Internal Border Zone Infarcts Research Articles

Characteristics of Atherosclerotic Plaques and Stroke Mechanism in Patients with Border-Zone Infarcts: A High-resolution Magnetic Resonance Imaging Study

BackgroundRelatively little is known about the plaque characteristics of border-zone infarcts and how they differ between cortical border-zone (CBZ) and internal border-zone (IBZ) infarcts. MethodsWe conducted a prospective observational cohort study of patients of intracranial atherosclerotic disease who underwent high-resolution magnetic resonance imaging (HR-MRI) examination. Individuals with border-zone infarcts in the middle cerebral artery (MCA) territory, detected by diffusion-weighted imaging, were enrolled. Plaque morphological and compositional parameters of both IBZ and CBZ groups were compared. Independent predictors were identified using a binary logistic regression model, and the sensitivity and specificity of the model were assessed using a receiver operating characteristic curve. Kaplan-Meier survival analysis further explored differences in stroke recurrence between BZ patients with mono or dual antiplatelet therapy. ResultsWe reviewed 101 symptomatic patients with border-zone infarcts (BZ) within the MCA territory in the study. Out of the patients meeting the imaging eligibility criteria, we detected 34 cases with isolated IBZ, 23 cases with isolated CBZ, and 6 cases with both IBZ and CBZ infarcts. Those with IBZ infarcts had a higher plaque burden than those without (p<0.001), and those with CBZ infarcts exhibited a complicated plaque less frequently than those without (37.9% vs 67.6%, p=0.018). In those with isolated IBZ or CBZ infarcts, plaque burden was independently associated with isolated IBZ infarcts (odd ratio=1.08; 95% CI, 1.02-1.15; p=0.023). During the median follow-up period of 37 (27, 50) months, 13.8% of patients receiving early dual antiplatelet treatment and 30.4% of those on single antiplatelet therapy experienced stroke recurrence (p=0.182). ConclusionsIntracranial atherosclerotic plaque morphology and composition differ between patients with IBZ and those with CBZ infarcts. Higher plaque burden is more associated with IBZ infarcts.

Cerebral hemodynamics and stroke risks in symptomatic intracranial atherosclerotic stenosis with internal versus cortical borderzone infarcts: A computational fluid dynamics study

There may be different mechanisms underlying internal (IBZ) and cortical (CBZ) borderzone infarcts in intracranial atherosclerotic stenosis. In 84 patients with symptomatic, 50-99% atherosclerotic stenosis of M1 middle cerebral artery (MCA-M1) with acute borderzone infarcts in diffusion-weighted imaging, we classified the infarct patterns as isolated IBZ (n = 37), isolated CBZ (n = 31), and IBZ+CBZ (n = 16) infarcts. CT angiography-based computational fluid dynamics models were constructed to quantify translesional, post-stenotic to pre-stenotic pressure ratio (PR) in the MCA-M1 lesion. Those with IBZ infarcts were more likely to have a low PR (indicating impaired antegrade flow across the lesion) than those without (p = 0.012), and those with CBZ infarcts were more likely to have coexisting small cortical infarcts (indicating possible embolism) than those without (p = 0.004). In those with isolated IBZ or CBZ infarcts, low PR was independently associated with isolated IBZ infarcts (adjusted odds ratio = 4.223; p = 0.026). These two groups may also have different trajectories in the stroke risks under current medical treatment regimen, with a higher risk of same-territory ischemic stroke recurrence within 3 months in patients with isolated IBZ infarcts than isolated CBZ infarcts (17.9% versus 0.0%; log-rank p = 0.023), but similar risks later in 1 year.

[Related factors of internal border-zone infarcts in patients with symptomatic chronic internal carotid artery occlusion].

