Brain atrophy and neuropsychological outcome after treatment of ruptured anterior cerebral artery aneurysms: a voxel-based morphometric study

Considering Psychological and Cognitive Factors in Interventional Neuroradiology: A Systematic Literature Review

BACKGROUND

Interventional neuroradiology is a relatively recent discipline that diagnoses and treats cerebral vascular diseases. However, specific literature on cognitive and psychological domains of patients undergoing interventional neuroradiology procedures is limited.

PURPOSE

Our aim was to review the existent literature on cognitive and psychological domains in patients undergoing interventional neuroradiology procedures to raise clinicians' awareness of their mental status.

DATA SOURCES

Articles were searched in PubMed, EMBASE, and Scopus from 2000 to 2022 using terms such as "interventional neuroradiology," "psychology," and "cognition" according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

STUDY SELECTION

Of 1483 articles in English, 64 were included and analyzed. Twelve focused on psychological aspects; 52, on cognitive ones.

DATA ANALYSIS

Regarding psychological aspects, it appears that early psychological consultations and "nonpharmacologic" strategies can impact the anxiety and depression of patients undergoing endovascular procedures. Regarding cognitive aspects, it appears that endovascular treatment is safe and generates similar or even fewer cognitive deficits compared with analogous surgical procedures.

DATA SYNTHESIS

Among the 12 articles on psychological aspects, 6/12 were retrospective with one, while 6/12 were prospective. Among the 52 articles on cognitive aspects, 7/54 were retrospective, while 45/52 were prospective.

LIMITATIONS

The main limitation derives from the inhomogeneity of the cognitive and psychological assessment tools used in the articles included in our analysis.

CONCLUSIONS

Our review highlights the need to include cognitive and psychological assessments in clinical practice in case patients eligible for interventional neuroradiology procedures. In the future, much more research of and attention to cognitive and psychologic aspects of neurovascular disease is needed. Systematic incorporation of strategies and tools to access and address pre, peri-, and postprocedural psychological and cognitive components could have major benefits in patient satisfaction, recovery, and the success of endovascular practice.

Resolution of Cerebral Inflammation Following Subarachnoid Hemorrhage

BACKGROUND

Aneurismal subarachnoid hemorrhage (SAH) is a type of hemorrhagic stroke that, despite improvement through therapeutic interventions, remains a devastating cerebrovascular disorder that has a high mortality rate and causes long-term disability. Cerebral inflammation after SAH is promoted through microglial accumulation and phagocytosis. Furthermore, proinflammatory cytokine release and neuronal cell death play key roles in the development of brain injury. The termination of these inflammation processes and restoration of tissue homeostasis are of utmost importance regarding the possible chronicity of cerebral inflammation and the improvement of the clinical outcome for affected patients post SAH. Thus, we evaluated the inflammatory resolution phase post SAH and considered indications for potential tertiary brain damage in cases of incomplete resolution.

METHODS

Subarachnoid hemorrhage was induced through endovascular filament perforation in mice. Animals were killed 1, 7 and 14 days and 1, 2 and 3 months after SAH. Brain cryosections were immunolabeled for ionized calcium-binding adaptor molecule-1 to detect microglia/macrophages. Neuronal nuclei and terminal deoxyuridine triphosphate-nick end labeling staining was used to visualize secondary cell death of neurons. The gene expression of various proinflammatory mediators in brain samples was analyzed by quantitative polymerase chain reaction.

RESULTS

We observed restored tissue homeostasis due to decreased microglial/macrophage accumulation and neuronal cell death 1 month after insult. However, the messenger RNA expression levels of  interleukin 6  and  tumor necrosis factor α were still elevated at 1 and 2 months post SAH, respectively. The gene expression of interleukin 1β reached its maximum on day 1, whereas at later time points, no significant differences between the groups were detected.

CONCLUSIONS

By the herein presented molecular and histological data we provide an important indication for an incomplete resolution of inflammation within the brain parenchyma after SAH. Inflammatory resolution and the return to tissue homeostasis represent an important contribution to the disease's pathology influencing the impact on brain damage and outcome after SAH. Therefore, we consider a novel complementary or even superior therapeutic approach that should be carefully rethought in the management of cerebral inflammation after SAH. An acceleration of the resolution phase at the cellular and molecular levels could be a potential aim in this context.

