Probable Cerebral Amyloid Angiopathy Research Articles

Boston Criteria v2.0 for Cerebral Amyloid Angiopathy Without Hemorrhage: An MRI-Neuropathologic Validation Study.

Updated criteria for the clinical-MRI diagnosis of cerebral amyloid angiopathy (CAA) have recently been proposed. However, their performance in individuals without symptomatic intracerebral hemorrhage (ICH) presentations is less defined. We aimed to assess the diagnostic performance of the Boston criteria version 2.0 for CAA diagnosis in a cohort of individuals ranging from cognitively normal to dementia in the community and memory clinic settings. Fifty-four participants from the Mayo Clinic Study of Aging or Alzheimer's Disease Research Center were included if they had an antemortem MRI with gradient-recall echo sequences and a brain autopsy with CAA evaluation. Performance of the Boston criteria v2.0 was compared with v1.5 using histopathologically verified CAA as the reference standard. The median age at MRI was 75 years (interquartile range 65-80) with 28/54 participants having histopathologically verified CAA (i.e., moderate-to-severe CAA in at least 1 lobar region). The sensitivity and specificity of the Boston criteria v2.0 were 28.6% (95% CI 13.2%-48.7%) and 65.3% (95% CI 44.3%-82.8%) for probable CAA diagnosis (area under the receiver operating characteristic curve [AUC] 0.47) and 75.0% (55.1-89.3) and 38.5% (20.2-59.4) for any CAA diagnosis (possible + probable; AUC 0.57), respectively. The v2.0 Boston criteria were not superior in performance compared with the prior v1.5 criteria for either CAA diagnostic category. The Boston criteria v2.0 have low accuracy in patients who are asymptomatic or only have cognitive symptoms. Additional biomarkers need to be explored to optimize CAA diagnosis in this population.

Superficial small cerebellar infarcts in cerebral amyloid angiopathy on 3 T MRI: A preliminary study

BackgroundStrictly superficial cerebellar microbleeds and cerebellar superficial siderosis have been considered markers of advanced cerebral amyloid angiopathy (CAA), but there are few studies on cerebellar ischemic lesions in CAA. We investigated the presence of superficial small cerebellar infarct (SCI) ≤15 mm and its relation to magnetic resonance imaging (MRI) markers in patients with probable CAA. MethodsEighty patients with probable CAA were retrospectively evaluated. The presence of superficial SCIs was examined, along with cerebellar microbleeds and cerebellar superficial siderosis, using 3-T MRI. Lobar cerebral microbleeds, cortical superficial siderosis (cSS), enlargement of the perivascular space in the centrum semiovale, and white matter hyperintensity were assessed and the total CAA-small vessel disease (SVD) score was calculated. ResultsNine of the 80 patients (11.3%) had a total of 16 superficial SCIs. By tentatively defining SCI <4 mm as cerebellar microinfarcts, 8 out of 16 (50%) superficial SCIs corresponded to cerebellar microinfarcts. The total CAA-SVD score was significantly higher in patients with superficial SCIs (p = 0.01). The prevalence of cSS (p = 0.018), cortical cerebral microinfarct (p = 0.034), and superficial cerebellar microbleeds (p = 0.006) was significantly higher in patients with superficial SCIs. The number of superficial cerebellar microbleeds was also significantly higher in patients with superficial SCIs (p = 0.001). ConclusionsOur results suggest that in patients with CAA, superficial SCIs (including microinfarcts) on MRI may indicate more severe, advanced-stage CAA. These preliminary findings should be verified by larger prospective studies in the future.

Sensitivity of the Boston criteria version 2.0 in Dutch-type hereditary cerebral amyloid angiopathy.

The revised Boston criteria v2.0 for cerebral amyloid angiopathy (CAA) add two radiological markers to the existing criteria: severe visible perivascular spaces in the centrum semiovale and white matter hyperintensities (WMHs) in a multispot pattern. This study aims to determine the sensitivity of the updated criteria in mutation carriers with Dutch-type hereditary CAA (D-CAA) in an early and later disease stage. In this cross-sectional study, we included presymptomatic and symptomatic D-CAA mutation carriers from our prospective natural history study (AURORA) at the Leiden University Medical Center between 2018 and 2021. 3-Tesla scans were assessed for CAA-related magnetic resonance imaging (MRI) markers. We compared the sensitivity of the Boston criteria v2.0 to the previously used modified Boston criteria v1.5. We included 64 D-CAA mutation carriers (mean age 49 years, 55% women, 55% presymptomatic). At least one white matter (WM) feature was seen in 55/64 mutation carriers (86%: 74% presymptomatic, 100% symptomatic). Fifteen (23%) mutation carriers, all presymptomatic, showed only WM features and no hemorrhagic markers. The sensitivity for probable CAA was similar between the new and the previous criteria: 11/35 (31%) in presymptomatic mutation carriers and 29/29 (100%) in symptomatic mutation carriers. The sensitivity for possible CAA in presymptomatic mutation carriers increased from 0/35 (0%) to 15/35 (43%) with the new criteria. The Boston criteria v2.0 increase the sensitivity for detecting possible CAA in presymptomatic D-CAA mutation carriers and, therefore, improve the detection of the early phase of CAA.

