Idiopathic primary intraventricular hemorrhage and cerebral small vessel disease

BACKGROUND

Although primary intraventricular hemorrhage is frequently due to trauma or vascular lesions, the etiology of idiopathic primary intraventricular hemorrhage (IP-IVH) is not defined.

AIMS

Herein, we test the hypothesis that cerebral small vessel diseases (cSVD) including hypertensive cSVD (HTN-cSVD) and cerebral amyloid angiopathy are associated with IP-IVH.

METHODS

Brain magnetic resonance imaging from consecutive patients (January 2011 to September 2019) with non-traumatic intracerebral hemorrhage from a single referral center were reviewed for the presence of HTN-cSVD (defined by strictly deep or mixed-location intracerebral hemorrhage/cerebral microbleeds) and cerebral amyloid angiopathy (applying modified Boston criteria).

RESULTS

Forty-six (4%) out of 1276 patients were identified as having IP-IVH. Among these, the mean age was 74.4 ± 12.2 years and 18 (39%) were females. Forty (87%) had hypertension, and the mean initial blood pressure was 169.2 ± 40.4/88.8 ± 22.2 mmHg. Of the 35 (76%) patients who received a brain magnetic resonance imaging, two (6%) fulfilled the modified Boston criteria for possible cerebral amyloid angiopathy and 10 (29%) for probable cerebral amyloid angiopathy. Probable cerebral amyloid angiopathy was found at a similar frequency when comparing IP-IVH patients to the remaining patients with primary intraparenchymal hemorrhage (P-IPH) (27%, p = 0.85). Furthermore, imaging evidence for HTN-cSVD was found in 8 (24%) patients with IP-IVH compared to 209 (28%, p = 0.52) patients with P-IPH.

CONCLUSIONS

Among IP-IVH patients, cerebral amyloid angiopathy was found in approximately one-third of patients, whereas HTN-cSVD was detected in 23%-both similar rates to P-IPH patients. Our results suggest that both cSVD subtypes may be associated with IP-IVH.

Decreased Basal Ganglia Volume in Cerebral Amyloid Angiopathy

Background and Purpose

Cerebral amyloid angiopathy (CAA) is a common pathology of the leptomeningeal and cortical small vessels associated with hemorrhagic and non-hemorrhagic brain injury. Given previous evidence for CAA-related loss of cortical thickness and white matter volume, we hypothesized that CAA might also cause tissue loss in the basal ganglia.

Methods

We compared basal ganglia volumes expressed as a percentage of total intracranial volume (pBGV) of non-demented patients with sporadic and hereditary CAA to age-matched healthy control (HC) and Alzheimer’s disease (AD) cohorts.

Results

Patients with sporadic CAA had lower pBGV (n=80, 1.16%±0.14%) compared to HC (n=80, 1.30%±0.13%, P<0.0001) and AD patients (n=80, 1.23%±0.11%, P=0.001). Similarly, patients with hereditary CAA demonstrated lower pBGV (n=25, 1.26%±0.17%) compared to their matched HC (n=25, 1.36%±0.15%, P=0.036). Using a measurement of normalized basal ganglia width developed for analysis of clinical-grade magnetic resonance images, we found smaller basal ganglia width in patients with CAA-related lobar intracerebral hemorrhage (ICH; n=93, 12.35±1.47) compared to age-matched patients with hypertension-related deep ICH (n=93, 13.46±1.51, P<0.0001) or HC (n=93, 15.45±1.22, P<0.0001). Within the sporadic CAA research cohort, decreased basal ganglia volume was independently correlated with greater cortical gray matter atrophy (r=0.45, P<0.0001), increased basal ganglia fractional anisotropy (r=–0.36, P=0.001), and worse performance on language processing (r=0.35, P=0.003), but not with cognitive tests of executive function or processing speed.

Conclusions

These findings suggest an independent effect of CAA on basal ganglia tissue loss, indicating a novel mechanism for CAA-related brain injury and neurologic dysfunction.

White matter atrophy in cerebral amyloid angiopathy

OBJECTIVE

We postulated that cerebral amyloid angiopathy (CAA) is associated with white matter atrophy (WMA) and that WMA can be related to cognitive changes in CAA.

METHODS

White matter volume expressed as percent of intracranial volume (pWMV) of prospectively enrolled patients without dementia diagnosed with probable CAA was compared to age-matched healthy controls (HC) and patients with Alzheimer disease (AD). Cognitive scores were also sought to understand the potential effects of WMA on cognitive function.

RESULTS

Patients with CAA (n = 72) had significantly lower pWMV (27.97% ± 2.63) when compared to age-matched HC (n = 72; mean difference [MD], 2.38%; p < 0.0001) and patients with AD (n = 72; MD, 1.57%; p < 0.0001). Differences were most pronounced in the posterior occipital regions in both comparisons. When comparisons were restricted to groups of patients with CAA but no intracerebral hemorrhage (n = 32) or hypertension (n = 32), and age-matched HC and AD, the significant differences were unaltered. Within the CAA cohort, higher age, lobar microbleed counts, and presence of hypertension were associated with lower pWMV (p = 0.0007, p = 0.031, and p = 0.003, respectively). All associations remained independent in multivariable analyses. Within the CAA cohort, higher pWMV independently correlated with better scores of executive function.

CONCLUSIONS

Patients with CAA show WMA when compared to age-matched HC and patients with AD. WMA independently correlates with the number of lobar microbleeds, a marker of CAA severity. Consistent spatial patterns of WMA especially in posterior regions might be related to CAA. The association between WMA and measures of executive function suggests that WMA might represent an important mediator of CAA-related neurologic dysfunction.

Cortical superficial siderosis progression in cerebral amyloid angiopathy: Prospective MRI study

OBJECTIVE

To investigate the prevalence, predictors, and clinical relevance of cortical superficial siderosis (cSS) progression in cerebral amyloid angiopathy (CAA).

METHODS

Consecutive patients with symptomatic CAA meeting Boston criteria in a prospective cohort underwent baseline and follow-up MRI within 1 year. cSS progression was evaluated on an ordinal scale and categorized into mild (score 1-2 = cSS extension within an already present cSS focus or appearance of 1 new cSS focus) and severe progression (score 3-4 = appearance of ≥2 new cSS foci). Binominal and ordinal multivariable logistic regression were used to determine cSS progression predictors. We investigated future lobar intracerebral hemorrhage (ICH) risk in survival analysis models.

RESULTS

We included 79 patients with CAA (mean age, 69.2 years), 56 (71%) with lobar ICH at baseline. cSS progression was detected in 23 (29%) patients: 15 (19%) patients had mild and 8 (10%) severe progression. In binominal multivariable logistic regression, ICH presence (odds ratio [OR], 7.54; 95% confidence interval [CI], 1.75-53.52; p = 0.016) and baseline cSS (OR, 10.41; 95% CI, 2.84-52.83; p = 0.001) were independent predictors of cSS progression. In similar models, presence of disseminated (but not focal) cSS at baseline (OR, 5.58; 95% CI, 1.81-19.41; p = 0.004) was an independent predictor of cSS progression. Results were similar in ordinal multivariable logistic regression models. In multivariable Cox regression analysis, severe cSS progression was independently associated with increased future ICH risk (HR, 5.90; 95% CI, 1.30-26.68; p = 0.021).

CONCLUSIONS

cSS evolution on MRI is common in patients with symptomatic CAA and might be a potential biomarker for assessing disease severity and future ICH risk. External validation of these findings is warranted.

Abstract 19: Default Mode Network Alterations in Cerebral Amyloid Angiopathy: A Resting State FMRI Study

Introduction: Cerebral amyloid angiopathy (CAA) is an established cause of intracerebral hemorrhage and vascular dysfunction leading to ischemia. Functional connectivity analysis using MRI is becoming an important tool to analyze the brain activity during resting state, the default mode network (DMN) representing the prototypical set of connections. As CAA pathology has a posterior predominance, we sought to characterize the functional connectivity of the posterior DMN at resting state in patients with CAA.

Methods: Patients with probable CAA diagnosed using Boston Criteria and healthy controls (HC) were prospectively enrolled and received high resolution 3T MRI scans including dedicated resting-state fMRI sequences. Functional seed-to-seed analyses were done using the default processing pipeline in the CONN Toolbox. Correlation maps between the established DMN and specific regions of the posterior DMN, the precuneus and posterior cingulate, were averaged within groups and compared in an ANCOVA model.

Results: Study participants consisted of 60 patients with probable CAA and 20 healthy controls [aged 69 ± 7.5 vs 72.3 ± 8 years, P = 0.108]. Seed-to-seed analysis revealed a significantly lower strength of DMN connectivity in CAA when compared to controls in the precuneus [ P = 0.009] and posterior cingulate [ P = 0.003] adjusted for age and sex (Fig 1).

Conclusion: Patients with CAA exhibited significant loss of connectivity in the posterior regions of the DMN when compared to controls. The precuneus and posterior cingulate are core regions of the DMN with reportedly high metabolic rates at rest. Disruption of these posterior DMN regions might occur due to vascular amyloid pathology that shows a predominantly posterior distribution.

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.

