Significance of acute multiple infarcts in multiple cerebral circulations on initial diffusion weighted imaging in stroke patients

Seasonal variability of lesions distribution in acute ischemic stroke: A retrospective study

Seasonal variability could have an impact on the incidence and outcome of stroke. However, little is known about the correlation between seasonal variability and location of acute cerebral infarction. This study aimed to explore the relationship between onset season and the lesions distribution of acute ischemic stroke (AIS). We retrospectively analysis data from 1488 AIS patients admitted to the Second Hospital of Tianjin Medical University from 2018 to 2022. All subjects completed head magnetic resonance imaging examination (MRI) and were divided into four groups according to the onset seasons. The lesions distribution of AIS was evaluated for anterior/posterior/double circulation infarction (DCI), unilateral/bilateral infarctions, and single/multiple cerebral infarctions based on MRI. Logistic regression models were employed to assess the association of season with lesions distribution of AIS. Subgroup analysis was performed in different stroke subtypes. Of 1488 patients, 387 (26.0%) AIS occurred in spring, 425 (28.6%) in summer, 331 (22.2%) in autumn and 345 (23.2%) in winter. Multivariate logistic regression demonstrated that the winter group had 2.15 times (95% CI:1.44-3.21) risk of multiple infarctions, 2.69 times (95% CI:1.80-4.02) of bilateral infarctions and 1.54 times (95% CI:1.05-2.26) of DCI compared with summer group, respectively. Subgroup analysis showed an increased risk of multiple (p < 0.01) or bilateral infarctions (p < 0.01) in small-artery occlusion (SAO) subtype, and higher risk of bilateral infarctions (p < 0.01) or DCI (p < 0.05) in large artery atherosclerosis (LAA) subtype during winter. No significant associations of season with lesions distribution in cardioembolism subtype. Our study highlighted a prominent seasonal variability in the lesions distribution of AIS, particularly in LAA and SAO subtypes. The findings could help to formulating meteorological risk warning strategies for different subtypes.

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.

Diagnostic Evaluation of Stroke Etiology

OBJECTIVE

Precise therapies require precise diagnoses. This article provides an evidence-based approach to confirming the diagnosis of ischemic stroke, characterizing comorbidities that provide insights into the pathophysiologic mechanisms of stroke, and identifying targets for treatment to optimize the prevention of recurrent stroke.

LATEST DEVELOPMENTS

Identifying the presence of patent foramen ovale, intermittent atrial fibrillation, and unstable plaque is now routinely included in an increasingly nuanced workup in patients with stroke, even as ongoing trials seek to clarify the best approaches for treating these and other comorbidities. Multicenter trials have demonstrated the therapeutic utility of patent foramen ovale closure in select patients younger than age 60 years. Insertable cardiac monitors detect atrial fibrillation lasting more than 30 seconds in about one in ten patients monitored for 12 months following a stroke. MRI of carotid plaque can detect unstable plaque at risk of being a source of cerebral embolism.

ESSENTIAL POINTS

To optimize the prevention of recurrent stroke, it is important to consider pathologies of intracranial and extracranial blood vessels and of cardiac structure and rhythm as well as other inherited or systemic causes of stroke. Some aspects of the stroke workup should be done routinely, while other components will depend on the clinical circumstances and preliminary testing results.

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.

Secondary stroke prevention in patients with patent foramen ovale

PURPOSE OF REVIEW

Although a patent foramen ovale (PFO) is an established risk factor for cryptogenic ischemic stroke, strategies for secondary prevention remain controversial. Increasing evidence over the past decade from well designed clinical trials supports transcatheter PFO closure for selected patients whose stroke was likely attributable to the PFO. However, patient selection using imaging findings, clinical scoring systems, and in some cases, thrombophilia testing, is crucial for determining patients most likely to benefit from closure, anticoagulation, or antiplatelet therapy.

RECENT FINDINGS

Recent studies have found that patients with a high Risk of Paradoxical Embolism (RoPE) score and those with a thrombophilia benefit more from closure than medical therapy (including antiplatelet or anticoagulant therapy) alone. Meta-analyses have demonstrated an increased short-term risk of atrial fibrillation in closure patients, and that residual shunt after closure predicts stroke recurrence. Last, recent data have been inconclusive as to whether patients receiving medical therapy only benefit more from anticoagulation or antiplatelet therapy, so this remains an area of controversy.

