The Spectrum of Cerebral Small Vessel Disease: Emerging Pathophysiologic Constructs and Management Strategies

Cerebral small vessel disease (CSVD) is a spectrum of disorders that affect small arterioles, venules, cortical and leptomeningeal vessels, perivascular spaces, and the integrity of neurovascular unit, blood brain barrier, and surrounding glia and neurons. CSVD is an important cause of lacunar ischemic stroke and sporadic hemorrhagic stroke, as well as dementia-which will constitute some of the most substantive population and public health challenges over the next century. This article provides an overview of updated pathophysiologic frameworks of CSVD; discusses common and underappreciated clinical and neuroimaging manifestations of CSVD; and reviews emerging genetic risk factors linked to sporadic CSVD.

ACR Appropriateness Criteria® Cerebrovascular Diseases-Stroke and Stroke-Related Conditions

Cerebrovascular disease encompasses a vast array of conditions. The imaging recommendations for stroke-related conditions involving noninflammatory steno-occlusive arterial and venous cerebrovascular disease including carotid stenosis, carotid dissection, intracranial large vessel occlusion, and cerebral venous sinus thrombosis are encompassed by this document. Additional imaging recommendations regarding complications of these conditions including intraparenchymal hemorrhage and completed ischemic strokes are also discussed. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

In-vivo diagnosis of cerebral amyloid angiopathy: an updated review

PURPOSE OF REVIEW

Sporadic cerebral amyloid angiopathy (CAA) is a highly prevalent small vessel disease in ageing population with potential severe complications including lobar intracerebral hemorrhage (ICH), cognitive impairment, and dementia. Although diagnosis of CAA was made only with postmortem neuropathological examination a few decades ago, diagnosing CAA without pathological proof is now allowed in living patients. This review focuses on recently identified biomarkers of CAA and current diagnostic criteria.

RECENT FINDINGS

Over the past few years, clinicians and researchers have shown increased interest for CAA, and important advances have been made. Thanks to recent insights into mechanisms involved in CAA and advances in structural and functional neuroimaging, PET amyloid tracers, cerebrospinal fluid and plasma biomarkers analysis, a growing number of biomarkers of CAA have been identified. Imaging-based diagnostic criteria including emerging biomarkers have been recently developed or updated, enabling accurate and earlier diagnosis of CAA in living patients.

SUMMARY

Recent advances in neuroimaging allow diagnosing CAA in the absence of pathological examination. Current imaging-based criteria have high diagnostic performance in patients presenting with ICH, but is more limited in other clinical context such as cognitively impaired patients or asymptomatic individuals. Further research is still needed to improve diagnostic accuracy.

Prevalence of Clinical and Neuroimaging Markers in Cerebral Amyloid Angiopathy: A Systematic Review and Meta-Analysis

BACKGROUND

Limited data exist regarding the prevalence of clinical and neuroimaging manifestations among patients diagnosed with cerebral amyloid angiopathy (CAA). We sought to determine the prevalence of clinical phenotypes and radiological markers in patients with CAA.

METHODS

Systematic review and meta-analysis of studies including patients with CAA was conducted to primarily assess the prevalence of clinical phenotypes and neuroimaging markers as available in the included studies. Sensitivity analyses were performed based on the (1) retrospective or prospective study design and (2) probable or unspecified CAA status. We pooled the prevalence rates using random-effects models and assessed the heterogeneity using the Cochran Q and I² statistics.