Cortical superficial siderosis and recurrent intracerebral hemorrhage risk in cerebral amyloid angiopathy: Large prospective cohort and preliminary meta-analysis

BACKGROUND

We aimed to investigate cortical superficial siderosis as an MRI predictor of lobar intracerebral hemorrhage (ICH) recurrence risk in cerebral amyloid angiopathy (CAA), in a large prospective MRI cohort and a systematic review.

METHODS

We analyzed a single-center MRI prospective cohort of consecutive CAA-related ICH survivors. Using Kaplan-Meier and Cox regression analyses, we investigated cortical superficial siderosis and ICH risk, adjusting for known confounders. We pooled data with eligible published cohorts in a two-stage meta-analysis using random effects models. Covariate-adjusted hazard rations (adj-HR) from pre-specified multivariable Cox proportional hazard models were used.

RESULTS

The cohort included 240 CAA-ICH survivors (cortical superficial siderosis prevalence: 36%). During a median follow-up of 2.6 years (IQR: 0.9-5.1 years) recurrent ICH occurred in 58 patients (24%). In prespecified multivariable Cox regression models, cortical superficial siderosis presence and disseminated cortical superficial siderosis were independent predictors of increased symptomatic ICH risk at follow-up (HR: 2.26; 95% CI: 1.31-3.87, p = 0.003 and HR: 3.59; 95% CI: 1.96-6.57, p < 0.0001, respectively). Three cohorts including 443 CAA-ICH patients in total were eligible for meta-analysis. During a mean follow-up of 2.5 years (range: 2-3 years) 92 patients experienced recurrent ICH (pooled risk ratio: 6.9% per year, 95% CI: 4.2%-9.7% per year). In adjusted pooled analysis, any cortical superficial siderosis and disseminated cortical superficial siderosis were the only independent predictors associated with increased lobar ICH recurrence risk (adj-HR: 2.4; 95% CI: 1.5-3.7; p < 0.0001, and adj-HR: 4.4; 95% CI: 2-9.9; p < 0.0001, respectively).

CONCLUSIONS

In CAA-ICH patients, cortical superficial siderosis presence and extent are the most important MRI prognostic risk factors for lobar ICH recurrence. These results can help guide clinical decision making in patients with CAA.

Abstract 103: Cortical tau Pathology in Cerebral Amyloid Angiopathy

Introduction: Cerebral amyloid angiopathy (CAA), a condition related to Alzheimer’s Disease, causes ischemic and hemorrhagic brain injury and contributes to cognitive impairment. Vascular amyloid, the hallmark of CAA, can be detected using amyloid PET imaging. We used selective tau imaging to understand the degree and associations of tau aggregation and deposition in patients with CAA.

Methods: Thirty-four patients with probable CAA but without cognitive impairment were prospectively enrolled. Selective tau imaging was performed using PET tracer flortaucipir (FTP) and amyloid imaging was obtained with Pittsburgh Compound B PET. Global and region of interest based (ROI) standardized uptake value ratios (SUVR) were calculated from PET acquisitions. High resolution multimodal MRIs were obtained for each patient and markers of CAA-related structural injury were quantified.

Results: The mean age ( + SD) of the patients was 69 + 6, 38% were female. Thirteen patients (38%) enrolled without intracerebral hemorrhage (ICH). Mean cortical FTP uptake was 1.18 + 0.11 (tau load, in SUVR). Five patients were tau positive based on FTP SUVR > 1.28 from a posterior cingulate cortex ROI, a previously validated method. Mean global cortical FTP uptake correlated with cortical amyloid load (r=0.37, p=0.04), centrum semiovale perivascular spaces (cs-PVS, r=0.49, p=0.004), extent of cortical superficial siderosis (cSS, r=0.44, p=0.01), and showed a trend for correlation with extent of leukoaraiosis (r=0.33, p=0.059). The associations with amyloid load and cs-PVS remained significant in multivariable models. Cortical FTP uptake was not associated with age, sex, vascular risk factors, presence of ICH or any of the CAA-related focal lesions (cerebral microbleeds, microinfarcts, lacunes), all p>0.2.

Conclusions: Our results show that many patients with CAA have some degree of cortical tau deposition, but severe tau positivity was not frequent (15%) in this cognitively normal CAA cohort, considering that 30% of healthy older adults were positive in other studies. The associations of cortical tau with brain amyloid and CAA-specific markers of global brain injury suggest that vascular amyloid might trigger tau deposition which, in turn, might increase parenchymal damage.

Acute convexity subarachnoid haemorrhage and cortical superficial siderosis in probable cerebral amyloid angiopathy without lobar haemorrhage

INTRODUCTION

Acute non-traumatic convexity subarachnoid haemorrhage (cSAH) is increasingly recognised in cerebral amyloid angiopathy (CAA). We investigated: (a) the overlap between acute cSAH and cortical superficial siderosis-a new CAA haemorrhagic imaging signature and (b) whether acute cSAH presents with particular clinical symptoms in patients with probable CAA without lobar intracerebral haemorrhage.

METHODS

MRI scans of 130 consecutive patients meeting modified Boston criteria for probable CAA were analysed for cortical superficial siderosis (focal, ≤3 sulci; disseminated, ≥4 sulci), and key small vessel disease markers. We compared clinical, imaging and cortical superficial siderosis topographical mapping data between subjects with versus without acute cSAH, using multivariable logistic regression.

RESULTS

We included 33 patients with probable CAA presenting with acute cSAH and 97 without cSAH at presentation. Patients with acute cSAH were more commonly presenting with transient focal neurological episodes (76% vs 34%; p<0.0001) compared with patients with CAA without cSAH. Patients with acute cSAH were also more often clinically presenting with transient focal neurological episodes compared with cortical superficial siderosis-positive, but cSAH-negative subjects with CAA (76% vs 30%; p<0.0001). Cortical superficial siderosis prevalence (but no other CAA severity markers) was higher among patients with cSAH versus those without, especially disseminated cortical superficial siderosis (49% vs 19%; p<0.0001). In multivariable logistic regression, cortical superficial siderosis burden (OR 5.53; 95% CI 2.82 to 10.8, p<0.0001) and transient focal neurological episodes (OR 11.7; 95% CI 2.70 to 50.6, p=0.001) were independently associated with acute cSAH.

CONCLUSIONS

This probable CAA cohort provides additional evidence for distinct disease phenotypes, determined by the presence of cSAH and cortical superficial siderosis.

Abstract TP332: Etiology, Imaging Characteristics and Outcome of Intracerebral Hemorrhage In Patients Treated With Direct Oral Anticoagulants vs. Vitamin K Antagonists: A Single Centre Experience

Introduction: Intracerebral hemorrhage (ICH) is the most feared complication of anticoagulation. Risk markers, causes, characteristics, and outcome of acute direct oral anticoagulants (DOAC) ICH are an active field of investigation. We assessed these characteristics in patients with acute DOAC-ICH vs. vitamin K antagonist-associated ICH (VKA-ICH) and non-anticoagulant ICH.

Methods: Consecutive patients admitted to our Stroke centre with acute ICH (September 2013-May 2017) were screened. Outcomes were mortality and poor functional outcome (defined as mRS≥4) at discharge. Baseline clinical/imaging variables and outcome were compared between DOAC-ICH and VKA-ICH groups. We also compared these groups to spontaneous ICH (n=395). In DOAC-ICH we reviewed the presence of potential imaging markers of high ICH risk.

Results: We included 124 patients: 20 DOAC-ICH and 104 VKA-ICH. The two groups were similar in baseline demographics and vascular risk factors. There was no difference in median baseline ICH volume in DOAC-ICH vs. VKA-ICH (median: 16.5 ml, IQR: 4.4-40.1 vs. 18.6 ml, IQR: 3.6-46.5; p=0.877). Hematoma location was more often deep/brainstem in DOAC-ICH vs. VKA-ICH (80% vs. 45% respectively; p<0.001). The discharge mortality was higher (but not significant) for DOAC-ICH vs. VKA-ICH group (50% vs. 37.5%; p=0.295). The two groups had similar rates of poor functional outcome at discharge (90% vs. 92.3%; p=0.729). Compared to spontaneous ICH, DOAC-ICH and VKN-ICH had higher mortality at discharge (27% vs. 55%; p=0.022 and 27% vs. 37%; p=0.029 respectively). Eight DOAC-ICH had brain MRIs available. 7/8 patients showed evidence of microbleeds: multiple in a mixed distribution (i.e. both deep and lobar) in 4, strictly deep in 2 and strictly lobar in one patient. Two patients had evidence of cortical superficial siderosis. All DOAC-ICH patients had white matter hyperintensities on MRI or CT, with moderate-to-severe lesions in 71%.

Conclusion: ICH volume, mortality and functional outcome are similar for DOAC-ICH and VKA-ICH, but their outcomes are worse than non-anticoagulant ICH. High ICH risk markers seem to be common on imaging in the majority of DOAC-ICH, and tend to occur in deep brain regions, a clinically relevant hypothesis-generating finding.

