Cardiovascular Management in Asymptomatic (Silent) Cerebral Microbleeds and Suspected Cerebral Amyloid Angiopathy.

Cerebral microbleeds (CMBs) detected on blood-sensitive magnetic resonance imaging sequences are usually a sign of an underlying cerebral small vessel disease such as sporadic cerebral amyloid angiopathy or sporadic nonamyloid small vessel pathology (eg, arteriolosclerosis). Much of the enduring interest in CMBs relates to their high prevalence (partly due to the widespread use of magnetic resonance imaging) in the context of stroke, cognitive impairment and in healthy individuals, and the clinical uncertainties created about the safety of antithrombotic medications due to their association with both future hemorrhagic and ischemic stroke. Historically, the research literature overwhelmingly emphasized the future hemorrhagic risk associated with CMBs, potentially leading to unnecessary withholding of treatments proven effective at preventing thrombosis, such as anticoagulants in patients with atrial fibrillation who happened to have some microbleeds. The lack of strong guidelines in this area contributes to wide variation in clinical practice. In this article, we critically review and discuss the implications of silent CMBs and cortical superficial siderosis (ie, without symptomatic intracerebral hemorrhage) in different clinical settings: the general population, patients with ischemic stroke, and the memory clinic. Emerging evidence, albeit not from randomized controlled trials, suggests that in most patients, CMBs alone should not prevent the use of antithrombotics or anticoagulants for stroke prevention, when they are otherwise indicated. Where possible, we provide specific suggestions for clinical care grounded in both the limited available literature and our personal clinical practice.

Uncommon Causes of Nontraumatic Intracerebral Hemorrhage.

Nontraumatic intracerebral hemorrhage is an important health issue. Although common causes such as hypertension and cerebral amyloid angiopathy predominantly affect the elderly, there exists a spectrum of uncommon etiologies that contribute to the overall incidence of intracerebral hemorrhage. The identification of these rare causes is essential for targeted clinical management, informed prognostication, and strategic secondary prevention where relevant. This topical review explores the uncommon intracerebral hemorrhage causes and provides practical clues for their clinical and imaging identification. By expanding the clinician's differential diagnosis, this review aims to bridge the gap between standard intracerebral hemorrhage classification systems and the nuanced reality of clinical practice.

A Causal Classification System for Intracerebral Hemorrhage Subtypes.

OBJECTIVE: Determining the underlying causes of intracerebral hemorrhage (ICH) is of major importance, because risk factors, prognosis, and management differ by ICH subtype. We developed a new causal CLASsification system for ICH Subtypes, termed CLAS-ICH, based on recent advances in neuroimaging. METHODS: CLAS-ICH defines 5 ICH subtypes: arteriolosclerosis, cerebral amyloid angiopathy, mixed small vessel disease (SVD), other rare forms of SVD (genetic SVD and others), and secondary causes (macrovascular causes, tumor, and other rare causes). Every patient is scored in each category according to the level of diagnostic evidence: (1) well-defined ICH subtype; (2) possible underlying disease; and (0) no evidence of the disease. We evaluated CLAS-ICH in a derivation cohort of 113 patients with ICH from Massachusetts General Hospital, Boston, USA, and in a derivation cohort of 203 patients from Inselspital, Bern, Switzerland. RESULTS: In the derivation cohort, a well-defined ICH subtype could be identified in 74 (65.5%) patients, including 24 (21.2%) with arteriolosclerosis, 23 (20.4%) with cerebral amyloid angiopathy, 18 (15.9%) with mixed SVD, and 9 (8.0%) with a secondary cause. One or more possible causes were identified in 42 (37.2%) patients. Interobserver agreement was excellent for each category (kappa value ranging from 0.86 to 1.00). Despite substantial differences in imaging modalities, we obtained similar results in the validation cohort. INTERPRETATION: CLAS-ICH is a simple and reliable classification system for ICH subtyping, that captures overlap between causes and the level of diagnostic evidence. CLAS-ICH may guide clinicians to identify ICH causes, and improve ICH classification in multicenter studies. ANN NEUROL 2023;93:16-28.