Objective: To explore the related factors of internal border-zone (IBZ) infarcts in patients with symptomatic chronic internal carotid artery occlusion (CICAO). Methods: From January 2011 to May 2019, the symptomatic CICAO patients in the Second Affiliated Hospital of Soochow University and the Ninth People's Hospital of Suzhou were retrospectively analyzed. The patients were divided into IBZ group and non-IBZ group. The demographic data, laboratory examination and imaging data of the two groups were collected. Binary logistic regression analysis was used to identify the related factors of IBZ infarcts in patients with symptomatic CICAO. Results: A total of 185 patients (147 males and 38 females) were finally enrolled, with a mean age of (65±11) years old. There were 64 and 121 cases in IBZ group and non-IBZ group, respectively. The ratio of patients with ophthalmic artery (OA) reflux in IBZ group was 64.1% (41/64), which was significantly higher than that in non IBZ group [47.8% (55/121), P=0.037], while the ratio of patients with collateral compensation (ASTIN/SIR 3-4) in non-IBZ group was 66.1% (80/121), which was significantly higher than that in IBZ group [29.7% (19/64), P<0.001]. Multivariate logistic regression analysis showed that history of cerebral infarction (OR=2.233, 95%CI: 1.023-4.874), low density lipoprotein (LDL) (OR=1.516, 95%CI: 1.006-2.285) and OA reflux (OR=5.060, 95%CI: 1.160-22.081) were independent risk factors for IBZ infarcts in patients with symptomatic CICAO (all P<0.05); while prothrombin international normalized ratio (INR) (OR=0.010, 95%CI: 0.000-0.970) and collateral compensation (ASTIN/SIR 3-4) (OR=0.172, 95%CI: 0.079-0.373) were protective factors (all P<0.05). Conclusion: OA reflux, LDL, and history of cerebral infarction are independent risk factors for IBZ infarcts in patients with symptomatic CICAO, while INR and collateral compensation scores (ASTIN/SIR 3-4) are the protective factors.

Vasomotor reactivity in patients with cerebral small vessel disease vs. internal border zone infarction and its correlation with disease outcome

BackgroundAvailable data collected from patients of different types of cerebrovascular strokes can detect risk factors, severity and clinical outcome of these patients. Differentiating between different types of strokes is mandatory for early diagnosis and proper management. The aim of this study is to compare between cerebral small vessel disease with lacunar infarctions and internal border zone infarctions regarding vasomotor reactivity by using transcranial color-coded duplex and its correlation with their MRI perfusion, disease severity and outcome.ResultsOn admission, 56.7% of patients in lacunar stroke had impaired reactivity vs. 100% of patients in internal border zone group. At 3 months follow-up, this number dropped to 23.3% in lacunar group, but persisted as 100% in internal border zone group. On comparing the 3 perfusion parameters between the 2 groups, there was statistically significant impairment in all parameters in patients with internal border zone infarction than patients with lacunar infarction (longer time to peak, decreased cerebral blood flow and cerebral blood volume). By comparing the severity of the stroke by using National Institute of Health and Stroke Scale, it was found that patients with internal border zone infarction had higher disability than patients with lacunar infarction on admission and on discharge. At 3 months follow-up, the lacunar group had a better outcome than of the border zone group.ConclusionPatients having internal border zone infarction had higher clinical disability and worse prognosis, together with more impairment in vasomotor reactivity and MRI perfusion parameters than patients having lacunar infarction.

Hemophilia A developing cerebral infarction after surgical treatment of giant hemophilic pseudotumor: a case report

BackgroundCerebral infarction (CI) is an unusual complication in patients with bleeding disorders. To our knowledge, this is the first case of postoperative internal border-zone infarction (I-BZI) from Hemophilia A.Case presentationWe present a case of Hemophilia A developing I-BZI, after surgical treatment of giant hemophilic pseudotumor. A 36-year-old man was introduced from other hospital by Hemophilia with giant hemophilic pseudotumor in his left thigh. Patient and his relatives did not have a history of thrombophilia. After excluding the relevant surgical contraindications, we performed the operation of pseudotumor resection. Prior to surgery, blood tests revealed hemoglobin of 137 g/L. FVIII activity was 1.5%. Activated partial thromboplastin time (APTT) was 71.50 s and D-dimer was 3.33 mg/L FEU. Immediately before surgery, the patient received an intravenous infusion of FVIII products (Xyntha®) at a dose of 3500 IU for his body weight of 80 kg. Post-operative day two (POD2), patient developed vomiting, decreased response, and dysarthria. Hemoglobin was 54 g/L with blood pressure of 110/70 mmHg. Magnetic resonance imaging of the brain showed there were multiple acute cerebral infarctions in bilateral lateral ventricles (internal border zone) and multiple ischemic foci in the white matter areas and basal ganglia of the bilateral cerebral hemispheres. This case suggested that acute severe anemia can be one of the causes of I-BZI.ConclusionsFor the treatment of I-BZI caused by acute anemia from Hemophilia A, volume expansion, red blood cell supplement and continuous improvement of coagulation with suitable dose of factor VIII (FVIII) should be considered to improve prognosis.

