Early infarct FLAIR hyperintensity is associated with increased hemorrhagic transformation after thrombolysis

Endovascular thrombectomy in wake-up stroke guided by arterial spin-labeling and fluid-attenuated inversion recovery versus diffusion-weighted imaging mismatch on MRI

OBJECTIVE

This purpose of this study is to investigate the effectiveness and safety of utilizing the arterial spin-labeling (ASL) combined with diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) combined with DWI double mismatch in the endovascular treatment of patients diagnosed with wake-up stroke (WUS).

METHODS

In this single-center trial, patients diagnosed with WUS underwent thrombectomy if acute ischemic lesions were observed on DWI indicating large precerebral circulation occlusion. Patients with no significant parenchymal hypersignal on FLAIR and ASL imaging showing a hypoperfusion tissue to infarct core volume ratio of at least 1.2 were included. The participants were divided into groups receiving endovascular thrombectomy plus medical therapy or medical therapy alone, based on their subjective preference. Functional outcomes were assessed using the ordinal score on the modified Rankin scale (mRs) at 90 days, along with the rate of functional independence.

RESULTS

In this study, a total of 77 patients were included, comprising 38 patients in the endovascular therapy group and 39 patients in the medical therapy group. The endovascular therapy group exhibited more favorable changes in the distribution of functional prognosis measured by mRs at 90 days, compared to the medical therapy group (adjusted common odds ratio, 3.25; 95% CI, 1.03 to 10.26; P < 0.01). Additionally, the endovascular therapy group had a higher proportion of patients achieving functional independence (odds ratio, 4.0; 95% CI, 1.36 to 11.81; P < 0.01). Importantly, there were no significant differences observed in the incidence of intracranial hemorrhage or mortality rates between the two groups.

CONCLUSION

Guided by the ASL-DWI and FLAIR-DWI double mismatch, endovascular thrombectomy combined with standard medical treatment appears to yield superior functional outcomes in patients with WUS and large vessel occlusion compared to standard medical treatment alone.

Leukoaraiosis and stroke severity scores in post-rtPA intracerebral haemorrhage

Introduction

Post thrombolytic symptomatic intracerebral haemorrhage (sICH) is a major concern in patients who had acute ischaemic stroke. Leukoaraiosis (LA) is reported to be related with sICH after intravenous thrombolytic treatment. However, the influence of LA and stroke neurological and imaging severity scores is still debated.

Objective

To evaluate if LA or severity scores are related with sICH in patients who had acute ischaemic stroke who received thrombolytic therapy. And, predictors for sICH were also studied with adjustment of baseline severity scores.

Methods

This was a retrospective, analytical study. The inclusion criteria were adult patients diagnosed as acute ischaemic stroke who received the recombinant tissue plasminogen activator (rtPA) treatment within 4.5 hours. The study period was between May 2007 and November 2016. Predictors for sICH were determined using logistic regression analysis.

Results

During the study period, there were 504 eligible patients. Of those, 45 patients (8.92%) had sICH. Among nine factors in the final model for predicting sICH, there were four independent factors including previous antiplatelet therapy, previous anticoagulant therapy, presence of LA and hyperdense artery sign. The highest adjusted OR was previous anticoagulant therapy (5.08 with 95% CI of 1.18 to 11.83), while the LA factor had adjusted OR (95% CI) of 2.52 (1.01 to 6.30).

Conclusions

LA, hyperdense artery sign, previous antiplatelet therapy and previous anticoagulant therapy were associated with post-rtPA sICH. Further studies are required to confirm the results of this study.

Cytoskeletal protein breakdown and serum albumin extravasation in MRI DWI-T2WI mismatch area in acute murine cerebral ischemia

MRI diffusion-weighted imaging (DWI)-FLAIR mismatch is known as predictive of symptom onset within 4.5 h. This study assessed the breakdown of cytoskeletal protein and blood-brain barrier (BBB) in DWI-T2 mismatch. We employed occlusion of middle cerebral artery (MCAO) in C57BL/6 mice. We serially measured MRI including DWI and T2WI. After MRI, we prepared brain sections or samples and examined microtubule-associated protein 2 (MAP2) expression, alpha-fodrin degradation, extravasation of albumin and claudin-5 expression. In permanent or transient MCAO for 45 min, DWI hyperintensities was already found at 60 min without change of T2, showing DWI-T2 mismatch. In permanent MCAO, MAP2 expressions were preserved, and no extravasation of albumin was observed. In transient MCAO, MAP2 immunoreaction was already lost in the lateral part of the striatum. In both models, alpha-fodrin degradation was already detected. At 180 min, T2 hyperintensities appeared, where MAP2 signal was lost and albumin extravasation was found. At 24 h, hyperintensities of DWI and T2WI was found in the whole MCA territory, where MAP2 signal was completely lost with marked albumin extravasation and alpha-fodrin degradation. Immunoreaction for claudin-5 was preserved up to 180 min. DWI-T2 mismatch area may not always indicate intactness of cytoskeletal protein but shows preservation of BBB.

