-white conspicuity. A modification of the validated Alberta Stroke Program Early CT Score (ASPECTS) was used to include non–middle cerebral artery territories. Primary outcome was death or functional disability at 3 months. Dichotomized CT scores were correlated with poor clinical status (Glasgow Coma Score < 5 and APACHE [Acute Physiology and Chronic Health Evaluation] score >19) and poor outcome (modified Rankin Scale >2).

Results

The CT score was ≤10 in 7 patients and >10 in 63 patients. The CT score value correlated with the severity of baseline clinical status on the Glasgow Coma Score ( r = 0.53, P < .01) and negatively with the APACHE-II score ( r = −0.27, P < .05). The CT score value negatively correlated with functional outcome ( r = −0.40, P < .01). All the patients with a CT score ≤10 died. The sensitivity of the CT score for functional outcome was 24%, and specificity was 100%. Agreement among observers for the CT score was good (Intraclass correlation coefficient = 0.77).

Conclusion

Diffuse loss of grey-white matter differentiation is subtle but specific for poor neurologic outcome, which may allow earlier prognostication of patients in whom clinical parameters are difficult to assess.

Beyond the time window of intravenous thrombolysis: standing by or by stenting?

Intravenous administration of tissue plasminogen activator within 4.5 h of symptom onset is presently the 'golden rule' for treating acute ischemic stroke. However, many patients miss the time window and others reject this treatment due to a long list of contraindications. Mechanical embolectomy has recently progressed as a potential alternative for treating patients beyond the time window for IV thrombolysis. In this paper, recent progress in mechanical embolectomy, angioplasty, and stenting in acute stroke is reviewed. Despite worries concerning the long-term clinical outcomes and increased risk of intracranial hemorrhage, favorable clinical outcomes may be achieved after mechanical embolectomy in carefully selected patients even 4.5 h after stroke onset. Potential steps should be prepared and attempted in these patients whose opportunity for recovery will elapse in a flash.

Risk assessment of hemorrhagic transformation of acute middle cerebral artery stroke using multimodal CT

PURPOSE

Multimodal CT with CT angiography (CTA) and CT perfusion (CTP) are increasingly used in stroke triage. Our aim was to identify parameters most predictive of hemorrhagic transformation (HT), especially symptomatic intracerebral hemorrhage (SICH).

METHODS

This retrospective study included patients evaluated by baseline multimodal CT ≤ 9 hours from ictus with acute nonlacunar middle cerebral artery (MCA) territory infarction. Two readers independently evaluated CTP maps for ischemic severity and CTA source images (CTA-SI) for infarct extent (as measured by ASPECTS). Presence of proximal occlusion (ICA or M1) and degree of collateralization (collateral score) were also assessed on CTA. HT was defined as SICH if associated with deterioration ≥ 4-points on NIHSS. Multivariate logistic regression analysis identified independent predictors of SICH. ROC curves selected optimal thresholds.

RESULTS

Of 84 patients reviewed, HT occurred in 22 (26.2%) and SICH in 8 (9.5%). Univariate predictors for SICH were proximal occlusion (OR = 8.65, P= .049), collateral score (OR = .34, P= .017), ASPECTS (OR = .46, P= .001), and CBV (OR = .001, P= .005). Multivariate analysis revealed ASPECTS as the only independent predictor with optimal threshold ≤ 5 and sensitivity and specificity of 75.0% and 85.5%, respectively.

CONCLUSION

For acute MCA infarcts ≤ 9 hours, the strongest predictor of SICH on multimodal CT was ASPECTS on CTA-SI.

Endovascular treatment strategies for acute ischemic stroke

The limitations of intravenous thrombolysis therapy have paved the way for the development of novel endovascular technologies for use in the setting of acute stroke. These technologies range from direct intraarterial thrombolysis to various thrombus disruption or retrieval devices to angioplasty and stenting. The tools in the armamentarium of the neuroendovascular interventionalist enable fast, effective revascularization to be offered to a wider population of patients that may otherwise have few therapeutic options available to them. In this paper, we review the current state-of-the-art in neuroendovascular intervention for acute ischemic stroke. Particular emphasis is placed on delineating the indications and outcomes for use of these various technologies.

CT perfusion imaging in acute stroke

Computed tomographic perfusion (CTP) imaging is an advanced modality that provides important information about capillary-level hemodynamics of the brain parenchyma. CTP can aid in diagnosis, management, and prognosis of acute stroke patients by clarifying acute cerebral physiology and hemodynamic status, including distinguishing severely hypoperfused but potentially salvageable tissue from both tissue likely to be irreversibly infarcted ("core") and hypoperfused but metabolically stable tissue ("benign oligemia"). A qualitative estimate of the presence and degree of ischemia is typically required for guiding clinical management. Radiation dose issues with CTP imaging, a topic of much current concern, are also addressed in this review.

ASPECTS and other neuroimaging scores in the triage and prediction of outcome in acute stroke patients

Information obtained from brain imaging is now summarized in the form of various neuroimaging scores to help physicians in making therapeutic decisions and determining prognosis. The Alberta Stroke Program Early CT Score (ASPECTS) was devised to quantify the extent of early ischemic changes in the middle cerebral artery territory on noncontrast computed tomography. With its systematic approach, the score is simple, reliable, and a strong predictor of functional outcome. This review summarizes ASPECTS and other neuroimaging scores developed for risk prognostication and risk stratification with treatment in patients with acute ischemic stroke.