Abstract WP330: Resource Utilization Among Patients Transferred for Intracerebral Hemorrhage

Background: Patients with intracerebral hemorrhage (ICH) are frequently transferred between hospitals in anticipation of the need for higher level of care than locally available. We aimed to identify factors that are associated with increased resource utilization among patients with ICH transferred to a single academic hospital.

Methods: We utilized data on patients with primary ICH at urban academic hospital between 01/01/2005-12/31/2015 from a prospectively collected registry of consecutive patients. Those with trauma, aneurysm, tumor, or other types of secondary ICH were excluded. Disease severity was calculated using the ICH score at time of presentation. The primary outcome (care that may not be available at the sending hospital) was operationally defined as use of either ICU admission or surgical intervention. We used logistic regression to examine predictors of ICU stay or surgical intervention, controlling for age, sex, race/ethnicity, insurance status, anticoagulation use, and past history of stroke or ICH.

Results: During the study period, 2008 patients met inclusion criteria, 71% of whom presented as transfers. ICU stay or surgical intervention was required in 887 (44.2%). Patient requiring ICU stay or surgical intervention were younger (mean age 71 vs. 74 years, p<0.001), less often white (83.9% vs. 89.3%, p<0.001), had lower GCS (median 12 vs. 14, p<0.001), and more frequently had intraventricular hemorrhage (58.6% vs. 43.4%, p<0.001). Of the 334 with GCS of 15 and ICH score of 0, 86 had an ICU stay (25.7%), and 4 required surgery (1.1%). In multivariable regression analysis, the only significant predictors of ICU stay or surgical intervention were age>65 years (OR 0.38, 95% CI 0.21-0.69), GCS<15 (1.23, 95% CI 1.01-1.52) and ICH score>0 (OR 2.23, 95% CI 1.70-2.91).

Conclusion: Among this cohort of patients with primary ICH, those with GCS of 15 and ICH score of 0 were less likely to require ICU stay or surgical intervention. These results should be validated in a larger sample but may be valuable for hospitals considering which ICH patients should be transferred to a tertiary care center.

Mixed-location cerebral hemorrhage/microbleeds: Underlying microangiopathy and recurrence risk

OBJECTIVE

To assess the predominant type of cerebral small vessel disease (SVD) and recurrence risk in patients who present with a combination of lobar and deep intracerebral hemorrhage (ICH)/microbleed locations (mixed ICH).

METHODS

Of 391 consecutive patients with primary ICH enrolled in a prospective registry, 75 (19%) had mixed ICH. Their demographics, clinical/laboratory features, and SVD neuroimaging markers were compared to those of 191 patients with probable cerebral amyloid angiopathy (CAA-ICH) and 125 with hypertensive strictly deep microbleeds and ICH (HTN-ICH). ICH recurrence and case fatality were also analyzed.

RESULTS

Patients with mixed ICH showed a higher burden of vascular risk factors reflected by a higher rate of left ventricular hypertrophy, higher creatinine values, and more lacunes and severe basal ganglia (BG) enlarged perivascular spaces (EPVS) than patients with CAA-ICH (all p < 0.05). In multivariable models mixed ICH diagnosis was associated with higher creatinine levels (odds ratio [OR] 2.5, 95% confidence interval [CI] 1.2-5.0, p = 0.010), more lacunes (OR 3.4, 95% CI 1.7-6.8), and more severe BG EPVS (OR 5.8, 95% CI 1.7-19.7) than patients with CAA-ICH. Conversely, when patients with mixed ICH were compared to patients with HTN-ICH, they were independently associated with older age (OR 1.03, 95% CI 1.02-1.1), more lacunes (OR 2.4, 95% CI 1.1-5.3), and higher microbleed count (OR 1.6, 95% CI 1.3-2.0). Among 90-day survivors, adjusted case fatality rates were similar for all 3 categories. Annual risk of ICH recurrence was 5.1% for mixed ICH, higher than for HTN-ICH but lower than for CAA-ICH (1.6% and 10.4%, respectively).

CONCLUSIONS

Mixed ICH, commonly seen on MRI obtained during etiologic workup, appears to be driven mostly by vascular risk factors similar to HTN-ICH but demonstrates more severe parenchymal damage and higher ICH recurrence risk.

Cortical superficial siderosis multifocality in cerebral amyloid angiopathy: A prospective study

OBJECTIVE

In order to explore the mechanisms of cortical superficial siderosis (cSS) multifocality and its clinical implications for recurrent intracerebral hemorrhage (ICH) risk in patients with cerebral amyloid angiopathy (CAA), we used a new rating method that we developed specifically to evaluate cSS extent at spatially separated foci.

METHODS

Consecutive patients with CAA-related ICH according to Boston criteria from a single-center prospective cohort were analyzed. The new score that assesses cSS multifocality (total range 0-4) showed excellent interrater reliability (k = 0.87). The association of cSS with markers of CAA and acute ICH was investigated. Patients were followed prospectively for recurrent symptomatic ICH.

RESULTS

The cohort included 313 patients with CAA. Multifocal cSS prevalence was 21.1%. APOE ε2 allele prevalence was higher in patients with multifocal cSS. In probable/definite CAA, cSS multifocality was independently associated with neuroimaging markers of CAA severity, including lobar microbleeds, but not with acute ICH features, which conversely, were determinants of cSS in possible CAA. During a median follow-up of 2.6 years (interquartile range 0.9-5.1 years), the annual ICH recurrence rates per cSS scores (0-4) were 5%, 6.5%, 13.5%, 16.2%, and 26.9%, respectively. cSS multifocality (presence and spread) was the only independent predictor of increased symptomatic ICH risk (hazard ratio 3.19; 95% confidence interval 1.77-5.75; p < 0.0001).

CONCLUSIONS

The multifocality of cSS correlates with disease severity in probable CAA; therefore cSS is likely to be caused by discrete hemorrhagic foci. The new cSS scoring system might be valuable for clinicians in determining annual risk of ICH recurrence.

Hemorrhage recurrence risk factors in cerebral amyloid angiopathy: Comparative analysis of the overall small vessel disease severity score versus individual neuroimaging markers

INTRODUCTION

An MRI-based score of total small vessel disease burden (CAA-SVD-Score) in cerebral amyloid angiopathy (CAA) has been demonstrated to correlate with severity of pathologic changes. Evidence suggests that CAA-related intracerebral hemorrhage (ICH) recurrence risk is associated with specific disease imaging manifestations rather than overall severity. We compared the correlation between the CAA-SVD-Score with the risk of recurrent CAA-related lobar ICH versus the predictive role of each of its components.

METHODS

Consecutive patients with CAA-related ICH from a single-center prospective cohort were analyzed. Radiological markers of CAA related SVD damage were quantified and categorized according to the CAA-SVD-Score (0-6 points). Subjects were followed prospectively for recurrent symptomatic ICH. Adjusted Cox proportional hazards models were used to investigate associations between the CAA-SVD-Score as well as each of the individual MRI signatures of CAA and the risk of recurrent ICH.

RESULTS

In 229 CAA patients with ICH, a total of 56 recurrent ICH events occurred during a median follow-up of 2.8years [IQR 0.9-5.4years, 781 person-years). Higher CAA-SVD-Score (HR=1.26 per additional point, 95%CI [1.04-1.52], p=0.015) and older age were independently associated with higher ICH recurrence risk. Analysis of individual markers of CAA showed that CAA-SVD-Score findings were due to the independent effect of disseminated superficial siderosis (HR for disseminated cSS vs none: 2.89, 95%CI [1.47-5.5], p=0.002) and high degree of perivascular spaces enlargement (RR=3.50-95%CI [1.04-21], p=0.042).

CONCLUSION

In lobar CAA-ICH patients, higher CAA-SVD-Score does predict recurrent ICH. Amongst individual elements of the score, superficial siderosis and dilated perivascular spaces are the only markers independently associated with ICH recurrence, contributing to the evidence for distinct CAA phenotypes singled out by neuro-imaging manifestations.

Association Between Hypodensities Detected by Computed Tomography and Hematoma Expansion in Patients With Intracerebral Hemorrhage

IMPORTANCE

Hematoma expansion is a potentially modifiable predictor of poor outcome following an acute intracerebral hemorrhage (ICH). The ability to identify patients with ICH who are likeliest to experience hematoma expansion and therefore likeliest to benefit from expansion-targeted treatments remains an unmet need. Hypodensities within an ICH detected by noncontrast computed tomography (NCCT) have been suggested as a predictor of hematoma expansion.

OBJECTIVE

To determine whether hypodense regions, irrespective of their specific patterns, are associated with hematoma expansion in patients with ICH.

DESIGN, SETTING, AND PARTICIPANTS

We analyzed a large cohort of 784 patients with ICH (the development cohort; 55.6% female), examined NCCT findings for any hypodensity, and replicated our findings on a different cohort of patients (the replication cohort; 52.7% female). Baseline and follow-up NCCT data from consecutive patients with ICH presenting to a tertiary care hospital between 1994 and 2015 were retrospectively analyzed. Data analyses were performed between December 2015 and January 2016.

MAIN OUTCOMES AND MEASURES

Hypodensities were analyzed by 2 independent blinded raters. The association between hypodensities and hematoma expansion (>6 cm3 or 33% of baseline volume) was determined by multivariable logistic regression after controlling for other variables associated with hematoma expansion in univariate analyses with P ≤ .10.