The association between the severity and distribution of white matter lesions and hemorrhagic transformation after ischemic stroke: A systematic review and meta-analysis

Background and purpose

As a part of the natural course of ischemic stroke, hemorrhagic transformation (HT) is a serious complication after reperfusion treatment, which may affect the prognosis of patients with ischemic stroke. White matter lesions (WMLs) refer to focal lesions on neuroimaging and have been suggested to indicate a high risk of HT. This systematic review and meta-analysis aimed to summarize current evidence on the relation between WML and HT.

Methods

This systematic review was prepared with reference to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched PubMed, Embase, Web of Science, and Cochrane Library databases for publications on WML and HT in patients with ischemic stroke. Odds ratios (ORs) and 95% confidence intervals (CIs) from eligible studies were combined to quantify the association between the severity of WML and the risk of HT. In addition, the descriptive analysis was adopted to evaluate the influence of different WML distributions on predicting HT.

Results

A total of 2,303 articles were identified after removing duplicates through database searching, and 41 studies were included in our final analysis. The meta-analysis showed that the presence of WML was associated with HT (OR = 1.62, 95%CI 1.08-2.43, p = 0.019) and symptomatic intracerebral hemorrhage (sICH) (OR = 1.64, 95%CI 1.17-2.30, p = 0.004), and moderate-to-severe WML indicated a high risk of HT (OR = 2.03, 95%CI 1.33-3.12, p = 0.001) and sICH (OR = 1.92, 95%CI 1.31-2.81, p < 0.001). The dose-response meta-analysis revealed risk effects of increasing the severity of WML on both HT and ICH. In addition, both periventricular WML (PWML) (five of seven articles) and deep WML (DWML) (five of six articles) were shown to be associated with HT.

Conclusions

White matter lesions are associated with overall HT and sICH in patients with ischemic stroke, and more severe WMLs indicate a high risk of HT and sICH. In addition, both PWML and DWMLs could be risk factors for HT.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier: PROSPERO CRD42022313467.

Fluid-Attenuated Inversion Recovery Hyperintense Ischemic Stroke Predicts Less Favorable 90-Day Outcome after Intravenous Thrombolysis

INTRODUCTION

The absence of an ischemic lesion on MRI fluid-attenuated inversion recovery (FLAIR) is helpful in predicting stroke onset within 4.5 h. However, some ischemic strokes become visible on FLAIR within 4.5 h. We hypothesized that the early lesion visibility on FLAIR may predict stroke outcome 90 days after intravenous (IV) thrombolysis, independent of time.

MATERIALS AND METHODS

We analyzed data from acute ischemic stroke patients presenting over the last 10 years who were screened with MRI and treated with IV thrombolysis within 4.5 h from onset. Three independent readers assessed whether ischemic lesions seen on diffusion-weighted imaging were also FLAIR positive based on visual inspection. Multivariable regression analyses were used to obtain an adjusted odds ratio of favorable clinical and radiological outcomes based on FLAIR positivity.

RESULTS

Of 297 ischemic stroke patients, 25% had lesion visibility on initial FLAIR. The interrater agreement for the FLAIR positivity assessment was 84% (κ = 0.604, 95% CI: 0.557-0.652). Patients with FLAIR-positive lesions had more right hemispheric strokes (57 vs. 41%, p = 0.045), were imaged later (129 vs. 104 min, p = 0.036), and had less frequent favorable 90-day functional outcome (49 vs. 63%, p = 0.028), less frequent early neurologic improvement (30 vs. 58%, p = 0.001), and more frequent contrast extravasation to the cerebrospinal fluid space (44 vs. 26%, p = 0.008).

CONCLUSIONS

Early development of stroke lesion on FLAIR within 4.5 h of onset is associated with reduced likelihood of favorable 90-day outcome after IV thrombolysis.

Fluid-Attenuated Inversion Recovery May Serve As a Tissue Clock in Patients Treated With Endovascular Thrombectomy

[Figure: see text].