Using Noncontrast Computed Tomography to Improve Prediction of Intracerebral Hemorrhage Expansion.

BACKGROUND: Noncontrast computed tomography hypodensities are a validated predictor of hematoma expansion (HE) in intracerebral hemorrhage and a possible alternative to the computed tomography angiography (CTA) spot sign but their added value to available prediction models remains unclear. We investigated whether the inclusion of hypodensities improves prediction of HE and compared their added value over the spot sign. METHODS: Retrospective analysis of patients admitted for primary spontaneous intracerebral hemorrhage at the following 8 university hospitals in Boston, US (1994-2015, prospective), Hamilton, Canada (2010-2016, retrospective), Berlin, Germany (2014-2019, retrospective), Chongqing, China (2011-2015, retrospective), Pavia, Italy (2017-2019, prospective), Ferrara, Italy (2010-2019, retrospective), Brescia, Italy (2020-2021, retrospective), and Bologna, Italy (2015-2019, retrospective). Predictors of HE (hematoma growth >6 mL and/or >33% from baseline to follow-up imaging) were explored with logistic regression. We compared the discrimination of a simple prediction model for HE based on 4 predictors (antitplatelet and anticoagulant treatment, baseline intracerebral hemorrhage volume, and onset-to-imaging time) before and after the inclusion of noncontrast computed tomography hypodensities, using receiver operating characteristic curve and De Long test for area under the curve comparison. RESULTS: A total of 2465 subjects were included, of whom 664 (26.9%) had HE and 1085 (44.0%) had hypodensities. Hypodensities were independently associated with HE after adjustment for confounders in logistic regression (odds ratio, 3.11 [95% CI, 2.55-3.80]; P<0.001). The inclusion of noncontrast computed tomography hypodensities improved the discrimination of the 4 predictors model (area under the curve, 0.67 [95% CI, 0.64-0.69] versus 0.71 [95% CI, 0.69-0.74]; P=0.025). In the subgroup of patients with a CTA available (n=895, 36.3%), the added value of hypodensities remained statistically significant (area under the curve, 0.68 [95% CI, 0.64-0.73] versus 0.74 [95% CI, 0.70-0.78]; P=0.041) whereas the addition of the CTA spot sign did not provide significant discrimination improvement (area under the curve, 0.74 [95% CI, 0.70-0.78]). CONCLUSIONS: Noncontrast computed tomography hypodensities provided a significant added value in the prediction of HE and appear a valuable alternative to the CTA spot sign. Our findings might inform future studies and suggest the possibility to stratify the risk of HE with good discrimination without CTA.

Peak Width of Skeletonized Mean Diffusivity: A Neuroimaging Marker for White Matter Injury.

A leading cause of white matter (WM) injury in older individuals is cerebral small vessel disease (SVD). Cerebral SVD is the most prevalent vascular contributor to cognitive impairment and dementia. Therapeutic progress for cerebral SVD and other WM disorders depends on the development and validation of neuroimaging markers suitable as outcome measures in future interventional trials. Diffusion-tensor imaging (DTI) is one of the best-suited MRI techniques for assessing the extent of WM damage in the brain. But the optimal method to analyze individual DTI data remains hindered by labor-intensive and time-consuming processes. Peak width of skeletonized mean diffusivity (PSMD), a recently developed fast, fully automated DTI marker, was designed to quantify the WM damage secondary to cerebral SVD and reflect related cognitive impairment. Despite its promising results, knowledge about PSMD is still limited in the radiologic community. This focused review provides an overview of the technical details of PSMD while synthesizing the available data on its clinical and neuroimaging associations. From a critical expert viewpoint, the authors discuss the limitations of PSMD and its current validation status as a neuroimaging marker for vascular cognitive impairment. Finally, they point out the gaps to be addressed to further advance the field.

Association of Apolipoprotein E ɛ4 Allele with Enlarged Perivascular Spaces.

