Cortical superficial siderosis and intracerebral hemorrhage risk in cerebral amyloid angiopathy

Diagnostic Significance of Cortical Superficial Siderosis for Alzheimer Disease in Patients with Cognitive Impairment

BACKGROUND AND PURPOSE

Because the diagnostic significance of cortical superficial siderosis for Alzheimer disease and the association between cortical superficial siderosis and the topographic distribution of cerebral microbleeds have been unclear, we investigated the association between cortical superficial siderosis and clinicoradiologic characteristics of patients with cognitive impairment.

MATERIALS AND METHODS

We studied 347 patients (217 women, 130 men; mean age, 74 ± 9 years) who visited our memory clinic and underwent MR imaging (3T SWI). We analyzed the association between cortical superficial siderosis and the topographic distribution of cerebral microbleeds plus clinical characteristics including types of dementia. We used multivariate logistic regression analysis to determine the diagnostic significance of cortical superficial siderosis for Alzheimer disease.

RESULTS

Twelve patients (3.5%) manifested cortical superficial siderosis. They were older (P = .026) and had strictly lobar cerebral microbleeds significantly more often than did patients without cortical superficial siderosis (50.0% versus 19.4%, P = .02); the occurrence of strictly deep and mixed cerebral microbleeds, however, did not differ in the 2 groups. Alzheimer disease was diagnosed in 162 (46.7%) patients. Of these, 8 patients (4.9%) had cortical superficial siderosis. In the multivariate logistic regression analysis for the diagnosis of Alzheimer disease, lacunar infarcts were negatively and independently associated with Alzheimer disease (P = .007).

CONCLUSIONS

Although cortical superficial siderosis was associated with a strictly lobar cerebral microbleed location, it was not independently associated with Alzheimer disease in a memory clinic setting. Additional studies are required to investigate the temporal changes of these cerebral amyloid angiopathy-related MR imaging findings.

Cortical superficial siderosis: detection and clinical significance in cerebral amyloid angiopathy and related conditions

Cortical superficial siderosis describes a distinct pattern of blood-breakdown product deposition limited to cortical sulci over the convexities of the cerebral hemispheres, sparing the brainstem, cerebellum and spinal cord. Although cortical superficial siderosis has many possible causes, it is emerging as a key feature of cerebral amyloid angiopathy, a common and important age-related cerebral small vessel disorder leading to intracerebral haemorrhage and dementia. In cerebral amyloid angiopathy cohorts, cortical superficial siderosis is associated with characteristic clinical symptoms, including transient focal neurological episodes; preliminary data also suggest an association with a high risk of future intracerebral haemorrhage, with potential implications for antithrombotic treatment decisions. Thus, cortical superficial siderosis is of relevance to neurologists working in neurovascular, memory and epilepsy clinics, and neurovascular emergency services, emphasizing the need for appropriate blood-sensitive magnetic resonance sequences to be routinely acquired in these clinical settings. In this review we focus on recent developments in neuroimaging and detection, aetiology, prevalence, pathophysiology and clinical significance of cortical superficial siderosis, with a particular emphasis on cerebral amyloid angiopathy. We also highlight important areas for future investigation and propose standards for evaluating cortical superficial siderosis in research studies.

Contribution of convexal subarachnoid hemorrhage to disease progression in cerebral amyloid angiopathy

BACKGROUND AND PURPOSE

Cerebral amyloid angiopathy-related cortical superficial siderosis (cSS) seems to indicate an increased risk of subsequent intracerebral hemorrhage (ICH). We wanted to identify the mechanisms and sequence of hemorrhagic events which are responsible for this association.

METHODS

During a 9-year-period, we identified patients with spontaneous convexal subarachnoid hemorrhage (cSAH) and performed a careful longitudinal analysis of clinical and neuroimaging data. A close imaging-histopathologic correlation was performed in one patient.

RESULTS

Of 38 cSAH patients (mean age, 77±11 years), 29 (76%) had imaging features of cerebral amyloid angiopathy on baseline magnetic resonance imaging. Twenty-six (68%) had cSS. Sixteen subjects underwent postcontrast magnetic resonance imaging. Extravasation of gadolinium at the site of the acute cSAH was seen on all postcontrast scans. After a mean of 24±22 (range 1-78) months of follow-up, 15 (39%) had experienced recurrent cSAHs and 14 (37%) had suffered lobar ICHs. Of 22 new ICHs, 17 occurred at sites of previous cSAHs or cSS. Repeated neuroimaging showed expansion of cSAH into the brain parenchyma and evolution of a lobar ICH in 4 patients. Propagation of cSS was observed in 21 (55%) patients, with 14 of those having experienced recurrent cSAHs. In the autopsy case, leakage of meningeal vessels affected by cerebral amyloid angiopathy was noted.