RESULTS

We identified 12 prospective and 34 retrospective studies including 7159 patients with CAA. The pooled prevalence rates were cerebral microbleeds (52% [95% CI, 43%-60%]; I²=93%), cortical superficial siderosis (49% [95% CI, 38%-59%]; I²=95%), dementia or mild cognitive impairment (50% [95% CI, 35%-65%]; I²=97%), intracerebral hemorrhage (ICH; 44% [95% CI, 27%-61%]; I²=98%), transient focal neurological episodes (48%; 10 studies [95% CI, 29%-67%]; I²=97%), lacunar infarcts (30% [95% CI, 25%-36%]; I²=78%), high grades of perivascular spaces located in centrum semiovale (56% [95% CI, 44%-67%]; I²=88%) and basal ganglia (21% [95% CI, 2%-51%]; I²=98%), and white matter hyperintensities with moderate or severe Fazekas score (53% [95% CI, 40%-65%]; I²=91%). The only neuroimaging marker that was associated with higher odds of recurrent ICH was cortical superficial siderosis (odds ratio, 1.57 [95% CI, 1.01-2.46]; I²=47%). Sensitivity analyses demonstrated a higher prevalence of ICH (53% versus 16%; P=0.03) and transient focal neurological episodes (57% versus 17%; P=0.03) among retrospective studies compared with prospective studies. No difference was documented between the prevalence rates based on the CAA status.

CONCLUSIONS

Approximately one-half of hospital-based cohort of CAA patients was observed to have cerebral microbleeds, cortical superficial siderosis, mild cognitive impairment, dementia, ICH, or transient focal neurological episodes. Cortical superficial siderosis was the only neuroimaging marker that was associated with higher odds of ICH recurrence. Future population-based studies among well-defined CAA cohorts are warranted to corroborate our findings.

[Cerebral amyloid angiopathy-related transient focal neurological episodes with diffusion-weighted imaging hyperintense lesions in subcortical white matter and cortical superficial siderosis]

A 72-year-old man presented with two episodes of migratory left-sided paresthesia lasting 10 min. At the first episode, diffusion-weighted imaging hyperintense lesions (DWIHLs) were seen in the right parietal lobe, suggesting an initial diagnosis of acute ischemic stroke, for which we administered antiplatelet therapy for secondary prevention. Four months later, he again developed transient migratory left-sided paresthesia. Gradient-echo T₂*-weighted imaging at this time showed disseminated cortical superficial siderosis (cSS) and strictly cerebral microbleeds around the DWIHLs in the right parietal lobe. These findings led to a diagnosis of cerebral amyloid angiopathy and its related findings, including transient focal neurological episodes (TFNE) and DWIHLs, and antiplatelet medication was stopped. In clinical settings, although it is challenging to distinguish TFNE of hemorrhagic origin from cerebral ischemic symptoms, including transient ischemic attacks, this case suggests that even when elderly patients with transient neurological symptoms present with cortical DWIHLs, paramagnetic-sensitive MRI should be performed to check for cSS around the DWIHLs.

Transient Focal Neurological Events in Cerebral Amyloid Angiopathy and the Long-term Risk of Intracerebral Hemorrhage and Death: A Systematic Review and Meta-analysis

Importance

Transient focal neurological episodes (TFNEs) are a frequently overlooked presentation of cerebral amyloid angiopathy (CAA), a condition with prognostic implications that are still not well described.

Objective

To perform a systematic review and meta-analysis to examine the factors associated with incident lobar intracerebral hemorrhage (ICH) and death in patients with CAA presenting with TFNEs.

Data Sources

A systematic review and individual participant meta-analysis including (1) a hospital-based cohort and (2) the results obtained from a systematic search performed in MEDLINE and Embase completed in December 2019.

Study Selection

Included studies were observational reports of TFNEs. Patient-level clinical, imaging, and prognostic data were required for inclusion. For aggregate data studies, patient-level data were requested. Disagreements were resolved by consensus.

Data Extraction and Synthesis

Data were extracted following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines by 4 independent reviewers. The quality of reports was determined based on the modified Pearson Case Report Quality Scale.

Main Outcomes and Measures

The clinical characteristics of TFNEs, neuroimaging features, and use of antithrombotics during follow-up were considered exposures. The predefined main outcomes were lobar ICH and risk of death during follow-up.