OBJECTIVE: Enlarged perivascular spaces have emerged as markers of cerebral small vessel disease and are linked to perivascular drainage dysfunction. The apolipoprotein E-ɛ4 (APOE-ɛ4) allele is the strongest genetic risk factor for cerebral amyloid angiopathy and Alzheimer's neuropathology, but the underlying mechanisms remain unclear. We studied the relationship between APOE-ɛ4 and the topography and burden of enlarged perivascular spaces to elucidate underlying mechanisms between APOE-ɛ4 and adverse clinical outcomes. METHODS: We included 3,564 Framingham Heart Study participants with available genotypes and magnetic resonance imaging. Enlarged perivascular spaces in the basal ganglia and centrum semiovale were rated using a validated scale. We related APOE-ɛ4 allele presence to high burden of enlarged perivascular spaces in each region and a mixed score reflecting high burden in both regions using multivariable logistic regression. Exploratory analyses incorporated presence of cerebral microbleeds and assessed effect modification by hypertension. RESULTS: Mean age was 60.7 years (SD = 14.6), 1,644 (46.1%) were men, 1,486 (41.8%) were hypertensive, and 836 (23.5%) participants were APOE-ɛ4 carriers. APOE-ɛ4 was associated with high burden of enlarged perivascular spaces in the centrum semiovale (odds ratio [OR] = 1.45, 95% confidence interval [CI] = 1.16, 1.81) and mixed regions (OR = 1.37, 95% CI = 1.11, 1.68). Associations were slightly stronger in hypertensive subjects. INTERPRETATION: The APOE-ɛ4 allele plays a modest role in the burden of enlarged perivascular spaces in the centrum semiovale. Further studies are needed to clarify the underlying small vessel disease type in community-dwelling individuals with predominant centrum semiovale enlarged perivascular spaces, which may be hypertensive angiopathy in our sample. ANN NEUROL 2022;92:23-31.

Cerebral Small Vessel Disease Burden: An Independent Biomarker for Anomia Treatment Responsiveness in Chronic Stroke Patients With Aphasia.

OBJECTIVE: To determine whether MRI-based cerebral small vessel disease (cSVD) burden predicts treatment-induced aphasia recovery in chronic stroke patients above and beyond initial aphasia severity and stroke-lesion volume. DESIGN: Retrospective. Four cSVD neuroimaging markers were rated using validated visual scales: white matter hyperintensities, enlarged perivascular spaces, lacunes, and global cortical atrophy. We also calculated a cSVD total score. We employed linear regression models to model treatment response as a function of cSVD burden. We also ran correlation analyses to determine the association among cSVD burden and pre-treatment linguistic and non-linguistic cognition. SETTING: Research clinic. PARTICIPANTS: The study includes data from 30 chronic stroke patients with aphasia who received treatment for word finding difficulties and completed additional pre-treatment neuroimaging and behavioral assessments (N=30). INTERVENTIONS: 120-minute sessions of anomia treatment 2 times per week for up to 12 weeks. MAIN OUTCOME MEASURES: Change in accuracy on the treatment probes measured as a percentage (ie, change in accuracy percentage score=post-treatment accuracy percentage minus pre-treatment accuracy percentage). RESULTS: Baseline cSVD burden predicted response to anomia treatment independently from demographic and stroke-related factors. Patients with lower cSVD burden exhibited enhanced rehabilitation response compared with those with higher cSVD burden (ß=-6.816e-02, P=.019). cSVD burden was highly associated with nonverbal executive function at baseline (r=-0.49, P=.005): patients with lower cSVD burden exhibited higher performance on nonverbal executive function tasks compared with participants with higher cSVD burden. No association was observed among cSVD burden and performance on language tasks at the baseline. CONCLUSIONS: cSVD, a marker of brain reserve and a robust risk factor for post-stroke dementia, may be used as a biomarker for distinguishing patients who are more likely to respond to anomia therapy from those who are less likely to do so and for individualizing treatment parameters (eg, targeting both linguistic and nonlinguistic cognition in severe cSVD).

Clinical Diagnosis of Probable Cerebral Amyloid Angiopathy: Diagnostic Accuracy Meta-Analysis of the Boston Criteria.