Border-Zone Infarction Due to Cerebrovascular Fibromuscular Dysplasia.

A 45-year-old male presented with acute-onset left-sided weakness and slurred speech. Non-contrast-enhanced brain magnetic resonance imaging revealed cortical and internal border-zone infarcts compatible with stroke. A survey of ischemic stroke risk factors in young adults excluded coagulopathy, vasculitis, and cardiac disease. Nevertheless, neck-computed tomography angiography revealed a long-segmental narrowing of the right internal carotid artery with wall thickening and a “string-of-beads” appearance suspicious for fibromuscular dysplasia, which was confirmed on further angiography. His clinical condition stabilized after intensive medical therapy. This case demonstrates cerebrovascular fibromuscular dysplasia as a possible cause of ischemic stroke in young adults.

The clinical and neuroradiological features of patients of coexisting atraumatic convexity subarachnoid hemorrhage and large artery atherosclerosis stroke: A retrospective observational study.

Atraumatic convexity subarachnoid hemorrhage (c-SAH) concomitant with large artery atherosclerosis (LAA) stroke has been rarely discussed in the literature. Our aim in this study is to characterize the clinical and neuroradiological features of patients with LAA stroke and c-SAH.A retrospective study from a single institution was performed between January 2016 and June 2020. Only patients diagnosed with c-SAH and LAA stoke were included in this study. The clinical presentation and neuroimaging finding were summarized by our experienced neurologists.In total, 12 patients (8 men, 4 women), ranging in age from 45 to 75 years, were identified. All of them had cardiovascular risk factors and hypertension was the commonest (50%). Almost all patients presented hemiparesis (91.7%). Other clinical presentations included, dysarthria (41.7%), hemianesthesia (33.3%), facial palsy (33.3%), aphasia (16.7%), and cognitive impairment (8.3%). Internal border-zone (IBZ) infarction and cortical border-zone (CBZ) infarction occurred in 12 and 3 patients, respectively. c-SAH might occurred in different cortical sulcis. Percentages of frontal lobe, parietal lobe and fronto-parietal lobe were 41.7% (n = 5), 25% (n = 3) and 25% (n = 3), respectively. All ischemic lesions were ipsilateral to the sites of c-SAH. High-grade atherosclerotic stenosis of large artery was detected in all patients. The M1 segment of middle cerebral artery (MCA) is the second most common atherosclerotic artery after internal carotid artery (ICA).Our data suggest that LAA stroke is always ipsilateral to the site of c-SAH. Severe atherosclerotic changes can also been seen in the M1 segment of MCA apart from extracranial ICA. Moreover, border zone infarction may be a specific form of infarct when c-SAH is confronted with LAA stroke.

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

ObjectivesTo examine the existence and significance of internal border zone (IBZ) infarcts with accessory lesions in the anteromedial temporal lobe (ATL). Materials and methodsIBZ 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. ResultsThirty-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. ConclusionsOur 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.

Intravascular Lymphoma Presenting as Internal Border-zone Infarcts (2329)

Intravascular Lymphoma Presenting as Internal Border-zone Infarcts (2329)

Abstract WP183: Borderzone Infarcts Predict Early Recurrence in Patients With Large Artery Atherosclerotic Subtype Despite Medical Treatment