Modified ASPECTS for DWI including deep white matter lesions predicts subsequent intracranial hemorrhage

We hypothesized that extensive early ischemic changes increase subsequent intracranial hemorrhage (ICH) in patients within 3 h of onset regardless of intravenous tPA (IV-tPA). We have established a modified scoring method, ASPECTS+W, including deep white matter lesions on DWI (DWI-W) in addition to the original ASPECTS regions. We aimed to elucidate whether CT-ASPECTS, DWI-ASPECTS, and ASPECTS+W could be useful tools in helping to predict subsequent ICH in acute ischemic stroke. One-hundred sixty-four consecutive patients with anterior circulation ischemic stroke were enrolled. All patients underwent both MRI and CT within 3 h of onset. ASPECTS+W was defined as an 11-point method combining the ten ASPECTS regions and DWI-W. The relationships of CT-ASPECTS, DWI-ASPECTS, and ASPECTS+W with ICH within the initial 36 h were assessed. Thirty-six patients (22%) were treated with IV-tPA. Follow-up CT was obtained in 159 patients, and 19 (12%) developed ICH. Patients with ICH had higher baseline NIHSS scores (median, 25 vs. 13, p = 0.010), a higher rate of IV-tPA (42 vs. 20%, p = 0.041), lower CT-ASPECTS (median, 7 vs. 10, p = 0.008), lower DWI-ASPECTS (6 vs. 9, p = 0.001), lower ASPECTS+W (6 vs. 9, p = 0.001), and higher DWI-W lesions (74 vs. 47%, p = 0.048) than those without ICH. ICA or M1 proximal occlusion was more frequently seen in patients with ICH (68 vs. 32%, p = 0.004) than in those without ICH. On multivariate regression analysis, lower ASPECTS+W (OR 0.75, 95% CI 0.58–0.96, p = 0.027) and administration of IV-tPA (OR 9.13, 95% CI 2.15–46.21, p = 0.004) independently predicted ICH development. In conclusion, ASPECTS+W is a useful tool for predicting ICH development independent of IV-tPA.

Interobserver reliability of baseline noncontrast CT Alberta Stroke Program Early CT Score for intra-arterial stroke treatment selection

BACKGROUND AND PURPOSE

Early ischemic changes on pretreatment NCCT quantified using ASPECTS have been demonstrated to predict outcomes after IAT. We sought to determine the interobserver reliability of ASPECTS for patients with AIS with PAO and to determine whether pretreatment ASPECTS dichotomized at 7 would demonstrate at least substantial κ agreement.

MATERIALS AND METHODS

From our prospective IAT data base, we identified consecutive patients with anterior circulation PAO who underwent IAT over a 6-year period. Only those with an evaluable pretreatment NCCT were included. ASPECTS was graded independently by 2 experienced readers. Interrater agreement was assessed for total ASPECTS, dichotomized ASPECTS (≤ 7 versus >7), and each ASPECTS region. Statistical analysis included determination of Cohen κ coefficients and concordance correlation coefficients. PABAK coefficients were also calculated.

RESULTS

One hundred fifty-five patients met our study criteria. Median pretreatment ASPECTS was 8 (interquartile range 7-9). Interrater agreement for total ASPECTS was substantial (concordance correlation coefficient = 0.77). The mean ASPECTS difference between readers was 0.2 (95% confidence interval, -2.8 to 2.4). For dichotomized ASPECTS, there was a 76.8% (119/155) observed rate of agreement, with a moderate κ = 0.53 (PABAK = 0.54). By region, agreement was worst in the internal capsule and the cortical areas, ranging from fair to moderate. After adjusting for prevalence and bias, agreement improved to substantial or near perfect in most regions.

CONCLUSIONS

Interobserver reliability is substantial for total ASPECTS but is only moderate for ASPECTS dichotomized at 7. This may limit the utility of dichotomized ASPECTS for IAT selection.

Curitiba acute ischemic stroke protocol: a university hospital and EMS initiative in a large Brazilian city

Few healthcare centers in Brazil perform thrombolytic therapy for acute ischemic stroke (AIS) patients.

OBJECTIVE

The aim of this study was to describe an interinstitutional protocol for the rapid identification and thrombolytic treatment of AIS patients at a public health hospital in a large Brazilian city.

METHOD

Emergency medical services (EMS) personnel evaluated 433 patients with possible stroke during a six-month period. After a standard checklist, patients with suspected AIS and symptoms onset of less than two hours were evaluated at our University Hospital (UH).

RESULTS

Sixty-five (15%) patients met the checklist criteria and had a symptom onset of less than two hours, but only 50 (11%) patients were evaluated at the UH. Among them, 35 (70%) patients had ischemic stroke, 10 (20%) had hemorrhagic stroke, and 5 (10%) had other diagnoses. Of the 35 ischemic stroke patients, 15 (43%) underwent IV thrombolysis.

CONCLUSION

The present study demonstrated that trained EMS workers could help to improve the rate of thrombolytic treatment in large Brazilian cities. Permanent training programs for EMS and hospital staff, with quality control and correct identification of AIS patients, should be implemented to increase appropriate thrombolytic therapy rates in Brazil.

Improved outcome prediction using CT angiography in addition to standard ischemic stroke assessment: results from the STOPStroke study

PURPOSE

To improve ischemic stroke outcome prediction using imaging information from a prospective cohort who received admission CT angiography (CTA).

METHODS

In a prospectively designed study, 649 stroke patients diagnosed with acute ischemic stroke had admission NIH stroke scale scores, noncontrast CT (NCCT), CTA, and 6-month outcome assessed using the modified Rankin scale (mRS) scores. Poor outcome was defined as mRS>2. Strokes were classified as "major" by the (1) Alberta Stroke Program Early CT Score (ASPECTS+) if NCCT ASPECTS was ≤7; (2) Boston Acute Stroke Imaging Scale (BASIS+) if they were ASPECTS+ or CTA showed occlusion of the distal internal carotid, proximal middle cerebral, or basilar arteries; and (3) NIHSS for scores >10.