CONCLUSIONS

In cerebral amyloid angiopathy, leakage of meningeal vessels seems to be a major cause for recurrent intrasulcal bleedings, which lead to the propagation of cSS and indicate sites with increased vulnerability for future ICH. Intracerebral bleedings may also develop directly from or in extension of a cSAH.

Amyloid spells and high blood pressure: imminent danger?

We present the case of a 71-year-old male, admitted after a generalized tonic-clonic seizure, with a history of recurrent left arm and face paresthesias, associated with sulcal cortical subarachnoid hemorrhages. During the next 48 h, he remained agitated with a high blood pressure profile; he also suffered a cardiac arrest in relation to a severe left fronto-parietal and a smaller right parietal parenchymal hemorrhage that developed over the subarachnoid hemorrhage locations. There were no intracranial vascular abnormalities. Three months later, an MRI revealed disseminated superficial siderosis. He was discharged with a modified Rankin scale of 4. He died 1 month later of unknown cause. A diagnosis of probable cerebral amyloid angiopathy was assumed. Patients with pathologically proven cerebral amyloid angiopathy that present with transient focal neurological symptoms in relation to cortical bleeds, the so-called ‘myloid spells’ seem to be at an increased risk of future parenchymal hemorrhages. Avoiding antiplatelet agents in these cases has been proposed. Our case suggests that these patients should be monitored closely in the hyperacute phase, and tight blood pressure control should be considered as the immediate risk of bleeding may be high, even without a definitive diagnosis of cerebral amyloid angiopathy.

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.

Cerebral amyloid angiopathy with and without hemorrhage: evidence for different disease phenotypes

OBJECTIVE

To gain insight into different cerebral amyloid angiopathy (CAA) phenotypes and mechanisms, we investigated cortical superficial siderosis (CSS), a new imaging marker of the disease, and its relation with APOE genotype in patients with pathologically proven CAA, who presented with and without intracerebral hemorrhage (ICH).

METHODS

MRI scans of 105 patients with CAA pathologic confirmation and MRI were analyzed for CSS (focal, ≤3 sulci; disseminates, ≥4 sulci) and other imaging markers. We compared pathologic, imaging, and APOE genotype data between subjects with vs without ICH, and investigated associations between CSS and APOE genotype.

RESULTS

Our cohort consisted of 54 patients with CAA with symptomatic lobar ICH and 51 without ICH. APOE genotype was available in 53 patients. More than 90% of pathology samples in both groups had neuritic plaques, whereas neurofibrillary tangles were more commonly present in the patients without ICH (87% vs 42%, p < 0.0001). There was a trend for patients with CAA with ICH to more commonly have APOE ε2 (48.7% vs 21.4%, p = 0.075), whereas patients without ICH were more likely to be APOE ε4 carriers (85.7% vs 53.9%, p = 0.035). Disseminated CSS was considerably commoner in patients with ICH (33.3% vs 5.9%, p < 0.0001). In logistic regression, disseminated CSS was associated with APOE ε2 (but not APOE ε4) (odds ratio 5.83; 95% confidence interval 1.49-22.82, p = 0.011).

CONCLUSIONS

This neuropathologically defined CAA cohort suggests that CSS and APOE ε2 are related to the hemorrhagic expression of the disease; APOE ε4 is enriched in nonhemorrhagic CAA. Our study emphasizes the concept of different CAA phenotypes, suggesting divergent pathophysiologic mechanisms.