Results

Forty-two studies and 222 CAA-associated TFNE cases were included from the initial 1612 records produced by the systematic search; 26 additional patients (11 men [42.3%]; mean [SD] age, 77 [8] years) were provided by the hospital-based cohort. A total of 108 TFNEs (43.5%) consisted of motor symptoms. Convexity subarachnoid hemorrhage and cortical superficial siderosis were detected in 193 individuals (77.8%) and 156 individuals (62.9%) in the systematic search and hospital-based cohort, respectively. Follow-up duration could be obtained in 185 patients (median duration, 1 year [IQR, 0.8-2.5 years]). During follow-up, symptomatic lobar ICH occurred in 76 patients (39.4%). Motor symptoms (odds ratio, 2.08 [95% CI, 1.16-3.70]) at baseline and antithrombotic use during follow-up (odds ratio, 3.61 [95% CI, 1.67-7.84]) were associated with an increase in risk of lobar ICH. A total of 31 patients (16.5%) died during follow-up; lobar ICH during follow-up and cortical superficial siderosis were the main risk factors for death (odds ratio, 3.01 [95% CI, 1.36-6.69]; odds ratio, 3.20 [95% CI, 1.16-8.91], respectively).

Conclusions and Relevance

Patients presenting with CAA-associated TFNEs are at high risk of lobar ICH and death. Motor TFNEs and use of antithrombotics after a TFNE, in many cases because of misdiagnosis, are risk factors for ICH, and therefore accurate diagnosis and distinguishing this condition from transient ischemic attacks is critical.

Risk of intracranial haemorrhage and ischaemic stroke after convexity subarachnoid haemorrhage in cerebral amyloid angiopathy: international individual patient data pooled analysis

Objective

To investigate the frequency, time-course and predictors of intracerebral haemorrhage (ICH), recurrent convexity subarachnoid haemorrhage (cSAH), and ischemic stroke after cSAH associated with cerebral amyloid angiopathy (CAA).

Methods

We performed a systematic review and international individual patient-data pooled analysis in patients with cSAH associated with probable or possible CAA diagnosed on baseline MRI using the modified Boston criteria. We used Cox proportional hazards models with a frailty term to account for between-cohort differences.

Results

We included 190 patients (mean age 74.5 years; 45.3% female) from 13 centers with 385 patient-years of follow-up (median 1.4 years). The risks of each outcome (per patient-year) were: ICH 13.2% (95% CI 9.9–17.4); recurrent cSAH 11.1% (95% CI 7.9–15.2); combined ICH, cSAH, or both 21.4% (95% CI 16.7–26.9), ischemic stroke 5.1% (95% CI 3.1–8) and death 8.3% (95% CI 5.6–11.8). In multivariable models, there is evidence that patients with probable CAA (compared to possible CAA) had a higher risk of ICH (HR 8.45, 95% CI 1.13–75.5, p = 0.02) and cSAH (HR 3.66, 95% CI 0.84–15.9, p = 0.08) but not ischemic stroke (HR 0.56, 95% CI 0.17–1.82, p = 0.33) or mortality (HR 0.54, 95% CI 0.16–1.78, p = 0.31).

Conclusions

Patients with cSAH associated with probable or possible CAA have high risk of future ICH and recurrent cSAH. Convexity SAH associated with probable (vs possible) CAA is associated with increased risk of ICH, and cSAH but not ischemic stroke. Our data provide precise risk estimates for key vascular events after cSAH associated with CAA which can inform management decisions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-021-10706-3.

Cerebral Amyloid Angiopathy-Related Transient Focal Neurologic Episodes

Transient focal neurologic episodes (TFNEs) are brief disturbances in motor, somatosensory, visual, or language functions that can occur in patients with cerebral amyloid angiopathy (CAA) and may be difficult to distinguish from TIAs or other transient neurologic syndromes. They herald a high rate of future lobar intracerebral hemorrhage, making it imperative to differentiate them from TIAs to avoid potentially dangerous use of antithrombotic drugs. Cortical spreading depression or depolarization triggered by acute or chronic superficial brain bleeding, a contributor to brain injury in other neurologic diseases, may be the underlying mechanism. This review discusses diagnosis, pathophysiology, and management of CAA-related TFNEs.

