White matter medullary infarcts: acute subcortical infarction in the centrum ovale

Long insular artery damage might be a key sign for predicting functional prognosis of putaminal hemorrhage

OBJECTIVE

Although the putamen is the most common area of spontaneous intracerebral hemorrhage, previous reports about the effects of surgery are limited. We sometimes experience a poor prognosis in patients in whom there is no damage to the internal capsule, but with injury in the long insular artery (LIA) region. The purpose of this study was to confirm the relationship between LIA damage and patient prognosis following surgery for putaminal hemorrhage.

METHODS

We retrospectively collected data of 287 surgical cases who presented with putaminal hemorrhage between January 2004 and March 2022. Among them, we chose patients without initial damage to the posterior limb of the internal capsule, and divided these patients into two groups, those without (Group A) and with (Group B) final damage in the LIA region. We compared positivity rates of final manual muscle test (MMT) scores≥3 and related factors.

RESULTS

Sixty-three of the 287 patients were included in this study. Of them, 11 cases in Group A were positive for MMT scores≥3 (68.8%) and 9 cases (19.1%) in Group B had MMT scores≥3 seven days after surgery. Group A thus had a significantly higher rate of MMT scores≥3 than group B (p=0.00).

CONCLUSION

In patients without initial damage to the internal capsule, LIA injury might be a key sign for predicting the functional prognosis of putaminal hemorrhage.

Associations between cerebral blood flow and progression of white matter hyperintensity in community-dwelling adults: a longitudinal cohort study

Background

White matter hyperintensity (WMH) is prevalent in elderly populations. Ischemia is characterized by a decline in cerebral blood flow (CBF) and may play a key role in the pathogenesis of WMH. However, the association between CBF reduction and WMH progression remains controversial. This study aimed to investigate the association between CBF and the progression of WMH at a 2-year follow-up of community-based, asymptomatic adults in a longitudinal cohort study across the lifespan.

Methods

Asymptomatic adults who participated in a community-based study were recruited and underwent brain structural and perfusion magnetic resonance imaging (MRI) at baseline and at a 2-year follow-up visit. The CBF was measured on pseudo-continuous arterial spin-labeling (pCASL) MRI. The WMH was evaluated on T2-weighted fluid-attenuated inversion recovery (T2-FLAIR) images. Tissue segmentation was conducted on T1-weighted (T1W) images to derive binary masks of gray matter and normal-appearing white matter. Linear mixed effect models were conducted to analyze the cross-sectional and longitudinal associations between CBF and WMH.

Results

A total of 229 adults (mean age 57.3±12.6 years; 94 males) were enrolled at baseline, among whom 84 participants (mean age 54.1±11.9 years; 41 males) completed a follow-up visit with a mean time interval of 2.77±0.44 years. At baseline, there was a decreasing trend in gray matter (GM) CBF with an increase of WMH burden (P=0.063), but this association was attenuated after adjusting for age (P=0.362). In the longitudinal analysis, baseline WMH volume was significantly associated with the reduction of perfusion in GM [coefficient =−1.96, 95% confidence interval (CI): −3.25 to −0.67; P=0.004] and normal appearing white matter (coefficient =−0.99, 95% CI: −1.66 to −0.31; P=0.005) during follow-up. On the contrary, neither baseline CBF in GM (P=0.888) nor normal appearing white matter (P=0.850) was associated with WMH progression. In addition, CBF changes within WMH were significantly associated with both baseline (coefficient =−0.014, 95% CI: −0.025 to −0.003; P=0.017) and progression (coefficient =−1.01, 95% CI: −1.81 to −0.20; P=0.015) of WMH volume.

Conclusions

A WMH burden was not found to be directly associated with cortex perfusion at baseline due to the effects of age on both CBF and WMH. However, baseline WMH volume could predict the reduction of perfusion.

Fundus Changes Evaluated by OCTA in Patients With Cerebral Small Vessel Disease and Their Correlations: A Cross-Sectional Study

Objective

To detect fundus changes in patients with cerebral small vessel disease (CSVD) using optical coherence tomography angiography (OCTA) and to investigate the correlations between CSVD and fundus changes.

Methods

From January 2019 to January 2020, patients diagnosed with CSVD by magnetic resonance imaging (MRI) were enrolled in our study and received fundus examinations using OCTA. CSVD was defined as white matter hyperintensities, enlarged perivascular spaces, lacunes, or microbleeds on MRI. OCTA parameters included foveal avascular zone areas, retinal nerve fiber layer thickness, and capillary densities of the superficial retinal capillary plexuses, deep retinal capillary plexuses, and the radial peripapillary capillary network of the disc. Univariate and multivariate logistic regression analyses were performed to explore the correlation between CSVD and fundus changes.

Results

A total of 115 patients (40% male) were enrolled and analyzed, and the mean age was 65.11 ± 11.23 years. After multivariate logistic regression analysis, the radial peripapillary capillary network density was negatively correlated with severity of deep white matter lesions (OR: 0.909; 95% CI: 0.828-0.998; p = 0.046) and perivascular spaces (OR: 0.881; 95% CI: 0.779-0.995; p = 0.041). Parafoveal vessel densities of the superficial retinal capillary plexuses were independently correlated with lacunes (OR: 0.889; 95% CI: 0.817-0.967; p = 0.006).