SUMMARY

Transcatheter PFO closure is an evidence-based, guideline-supported therapy for secondary stroke prevention in patients with a PFO and cryptogenic stroke. However, proper patient selection is critical to achieve benefit, and recent studies have helped clarify those patients most likely to benefit from closure.

Clinical manifestation of acute cerebral infarcts in multiple arterial territories

OBJECTIVES

We aimed to assess frequencies and radiological aspects of single- and multiterritory clinical manifestation among patients with acute cerebral infarcts in multiple arterial territories (MACI).

MATERIALS & METHODS

We retrospectively reviewed admission records and diffusion-weighted magnetic resonance imaging of patients with MACI admitted to our stroke unit between 2006 and 2017. MACI was defined as acute cerebral ischemic lesions in at least two out of three arterial cerebral territories, that is, the left anterior, right anterior and the bilateral posterior territory. Patients with single- and multiterritory clinical manifestation were then compared for topographical distribution of the ischemic lesions, the number of ischemic lesions, and The Oxfordshire Community Stroke Project classification.

RESULTS

Out of 311 patients with MACI, 222 (71.4%) presented with single-territory clinical manifestation. Involvement of the left hemisphere (OR = 0.37, 95% CI 0.16-0.82), less than five ischemic lesions (OR = 0.58, 95% CI 0.35-0.97), and partial anterior circulation infarct clinical stroke syndrome (OR = 0.57, 95% CI 0.34-0.97) were associated with single-territory clinical manifestation. Involvement of all three territories (OR = 2.58, 95% = 1.48-4.50), more than 10 ischemic lesions (OR = 2.30, 95% CI 1.32-4.01) and total anterior circulation infarct clinical stroke syndrome (OR = 3.31, 95% CI 1.39-7.86) were associated with multiterritory clinical manifestation.

CONCLUSION

Most patients with MACI present with single-territory clinical manifestation on admission. Diffusion-weighted magnetic resonance imaging is therefore necessary for a definite diagnosis.

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.

Five-Year Prognosis After TIA or Minor Ischemic Stroke in Asian and Non-Asian Populations

OBJECTIVE

To determine long-term vascular outcomes of Asian patients who experienced TIA or minor ischemic stroke and to compare the outcomes of Asian patients with those of non-Asian patients, in the context of modern guideline-based prevention strategies.

METHODS

This is a subanalysis of the TIAregistry.org project, in which 3,847 patients (882 from Asian and 2,965 from non-Asian countries) with a recent TIA or minor ischemic stroke were assessed and treated by specialists at 42 dedicated units from 14 countries and followed for 5 years. The primary outcome was a composite of cardiovascular death, nonfatal stroke, and nonfatal acute coronary syndrome.

RESULTS

No differences were observed in the 5-year risk of the primary outcome (14.0% vs 11.7%; hazard ratio [HR], 1.10; 95% confidence interval [CI], 0.88-1.37; p = 0.41) and stroke (10.7% vs 8.5%; HR, 1.17; 95% CI, 0.90-1.51; p = 0.24) between Asian and non-Asian patients. Asian participants were at higher risk of intracranial hemorrhage (1.8% vs 0.8%; HR, 2.23; 95% CI, 1.09-4.57; p = 0.029). Multivariable analysis showed that the presence of multiple acute infarctions on initial brain imaging was an independent predictor of primary outcome and modified Rankin Scale score of >1 in both Asian (HR, 1.91; 95% CI, 1.11-3.29; p = 0.020) and non-Asian (HR, 1.39; 95% CI, 1.02-1.90; p = 0.037) patients.

CONCLUSION

The long-term risk of vascular events in Asian patients was as low as that in non-Asian patients, while Asian participants had a 2.2-fold higher intracranial hemorrhage risk. Multiple acute infarctions were independently associated with future disability in both groups.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that among people who experienced TIA or minor stroke, Asian patients have a similar 5-year risk of cardiovascular death, stroke, and acute coronary syndrome as non-Asian patients.