Cerebral tau pathology in cerebral amyloid angiopathy.

Tau, a hallmark of Alzheimer's disease, is poorly characterized in cerebral amyloid angiopathy. We aimed to assess the clinico-radiological correlations between tau positron emission tomography scans and cerebral amyloid angiopathy. We assessed cerebral amyloid and hyperphosphorylated tau in patients with probable cerebral amyloid angiopathy (n = 31) and hypertensive small vessel disease (n = 27) using 11C-Pittsburgh compound B and 18F-T807 positron emission tomography. Multivariable regression models were employed to assess radio-clinical features related to cerebral tau pathology in cerebral amyloid angiopathy. Cerebral amyloid angiopathy exhibited a higher cerebral tau burden in the inferior temporal lobe [1.25 (1.17-1.42) versus 1.08 (1.05-1.22), P < 0.001] and all Braak stage regions of interest (P < 0.05) than hypertensive small vessel disease, although the differences were attenuated after age adjustment. Cerebral tau pathology was significantly associated with cerebral amyloid angiopathy-related vascular markers, including cortical superficial siderosis (β = 0.12, 95% confidence interval 0.04-0.21) and cerebral amyloid angiopathy score (β = 0.12, 95% confidence interval 0.03-0.21) after adjustment for age, ApoE4 status and whole cortex amyloid load. Tau pathology correlated significantly with cognitive score (Spearman's ρ=-0.56, P = 0.001) and hippocampal volume (-0.49, P = 0.007), even after adjustment. In conclusion, tau pathology is more frequent in sporadic cerebral amyloid angiopathy than in hypertensive small vessel disease. Cerebral amyloid angiopathy-related vascular pathologies, especially cortical superficial siderosis, are potential markers of cerebral tau pathology suggestive of concomitant Alzheimer's disease.

Profiling amyloid-β peptides as biomarkers for cerebral amyloid angiopathy.

Brain amyloid-β (Aβ) deposits are key pathological hallmarks of both cerebral amyloid angiopathy (CAA) and Alzheimer's disease (AD). Microvascular deposits in CAA mainly consist of the Aβ40 peptide, whereas Aβ42 is the predominant variant in parenchymal plaques in AD. The relevance in pathogenesis and diagnostic accuracy of various other Aβ isoforms in CAA remain understudied. We aimed to investigate the biomarker potential of various Aβ isoforms in cerebrospinal fluid (CSF) to differentiate CAA from AD pathology. We included 25 patients with probable CAA, 50 subjects with a CSF profile indicative of AD pathology (AD-like), and 23 age- and sex-matched controls. CSF levels of Aβ1-34 , Aβ1-37 , Aβ1-38 , Aβ1-39 , Aβ1-40 , and Aβ1-42 were quantified by liquid chromatography mass spectrometry. Lower CSF levels of all six Aβ peptides were observed in CAA patients compared with controls (p = 0.0005-0.03). Except for Aβ1-42 (p = 1.0), all peptides were decreased in CAA compared with AD-like subjects (p = 0.007-0.03). Besides Aβ1-42 , none of the Aβ peptides were decreased in AD-like subjects compared with controls. All Aβ peptides combined differentiated CAA from AD-like subjects better (area under the curve [AUC] 0.84) than individual peptide levels (AUC 0.51-0.75). Without Aβ1-42 in the model (since decreased Aβ1-42 served as AD-like selection criterion), the AUC was 0.78 for distinguishing CAA from AD-like subjects. CAA patients and AD-like subjects showed distinct disease-specific CSF Aβ profiles. Peptides shorter than Aβ1-42 were decreased in CAA patients, but not AD-like subjects, which could suggest different pathological mechanisms between vascular and parenchymal Aβ accumulation. This study supports the potential use of this panel of CSF Aβ peptides to indicate presence of CAA pathology with high accuracy.

Minocycline in Severe Cerebral Amyloid Angiopathy: A Single-Center Cohort Study.