Conclusion

OCTA parameters were correlated with CSVD, indicating that OCTA is a potential method for CSVD screening.

Existence and Significance of Internal Border Zone Infarcts with Accessory Lesions Located in the Anteromedial Temporal Lobe

OBJECTIVES

To examine the existence and significance of internal border zone (IBZ) infarcts with accessory lesions in the anteromedial temporal lobe (ATL).

MATERIALS AND METHODS

IBZ infarcts located at the corona radiata were selected based on diffusion-weighted imaging of 2535 consecutive patients with ischemic stroke and the presence of lesions in the ATL was identified. The Mann-Whitney U test, Student t-test, Pearson χ² test, or Fisher exact test was used to analyze differences between the IBZ infarct groups with and without accessory lesions in the ATL.

RESULTS

Thirty-six of 2535 patients (1.4%) had IBZ infarcts. The IBZ group with accessory lesions in the ATL (17 cases, 47.2%) showed a higher portion of occluded middle cerebral arteries than the IBZ group without accessory lesions in the ATL (p = 0.02). The initial National Institutes of Health Stroke Scale score (odds ratio, 2.03; 95% confidence interval, 1.04-3.99;   = 0.039) and progression after admission (odds ratio, 25.43; 95% confidence interval, 2.47-261.99; p = 0.007) were independently associated with poor prognosis in patients with IBZ infarcts. There were no differences in the progression rate and clinical outcomes, regardless of the presence of lesions in the ATL.

CONCLUSIONS

Our study suggests the existence of a distinct type of IBZ infarct characterized by accessory lesions in the ATL, which is associated with different arterial features but has a similar clinical course to IBZ infarcts without accessory lesions in the ATL.

Deep chronic microvascular white matter ischemic change as an independent predictor of acute brain infarction after thoracic aortic replacement

BACKGROUND

Postoperative brain injury is a cause of mortality and morbidity in patients who undergo thoracic aortic replacement. Chronic microvascular white matter ischemic change (WMIC) has been shown to be associated with acute brain infarction in the general population. WMIC has also been shown to be an independent predictor of non-focal neurocognitive changes, generalized seizures, and temporary neurologic dysfunction in patients who undergo thoracic aortic replacement. The aim of this study is to determine if WMIC is a risk factor for acute brain infarction in patients who undergo thoracic aortic replacement.

METHODS

A case-control study of patients who underwent thoracic aortic replacement between 2001 and 2014 were reviewed for neurological changes after surgery and acute brain infarction on postoperative diffusion-weighted imaging (DWI) magnetic resonance imaging (MRI). Patients with neurological changes were matched with control patients who underwent thoracic aortic replacement and had postoperative neurological symptoms without acute brain infarctions. Acute infarction was re-assessed by reviewing DWI sequences on postoperative MRI. WMIC was assessed on FLAIR and T2WI sequences on both preoperative and postoperative MRI. Logistic regression was performed assessing the relationship of WMIC and acute ischemic infarction.

RESULTS

5171 patients underwent thoracic aortic replacement; 179 had postoperative neurological changes, and of those 53 patients had acute brain infarction on postoperative DWI. Patients with deep WMIC were more likely to have acute DWI infarctions after thoracic aortic replacement (P = 0.023).

CONCLUSION

Our matched retrospective case-controlled study shows deep WMIC to be a predictor of acute brain infarction on DWI after thoracic aortic replacement.

Risk Factors and Clinical Manifestations of Juxtacortical Small Lesions: A Neuroimaging Study

Background and objective

White matter hyperintensities can be easily identified by brain imaging. Juxtacortical small lesion (JCSL) is a special type of white matter lesion, defined as no greater than 5 mm in diameter and adjacent to the cerebral cortex in location. We notice lately that JCSLs alone may be associated to various neurological symptoms. Here, we design the present study to determine the risk factors for JCSLs and their clinical manifestations in patients in our neurology clinic.

Methods

206 participants suffered from neurological disorders and completed magnetic resonance imaging (MRI) examinations were divided into two groups: patients with JCSLs and patients without lesions on MRI. Meanwhile, 129 age- and sex-matched healthy volunteers were also recruited. Laboratory examinations and the phenotypes and distributions of the symptoms of the three groups were compared.

Results

The serum levels of apoB and homocysteine (HCY) were independently related to the appearance of JCSLs and HCY level was also associated with the number of JCSLs. Patients with JCSLs might present with headache, insomnia, and/or anxiety/depression, which were related with the anatomical locations of the lesions.

Conclusion

These data suggest that JCSLs are symptomatic and might in result fromarteriole atherosclerosis, which should raise our attention.

Do Lacunar Infarcts Have Different Aetiologies? Risk Factor Profiles of Lacunar Infarcts in Deep White Matter and Basal Ganglia: The Second Manifestations of ARTerial Disease-Magnetic Resonance Study

BACKGROUND

Evidence suggests that lacunar infarcts have different etiologies, possibly related to their anatomical location and vascular territory. We investigated the risk factor profiles of patients with new lacunar infarcts in the basal ganglia and deep white matter.