BACKGROUND: The Boston criteria are used widely for the noninvasive diagnosis of sporadic cerebral amyloid angiopathy (CAA) and hence clinical decision-making, as well as research in the field. Yet, their exact diagnostic accuracy and validity remain (paradoxically) poorly studied. We performed a meta-analysis to synthesize evidence on the value and accuracy of the Boston criteria in diagnosing probable CAA patients. METHODS: In a systematic literature search, we identified studies with extractable data relevant for sensitivity and specificity of probable CAA diagnosis per the magnetic resonance imaging Boston criteria and neuropathological CAA verification. We included studies that have classified patients according to any version of the Boston criteria, based on available brain magnetic resonance imaging blood-sensitive sequences (index test) and had neuropathologic evaluation for CAA presence from brain tissue samples (diagnostic reference standard). Using a hierarchical (multilevel) logistic regression model, we calculated pooled diagnostic test accuracy for probable CAA diagnosis. RESULTS: Seven studies, including 193 patients, 121 with neuropathologically verified CAA versus 72 non-CAA based on neuropathology definition, were included in the meta-analysis. The studies were of low-to-moderate quality and varied in several methodological aspects. The overall pooled sensitivity for probable CAA diagnosis was 66.7% (95% CI, 45.9%-82.6%) and specificity was 88.2% (95% CI, 68.5%-96.3%). A predefined subgroup analysis of 4 studies on Boston criteria v.1.0 (n=151) demonstrated a pooled sensitivity and specificity of 60% (95% CI, 45.1%-72.9%) and 93.1% (95% CI, 81.8%-97.6%), respectively. Five studies had data on Boston criteria v.1.5 (n=123): the pooled sensitivity and specificity for probable CAA diagnosis was 73.1% (95% CI, 45%-90.1%) and 86% (95% CI, 41.4%-98.1%), respectively. CONCLUSIONS: The Boston criteria v.1.0 and v.1.5 appear to have moderate-to-good diagnostic accuracy for probable CAA in symptomatic patients, with high specificity but low-to-moderate sensitivity. Data are based on limited retrospective studies of overall low quality and at high risk of bias.

Vessels Sing Their ARIAs: The Role of Vascular Amyloid in the Age of Aducanumab.

We review the implications of the recently approved aducanumab amyloid-ß immunotherapy for treating Alzheimer disease with comorbid cerebral amyloid angiopathy. In clinical trials, amyloid-ß immunotherapy has been associated with a high rate of amyloid-related imaging abnormalities, potentially driven by coexisting cerebral amyloid angiopathy. Therefore, immunotherapy's efficacy in patients may be modified by coexisting cerebrovascular pathology. We discuss the contributions of cerebral amyloid angiopathy on the development of amyloid-related imaging abnormalities and propose strategies to identify cerebral amyloid angiopathy in patients considered for immunotherapy.

Cerebral Small Vessel Disease and Depression Among Intracerebral Hemorrhage Survivors.

BACKGROUND AND PURPOSE: Intracerebral hemorrhage (ICH) is an acute manifestation of cerebral small vessel disease (CSVD), usually cerebral amyloid angiopathy or hypertensive arteriopathy. CSVD-related imaging findings are associated with increased depression incidence in the general population. Neuroimaging may, therefore, provide insight on depression risk among ICH survivors. We sought to determine whether CSVD CT and magnetic resonance imaging markers are associated with depression risk (before and after ICH), depression remission, and effectiveness of antidepressant treatment. METHODS: We analyzed data from the single-center longitudinal ICH study conducted at Massachusetts General Hospital. Participants underwent CT and magnetic resonance imaging imaging and were followed longitudinally. We extracted information for neuroimaging markers of CSVD subtype and severity. Outcomes of interest included pre-ICH depression, new-onset depression after ICH, resolution of depressive symptoms, and response to antidepressant treatment. RESULTS: We followed 612 ICH survivors for a median of 47.2 months. Multiple CSVD-related markers were associated with depression risk. Survivors of cerebral amyloid angiopathy-related lobar ICH were more likely to be diagnosed with depression before ICH (odds ratio, 1.68 [95% CI, 1.14-2.48]) and after ICH (sub-hazard ratio, 1.52 [95% CI, 1.12-2.07]), less likely to achieve remission of depressive symptoms (sub-hazard ratio, 0.69 [95% CI, 0.51-0.94]), and to benefit from antidepressant therapy (P=0.041). Cerebral amyloid angiopathy disease burden on magnetic resonance imaging was associated with depression incidence and treatment resistance (interaction P=0.037), whereas hypertensive arteriopathy disease burden was only associated with depression incidence after ICH. CONCLUSIONS: CSVD severity is associated with depression diagnosis, both before and after ICH. Cerebral amyloid angiopathy-related ICH survivors are more likely to experience depression (both before and after ICH) than patients diagnosed with hypertensive arteriopathy-related ICH, and more likely to report persistent depressive symptoms and display resistance to antidepressant treatment.