RESULTS

Of 649 patients, 253 (39.0%) had poor outcomes. NIHSS, BASIS, and age, but not ASPECTS, were independent predictors of outcome. BASIS and NIHSS had similar sensitivities, both superior to ASPECTS (p<0.0001). Combining NIHSS with BASIS was highly predictive: 77.6% (114/147) classified as NIHSS>10/BASIS+ had poor outcomes, versus 21.5% (77/358) with NIHSS≤10/BASIS- (p<0.0001), regardless of treatment. The odds ratios for poor outcome is 12.6 (95% CI: 7.9 to 20.0) in patients who are NIHSS>10/BASIS+ compared to patients who are NIHSS≤10/BASIS-; the odds ratio is 5.4 (95% CI: 3.5 to 8.5) when compared to patients who are only NIHSS>10 or BASIS+.

CONCLUSIONS

BASIS and NIHSS are independent outcome predictors. Their combination is stronger than either instrument alone in predicting outcomes. The findings suggest that CTA is a significant clinical tool in routine acute stroke assessment.

Prediction of intracerebral hemorrhage following thrombolytic therapy for acute ischemic stroke using multiple artificial neural networks

OBJECTIVES

Artificial neural networks (ANNs) have been increasingly used in diagnosis and the prediction of outcome, mortality, and risk factors in ischemic stroke. Each model may have different accuracy, sensitivity, and specificity in processing the same clinical information. Thus, using only one model of ANNs may mislead the prediction. The present study aimed to predict symptomatic intracerebral hemorrhage (SICH) following thrombolysis in acute ischemic stroke based on clinical, laboratory, and imaging data using multiple ANN models.

METHODS

Models for radial basis function (RBF), multilayer perceptron (MLP), probabilistic neural network (PNN), and support vector machine (SVM) were generated to analyze 194 datasets with 29 predictive variables. The relative importance of each predictor variable was calculated using sensitivity analysis.

RESULTS

Comparison among the models based on the areas under the receiver operating characteristic curves (AUC) showed no significantly statistical difference in predictive performance among RBF, MLP, and PNN. PNN showed significantly better performance than SVM. With a minimum importance score of 50 together with an AUC value ≥0·50, three models identified stroke subtype as an important predictive variable for SICH. Other potential predictors were stroke location, prothrombin time, low-density-lipoprotein cholesterol, diastolic blood pressure, International Normalized Ratio, and brain computed tomography findings.

DISCUSSION

Although ANN models showed similar performance, the classification results were not totally alike, suggesting an advantage of using multiple classification models over a single model. The predictive results are supported by previous statistical studies on different datasets, suggesting generalizability of the utility of ANN analyses.

Early findings on brain computed tomography and the prognosis of post-cardiac arrest syndrome: application of the score for stroke patients

AIM

To examine whether early findings of the brain computed tomography (CT) evaluated by the modified Alberta stroke programme early CT (m-ASPECT) score is useful for determining the prognosis of post-cardiac arrest syndrome (PCAS) patients or not.

MATERIALS

From 2003 through 2010, 149 consecutive PCAS patients: (1) with various aetiologies but neither from haemorrhagic stroke nor trauma, (2) who were 15 years old or older and (3) whose brain CT was available were admitted to our intensive care unit. Early findings on all of their CT images were rated with the m-ASPECT scoring system by three raters, and an inter-rater comparison was conducted. Next, the images within 24 h from arrest were collected from 133 patients (89 males, age 60.2±17.6 years), and a relation of the scores with outcome at day 30 of the patients was analysed.

RESULTS

According to the inter-rater comparison based on a linear regression analysis, agreement between the raters was good (correlation coefficient 0.76-0.88). A receiver operating curve analysis revealed that the m-ASPECT scores within 24 h were a good predictor of poor outcome (dead or vegetative state) with an area under the curve of 0.905. An m-ASPECT score ≤13 was 100% predictive of a poor outcome, with a negative predictive value of 0.57. The m-ASPECT score was the best predictor of poor outcome (odds ratio 45.62) among various factors including cause or duration of arrest.

CONCLUSION

The m-APSECT score evaluated within 24 h from arrest was found to be the most predictive factor for outcome at day 30.

Arterial blood gas analysis of samples directly obtained beyond cerebral arterial occlusion during endovascular procedures predicts clinical outcome

Real-time intra-procedure information about ischemic brain damage degree may help physicians in taking decisions about pursuing or not recanalization efforts.

METHODS

We studied gasometric parameters of blood samples drawn through microcatheter in 16 stroke patients who received endovascular reperfusion procedures. After crossing the clot with microcatheter, blood sample was obtained from the middle cerebral artery (MCA) segment distal to occlusion (PostOcc); another sample was obtained from carotid artery (PreOcc). An arterial blood gas (ABG) study was immediately performed. We defined clinical improvement as National Institutes of Health Stroke Scale (NIHSS) decrease of ≥4.