Evidence from animal studies suggests that minocycline may reduce lobar intracerebral hemorrhage (ICH) recurrence in cerebral amyloid angiopathy, possibly by inhibiting perivascular extracellular matrix degradation in cerebral small vessels. There is currently no evidence of its safety or efficacy in humans with cerebral amyloid angiopathy. To provide preliminary data to support future studies of minocycline's efficacy, the authors performed a retrospective single-center cohort study to assess the incidence of recurrent ICH in patients with an aggressive clinical course of probable cerebral amyloid angiopathy who had been prescribed minocycline off-label via shared decision-making. Crude incidence rate ratios were calculated to compare incidence rates before versus after treatment. Sixteen patients (mean age at minocycline initiation, 66.3±3.5 years; women 62.5%; median of 3 lobar ICHs [range, 1-6]) were initiated on minocycline and followed for a median of 12.4 months (range, 1.8-61.4 months). Adverse events were reported in 4 of 16 patients (gastroenteric, n=3; dizziness, n=1) and were considered mild. ICH incidence sharply increased the year before minocycline initiation compared with the preceding years (2.18 [95% CI, 1.50-3.07] versus 0.40 [95% CI, 0.25-0.60] events per patient-year) and fell to 0.46 (95% CI, 0.23-0.83) events per patient-year afterwards. Incidence rate ratios of recurrent ICH after minocycline was lower (0.21 [95% CI, 0.11-0.42], P<0.0001) compared with the year before initiation. Minocycline appeared safe and generally tolerated in a small group of patients with clinically aggressive cerebral amyloid angiopathy and was associated with reduced ICH recurrence. Determining whether this reduction represents a biological response to minocycline rather than a regression to the mean, however, will require a future controlled treatment trial.

Analysis of the prevalence of anticoagulant therapy in patients with cognitive disorders and cerebral amyloid angiopathy (CAA)

To investigate the prevalence of coincident anticoagulation in patients with cognitive disorders and possible or probable cerebral amyloid angiopathy (CAA) as well as the relationship between the presence of oral anticoagulation and CAA-specific lesion load. Patients with subjective cognitive decline (SCD), amnestic and non-amnestic mild cognitive impairment (aMCI/naMCI), Alzheimer's disease (AD), mixed dementia (MD) and vascular dementia (VD) who presented to our outpatient dementia clinic between February 2016 and October 2020 were included in this retrospective analysis. Patients underwent cranial magnetic resonance imaging (MRI). MRI data sets were analyzed regarding the presence of CAA-related MRI biomarkers to determine CAA prevalence. Presence of anticoagulant therapy was determined by chart review. Within the study period, 458 patients (209 male, 249 female, mean age 73.2 ± 9.9years) with SCD (n = 44), naMCI (n = 40), aMCI (n = 182), AD (n = 120), MD (n = 68) and VD (n = 4) were analyzed. Atotal of 109 patients (23.8%) were diagnosed with possible or probable CAA. CAA prevalence was highest in aMCI (39.4%) and MD (28.4%). Of patients with possible or probable CAA, 30.3% were under platelet aggregation inhibition, 12.8% were treated with novel oral anticoagulants and 3.7% received phenprocoumon treatment. Regarding the whole study cohort, patients under oral anticoagulation showed more cerebral microbleeds (p = 0.047). There was no relationship between oral anticoagulation therapy and the frequency of cortical superficial siderosis (p = 0.634). CAA is afrequent phenomenon in older patients with cognitive disorders. Almost half of CAA patients receive anticoagulant therapy. Oral anticoagulation is associated with ahigher number of cortical and subcortical microbleeds.

Abstract TP160: Minimum Intracerebral Hemorrhage Volume to Maximize Diagnostic Accuracy of Simplified Edinburgh Criteria

Introduction: Simplified Edinburgh criteria, based on plain CT, facilitates etiology diagnosis of ICH on cerebral amyloid angiopathy (CAA). Excellent performance in autopsy cohort though, the criteria show disparate discrimination ability amongst survivors with smaller hematoma size in external validation. On assumption that diagnostic accuracy may depend on ICH volume, cutoff volume could likely be found to better the application of Edinburgh criteria. Methods: Primary lobar ICH patients with CT and one of the following: pathology OR qualified MRI available for probable CAA diagnosis per Boston 2.0 criteria were retrospectively enrolled. Clinical characteristics, ICH volume, histology and markers of CT and MRI were collected for validation test. Additionally, likelihood-ratio curves for rule-in and rule-out criteria were plotted, taking 3.0 and 0.3 as the threshold of positive likelihood ratio (PLR) and negative likelihood ratio (NLR) respectively. Results: The criteria were tested among 52 lobar ICH patients with histological proof and 120 with MRI data. Patients with pathology by hematoma evacuation were characterized by larger ICH volume (31.45(31.45), 12.61(16.07), P&lt;0.001) and younger age (67±7, 71±9, P=0.002), compared to those tested on MRI. Discrimination of pathology-evidenced CAA was good (AUC 0.74) for both rule-out (NLR 0.26) and rule-in (PLR 2.97) criteria, while less satisfying when validated against probable CAA on MRI (AUC 0.58, NLR 0.61, PLR 1.42), evincing volume-dependent performance of Edinburgh criteria. According to likelihood-ratio curves (Figure 1), cutoff volume of 30ml may maximize positive likelihood ratio for rule-in criteria and optimize rule-out criteria with NLR≤0.3. Conclusion: Simplified Edinburg criteria was initially validated against pathology- or MRI-attested CAA in Asian population. Dependent on ICH volume, the diagnostic accuracy may be considerably augmented when cutoff value of 30ml was applied.