Focal T2 and FLAIR hyperintensities within the infarcted area: A suitable marker for patient selection for treatment?

Background and purpose

Some authors use FLAIR imaging to select patients for stroke treatment. However, the effect of hyperintensity on FLAIR images on outcome and bleeding has been addressed in only few studies with conflicting results.

Methods

466 patients with anterior circulation strokes were included in this study. They all were examined with MRI before intravenous or endovascular treatment. Baseline data and 3 months outcome were recorded prospectively. Focal T2 and FLAIR hyperintensities within the ischemic lesion were evaluated by two raters, and the PROACT II classification was applied to assess bleeding complications on follow up imaging. Logistic regression analysis was used to determine predictors of bleeding complications and outcome and to analyze the influence of T2 or FLAIR hyperintensity on outcome.

Results

Focal hyperintensities were found in 142 of 307 (46.3%) patients with T2 weighted imaging and in 89 of 159 (56%) patients with FLAIR imaging. Hyperintensity in the basal ganglia, especially in the lentiform nucleus, on T2 weighted imaging was the only independent predictor of any bleeding after reperfusion treatment (33.8% in patients with vs. 18.2% in those without; p = 0.003) and there was a non-significant trend for more bleedings in patients with FLAIR hyperintensity within the basal ganglia (p = 0.069). However, there was no association of hyperintensity on T2 weighted or FLAIR images and symptomatic bleeding or worse outcome.

Conclusion

Our results question the assumption that T2 or FLAIR hyperintensities within the ischemic lesion should be used to exclude patients from reperfusion therapy, especially not from endovascular treatment.

Risk Factors for Hemorrhagic Transformation After Intravenous Thrombolysis in Acute Cerebral Infarction: A Retrospective Single-Center Study

OBJECTIVE

To investigate the risk factors for hemorrhagic transformation (HT) after intravenous thrombolysis using a recombinant tissue plasminogen activator (r-tPA) in acute cerebral infarction.

METHODS

Patients with acute cerebral infarction receiving r-tPA thrombolysis in Shanghai Eastern Hospital were retrospectively studied. Based on the cranial computed tomography or magnetic resonance imaging examination, after the intravenous thrombolysis, the patients were divided into 2 groups: an HT group and a non-HT group. The information was collected before or after thrombolysis.

RESULTS

A total of 162 patients were included in the analysis. The age ranged from 25 to 86 years, with an average age of 65.6 ± 10.6 years. The average time from disease onset to thrombolysis was 188 ± 53.1 minutes. Cranial computed tomography or magnetic resonance imaging showed that 20 patients (12.3%) had HT after thrombolysis. Using univariate analysis, history of atrial fibrillation, positive expression of urinary protein, and high National Institutes of Health Stroke Scale (NIHSS) score before thrombolysis, we found that there was a significant difference between the HT and non-HT group (P < 0.05) in the level of mean systolic pressure (MSP) 24 hours after thrombolysis. Multivariate logistic regression analysis indicated that age ≥80 years, MSP ≥140 mm Hg, NIHSS score, and fibrinogen concentration before thrombolysis were risk factors for HT after thrombolysis in patients with acute cerebral infarction.

CONCLUSIONS

Age, MSP, NIHSS score, and fibrinogen concentration before thrombolysis are risk factors for HT after thrombolysis in acute cerebral infarction. These 4 factors should be carefully taken into account before thrombolysis.

Wake-up stroke: Dawn of a new era

Wake-up stroke or stroke with unclear onset of symptoms is known to occur in one-fourth of ischemic stroke patients. These patients are not considered for thrombolytic therapy based on time designation of their symptom onset as per the current guidelines. Observational studies have investigated the pathophysiology and suggested actual onset of symptoms to be approximate to the awakening time for these patients. Use of advanced imaging modalities in these patients tends to identify favorable patient profiles for thrombolysis. Results of the ongoing trials will likely beckon a seminal juncture in stroke therapy and deliver critical modifications in the current treatment guidelines for thrombolysis in this substantial, yet neglected, group of stroke patients. In this article, we have reviewed the predisposing factors, preferred imaging modalities and various ongoing thrombolytic and endovascular trials to date for patients with unclear time of symptom onset or who wake up with stroke symptoms.