Intracranial High-Grade Stenosis and Hyperhomocysteinemia Presenting as Cortical Subarachnoid Hemorrhage Concomitant with Acute Ischemic Stroke in a Young Man

BACKGROUND Cortical subarachnoid hemorrhage (cSAH) is a rare clinical presentation with different causes, but rarely happens along with acute ischemic stroke. Intracranial high-grade stenosis originated from brain has been regarded as an unusual cause of cSAH, especially in young adults. CASE REPORT A case of 33-year-old male presented with mild headache and spontaneous left-sided body weakness. Initial brain computed tomography (CT) showed cSAH in the right superior frontal sulcus. Further neuroimaging examinations including magnetic resonance imaging (MRI), digital subtraction angiography (DSA), transesophageal echocardiogram (TEE); in addition, lumbar puncture and blood tests were performed. Diffusion-weighted imaging (DWI) showed an acute infarction in the right frontal lobe and corona radiata of the territory of middle cerebral artery (MCA). The MR angiography (MRA) displayed no flow signal in the right middle cerebral artery M1-segment, while the DSA displayed bloodstream slowness in the right MCA M1-segment which suggested high-grade stenosis of the right MCA. The abnormal laboratory data suggested hyperhomocysteinemia, and excluded causes of thrombosis, infection, or cancer. The mechanism of cSAH may come about in severe atherosclerotic stenosis of MCAs by the broken of expanded tenuous compensatory pial vessels. The patient had good recovered at follow-up. CONCLUSIONS This case demonstrates cSAH with acute ischemic stroke, which is an uncommon complication, in a young adult stroke patient; a high-grade atherosclerotic stenosis of the MCA was identified as the etiology.

[A case of spontaneous intracranial hypotension with transient neurological symptoms]

A 41-year-old woman experienced back pain upon waking up. Immediately afterward, she experienced a continual orthostatic headache. Thereafter, right ear fullness and dizziness also occurred. One month later, she became aware of repeated numbness that started in the right hand and spread to the right half of the body and lower limbs and continued for repeated periods of approximately 20-30 min. Neurological examination revealed no abnormal findings except for orthostatic headache. Electroencephalography showed no epileptic discharge. Head MRI revealed left convexal subarachnoid hemorrhage (cSAH) restricted to the prefrontal sulcus, left frontal cerebral venous thrombosis, diffuse dural thickening with gadolinium enhancement, and subdural hematoma in the posterior cranial fossa. Spinal MRI revealed epidural fluid accumulation around the thoracic spine. CT myelography revealed cerebrospinal fluid leakages at the cervical, thoracic, and lumbar vertebrae levels. The patient was diagnosed with spontaneous intracranial hypotension (SIH), which was treated effectively with a blood patch. In this case, cSAH may have resulted from rupturing of the vessel wall as a result of cortical venous thrombosis induced by SIH. The repeated transient neurologic symptoms suggesting migraine aura may have originated from cSAH, which in turn led to cortical spreading depression. The diagnosis and management of SIH can be often difficult; therefore, repeated migraine-aura-like symptoms are a critical sign of complication with cSAH and cortical venous thrombosis.

One-year prognosis of non-traumatic cortical subarachnoid haemorrhage: A prospective series of 34 patients

INTRODUCTION

Cortical subarachnoid haemorrhage (cSAH) has multiple aetiologies. No prospective study has reported the long-term progression of the condition. The objective of this study is to describe the clinical and aetiological characteristics of patients with cSAH and to gain insight into prognosis.

METHODS

We performed a prospective, observational, multi-centre study. Data on clinical and radiological variables were collected; during a one-year follow-up period, we recorded data on mortality, dependence, rebleeding, and the appearance of dementia.

