Mechanism of multiple infarcts in multiple cerebral circulations on diffusion-weighted imaging

Exploring the relationship between embolic acute stroke distribution and supra-aortic vessel patency: key findings from an in vitro model study

BACKGROUND

We investigated differences in intracranial embolus distribution through communicating arteries in relation to supra-aortic vessel (SAV) patency.

METHODS

For this experimental analysis, we created a silicone model of the extracranial and intracranial circulations using a blood-mimicking fluid under physiological pulsatile flow. We examined the sequence of embolus lodgment on injecting 104 frangible clot analogues (406 emboli) through the right internal carotid artery (CA) as SAV patency changed: (a) all SAV patent (baseline), (b) emboli from a CA occlusion, (c) emboli contralateral to a CA occlusion and (d) occlusion of the posterior circulation. The statistical analysis included a descriptive analysis of thrombi location after occlusion (absolute and relative frequencies). Sequences of occlusions were displayed in Sankey flow charts for the four SAV conditions. Associations between SAV conditions and occlusion location were tested by Fisher's exact test. Two-sided p values were compared with a significance level of 0.05.

RESULTS

The total number of emboli was 406 (median fragments/clot: 4 (IQR: 3-5)). Embolus lodgment was dependent on SAV patency (p<0.0001). In all scenarios, embolism lodging in the anterior cerebral artery (ACA) occurred after a previous middle cerebral artery (MCA) embolism (MCA first lodge: 96%, 100/104). The rate of ipsilateral ACA embolism was 28.9% (28/97) at baseline, decreasing significantly when emboli originated from an occluded CA (16%, 14/88). There were more bihemispheric embolisations in cases of contralateral CA occlusion (37%, 45/122), with bilateral ACA embolisms preceding contralateral MCA embolism in 56% of cases (14/25 opposite MCA and ACA embolism).

CONCLUSIONS

All emboli in the ACA occurred after a previous ipsilateral MCA embolism. Bihemispheric embolisms were rare, except when there was a coexisting occlusion in either CA, particularly in cases of a contralateral CA occlusion.

Concurrent Middle Cerebral Artery and Basilar Artery Occlusions Treated With Mechanical Thrombectomy in a Patient With Active COVID-19 Infection

We report a rare case of acute ischemic stroke from concurrent large vessel occlusions (LVOs) and subsequent successful mechanical thrombectomy revascularization in a patient with active coronavirus disease 2019 (COVID-19) pneumonia. A 59-year-old woman presented to the emergency department after one week of intermittent chest pain, dyspnea, and diarrhea found to have COVID-19 pneumonia. On hospital day three, the patient developed acute altered mental status and hemiparesis with a National Institutes of Health Stroke Scale (NIHSS) of 22. CT with angiography demonstrated concurrent occlusions of the basilar artery and the M1 segment of the right middle cerebral artery (MCA) without intracranial hemorrhage. The patient was taken for urgent mechanical thrombectomy of the basilar artery, followed by the MCA, both of which were successful (thrombolysis in cerebral infarction (TICI) 3 and 2B) and timely. Despite early revascularization, the patient did not improve clinically with absent brainstem reflexes and a full MCA territorial infarct on imaging. This case describes a rare stroke syndrome of concurrent LVOs with rapid infarct progression despite timely revascularization. This example illustrates a severe cerebrovascular complication of active COVID-19 infection and the importance of vigilance regarding stroke prevention and neurological examination monitoring.

Characteristics of Multiple Acute Concomitant Cerebral Infarcts Involving Different Arterial Territories