Latent profile analysis of cognitive decline and depressive symptoms after intracerebral hemorrhage.

BACKGROUND: Cognitive impairment and depressive symptoms are highly prevalent after Intracerebral Hemorrhage (ICH). We leveraged Latent Profile Analysis (LPA) to identify profiles for cognitive decline and depression onset after ICH. We also investigated differences in clinical, genetic and neuroimaging characteristics across patients' profiles. METHODS: We analyzed data from the ICH study conducted at Massachusetts General Hospital between January 1998 and December 2019. We collected information from electronical health records, follow-up interviews, CT and MRI imaging, and APOE genotype. We conducted LPA and multinomial logistic regression analyses to: 1) identify distinct profiles for cognitive decline and depression onset after ICH; 2) identify clinical, neuroimaging and genetic factors predicting individuals' likelihood to express a specific profile. RESULTS: We followed 784 ICH survivors for a median of 45.8 months. We identified four distinct profiles in cognitive and depressive symptoms after ICH: low depression and dementia risk, early-onset depression and dementia, late-onset depression and dementia, high depression with low dementia risk. Cerebral small vessel disease severity and APOE genotype were specifically associated with the late-onset profile (both p < 0.05). Acute hematoma characteristics (size, intraventricular extension) and functional disability were specifically associated with the early-onset profile (all p < 0.05). CONCLUSION: We identified four distinct profiles for cognitive and depressive symptoms after ICH, each displaying specific associations with individual patients' clinical, genetic and neuroimaging data. These associations reflect separate biological mechanisms influencing dementia and depression risk after ICH. Our findings support employing LPA in future ICH studies, and is likely applicable to stroke survivors at large.

Neuropathological correlates of cortical superficial siderosis in cerebral amyloid angiopathy.

Cortical superficial siderosis is an established haemorrhagic neuroimaging marker of cerebral amyloid angiopathy. In fact, cortical superficial siderosis is emerging as a strong independent risk factor for future lobar intracerebral haemorrhage. However, the underlying neuropathological correlates and pathophysiological mechanisms of cortical superficial siderosis remain elusive. Here we use an in vivo MRI, ex vivo MRI, histopathology approach to assess the neuropathological correlates and vascular pathology underlying cortical superficial siderosis. Fourteen autopsy cases with cerebral amyloid angiopathy (mean age at death 73 years, nine males) and three controls (mean age at death 91 years, one male) were included in the study. Intact formalin-fixed cerebral hemispheres were scanned on a 3 T MRI scanner. Cortical superficial siderosis was assessed on ex vivo gradient echo and turbo spin echo MRI sequences and compared to findings on available in vivo MRI. Subsequently, 11 representative areas in four cases with available in vivo MRI scans were sampled for histopathological verification of MRI-defined cortical superficial siderosis. In addition, samples were taken from predefined standard areas of the brain, blinded to MRI findings. Serial sections were stained for haematoxylin and eosin and Perls' Prussian blue, and immunohistochemistry was performed against amyloid-ß and GFAP. Cortical superficial siderosis was present on ex vivo MRI in 8/14 cases (57%) and 0/3 controls (P = 0.072). Histopathologically, cortical superficial siderosis corresponded to iron-positive haemosiderin deposits in the subarachnoid space and superficial cortical layers, indicative of chronic bleeding events originating from the leptomeningeal vessels. Increased severity of cortical superficial siderosis was associated with upregulation of reactive astrocytes. Next, cortical superficial siderosis was assessed on a total of 65 Perls'-stained sections from MRI-targeted and untargeted sampling combined in cerebral amyloid angiopathy cases. Moderate-to-severe cortical superficial siderosis was associated with concentric splitting of the vessel wall (an advanced form of cerebral amyloid angiopathy-related vascular damage) in leptomeningeal vessels (P < 0.0001), but reduced cerebral amyloid angiopathy severity in cortical vessels (P = 0.048). In terms of secondary tissue injury, moderate-to-severe cortical superficial siderosis was associated with the presence of microinfarcts (P = 0.025), though not microbleeds (P = 0.973). Collectively, these data suggest that cortical superficial siderosis on MRI corresponds to iron-positive deposits in the superficial cortical layers, representing the chronic manifestation of bleeding episodes from leptomeningeal vessels. Cortical superficial siderosis appears to be the result of predominantly advanced cerebral amyloid angiopathy of the leptomeningeal vessels and may trigger secondary ischaemic injury in affected areas.