Abstract 150: Regional Molecular Alterations in Cerebral Amyloid Angiopathy-Related Hemorrhagic Lesions

Background: Previous case reports suggested co-localization of tau but not β-Amyloid with cortical superficial siderosis (cSS) in cerebral amyloid angiopathy (CAA). We thus hypothesized that the tau load represents a continuum with amyloid accumulation in the disease cascade and that the tau load would be higher in lobes with cSS and intracerebral hemorrhages (ICH) when compared to the contralateral lobes without hemorrhages in CAA patients. Methods: The study included 26 cognitively healthy probable CAA patients (mean age 71±7.5, 53.8% male) who underwent multimodal MRI, Pittsburgh compound B (PiB, for amyloid), and 18 F-flortaucipir (FTP, for tau) PET imaging. Mean global cortical PiB uptake and FTP uptake were calculated in each lobar region. The presence of ICH and cSS were identified in each lobar region independent of molecular imaging. A pairwise comparison of PiB and FTP uptake was done between lobes with any hemorrhagic lesion (ICH/cSS) and their corresponding lobes without hemorrhages. Results: The FTP uptake was significantly higher in 8 frontal, 16 temporal, and 11 occipital lobes with hemorrhages compared to their corresponding contralateral lobes without hemorrhages (1.18±0.1 vs. 1.13±0.1; p=0.002, 1.28±0.1 vs. 1.20±0.1; p=0.004, 1.29±0.1 vs. 1.10±0.1; p=0.002, respectively) but not in parietal lobes (p=0.107). The PiB uptake was significantly higher in occipital lobes with hemorrhages compared to their contralateral lobes without hemorrhages (1.41±0.3 vs. 1.35±0.3, p=0.004) but there was no difference in the comparison of amyloid burden for the remaining lobar regions with or without hemorrhage (p&gt;0.2 for all comparisons). Conclusions: Reduced PiB uptake at sites of larger hemorrhagic lesions (cSS/ICH) has been observed in the past so the lack of differences in amyloid between most lobes with and without hemorrhage was not surprising in our study. Our results otherwise show significantly increased tau load at most brain lobes with hemorrhagic lesions among CAA patients. Potential clinical effects of the tau burden related to cSS/ICH should be studied in larger CAA cohorts using appropriate clinical testing.

Association Between Hippocampal Volumes and Cognition in Cerebral Amyloid Angiopathy.

Accumulating evidence suggests that gray matter atrophy, often considered a marker of Alzheimer disease (AD), can also result from cerebral small vessel disease (CSVD). Cerebral amyloid angiopathy (CAA) is a form of sporadic CSVD, diagnosed through neuroimaging criteria, that often co-occurs with AD pathology and leads to cognitive impairment. We sought to identify the role of hippocampal integrity in the development of cognitive impairment in a cohort of patients with possible and probable CAA. Patients were recruited from an ongoing CAA study at Massachusetts General Hospital. Composite scores defined performance in the cognitive domains of memory, language, executive function, and processing speed. Hippocampal subfields' volumes were measured from 3T MRI, using an automated method, and multivariate linear regression models were used to estimate their association with each cognitive domain and relationship to CAA-related neuroimaging markers. One hundred twenty patients, 36 with possible (age mean [range]: 75.6 [65.6-88.9]), 67 with probable CAA (75.9 [59.0-94.0]), and 17 controls without cognitive impairment and CSVD (72.4 [62.5-82.7]; 76.4% female patients), were included in this study. We found a positive association between all investigated hippocampal subfields and memory and language, whereas specific subfields accounted for executive function (CA4 [Estimate = 5.43; 95% CI 1.26-9.61; p = 0.020], subiculum [Estimate = 2.85; 95% CI 0.67-5.02; p = 0.022]), and processing speed (subiculum [Estimate = 1.99; 95% CI 0.13-3.85; p = 0.036]). These findings were independent of other CAA-related markers, which did not have an influence on cognition in this cohort. Peak width of skeletonized mean diffusivity (PSMD), a measure of white matter integrity, was negatively associated with hippocampal subfields' volumes (CA3 [Estimate = -0.012; 95% CI -0.020 to -0.004; p = 0.034], CA4 [Estimate = -0.010; 95% CI -0.020 to -0.0007; p = 0.037], subiculum [Estimate = -0.019; 95% CI -0.042 to -0.0001; p = 0.003]). These results suggest that hippocampal integrity is an independent contributor to cognitive impairment in patients with CAA and that it might be related to loss of integrity in the white matter. Further studies exploring potential causes and directionality of the relationship between white matter and hippocampal integrity may be warranted.

Sensitivity and Specificity of the Boston Criteria Version 2.0 for the Diagnosis of Cerebral Amyloid Angiopathy in a Community-Based Sample.