Cerebral amyloid angiopathy: emerging concepts

Cerebral amyloid angiopathy (CAA) involves cerebrovascular amyloid deposition and is classified into several types according to the amyloid protein involved. Of these, sporadic amyloid β-protein (Aβ)-type CAA is most commonly found in older individuals and in patients with Alzheimer's disease (AD). Cerebrovascular Aβ deposits accompany functional and pathological changes in cerebral blood vessels (CAA-associated vasculopathies). CAA-associated vasculopathies lead to development of hemorrhagic lesions [lobar intracerebral macrohemorrhage, cortical microhemorrhage, and cortical superficial siderosis (cSS)/focal convexity subarachnoid hemorrhage (SAH)], ischemic lesions (cortical infarction and ischemic changes of the white matter), and encephalopathies that include subacute leukoencephalopathy caused by CAA-associated inflammation/angiitis. Thus, CAA is related to dementia, stroke, and encephalopathies. Recent advances in diagnostic procedures, particularly neuroimaging, have enabled us to establish a clinical diagnosis of CAA without brain biopsies. Sensitive magnetic resonance imaging (MRI) methods, such as gradient-echo T2^* imaging and susceptibility-weighted imaging, are useful for detecting cortical microhemorrhages and cSS. Amyloid imaging with amyloid-binding positron emission tomography (PET) ligands, such as Pittsburgh Compound B, can detect CAA, although they cannot discriminate vascular from parenchymal amyloid deposits. In addition, cerebrospinal fluid markers may be useful, including levels of Aβ40 for CAA and anti-Aβ antibody for CAA-related inflammation. Moreover, cSS is closely associated with transient focal neurological episodes (TFNE). CAA-related inflammation/angiitis shares pathophysiology with amyloid-related imaging abnormalities (ARIA) induced by Aβ immunotherapies in AD patients. This article reviews CAA and CAA-related disorders with respect to their epidemiology, pathology, pathophysiology, clinical features, biomarkers, diagnosis, treatment, risk factors, and future perspectives.

Late-life migraine accompaniments: A narrative review

BACKGROUND

Migraine is one of the most common chronic neurological disorders. In 1980, C. Miller Fisher described late-life migraine accompaniments as transient neurological episodes in older individuals that mimic transient ischemic attacks. There has not been an update on the underlying nature and etiology of late-life migraine accompanimentsd since the original description.

PURPOSE

The purpose of this article is to provide a comprehensive and extensive review of the late-life migraine accompaniments including the epidemiology, clinical characteristics, differential diagnosis, and treatment.

METHODS

Literature searches were performed in MEDLINE®, PubMed, Cochrane Library, and EMBASE databases for publications from 1941 to July 2014. The search terms "Migraine accompaniments," "Late life migraine," "Migraine with aura," "Typical aura without headache," "Migraine equivalents," "Acephalic migraine," "Elderly migraine," and "Transient neurological episodes" were used.

CONCLUSION

Late-life onset of migraine with aura is not rare in clinical practice and can occur without headache, especially in elderly individuals. Visual symptoms are the most common presentation, followed respectively by sensory, aphasic, and motor symptoms. Gradual evolution, the march of transient neurological deficits over several minutes and serial progression from one symptom to another in succession are typical clinical features for late-life migraine accompaniments. Transient neurological disturbances in migraine aura can mimic other serious conditions and can be easily misdiagnosed. Careful clinical correlation and appropriate investigations are essential to exclude secondary causes. Treatments are limited and still inconsistent.

The overlap between vascular disease and Alzheimer's disease--lessons from pathology

Recent epidemiological and clinico-pathological data indicate considerable overlap between cerebrovascular disease (CVD) and Alzheimer's disease (AD) and suggest additive or synergistic effects of both pathologies on cognitive decline. The most frequent vascular pathologies in the aging brain and in AD are cerebral amyloid angiopathy and small vessel disease. Up to 84% of aged subjects show morphological substrates of CVD in addition to AD pathology. AD brains with minor CVD, similar to pure vascular dementia, show subcortical vascular lesions in about two-thirds, while in mixed type dementia (AD plus vascular dementia), multiple larger infarcts are more frequent. Small infarcts in patients with full-blown AD have no impact on cognitive decline but are overwhelmed by the severity of Alzheimer pathology, while in early stages of AD, cerebrovascular lesions may influence and promote cognitive impairment, lowering the threshold for clinically overt dementia. Further studies are warranted to elucidate the many hitherto unanswered questions regarding the overlap between CVD and AD as well as the impact of both CVD and AD pathologies on the development and progression of dementia.

Interrelationship of superficial siderosis and microbleeds in cerebral amyloid angiopathy

OBJECTIVE

We sought to explore the mechanisms leading to cerebral amyloid angiopathy (CAA)-related cortical superficial siderosis (cSS) by examining its neuroimaging and genetic association with cerebral microbleeds (CMBs).