(1) Background: Multiple acute concomitant cerebral infarcts (MACCI) are relatively uncommon. Data regarding the characteristics and outcomes of patients with MACCI are lacking. We, therefore, aimed to characterize the clinical features of MACCI. (2) Methods: Patients with MACCI were identified from a prospective registry of stroke patients admitted to a tertiary teaching center. Patients with an acute single embolic stroke (ASES) involving only one vascular bed served as controls. (3) Results: MACCI was diagnosed in 103 patients who were compared to 150 patients with ASES. MACCI patients were significantly older (p = 0.010), more often had a history of diabetes (p = 0.011) and had lower rates of ischemic heart disease (p = 0.022). On admission, MACCI patients had significantly higher rates of focal signs (p < 0.001), an altered mental state (p < 0.001) and seizures (p = 0.036). The favorable functional outcome was significantly less common in patients with MACCI (p = 0.006). In the multivariable analysis, MACCI was associated with lower chances of achieving favorable outcomes (odds ratio: 0.190, 95% CI: 0.070-0.502). (4) Conclusions: There are important differences in clinical presentation, comorbidities and outcomes between MACCI and ASES. MACCI is less often associated with favorable outcomes and could represent a more severe form of a stroke compared with a single embolic stroke.

Distinct lesion features and underlying mechanisms in patients with acute multiple infarcts in multiple cerebral territories

Objective

To determine the etiology spectrum and lesion distribution patterns of patients with acute multiple infarcts in multiple cerebral territories (AMIMCT) and provide guidance for treatment and prevention strategies in these patients.

Methods

Patients with acute ischemic stroke diagnosed using diffusion-weighted imaging (DWI) were consecutively included in this study between June 2012 and Apr 2022. AMIMCT was defined as non-contiguous focal lesions located in more than one cerebral territory with acute neurological deficits. We retrospectively analyzed the clinical and imaging characteristics, etiology spectra and underlying mechanisms in patients with and without AMIMCT. Infarct lesion patterns on DWI and their relevance to etiology were further discussed.

Results

A total of 1,213 patients were enrolled, of whom 145 (12%) were diagnosed with AMIMCT. Patients with AMIMCT tended to be younger (P = 0.016), more often female (P = 0.001), and exhibited less common conventional vascular risk factors (P < 0.05) compared to those without AMIMCT. The constitution of the Trial of Org 10,172 in Acute Stroke Treatment classification was significantly different between patients with and without AMIMCT (P = 0.000), with a higher proportion of stroke of other determined causes (67.6% vs. 12.4%). For detailed etiologies, autoimmune or hematologic diseases were the most common (26.2%) etiologies of AMIMCT, followed by periprocedural infarcts (15.2%), cardioembolism (12.4%), tumor (12.4%), large artery atherosclerosis (10.3%), and sudden drop in blood pressure (8.3%). Hypercoagulability and systemic hypoperfusion are common underlying mechanisms of AMIMCT. Distinctive lesion distribution patterns were found associated with stroke etiologies and mechanisms in AMIMCT. Most of patients with large artery atherosclerosis (73.3%), autoimmune/hematologic diseases (57.9%) manifested the disease as multiple infarct lesions located in bilateral supratentorial regions. However, 66.7% of cardioembolism and 83.8% of cardiovascular surgery related stroke presented with both supratentorial and infratentorial infarct lesions.

Conclusion

The etiologies and mechanisms of patients with AMIMCT were more complex than those without AMIMCT. The distribution characteristics of infarct lesions might have important implications for the identification of etiology and mechanism in the future, which could further guide and optimize clinical diagnostic strategies.

Deep profiling of multiple ischemic lesions in a large, multi-center cohort: Frequency, spatial distribution, and associations to clinical characteristics

Background purpose

A substantial number of patients with acute ischemic stroke (AIS) experience multiple acute lesions (MAL). We here aimed to scrutinize MAL in a large radiologically deep-phenotyped cohort.

Materials and methods

Analyses relied upon imaging and clinical data from the international MRI-GENIE study. Imaging data comprised both Fluid-attenuated inversion recovery (FLAIR) for white matter hyperintensity (WMH) burden estimation and diffusion-weighted imaging (DWI) sequences for the assessment of acute stroke lesions. The initial step featured the systematic evaluation of occurrences of MAL within one and several vascular supply territories. Associations between MAL and important imaging and clinical characteristics were subsequently determined. The interaction effect between single and multiple lesion status and lesion volume was estimated by means of Bayesian hierarchical regression modeling for both stroke severity and functional outcome.