Modern Imaging of Aneurysmal Subarachnoid Hemorrhage

In this review, we discuss the imaging of aneurysmal subarachnoid hemorrhage (SAH). We discuss emergency brain imaging, aneurysm detection techniques, and the management of CTA-negative SAH. We also review the concepts of cerebral vasospasm and delayed cerebral ischemia that occurs after aneurysm rupture and their impact on patient outcomes. These pathologies are distinct, and the use of multimodal imaging modalities is essential for prompt diagnosis and management to minimize morbidity from these conditions. Lastly, new advances in artificial intelligence and advanced imaging modalities such as PET and MR imaging scans have been shown to improve the detection of aneurysms and potentially predict outcomes early in the course of SAH.

Altered hippocampal functional connectivity after the rupture of anterior communicating artery aneurysm

BACKGROUND AND PURPOSE

Aneurysmal subarachnoid hemorrhage (SAH) predisposes hippocampal injury, a major cause of follow-up cognitive impairment. Our previous study has revealed an abnormal resting-state brain network in patients after the rupture of anterior communicating artery (ACoA) aneurysm. However, the functional connectivity (FC) characteristics of the hippocampus and its relationship with cognitive performance in these patients remain unknown.

METHODS

This study ultimately included 26 patients and 19 age- and sex-matched controls who completed quality control for resting-state functional magnetic resonance imaging (fMRI). The mean time series for each side of the hippocampus was extracted from individuals and then a seed-to-voxel analysis was performed. We compared the difference in FC strength between the two groups and subsequently analyzed the correlations between abnormal FC and their cognitive performance.

RESULTS

The results of bilateral hippocampus-based FC analysis were largely consistent. Compared with the healthy controls, patients after the rupture of ACoA aneurysm exhibited significantly decreased FC between the hippocampus and other brain structures within the Papez circuit, including bilateral anterior and middle cingulate cortex (MCC), bilateral medial superior frontal gyrus, and left inferior temporal gyrus (ITG). Instead, increased FC between the hippocampus and bilateral insula was observed. Correlation analyses showed that more subjective memory complaints or lower total cognitive scores were associated with decreased connectivity in the hippocampus and several brain regions such as left anterior cingulate cortex (ACC) and frontotemporal cortex.

CONCLUSION

These results extend our previous findings and suggest that patients with ruptured ACoA aneurysm exist hypoconnectivity between the hippocampus and multiple brain regions within the Papez circuit. Deactivation of the Papez circuit may be a crucial neural mechanism related to cognitive deficits in patients after the rupture of ACoA aneurysm.

Investigating Recovery After Subarachnoid Hemorrhage With the Imaging, Cognition and Outcome of Neuropsychological Functioning After Subarachnoid Hemorrhage (ICONS) Study: Protocol for a Longitudinal, Prospective Cohort Study

Background

A subarachnoid hemorrhage is a hemorrhage in the subarachnoid space that is often caused by the rupture of an aneurysm. Patients who survive a subarachnoid hemorrhage have a high risk of complications and a negative long-term outcome.

Objective

The aim of the Imaging, Cognition and Outcome of Neuropsychological functioning after Subarachnoid hemorrhage (ICONS) study is to investigate whether and to what extent deficits exist in multiple domains after subarachnoid hemorrhage, including cognition, emotion and behavior, and to investigate whether brain damage can be detected in patients with subarachnoid hemorrhage. We aim to determine which early measures of cognition, emotion and behavior, and brain damage in the subacute stage play a role in long-term recovery after subarachnoid hemorrhage. Recovery is defined as functioning at a societal participation level, with a focus on resuming and maintaining work, leisure activities, and social relationships over the long term.

Methods

The ICONS study is an observational, prospective, single-center cohort study. The study includes patients with subarachnoid hemorrhage admitted to the Neurosurgery Unit of the University Medical Centre Groningen in the Netherlands. The inclusion criteria include diagnosis of an aneurysmal subarachnoid hemorrhage or an angiographically negative subarachnoid hemorrhage, sufficient ability in the Dutch language, and age older than 18 years. Patients will undergo neuropsychological assessment and magnetic resonance imaging 6 months after the subarachnoid hemorrhage. Furthermore, patients will be asked to fill in questionnaires on multiple psychosocial measures and undergo a structured interview at 6 months, 1 year, and 2 years after the subarachnoid hemorrhage. The primary outcome measure of the ICONS study is societal participation 1 year after the subarachnoid hemorrhage, measured with the Dutch version of the Impact on Participation and Autonomy questionnaire.