The Boston criteria are a set of clinical and neuroimaging features that enable accurate diagnosis of cerebral amyloid angiopathy (CAA) without invasive methods such as brain biopsies or autopsy. The last updates to the Boston criteria, named version 2.0, were recently released and incorporated new nonhemorrhagic MRI features. These criteria have been validated in symptomatic samples, with improved diagnostic yield. We set out to investigate the accuracy of the Boston criteria v2.0 for the diagnosis of CAA in a community-based sample. Participants were recruited from longitudinal clinical-pathologic studies of aging conducted at the Rush Alzheimer's Disease Center in Chicago: the Religious Orders Study and the Rush Memory and Aging Project. Deceased participants with in vivo 3T MRI and detailed pathologic data available were included in the analysis. We compared the diagnostic yield of the current and earlier versions of the Boston criteria in our sample. Among those classified as probable CAA according to the Boston criteria v2.0, we investigated the ability of each neuroimaging marker to distinguish between false-positive and true-positive cases. In total, 134 individuals were included in the study (mean age = 82.4 ± 6.0 years; 69.4% F), and 49 of them were considered pathology-proven definite cases with CAA (mean age = 82.9 ± 6.0 years; 63.3% F). The Boston criteria versions 1.0 and 1.5 yielded similar sensitivity (26.5%, both), specificity (90.6% and 89.4%, respectively), and predictive values (negative: 68.1% and 67.9%; positive: 61.9% and 59.1%, respectively). The recently released Boston criteria v2.0 offered higher sensitivity (38.8%) and slightly lower specificity (83.5%). Among those classified as probable CAA (v2.0), pathology-proven true-positive cases had higher numbers of strictly cortical lobar microbleeds compared with false-positive cases (p = 0.004). Similar to findings from symptomatic samples, the inclusion of nonhemorrhagic neuroimaging markers in the updated Boston criteria offered a 12.3% gain in sensitivity among community-dwelling individuals, at the expense of a 5.9% drop in specificity. In cases with probable CAA, the cortical location of microbleeds may represent a promising distinguishing feature between true-positive and false-positive cases. Despite its improved performance, the diagnostic sensitivity of the updated criteria in a community-based sample remains limited. This study provides Class II evidence that the Boston criteria v2.0 accurately distinguishes people with CAA from those without CAA.

The diagnostic accuracy of cerebral amyloid angiopathy criteria between modified Boston criteria v1.5, Boston criteria v2.0, and simplified Edinburgh criteria – the first Thai cerebral amyloid angiopathy pathological confirmed cohort.

AbstractBackgroundThe gold standard of cerebral amyloid angiopathy (CAA) diagnosis are surgical pathology or postmortem examination, which are scarcely done in clinical practice. Thus, the current diagnostic criteria are mainly based on clinic‐radiological characteristics, including modified Boston criteria v1.5 [Linn J, et al. 2010] and Boston criteria v2.0 [Charidimou A, et al. 2022], which are magnetic resonance imaging (MRI)‐based, as well as simplified [Sembill JA, et al. 2022] and full [Rodrigues MA, et al. 2018] Edinburg criteria, which are computerized topography (CT)‐based. These criteria had been developed based on patients in western countries. Therefore, the application of these criteria in Asian population, especially in South‐East Asian, is limited. This study aimed to explore the clinico‐radiological characteristics and the accuracy of the current diagnostic criteria among Thai CAA patients.MethodCongo Red staining brain histopathological specimens in King Chulalongkorn Memorial Hospital, Thailand during 2011‐2021 were reviewed. Patients’ characteristics were gathered from the best available data in electronic medical records. Each clinical event was analyzed separately. Radiological biomarkers in brain CT and MRI which had been done closet to the pathological confirmed date were systematically rated by trained investigators. Level of diagnosis was assessed based on the modified Boston criteria v1.5, Boston criteria v2.0, and simplified Edinburg criteria.ResultEight patients had pathological‐confirmed CAA and 11 clinical events from these patients were reviewed. The clinico‐radiological characteristics are shown in Table 1. Comparisons of the level of diagnosis between the criteria are shown in Table 2 and the diagnostic accuracy of the criteria using the Boston criteria v1.5 and v2.0 as reference standards are summarized in Table 3. The Boston criteria v2.0 revealed the better sensitivity compared with v1.5 (probable CAA, 63.6% vs 54.4%), likely due to an inclusion of non‐hemorrhagic biomarkers; whereas the simplified Edinburgh criteria showed lower sensitivity compared with Boston criteria. The AUC of probable CAA in Boston criteria v1.5 using v2.0 as a reference standard was 0.93 (95%CI[0.76‐1.00], sensitivity 85.7%, and specificity 100%).ConclusionWe performed the application of most recent current diagnostic criteria in CAA Thai population. The larger and well‐designed confirmatory study in Asian cohort is needed.