Introduction: Large artery atherosclerosis subtype carries a high risk of early recurrent stroke despite medical management. Predictors of recurrence remain poorly understood. We hypothesized that borderzone infarcts are associated with a higher risk of recurrence. Objectives: We aim to investigate infarct patterns and 90-day recurrence in patients with symptomatic intracranial and/or extracranial atherosclerotic disease. Methods: We included consecutive patients admitted to NYU Langone Health (Manhattan and Brooklyn campuses) over 32-months with a diagnosis of acute ischemic stroke secondary to symptomatic intracranial or extracranial atherosclerosis. The primary predictor was infarct pattern (borderzone vs. non-borderzone infarction), defined in accordance to previous studies. Borderzone infarcts were divided into internal borderzone and cortical borderzone. We used univariate and multivariable cox-regression models to determine associations between infarct pattern and recurrent cerebrovascular events (RCVE) at 90-days. Results: Fifty-five patients met the inclusion criteria; 38 were intracranial, 3 tandem, 14 extracranial. Nearly 71% of patients were treated with dual antiplatelet therapy and 96% were treated with high intensity statin. The RCVE rate was 23.6%. In multivariable models, borderzone infarcts were associated with increased risk of RCVE (adjusted HR 9.8 95% CI 2.1-44.8, p=0.003). The risk of RCVE was highest among internal borderzone infarcts (47.3%) as opposed to cortical borderzone infarcts (33.3%) or non borderzone infarcts (18.8%). Conclusions: Borderzone (and particularly internal borderzone) infarcts are a surrogate marker of impaired distal blood flow and are associated with RCVE despite medical treatment. This highlights the need to develop alternate treatment strategies for this high-risk cohort.

Increased Volume and Distinct Pattern of Silent Cerebral Infarcts in Healthy, Young Adults with Sickle Cell Trait

▪Background: Sickle cell trait (SCT) is common, affecting 7-8% of African Americans. Previously thought to be of little clinical consequence except under conditions of severe hypoxic/metabolic stress, recent studies have shown that SCT is independently associated with chronic vascular diseases including kidney disease, coronary artery disease, overt stroke, and pulmonary embolism. It has been postulated that SCT underlies the increased prevalence of cerebrovascular disease in African-Americans after adjusting for excess risk factors. Prospective imaging studies evaluating the natural history of cerebral ischemia in SCT are lacking; thus, the true disease burden is unknown. In this study, we hypothesized that individuals with SCT are at increased risk of silent cerebral infarctions (SCI) compared to healthy young adults, but with a lower risk of SCIs compared to young adults with sickle cell anemia (SCA). We further evaluated and compared the patterns of SCIs within SCT and SCA.Methods: Three cohorts were prospectively recruited from a tertiary care referral center for pediatric and adult SCA: (1) young adults with SCA, (2) healthy, young adults with SCT, and (3) healthy, age- and race-matched, controls. Control and SCT subjects were excluded for history of hypertension, diabetes, anemia, dyslipidemia, chronic medical or neurological illness, or severe trauma; individuals with SCA were excluded if on chronic transfusion therapy or history of overt stroke, vasculopathy, or chronic neurological illness. Brain MRI T1 and FLAIR maps were evaluated for the presence of two lesion types (defined in Wardlaw et al, Lancet Neurol, 2013): (a) FLAIR lesions were defined as FLAIR hyperintensity > 3mm in diameter; (b) SCIs were defined as FLAIR lesions with the additional requirement of CSF-like hypointensity on T1. Thus, SCIs represented a subset of all FLAIR lesions. FLAIR lesions were outlined by a vascular neurologist using MIPAV (Medical Image Processing, Analysis and Visualization, https://mipav.cit.nih.gov/) from which individual lesion volumes were calculated. Baseline characteristics, prevalence of SCIs, and volume of FLAIR lesions in SCT were compared to controls and SCA (Fishers Exact for categorical variables; Mann-Whitney U for continuous variables). To evaluate the distribution of SCIs in SCT relative to healthy controls and SCA, three lesion density maps were created. Lesions drawn on FLAIR 5mm slice thickness were stretched in the z-direction to 10mm for display of SCI pattern on few slices.Results: Control, SCT, and SCA adults were similar with respect to baseline characteristics, except SCA subjects were younger and fewer female than SCT (Table). Ten (45%) of the SCA subjects were on hydroxyurea. We acquired LDL, glucose, and blood pressure to ensure that SCT participants did not have higher risk of SCIs compared to controls due to ongoing comorbidities (Table). Imaging Outcomes: We found greater FLAIR lesion volumes in SCT than controls (292 vs. 90 mm3, p=0.02) and a trend towards greater prevalence of SCIs – 5 of 11 (45%) in SCT compared to 1 of 11 (9%) in controls (p=0.15). FLAIR lesion volumes and SCI prevalence were higher in SCA compared to SCT (p=0.01 and p=0.02, respectively). Lesion density maps (Figure) were created to evaluate SCI patterns in SCT and SCA. In the SCA cohort, lesion density was highest within the internal borderzone (where cerebral blood flow is at a nadir), while this region was relatively unaffected in SCT. In contrast, a distinct pattern of small cortical/subcortical strokes distributed in a stochastic pattern (not following any particular vascular territory) were found in both SCT and SCA.Conclusions: We found greater FLAIR lesion volumes and a trend towards a greater prevalence of SCIs in healthy individuals with SCT. We postulate that SCIs found in SCT may represent an etiologic subtype of SCIs found in SCA, representing microembolic events or a microvasculopathy, in contrast to the etiology of internal borderzone infarction which likely represents a heightened ischemic vulnerability within low CBF regions in the setting of chronic, severe anemia. Larger studies are necessary to determine if SCT carries a heightened risk of silent cerebral ischemia, which would impact society at large given the high prevalence of SCT and the known effects of SCIs on cognitive disability. [Display omitted] DisclosuresFields:Proclara Biosciences: Equity Ownership. Hulbert:Pfizer: Other: Spouse employment at Pfizer.