METHODS

MRI scans of 84 subjects with probable or definite CAA participating in a longitudinal research study were graded for cSS presence and severity (focal, restricted to ≤ 3 sulci vs disseminated, ≥ 4 sulci), and CMB count. APOE ε variants were directly genotyped. We performed cross-sectional analysis comparing CMB counts and APOE ε2 and ε4 allele frequency between subjects with no, focal, or disseminated cSS.

RESULTS

cSS was present in 48% (n = 40) of the population. APOE ε2 was overrepresented among participants with focal (odds ratio [OR] 7.0, 95% confidence interval [CI] 1.7-29.3, p = 0.008) and disseminated (OR 11.5, 95% CI 2.8-46.2, p = 0.001) cSS relative to individuals without cSS. CMB counts decreased with increasing severity of cSS (median: 41, 38, and 15 for no cSS, focal cSS, and disseminated cSS, respectively, p = 0.09). The highest CMB count tertile was associated with APOE ε4 (OR 3.0, 95% CI 1.4-6.6, p = 0.006) relative to the lowest tertile.

CONCLUSIONS

Among individuals with advanced CAA, cSS tends to occur in individuals with relatively lower CMB counts and with a distinct pattern of APOE genotypes. These results suggest that CAA-related cSS and CMBs may arise from distinct vasculopathic mechanisms.

Clinical associations of cerebral microbleeds on magnetic resonance neuroimaging

Susceptibility-weighted and gradient-recalled echo T2* magnetic resonance imaging have enabled the detection of very small foci of blood within the brain, which have been termed "cerebral microbleeds." These petechial intraparenchymal hemorrhages have begun to emerge as diagnostically and prognostically useful markers in a variety of disease states. Severe hypertension and cerebral amyloid angiopathy are perhaps the best established microhemorrhagic conditions from neuroimaging literature; however, many others are also recognized including cerebral autosomal dominant arteriopathy, subcortical infarcts, and leukoencephalopathy (CADASIL), moyamoya disease, fat embolism, cerebral malaria, and infective endocarditis. Microbleeds are also a common finding in the setting of trauma and stroke. The purpose of this review is to broadly describe the neuroimaging of cerebral microbleeds in a wide variety of conditions, including the differences in their appearance and distribution in different disease states. In a few situations, the presence of microbleeds may influence clinical management, and we discuss these situations in detail. The major importance of this emerging field in neuroimaging is the potential to identify microvascular pathology at an asymptomatic or minimally symptomatic stage and create a window of therapeutic opportunity.

Pathogenetical Subtypes of Recurrent Intracerebral Hemorrhage

Background and Purpose—

Pathogenetic classification of intracerebral hemorrhage (ICH), using systems such as SMASH-U (structural vascular lesions, medication, cerebral amyloid angiopathy [CAA], systemic disease, hypertension, or undetermined), is important in predicting functional outcomes and mortality in patients with ICH. This study aimed to compare pathogenetic subtypes between the first and recurrent ICH.

Methods—

This study obtained data related to 4578 consecutive acute patients with ICH from the National Taiwan University Hospital Stroke Registry during January 1995 to December 2013. Using the SMASH-U method, patients were classified into 6 subtypes. We then analyzed the outcomes of first-ever ICH cases and pathogenetic classification of recurrent ICH.

Results—

Among 3785 patients who experienced first-ever ICH (male, 63.3%; mean age, 58.7±17.0 years), the most common cause was hypertensive angiopathy (54.9%), followed by CAA (12.2%), systemic disease (12.1%), undetermined (10.1%), structural vascular lesions (7.8%), and medication related (2.9%). In 185 cases of recurrent ICH, pathogenetic differences between the 2 ICH events were observed in 34 (18.4%) cases, most of which were CAA to hypertensive angiopathy (n=10) or vice versa (n=7). The rates of ICH recurrence were highest for systemic disease-related and CAA-related ICH at 1, 5, 10, and 15 years after the indexed ICH event.

Conclusions—

In approximately one fifth of the recurrent patients with ICH, pathogenetic differences were observed between initial and recurrent events, particularly among those with CAA. It is possible that some patients with ICH with concomitant hypertensive angiopathy and CAA may have been categorized as CAA by the SMASH-U method.

White matter perivascular spaces are related to cortical superficial siderosis in cerebral amyloid angiopathy

BACKGROUND AND PURPOSE

We set out to investigate whether MRI-visible centrum semiovale perivascular spaces (CSO-PVS), a potential biomarker of impaired interstitial fluid drainage in sporadic cerebral amyloid angiopathy, is associated with cortical superficial siderosis (cSS), reflecting recurrent hemorrhage from severe leptomeningeal and superficial cortical vascular amyloid.