Results

We analyzed 2,466 patients (age = 63.4 ± 14.8, 39% women), 49.7% of which presented with a single lesion. Another 37.4% experienced MAL in a single vascular territory, while 12.9% featured lesions in multiple vascular territories. Within most territories, MAL occurred as frequently as single lesions (ratio ∼1:1). Only the brainstem region comprised fewer patients with MAL (ratio 1:4). Patients with MAL presented with a significantly higher lesion volume and acute NIHSS (7.7 vs. 1.7 ml and 4 vs. 3, p FDR < 0.001). In contrast, patients with a single lesion were characterized by a significantly higher WMH burden (6.1 vs. 5.3 ml, p FDR = 0.048). Functional outcome did not differ significantly between patients with single versus multiple lesions. Bayesian analyses suggested that the association between lesion volume and stroke severity between single and multiple lesions was the same in case of anterior circulation stroke. In case of posterior circulation stroke, lesion volume was linked to a higher NIHSS only among those with MAL.

Conclusion

Multiple lesions, especially those within one vascular territory, occurred more frequently than previously reported. Overall, multiple lesions were distinctly linked to a higher acute stroke severity, a higher total DWI lesion volume and a lower WMH lesion volume. In posterior circulation stroke, lesion volume was linked to a higher stroke severity in multiple lesions only.

Coexistent cerebral small vessel disease and multiple infarctions predict recurrent stroke

BACKGROUND AND PURPOSE

To investigate the association of different status of cerebral small vessel disease (CSVD) and infarction number with recurrence after acute minor stroke and transient ischaemic attack (TIA).

METHODS

This study was a post hoc analysis of the Clopidogrel in High-risk Patients with Acute Nondisabling Cerebrovascular Events (CHANCE) trial, and includes 886 patients with acute minor stroke and TIA. The status of CSVD and infarction number was recorded for each individual. Infarction number were classified as multiple acute infarctions (MAIs≥2), single acute infarction (SAI =1), and non-acute infarction (NAI =0). The CSVD burden were grouped into non-CSVD (0 score) and CSVD (1-4 score). The primary outcome was a recurrent stroke at the 1-year follow-up. The secondary outcomes were recurrent ischaemic stroke, composite vascular event (CVE), and TIA. We analyzed the relationships between different status of CSVD burden and infarction pattern with the risk of outcomes using multivariable Cox regression models.

RESULTS

Among all 886 patients included in present analysis, recurrent stroke was occurred in 93 (10.5%) patients during 1-year follow-up. After adjusted for all potential covariates, compared with patients with non-CSVD and NAI, patients with CSVD and MAIs were associated with approximately 9.5-fold increased risk of recurrent stroke at 1 year (HR 9.560, 95% CI 1.273-71.787, p=0.028). Similar results observed in ischaemic stroke and CVE.

CONCLUSION

The status of CSVD and infarction number predicted recurrent stroke in patients with acute minor stroke and TIA, especially for those with coexistent CSVD and MAIs.

Patterns of Infarction on MRI in Patients With Acute Ischemic Stroke and Cardio-Embolism: A Systematic Review and Meta-Analysis

Background: Cardioembolic strokes are common however atrial fibrillation, the most common cause, is often asymptomatic and difficult to detect. There is evidence that infarct topography and volume on magnetic resonance imaging may be associated with specific stroke etiologies.

Aim: A systematic review and meta-analysis were undertaken to summarize the available evidence on the association between stroke etiology, infarct topography, and volume.

Methods: A systematic review was conducted using Medline (OVID), Embase (OVID), and PubMed databases. Hand searches of the gray literature and of reference lists in relevant articles were also performed. A quality assessment was undertaken, based on the STROBE checklist. For each study, the number of patients with and without a CE source of stroke and infarct topography was collected and outcomes presented as odds ratios (OR) with 95% CI and p-values.