Elevations in Tissue Fluid-Attenuated Inversion Recovery Signal Are Related to Good Functional Outcome after Thrombolytic Treatment

BACKGROUND

Early elevations in the parenchymal signal intensity on T2-weighted images, including fluid-attenuated inversion recovery (FLAIR) sequences, within the ischemic territory are considered as a marker of successful recanalization following thrombolytic treatment. In this study, our aim was to assess whether quantitatively determined FLAIR hyperintensity increases could be predictive of improved functional outcome in patients with acute ischemic stroke.

METHODS

Patients receiving intravenous thrombolysis for proximal anterior circulation strokes were included in the study. FLAIR hyperintensity ratio was determined on magnetic resonance imaging obtained within 72 hours of symptom onset. Univariate and multivariate analyses were performed to determine predictors of good functional outcome at 90 days.

RESULTS

The study population was composed of 65 patients. The median (interquartile range) FLAIR hyperintensity ratio was significantly higher among patients with good functional outcome (modified Rankin Scale score ≤ 3 at day 90, 1.4 [1.2-1.7] versus 1.2 [1.1-1.4], P = .005). Patients with a FLAIR hyperintensity ratio of 1.3 or higher were 4.4 (95% confidence interval 1.6-12.7) times more likely to be independent functionally at the end of 3 months. Higher admission National Institutes of Health Stroke Scale score and age, together with lower FLAIR hyperintensity ratio (P = .006), were found to be significantly and independently related to unfavorable outcome at 90-day follow-up in multivariate analyses.

CONCLUSIONS

Our findings suggest that a rise in FLAIR hyperintensity signal within the ischemic tissue is suggestive of favorable outcome in patients undergoing intravenous thrombolysis. This tissue marker of favorable outcome is irrespective of other parameters that are crucial in the prognosis of ischemic stroke, such as age and stroke severity.

Infarction Distribution Pattern in Acute Stroke May Predict the Extent of Leptomeningeal Collaterals

Objective

The aim of this study was to evaluate whether the distribution pattern of early ischemic changes in the initial MRI allows a practical method for estimating leptomeningeal collateralization in acute ischemic stroke (AIS).

Methods

Seventy-four patients with AIS underwent MRI followed by conventional angiogram and mechanical thrombectomy. Diffusion restriction in Diffusion weighted imaging (DWI) and correlated T2-hyperintensity of the infarct were retrospectively analyzed and subdivided in accordance with Alberta Stroke Program Early CT score (ASPECTS). Patients were angiographically graded in collateralization groups according to the method of Higashida, and dichotomized in 2 groups: 29 subjects with collateralization grade 3 or 4 (well-collateralized group) and 45 subjects with grade 1 or 2 (poorly-collateralized group). Individual ASPECTS areas were compared among the groups.

Results

Means for overall DWI-ASPECTS were 6.34 vs. 4.51 (well vs. poorly collateralized groups respectively), and for T2-ASPECTS 9.34 vs 8.96. A significant difference between groups was found for DWI-ASPECTS (p<0.001), but not for T2-ASPECTS (p = 0.088). Regarding the individual areas, only insula, M1-M4 and M6 showed significantly fewer infarctions in the well-collateralized group (p-values <0.001 to 0.015). 89% of patients in the well-collateralized group showed 0–2 infarctions in these six areas (44.8% with 0 infarctions), while 59.9% patients of the poor-collateralized group showed 3–6 infarctions.

Conclusion

Patients with poor leptomeningeal collateralization show more infarcts on the initial MRI, particularly in the ASPECTS areas M1 to M4, M6 and insula. Therefore DWI abnormalities in these areas may be a surrogate marker for poor leptomeningeal collaterals and may be useful for estimation of the collateral status in routine clinical evaluation.

[Neurovisualisation predictors of malignant cerebral infarction and hemorrhagic transformation]

Neuroimaging plays a central role in the assessment of patients with acute ischemic stroke. Within a few minutes, modern multimodal imaging protocols can provide one with comprehensive information about prognosis, management, and outcome of the disease, and may detect changes in the intracranial structures reflecting severity of the ischemic injury depicted by four Ps: parenchyma (of the brain), pipes (i.e., the cerebral blood vessels), penumbra, and permeability (of the blood brain barrier). In this article, we have reviewed neuroradiological predictors of malignant middle cerebral artery infarction and hemorrhagic transformation in light of the aforementioned four Ps.

White Matter Lesions Double the Risk of Post-Thrombolytic Intracerebral Hemorrhage

BACKGROUND AND PURPOSE

Cerebral white matter lesions (WMLs), a surrogate for small-vessel disease, are common in patients with stroke and may be related to an increased intracranial bleeding risk after intravenous thrombolysis in acute ischemic stroke. We aimed to investigate the risk of symptomatic intracerebral hemorrhage (sICH) in the presence of WMLs in a large cohort of ischemic stroke patients treated with intravenous thrombolysis.