RESULTS

The ABG analysis showed differences between PreOcc and PostOcc blood samples in mean oxygen partial pressure (Pre-PaO2: 78.9 ± 16 .3 vs. 73.9 ± 14 .9 mmHg; P < .001). Patients who presented clinical improvement had higher Post-PaO2 (81 ± 11 .4 vs. 64.8 ± 14 .4 mmHg; P = .025). A receiver-operator characteristic (ROC) curve determined Post-PaO2 > 70 mmHg that better predicted further clinical improvement. Patients with Post-PaO2 > 70 mmHg had higher chances of clinical improvement (81.8% vs. 0%; P = .002) and lower disability (median mRS:3 vs. 6; P= .024). In the logistic regression the only independent predictor of clinical improvement was Post-PaO2 > 70 (OR: 5.21 95% CI: 1.38-67.24; P = .013).

CONCLUSION

Direct local blood sampling from ischemic brain is feasible during endovascular procedures in acute stroke patients. A gradient in oxygenation parameters was demonstrated between pre- and post-occlusion blood samples. ABG information may be used to predict clinical outcome and help in decision making in the angio-suite.

Long-term prediction of functional outcome after stroke using the Alberta Stroke Program Early Computed Tomography Score in the subacute stage

Stroke patients who arrive at hospital more than 24 hours after symptom onset could benefit from a simple means of assessing long-term prognosis in this subacute stage. We evaluated whether clinical factors along with ischemic injury assessed subacutely using the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) had predictive value for functional independence after stroke. Computed tomography (CT) scans obtained ≥ 2 days after first-ever ischemic stroke were scored independently and retrospectively by 3 stroke neurologists using the ASPECTS. Functional outcome was measured using the Functional Independence Measure, which assesses the amount of caregiver assistance required by patients during daily activities. Multiple linear regression was used to develop a predictive model for functional prognosis at 1 month, 3 months, and 1 year poststroke. For our 55 patients, CT scanning was done on average 4 days poststroke. The interrater agreement for subacute ASPECTS was excellent, with a κ-weighted value of 0.90. Lesions involving the frontal and superior parietal ASPECTS regions were significant predictors of lower Functional Independence Measure scores at all 3 time points studied. In combination with such factors as age, marital status, and the severity of initial neurologic deficit, a subacute ASPECTS score >5 had significant predictive value for greater functional independence at 3 months (R(2) = 0.701; P < .001) and 1 year (R(2) = 0.528; P < .001) poststroke. Our data indicate that in the subacute stage, ASPECTS is reliable and can help predict which patients may be likely to regain functional independence up to 1 year after sustaining ischemic stroke.

A mobile tele-radiology imaging system with JPEG2000 for an emergency care

The aim of this study was to design a tele-radiology imaging system for rapid emergency care via mobile networks and to assess the diagnostic feasibility of the Joint Photographic Experts Group 2000 (JPEG2000) radiological imaging using portable devices. Rapid patient information and image exchange is helpful to make clinical decisions. We assessed the usefulness of the mobile tele-radiology system by measuring both a quantitative method, PNSR calculation, for image qualities, and its transmission time via mobile networks in different mobile networks, respectively; code division multiple access evolution-data optimized, wireless broadband, and high-speed downlink packet access; and the feasibility of the JPEG2000 computed tomography (CT) images by qualitatively assessing with the Alberta stroke program early CT score method with 12 CT image cases (seven normal and five abnormal cases). We found that the quality of the JPEG2000 radiological images was satisfied quantitatively and was judged as acceptable qualitatively at 5:1 and 10:1 compression levels for the mobile tele-radiology imaging system. The JPEG2000-format radiological images achieved a fast transmission while maintaining a diagnosis quality on a portable device via mobile networks. Unfortunately, a PDA device, having a limited screen resolution, posed difficulties in reviewing the JPEG2000 images regardless of the compression levels. An ultra mobile PC was preferable to study the medical image. The mobile tele-radiology imaging systems supporting JPEG2000 image transmission can be applied to actual emergency care services under mobile computing environments.

Computer-aided detection scheme for identification of hypoattenuation of acute stroke in unenhanced CT

Our purpose in this study was to develop a computer-aided detection scheme for identification of hypoattenuation of acute stroke on unenhanced CT images to select patients for thrombolysis of acute stroke. This method is based on a z-score mapping method. The algorithm of the developed method consisted of five main steps: anatomic standardization, calculation of the z-score with a normal reference database, extraction of candidate voxels for hypoattenuation, feature extraction, and classification. The territory of the middle cerebral artery was divided into ten specified regions, according to a visually quantitative CT scoring system, the Alberta Stroke Programme Early CT Score (ASPECTS) method. Each of the ASPECTS-defined regions was classified as hypoattenuation or normality by linear discriminate analysis. The method was applied to 26 patients who had hypoattenuation areas (<6 h). The performance of this scheme for classification of hypoattenuation was evaluated using a leave-one-case-out method. As a result, an average sensitivity of 89.7% and an average specificity of 85.2% for automatically classifying hypoattenuation regions in the lentiform nucleus and the insular regions were obtained, and the average accuracy for the classification of hypoattenuation per patient was 84.6% (range 55.6-100%). The newly developed method has the potential accurately to identify hypoattenuation of acute stroke in the ASPECTS-defined regions.

Wake-up stroke within 3 hours of symptom awareness: imaging and clinical features compared to standard recombinant tissue plasminogen activator treated stroke

BACKGROUND

Patients with wake-up stroke (WUS) are excluded from thrombolysis because of unknown time of symptom onset. Previous studies have reported similar stroke severity and early ischemic changes (EICs) in patients with WUS and stroke of known onset. These studies, however, included patients within a large timeframe to imaging or did not quantify EICs. The aim of our study was to quantify EICs of patients with WUS presenting within 3 hours of symptom recognition compared to standard 3-hours recombinant tissue plasminogen activator (rt-PA)-treated patients and assess the extent of ischemic lesion and functional independence at follow-up.