SWI versus GRE-T2*: Assessing cortical superficial siderosis in advanced cerebral amyloid angiopathy

Background and purposeCortical superficial siderosis (cSS) is a key neuroimaging marker of cerebral amyloid angiopathy (CAA) detected on blood-sensitive magnetic resonance imaging (MRI). We aimed to assess cSS in advanced CAA patients and explore differences in its evaluation between susceptibility weighted imaging (SWI) and gradient recalled echo-T2* (GRE-T2*). Materials and methodsNeuroimaging data gathered from a prospective cohort of CAA patients with probable or definite CAA were retrospectively analyzed by two independent raters. SWI and GRE-T2*were used to assess presence and severity (absent, focal [≤3 sulci] or disseminated [>3 sulci]) of cSS and number of foci. Ratings were compared between sequences and inter-rater agreement was determined. Post hoc analysis explored differences in cSS multifocality scores. ResultsWe detected cSS in 38 patients with SWI and in 36 with GRE-T2* (70.4% versus 66.7%; P=0.5). The two raters agreed in detecting more disseminated cSS when using SWI: 16 focal (29.63%) and 20 disseminated (37.04%) cases of cSS seen on GRE-T2* and 11 (20.37%) focal and 27 (50%) disseminated cSS cases seen using SWI (P=0.008). Inter-rater agreement was equivalent for the two sequences (κpresence 0.7 versus 0.69; κseverity 0.74 versus 0.66) for assessing both presence and severity of cSS. Post hoc analysis showed higher multifocality scores from both raters’ SWI evaluations, with agreement equivalent to that for T2* evaluations. ConclusionsOur findings suggest that SWI ratings could show more disseminated cSS and higher multifocality scores in advanced CAA patients with inter-rater reliability equivalent to that obtained using GRE-T2*, regardless of level of experience.

Histopathological Correlates of Lobar Microbleeds in False-Positive Cerebral Amyloid Angiopathy Cases.

A definite diagnosis of cerebral amyloid angiopathy (CAA), characterized by the accumulation of amyloid β in walls of cerebral small vessels, can only be obtained through pathological examination. A diagnosis of probable CAA during life relies on the presence of hemorrhagic markers, including lobar cerebral microbleeds (CMBs). The aim of this project was to study the histopathological correlates of lobar CMBs in false-positive CAA cases. In 3 patients who met criteria for probable CAA during life, but showed no CAA upon neuropathological examination, lobar CMBs were counted on ex vivo 3T magnetic resonance imaging (MRI) and on ex vivo 7T MRI. Areas with lobar CMBs were next sampled and cut into serial sections, on which the CMBs were then identified. Collectively, there were 25 lobar CMBs on in vivo MRI and 22 on ex vivo 3T MRI of the analyzed hemispheres. On ex vivo MRI, we targeted 12 CMBs for sampling, and definite histopathological correlates were retrieved for 9 of them, of which 7 were true CMBs. No CAA was found on any of the serial sections. The "culprit vessels" associated with the true CMBs instead showed moderate to severe arteriolosclerosis. Furthermore, CMBs in false-positive CAA cases tended to be located more often in the juxtacortical or subcortical white matter than in the cortical ribbon. These findings suggest that arteriolosclerosis can generate lobar CMBs and that more detailed investigations into the exact localization of CMBs with respect to the cortical ribbon could potentially aid the diagnosis of CAA during life. ANN NEUROL 2023;94:856-870.

Cerebral amyloid angiopathy: Neuropathological diagnosis, link to Alzheimer's disease and impact on clinics.

Cerebral amyloid angiopathy (CAA) is the most frequent cause of lobar hemorrhages in the brains of elderly individuals. It is characterized by the deposition of amyloidogenic proteins in the vessel wall of leptomeningeal and/or intracerebral blood vessels. Different proteins can cause CAA. Most frequently, the amyloid β protein (Aβ) is found to be deposited in CAA and indicates a link to Alzheimer's disease, because Aβ is known to be deposited in amyloid plaques characteristic of Alzheimer's disease. Among other proteins that can also cause CAA, transthyretin (TTR) is the most important one because TTR amyloidosis can be successfully treated. Therefore, it is essential to diagnose TTR-related CAA even in biopsies taken in the context of cerebral hematoma evacuations if possible. The current "Boston criteria version 2.0" for the diagnosis of CAA highlight the importance of autopsy for the definite diagnosis of CAA and biopsies for the diagnosis of probable CAA. Here, we discuss the implications of Aβ-related and non-Aβ-related forms of CAA for their current diagnostic relevance also in the context of neurodegenerative diseases as well as the implications of the Boston criteria version 2.0 for neuropathological diagnosis.