Short-Term Outcome and In-Hospital Complications After Acute Cerebral Infarcts in Multiple Arterial Territories

Background and Purpose—

Patients with acute cerebral infarcts in multiple arterial territories (MACI) represent a substantial portion of the stroke population. There are no data on short-term outcome and in-hospital complications in patients with MACI. We compared patients with MACI with patients having acute cerebral infarct(s) in a single arterial territory.

Methods—

We analyzed 3343 patients with diffusion-weighted imaging-confirmed acute cerebral infarcts. MACI was defined as at least 2 acute cerebral ischemic lesions in at least 2 arterial cerebral territories. Patients with MACI were compared with patients with acute cerebral infarct(s) in a single arterial territory for relevant in-hospital complications and short-term outcome, namely National Institutes of Health Stroke Scale and modified Rankin Scale at day 7 after admission or at discharge when earlier.

Results—

A total of 311 patients (9.3%) met the definition of MACI. Both median National Institutes of Health Stroke Scale (2 [1–7] versus 1 [0–4]) and modified Rankin Scale (3 [1–4] versus 2 [1–3]) were higher in patients with MACI. MACI was independently associated with higher National Institutes of Health Stroke Scale and modified Rankin Scale. Deep venous thrombosis, myocardial infarction, and any complications were more frequent in patients with MACI.

Conclusions—

In-hospital complications were more frequent in patients with MACI, which may adversely affect short-term clinical and functional outcome. Closer follow-up of patients with MACI during hospitalization may prevent such events and negative progression.

Causes of Acute Stroke: A Patterned Approach

Acute stroke is a leading cause of morbidity and mortality in the United States. Acute ischemic strokes have been classified according to The Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification system, and this system aids in proper management. Nearly every patient who presents to a hospital with acute stroke symptoms has some form of emergent imaging. As such, imaging plays an important role in early diagnosis and management. This article reviews the imaging patterns of acute strokes, and how the infarct pattern and imaging characteristics can suggest an underlying cause.

Ischemic lesions in all territories as a marker of malignant hypercoagulability

Hypercoagulability due to cancer is an overlooked cause of stroke and presents with a typical MRI pattern, that is small embolic strokes in several vascular territories.

The Relationship between Diffusion-Weighted Magnetic Resonance Imaging Lesions and 24-Hour Rhythm Holter Findings in Patients with Cryptogenic Stroke

BACKGROUND AND OBJECTIVES

Cranial magnetic resonance imaging findings of patients considered to be cryptogenic stroke may be useful in determining the clinical and prognostic significance of arrhythmias, such as atrial premature beats and atrial run attacks, that are frequently encountered in rhythm Holter analysis. This study was conducted to investigate the relationship between short atrial runs and frequent premature atrial contractions detected in Holter monitors and infarct distributions in cranial magnetic resonance imaging of patients diagnosed with cryptogenic stroke.

MATERIALS AND METHODS

We enrolled the patients with acute ischemic stroke whose etiology were undetermined. We divided the patients in two groups according to diffusion-weighted magnetic resonance imaging as single or multiple vascular territory acute infarcts. The demographic, clinical, laboratory, echocardiographic, and rhythm Holter analyses were compared.

RESULTS

The study investigated 106 patients diagnosed with cryptogenic stroke. Acute cerebral infarctions were detected in 31% of the investigated patients in multiple territories and in 69% in a single territory. In multivariate logistic regression analysis, the total premature atrial contraction count (OR = 1.002, 95% CI: 1.001⁻1.004, p = 0.001) and short atrial run count (OR = 1.086, 95% CI: 1.021⁻1.155, p = 0.008) were found as independent variables that could distinguish between infarctions in a single or in multiple vascular territories.

CONCLUSIONS

Rhythm Holter monitoring of patients with infarcts detected in multiple vascular territories showed significantly higher premature atrial contractions and short atrial run attacks. More effort should be devoted to the identification of cardioembolic etiology in cryptogenic stroke patients with concurrent acute infarcts in the multiple vascular territories of the brain.