METHODS

We included 2485 consecutive patients treated with intravenous thrombolysis at the Helsinki University Central Hospital. WMLs were scored according to 4 previously published computed tomography visual rating scales from all baseline head scans. A sICH was classified according to the European Cooperative Acute Stroke Study II criteria. The associations of sICH with nominal, ordinal, and continuous variables were analyzed in a univariate binary regression model and adjusted in multivariate binary regression models.

RESULTS

In univariate and multivariate regression analyses, all 4 tested visual WML rating scales (as continuous variables or dichotomized at different cutoff points) were associated with increased risk of sICH. In binary analyses, WML doubled the bleeding risk: the odds ratios of all 4 visual rating scales ranged from 2.22 (95% confidence interval, 1.49-3.30) to 2.70 (1.87-3.90) in univariable and from 2.00 (1.26-3.16) to 2.62 (1.71-4.02) in multivariable analyses. The multivariable-adjusted odds ratio for the association of high load of WMLs with remote parenchymal hemorrhage was 4.11 (2.38-7.10).

CONCLUSIONS

WMLs visible on computed tomography are associated with a more than doubled risk of sICH in patients treated with intravenous thrombolysis for acute ischemic stroke.

Multiple extra-ischemic hemorrhages following intravenous thrombolysis in a patient with Trousseau syndrome: case study

Background

Intracerebral hemorrhage is the most feared complication of intravenous thrombolysis for acute ischemic stroke. Such hemorrhage usually occurs within or at the margin of ischemic or manifestly infarcted brain tissue. A patient with Trousseau syndrome who developed multiple extra-ischemic hemorrhages following intravenous thrombolysis is described.

Case description

An 80-year-old Japanese man with no other underlying disease was diagnosed with unresectable advanced lung cancer (stage IV) without brain metastasis and had not yet been treated. The patient suddenly presented with disturbance of consciousness, right hemiplegia, and total aphasia, and was admitted to our hospital. Magnetic resonance imaging revealed acute cerebral infarction extending from the basal ganglia to the corona radiata of the left cerebrum and multiple small areas of bilateral cerebral cortices. Cardiogenic cerebral embolism was considered among the differential diagnoses, but the brain natriuretic peptide level was within the normal range, and no arrhythmias such as atrial fibrillation were observed. With no other causes, the patient was diagnosed with Trousseau syndrome due to hypercoagulability associated with the advanced lung cancer. The patient received intravenous tissue plasminogen activator (t-PA) at 96 minutes after onset of symptoms. His symptoms partially improved, but they suddenly deteriorated at 84 minutes after the thrombolysis. A computed tomography (CT) scan immediately after the neurological deterioration revealed a subcortical hemorrhage in the left occipital lobe. A repeat CT scan the day after onset showed enlargement of the left occipital hemorrhage and two new subcortical hemorrhages in the right frontal and right temporal lobes. These hemorrhages were located in areas remote from the acute ischemic lesions.

Conclusion

To the best of our knowledge, this is the first reported case of multiple extra-ischemic hemorrhages following intravenous thrombolysis in a patient with Trousseau syndrome. The course of this case suggests that intravenous t-PA administration for acute ischemic stroke with Trousseau syndrome may be associated with a higher risk of intracranial hemorrhage.

MRI-guided selection of patients for treatment of acute ischemic stroke

PURPOSE OF REVIEW

To summarize what is known about the use of MRI in acute stroke treatment (predominantly thrombolysis), to examine the assumptions and theories behind the interpretation of magnetic resonance images of acute ischemic stroke and how they are used to select patients for therapies, and to suggest directions for future research.

RECENT FINDINGS

Recent studies have been contradictory about the usefulness of MRI in selecting patients for treatment. New MRI models for selecting patients have emerged that focus not only on the ischemic penumbra but also on the infarct core. Fixed time-window selection parameters are being replaced by timing-based individualized MRI stroke features. New ways to interpret traditional MRI stroke sequences are emerging.

SUMMARY

Although the efficacy of acute stroke treatment is time dependent, the use of fixed time windows cannot account for individual differences in infarct evolution, which could potentially be detected with MRI. Although MRI shows promise for identifying patients who should be treated, as well as excluding patients who should not be treated, definitive evidence is still lacking. Future research should focus on validating the use of MRI to select patients for intravenous therapies in extended time windows.