METHODS

Patients were selected from our prospectively collected stroke database. Baseline and follow-up computed tomographic scans were graded with Alberta Stroke Program Early Computed Tomography Score (ASPECTS). Clinical outcome measures were modified Rankin Scale score, mortality, and symptomatic intracerebral hemorrhage.

RESULTS

Demographic features, risk factors, stroke severity, and baseline ASPECTS were similar in both groups. WUS and rt-PA-treated patients had similar tissue outcome (median ASPECTS 7.0 vs 7.5; P = .202). Functional outcome was more favorable in rt-PA-treated patients (61.6% vs 43.1%; odds ratio [OR] 2.12; 95% confidence interval [CI] 1.05-4.28; P = .037). After adjusting for age, stroke severity, treatment, and EICs in less than one-third of middle cerebral artery territory, rt-PA and National Institutes of Health Stroke Scale scores remained the only significant predictors of outcome (OR 7.76; 95% CI 2.40-25.05; P = .001 and OR 0.74; 95% CI 0.67-0.82; P < .001, respectively).

CONCLUSIONS

Within 3 hours of symptom recognition, patients with WUS have EICs similar to rt-PA-treated patients. It is reasonable to expect that selected WUS patients might benefit from thrombolysis within 3 hours of symptom awareness.

Sulcal effacement on fluid attenuation inversion recovery magnetic resonance imaging in hyperacute stroke: association with collateral flow and clinical outcomes

BACKGROUND AND PURPOSE

The clinical significance of sulcal effacement has been widely investigated in CT studies, but the results are controversial. In this study, we evaluated the presence of perisylvian sulcal effacement (PSE) on fluid attenuation inversion recovery MRI and hypothesized that PSE may be related to collateral flow status together with hyperintense vessels on fluid attenuation inversion recovery in hyperacute stroke. In addition, we investigated whether an association between PSE and clinical outcome could be found in these patients.

METHODS

Consecutive patients with acute middle cerebral artery infarcts within 6 hours of symptom onset were included. All patients had internal carotid artery or middle cerebral artery occlusion and underwent MRI including FLAIR. The presence of PSE and hyperintense vessels on fluid attenuation inversion recovery and the collateral status and occurrence of early recanalization (ER) on conventional angiography were evaluated.

RESULTS

Of 139 patients, 79 (56.8%) had PSE. Multivariate testing revealed PSE was independently associated with collateral status. The association between hyperintense vessels and collaterals was different depending on PSE. Compared to PSE-positive and ER-negative patients, PSE-negative and ER-negative patients (odds ratio, 4.11; 95% confidence interval, 1.12-15.17) and PSE-negative and ER-positive patients (odds ratio, 34.62; 95% confidence interval, 5.75-208.60), but not PSE-positive and ER-positive patients, were more likely to experience favorable clinical outcomes (modified Rankin Scale score ≤ 2 at 3 months).

CONCLUSIONS

PSE is independently associated with collateral status in patients with acute middle cerebral artery stroke. Moreover, PSE in conjunction with recanalization status can predict clinical outcomes in these patients.

Early ischemic CT changes before thrombolysis: The influence of age and diabetes mellitus

OBJECTIVES

The significance of early ischemic changes (EIC) on computed tomography (CT) within 3 hours after stroke onset remains controversial. The semi-quantitative Alberta Stroke Program Early CT Score (ASPECTS) is found to have prognostic value in early stroke. This study assesses factors associated with the presence of EIC and the relation between EIC and clinical outcome.

MATERIALS AND METHODS

CT scans from 61 consecutive patients receiving thrombolytic therapy were reviewed by 3 experienced stroke neurologists, assessing EIC (ASPECTS) and vascular signs (hyperdense middle cerebral artery stem and/or branches). Short-term outcome was assessed with the National Institute of Health Stroke Scale at 24 hours and long-term outcome with the modified Rankin Scale score after 3 months.

RESULTS

The prevalence of EIC was 54% and the agreement between assessors was good (kappa 0.52-0.67). EIC was independently associated with younger age and absence of diabetes mellitus. Neither EIC nor vascular signs were associated with 3-months outcome.

CONCLUSIONS

ASPECTS is as simple, systematic approach to assessing EIC, and the inter-observer agreement is good. Patient age and diabetes mellitus influence the presence of EIC.

Insulin resistance is associated with a poor response to intravenous thrombolysis in acute ischemic stroke

OBJECTIVE

Insulin resistance (IR) may not only increase stroke risk, but could also contribute to aggravate stroke prognosis. Mainly through a derangement in endogenous fibrinolysis, IR could affect the response to intravenous thrombolysis, currently the only therapy proved to be efficacious for acute ischemic stroke. We hypothesized that high IR is associated with more persistent arterial occlusions and poorer long-term outcome after stroke thrombolysis.

RESEARCH DESIGN AND METHODS

We performed a prospective, observational, longitudinal study in consecutive acute ischemic stroke patients presenting with middle cerebral artery (MCA) occlusion who received intravenous thrombolysis. Patients with acute hyperglycemia (≥155 mg/dL) receiving insulin were excluded. IR was determined during admission by the homeostatic model assessment index (HOMA-IR). Poor long-term outcome, as defined by a day 90 modified Rankin scale score ≥ 3, was considered the primary outcome variable. Transcranial Duplex-assessed resistance to MCA recanalization and symptomatic hemorrhagic transformation were considered secondary end points.