METHODS

Within the Second Manifestations of ARTerial disease-Magnetic Resonance study, a prospective cohort on brain changes on MRI in patients with symptomatic atherosclerotic disease, 679 patients (57 ± 9 years) had vascular screening and MRI at baseline and after a mean follow-up of 3.9 years. We investigated the association between vascular risk factors at baseline and appearance of new lacunar infarcts in the basal ganglia and deep white matter at follow-up.

RESULTS

New lacunar infarcts appeared in 44 patients in the basal ganglia and in 37 patients in the deep white matter. In multivariable analysis, older age, history of cerebrovascular disease, and baseline white matter hyperintensity (WMH) volume were associated with increased risk of new lacunar infarcts in both locations. Hyperhomocysteinemia was associated with increased risk of lacunar infarcts in the basal ganglia (relative risk [RR] 2.0; 95% CI 1.0-4.2), whereas carotid stenosis >70% (RR 2.5; 95% CI 1.2-5.0), smoking (per 10 pack-year: RR 1.1; 95% CI 1.0-1.3), hypertension (RR 3.4; 95% CI 1.2-9.7), and progression of WMH volume (RR 2.4; 95% CI 1.1-5.2) were associated with increased risk of lacunar infarcts in the deep white matter.

CONCLUSIONS

The different risk factor profiles for new lacunar infarcts in basal ganglia and deep white matter indicate different etiologies. The independent association between progression of WMH and new deep white matter lacunar infarcts suggest a common etiology for these radiological abnormalities.

Brain white matter tracts: functional anatomy and clinical relevance

Diffusion tensor imaging is increasingly available on clinical magnetic resonance scanners and can be acquired in a relatively short time. There has been an explosion of applications in the research field but the use to the practicing radiologist may seem obscure. This paper aims to highlight how diffusion tensor imaging can be used to prompt a dedicated neuroanatomical search for white matter lesions in clinical presentations relating to motor, sensory, language, and visuospatial deficits. The enhanced depiction of white matter tracts in the temporal stem is also highlighted, which is a region of importance in epilepsy surgery planning.

Association of intracranial atherosclerotic stenosis with severity of white matter hyperintensities

BACKGROUND AND PURPOSE

White matter hyperintensities (WMHs) on magnetic resonance imaging (MRI) have been linked to small-vessel disease, but the precise pathogenesis underlying WMHs remains unclear. Studies about an association of WMHs with extracranial atherosclerotic stenosis (ECAS) showed conflicting results and the relationship of WMHs with intracranial atherosclerotic stenosis (ICAS) is uncertain.

METHODS

A cross-sectional study of 679 consecutive Korean patients with acute ischaemic stroke (mean age 67.8 ± 12.6; 395 males) who underwent brain MRI/MR angiography was conducted. Severity of deep WMHs (d-WMHs, n = 560) and periventricular WMHs (p-WMHs, n = 590) was rated separately and compared across three groups: ICAS (n = 318), ECAS (n = 71) and no cerebral atherosclerotic stenosis (NCAS) (n = 290).

RESULTS

The ICAS group showed a higher d-WMH/p-WMH score (1.62 ± 0.85/1.65 ± 0.79) than both the ECAS (1.25 ± 0.87/1.23 ± 0.78) and NCAS (1.19 ± 0.92/1.24 ± 0.81) groups (P < 0.001 for all). Patients with a greater number of ICAS were more likely to have higher scores of d-WMH/p-WMH (P < 0.001 for all). Patients with higher scores of d-WMH/p-WMH had a higher incidence of ICAS (P < 0.001 for all), but not of ECAS or NCAS. In multivariable analysis, a dose-response relationship was observed between the extent of ICAS versus WMHs. Compared with one ICAS lesion, for d-WMHs the odds ratio (OR) = 2.61 [95% confidence interval (CI) 0.95-7.20] for two ICAS lesions and OR = 3.37 (1.10-10.32) for ≥3 ICAS lesions; whilst for p-WMHs (score ≥2) OR = 1.70 (95% CI 0.96-2.98) for two ICAS lesions and OR = 2.02 (1.15-3.55) for ≥3 ICAS lesions.

CONCLUSION

ICAS is independently associated with progressively greater WMH burden. The association of ICAS with WMH severity appears to be stronger than that of ECAS/NCAS in the Korean (Asian) stroke population.

Long insular artery infarction: characteristics of a previously unrecognized entity

BACKGROUND AND PURPOSE

The infarctions arising in the long insular arteries of the M2 segment have been poorly described in the past. The purpose of this study was to investigate the incidence, clinical characteristics, and pathogenesis of long insular artery infarcts.

MATERIALS AND METHODS

Patients with acute isolated infarcts in territories of the long insular arteries and lenticulostriate arteries were retrospectively reviewed. The long insular artery territory was defined as the area above the lenticulostriate artery territory at the level of centrum semiovale. On the coronal section, it lies between the tip of the anterior horn and the top of the superior limb of the insular cleft. Clinical features and prevalence of embolic sources were compared between the 2 groups.