Impact of previous statin use on first intracerebral hemorrhage in cerebral amyloid angiopathy

ObjectivesStatins have been associated with an increased risk of spontaneous intracerebral hemorrhage (ICH), but without dedicated study in cerebral amyloid angiopathy (CAA). We aimed to evaluate the association between previous statin treatment and radiological hemorrhagic lesions in a CAA population during a first lobar ICH event. Materials and methodsWe retrospectively included all patients meeting the modified Boston criteria for probable CAA and admitted for a first lobar ICH between 2010 and 2021 at Rouen University Hospital. Patients were classified as having previous statin treatment or not. We compared the ICH volume, the number of associated cerebral microbleeds (CMBs), and cortical superficial siderosis (CSS) according to previous statin treatment or not. We also compared functional outcomes and ICH recurrence during the follow-up period between the two groups. ResultsWe included 99 patients, 27 of whom had statin treatment prior to their ICH. The ICH volume and the number of CMBs did not differ between groups. Disseminated CSS was initially more frequent in the statin group (88% versus 57%; P=0.019), but this was no longer significant after adjustment for antiplatelet treatment (P=0.13). The long-term outcome was similar between the two groups with no increased risk of ICH recurrence in the statin-treated group (29.63% versus 23.61%, P=0.54). ConclusionsPrevious statin treatment was not associated with more severe hemorrhagic lesions in CAA in terms of ICH volume or number of microbleeds, but a trend for increased disseminated CSS was highlighted, which will require further larger studies.

Age-related macular degeneration is associated with probable cerebral amyloid angiopathy: A case-control study

BackgroundAge-related macular degeneration (AMD) is a common retinal degenerative disorder among older individuals. Amyloid deposits, a hallmark of cerebral amyloid angiopathy (CAA), may be involved in the pathogenesis of AMD. Since amyloid deposits may contribute to the development of both AMD and CAA, we hypothesized that patients with AMD have a higher prevalence of CAA. ObjectiveTo compare the prevalence of CAA in patients with or without AMD matched for age. MethodsWe conducted a cross-sectional, 1:1 age-matched, case-control study of patients ≥40 years of age at the Mayo Clinic who had undergone both retinal optical coherence tomography and brain MRI from 2011 to 2015. Primary dependent variables were probable CAA, superficial siderosis, and lobar and deep cerebral microbleeds (CMBs). The relationship between AMD and CAA was assessed using multivariable logistic regression and was compared across AMD severity (none vs early vs late AMD). ResultsOur analysis included 256 age-matched pairs (AMD 126, no AMD 130). Of those with AMD, 79 (30.9%) had early AMD and 47 (19.4%) had late AMD. The mean age was 75±9 years, and there was no significant difference in vascular risk factors between groups. Patients with AMD had a higher prevalence of CAA (16.7% vs 10.0%, p=0.116) and superficial siderosis (15.1% vs 6.2%, p=0.020), but not deep CMB (5.2% vs 6.2%, p=0.426), compared to those without AMD. After adjusting for covariates, having late AMD was associated with increased odds of CAA (OR 2.83, 95% CI 1.10-7.27, p=0.031) and superficial siderosis (OR 3.40, 95%CI 1.20-9.65, p=0.022), but not deep CMB (OR 0.7, 95%CI 0.14-3.51, p=0.669). ConclusionsAMD was associated with CAA and superficial siderosis but not deep CMB, consistent with the hypothesis that amyloid deposits play a role in the development of AMD. Prospective studies are needed to determine if features of AMD may serve as biomarkers for the early diagnosis of CAA.

Plasma amyloid beta 42 is a biomarker for patients with hereditary, but not sporadic, cerebral amyloid angiopathy

BackgroundThe diagnosis of probable cerebral amyloid angiopathy (CAA) is currently mostly based on characteristics of brain MRI. Blood biomarkers would be a cost-effective, easily accessible diagnostic method that may complement diagnosis by MRI and aid in monitoring disease progression. We studied the diagnostic potential of plasma Aβ38, Aβ40, and Aβ42 in patients with hereditary Dutch-type CAA (D-CAA) and sporadic CAA (sCAA).MethodsAll Aβ peptides were quantified in the plasma by immunoassays in a discovery cohort (11 patients with presymptomatic D-CAA and 24 patients with symptomatic D-CAA, and 16 and 24 matched controls, respectively) and an independent validation cohort (54 patients with D-CAA, 26 presymptomatic and 28 symptomatic, and 39 and 46 matched controls, respectively). In addition, peptides were quantified in the plasma in a group of 61 patients with sCAA and 42 matched controls. We compared Aβ peptide levels between patients and controls using linear regression adjusting for age and sex.ResultsIn the discovery cohort, we found significantly decreased levels of all Aβ peptides in patients with presymptomatic D-CAA (Aβ38: p < 0.001; Aβ40: p = 0.009; Aβ42: p < 0.001) and patients with symptomatic D-CAA (Aβ38: p < 0.001; Aβ40: p = 0.01; Aβ42: p < 0.001) compared with controls. In contrast, in the validation cohort, plasma Aβ38, Aβ40, and Aβ42 were similar in patients with presymptomatic D-CAA and controls (Aβ38: p = 0.18; Aβ40: p = 0.28; Aβ42: p = 0.63). In patients with symptomatic D-CAA and controls, plasma Aβ38 and Aβ40 were similar (Aβ38: p = 0.14; Aβ40: p = 0.38), whereas plasma Aβ42 was significantly decreased in patients with symptomatic D-CAA (p = 0.033). Plasma Aβ38, Aβ40, and Aβ42 levels were similar in patients with sCAA and controls (Aβ38: p = 0.092; Aβ40: p = 0.64. Aβ42: p = 0.68).ConclusionsPlasma Aβ42 levels, but not plasma Aβ38 and Aβ40, may be used as a biomarker for patients with symptomatic D-CAA. In contrast, plasma Aβ38, Aβ40, and Aβ42 levels do not appear to be applicable as a biomarker in patients with sCAA.