RESULTS

The study included 34 patients (mean age, 68.3 years; range, 27-89). The most frequent symptoms were headache and focal neurological deficits, which were frequently transient and recurrent. CT scans returned pathological findings in 28 patients (85%). Brain MRI scans were performed in 30 patients (88%), revealing acute ischaemia in 10 (29%), old haemorrhage in 7 (21%), and superficial siderosis in 2 (6%). Aetiology was identified in 26 patients (76.5%): causes were cerebral amyloid angiopathy in 8, ischaemic stroke in 5, vasculitis in 4, reversible posterior encephalopathy in 2, venous thrombosis in 2, reversible cerebral vasoconstriction syndrome in 2, carotid occlusion in 1, Marfan syndrome in 1, and meningeal carcinomatosis in 1. Three patients died during follow-up (2 due to causes related to the cause of cSAH). Three patients developed dementia, 3 had lobar haemorrhages, and one had a second cSAH.

CONCLUSIONS

The most frequent causes of cSAH in our series were cerebral amyloid angiopathy, ischaemic stroke, and vasculitis. This type of haemorrhage has a worse prognosis than other non-aneurysmal cSAH. There are numerous possible causes, and prognosis depends on the aetiology. In elderly patients, intracranial haemorrhage is frequently associated with cognitive impairment.

Pathological examination of cerebral amyloid angiopathy in patients who underwent removal of lobar hemorrhages

Cerebral amyloid angiopathy (CAA) is a degenerative disorder characterized by amyloid-β (Aβ) deposition in the brain microvessels. CAA is also known to contribute not only to cortical microbleeds but also lobar hemorrhages. This retrospective study examined CAA pathologically in patients who underwent direct surgeries for lobar hemorrhage. Thirty-three patients with lobar hemorrhage underwent open surgery with biopsy from 2007 to 2016 in our hospital. Cortical tissues over hematomas obtained surgically were pathologically examined using hematoxylin, eosin stain, and anti-Aβ antibody to diagnose CAA. We also investigated the advanced degree of CAA and clinical features of each patient with lobar hemorrhage. In the 33 patients, 4 yielded specimens that were insufficient to evaluate CAA pathologically. Twenty-four of the remaining 29 patients (82.8%) were pathologically diagnosed with CAA. The majority of CAA-positive patients had moderate or severe CAA based on a grading scale to estimate the advanced degree of CAA. About half of the CAA-positive patients had hypertension, and four took anticoagulant or antiplatelet agents. In five patients who were not pathologically diagnosed with CAA, one had severe liver function disorder, three had uncontrollable hypertension, and one had no obvious risk factor. Our pathological findings suggest that severe CAA with vasculopathic change markedly contributes to lobar hemorrhage. The coexistence of severe CAA and risk factors such as hypertension, anticoagulants or antiplatelets may readily induce lobar hemorrhage.

The increasing impact of cerebral amyloid angiopathy: essential new insights for clinical practice

Cerebral amyloid angiopathy (CAA) has never been more relevant. The last 5 years have seen a rapid increase in publications and research in the field, with the development of new biomarkers for the disease, thanks to advances in MRI, amyloid positron emission tomography and cerebrospinal fluid biomarker analysis. The inadvertent development of CAA-like pathology in patients treated with amyloid-beta immunotherapy for Alzheimer's disease has highlighted the importance of establishing how and why CAA develops; without this information, the use of these treatments may be unnecessarily restricted. Our understanding of the clinical and radiological spectrum of CAA has continued to evolve, and there are new insights into the independent impact that CAA has on cognition in the context of ageing and intracerebral haemorrhage, as well as in Alzheimer's and other dementias. While the association between CAA and lobar intracerebral haemorrhage (with its high recurrence risk) is now well recognised, a number of management dilemmas remain, particularly when considering the use of antithrombotics, anticoagulants and statins. The Boston criteria for CAA, in use in one form or another for the last 20 years, are now being reviewed to reflect these new wide-ranging clinical and radiological findings. This review aims to provide a 5-year update on these recent advances, as well as a look towards future directions for CAA research and clinical practice.