Results

The study was launched in December 2019 and recruitment is expected to continue until June 2023. At the time of the acceptance of this paper, 76 patients and 69 healthy controls have been included. The first results are expected in early 2023.

Conclusions

The ICONS study is the first to collect and combine data after subarachnoid hemorrhage in a variety of domains, including cognition, emotion and behavior, and brain damage. The results will contribute to a more comprehensive understanding of the consequences of both aneurysmal subarachnoid hemorrhage and angiographically negative subarachnoid hemorrhage, which may ultimately optimize timely treatment for this patient group by setting realistic and attainable goals to improve daily functioning.

Trial Registration

Netherlands Trial Register NL7803; https://trialsearch.who.int/Trial2.aspx?TrialID=NL7803

International Registered Report Identifier (IRRID)

DERR1-10.2196/38190

Aggravation of Enlarged Perivascular Spaces in the Centrum Semiovale of Patients with Aneurysmal Subarachnoid Hemorrhage

PURPOSE

This study aimed to investigate whether enlarged perivascular spaces (ePVS) within the basal ganglia (BG) or centrum semiovale (CSO) aggravate in patients with aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

We retrospectively evaluated 139 patients who had undergone brain magnetic resonance imaging (MRI) within 1 month of aSAH occurrence from January 2007 to November 2018. Follow-up brain MRI of 99 patients were available. We scored ePVS in the BG and CSO on a score of 0-4 (0 = no ePVS, 4 ≥ 40 ePVS) on initial and follow-up T2-weighted MRI. Aggravation of ePVS was defined as an ePVS score increase of ≥ 1 on follow-up MRI compared to the initial score. We compared the characteristics between patients with and without aggravation of ePVS and investigated associated variables using logistic regression.

RESULTS

Aggravation of ePVS in the CSO and BG was noted in 31 (31.3%) and 6 (6.1%) patients, respectively. After adjusting for age, sex, and the MRI follow-up period, aggravation of ePVS in the CSO was independently associated with a high Fisher grade (p = 0.007) and high burden of initial ePVS in the CSO (p = 0.049).

CONCLUSION

Aggravation of ePVS, particularly those in the CSO, had occurred in the long-term follow-up of aSAH patients. This was independently associated with a high burden of aSAH. The amount of subarachnoid blood might have aggravated the drainage of interstitial fluid through glymphatic dysfunction.

Targeting gut dysbiosis as a means to enhance recovery from surgical brain injury

Background

Surgical brain injury (SBI) impacts roughly 800,000 people who undergo neurosurgical procedures each year. SBI is the result of unavoidable parenchymal damage, vessel disruption, and thermal injury that is an inherent part of all neurosurgical procedures. Clinically, SBI has been associated with postoperative seizures and long-term neurobehavioral deficits. Current therapies are aimed at providing symptom relief by reducing swelling and preventing seizures. However, there are no therapies aimed at reducing the extent of SBI preoperatively. The microbiome-gut-brain axis may serve as a potential target for the development of new preventative therapies due to its extensive involvement in central nervous system function.

Methods

An extensive literature review was conducted to determine whether there is a potential role for dysbiosis treatment in reducing the extent of SBI.

Results

Treatment of gut dysbiosis deserves further exploration as a potential means of reducing the extent of unavoidable SBI. Dysbiosis has been correlated with increased neuroinflammation through impaired immune regulation, increased blood-brain barrier permeability, and increased production of reactive metabolites. Recently, dysbiosis has also been linked to acute neurological dysfunction in the postoperative state. Importantly, treatment of dysbiosis has been correlated with better patient outcomes and decreased length of stay in surgical patients.

Conclusion

Current literature supports the role of dysbiosis treatment in the preoperative setting as a means of optimizing neurological recovery following unavoidable SBI that results from all neurosurgical procedures.

Subarachnoid Hemorrhage is Followed by Pituitary Gland Volume Loss: A Volumetric MRI Observational Study

Background

Subarachnoid hemorrhage (SAH) is a devastating disease associated with high mortality and morbidity. Besides neurological sequelae, neuropsychological deficits largely contribute to patients’ long-term quality of life. Little is known about the pituitary gland volume (PGV) after SAH compared to healthy referents and the association of PGV with long-term outcome including cognitive function.