Results: Four thousand eight hundred and seventy-three patients with ischemic stroke were included, of whom 1,559 were determined to have a CE source. Bilateral infarcts (OR 3.41; 95% CI 2.20–5.29; p < 0.0001) and multiple territory infarcts (OR 1.57; 95% CI 1.12–2.21; p = 0.009) were more common in patients with a CE source of stroke, than patients without a CE source. Lacunar infarcts (OR 0.49; 95% CI 0.31–0.80; p = 0.004) were more likely to occur in patients without a CE source. No significant difference between the frequency of multiple infarcts (OR 0.96; 95% CI 0.57–1.61; p = 0.87) anterior circulation (OR 1.45; 95% CI 0.83–2.53; p = 0.19) or posterior circulation infarcts (OR 1.06; 95% CI 0.72–1.57; p = 0.75), between the two groups were identified. Three out of four studies examining volume, found a significant association between increased infarct volume and CE source of stroke. A sensitivity analysis with cryptogenic and undetermined stroke sources assumed to be cardioembolic, did not alter the associations observed.

Conclusion: The findings of this systematic review and meta-analysis are broadly consistent with previous literature and provide more robust evidence on the association between infarct topography, volume and stroke etiology. Our findings may assist with refining cardiac investigations for patients with cryptogenic stroke, based on infarct topography.

Diagnostic accuracy of acute infarcts in multiple cerebral circulations for cardioembolic stroke: Literature review and meta-analysis

OBJECTIVE

To determine the diagnostic value of acute infarcts in multiple cerebral circulations (AIMCC) on MRI diffusion-weighted imaging (DWI) for cardioembolism (CE) stroke subtype in adult patients hospitalized with acute ischemic stroke, we conducted a systematic literature review and meta-analysis.

METHODS

MEDLINE was searched via PubMed for articles reporting patients hospitalized with acute ischemic stroke with MRI DWI categorized as AIMCC vs other and use of Trial of Org 10172 in Acute Stroke Treatment (TOAST) Criteria for cardioembolism subtype. Measures of diagnostic accuracy were calculated from the retrieved studies.

RESULTS

Seven eligible articles comprised 5813 patients. Bivariate random effects models estimated sensitivity 0.19 (95% CI, 0.13 to 0.27), specificity 0.89 (0.86 to 0.91), positive predictive value 0.37 (0.30 to 0.45), negative predictive value 0.76 (0.7 to 0.82), positive likelihood ratio 1.70 (1.13 to 2.57) and negative likelihood ratio 0.91 (0.83 to 1).

INTERPRETATION

The pattern of AIMCC on DWI is of limited diagnostic value. It is not sufficiently accurate to exclude cardiac pathology by a negative test nor does a positive test indicate a major increase in the probability of identifying a potential cardioembolic source.

Acute Unilateral Audiovestibulopathy due to Embolic Labyrinthine Infarction

Introduction

Labyrinthine infarction is a cause of acute audiovestibulopathy, but can be diagnosed only in association with other infarctions involving the brainstem or cerebellar areas supplied by the anterior inferior cerebellar artery (AICA) since current imaging techniques cannot visualize an infarction confined to the labyrinth. This case series aimed to establish embolic labyrinthine infarction as a mechanism of isolated acute audiovestibulopathy.

Methods

We analyzed clinical features, imaging findings, and mechanisms of embolism in 10 patients (8 men, age range: 38–76) who had developed acute audiovestibulopathy in association with an obvious source of embolism and concurrent acute embolic infarctions in the non-anterior inferior cerebellar artery territories. The presence of audiovestibulopathy was defined when bedside or laboratory evaluation documented unilateral vestibular (head-impulse tests or caloric tests) or auditory loss (audiometry).

Results

Six patients showed combined audiovestibulopathy while three had isolated vestibulopathy. One patient presented isolated hearing loss. Audiovestibular findings were the only abnormalities observed in nine patients. In all patients, MRIs documented single or multiple infarctions in the cerebellum (n = 5) or cerebral hemispheres (n = 5). Especially three patients showed single or scattered foci of tiny acute infarctions only in the cerebral hemispheres. Cardiac sources of embolism were found in eight, and artery-to-artery embolism was presumed in two patients.