Subacute Percutaneous Cerebral Balloon Angioplasty for Middle Cerebral Artery Occlusion in Patients with Internal Border Zone Infarcts.

Background We report our initial experiences of subacute percutaneous cerebral balloon angioplasty (PTCBA) for atherothrombotic middle cerebral artery (MCA) occlusion in patients with internal border zone (IBZ) infarcts more than 1 week after stroke onset. Methods Included in the retrospective analysis were patients (1) who were admitted to our institution between 3 and 72 hours after an atherothrombotic stroke onset, (2) whose diffusion-weighted image at admission showed small high-intensity lesions in the IBZ area, (3) whose magnetic resonance angiography at admission displayed the MCA occlusion, (4) whose computed tomography scans on day 7 showed the IBZ infarcts, (5) whose National Institutes of Health Stroke Scale (NIHSS) score was ≥ 10 on day 7, and (6) whose neurologic symptoms deteriorated day by day within 7 days of onset (a > 4-point increase on the NIHSS) despite medical therapy. Results Ten patients met our criteria and were informed of their treatment options including angioplasty and/or stenting for atherothrombotic MCA occlusion in a subacute stroke stage. Four patients gave written informed consent and underwent subacute PTCBA; six did not. Although there were no significant differences in the prestroke modified Rankin Scale (mRS), NIHSS on admission and NIHSS on day 7 after onset between the two groups, 3-month mRS score (median) was 3 in the PTCBA group and 5 in the medical treatment group (p < 0.05). Conclusion Subacute PTCBA for atherothrombotic MCA occlusion may be effective in improving long-term clinical outcome in patients with IBZ infarcts.

Clinical Significance of Fluid-Attenuated Inversion Recovery Vascular Hyperintensities in Borderzone Infarcts.

Fluid-attenuated inversion recovery vascular hyperintensities (FVHs) are seen in some cases with cerebral hemodynamic impairment and collateral flow. Because the worst outcomes of patients with borderzone infarcts were mainly correlated with impaired hemodynamics, the presence of FVH might provide another clue for predicting the prognosis of patients with borderzone infarcts. We reviewed 1377 consecutive patients with ischemic stroke. Cortical borderzone (CBZ) and internal borderzone infarcts were selected based on diffusion-weighted imaging. FVHs were defined as tubular- or serpentine-shaped hyperintensities in the subarachnoid space. We investigated the clinical significance of FVHs in borderzone-infarcted patients. Among 87 patients with borderzone infarcts, the presence of FVH was observed in 30 (34.5%). We identified 62 patients with CBZ infarcts and 25 patients with internal borderzone infarcts. In the cases with CBZ infarcts, the initial National Institutes of Health Stroke Scale scores and the portions of nonfavorable outcome at 3 months in the FVH(+) group were significantly higher than in the FVH(-) group (P<0.05 and P<0.001, respectively). Unlike the cases with CBZ infarcts, there were no significant differences of these clinical features between the FVH(+) group and the FVH(-) group in the patients with internal borderzone infarcts. The findings of FVH are associated with relatively severe clinical presentation and nonfavorable prognosis in patients with CBZ infarcts, but not in patients with internal borderzone infarcts. The presence of FVH may help to identify CBZ-infarcted patients who require close observation and hemodynamic control.