Neuropsychological Effects of Cerebral Amyloid Angiopathy

Cerebral amyloid angiopathy is a condition of the cerebral arterioles and to a lesser extent capillaries and veins, wherein beta-amyloid is deposited. In arterioles, this preferentially targets vascular smooth muscle cells and in the later stages undermines the stability of the vessel. This condition is frequently comorbid with Alzheimer's disease and its role in cognitive impairment and dementia is a topic of considerable recent research. This article reviews recent literature which confirms that CAA independently contributes to cognitive impairment by potentiating the neurodegeneration of Alzheimer's disease, by predisposing to microhemorrhagic and microischemic injury to the brain parenchyma, and by interfering with the autoregulation of CNS blood flow. In this review, we discuss the clinical presentation of cerebral amyloid angiopathy, with a focus on the neuropsychological manifestations of this vasculopathy.

Convexity subarachnoid haemorrhage has a high risk of intracerebral haemorrhage in suspected cerebral amyloid angiopathy

The risk of future symptomatic intracerebral haemorrhage (sICH) remains uncertain in patients with acute convexity subarachnoid haemorrhage (cSAH) associated with suspected cerebral amyloid angiopathy (CAA). We assessed the risk of future sICH in patients presenting to our comprehensive stroke service with acute non-traumatic cSAH due to suspected CAA, between 2011 and 2016. We conducted a systematic search and pooled analysis including our cohort and other published studies including similar cohorts. Our hospital cohort included 20 patients (mean age 69 years; 60% male); 12 (60%) had probable CAA, and 6 (30%) had possible CAA according to the modified Boston criteria; two did not meet CAA criteria because of age <55 years, but were judged likely to be due to CAA. Fourteen patients (70%) had cortical superficial siderosis; 12 (60%) had cerebral microbleeds. Over a mean follow-up period of 19 months, 2 patients (9%) suffered sICH, both with probable CAA (annual sICH risk for probable CAA 8%). In a pooled analysis including our cohort and eight other studies (n = 172), the overall sICH rate per patient-year was 16% (95% CI 11–24%). In those with probable CAA (n = 104), the sICH rate per patient-year was 19% (95% CI 13–27%), compared to 7% (95% CI 3–15%) for those without probable CAA (n = 72). Patients with acute cSAH associated with suspected CAA are at high risk of future sICH (16% per patient-year); probable CAA might carry the highest risk.

Characterizing Deep White Matter Hyperintensities in Patients with Symptomatic Isolated Cortical Superficial Siderosis

BACKGROUND

In patient with cerebral amyloid angiopathy (CAA) presenting with lobar hemorrhage (LH), magnetic resonance imaging (MRI) white matter hyperintensities (WMH) tend to be predominant in posterior regions with the "multiple subcortical spots" WMH pattern as the most frequent topographical WMH pattern. Our aim was to analyze WMH severity and topographical distribution in patients with cortical superficial siderosis (CSS).

METHODS

We retrospectively analyzed MRIs from consecutive symptomatic isolated (i.e., without LH) CSS and LH-CAA (with or without associated CSS) patients. We analyzed baseline clinical characteristics including age, history of hypertension, diabetes, hypercholesterolemia, and pre-existing cognitive deficit. The presence of lobar microbleeds (MB) was scored on T2*. FLAIR (fluid-attenuated inversion recovery) WMH severity (using the Fazekas scale) and topographical distribution (using [slightly modified] earlier described WMH patterns) were analyzed and compared between both groups.

RESULTS

Twenty CSS and 63 LH-CAA patients were analyzed. Baseline clinical characteristics were similar between both groups, except for hypercholesterolemia less frequently present in the CSS group (P = .026). Lobar MB were significantly less frequently present in the CSS group (P < .01), and CSS was more frequently focal in the CSS group compared with LH-CAA patients with associated CSS (P = .03). Mean Fazekas scale was significantly lower in CSS patients (P = .011). WMH patterns did not differ between both groups, with the multiple subcortical spots pattern as the most frequently observed pattern.

CONCLUSIONS

Relative severe WMH scores and similar topographical distribution in CSS patients argue for WMH as a CAA-related feature in these patients with isolated CSS, adding level of evidence that isolated CSS could correspond to early manifestations of CAA.