Conclusion

Selective embolism to the labyrinth may be considered in patients with acute unilateral audiovestibulopathy and concurrent acute infarctions in the non-AICA territories.

Significance of Multiple Acute Ischemic Lesions on Initial Diffusion-weighted Imaging in Stroke Patients and Relation of Toast Classification

Background

It is important to know whether or not the stroke risk factors and etiologies of patients with multiple acute infarcts are different to those of patients with a single acute infarct.

Aim

The frequency of multiple acute infarct was investigated in ischemic stroke patients and a comparison was made of the characteristics of stroke patients with and without multiple acute infarct.

Patients and Methods

We reviewed the clinical records of 988 ischemic stroke patients who were admitted within 1 week of the onset of stroke and diffusion-weighted imaging (DWI) was performed on first presentation. The clinical characteristics, laboratory, and imaging results were noted from the patient records. According to the DWI findings, the patients were separated into three groups as those with a single acute infarct in a single vascular territory (SI group), those with multiple acute infarcts in a single vascular territory (SMI group) and those with multiple acute infarcts in multiple vascular (MMI group) territories. The frequency of multiple acute infarcts was investigated, and a comparison was made of the characteristics of stroke patients with and without multiple acute infarcts.

Results

The SMI group included 119 (12%) patients and the MMI group 126 (12.8%). The most common mechanisms of multiple acute infarcts are large artery atherosclerosis and cardiac origin emboli. Moreover, the risk factors most determined were hypertension, diabetes mellitus, and hyperlipidemia in the MMI group.

Conclusion

No difference was determined between the groups in respect of stroke etiology and risk factors.

Acute cerebral infarcts in multiple arterial territories associated with cardioembolism

OBJECTIVES

It is generally believed that cardioembolism is the main cause of multiple acute cerebral infarcts (MACI). However, there are surprisingly few DWI studies and results are conflicting. Based on a large prospective study we hypothesized that MACI are associated with cardioembolism.

MATERIALS AND METHODS

We studied 2697 patients with acute cerebral infarcts between February 2006 and October 2013 who were prospectively registered in The Bergen NORSTROKE Registry. Among them, 2220 (82.3%) patients underwent magnetic resonance imaging (MRI) and 2125 (96%) of these 2220 patients had DWI lesions. Only patients with DWI lesions were included. MACI were defined as at least two DWI lesions in at least two different arterial territories.

RESULTS

MACI were detected in 187/2125 (8.8%) patients with DWI lesions. MACI patients were older and more often females. MACI were associated with cardioembolism (P = 0.042), especially atrial fibrillation (P = 0.002). Other associations were symptomatic internal carotid artery (ICA) stenosis (P = 0.014), asymptomatic ICA stenosis (P = 0.036), and higher NIHSS score on admission (P < 0.001). Among patients with no cardioembolism, 34 (35%) with MACI had symptomatic ICA stenosis versus 268 (25.0%) with non-MACI (P = 0.037); 20 (20%) with MACI had asymptomatic ICA stenosis versus 134 (13%) with non-MACI (P = 0.031). In the logistic regression analysis, cardiac embolism and symptomatic ICA stenosis were independently associated with MACI.

CONCLUSIONS

Acute cerebral infarcts in more than one arterial territory occur among almost 10% of the patients and are associated with cardioembolism.

Association of multiple infarctions and ICAS with outcomes of minor stroke and TIA

OBJECTIVE

To estimate the association of different patterns of infarction and intracranial arterial stenosis (ICAS) with the prognosis of acute minor ischemic stroke and TIA.

METHODS

We derived data from the Clopidogrel in High-risk Patients with Acute Nondisabling Cerebrovascular Events (CHANCE) trial. A total of 1,089 patients from 45 of 114 participating sites of the trial undergoing baseline MRI/angiography were included in this subgroup analysis. Patterns of infarction and ICAS were recorded for each individual. The primary efficacy outcome was an ischemic stroke at the 90-day follow-up. We assessed the associations between imaging patterns and prognosis of patients using multivariable Cox regression models.