RESULTS

A total of 1029 patients were included in the analysis. In the development and replication cohorts, 222 of 784 patients (28.3%) and 99 of 245 patients (40.4%; 321 of 1029 patients [31.2%]), respectively, had NCCT scans that demonstrated hypodensities at baseline (κ = 0.87 for interrater reliability). In univariate analyses, hypodensities were associated with hematoma expansion (86 of 163 patients with hematoma expansion had hypodensities [52.8%], whereas 136 of 621 patients without hematoma expansion had hypodensities [21.9%]; P < .001). The association between hypodensities and hematoma expansion remained significant (odds ratio, 3.42 [95% CI, 2.21-5.31]; P < .001) in a multivariable model; other independent predictors of hematoma expansion were a CT angiography spot sign, a shorter time to CT, warfarin use, and older age. The independent predictive value of hypodensities was again demonstrated in the replication cohort (odds ratio, 4.37 [95% CI, 2.05-9.62]; P < .001).

CONCLUSION AND RELEVANCE

Hypodensities within an acute ICH detected on an NCCT scan may predict hematoma expansion, independent of other clinical and imaging predictors. This novel marker may help clarify the mechanism of hematoma expansion and serve as a useful addition to clinical algorithms for determining the risk of and treatment stratification for hematoma expansion.

Association of Key Magnetic Resonance Imaging Markers of Cerebral Small Vessel Disease With Hematoma Volume and Expansion in Patients With Lobar and Deep Intracerebral Hemorrhage

Importance

Hematoma expansion is an important determinant of outcome in spontaneous intracerebral hemorrhage (ICH) due to small vessel disease (SVD), but the association between the severity of the underlying SVD and the extent of bleeding at the acute phase is unknown to date.

Objective

To investigate the association between key magnetic resonance imaging (MRI) markers of SVD (as per the Standards for Reporting Vascular Changes on Neuroimaging [STRIVE] guidelines) and hematoma volume and expansion in patients with lobar or deep ICH.

Design, Setting, and Participants

Analysis of data collected from 418 consecutive patients admitted with primary lobar or deep ICH to a single tertiary care medical center between January 1, 2000, and October 1, 2012. Data were analyzed on March 4, 2016. Participants were consecutive patients with computed tomographic images allowing ICH volume calculation and MRI allowing imaging markers of SVD assessment.

Main Outcomes and Measures

The ICH volumes at baseline and within 48 hours after symptom onset were measured in 418 patients with spontaneous ICH without anticoagulant therapy, and hematoma expansion was calculated. Cerebral microbleeds, cortical superficial siderosis, and white matter hyperintensity volume were assessed on MRI. The associations between these SVD markers and ICH volume, as well as hematoma expansion, were investigated using multivariable models.

Results

This study analyzed 254 patients with lobar ICH (mean [SD] age, 75 [11] years and 140 [55.1%] female) and 164 patients with deep ICH (mean [SD] age 67 [14] years and 71 [43.3%] female). The presence of cortical superficial siderosis was an independent variable associated with larger ICH volume in the lobar ICH group (odds ratio per quintile increase in final ICH volume, 1.49; 95% CI, 1.14-1.94; P = .004). In multivariable models, the absence of cerebral microbleeds was associated with larger ICH volume for both the lobar and deep ICH groups (odds ratios per quintile increase in final ICH volume, 1.41; 95% CI, 1.11-1.81; P = .006 and 1.43; 95% CI, 1.04-1.99; P = .03; respectively) and with hematoma expansion in the lobar ICH group (odds ratio, 1.70; 95% CI, 1.07-2.92; P = .04). The white matter hyperintensity volumes were not associated with either hematoma volume or expansion.

Conclusions and Relevance

In patients admitted with primary lobar or deep ICH to a single tertiary care medical center, the presence of cortical superficial siderosis was an independent variable associated with larger lobar ICH volume, and the absence of cerebral microbleeds was associated with larger lobar and deep ICHs. The absence of cerebral microbleeds was independently associated with more frequent hematoma expansion in patients with lobar ICH. We provide an analytical framework for future studies aimed at limiting hematoma expansion.

Distribution of lacunes in cerebral amyloid angiopathy and hypertensive small vessel disease

OBJECTIVE

To evaluate whether the burden of deep and lobar lacunes differs between patients with intracerebral hemorrhage (ICH) with definite/probable cerebral amyloid angiopathy (CAA) per the Boston criteria and hypertensive small vessel disease (HTN-SVD; ICH in basal ganglia, thalami, brainstem).

METHODS

We defined lobar and deep lacunes similar to the topographic distribution used for ICH and cerebral microbleeds (CMBs). We then compared their distribution between patients with CAA-ICH and those with strictly deep CMB and ICH (HTN-ICH). The independent associations of lacune location with the diagnosis of CAA-ICH and HTN-ICH were evaluated with multivariable models. The relationship between lobar lacunes and white matter hyperintensity (WMH) volume was evaluated by means of partial correlation analyses adjusted for age and a validated visual scale.

RESULTS

In our final cohort of 316 patients with ICH, lacunes were frequent (24.7%), with similar rates in 191 patients with CAA and 125 with HTN-ICH (23% vs 27.2%, p = 0.4). Lobar lacunes were more commonly present in CAA (20.4% vs 5.7%, p < 0.001), while deep lacunes were more frequent in HTN-ICH (15.2% vs 2.1%, p < 0.001). After correction for demographics and clinical and neuroimaging markers of SVD, lobar lacunes were associated with CAA (p = 0.003) and deep lacunes with HTN-ICH (p < 0.001). Lobar lacunes in 80% of the cases were at least in contact with WMH, and after adjustment for age, they were highly correlated to WMH volume (r = 0.42, p < 0.001).

CONCLUSIONS

Lobar lacunes are associated with CAA, whereas deep lacunes are more frequent in HTN-SVD. Lobar lacunes seem to have a close relationship with WMH, suggesting a possible common origin.

Cortical superficial siderosis and first-ever cerebral hemorrhage in cerebral amyloid angiopathy

OBJECTIVE

To investigate whether cortical superficial siderosis (cSS) is associated with increased risk of future first-ever symptomatic lobar intracerebral hemorrhage (ICH) in patients with cerebral amyloid angiopathy (CAA) presenting with neurologic symptoms and without ICH.

METHODS

Consecutive patients meeting modified Boston criteria for probable CAA in the absence of ICH from a single-center cohort were analyzed. cSS and other small vessel disease MRI markers were assessed according to recent consensus recommendations. Patients were followed prospectively for future incident symptomatic lobar ICH. Prespecified Cox proportional hazard models were used to investigate cSS and first-ever lobar ICH risk adjusting for potential confounders.

RESULTS

The cohort included 236 patients with probable CAA without lobar ICH at baseline. cSS prevalence was 34%. During a median follow-up of 3.26 years (interquartile range 1.42-5.50 years), 27 of 236 patients (11.4%) experienced a first-ever symptomatic lobar ICH. cSS was a predictor of time until first ICH (p = 0.0007, log-rank test). The risk of symptomatic ICH at 5 years of follow-up was 19% (95% confidence interval [CI] 11%-32%) for patients with cSS at baseline vs 6% (95% CI 3%-12%) for patients without cSS. In multivariable Cox regression models, cSS presence was the only independent predictor of increased symptomatic ICH risk during follow-up (HR 4.04; 95% CI 1.73-9.44, p = 0.001), after adjusting for age, lobar cerebral microbleeds burden, and white matter hyperintensities.

CONCLUSIONS

cSS is consistently associated with an increased risk of future lobar ICH in CAA with potentially important clinical implications for patient care decisions such as antithrombotic use.

MRI-visible perivascular spaces in cerebral amyloid angiopathy and hypertensive arteriopathy

OBJECTIVE

To assess MRI-visible enlarged perivascular spaces (EPVS) burden and different topographical patterns (in the centrum semiovale [CSO] and basal ganglia [BG]) in 2 common microangiopathies: cerebral amyloid angiopathy (CAA) and hypertensive arteriopathy (HA).

METHODS

Consecutive patients with spontaneous intracerebral hemorrhage (ICH) from a prospective MRI cohort were included. Small vessel disease MRI markers, including cerebral microbleeds (CMBs), cortical superficial siderosis (cSS), and white matter hyperintensities (WMH), were rated. CSO-EPVS/BG-EPVS were assessed on a validated 4-point visual rating scale (0 = no EPVS, 1 = <10, 2 = 11-20, 3 = 21-40, and 4 = >40 EPVS). We tested associations of predefined high-degree (score >2) CSO-EPVS and BG-EPVS with other MRI markers in multivariable logistic regression. We subsequently evaluated associations with CSO-EPVS predominance (i.e., CSO-EPVS > BG-EPVS) and BG-EPVS predominance pattern (i.e., BG-EPVS > CSO-EPVS) in adjusted multinomial logistic regression (reference group, BG-EPVS = CSO-EPVS).