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.

Stroke subtype classification by geometrical descriptors of lesion shape

Background and purpose

Inference of etiology from lesion pattern in acute magnetic resonance imaging is valuable for management and prognosis of acute stroke patients. This study aims to assess the value of three-dimensional geometrical lesion-shape descriptors for stroke-subtype classification, specifically regarding stroke of cardioembolic origin.

Methods

Stroke Etiology was classified according to ASCOD in retrospectively selected patients with acute stroke. Lesions were segmented on diffusion-weighed datasets, and descriptors of lesion shape quantified: surface area, sphericity, bounding box volume, and ratio between bounding box and lesion volume. Morphological measures were compared between stroke subtypes classified by ASCOD and between patients with embolic stroke of cardiac and non-cardiac source.

Results

150 patients (mean age 77 years; 95% CI, 65–80 years; median NIHSS 6, range 0–22) were included. Group comparison of lesion shape measures demonstrated that lesions caused by small-vessel disease were smaller and more spherical compared to other stroke subtypes. No significant differences of morphological measures were detected between patients with cardioembolic and non-cardioembolic stroke.

Conclusion

Stroke lesions caused by small vessel disease can be distinguished from other stroke lesions based on distinctive morphological properties. However, within the group of embolic strokes, etiology could not be inferred from the morphology measures studied in our analysis.

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.

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.

The natural defense system and the normative self model

Infectious agents are not the only agressors, and the immune system is not the sole defender of the organism. In an enlarged perspective, the ‘normative self model’ postulates that a ‘natural defense system’ protects man and other complex organisms against the environmental and internal hazards of life, including infections and cancers. It involves multiple error detection and correction mechanisms that confer robustness to the body at all levels of its organization. According to the model, the self relies on a set of physiological norms, and NONself (meaning : Non Obedient to the Norms of the self) is anything ‘off-norms’. The natural defense system comprises a set of ‘civil defenses’ (to which all cells in organs and tissues contribute), and a ‘professional army ‘, made of a smaller set of mobile cells. Mobile and non mobile cells differ in their tuning abilities. Tuning extends the recognition capabilities of NONself by the mobile cells, which increase their defensive function. To prevent them to drift, which would compromise self/NONself discrimination, the more plastic mobile cells need to periodically refer to the more stable non mobile cells to keep within physiological standards.

Frequency and predictors of acute ischaemic lesions on brain magnetic resonance imaging in young patients with a clinical diagnosis of transient ischaemic attack

BACKGROUND AND PURPOSE

Acute lesions in patients with transient ischaemic attack (TIA) are important as they are associated with increased risk for recurrence. Characteristics associated with acute lesions in young TIA patients were therefore investigated.

METHODS

The sifap1 study prospectively recruited a multinational European cohort (n = 5023) of patients aged 18-55 years with acute cerebrovascular event. The detection of acute ischaemic lesions was based on diffusion-weighted imaging (DWI). The frequency of DWI lesions was assessed in 829 TIA patients who met the criteria of symptom duration <24 h and their association with demographic, clinical and imaging variables was analysed.

RESULTS

The median age was 46 years (interquartile range 40-51 years); 45% of the patients were female. In 121 patients (15%) ≥1 acute DWI lesion was detected. In 92 patients, DWI lesions were found in the anterior circulation, mostly located in cortical-subcortical areas (n = 63). Factors associated with DWI lesions in multiple regression analysis were left hemispheric presenting symptoms [odds ratio (OR) 1.92, 95% confidence interval (CI) 1.27-2.91], dysarthria (OR 2.17, 95% CI 1.38-3.43) and old brain infarctions on MRI (territories of the middle and posterior cerebral artery: OR 2.43, 95% CI 1.42-4.15; OR 2.41, 95% CI 1.02-5.69, respectively).

CONCLUSIONS

In young patients with a clinical TIA 15% demonstrated acute DWI lesions on brain MRI, with an event pattern highly suggestive of an embolic origin. Except for the association with previous infarctions there was no clear clinical predictor for acute ischaemic lesions, which indicates the need to obtain MRI in young individuals with TIA.