RESULTS

Of 356 consecutive patients with acute ischemic stroke, 8 (2.2%) had a long insular artery infarct (long insular artery group) and 50 (14.0%) had a lenticulostriate artery infarct (lenticulostriate artery group). There were no differences in age, sex, prevalence of risk factors, neurologic deficit, or incidence of lacunar syndromes between these groups. Abrupt onset was more common in the long insular artery than in the lenticulostriate artery group (P = .004). The prevalence of embolic high-risk sources (eg, atrial fibrillation) was not significantly different between these groups, but the combined prevalence of all embolic sources, including moderate-risk sources, was significantly higher in the long insular artery group (P = .048).

CONCLUSIONS

Isolated infarction caused by long insular artery occlusion is not rare. Abrupt onset is more common for long insular artery infarction, and this finding could be attributed to the higher incidence of an embolic etiology as the pathogenesis of infarction.

Significance of increased CIMT with coexisting carotid plaques in cerebral white matter lesions in elders

It is very common that increased carotid intima media thickness (CIMT) and carotid plaque coexist in a single subject in elderly patients with white matter lesions (WMLs). In this study we investigated whether the coexistence of increased CIMT and carotid plaque is more strongly associated with the presence and extent of WMLs than either alone. All patients were classified into 1 of the following 4 groups: without either increased CIMT (I) or carotid plaque (P): I(-)P(-); with only increased CIMT: I(+)P(-); with only carotid plaque: I(-)P(+); and with both increased CIMT and carotid plaque: I(+)P(+). The presence and severity of periventricular WMLs (PWMLs) and deep WMLs (DWMLs) were assessed and the prevalence of MRI findings by the Cochran-Armitage trend test was calculated. The characteristics of subjects showed that the percentages of patients with increased CIMT and carotid plaque in the DWMLs group and the PWMLs group were significantly higher than those without WMLs group. Both DWMLs and PWMLs were strongly associated with age, carotid plaque and CIMT. Furthermore, the Cochran-Armitage trend test indicated that the prevalence of MRI findings of PWMLs and DWMLs increased in the order of I(-)P(-)< I(+)P(-)< I(-)P(+)< I(+)P(+) (P<0.0001). For the patients with DWMLs, the grades of both I(+)P(-) and I(+)P(+) were increased significantly compared to I(-)P(-) (P<0.0025, P<0.05, respectively) without such a difference found in patients with PWMLs. Our results suggested that the coexistence of increased CIMT and carotid plaque is most closely associated with WMLs, and that increased CIMT is associated with the severity of DWMLs, whereas carotid plaque is related to the presence of WMLs.

Differing risk factors and outcomes in ischemic stroke subtypes: focus on lacunar stroke

Lacunar stroke has been a recognized stroke subtype for many years but its pathophysiology remains unknown, so prevention and treatment are suboptimal. Most lacunar strokes result from an intrinsic cerebral small vessel disease, probably part of a systemic disorder. Hypertension, diabetes and other vascular risk factors (but not atrial fibrillation and ipsilateral carotid stenosis) are equally common in lacunar as in large artery atherothromboembolic stroke, which, together with other factors, suggests that the patient’s response to vascular risk factors, not the vascular risk factors per se, determines whether they develop small vessel or large artery stroke. Inflammation and endothelial failure are probably involved in the pathogenesis of lacunar stroke, but their role needs to be clarified. The cerebral venules as well as arterioles are abnormal in this condition. The disorder may not be primarily ischemic; instead, arteriolar thrombosis may be a late-stage phenomenon secondary to chronic arteriolar wall damage resulting from leakage of plasma components across the BBB. Accurate diagnosis of lacunar stroke, avoiding risk factor-based classifications, is required to underpin future research.

Wide variation in definition, detection, and description of lacunar lesions on imaging

BACKGROUND AND PURPOSE

Variation in the definition of lacunar lesions on imaging and difficulties in their detection may be hampering lacunar stroke research. We assessed literature definitions of imaging lacunar lesions and the definitions and detection of lacunar lesions among small-vessel disease researchers.

METHODS

We assessed definitions of imaging lacunar lesion in 50 randomly selected articles from 3 stroke-related journals and an online survey of small-vessel disease researchers. In the literature review, we assessed clinical/imaging definitions of lacunar stroke. In the survey, we assessed lacunar lesion detection, effects of lesion appearance, background white matter lesions, and provision of relevant data.

RESULTS

Among 50 articles, imaging definitions were varied and often limited; size was stated in 21 of 43 (49%) studies of acute and in 9 of 20 (45%) studies of old lesions and site in 18 (42%) and 4 (20%), respectively. Clinical definitions also varied, and images were read mostly by nonradiologists. Among 56 survey respondents, multiple descriptions were used for recent and old, symptomatic and asymptomatic, lesions on imaging. Most agreed on definitions for site (98%) and "old lacunar infarct" (61%) size. Cavitated (vs noncavitated) lesions were usually identified as lacunar lesions; with increasing white matter lesions, however, noncavitated lesions were very unlikely to be identified, even with prior imaging available (7.8%).

CONCLUSIONS

Imaging definitions of lacunar lesions vary widely, in part due to variation in lesion detection and classification. A consensus for imaging definitions of small-vessel disease features would be helpful.

Clinical and radiologic correlations of small and large centrum ovale infarcts

BACKGROUND

Acute centrum ovale (CO) infarction confined to the territory of perforating long medullary arteries is rarely reported. This study was designed to investigate the full spectrum of clinical findings, topography, and pathogenesis of patients with acute CO infarct.