RESULTS

Among the 1,089 patients included in this subgroup analysis, 93 (8.5%) patients had a recurrent ischemic stroke at 90 days. Compared with those without infarction or ICAS, patients with single infarction with ICAS (11.9% vs 1.3%, hazard ratio [HR] 6.25, 95% confidence intervals [CIs] 1.40-27.86, p = 0.02) and single infarction without ICAS (6.8% vs 1.3%, HR 4.65, 95% CI 1.05-20.64, p = 0.04) were all associated with an increased risk of ischemic stroke at 90 days. Patients with both multiple infarctions and ICAS were associated with approximately 13-fold risk of ischemic stroke at 90 days (18.0% vs 1.3%, HR 13.14, 95% CI 2.96-58.36, p < 0.001).

CONCLUSIONS

The presence of multiple infarctions and ICAS were both associated with an increased risk of 90-day ischemic stroke in patients with minor stroke or TIA, while the presence of both imaging features had a combined effect.

CLINICALTRIALSGOV IDENTIFIER

NCT00979589.

Time patterns in multiple acute cerebral infarcts

Background

Multiple acute cerebral infarcts in different arterial territories may be caused by several emboli concurrently or successively.

Aim and/or hypothesis

We hypothesized that the time from stroke onset to magnetic resonance imaging may shed light on underlying mechanisms of multiple acute cerebral infarcts.

Methods

This is a prospective observational cohort study involving 2697 ischemic stroke patients conducted at Haukeland University Hospital between February 2006 and October 2013. Only patients with diffusion-weighted imaging lesions in more than one arterial territory (left or right anterior circulation or posterior circulation) were included. The time from stroke onset to magnetic resonance imaging was registered and correlated with the etiology of multiple acute cerebral infarcts in each patient.

Results

We reviewed 2697 consecutive patients and 2220 (82%) underwent magnetic resonance imaging. Among these 2125 (96%) had diffusion-weighted imaging lesions. We found 187 multiple acute cerebral infarct patients who were then included in the study. There was positive correlation (0.20; p < .001) between time to magnetic resonance imaging and frequency of multiple acute cerebral infarcts caused by internal carotid stenosis. There was no correlation (−.02) between time to magnetic resonance imaging and frequency of multiple acute cerebral infarcts caused by cardiogenic embolism.

Conclusions

Multiple acute cerebral infarcts associated with cardiogenic embolism seem to happen concurrently as a shower of emboli whereas multiple acute cerebral infarcts associated with internal carotid artery stenosis seem to occur successively separated by hours or days.

Magnetic resonance imaging in acute ischemic stroke treatment

Although intravenous administration of tissue plasminogen activator is the only proven treatment after acute ischemic stroke, there is always a concern of hemorrhagic risk after thrombolysis. Therefore, selection of patients with potential benefits in overcoming potential harms of thrombolysis is of great importance. Despite the practical issues in using magnetic resonance imaging (MRI) for acute stroke treatment, multimodal MRI can provide useful information for accurate diagnosis of stroke, evaluation of the risks and benefits of thrombolysis, and prediction of outcomes. For example, the high sensitivity and specificity of diffusion-weighted image (DWI) can help distinguish acute ischemic stroke from stroke-mimics. Additionally, the lesion mismatch between perfusion-weighted image (PWI) and DWI is thought to represent potential salvageable tissue by reperfusion therapy. However, the optimal threshold to discriminate between benign oligemic areas and the penumbra is still debatable. Signal changes of fluid-attenuated inversion recovery image within DWI lesions may be a surrogate marker for ischemic lesion age and might indicate risks of hemorrhage after thrombolysis. Clot sign on gradient echo image may reflect the nature of clot, and their location, length and morphology may provide predictive information on recanalization by reperfusion therapy. However, previous clinical trials which solely or mainly relied on perfusion-diffusion mismatch for patient selection, failed to show benefits of MRI-based thrombolysis. Therefore, understanding the clinical implication of various useful MRI findings and comprehensively incorporating those variables into therapeutic decision-making may be a more reasonable approach for expanding the indication of acute stroke thrombolysis.