RESULTS

We included 315 patients with CAA-ICH and 137 with HA-ICH. High-degree CSO-EPVS prevalence was greater in CAA-related ICH vs HA-related ICH (43.8% vs 17.5%, p < 0.001). In multivariable logistic regression, high-degree CSO-EPVS was associated with lobar CMB (odds ratio [OR] 1.33, 95% confidence interval [CI] 1.10-1.61, p = 0.003) and cSS (OR 2.08, 95% CI 1.30-3.32, p = 0.002). Deep CMBs (OR 2.85, 95% CI 1.75-4.64, p < 0.0001) and higher WMH volume (OR 1.02, 95% CI 1.01-1.04, p = 0.010) were predictors of high-degree BG-EPVS. A CSO-EPVS-predominant pattern was more common in CAA-ICH than in HA-ICH (75.9% vs 39.4%, respectively, p < 0.0001). CSO-PVS predominance was associated with lobar CMB burden and cSS, while BG-EPVS predominance was associated with HA-ICH and WMH volumes.

CONCLUSIONS

Different patterns of MRI-visible EPVS provide insights into the dominant underlying microangiopathy type in patients with spontaneous ICH.

Abstract TMP95: Small Vessel Disease Burden and Clinical Symptoms in Cerebral Amyloid Angiopathy Patients Presenting Without Symptomatic Hemorrhage

Introduction: Cerebral amyloid angiopathy (CAA) is a common age-related small vessel disease (SVD). Patients without ICH typically present with transient focal neurological episodes (TFNEs) or cognitive symptoms. We sought to determine if SVD lesion burden differed between CAA patients first presenting with TFNEs versus cognitive symptoms.

Methods: A total of 647 patients presenting either to a stroke department (n=205) or an outpatient memory clinic (n=442), were screened for eligibility. Patients meeting modified Boston criteria for probable CAA were included and markers of SVD were quantified including cerebral microbleeds (CMBs), perivascular spaces, cortical superficial siderosis (cSS), and white matter hyperintensities (WMH). Patients were classified according to presentation symptoms (TFNEs vs cognitive). Total CAA-SVD burden was assessed using a validated summary score. Individual neuroimaging markers and total SVD burden were compared between groups using univariable and multivariable models.

Results: There were 261 probable CAA patients included. After adjustment for confounders, patients first seen for TFNEs (n=97) demonstrated a higher prevalence of cSS (p<.0001), higher WMH volumes (p=0.03) and a trend towards higher CMBs counts (p=.09). The total SVD summary score was higher in patients seen for TFNEs (adjusted OR per additional score point=1.46, 95%CI [1.16 - 1.84], p=0.013).

Conclusion: We present a large cohort of probable CAA patients without ICH and show that those first evaluated for TFNEs bear a higher burden of structural MRI SVD related damage compared to those first seen for cognitive symptoms. This study sheds light on CAA disease phenotypes, adds to the understanding of CAA clinical expression, and sets the basis for future works investigating CAA prognosis amongst phenotypes.

Abstract 212: Cortical Superficial Siderosis and Risk of Recurrent Intracerebral Haemorrhage in Cerebral Amyloid Angiopathy: A Meta-analysis

Background: Cerebral amyloid angiopathy (CAA) is a major cause of spontaneous lobar intracerebral hemorrhage (ICH) in the elderly. CAA-related ICH survivors are at substantial risk for recurrent ICH, accounting for the significant morbidity of the disease. Identifying predictors of recurrence is therefore crucial. Recent data have implicated cortical superficial siderosis (cSS) as a key hemorrhagic MRI signature of CAA, and a possible marker of increased risk for CAA-ICH recurrence. However, data remain limited. We obtained precise estimates on cSS as an independent predictor of ICH recurrence risk in CAA cohorts from a systematic review of published studies pooled with data from our centre.

Methods: We included cohort studies of consecutive CAA-related ICH patients based on the original Boston criteria, with available blood-sensitive MRI sequences at baseline for cSS assessment, and adequate follow-up for recurrent symptomatic ICH. The strength of the association between cSS and recurrent ICH was quantified using random effects models. Covariate-adjusted hazard rations (adj-HR) as provided from pre-specified Cox proportional hazard models were used for a two-stage meta-analysis.

Results: Three cohorts including 443 CAA-ICH patients were eligible for analysis. The pooled prevalence of cSS presence and disseminated cSS (>3 affected sulci) was 32% (95%CI: 32%-41%) and 21% (95%CI: 18%-25%) respectively. During a mean follow-up of 2.5 years (range: 2-3 years) 92 patients experienced recurrent ICH, a pooled risk ratio of 6.9% per year (I 2 : 63%, p=0.07). In adjusted pooled analysis, any cSS and disseminated cSS were both independently associated with increased lobar ICH recurrence risk (adj-HR: 2.4; 95%CI: 1.5-3.8; p<0.0001, I 2 : 0% and adj-HR: 4.1; 95%CI: 2.6-6.6; p<0.0001, I 2 : 47%), after adjusting for multiple strictly lobar microbleeds presence and increasing age.

Conclusions: Our findings in a large population of CAA patients with ICH and a large number of recurrence events, indicate that cSS, particularly if disseminated, is the single most important prognostic risk factor on MRI for future recurrent lobar ICH. The provided estimates may help stratify future bleeding risk in CAA, with clinical implications for prognosis and treatment.

Abstract WMP100: Topographical Distribution of Lacunes in Cerebral Amyloid Angiopathy and Deep Hypertensive Intracerebral Hemorrhage

Background/Aims: To evaluate whether the burden of lacunes located at deep and lobar brain regions, would differ between intracerebral hemorrhage patients (ICH) with cerebral amyloid angiopathy (CAA) vs patients with strictly deep cerebral microbleeds (CMB) and ICH (Deep HTN-ICH).

Methods: We defined lobar and deep lacunes similar to the topographic distribution used for ICH and microbleeds. We then compared their distribution between CAA and Deep HTN-ICH patients. The independent associations of lacune location (lobar vs deep) with diagnosis of CAA-ICH and Deep HTN-ICH were evaluated using multivariable models. The relationship between lobar and deep lacunes and WMH volume was evaluated using partial correlation analyses adjusting for age and by means of a validated visual scale.

Results: In our cohort of 316 ICH patients, lobar lacunes were more commonly present in CAA (20.4% vs 5.7% in Deep HTN-ICH, p<0.001; see figure) while deep lacunes more frequent in Deep HTN-ICH patients (15.2% vs 2.1%, p<0.001; see figure). After correction for demographics, clinical and neuroimaging markers of SVD, lobar lacunes were associated with CAA diagnosis (p=0.023), while deep lacunes with Deep HTN-ICH (p<0.001). Lobar lacunes in 80% of the cases were at least in contact with WMH and after adjustment for age they were highly correlated to WMH volume ( r=0.52, p<0.001).

Conclusions: Lobar lacunes are associated with CAA whereas deep lacunes are more frequent in patients with Strictly deep CMBs and ICH, they can thus be clinically useful in the appropriate context. Lobar lacunes seem to have a close relationship with WMH suggesting a possible common origin.

Small vessel disease burden in cerebral amyloid angiopathy without symptomatic hemorrhage

OBJECTIVE

Cerebral amyloid angiopathy (CAA) is a common age-related small vessel disease (SVD). Patients without intracerebral hemorrhage (ICH) typically present with transient focal neurologic episodes (TFNEs) or cognitive symptoms. We sought to determine if SVD lesion burden differed between patients with CAA first presenting with TFNEs vs cognitive symptoms.

METHODS

A total of 647 patients presenting either to a stroke department (n = 205) or an outpatient memory clinic (n = 442) were screened for eligibility. Patients meeting modified Boston criteria for probable CAA were included and markers of SVD were quantified, including cerebral microbleeds (CMBs), perivascular spaces, cortical superficial siderosis (cSS), and white matter hyperintensities (WMHs). Patients were classified according to presentation symptoms (TFNEs vs cognitive). Total CAA-SVD burden was assessed using a validated summary score. Individual neuroimaging markers and total SVD burden were compared between groups using univariable and multivariable models.

RESULTS

There were 261 patients with probable CAA included. After adjustment for confounders, patients first seen for TFNEs (n = 97) demonstrated a higher prevalence of cSS (p < 0.0001), higher WMH volumes (p = 0.03), and a trend toward higher CMB counts (p = 0.09). The total SVD summary score was higher in patients seen for TFNEs (adjusted odds ratio per additional score point 1.46, 95% confidence interval 1.16-1.84, p = 0.013).

CONCLUSIONS

Patients with probable CAA without ICH first evaluated for TFNEs bear a higher burden of structural MRI SVD-related damage compared to those first seen for cognitive symptoms. This study sheds light on neuroimaging profile differences across clinical phenotypes of patients with CAA without ICH.

Noncontrast Computed Tomography Hypodensities Predict Poor Outcome in Intracerebral Hemorrhage Patients

BACKGROUND AND PURPOSE

Noncontrast computed tomographic (CT) hypodensities have been shown to be associated with hematoma expansion in intracerebral hemorrhage (ICH), but their impact on functional outcome is yet to be determined. We evaluated whether baseline noncontrast CT hypodensities are associated with poor clinical outcome.