RESULTS

A total of 109 thrombolysed MCA ischemic stroke patients were included (43.1% women, mean age 71 years). The HOMA-IR was higher in the group of patients with poor outcome (P = 0.02). The probability of good outcome decreased gradually with increasing HOMA-IR tertiles (80.6%, 1st tertile; 71.4%, 2nd tertile; and 55.3%, upper tertile). A HOMA-IR in the upper tertile was independently associated with poor outcome when compared with the lower tertile (odds ratio [OR] 8.54 [95% CI 1.67-43.55]; P = 0.01) and was associated with more persistent MCA occlusions (OR 8.2 [1.23-54.44]; P = 0.029).

CONCLUSIONS

High IR may be associated with more persistent arterial occlusions and worse long-term outcome after acute ischemic stroke thrombolysis.

Predictive role of modified clinical diffusion mismatch in early neurological deterioration due to atherothrombotic ischemia in the anterior circulation

BACKGROUND

Atherothrombotic ischemia is the most frequent cause of cerebral ischemia; however, few reports have addressed the prognostic factors predicting early neurological deterioration (END) when the occlusive lesion is limited to the anterior main trunk, middle cerebral artery (MCA) or internal cerebral artery (ICA).

METHOD

Between 2006 and 2008, 122 atherothrombotic ischemia patients were diagnosed with MCA or ICA occlusive disease on magnetic resonance angiography. The National Institutes of Health Stroke Scale (NIHSS) score and the modified Alberta Stroke Program Early CT Score on diffusion-weighted imaging [ASPECTS-DW (modified)] were calculated. Clinical-DWI mismatch (CDM) was evaluated using NIHSS and the ASPECTS-DW (modified) to examine the predictive efficacy for early neurological deterioration.

RESULTS

Eighteen of 122 (14.8%) patients fulfilled the definition of CDM. END was observed in 24 patients (19.7%) within 15 days after admission. CDM was observed in 14 cases in the END (+) group (14 of 24 cases, 58.3%) and 4 cases in the END (-) group (4 of 98 cases, 4.1%) (p = 0.001). Multivariate logistic regression analysis demonstrated that CDM was a significant predictive factor of END (odds ratio 26.68, p = 0.0001).

CONCLUSIONS

CDM based on NIHSS and ASPECTS-DW (modified) could be a significant predictive factor for END of atherothrombotic ischemia in MCA/ICA.

Safety and clinical outcome of thrombolysis in ischaemic stroke using a perfusion CT mismatch between 3 and 6 hours

OBJECTIVE

It may be possible to thrombolyse ischaemic stroke (IS) patients up to 6 h by using penumbral imaging. We investigated whether a perfusion CT (CTP) mismatch can help to select patients for thrombolysis up to 6 h.

METHODS

A cohort of 254 thrombolysed IS patients was studied. 174 (69%) were thrombolysed at 0-3 h by using non-contrast CT (NCCT), and 80 (31%) at 3-6 h (35 at 3-4.5 h and 45 at 4.5-6 h) by using CTP mismatch criteria. Symptomatic intracerebral haemorrhage (SICH), the mortality and the modified Rankin Score (mRS) were assessed at 3 months. Independent determinants of outcome in patients thrombolysed between 3 and 6 h were identified.

RESULTS

The baseline characteristics were comparable in the two groups. There were no differences in SICH (3% v 4%, p = 0.71), any ICH (7% v 9%, p = 0.61), or mortality (16% v 9%, p = 0.15) or mRS 0-2 at 3 months (55% v 54%, p = 0.96) between patients thrombolysed at 0-3 h (NCCT only) or at 3-6 h (CTP mismatch). There were no significant differences in outcome between patients thrombolysed at 3-4.5 h or 4.5-6 h. The NIHSS score was the only independent determinant of a mRS of 0-2 at 3 months (OR 0.89, 95% CI 0.82-0.97, p = 0.007) in patients treated using CTP mismatch criteria beyond 3 h.

CONCLUSIONS

The use of a CTP mismatch model may help to guide thrombolysis decisions up to 6 h after IS onset.

Regional leptomeningeal score on CT angiography predicts clinical and imaging outcomes in patients with acute anterior circulation occlusions

BACKGROUND AND PURPOSE

The regional leptomeningeal score is a strong and reliable imaging predictor of good clinical outcomes in acute anterior circulation ischemic strokes and can therefore be used for imaging based patient selection. Efforts to determine biological determinants of collateral status are needed if techniques to alter collateral behavior and extend time windows are to succeed.

MATERIALS AND METHODS

This was a retrospective Institutional Review Board-approved study of patients with acute ischemic stroke and M1 middle cerebral artery+/- intracranial internal carotid artery occlusion at our center from 2003 to 2009. The rLMC score is based on scoring pial and lenticulostriate arteries (0, no; 1, less; 2, equal or more prominent compared with matching region in opposite hemisphere) in 6 ASPECTS regions (M1-6) plus anterior cerebral artery region and basal ganglia. Pial arteries in the Sylvian sulcus are scored 0, 2, or 4. Good clinical outcome was defined as mRS ≤ 2 at 90 days.

RESULTS

The analysis included 138 patients: 37.6% had a good (17-20), 40.5% a medium (11-16), and 21.7% a poor (0-10) rLMC score. Interrater reliability was high, with an intraclass correlation coefficient of 0.87 (95% CI, 0.77%-0.95%). On univariate analysis, no single vascular risk factor was associated with the presence of poor rLMCs (P ≥ .20 for all comparisons). In multivariable analysis, the rLMC score (good versus poor: OR, 16.7; 95% CI, 2.9%-97.4%; medium versus poor: OR, 9.2, 95% CI, 1.7%-50.6%), age (< 80 years), baseline ASPECTS (≥ 8), and clot burden score (≥ 8) were independent predictors of good clinical outcome.