Cerebral amyloid angiopathy in posttransplant patients with hereditary ATTR amyloidosis

OBJECTIVE

To investigate the prevalence and clinical features of posttransplant CNS symptoms in patients with hereditary ATTR amyloidosis and their Pittsburgh compound B (PiB)-PET imaging correlates.

METHODS

We monitored prevalence and type of CNS symptoms in 53 consecutive posttransplant patients with hereditary ATTR amyloidosis. (11)C-PiB-PET was performed in 15 patients with various disease durations. We also analyzed pathologic and biochemical characteristics of ATTR amyloid deposition in the brain of a posttransplant patient.

RESULTS

Transient focal neurologic episodes (TFNEs) attributed to ATTR-type cerebral amyloid angiopathy (CAA) were found in 11.3% of posttransplant hereditary ATTR amyloidosis patients. TFNE occurred on average 16.8 years after onset of the disease. Patients with longer duration of illness (≥10 years) showed increased (11)C-PiB retention in the brain. The (11)C-PiB accumulation pattern in hereditary ATTR amyloidosis was unique and different from those in Alzheimer disease or Aβ-type CAA. In the autopsy case, ATTR amyloid deposition was mainly localized to leptomeningeal vessels and leptomeninges of the brain. Amyloid fibrils in the brain were almost completely composed of variant transthyretin (TTR).

CONCLUSIONS

TFNE due to ATTR-type CAA occurred frequently in posttransplant patients with long disease durations. (11)C-PiB-PET is a useful diagnostic tool for ATTR-type CAA. ATTR amyloid deposition in the CNS, as measured by PiB-PET, was detected approximately 10 years before onset of TFNE.

Acute Convexity Subarachnoid Hemorrhage Related to Cerebral Amyloid Angiopathy: Clinicoradiological Features and Outcome

BACKGROUND

The specificities of acute convexity subarachnoid hemorrhage (cSAH) related to cerebral amyloid angiopathy (CAA) and its evolution are not well known. We aimed to describe the clinicoradiological pattern, the magnetic resonance imaging (MRI) evolution, and the risk of recurrent bleeding in such patients.

METHODS

Among consecutive patients with an acute nontraumatic cSAH, subjects with available MRI who meet the modified Boston criteria for probable CAA were included. Review of medical records, MRI findings, and follow-up data was performed.

RESULTS

Twenty-three patients (14 women; mean age ± standard deviation: 75.9 ± 7.3 years) were included. cSAH was revealed by transient focal neurological episodes (TFNEs) in 18 of 23 (78.3%) patients. In all patients, acute cSAH appeared as a sulcal fluid-attenuated inversion recovery hyperintensity and GRE T2 hypointensity. Cortical superficial siderosis and cortical microbleeds, respectively, were observed in 21 (91.3%) and 20 (86.9%) patients. Twenty patients (87%) had available follow-up data with a mean duration of 29.8 ± 20.2 months. Recurrent TFNEs occurred in 40% of patients. Acute cSAH evolved into cortical superficial siderosis in all patients. New subarachnoid bleedings defined by recurrent acute cSAH (n = 8) or extension of siderosis (n = 14) were detected in 83.3% of the patients. Lobar intracerebral hemorrhage (ICH) occurred in 7 patients (35%).

CONCLUSION

CAA-related cSAH has a specific pattern defined by a high prevalence of TFNEs and cortical superficial siderosis, with a high risk of recurrent bleeding, either cSAH or lobar ICH. The systematic evolution from cSAH to focal cortical superficial siderosis reveals data on siderosis physiopathology.

Distinguishing clinical and radiological features of non-traumatic convexal subarachnoid hemorrhage

BACKGROUND AND PURPOSE

The full spectrum of causes of convexal subarachnoid hemorrhage (cSAH) requires further investigation. Therefore, our objective was to describe the spectrum of clinical and imaging features of patients with non-traumatic cSAH.