METHODS

We performed a retrospective review of a prospectively collected cohort of consecutive patients with primary ICH presenting to a single academic medical center between 1994 and 2016. The presence of CT hypodensities was assessed by 2 independent raters on the baseline CT. Unfavorable outcome was defined as a modified Rankin score >3 at 90 days. The associations between CT hypodensities and unfavorable outcome were investigated using uni- and multivariable logistic regression models.

RESULTS

During the study period, 1342 patients presented with ICH and 800 met restrictive inclusion criteria (baseline CT available for review, and 90-day outcome available). Three hundred and four (38%) patients showed hypodensities on CT, and 520 (65%) patients experienced unfavorable outcome. In univariate analysis, patients with unfavorable outcome were more likely to demonstrate hypodensities (48% versus 20%; P<0.0001). After adjustment for age, admission Glasgow coma scale, warfarin use, intraventricular hemorrhage, baseline ICH volume, and location, CT hypodensities were found to be independently associated with an increase in the odds of unfavorable outcome (odds ratio 1.70, 95% confidence interval [1.10-2.65]; P=0.018).

CONCLUSIONS

The presence of noncontract CT hypodensities at baseline independently predicts poor outcome and comes as a useful and widely available addition to our ability to predict ICH patients' clinical evolution.

Recurrent hemorrhage risk and mortality in hereditary and sporadic cerebral amyloid angiopathy

OBJECTIVE

To determine whether hereditary cerebral hemorrhage with amyloidosis-Dutch type (HCHWA-D), a monogenetic disease model for the sporadic variant of amyloid angiopathy (sCAA), has a comparable recurrent intracerebral hemorrhage (ICH) risk and mortality after a first symptomatic ICH.

METHODS

We included patients with HCHWA-D from the Leiden University Medical Center and patients with sCAA from the Massachusetts General Hospital in a cohort study. Baseline characteristics, hemorrhage recurrence, and short- and long-term mortality were compared. Hazard ratios (HRs) adjusted for age and sex were calculated with Cox regression analyses.

RESULTS

We included 58 patients with HCHWA-D and 316 patients with sCAA. Patients with HCHWA-D had fewer cardiovascular risk factors (≥1 risk factor 24% vs 70% in sCAA) and were younger at the time of presenting hemorrhage (mean age 54 vs 72 years in sCAA). Eight patients (14%) with HCHWA-D and 46 patients (15%) with sCAA died before 90 days. During a mean follow-up time of 5 ± 4 years (total 1,550 person-years), the incidence rate of recurrent ICH in patients with HCHWA-D was 20.9 vs 8.9 per 100 person-years in sCAA. Patients with HCHWA-D had a long-term mortality of 8.2 vs 8.4 per 100 person-years in patients with sCAA. After adjustments, patients with HCHWA-D had a higher risk of recurrent ICH (HR 2.8; 95% confidence interval 1.6-4.9; p < 0.001) and a higher long-term mortality (HR 2.8; 95% confidence interval 1.5-5.2; p = 0.001).

CONCLUSIONS

Patients with HCHWA-D have worse long-term prognosis after a first ICH than patients with sCAA. The absence of cardiovascular risk factors in most patients with HCHWA-D suggests that vascular amyloid is responsible for the recurrent hemorrhages. HCHWA-D is therefore a pure form of cerebral amyloid angiopathy with an accelerated clinical course and provides a good model to study the pathophysiology and future therapeutic interventions of amyloid-related hemorrhages.

Intracranial atherosclerosis and cerebral small vessel disease in intracerebral hemorrhage patients

BACKGROUND

The association between cerebral small vessel diseases (cSVD) and intracranial atherosclerosis is debated and conflicting results have been reported. We sought to investigate this association in patients with intracerebral hemorrhage (ICH), due to severe cSVD.

METHODS

Consecutive ICH patients were divided into those meeting criteria for cerebral amyloid angiopathy (CAA) and those with deep hypertensive ICH consistent with hypertensive cSVD (HTN-SVD). White matter hyperintensity volumes (WMH) and microbleed counts (MB) were measured on MRI. CTA was rated for severity of intracranial carotid calcifications and for presence of >50% intracranial stenosis (ICS). Associations of intracranial atherosclerosis severity with type of SVD (CAA vs HTN-cSVD) and with imaging and clinical markers of cSVD burden were analyzed.

RESULTS

The cohort included 253 CAA and 90 HTN-SVD patients. In multivariable models, the type of cSVD (CAA vs. HTN-cSVD) was not associated with calcification severity (OR=1.04, 95% CI [0.62-3.5], p=0.37) or presence of ICS (OR=0.84, 95% CI [0.21-2.74], p=0.78). We found no association between intracranial atherosclerosis (calcifications and stenoses) and parenchymal markers of cSVD severity (WMH and MB, adjusted p≥0.2 for all comparisons) and no association with presence of dementia before ICH (adjusted p≥0.2 for both comparisons).

CONCLUSIONS

We found no association between intracranial atherosclerosis and parenchymal or clinical consequences of cSVD, suggesting that cSVDs while sharing some risk factors are not influenced by upstream larger vessel pathologies.

Cortical atrophy in patients with cerebral amyloid angiopathy: a case-control study

BACKGROUND

Loss of cortical grey matter is a diagnostic marker of many neurodegenerative diseases, and is a key mediator of cognitive impairment. We postulated that cerebral amyloid angiopathy (CAA), characterised by cortical vascular amyloid deposits, is associated with cortical tissue loss independent of parenchymal Alzheimer's disease pathology. We tested this hypothesis in patients with hereditary cerebral haemorrhage with amyloidosis-Dutch type (HCHWA-D), a monogenetic disease with minimal or no concomitant Alzheimer's disease pathology, as well as in patients with sporadic CAA and healthy and Alzheimer's disease controls.

METHODS

In this observational case-control study, we included six groups of participants: patients diagnosed with HCHWA-D using genetic testing; healthy controls age-matched to the HCHWA-D group; patients with probable sporadic CAA without dementia; two independent cohorts of healthy controls age-matched to the CAA group; and patients with Alzheimer's disease age-matched to the CAA group. De-identified (but unmasked) demographic, clinical, radiological, and genetic data were collected at Massachusetts General Hospital (Boston, MA, USA), at Leiden University (Leiden, Netherlands), and at sites contributing to Alzheimer's Disease Neuroimaging Initiative (ADNI). The primary outcome measure was cortical thickness. The correlations between cortical thickness and structural lesions, and blood-oxygen-level-dependent time-to-peak (BOLD-TTP; a physiological measure of vascular dysfunction) were analysed to understand the potential mechanistic link between vascular amyloid and cortical thickness. The radiological variables of interest were quantified using previously validated computer-assisted tools, and all results were visually reviewed to ensure their accuracy.

RESULTS

Between March 15, 2006, and Dec 1, 2014, we recruited 369 individuals (26 patients with HCHWA-D and 28 age-matched, healthy controls; 63 patients with sporadic CAA without dementia; two healthy control cohorts with 63 and 126 individuals; and 63 patients with Alzheimer's disease). The 26 patients with HCHWA-D had thinner cortices (2·31 mm [SD 0·18]) than the 28 healthy controls (mean difference -0·112 mm, 95% CI -0·190 to -0·034, p=0·006). The 63 patients with sporadic CAA without dementia had thinner cortices (2·17 mm [SD 0·11]) than the two healthy control cohorts (n=63, mean difference -0·14 mm, 95% CI -0·17 to -0·10, p<0·0001; and n=126, -0·10, -0·13 to -0·06, p<0·0001). All differences remained independent in multivariable analyses. The 63 patients with Alzheimer's disease displayed more severe atrophy than the patients with sporadic CAA (2·1 mm [SD 0·14], difference 0·07 mm, 95% CI 0·11 to 0·02, p=0·005). We found strong associations between cortical thickness and vascular dysfunction in the patients with HCHWA-D (ρ=-0·58, p=0·003) or sporadic CAA (r=-0·4, p=0·015), but not in controls. Vascular dysfunction was identified as a mediator of the effect of hereditary CAA on cortical atrophy, accounting for 63% of the total effect.

INTERPRETATION

The appearance of cortical thinning in patients with HCHWA-D indicates that vascular amyloid is an independent contributor to cortical atrophy. These results were reproduced in patients with the more common sporadic CAA. Our findings also suggest that CAA-related cortical atrophy is at least partly mediated by vascular dysfunction. Our results also support the view that small vessel diseases such as CAA can cause cortical atrophy even in the absence of Alzheimer's disease, a conclusion that can help radiologists, neurologists, and other clinicians who diagnose these common geriatric conditions.

FUNDING

National Institutes of Health.

Abstract TP458: Is There “Crosstalk” Between Intracranial Arterial Pathologies and Small Vessel Disease??

Background: Interactions between intracranial arterial pathologies (IAP) and cerebral small vessel disease (SVD) are an increasingly debated topic.

Hypothesis: We analyzed associations between the type/severity of SVD and two IAPs, the intracranial arterial calcifications (ICAC) and intracranial stenosis (ICS) in intracerebral hemorrhage (ICH) patients.