Early Magnetic Resonance Imaging Predicts Early Neurological Deterioration in Acute Middle Cerebral Artery Minor Stroke

Early neurological deterioration (END) is an important factor associated with worse clinical outcome in minor strokes. Early magnetic resonance imaging (MRI) findings can provide better sensitivity to delineate stroke pathophysiology and have diagnostic value associated with causative mechanisms. The aim of this study was to investigate the relationship between early MRI finding and the presence of END in minor stroke patients with lesions in the middle cerebral artery (MCA) territory. Consecutive MCA minor stroke patients who were admitted to our center within 24 hours of symptom onset were included in this study. All patients underwent MRI within 24 hours of admission. We analyzed baseline characteristics, infarction patterns, and treatment algorithms. The correlation between early MRI findings and END, defined as National Institutes of Health Stroke Scale score increasing more than 2 points during 72 hours after admission, was also determined. Across 211 patients meeting entry criteria between January 2010 and December 2013, internal border-zone (IBZ) infarcts on early MRI scan were observed in 23 of 65 patients with END (35.4%) and in 18 of 146 patients without END (12.3%, P < .001). Patients with IBZ infarcts were found to have more hyperlipidemia, less perforating artery infarcts, more pial artery infarcts, more cortical border-zone infarcts and more ipsilateral large arterial stenosis. Logistic regression analysis revealed that IBZ infarct was independently associated with END after adjustment for other factors (odds ratio, 2.50; 95% confidence interval, 1.09-5.74; P = .031). Early MRI patterns of IBZ infarction are associated with END in minor stroke patients with acute infarcts of the MCA territory.

Relationship between visible branch arteries distal to the stenosis on magnetic resonance angiography and stroke recurrence in patients with severe middle cerebral artery trunk stenosis: a one-year follow up study.

BackgroundTo evaluate the relationship between the flow signal intensity of branch arteries distal to the stenosis on 3-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) and the risk of stroke recurrence in patients with severe middle cerebral artery (MCA) trunk stenosis.MethodsWe prospectively recruited 153 patients (mean age 62.9 ± 13.0 years, 106 males) with a first ischemic stroke or transient ischemic attack caused by a severe MCA trunk stenosis (70 % to 99 %) confirmed by 3D TOF MRA and followed them for one year to determine the stroke recurrence. The MCA branch signal intensity distal to the site of stenosis on 3D TOF MRA was classified as either good (grade A) or poor [mild reduction (grade B) or severe reduction (grade C)] according to the extent to which the MCA could be visualized. The patients were divided into groups A (35), B (58), or C (60) based on the MRA grading of the MCA branch signal intensity distal to the site of stenosis.ResultsPoor MCA branch signal intensity was associated with internal border-zone infarction (p < 0.05). The risk of stroke recurrence in the ipsilateral MCA in the first year was 18.3 %. The 1-year cumulative incidence of recurrence was higher in the patients in group C (30 %) than in groups B (12.1 %) or A (8.6 %) (Log rank, p = 0.007). Multivariate analyses via Cox proportional hazard regression demonstrated that only a grade C classification of the signal intensity of the MCA branches was an independent predictor of stroke recurrence in the ipsilateral MCA (hazard ratio = 3.0, 95 % confidence interval = 1.3-7.4, p = 0.014).ConclusionsThis study demonstrated that MCA branch signal intensity as assessed via 3D TOF MRA may be a useful and simple tool to stratify the risk of stroke recurrence in patients with severe MCA trunk stenosis.