Combining Imaging and Genetics to Predict Recurrence of Anticoagulation-Associated Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: For survivors of oral anticoagulation therapy (OAT)-associated intracerebral hemorrhage (OAT-ICH) who are at high risk for thromboembolism, the benefits of OAT resumption must be weighed against increased risk of recurrent hemorrhagic stroke. The ε2/ε4 alleles of the apolipoprotein E (APOE) gene, MRI-defined cortical superficial siderosis, and cerebral microbleeds are the most potent risk factors for recurrent ICH. We sought to determine whether combining MRI markers and APOE genotype could have clinical impact by identifying ICH survivors in whom the risks of OAT resumption are highest. METHODS: Joint analysis of data from 2 longitudinal cohort studies of OAT-ICH survivors: (1) MGH-ICH study (Massachusetts General Hospital ICH) and (2) longitudinal component of the ERICH study (Ethnic/Racial Variations of Intracerebral Hemorrhage). We evaluated whether MRI markers and APOE genotype predict ICH recurrence. We then developed and validated a combined APOE-MRI classification scheme to predict ICH recurrence, using Classification and Regression Tree analysis. RESULTS: Cortical superficial siderosis, cerebral microbleed, and APOE ε2/ε4 variants were independently associated with ICH recurrence after OAT-ICH (all P<0.05). Combining APOE genotype and MRI data resulted in improved prediction of ICH recurrence (Harrell C: 0.79 versus 0.55 for clinical data alone, P=0.033). In the MGH (training) data set, CSS, cerebral microbleed, and APOE ε2/ε4 stratified likelihood of ICH recurrence into high-, medium-, and low-risk categories. In the ERICH (validation) data set, yearly ICH recurrence rates for high-, medium-, and low-risk individuals were 6.6%, 2.5%, and 0.9%, respectively, with overall area under the curve of 0.91 for prediction of recurrent ICH. CONCLUSIONS: Combining MRI and APOE genotype stratifies likelihood of ICH recurrence into high, medium, and low risk. If confirmed in prospective studies, this combined APOE-MRI classification scheme may prove useful for selecting individuals for OAT resumption after ICH.

Standards for Detecting, Interpreting, and Reporting Noncontrast Computed Tomographic Markers of Intracerebral Hemorrhage Expansion.

Significant hematoma expansion (HE) affects one-fifth of people within 24 hours after acute intracerebral hemorrhage (ICH), and its prevention is an appealing treatment target. Although the computed tomography (CT)-angiography spot sign predicts HE, only a minority of ICH patients receive contrast injection. Conversely, noncontrast CT (NCCT) is used to diagnose nearly all ICH, so NCCT markers represent a widely available alternative for prediction of HE. However, different NCCT signs describe similar features, with lack of consensus on the optimal image acquisition protocol, assessment, terminology, and diagnostic criteria. In this review, we propose practical guidelines for detecting, interpreting, and reporting NCCT predictors of HE. ANN NEUROL 2019;86:480-492.

Discovering the Italian phenotype of cerebral amyloid angiopathy (CAA): the SENECA project.