METHODS

A total of 64 patients with CO infarct were recorded. Risk factors such as age, hypertension, diabetes mellitus, hypercholesterolemia, smoking, and cardiopathy were recorded.

RESULTS

The average age of the patients was 64.2 years. There were 46 patients (71.8%) in large-infarct group and 18 patients (28.1%) in small-infarct group. The most frequent risk factor was hypertension (89.1%). Other risk factors included smoking (39%), diabetes mellitus (29.7%), hyperlipidemia (28.1%), transient ischemic attack (15%), carotid stenosis (9%), atrial fibrillation (21%), other potential cardiac source of embolism (39%), and myocardial infarct (4%). The main clinical feature was faciobrachiocrural paralysis associated dysarthria (51.6%). Other clinical characteristics were facial, upper and lower extremity paralysis with sensorial deficits and/or dysarthria (26.6%), hemiparesis including face (12.5%), and either facial and upper or upper and lower extremity paralysis with hemisensorial deficit (9.4%). The baseline Barthel index was found to be less than 50 in 22 patients (34.4%) and greater than 50 in 42 patients (65.6%) for the entire group whereas 72% of patients were independent at discharge.

CONCLUSION

In this article, risk factors, clinical spectrum, and features of CO infarcts were correlated in a large patient group. The majority of CO infarcts were large and had a poorer outcome compared to previous reports.

Lacunar stroke

Lacunar infarcts or small subcortical infarcts result from occlusion of a single penetrating artery and account for one quarter of cerebral infarctions. Patients with a lacunar infarct usually present with a classical lacunar syndrome (pure motor hemiparesis, pure sensory syndrome, sensorimotor stroke, ataxic hemiparesis or dysarthria-clumsy hand) and, less frequently, an atypical lacunar syndrome. Hypertension and diabetes mellitus are major risk factors for lacunar stroke. Lacunar infarcts show a paradoxical clinical course with a favorable prognosis in the short term, characterized by a low early mortality and reduced functional disability on hospital discharge, but with an increased risk of death, stroke recurrence and dementia in the mid- and long term. Asymptomatic progression of small-vessel disease is a typical feature of the lacunar infarcts. For this reason, lacunar infarction should be regarded as a potentially severe condition rather than a relatively benign disorder and, therefore, lacunar stroke patients require adequate and rigorous management and follow-up. Antiplatelet drugs, careful blood pressure control, the use of statins and modification of lifestyle risk factors are key elements in secondary prevention after lacunar stroke.

Classification of white matter lesions on magnetic resonance imaging in elderly persons

White matter lesions, commonly seen on MRIs of elderly people, are related to various geriatric disorders, including cerebrovascular diseases, cardiovascular diseases, dementia, and psychiatric disorders. Currently, white matter lesions are divided into periventricular white matter lesions and deep white matter lesions. Although the meaning of these terms varies by study and this dichotomization itself is still in debate, a possible dissimilarity in pathogenic mechanisms between periventricular white matter lesions and deep white matter lesions are providing some clues for understanding pathophysiology of many geriatric syndromes associated with white matter lesions. We have reviewed the distinctions between periventricular white matter lesions and deep white matter lesions in terms of etiology, histopathology, functional correlates, and imaging methodologies. We suggest a new subclassification of white matter lesions that might have better etiological and functional relevance than the current simple dichotomization. The new categories are juxtaventricular, periventricular, deep white, and juxtacortical. This new classification scheme might contribute to reducing the heterogeneity of white matter lesion findings in future research.

Lacunes and other holes: diagnosis, pathogenesis, therapy

Lacunar ischemic lesions are related to a pathology involving perforators, due to direct changes in the arteries or to an indirect mechanism, such as cardiac or artery to artery embolism, or to hypoperfusion in cases of cardiac failure, or proximal occlusion of large arteries. Changes involving the large intracranial arteries have progressively been taken into consideration as a cause of the disease. This latter aspect is interesting since possible endovascular treatment can be proposed in selected cases. In patients with lacunar syndrome an extended clinical and neuroradiological approach is indicated to choose the most appropriate therapy. Not all lesions recognizable on CT/MR are the expressions of ischemic lesions, this is another important aspect that should be considered in the differential diagnosis.

Spectrum of single and multiple corona radiata infarcts: clinical/MRI correlations