METHODS

Retrospective multicenter cohort study of possible/probable cerebral amyloid angiopathy according to the Boston criteria. PVS were rated in basal ganglia and CSO (CSO-PVS) on axial T2-weighted sequences, using a validated 4-point visual rating scale and were classified as high (score>2) or low degree (score≤2) for prespecified analyses. Independent risk factors for high CSO-PVS degree were investigated in logistic regression.

RESULTS

The final cohort consisted of 138 cerebral amyloid angiopathy patients (mean age, 71.8 years; 95% confidence interval, 70.2-73.4 years; 52.2% men). High CSO-PVS degree was present in 61.2% of cases. The prevalence of any cSS, and disseminated cSS (involving >3 sulci), was higher in patients with high versus low CSO-PVS degree (for any cSS 45.9% versus 13.5%; P<0.00005; for disseminated cSS 31.8% versus 0%; P<0.00005). In multivariable logistic regression analysis, cSS presence (odds ratio, 4.78; 95% confidence interval, 1.64-13.87; P=0.004) was an independent predictors of high CSO-PVS degree. We found no associations between basal ganglia PVS and cSS.

CONCLUSIONS

High degree of CSO-PVS is highly prevalent in sporadic cerebral amyloid angiopathy and is related to cSS. Our findings suggest that severe leptomeningeal and cortical vascular amyloid (causing cSS) is related to impaired interstitial fluid drainage from cerebral white matter, although determining the causal direction of this relationship requires prospective studies.

Focal subarachnoid haemorrhage mimicking transient ischaemic attack--do we really need MRI in the acute stage?

Background

Acute non-traumatic focal subarachnoid haemorrhage (fSAH) is a rare transient ischaemic attack (TIA)-mimic. MRI is considered to be indispensable by some authors in order to avoid misdiagnosis, and subsequent improper therapy. We therefore evaluated the role of CT and MRI in the diagnosis of fSAH patients by comparing our cases to those from the literature.

Methods

From 01/2010 to 12/2012 we retrospectively identified seven patients with transient neurological episodes due to fSAH, who had received unenhanced thin-sliced multiplanar CT and subsequent MRI within 3 days on a 1.5 T scanner. MRI protocol included at least fast-field-echo (FFE), diffusion-weighted imaging (DWI), T2-weighted fluid-attenuated inversion recovery (FLAIR) and time-of-flight (TOF) MRA sequences. By using MRI as gold-standard, we re-evaluated images and data from recent publications regarding the sensitivity to detect fSAH in unenhanced CT.

Results

fSAH was detected by CT and by FFE and FLAIR on MRI in all of our own cases. However, DWI and T2w-spin-echo sequences revealed fSAH in 3 of 7 and 4 of 6 cases respectively. Vascular imaging was negative in all cases. FFE-MRI revealed additional multiple microbleeds and superficial siderosis in 4 of 7 patients and 5 of 7 patients respectively. Including data from recently published literature CT scans delivered positive results for fSAH in 95 of 100 cases (95%), whereas MRI was positive for fSAH in 69 of 69 cases (100%).

Conclusions

Thin-sliced unenhanced CT is a valuable emergency diagnostic tool to rule out intracranial haemorrhage including fSAH in patients with acute transient neurological episodes if immediate MRI is not available. However, MRI work-up is crucial and mandatorily has to be completed within the next 24–72 hours.

Outcome markers for clinical trials in cerebral amyloid angiopathy

Efforts are underway for early-phase trials of candidate treatments for cerebral amyloid angiopathy, an untreatable cause of haemorrhagic stroke and vascular cognitive impairment. A major barrier to these trials is the absence of consensus on measurement of treatment effectiveness. A range of potential outcome markers for cerebral amyloid angiopathy can be measured against the ideal criteria of being clinically meaningful, closely representative of biological progression, efficient for small or short trials, reliably measurable, and cost effective. In practice, outcomes tend either to have high clinical salience but low statistical efficiency, and thus more applicability for late-phase studies, or greater statistical efficiency but more limited clinical meaning. The most statistically efficient markers might be those that are potentially reversible with treatment, although their clinical significance remains unproven. Many of the candidate outcomes for cerebral amyloid angiopathy trials are probably applicable also to other small-vessel brain diseases.