Comparison of Boston Criteria v2.0/v1.5 for Cerebral Amyloid Angiopathy to Predict Recurrent Intracerebral Hemorrhage.

Intracerebral hemorrhage (ICH) caused by cerebral amyloid angiopathy (CAA) has a high recurrence risk. The Boston criteria, while not designed to predict recurrence, are commonly used for in vivo diagnosis of CAA and have recently been revised to the version 2.0 (v2.0), introducing nonhemorrhagic white matter features. We investigated whether the new v2.0 criteria change ICH recurrence risk in patients with probable CAA. We assessed ICH recurrence risk in consecutive patients with ICH and available brain magnetic resonance imaging. Patients with macrovascular or structural causes were excluded. Recurrent ICH was determined using electronic health records and confirmed by neuroimaging. We compared ICH recurrence risk for Boston criteria v2.0 versus v1.5 for probable CAA using survival analysis. Fifty-nine of 443 patients (13.3%) had recurrent ICH over a median follow-up of 5.7 years (2682 patient-years). Thirty-seven out of one hundred two patients (36.3%) with probable CAA according to the Boston criteria v2.0 had recurrent ICH compared with 36/82 patients (43.9%) according to the v1.5 criteria. Patients with probable CAA according to the Boston v1.5 criteria had a higher ICH recurrence rate (10.9 per 100 person-years [95% CI, 7.8-15.1]) compared with those diagnosed by the v2.0 criteria (8.5 per 100 person-years [95% CI, 6.1-11.7]). The 20 patients defined as probable CAA only by the v2.0 criteria had a very low recurrence rate (0.9 per 100 person-years [95% CI, 0.1-6.7]), lower than those diagnosed using the v1.5 criteria (P<0.001). Our findings suggest a wide spectrum of ICH recurrence risk in patients with probable CAA. Patients with ICH diagnosed with CAA based only on the nonhemorrhagic white matter markers introduced in the Boston v2.0 criteria had a much lower risk of recurrence than those diagnosed with the previous Boston criteria v1.5, comparable to that of patients with ICH not fulfilling any probable CAA criteria.

A comprehensive framework for cerebral amyloid angiopathy diagnosis: Diagnostic accuracy meta-analyses of different biomarkers (S36.008)

<h3>Objective:</h3> We synthesized evidence on the accuracy of different diagnostic approaches for cerebral amyloid angiopathy (CAA), including the clinical-MRI based Boston criteria, amyloid-PET and core CSF biomarkers. <h3>Background:</h3> An accurate non-invasive diagnosis of CAA, an age-related small vessel disease, characterised by progressive deposition of amyloid β in the cerebrovascular wall, is important for clinical decision-making, as well as research in the field. Yet, the diagnostic accuracy and validity of key MRI markers and molecular markers of the disease remain (paradoxically) poorly studied. <h3>Design/Methods:</h3> In a systematic literature search, we identified case-control studies with data relevant for sensitivity/specificity of the Boston criteria, amyloid PET positivity and core CSF biomarkers in symptomatic CAA patients vs. different comparison groups, as applicable. Using a hierarchical (multilevel) logistic regression model we calculated pooled diagnostic test accuracy. <h3>Results:</h3> Five studies had data on the 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. Thirteen amyloid-PET studies (211 CAA, 181 controls) were included in the meta-analysis. The overall pooled sensitivity of amyloid-PET for CAA diagnosis was 80% (95%CI: 67%–84%) and specificity was 82% (95%CI: 71%–86%). Seven studies (153 CAA, 185 Alzheimer’s disease patients), provided data on core CSF biomarkers (Aβ40, Aβ42, t-tau, and p-tau). Aβ40 demonstrated the best overall performance for CAA diagnosis vs Alzheimer’s disease with 80% (95%CI: 68%–83%) pooled sensitivity and 68% (95%CI: 59%–74%) specificity. The core CSF pattern characteristic of CAA was low Aβ40, with intermediate t-tau/p-tau levels (higher than healthy controls, but lower than Alzheimer’s disease) (p &lt; 0.0001 for all comparisons). <h3>Conclusions:</h3> Amyloid-PET and specific CSF patterns of Aβ40, t-tau, and p-tau have moderate-to-good diagnostic accuracy for CAA diagnosis and might supplement the Boston criteria in certain clinical settings (such an approach will be presented at the meeting). <b>Disclosure:</b> Dr. Charidimou has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Imperative Care. Dr. Charidimou has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Elsevier, Journal of Neurological Sciences. Gregoire Boulouis has nothing to disclose.