Abstract T P55: Infarction Patterns Predict Differential Response to Thrombolysis in Acute Middle Cerebral Artery Stroke Patients

Introduction: Thrombolytic treatment within 4.5 hours saves ischemic tissue at risk and is associated with improved clinical outcomes in patients with acute middle cerebral artery (MCA) ischemic stroke. Lesion pattern is one of the most important predictors for acute stroke patients’ outcome. However, the efficacy of thrombolysis in acute MCA stroke patients with different lesion patterns remains unclear. In this study, we aimed to compare response to intravenous tPA in patients with different infarction patterns. Methods: We included acute MCA ischemic stroke patients treated with intravenous tPA. All patients had DWI within 24 hours of symptom onset with 6 lesion patterns categorized as territorial, other cortical, small superficial, internal border zone, small deep, and other deep infarcts. We classified territorial infarcts and internal borderzone into Group 1 and the other four lesion patterns as Group 2. We analyzed clinical outcome after tPA based on these distinct DWI lesion patterns. Results: A total of 203 patients were included in our study. Mean age was 66.2±18.1.The percent of patients with hypertension at presentation is higher in Group 1 than in Group 2(100% VS 93.8%, p=0.049). The presenting NIHSS of Group 1 is higher than Group 2 (18.0 vs 12.0, p&lt;0.001). After intravenous tPA therapy, the proportion of patients progressing to intra-arterial tPA and/or endovascular thrombectomy in Group 1 was similar to Group 2 (22.0% vs 22.2%, p=0.98). As to the clinical outcome, the percent of patients with discharge mRS≤2 in Group 1 is much higher than that Group 2 (33.9% vs 20.1% p=0.038). Logistic regression demonstrated that infarction patterns were independently associated with discharge outcome of these patients. Conclusion: Good response to intravenous tPA was more frequent in patients with territorial infarcts and internal border zone infarcts, indicating that particular DWI infarction patterns can predict good outcome of acute MCA patients after thrombolysis.

The Relationship between Neurological Worsening and Lesion Patterns in Patients with Acute Middle Cerebral Artery Stenosis

Background: Intracranial atherosclerotic disease is one of the most common causes of ischemic stroke especially in Asians, Hispanics and blacks. Although middle cerebral artery (MCA) stenosis is increasingly being recognized with the advent of magnetic resonance angiography (MRA) or transcranial Doppler ultrasonography, few studies have focused on acute neurological worsening (NW) in patients with MCA stenosis. We investigated the relationship between NW and lesion patterns detected by diffusion-weighted imaging (DWI). Methods: We studied 44 consecutive patients out of a total of 2,863 consecutive patients who had symptomatic lesions in the territory of the MCA and in whom MRA and/or conventional angiography showed isolated MCA stenosis ≥50% in the MCA trunk. Acute DWI lesion patterns were classified as follows: (1) pial artery territory infarcts (PAI); (2) small cortical and/or subcortical infarcts (SCS); (3) deep penetrating artery territory infarcts (DPI); (4) cortical border zone infarcts (CBZ), and (5) internal border zone infarcts (IBZ). NW was defined as worsening by ≥2 points on the National Institutes of Health Stroke Scale (NIHSS) during the first 7 days. Functional outcome was assessed by the modified Rankin Scale (mRS) at 3 months after stroke onset. Poor outcome was defined as ≥3 on the mRS. The severity of MCA stenosis on MRA was further categorized as 50-75% (moderate) and >75% or focal signal loss with the presence of distal MCA signal (severe). Results: There were 14 patients (31.8%) who showed NW and 16 patients (36.3%) who showed poor outcomes. Nine of the 14 patients with NW showed poor outcomes (64.2%). The most frequent lesions in the present study were SCS (n = 16, 36.3%), followed by IBZ (n = 12, 27.2%) and DPI (n = 11, 25.0%). Prevalence of IBZ was significantly higher in the group with NW compared to that without NW (p = 0.0081), while the prevalence of SCS, DPI, PAI and CBZ did not differ between the two groups. Logistic regression analysis showed significantly high age- and sex-adjusted odds ratios (ORs) for NW only for IBZ (OR 10.9, p = 0.0051). The degree of stenosis did not correlate with NW and lesion patterns. Conclusions: Only IBZ among various lesion patterns correlated strongly with NW. IBZ are considered to be more associated with hemodynamic compromise, while embolic pathogeneses contribute more to CBZ or SCS. Early interventional medical treatments such as thrombolytic or anti-platelet therapy or stenting should be considered in cases of IBZ in MCA stenosis.