Ischemic stroke in patients with cancer: is it different from usual strokes?

BACKGROUND

It remains unclear whether the characteristics of ischemic stroke in patients with cancer (ISC) differ from usual ischemic strokes (non-ISC). Although a small number of studies have been conducted to characterize ISC, the status of cancer has rarely been considered seriously.

AIMS

We aimed to investigate the features of ISC according to the status of cancer, and compare their characteristics with those of non-ISC.

METHODS

We assessed and classified 204 ISC patients into two groups: 104 with active (ISC-active) and 100 with inactive (ISC-inactive) cancer. For each ISC patient, two age- and gender-matched ischemic stroke patients without history of cancer were selected as non-ISC control subjects. We compared the clinical/laboratory data, stroke mechanisms, and diffusion weighted imaging (DWI) lesion patterns between ISC-active and non-ISC patients, and between ISC-inactive and non-ISC patients.

RESULTS

ISC-active patients demonstrated higher C-reactive protein (CRP) and D-dimer, more frequent cryptogenic stroke and patterns of multiple DWI lesions (in bilateral anterior or in anterior and posterior circulations), and less prevalent conventional risk factors than non-ISC patients, while ISC-inactive patients revealed no such marked differences. Among ISC-active patients, both elevated CRP and D-dimer levels were associated with cryptogenic mechanism and multiple lesion patterns. Furthermore, ISC-active patients with cryptogenic strokes tended to have multiple lesion patterns and metastasis.

CONCLUSIONS

ISC-active, but not ISC-inactive, is distinct in terms of risk factors, stroke mechanisms, and lesion patterns. Chronic inflammation and an activated coagulation system may contribute to the pathogenic mechanism of strokes, the extent of each depending on the activity and severity of cancer.

Acute simultaneous multiple lacunar infarcts: a severe disease entity in small artery disease

BACKGROUND

We hypothesized that acute simultaneous multiple lacunar infarcts (sMLI) may have different clinico-radiological characteristics compared to acute single lacunar infarcts (SLI).

METHODS

We retrospectively reviewed stroke patients with sMLI or SLI in a consecutively collected stroke registry with a predefined long-term clinical follow-up. Clinical characteristics, including vascular risk factors, rheological profiles, premorbid functional status, and clinical outcome were evaluated. In addition, radiological characteristics, including white matter ischemic changes, previous lacunes, microbleeds, and concomitant intra- or extracranial arterial stenosis were evaluated.

RESULTS

Of the 548 acute ischemic stroke patients, sMLI was found in 23 (13.5%) and SLI in 148 (86.5%). There was no difference in vascular risk factors and rheological profiles between the two groups, except for advanced age and more frequent previous history of stroke in the sMLI group. The sMLI group also showed more previous lacunes (p < 0.001) and microbleeds (p < 0.001). A cardioembolic or atherothrombotic stroke mechanism was rare in both groups. Recurrent strokes were more frequent in the sMLI group.

CONCLUSIONS

The main pathophysiology of sMLI may be small artery disease. However, clinico-radiological characteristics suggest that sMLI may be a more severe entity of small artery disease compared to SLI.

Multiple subcortical acute ischemic lesions reflect small vessel disease rather than cardiogenic embolism

Multiple acute ischemic lesions in different hemispheres or vascular territories are mainly considered to be of proximal embolic origin. However, despite careful diagnostic work-up, the etiological classification often stays undetermined. We propose that multiple acute ischemic lesions can sometimes be a phenomenon observed in small vessel disease (SVD). From a prospectively collected database of more than 7,000 stroke patients, 173 patients with acute bihemispheric infarction were identified. We analyzed those subjects with multiple small (< 15 mm Ø) subcortical acute ischemic lesions on diffusion-weighted MRI (DWI) and concomitant severe small vessel disease (Fazekas grades II-III) without a proximal embolic source as evaluated by cardiological investigations. Twenty patients (mean age 66 ± 12 years, 12 men) with a mean number of 2.95 ± 1.24 acute lesions on DWI (range of 2-7 lesions per patient) were identified (n = 5 Fazekas II°, n = 15 Fazekas III°). Most of the lesions were located in typical areas of lacunar infarction. The mean NIHSS score on admission was 2.95 ± 2.0 (range 0-8). Multiple acute ischemic lesions in different vascular territories might not always be of proximal cardiovascular embolic origin. Simultaneous small subcortical ischemic lesions may reflect remote ischemia due to small vessel disease reflecting simultaneous hemorheological dysfunction.