Methods: Consecutive ICH patients from a prospective cohort were included. Patients were divided into those meeting Boston criteria for cerebral amyloid angiopathy (CAA) and those with strictly deep hypertensive ICH consistent with hypertensive SVD (HTN-SVD). White matter hyperintensity volume (WMH) and microbleed count (MB) were quantitatively measured on MRI as markers of SVD severity. Head CT angiography was rated for presence of ICAC and for presence of >50% intracranial arterial stenosis (ICS). Associations of IAPs with the type of SVD (CAA vs HTN) as well as imaging markers of SVD severity were analyzed in multivariate models. We also explored the association between IAPs and presence of pre-ICH dementia.

Results: The cohort included 253 CAA patients and 90 HTN-SVD. CAA patients were older (73.5 vs 64.8, p<0.001), demonstrating higher WMH (25ml vs 16ml, p<0.001) but lower prevalence of hypertension than HTN-ICH. In univariate comparisons between CAA and HTN-SVD, the presence of ICACs (74% vs 72%, p=0.7) and ICS (7% vs 7.8%, p=0.8) were not different. ICS was not related to the type of SVD in multivariate models either. Using multivariate logistic regression, HTN-SVD was independently associated with presence of ICAC (adjusted OR = 2.56 [95% CI 1.1-6.2, p=0.002), as well as older age, male gender and hypercholesterolemia. We found no association between IAPs and parenchymal markers of SVD severity (WMH and MB) (all p>0.2) and no association with presence of dementia before ICH (p>0.2).

Conclusions: HTN-SVD is associated with increased ICAC in multivariate models, suggesting either shared risk factors or direct interactions between SVD and IAP. There is no association of intracranial large artery pathologies (ICAC, ICS) with parenchymal (WMH, MB) or clinical (dementia) consequences of cerebral small vessel diseases.

Abstract WMP90: Florbetapir PET to Diagnose Cerebral Amyloid Angiopathy

Introduction: Previous studies showed that Pittsburgh Compound B (PiB) labels vascular amyloid characteristic of cerebral amyloid angiopathy (CAA) on PET scans; PiB is not approved for clinical use, however.

Hypothesis: We hypothesized that Florbetapir, an FDA-approved PET tracer, can detect amyloid in CAA and help distinguish CAA-related intracerebral hemorrhage (ICH) from hypertensive ICH (HTN-ICH).

Methods: We prospectively enrolled non-demented survivors of primary ICH related to probable CAA (per Boston Criteria, n=10) and HTN-ICH (n=9). All patients underwent Florbetapir-PET, multimodal MRI, and additional PiB-PET for the CAA patients. Amyloid burden was assessed quantitatively using parametric maps and also visually, classified as positive or negative. Spatial correlations between Florbetapir and PiB retention were used to test vascular amyloid binding in CAA. We have tested the diagnostic value of Florbetapir by comparing global and occipital mean Florbetapir retention (standard uptake value ratio, SUVR) as well as Florbetapir positive/negative status between CAA and HTN-ICH groups.

Results: The CAA and HTN-ICH groups had similar age (66.9 vs 67.1), sex and white matter hyperintensity volumes (31ml vs 30ml, all p>0.8). Florbetapir uptake and PiB retention strongly correlated in CAA patients both globally within cerebral cortex (r=0.96, p<0.001) and regionally in occipital, frontal, temporal, parietal cortices (all r>0.8, all p < 0.01). Mean global cortical Florbetapir uptake was significantly higher in CAA than HTN-ICH (SUVR: 1.41±0.16 vs 1.16±0.08, p=0.001) as was mean occipital SUVR (1.44±0.12 vs 1.17±0.08, p<0.001), remaining independent after correcting for global SUVR (p=0.02). Visual rating for Florbetapir positive/negative demonstrated perfect interrater agreement (k=1) between two trained neurologists blinded to all other information and was positive for all 10 CAA patients vs 1 of 9 HTN-ICH patients (sensitivity 100%, specificity 89%).

Conclusions: Florbetapir, like PiB, appears to label vascular amyloid in patients with CAA-related ICH. Data using the approved Florbetapir binary visual reading method suggest sufficient sensitivity and specificity for diagnostic use in appropriate clinical settings.

White matter hyperintensity patterns in cerebral amyloid angiopathy and hypertensive arteriopathy

OBJECTIVE

To identify different white matter hyperintensity (WMH) patterns between 2 hemorrhage-prone cerebral small vessel diseases (SVD): cerebral amyloid angiopathy (CAA) and hypertensive arteriopathy (HA).

METHODS

Consecutive patients with SVD-related intracerebral hemorrhage (ICH) from a single-center prospective cohort were analyzed. Four predefined subcortical WMH patterns were compared between the CAA and HA groups. These WMH patterns were (1) multiple subcortical spots; (2) peri-basal ganglia (BG); (3) large posterior subcortical patches; and (4) anterior subcortical patches. Their associations with other imaging (cerebral microbleeds [CMBs], enlarged perivascular spaces [EPVS]) and clinical markers of SVD were investigated using multivariable logistic regression.

RESULTS

The cohort included 319 patients with CAA and 137 patients with HA. Multiple subcortical spots prevalence was higher in the CAA compared to the HA group (29.8% vs 16.8%; p = 0.004). Peri-BG WMH pattern was more common in the HA- vs the CAA-ICH group (19% vs 7.8%; p = 0.001). In multivariable logistic regression, presence of multiple subcortical spots was associated with lobar CMBs (odds ratio [OR] 1.23; 95% confidence interval [CI] 1.01-1.50, p = 0.039) and high degree of centrum semiovale EPVS (OR 2.43; 95% CI 1.56-3.80, p < 0.0001). By contrast, age (OR 1.05; 95% CI 1.02-1.09, p = 0.002), deep CMBs (OR 2.46; 95% CI 1.44-4.20, p = 0.001), total WMH volume (OR 1.02; 95% CI 1.01-1.04, p = 0.002), and high BG EPVS degree (OR 8.81; 95% CI 3.37-23.02, p < 0.0001) were predictors of peri-BG WMH pattern.

CONCLUSION

Different patterns of subcortical leukoaraiosis visually identified on MRI might provide insights into the dominant underlying microangiopathy type as well as mechanisms of tissue injury in patients with ICH.

The characteristics of superficial siderosis and convexity subarachnoid hemorrhage and clinical relevance in suspected cerebral amyloid angiopathy

BACKGROUND AND AIMS

Systematic studies of superficial siderosis (SS) and convexity subarachnoid hemorrhage (cSAH) in patients with suspected cerebral amyloid angiopathy (CAA) without lobar intracerebral hemorrhage (ICH) are lacking. We sought to determine the potential anatomic correlation between SS/cSAH and transient focal neurological episodes (TFNE) and whether SS/cSAH is predictor of future cerebral hemorrhagic events in these patients.

METHODS

We enrolled 90 consecutive patients with suspected CAA (due to the presence of strictly lobar microbleeds (CMBs) and/or SS/cSAH) but without the history of symptomatic lobar ICH who underwent brain MRI including T2*-weighted, diffusion-weighted imaging and fluid-attenuated inversion recovery sequences from an ongoing single center CAA cohort from 1998 to 2012. Evaluation of SS, cSAH and CMBs was performed. Medical records and follow-up information were obtained from prospective databases and medical charts. TFNE was defined according to published criteria and electroencephalogram reports were reviewed.

RESULTS

Forty-one patients (46%) presented with SS and/or cSAH. The prevalence of TFNE was significantly higher in those with SS/cSAH (61 vs. 10%; p < 0.001) and anatomically correlated with the location of cSAH, but not SS. The majority of TFNE in patients with SS/cSAH presented with spreading sensory symptoms. Intermittent focal slowing on electroencephalogram was present in the same area as SS/cSAH in 6 patients, but no epileptiform activity was found in any patients. Among those with available clinical follow-up (76/90 patients, 84%), ten patients with SS/cSAH (29%, median time from the scan for all patients with SS/cSAH: 21 months) had a symptomatic cerebral bleeding event on follow up (average time to events: 34 months) compared with only 1 event (2.4%, 25 months from the scan) in patients without SS/​cSAH (time to event: 25 months) (p = 0.001). The location of hemorrhages on follow-up scan was not in the same location of previously noted SS/cSAH in 9 of 10 patients. Follow-up imaging was obtained in 9 of 17 patients with cSAH and showed evidence of SS in the same location as initial cSAH in all these 9 cases.

CONCLUSIONS

SS/cSAH is common in patients with suspected CAA without lobar intracerebral hemorrhage and may have a significantly higher risk of future cerebral bleeding events, regardless of the severity of the baseline CMB burden. The findings further highlight a precise anatomical correlation between TFNE and cSAH, but not SS. Distinct from transient ischemic attack or seizure, the majority of TFNE caused by SS/cSAH appear to present with spreading sensory symptoms.

Incidence of symptomatic hemorrhage in patients with lobar microbleeds

BACKGROUND AND PURPOSE

Lobar microbleeds suggestive of cerebral amyloid angiopathy (CAA) are often identified on MRI in the absence of lobar intracerebral hemorrhage (ICH). We compared the baseline characteristics and risk of subsequent ICH among such patients to those presenting with CAA-related lobar ICH.