Border Zone Infarcts: Pathophysiologic and Imaging Characteristics

Border zone or watershed infarcts are ischemic lesions that occur in characteristic locations at the junction between two main arterial territories. These lesions constitute approximately 10% of all brain infarcts and are well described in the literature. Their pathophysiology has not yet been fully elucidated, but a commonly accepted hypothesis holds that decreased perfusion in the distal regions of the vascular territories leaves them vulnerable to infarction. Two types of border zone infarcts are recognized: external (cortical) and internal (subcortical). To select the most appropriate methods for managing these infarcts, it is important to understand the underlying causal mechanisms. Internal border zone infarcts are caused mainly by hemodynamic compromise, whereas external border zone infarcts are believed to result from embolism but not always with associated hypoperfusion. Various imaging modalities have been used to determine the presence and extent of hemodynamic compromise or misery perfusion in association with border zone infarcts, and some findings (eg, multiple small internal infarcts) have proved to be independent predictors of subsequent ischemic stroke. A combination of several advanced techniques (eg, diffusion and perfusion magnetic resonance imaging and computed tomography, positron emission tomography, transcranial Doppler ultrasonography) can be useful for identifying the pathophysiologic process, making an early clinical diagnosis, guiding management, and predicting the outcome.

Internal Border Zone Lesions as a Predictor of Early Neurological Deterioration in Minor Stroke Patients with Severe Arterial Steno-Occlusion

Early neurological deterioration (END) of acute ischemic stroke may be important because it can predict clinical outcomes. We described several cases with similar clinical findings but different outcomes and analyzed the characteristics of their imaging studies. We retrospectively analyzed minor stroke patients with severe arterial stenosis within 6 hours of stroke onset. We defined END as 4 or more deterioration of the National Institutes of Health Stroke Scale score. Diffusion-weighted imaging (DWI) lesions were classified as lesions of the pial artery (PI), perforating artery (PAI) and border-zone (BZ). We consecutively analyzed a total of 12 subjects in this study. The patterns of initial DWI lesions were internal BZ (50%), PI (50%), PAI (25%), and cortical BZ (16.7%). Among them, the number of subjects with END was 5, and the frequency of internal BZ on initial DWI was significantly higher in patients with END than in those without. In conclusion, the results of this study suggest that when internal BZ infarcts are detected in patients with acute minor strokes accompanied by severe arterial stenosis, close observation and careful management should be performed because END can be induced at an early stage.

Association of Internal Border Zone Infarction with Middle Cerebral Artery Steno-Occlusion

Background: Demonstrating the precise anatomical area of the internal border zone (IB) by brain imaging has been unclear, and it is not well known which relevant arteries are associated with IB infarction. Methods: Patients with IB infarctions were selected from 748 consecutive patients with acute ischemic stroke. The IB infarctions were identified by coronal diffusion-weighted imaging, excluding lesions over the upper pole of the lateral ventricle. The angiographic findings of the internal carotid artery (ICA) and middle cerebral artery (MCA), on contrast-enhanced MRA, were evaluated in the patients with and without IB infarction. Results: Thirty patients met the criteria for an IB infarction: 7 had MCA steno-occlusion without ICA disease, and 23 had ICA steno-occlusion. Sixty-one patients had ICA steno-occlusion without IB infarction. The multiple logistic regression analysis showed that a more than moderate degree of steno-occlusion of the MCA was a significant factor (OR, 11.32; p = 0.006) associated with IB infarction; whereas that of the ICA was not significant (OR, 2.19; p = 0.298). Conclusion: The results of this study suggest that IB infarctions were associated with MCA steno-occlusion. ICA disease resulting in IB infarctions would be expected to have significant MCA steno-occlusion causing hemodynamic compromise.