We sought to determine the clinical pictures, topography and pathogenesis of patients with unilateral single or multiple corona radiata infarcts. We defined corona radiata ischemic stroke if the patient had a focal neurological deficit and a relevant non-hemorrhagic infarction confined to the vascular territory of a long medullary artery proved by CT and MRI with contrast. We compared risk factors and clinical feature between subtypes of corona radiata infarcts. The study sample represents 1.2% of the patients (68/5500) with first-ever stroke in our Registry, including ischemic and hemorrhagic strokes. There were 37 patients (54%) with single infarct presenting 17 different complete or partial sensory-motor symptoms with dysarthria; 14 patients (21%) with unilateral multiple infarcts in one hemisphere had often complete sensorimotor deficits with some neuropsychological impairment; among 17 patients (25%) with multiple infarcts in both hemisphere, one half had bilateral motor and sensory symptoms, and neuropsychological deficits, visual field defects were uncommon. Seventeen patients (25%) had dysarthria, which was no localizing value. Hypertension was the most frequent vascular risk factor in 62% of patients, smoking in 28%, diabetes mellitus in 26%, hypercholesterolemia in 9%, and atrial fibrillation in 7%. The main cause of corona radiata infarcts was small-artery disease with long-standing hypertension in 40 patients (59%), large-artery disease in 19%, cardioembolism in 12%. Most of the patients (88%) had leukoaraiosis, and patients with bilateral multiple infarcts, leukoaraiosis was more frequent than in those with unilateral single infarct (P = .016; < .05). Despite clinical similarity to that found in superficial and deep infarcts, incomplete motor and sensory symptoms and MRI allows to delineate simultaneous uni- or multiple infarcts in the corona radiata. After an acute and immediate onset, outcome at 6 months of stroke onset is in general benign except those with bilateral infarcts. The coexistence of small-artery disease with leukoaraiosis suggest similar vascular risk factors and physiopathological mechanism.

A prospective community-based study of stroke in Kolkata, India

BACKGROUND AND PURPOSE

Information on essential stroke parameters are lacking in India. This population-based study on stroke disorder was undertaken in the city of Kolkata, India, to determine the subtypes, prevalence, incidence, and case fatality rates of stroke.

METHODS

This was a longitudinal descriptive study comprising 2-stage door-to-door survey of a stratified randomly selected sample of the city population, conducted twice per year for 2 successive years from March 2003 to February 2005.

RESULTS

Out of the screened population of 52,377 (27 626 men, 24 751 women), the age standardized prevalence rate of stroke to world standard population is 545.10 (95% CI, 479.86 to 617.05) per 100,000 persons. The age standardized average annual incidence rate to world standard population of first-ever-in-a-lifetime stroke is 145.30 (95% CI, 120.39 to 174.74) per 100,000 persons per year. Thirty-day case fatality rate is 41.08% (95% CI, 30.66 to 53.80). Women have higher incidence and case fatality rates. Despite divergence on socioeconomic status between the slum and nonslum dwellers, stroke parameters were not significantly different.

CONCLUSIONS

The age standardized prevalence and incidence rates of stroke in this study are similar to or higher than many Western nations. The overall case fatality rate is among the highest category of stroke fatality in the world. The women have higher incidence and case fatality rates compared with men.

Pathogenesis of deep white matter medullary infarcts: a diffusion weighted magnetic resonance imaging study

BACKGROUND AND PURPOSE

The pathogenesis of deep white matter medullary (WMM) artery infarcts remains controversial. To address this question, we analysed the stroke patterns of WMM infarcts using diffusion weighted magnetic resonance imaging (DWI) to detect embolic signals and investigate stroke subtypes according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classifications.

METHODS

We identified WMM infarcts on DWI using templates to determine the subcortical vascular territories. We classified WMM infarcts into those with small artery disease (SAD), large artery disease (LAD), cardioembolism (CE), two or more aetiologies, or undetermined aetiology. Clinical course, risk factors, and cortical spotty lesions were compared.

RESULTS

Of the 1420 consecutive patients, 103 (7.3%) met the criteria for WMM infarcts. The stroke subtypes were as follows: 65 (63.1%) patients with LAD, 18 (17.5%) with SAD, 12 (11.7%) with CE, four (3.9%) with two or more aetiologies, three (2.1%) with undetermined aetiology, and one (1.0%) with other determined aetiology. LAD (87.7%) or CE (83.3%) was significantly accompanied by cortical embolic signals as compared to SAD (0%, p<0.001). The LAD infarcts were larger and tended to be chain-like in shape. Ischaemic stroke recurrence was more common in strokes with cortical embolic signals than in those without embolic signals (18.9% v 0%, p = 0.009).

CONCLUSIONS

In present study, the most common pathogenesis of WMM infarcts was LAD. Our study indicates that WMM infarcts accompanying cortical embolic signals warrant evaluation of the underlying embolic sources in the large artery or the heart.

White matter lesions in watershed territories studied with MRI and parenchymography: a comparative study

Brain aging affects an increasing segment of the population and the role of chronic cerebrovascular disease is considered to be one of the main parameters involved. For this purpose we compared retrospectively MRI data with digitized subtraction angiography (DSA) data in a group of 50 patients focusing onto the watershed area of the carotid artery vascular territories. In order to evaluate the presence of white matter lesions (WML) in the hemispheric watershed areas, coronal fluid-attenuated inversion-recovery or axial T2 weighted MRI images of patients with symptomatic cerebrovascular insufficiency areas were compared with the capillary phase of DSA studies in anterior-posterior projection. Presence of cerebrovascular occlusive disease was evaluated on DSA using North American symptomatic carotid endarterectomy trial criteria and including evaluation of collateral vascular supply. Pathological MRI findings in the region of the watershed territories correlated overall in 66% of cases with a defect or delayed filling on DSA. In the case of asymmetrical MRI findings, there was a pathological finding of the capillary phase in the watershed area in 92% of DSA studies. Hypoperfusion in the capillary phase of the watershed area as seen on DSA correlated with the stenosis degree of the concerned carotid artery. Our findings suggest that asymmetrical findings of WML in the watershed areas as seen on MRI are caused by hemodynamic effect and a differentiation between small vessel disease and a consequence of distant stenosis may be possible under such conditions.