Cerebral amyloid angiopathy (CAA) is one of the major types of cerebral small vessel disease, and a leading cause of spontaneous intracerebral hemorrhage and cognitive decline in elderly patients. Although increasingly detected, a number of aspects including the pathophysiology, the clinical and neuroradiological phenotype, and the disease course are still under investigation. The incomplete knowledge of the disease limits the implementation of evidence-based guidelines on patient's clinical management and the development of treatments able to prevent or reduce disease progression. The SENECA (SEarchiNg biomarkErs of Cerebral Angiopathy) project is the first Italian multicenter cohort study aimed at better defining the disease natural history and identifying clinical and neuroradiological markers of disease progression. By a multidisciplinary approach and the collection of a large and well-phenotyped series and biorepository of CAA patients, the study is ultimately expected to improve the diagnosis and the knowledge of CAA pathophysiological mechanisms.

Cerebral Small Vessel Diseases and Sleep Related Strokes.

BACKGROUND AND PURPOSE: Sleep related Stroke (SRS) is common and has been associated with cerebral small vessel diseases (SVD) in ischemic strokes (ISs). We tested the hypothesis that SRS is associated with SVD in both ischemic and hemorrhagic stroke. METHODS: Prospectively collected data from patients consecutively enrolled after intracerebral hemorrhage (ICH) related to SVD or after IS were analyzed. Symptom onset was recorded as SRS versus awake. Each ICH was grouped according to lobar and deep locations. The IS cohort was etiologically characterized based on the Causative Classification of Stroke system. Frequencies of SRS within and between ICH and IS cohorts as well as its associations (etiology, risk factors) were analyzed. RESULTS: We analyzed 1812 IS (mean age 67.9 years ± 15.9 years, 46.4% female) and 1038 ICH patients (mean age 72.5 years ± 13.0 years, 45.4% female). SRS was significantly more common among SVD-related ICH patients (n = 276, 26.6%) when compared to all IS (n = 363, 20.0%, P < .001) and in both, small artery occlusion (SAO) related IS and lobar ICH within the respective IS and ICH cohorts (16.3% SRS versus 9.1% awake for SAO within all IS, P < .001; and 57.1% SRS versus 47.7% awake for lobar bleeds within all ICH, P = .008). These associations remained significant after controlling for age, sex and risk factors. CONCLUSIONS: SRS was associated with SVD. The SAO etiology and cerebral amyloid angiopathy related lobar ICH suggest that the presence of SVD can interact with sleep or arousal related hemodynamic changes to cause ischemic and hemorrhagic stroke.

Cortical Superficial Siderosis Evolution.

Background and Purpose- We investigated cortical superficial siderosis (cSS) progression and its clinical relevance for incident lobar intracerebral hemorrhage (ICH) risk, in probable cerebral amyloid angiopathy presenting with neurological symptoms and without ICH at baseline. Methods- Consecutive patients meeting modified Boston criteria for probable cerebral amyloid angiopathy from a single-center cohort who underwent magnetic resonance imaging (MRI) at baseline and during follow-up were analyzed. cSS progression was assessed by comparison of the baseline and follow-up images. Patients were followed prospectively for incident symptomatic ICH. cSS progression and first-ever ICH risk were investigated in Cox proportional hazard models adjusting for confounders. Results- The cohort included 118 probable cerebral amyloid angiopathy patients: 72 (61%) presented with transient focal neurological episodes and 46 (39%) with cognitive complaints prompting the baseline MRI investigation. Fifty-two patients (44.1%) had cSS at baseline. During a median scan interval of 2.2 years (interquartile range, 1.2-4.4 years) between the baseline (ie, first) MRI and the latest MRI, cSS progression was detected in 33 (28%) patients. In multivariable logistic regression, baseline cSS presence (odds ratio, 4.04; 95% CI, 1.53-10.70; P=0.005), especially disseminated cSS (odds ratio, 9.12; 95% CI, 2.85-29.18; P<0.0001) and appearance of new lobar microbleeds (odds ratio, 4.24; 95% CI, 1.29-13.9; P=0.017) were independent predictors of cSS progression. For patients without an ICH during the interscan interval (n=105) and subsequent follow-up (median postfinal MRI time, 1.34; interquartile range, 0.3-3 years), cSS progression independently predicted increased symptomatic ICH risk (hazard ratio, 3.76; 95% CI, 1.37-10.35; P=0.010). Conclusions- Our results suggest that cSS evolution may be a useful biomarker for assessing disease progression and ICH risk in cerebral amyloid angiopathy patients and a candidate biomarker for clinical studies and trials.