Brain edema predicts outcome after nonlacunar ischemic stroke

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.

Wake-up stroke and stroke of unknown onset: a critical review

Patients, who wake up with an ischemic stroke, account for a large number of the total stroke population, due to circadian morning predominance of stroke. Currently, this subset of patients is excluded from revascularization-therapy since no exact time of onset is known. A large group of these patients might be eligible for therapy. In this review, we assessed the current literature about the hypothesis that wake-up-strokes occur just prior on awakening and if this subgroup differs in characteristics compared to the overall stroke population. We looked at the safety and efficacy of thrombolysis and interventional techniques in the group of patients with unknown stroke-onset. We performed a meta-analysis of the diagnostic accuracy of the diffusion-FLAIR mismatch in identifying stroke within 3 and 4.5 h. The different imaging-selection criteria that can be used to treat these patients are discussed. Additional research on imaging findings associated with recent stroke and penumbral imaging will eventually lead to a shift from a rigid time-frame based therapy to a tissue-based individualized treatment approach.

Safety of intravenous tissue plasminogen activator administration with computed tomography evidence of prior infarction

BACKGROUND

Prior stroke within 3 months excludes patients from thrombolysis; however, patients may have computed tomography (CT) evidence of prior infarct, often of unknown time of origin. We aimed to determine if the presence of a previous infarct on pretreatment CT is a predictor of hemorrhagic complications and functional outcomes after the administration of intravenous (IV) tissue plasminogen activator (tPA).

METHODS

We retrospectively analyzed consecutive patients treated with IV tPA at our institution from 2009-2011. Pretreatment CTs were reviewed for evidence of any prior infarct. Further review determined if any hemorrhagic transformation (HT) or symptomatic intracerebral hemorrhage (sICH) were present on repeat CT or magnetic resonance imaging. Outcomes included sICH, any HT, poor functional outcome (modified Rankin Scale score of 4-6), and discharge disposition.

RESULTS

Of 212 IV tPA-treated patients, 84 (40%) had evidence of prior infarct on pretreatment CT. Patients with prior infarcts on CT were older (median age, 72 versus 65 years; P=.001) and had higher pretreatment National Institutes of Health Stroke Scale scores (median, 10 versus 7; P=.023). Patients with prior infarcts on CT did not experience more sICH (4% versus 2%; P=.221) or any HT (18% versus 14%; P=.471). These patients did have a higher frequency of poor functional outcome at discharge (82% versus 50%; P<.001) and were less often discharged to home or inpatient rehabilitation center (61% versus 73%; P=.065).

CONCLUSIONS

Visualization of prior infarcts on pretreatment CT did not predict an increased risk of sICH in our study and should not be viewed as a reason to withhold systemic tPA treatment after clinically evident strokes within 3 months were excluded.

Fluid-attenuated inversion recovery hyperintensity correlates with matrix metalloproteinase-9 level and hemorrhagic transformation in acute ischemic stroke

BACKGROUND AND PURPOSE

Matrix metalloproteinase-9 (MMP-9) is elevated in patients with acute stroke who later develop hemorrhagic transformation (HT). It is controversial whether early fluid-attenuated inversion recovery (FLAIR) hyperintensity on brain MRI predicts hemorrhagic transformation (HT). We assessed whether FLAIR hyperintensity was associated with MMP-9 and HT.

METHODS

We analyzed a prospectively collected cohort of acute stroke subjects with acute brain MRI images and MMP-9 values within the first 12 hours after stroke onset. FLAIR hyperintensity was measured using a signal intensity ratio between the stroke lesion and corresponding normal contralateral hemisphere. MMP-9 was measured using enzyme-linked immunosorbent assay. The relationships between FLAIR ratio (FR), MMP-9, and HT were evaluated.

RESULTS

A total of 180 subjects were available for analysis. Patients were imaged with brain MRI at 5.6±4.3 hours from last seen well time. MMP-9 blood samples were drawn within 7.7±4.0 hours from last seen well time. The time to MRI (r=0.17, P=0.027) and MMP-9 level (r=0.29, P<0.001) were each associated with FR. The association between MMP-9 and FR remained significant after multivariable adjustment (P<0.001). FR was also associated with HT and symptomatic hemorrhage (P=0.012).

CONCLUSIONS

FR correlates with both MMP-9 level and risk of hemorrhage. FLAIR changes in the acute phase of stroke may predict hemorrhagic transformation, possibly as a reflection of altered blood-brain barrier integrity.