The pathophysiology of watershed infarction in internal carotid artery disease: review of cerebral perfusion studies

BACKGROUND AND PURPOSE

In carotid disease, infarcts can occur in the cortical as well as internal watershed (WS), or both. Better understanding the pathophysiology of WS infarcts would guide treatment. Two distinct hypotheses, namely low-flow and micro-embolism, are equally supported by neuropathological and physiological studies. Here we review the evidence regarding the mechanisms for WS stroke in carotid disease and whether they differ between cortical and internal WS infarcts.

SUMMARY OF REVIEW

After a brief account of the anatomy of the WS and the cerebrovascular physiology in circumstances of low perfusion pressure, the literature concerning the mechanisms of WS infarction in carotid disease is reviewed and discussed with emphasis on imaging and ultrasound studies of the cerebral hemodynamics.

CONCLUSIONS

The evidence strongly favors a hemodynamic mechanism for internal WS infarction, especially regarding the so-called rosary-like pattern in the centrum semiovale. However, the relationships between cortical WS infarction and hemodynamic compromise appear more complicated. Thus, although severe hemodynamic compromise appears to underlie combined cortical and internal WS infarction, artery-to-artery embolism may play an important role in isolated cortical WS infarcts. Based on the high prevalence of microembolic signals documented by ultrasound in symptomatic carotid disease, a recent hypothesis postulates that embolism and hypoperfusion play a synergetic role, according to which small embolic material prone to lodge in distal field arterioles would be more likely to result in cortical micro-infarcts when chronic hypoperfusion prevails. Future studies combining imaging of brain perfusion, diffusion-weighted imaging, and ultrasound detection of microembolic signals should help resolve these issues.

Isolated middle cerebral artery disease: clinical and neuroradiological features depending on the pathogenesis

BACKGROUND

Isolated atherosclerotic middle cerebral artery (MCA) disease is often difficult to differentiate from cardioembolic disease if intracranial atherosclerosis coexists with cardiac disease.

OBJECTIVES

To evaluate whether clinical and neuroradiological features of isolated MCA disease differ according to the underlying aetiology.

METHODS

Isolated MCA disease was defined as a unilateral angiographically occlusive lesion of the MCA on the symptomatic side without lesions of other intracranial or extracranial vessels. Patients with isolated MCA disease were divided into atherosclerotic and potentially cardioembolic, and the clinical, laboratory, and neuroradiological data analysed.

RESULTS

Among the 850 consecutive patients with acute ischaemic stroke or transient ischaemic attack, 107 (12.6%) met the criteria for isolated MCA disease (76 with atherosclerotic disease and 31 with a potential source of cardiac embolism). Total anterior circulation infarcts were more common and baseline NIHSS score was higher in potentially embolic occlusions than in atherosclerotic disease (each p<0.001). While cortical infarcts and territorial infarcts were more common in the potential embolism group (p = 0.028 and p<0.001, respectively), subcortical border zone infarcts were more common in the atherosclerotic group (p<0.001). Multiple regression analysis showed that border zone infarcts and mild stroke were independently associated with atherosclerotic MCA disease, while territorial and cortical infarcts were associated with potential cardiac embolic disease.

CONCLUSIONS

Clinical and neuroradiological characteristics can differentiate isolated atherosclerotic MCA disease from MCA disease associated with potential sources of cardiac embolism, and may reflect the differences in underlying pathogenesis.

Subcortical white matter infarcts: comparison of superficial perforating artery and internal border-zone infarcts using diffusion-weighted magnetic resonance imaging

BACKGROUND AND PURPOSE

Because of difficulty in distinguishing between superficial perforator (SP) and internal border-zone (IB) infarcts, some studies lumped SP and IB infarcts together as so-called subcortical white matter infarcts, which might complicate the classification of infarct type and its pathogenesis. Using diffusion-weighted MRI (DWI), we made comparative analyses of clinical and neuroradiological characteristics between IB and SP infarcts to clarify the difference in underlying pathogenesis.

METHODS

We selected SP and IB infarcts on DWI using templates for the identification of subcortical vascular territories. Sex, age, neurological symptoms, clinical course, risk factors, concomitant cortical spotty lesions, and degree and location of arterial occlusive disease were compared between the 2 groups.

RESULTS

Among the 720 consecutive patients, 54 and 29 patients met the criteria for SP and IB infarcts, respectively. The SP group had lower initial National Institutes of Health Stroke Scale scores (2.4+/-2.1 versus 4.4+/-3.1; P=0.001), favorable clinical outcomes (P=0.001), and more frequent potential cardioembolic sources (14.8% versus 0%; P=0.046) than the IB group. Cortical spotty lesions were more frequently accompanied by SP than IB infarcts (72.2% versus 24.1%; P<0.001). IB infarcts were larger (24.2+/-10.2 versus 11.4+/-8.5 mm; P<0.001), appeared in a chainlike fashion (72.4% versus 33.3%; P=0.001), and had a higher degree of stenosis or occlusion (86.2% versus 46.3%; P=0.001) compared with SP infarcts.