Differentiation between spontaneous echocardiographic contrast and left atrial appendage thrombus in patients with suspected embolic stroke using two-phase multidetector computed tomography

The detection of a thrombus at the left atrial appendage (LAA) is an important step for management in a patient with a suspected embolic infarction. However, spontaneous echocardiographic contrast (SEC), which can mimic thrombus, can confuse clinicians in many cases. We examined electrocardiographic-gated 64-slice multidetector computed tomography with a 2-phase scan and transesophageal echocardiography in 314 patients with suspected embolic stroke. The transesophageal echocardiographic findings were classified using a 5-grade scale and the multidetector computed tomographic findings were categorized as no filling defect, an early filling defect (a filling defect seen on early-phase images without considering the late-phase images), and a persistent filling defect (a filling defect seen on added late-phase images, as well as on early-phase images). For quantitative analysis, the ratio of Hounsfield units in the LAA to the ascending aorta (AA) was calculated for each early-phase and late-phase image (LAA/AA(L)). Using transesophageal echocardiography as the reference standard, for no filling defect seen on early-phase images, the presence of a thrombus, including severe SEC, could be ruled out with 100% sensitivity and a 100% negative predictive value. When considering the addition of late-phase images, all persistent filling defects had resulted from the presence of a thrombus and severe SEC. However, using the optimal cutoff value of 0.5 for the LAA/AA(L) ratio, thrombi could be distinguished from severe SEC where all thrombi had a LAA/AA(L) ratio < 0.5. In conclusion, our findings suggest that 2-phase multidector computed tomography is useful for the detection and differentiation of a thrombus from SEC at the LAA in patients with suspected embolic stroke.

Inflammatory and Hemostatic Biomarkers Associated With Early Recurrent Ischemic Lesions in Acute Ischemic Stroke

Background and Purpose— Early recurrent ischemic lesions (ERILs) on diffusion-weighted imaging after acute ischemic stroke have been suggested as a potential marker of early recurrent stroke. We hypothesized that biomarkers of inflammation or coagulation may be associated with the pathogenesis of ERILs and sought to investigate whether these biomarkers provide prognostic information on the risk of development of ERILs independently of clinical and imaging variables.

Methods— This prospective study enrolled 153 consecutive patients with acute ischemic stroke who underwent diffusion-weighted imaging within 24 hours and subsequently at 5 days after onset and whose plasma or serum for biomarkers (C-reactive protein, fibrinogen, d -dimer, tissue plasminogen activator, and plasminogen activator inhibitor-1) were collected within 24 hours of onset. Those receiving thrombolysis or interventional therapy were excluded. ERILs were defined as new ischemic lesions on 5-day diffusion-weighted imaging separate from the index stroke lesions, which were not accompanied by subsequent recanalization.

Results— ERILs were observed in 37 patients (24.2%). In univariate analysis, shorter time from onset to initial MRI ( P =0.013), initial acute multiple infarcts ( P <0.001), initial larger infarct volume ( P =0.005), stroke subtype ( P <0.001), elevated d -dimer ( P =0.028), and anticoagulation after admission ( P =0.001) were associated with ERILs. In multivariate analysis, initial acute multiple infarcts (OR, 16.60; 95% CI, 5.73 to 48.08), large artery atherosclerosis (OR, 4.62; 95% CI, 1.51 to 14.11), and log d -dimer (OR, 3.20; 95% CI, 1.14 to 9.00) remained independent predictors of ERILs.

Conclusion— These data suggest that elevated d -dimer level reflecting increase of thrombin generation and fibrin turnover may be an independent factor predicting ERILs.