CONCLUSIONS

The rLMC score is a strong imaging parameter on CT angiography for predicting clinical outcomes in patients with acute ischemic strokes.

The role of imaging studies for evaluation of stroke in children

Stroke is a major cause of morbidity and mortality in children and long-term neurological deficits. Although cerebrovascular disorders occur less often in children than in adults, recognition of stroke in children has probably increased because of the widespread application of noninvasive diagnostic studies such as magnetic resonance imaging and computed tomography.Computed tomography (CT) should be the first imaging choice in the emergency setting when stroke is suspected. It will show the presence of hemorrhage (eg, bleeding from arteriovenous malformation). It is often normal within the first hours in arterial ischemic stroke. As in adults, magnetic resonance imaging is the neuroimaging modality to confirm the clinical diagnosis of ischemic stroke. In children, however, magnetic resonance imaging requires sedation and may not be as readily available as CT. Perfusion imaging demonstrates flow within the brain and can detect areas that are at risk of ischemia; however, further studies in the pediatric population need to be validated for this technique in children. Angiography detects arterial disease (eg, aneurysm); however, its use has been largely superseded by better magnetic resonance angiography, which is sensitive enough to visualize lesions in the proximal anterior cerebral artery, middle cerebral artery, and distal internal carotid artery (ICA). Magnetic resonance imaging using diffusion- weighted imaging is the most versatile and sensitive imaging technique for identifying ischemic lesions. In the future, we need to identify the pediatric patient presenting to the emergency department with an acute stroke and develop a pathway for the use of particular imaging techniques (eg, CT vs magnetic resonance imaging).

Extending the time window for endovascular procedures according to collateral pial circulation

BACKGROUND AND PURPOSE

Good collateral pial circulation (CPC) predicts a favorable outcome in patients undergoing intra-arterial procedures. We aimed to determine if CPC status may be used to decide about pursuing recanalization efforts.

METHODS

Pial collateral score (0-5) was determined on initial angiogram. We considered good CPC when pial collateral score<3, defined total time of ischemia (TTI) as onset-to-recanalization time, and clinical improvement>4-point decline in admission-discharge National Institutes of Health Stroke Scale.

RESULTS

We studied CPC in 61 patients (31 middle cerebral artery, 30 internal carotid artery). Good CPC patients (n=21 [34%]) had lower discharge National Institutes of Health Stroke Scale score (7 versus 21; P=0.02) and smaller infarcts (56 mL versus 238 mL; P<0.001). In poor CPC patients, a receiver operating characteristic curve defined a TTI cutoff point<300 minutes (sensitivity 67%, specificity 75%) that better predicted clinical improvement (TTI<300: 66.7% versus TTI>300: 25%; P=0.05). For good CPC patients, no temporal cutoff point could be defined. Although clinical improvement was similar for patients recanalizing within 300 minutes (poor CPC: 60% versus good CPC: 85.7%; P=0.35), the likelihood of clinical improvement was 3-fold higher after 300 minutes only in good CPC patients (23.1% versus 90.1%; P=0.01). Similarly, infarct volume was reduced 7-fold in good as compared with poor CPC patients only when TTI>300 minutes (TTI<300: poor CPC: 145 mL versus good CPC: 93 mL; P=0.56 and TTI>300: poor CPC: 217 mL versus good CPC: 33 mL; P<0.01). After adjusting for age and baseline National Institutes of Health Stroke Scale score, TTI<300 emerged as an independent predictor of clinical improvement in poor CPC patients (OR, 6.6; 95% CI, 1.01-44.3; P=0.05) but not in good CPC patients. In a logistic regression, good CPC independently predicted clinical improvement after adjusting for TTI, admission National Institutes of Health Stroke Scale score, and age (OR, 12.5; 95% CI, 1.6-74.8; P=0.016).

CONCLUSIONS

Good CPC predicts better clinical response to intra-arterial treatment beyond 5 hours from onset. In patients with stroke receiving endovascular treatment, identification of good CPC may help physicians when considering pursuing recanalization efforts in late time windows.

Acute stroke thrombolysis: time to dispense with the clock and move to tissue-based decision making?

Currently, imaging is predominantly used to exclude patients for thrombolysis, rather than identify patients most likely to benefit. This means that patients are being selected for treatment without reference to tissue pathophysiology. Imaging of specific stroke pathophysiology may be the key to selecting patients most likely to benefit from thrombolysis, and could revolutionize acute stroke assessment and treatment. The technology is available to identify the acute infarct core and possibly the penumbra, via magnetic resonance diffusion-weighted imaging, and both magnetic resonance- and computed tomography-perfusion imaging techniques. However, these modalities require fine tuning before they can be reliably implemented in a routine clinical setting.

Quantitative MRI reveals the elderly ischemic brain is susceptible to increased early blood-brain barrier permeability following tissue plasminogen activator related to claudin 5 and occludin disassembly

Great uncertainty exists as to whether aging enhances the detrimental effects of tissue plasminogen activator (tPA) on vascular integrity of the ischemic brain. We hypothesized that tPA treatment would augment ischemic injury by causing increased blood-brain barrier (BBB) breakdown as determined by quantitative serial T(1) and T(2) magnetic resonance imaging (MRI), and the transfer constant for gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA) from blood to brain in aged (18 to 20 months) compared with young (3 to 4 months) Wistar rats after middle cerebral artery occlusion, mediated through the acute disassembly of claudin 5 and occludin. Increased T(2) values over the first hour of postreperfusion were independently augmented following treatment with tPA (P<0.001) and aging (P<0.01), supporting a synergistic effect of tPA on the aged ischemic brain. Blood-brain barrier permeability for Gd-DTPA (K(Gd)) was substantial following reperfusion in all animal groups and was exacerbated by tPA treatment in the elderly rat (P<0.001). The frequency of hematoma formation was proportionately increased in the elderly ischemic brain (P<0.05). Both tPA and age independently increased claudin 5 and occludin phosphorylation during ischemia. Early BBB permeability detected by quantitative MRI following ischemic stroke is enhanced by increased age and tPA and is related to claudin 5 and occludin phosphorylation.