CONCLUSIONS

Our present study suggests that embolic pathogenesis makes a greater contribution to SP infarcts than IB infarcts. This finding may explain the difference in clinical and neuroradiological characteristics between the 2 groups.

DWI findings of periventricular ischemic changes in patients with leukoaraiosis

In this report the diffusion-weighted imaging (DWI) findings and ADC values of leukoaraiosis (LA) and associated periventricular ischemic lesions were assessed. Seventy-eight patients with LA were examined with magnetic resonance imaging (MRI) and DWI. Twenty one patients (28%) were found to have focal acute white matter infarction on DWI which could not be detected and discriminated on the basis of MRI findings alone. LA and acute white matter infarction both showed hyperintensity on standard T2W MRI, whereas acute infarction revealed focal hyperintensity on DWI. Thirteen patients (16%) had chronic lacunar infarctions in the white matter. ADC values of LA, acute and chronic white matter infarctions were calculated and found to be significantly different from each other (p<0.05). It is concluded that DWI is necessary in the detection of acute periventricular white matter infarction from LA.

Small centrum ovale infarcts on diffusion-weighted magnetic resonance imaging

BACKGROUND AND PURPOSE

A small centrum ovale infarct (SCOI), caused by occlusion of the white matter medullary arteries, is often equated with a lacunar infarct. We sought to clarify the clinical characteristics of a SCOI visualized by diffusion-weighted MRI (DWI) compared with those of a small basal ganglia infarct (SBGI).

METHODS

Patients with a SCOI (SCOI group; n=38) or SBGI (SBGI group; n=68) < or =15 mm in diameter on conventional MRI and DWI were selected from 582 consecutive patients with acute ischemic stroke. Sex, age, neurological symptoms, vascular risk factors, emboligenic heart disease, arterial occlusive disease in the ipsilateral carotid system, and recurrent stroke within the initial 30 days were compared between the 2 groups.

RESULTS

Only 47% of SCOIs but 87% of SBGIs could be identified with the use of conventional MRI, whereas DWI could detect them all. Age, sex, and vascular risk factors were not significantly different between the 2 groups. The SCOI group had more frequently an abrupt onset of symptoms (63% versus 26%; P=0.0002), emboligenic heart diseases (34% versus 12%; P=0.0054), occlusive carotid and/or middle cerebral artery diseases (53% versus 19%; P=0.0004), and recurrent stroke (13% versus 1%; P=0.0216) but less frequently a classic lacunar syndrome (50% versus 81%; P=0.0009) than the SBGI group. On a multivariate analysis, both arterial and heart diseases were independently associated with the SCOI group.

CONCLUSIONS

Symptomatic SCOIs detected by DWI may be associated with large-vessel and heart diseases and should be distinguished from lacunar infarcts.

Linear hyperintensity objects on magnetic resonance imaging related to hypertension

Linear hyperintensity lesions, which are sometimes recognized in the cerebral white matter on T(2)-weighted magnetic resonance (MR) images, have never been studied from the clinical viewpoint. We refer to these lesions as linear hyperintensity objects (LHOs) and have investigated them quantitatively. Twenty-six consecutive patients underwent routine 1.5-Tesla MR imaging. LHOs were found in 24 patients. We measured the width and number of LHOs at the upper corona radiata level on T(2)-weighted images (repetition time: 4,500.0 ms, echo time: 96.0 ms) using a scale loupe. The diameters were significantly correlated with the stages of hypertension (WHO classification). The LHOs may associated with the dilated perivascular spaces of cortical medullary arteries and may become an indicator for hypertensive small vessel disease.

Internal borderzone infarction: a marker for severe stenosis in patients with symptomatic internal carotid artery disease. For the North American Symptomatic Carotid Endarterectomy (NASCET) Group

BACKGROUND AND PURPOSE

Among subcortical infarctions, internal borderzone infarcts (IBI) are considered to be separate entities from perforating artery infarcts (PAI). The purpose of the present study is to examine the relationship between the presence of IBI and the degree of angiographically defined internal carotid artery (ICA) stenosis in symptomatic patients.

METHODS

A review of 1253 brain CTs from patients recruited by the North American Symptomatic Carotid Endarterectomy Trial was performed, using templates for the identification of subcortical and cortical vascular territories.

RESULTS

A total of 413 patients had visible ischemic lesions on the side ipsilateral to their symptomatic ICA. Of these, 138 had PAI, 108 had IBI, 122 had cortical infarcts, and 45 had a combination of different lesions. Mean (+/-SD) lesion diameter was larger for IBI (11.0+/-5.9 mm) than for PAI (7.1+/-4.7 mm) (P<0.001 for comparing 2 means). IBI was associated with higher degrees of ICA stenosis (P<0. 001). Sixty-three percent of the patients with IBI had severe (70% to 99%) ICA stenosis compared with 42% of patients with PAI; 18% of the IBI patients had stenosis of 90% or more compared with 8% of the patients with PAI. Multiple logistic regression did not identify any patient characteristics as confounders.

CONCLUSIONS

Among subcortical infarctions, IBI are associated with higher degrees of ICA stenosis in symptomatic patients. Differentiating between internal borderzone and perforating artery infarcts is important, because each may arise from different mechanisms, namely, carotid disease and small-vessel disease, respectively.