Cerebellar Microbleed Distribution Patterns and Cerebral Amyloid Angiopathy.

Background and Purpose- Hematoma location within the cerebellum may help identify the dominant small vessel disease type (cerebral amyloid angiopathy [CAA] versus nonamyloid small vessel disease). However, it is unknown whether this holds true for cerebral microbleeds (CMBs) within the cerebellum. We tested the hypothesis that cerebellar CMBs restricted to the cortex and vermis (defined as superficial regions) are associated with clinically diagnosed and pathology-verified CAA. Methods- Three hundred and seven consecutive spontaneous intracerebral hemorrhage (ICH) patients with a baseline magnetic resonance imaging that included susceptibility-weighted imaging or angiography were enrolled. Using a topographical template, cerebellar CMB patterns were defined as strictly superficial versus deep (cerebellar gray nuclei and white matter) or mixed (both regions involved). Thirty-six ICH patients with cerebellar CMBs and neuropathology data available were evaluated for the presence of CAA. Results- One hundred and thirty-five (44%) ICH patients had CMBs in the cerebellum. In the patient group with cerebellar CMBs, 85 (63%) showed a superficial pattern, and 50 (37%) had a deep/mixed pattern. Strictly superficial cerebellar CMBs were independently associated with a supratentorial pattern of probable CAA-ICH according to the Boston criteria (odds ratio, 1.6; CI, 1.03-2.5) and deep/mixed cerebellar CMBs with a pattern of deep/mixed ICH (odds ratio, 1.8; CI, 1.2-2.7). Pathologically verified CAA was present in 23 of 24 (96%) patients with superficial cerebellar CMBs versus 3 of 12 (25%) patients with deep/mixed cerebellar CMBs ( P<0.001). Conclusions- In ICH patients, cerebellar CMBs are relatively common and often restricted to superficial regions. A strictly superficial distribution of cerebellar CMBs is associated with clinically diagnosed and pathologically verified CAA.

Clinical significance of amyloid ß positivity in patients with probable cerebral amyloid angiopathy markers.

PURPOSE: We investigated the frequency and clinical significance of amyloid ß (Aß) positivity on PET in patients with cerebral amyloid angiopathy (CAA). METHODS: We recruited 65 patients who met the modified Boston criteria for probable CAA. All underwent amyloid PET, MRI, APOE genotyping and neuropsychological testing, and we obtained information on MRI markers of CAA and ischemic cerebral small-vessel disease (CSVD). We investigated the CAA/ischemic CSVD burden and APOE genotypes in relation to Aß positivity and investigated the effect of Aß positivity on longitudinal cognitive decline. RESULTS: Among the 65 CAA patients, 43 (66.2%) showed Aß PET positivity (Aß+). Patients with Aß+ CAA had more lobar microbleeds (median 9, interquartile range 2-41, vs. 3, 2-8; P = 0.045) and a higher frequency of cortical superficial siderosis (34.9% vs. 9.1%; P = 0.025), while patients with Aß- CAA had more lacunes (1, 0-2, vs. 0, 0-1; P = 0.029) and a higher frequency of severe white matter hyperintensities (45.5% vs. 20.9%; P = 0.040). The frequency of ε4 carriers was higher in Aß+ patients (57.1%) than in Aß- patients (18.2%; P = 0.003), while the frequency of ε2 carriers did not differ between the two groups. Finally, Aß positivity was associated with faster decline in multiple cognitive domains including language (P < 0.001), visuospatial function (P < 0.001), and verbal memory (P < 0.001) in linear mixed effects models. CONCLUSION: Our findings suggest that a significant proportion of patients with probable CAA in a memory clinic are Aß- on PET. Aß positivity in CAA patients is associated with a distinct pattern of CSVD biomarker expression, and a worse cognitive trajectory. Aß positivity has clinical relevance in CAA and might represent either advanced CAA or additional Alzheimer's disease neuropathological changes.