METHODS

A retrospective observational study of consecutive patients with non-traumatic cSAH was performed at a tertiary referral center. The underlying cause of cSAH was characterized and clinical and imaging features that predict a specific etiology were identified. The frequency of future cSAH or intracerebral hemorrhage (ICH) was determined.

RESULTS

In all, 88 patients [median age 64 years (range 25-85)] with non-traumatic cSAH were identified. The most common causes were reversible cerebral vasoconstriction syndrome (RCVS) (26, 29.5%), cerebral amyloid angiopathy (CAA) (23, 26.1%), indeterminate (14, 15.9%) and endocarditis (9, 10.2%). CAA patients commonly presented at an older age than RCVS patients (75 years versus 51 years, P < 0.0001). Thirteen patients (14.7%) had recurrent cSAH, and 12 patients (13.6%) had a subsequent ICH. However, the risk was high amongst those with CAA compared to those caused by RCVS, with recurrent cSAH in 39.1% and subsequent lobar ICH in 43.5% of CAA cases.

CONCLUSIONS

Our study demonstrates the clinical diversity of cSAH. Older age, sensorimotor dysfunction and stereotyped spells suggest CAA as the underlying cause. Younger age and thunderclap headache predict RCVS. Yet, various other causes also need to be considered in the differential diagnosis.

Spontaneous subarachnoid hemorrhage and negative initial vascular imaging--should further investigation depend upon the pattern of hemorrhage on the presenting CT?

BACKGROUND

Multiple investigations are usually performed in patients with spontaneous SAH who have negative initial angiography. This study aimed to evaluate the most appropriate use of additional imaging studies and how this may be influenced by the findings of the initial CT.

METHODS

A retrospective analysis was performed on a prospectively collected cohort of patients referred with spontaneous SAH and negative initial angiography. The patients were divided into four categories based upon the distribution of blood on the initial CT: perimesencephalic (pSAH), diffuse (dSAH), sulcal (sSAH) and CT negative (CSF positive for xanthochromia) (nCT-pLP). The number and nature of the subsequent imaging investigations were reviewed, and the results were correlated with the findings of the presenting CT.

RESULTS

One hundred fourteen patients were included in the study. Repeat imaging found five relevant abnormalities. Three cases of vasculitis were diagnosed on the first DSA following a negative CTA. A case of dissecting aneurysm was revealed on the third neurovascular study. A hemorrhagic spinal tumor presented with xanthochromia. No subsequent abnormality was found on the third DSA or MRI head. No case of pSAH had a subsequent positive finding if the initial CTA was negative.

CONCLUSIONS

Certain patterns of SAH are associated with a low yield of abnormalities on repeat imaging if the initial angiography is normal. The authors believe that the pattern of hemorrhage on the presenting CT should be used to guide the most appropriate use of further imaging modalities and present a diagnostic algorithm for this purpose.

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: 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.

Cerebral amyloid angiopathy causing large contralateral hemorrhage during surgery for lobar hemorrhage: a case report

We report a rare case of cerebral amyloid angiopathy (CAA) causing large contralateral hemorrhage during surgery for lobar hemorrhage. A 62-year-old woman presented with lobar hemorrhage in the left frontal and parietal lobes recurring over the previous 1 month. Because we could not detect the origin of the lobar hemorrhage, we performed a biopsy around the lobar hemorrhage site with the removal of a hematoma. During the surgery, we identified acute brain swelling without bleeding from the operative field. Intraoperative computed tomography demonstrated new large lobar hemorrhage of the right parietal lobe, which we could promptly remove. Specimens around hematomas on both sides were pathologically diagnosed as CAA on immunohistochemical examination. After the surgery, she suffered from lobar hemorrhage three times in the space of only 3 months. To the best of our knowledge, there has been no reported case of CAA causing intracranial hemorrhage of another lesion during surgery. Neurosurgeons should know a possibility of intraoperative hemorrhage in surgeries for lobar hemorrhage caused by CAA.

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.

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.

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.