METHODS

Clinical data (demographics, risk factors), apolipoprotein E genotype, neuroimaging markers of CAA severity (microbleed counts, leukoaraiosis volume), and clinical outcomes (incidence rates of ICH and death during a mean follow-up of 5.3±3.8 years) were compared between 63 patients enrolled because of incidentally found microbleeds and 316 with CAA-related ICH, in our prospectively enrolled cohort. Predictors of incident ICH were explored in the microbleed-only patients using multivariable Cox regression models.

RESULTS

Microbleed-only patients shared similar demographic, apolipoprotein E, and vascular risk profiles with lobar ICH patients, but had more lobar microbleeds (median, 10 versus 2; P<0.001) and higher leukoaraiosis volumes (median, 31 versus 23 mL; P=0.02). Microbleed-only patients had a nontrivial incidence rate of ICH, not different from patients presenting with ICH (5 versus 8.9 per 100 person-years; adjusted hazard ratio, 0.58; 95% confidence interval, 0.31-1.06; P=0.08). Microbleed-only patients had a higher mortality rate (hazard ratio, 1.67; 95% confidence interval, 1.1-2.6) compared with ICH survivors. Warfarin use and increasing age were independent predictors of future ICH among microbleed-only patients after correction for other covariates.

CONCLUSIONS

Patients presenting with isolated lobar microbleeds on MRI have a genetic, neuroimaging, and hemorrhagic risk profile suggestive of severe CAA pathology. They have a substantial risk of incident ICH, potentially affecting decisions regarding anticoagulation in clinical situations.

Abstract W P250: The Impact of Acute Hypertensive Response on Mortality After Intracerebral Hemorrhage Differs Among Patients With and Without Left Ventricle Hypertrophy

Background: While acute hypertensive response (AHR) predicts worse outcome in intracerebral hemorrhage (ICH), the INTERACT-2 trial recently failed to definitively demonstrate a major benefit of intensive blood pressure reduction on these patients. A possible explanation is that the detrimental effect of AHR on outcome may differ among ICH patients with and without previous chronic hypertension.

Objective: to explore whether the prognosis of patients with AHR during the acute phase of ICH differs according to the presence or absence of left ventricle hypertrophy (LVH), which is a marker of chronic hypertensive organ damage.

Method: we performed a retrospective analysis of a prospective cohort of patients with primary ICH presenting to an academic hospital between January/2000 and December/2012 with age > 18 years, who had a transthoracic echocardiogram available. LVH was defined according to Penn convention. AHR was defined as systolic blood pressure > 180 mmHg on admission. Mantel-Haenszel test was initially used to assess if LVH status influenced the effect of AHR on mortality. For subsequent analyses, ICH patients were divided in 3 groups: without AHR (reference); AHR without LVH; AHR with LVH. A multivariate logistic regression model was then used to identify independent predictors of mortality at 30-days.

Results: 430 patients met inclusion criteria. AHR was present in 196 (46.6%), LVH was present in 233 (54.2%); 30-day mortality was 15.6%. On Mantel-Haenszel test, we found a trend (p=0.09) suggesting that absence of LVH increased AHR effect on mortality (OR:1.64; 95% CI: 0.95-2.8; p=0.07). On multivariate analysis, patients with AHR without LVH had significantly higher mortality (OR: 2.65; 95%CI: 1.15 to 6.1; p=0.022) when compared to patients without AHR, after adjusting for baseline characteristics. There was only a trend towards increased mortality in the group of patients with AHR and LVH (OR:2.22; 95% CI: 0.99-5.0; p=0.053).

Conclusions: Patients without chronic hypertension appear to be more susceptible to the detrimental effects of AHR during the acute phase of ICH. Stratification of patients with ICH may help to identify those that will have greater benefit with intensive blood pressure reduction in the acute phase of ICH.

Abstract TP295: Different Patterns of Subcortical White Matter Disease in Patients with Cerebral Amyloid Angiopathy and Hypertensive Intracerebral Hemorrhage

Objective: We aimed to identify the potential contributions of cerebral amyloid angiopathy (CAA) and hypertensive microvasculopathy on periventricular (PV) and subcortical (SC) white matter disease (WMD).

Methods: Total, SC and PV WMD volumes of 359 CAA patients and 102 patients with hypertensive intracerebral hemorrhage (htn-ICH) were quantitatively measured on FLAIR MRI. The presence of 6 different subcortical WMD patterns (detailed under Results and Figure 1) was recorded. The independent predictors of each of these WMD variables were explored using multivariate models that included the diagnosis (CAA vs htn-ICH), age, gender, ApoE genotype, vascular risk factors, total WMD volume as well as lobar and deep microbleed (MB) counts from T2*MRI.

Results: CAA patients were older (mean 74 vs 68, p<0.001) with a higher WMD burden (p<0.05 for total, PV and SC WMD) than htn-ICH cases. Older age, higher lobar and deep MB counts were independent predictors of both total and PV WMH (p<0.01 for all predictors) whereas only high lobar MB count was independently associated with SC WMD (p<0.001). CAA-related covariates (CAA diagnosis and/or lobar MB counts) were independently associated with large posterior SC WMD (Fig 1a, frequency 16% in CAA vs 5% in htn-ICH, p<0.001) and anterior SC WMD (Fig 1b, 46% vs 24%, p<0.01). Peri-basal ganglia WMD (Fig 1c) pattern was more frequent in htn-ICH (29% vs 10%, p<0.001) and independently associated with deep MB count. The SC spots (Fig 1d, p=0.16), U-shaped SC WMD pattern (Fig 1e, p=0.17) and severe-coalescent WMD (Fig 1f, p=0.5) were not independently related to CAA or htn-ICH.

Conclusions: Our results show that CAA pathology is associated with the severity of both PV and SC WMD as well as presence of severe posterior and anterior SC disease. A pattern of deep peri-basal ganglia WMD is mostly associated with hypertensive disease. Recognition of these patterns might help understand the dominant type of microvasculopathy in older individuals with WMD.

Characteristic distributions of intracerebral hemorrhage-associated diffusion-weighted lesions

OBJECTIVES

To determine whether small diffusion-weighted imaging (DWI) lesions occur beyond the acute posthemorrhage time window in patients with intracerebral hemorrhage (ICH) and to characterize their spatial distribution in patients with lobar and deep cerebral hemorrhages.

METHODS

In this cross-sectional study, we retrospectively analyzed 458 MRI scans obtained in the acute (≤ 7 days after ICH) or nonacute (>14 days after ICH) phases from 392 subjects with strictly lobar (n = 276) and deep (n = 116) ICH (48.7% women; mean age 72.8 ± 11.7 years). DWI, apparent diffusion coefficient maps, fluid-attenuated inversion recovery, and T2* MRIs were reviewed for the presence and location of DWI lesions.

RESULTS

We identified 103 DWI hyperintense lesions on scans from 62 subjects, located mostly in lobar brain regions (90 of 103, 87.4%). The lesions were not uniformly distributed throughout the brain lobes; patients with strictly lobar ICH had relative overrepresentation of lesions in frontal lobe, and patients with deep ICH in parietal lobe (p = 0.002). Although the frequency of DWI lesions tended to be greater on scans performed within 7 days after ICH (39 of 214, 18.2%), they continued at high frequency in the nonacute period as well (23 of 178, 12.9%, odds ratio 1.5, 95% confidence interval 0.86-2.6 for acute vs nonacute). There was also no difference in frequency of lesions on acute and nonacute scans among 66 subjects with MRIs in both time periods (8 of 66 acute, 10 of 66 nonacute, odds ratio 0.77, 95% confidence interval 0.25-2.4).

CONCLUSIONS

The high frequency of DWI lesions beyond the acute post-ICH period and their characteristic distributions suggest that they are products of the small vessel diseases that underlie ICH.

White matter alterations in cerebral amyloid angiopathy measured by diffusion tensor imaging

BACKGROUND AND PURPOSE

Cerebral amyloid angiopathy (CAA) represents beta-amyloid deposition in the small- and medium-sized vessels of the brain and meninges. CAA contributes to altered vessel function and is associated with white matter damage, cognitive impairment, and most salient, hemorrhagic stroke. We used diffusion tensor imaging to evaluate the anatomic distribution of white matter degeneration in participants diagnosed with advanced CAA.

METHODS

Diffusion tensor imaging was obtained from 11 participants diagnosed with CAA-related intracerebral hemorrhage and 13 matched healthy control participants. Fractional anisotropy (FA) and diffusivity maps were compared using voxel based t test and region-of-interest analyses.

RESULTS

FA was reduced in CAA in temporal white matter and in the splenium of the corpus callosum (P<0.001 with approximately 17% reduction in temporal white matter and 15% reduction in the splenium). FA was marginally increased in CAA in the posterior limb of the internal capsule and subthalamic gray matter regions (approximately 7% increase in subthalamic gray). FA changes were bilateral, remained significant in cluster analysis controlling for multiple comparisons, and did not depend on the hemisphere of the cerebral hemorrhage. Diffusivity was not substantially altered.

CONCLUSIONS

These findings suggest that a pattern of regional brain tissue degeneration is a characteristic feature of advanced CAA.