Hospital-based management of acute ischemic stroke following intravenous thrombolysis

Timely administration of proven therapies remains the primary goal in acute stroke care. Following reperfusion therapy with intravenous thrombolysis, medical and neurological complications may develop in the hospitalized patient with acute ischemic stroke. Medical complications may include deep venous thrombosis, pulmonary embolism, aspiration, systemic infections and neuropsychiatric disturbances. Neurologic complications may include symptomatic intracranial hemorrhage, cerebral edema with elevated intracranial pressure, and post-stroke seizures. Early initiation of preventative strategies and proper management of common complications may improve both short-term and long-term outcomes. Here we review evidence-based management strategies for hospitalized acute ischemic stroke patients following intravenous thrombolysis.

Clinical outcome after mechanical recanalization as mono- or adjunctive therapy in acute stroke: importance of time to recanalization

BACKGROUND

The clinical benefit of mechanical recanalization procedures for acute stroke is still a matter of debate. We report the clinical and imaging results of 34 consecutive patients, focusing on time aspects (i.e. vessel occlusion time and procedure duration).

METHODS

During a 3-year period, 34 stroke patients with large-vessel occlusion (anterior circulation, n = 19; posterior circulation, n = 15) were treated with several mechanical recanalization devices with (n = 17) or without prior intravenous thrombolysis. Clinical and imaging data before (NIHSS) and after treatment [(mRS) 3 and 6-30 months] were analyzed. The angiographic outcome (TIMI score), complication rates, and procedural issues (i.e. procedure duration and vessel occlusion time) were assessed.

RESULTS

The median NIHSS on admission was 17. Successful recanalization (TIMI 2 and 3) was achieved in 23 (68%) patients. The median time from symptom onset to recanalization was 330 min, and the median time from angiography to recanalization was 101 min. Six (18%) patients had a good clinical outcome (3-month mRS ≤2), and 10 (29%) died. The vessel occlusion time was significantly shorter in patients with a good compared to poor clinical outcome (247 vs. 348 min, p = 0.024). In the subgroup of anterior circulation stroke, successful recanalization, and no symptomatic intracranial hemorrhage (n = 11), there was a strong correlation between vessel occlusion time and clinical outcome (r = 0.711, p = 0.014).

CONCLUSIONS

The rate of vessel recanalization with endovascular therapy is promising. Nevertheless, the long-term clinical outcome is still disadvantageous in the majority of patients, presumably due to too long vessel occlusion times. Better strategies for patient selection and optimization of recanalization strategies (i.e. shorter time intervals to vessel patency) are warranted.

Radiological investigation of acute stroke 1: non-enhanced computed tomography

Radiology plays a central part in the acute stroke management pathway, with its role now widened beyond establishing the diagnosis. This article reviews the role of the non-enhanced computed tomography brain scan, particularly focusing on the hyper-acute presentation of stroke from a radiological perspective.

Early ischemic change on CT versus diffusion-weighted imaging for patients with stroke receiving intravenous recombinant tissue-type plasminogen activator therapy: stroke acute management with urgent risk-factor assessment and improvement (SAMURAI) rt-PA registry

BACKGROUND AND PURPOSE

Alberta Stroke Programme Early CT Score (ASPECTS) is a quantitative topographical score to evaluate early ischemic change in the middle cerebral arterial territory on CT as well as on diffusion-weighted imaging (DWI). The aim of the present study was to elucidate the relationship between CT-ASPECTS and DWI-ASPECTS for patients with hyperacute stroke and their associations with outcomes after recombinant tissue-type plasminogen activator therapy based on a multicenter registry.

METHODS

ASPECTS was assessed on both CT and DWI before intravenous 0.6 mg/kg alteplase in 360 patients with stroke (119 women, 71 ± 11 years old). The outcomes were symptomatic intracerebral hemorrhage within 36 hours and independence at 3 months defined by a modified Rankin Scale score of 0 to 2.

RESULTS

DWI-ASPECTS was positively correlated with CT-ASPECTS (ρ=0.511, P<0.001) and was lower than CT-ASPECTS (median 8 [interquartile range, 6 to 9] versus 9 [8 to 10], P<0.001). Higher baseline National Institutes of Health Stroke Scale score (standardized partial regression coefficient [β] 0.061, P<0.001) and cardioembolic stroke (β 0.35, P<0.001) were related to this discrepancy. The area under the receiver operating characteristic curve for predicting sICH (12 patients) using ASPECTS was 0.673 (95% CI, 0.503 to 0.807) by CT and 0.764 (95% CI, 0.635 to 0.858) by DWI (P=0.275). The area for predicting independence at 3 months (192 patients) was 0.621 (0.564 to 0.674) by CT and 0.639 (0.580 to 0.694) by DWI (P=0.535).

CONCLUSIONS

For patients with hyperacute stroke, DWI-ASPECTS scored approximately 1 point lower than CT-ASPECTS. Both CT-ASPECTS and DWI-ASPECTS were useful predictors of symptomatic intracerebral hemorrhage and independence at 3 months after recombinant tissue-type plasminogen activator.