Methods

Sixty consecutive non-traumatic SAH patients admitted to the neurological intensive care unit between 2010 and 2014 were enrolled. 3-Tesla magnetic resonance imagining was performed at baseline (16 days) and 12 months after SAH to measure PGV semi-automatically using the software iPlan Net 3.5.0. PGV was compared to age and sex matched healthy referents. The difference between baseline and 1-year-PGV was classified as increase (> 20 mm³ PGV increase), stable (± 20 mm³), or decrease (> 20 mm³ PGV decrease). In addition, total intracerebral volume was calculated. Neuropsychological testing was applied in 43 SAH patients at 1-year follow up encompassing several domains (executive, attention, memory) and self-assessment (questionnaire for self-perceived deficits in attention [German: FEDA]) of distractibility in mental processes, fatigue and decrease in motivation. Multivariable regression with multivariable generalized linear models was used for comparison of PGVs and for subgroup analysis to evaluate a potential association between PGV and neuropsychological outcome.

Results

Patients were 53 years old (IQR = 44–63) and presented with a median Hunt&Hess grade of 2 (IQR = 1–3). SAH patients had a significantly lower PGV both at baseline (360 ± 19 mm³, p < 0.001) and 1 year (367 ± 18 mm³p < 0.001) as compared to matched referents (mean 505 ± 18 mm³). PGV decreased by 75 ± 8 mm³ in 28 patients, increased by 120 ± 22 mm³ in 22 patients and remained stable in 10 patients at 1-year follow-up. PGV in patients with PGV increase at 12 months was not different to healthy referents (p = 0.062). Low baseline PGV was associated with impaired executive functions at 1 year (adjOR = 8.81, 95%-CI = 1.46–53.10, p = 0.018) and PGV decrease within 1 year was associated with self-perceived worse motivation (FEDA; Wald-statistic = 6.6, df = 1, p = 0.010).

Conclusions

Our data indicate significantly lower PGVs following SAH. The association of sustained PGV decrease with impaired neuropsychological long-term outcome warrants further investigations including neuroendocrine hormone measurements.

Neurovascular disease, diagnosis, and therapy: Subarachnoid hemorrhage and cerebral vasospasm

The worldwide incidence of spontaneous subarachnoid hemorrhage is about 6.1 per 100,000 cases per year (Etminan et al., 2019). Eighty-five percent of cases are due to intracranial aneurysms. The mean age of those affected is 55 years, and two-thirds of the patients are female. The prognosis is related mainly to the neurologic condition after the subarachnoid hemorrhage and the age of the patient. Overall, 15% of patients die before reaching the hospital, another 20% die within 30 days, and overall 75% are dead or remain disabled. Case fatality has declined by 17% over the last 3 decades. Despite the improvement in outcome probably due to improved diagnosis, early aneurysm repair, administration of nimodipine, and advanced intensive care support, the outcome is not very good. Even among survivors, 75% have permanent cognitive deficits, mood disorders, fatigue, inability to return to work, and executive dysfunction and are often unable to return to their premorbid level of functioning. The key diagnostic test is computed tomography, and the treatments that are most strongly supported by scientific evidence are to undertake aneurysm repair in a timely fashion by endovascular coiling rather than neurosurgical clipping when feasible and to administer enteral nimodipine. The most common complications are aneurysm rebleeding, hydrocephalus, delayed cerebral ischemia, and medical complications (fever, anemia, and hyperglycemia). Management also probably is optimized by neurologic intensive care units and multidisciplinary teams.

Correlation between gray matter volume loss followed by aneurysmal subarachnoid hemorrhage and subarachnoid hemorrhage volume

PURPOSE

Aneurysmal subarachnoid hemorrhage (SAH) can chronically affect cognitive function, and SAH has been suggested to result in regional brain damage. This study aimed to assess regional structural damage according to initial clinical status including SAH volume.

METHODS

A total of 63 consecutive patients treated with coil embolization for intracranial aneurysms for more than 6 months were enrolled. Of these, 35 patients had SAH and 28 patients who were treated for unruptured aneurysms served as controls. Volumetric T1-weighted images were acquired with 1 mm isotropic voxel. The SAH volume was measured semi-automatically from the initial brain CT scan. Voxel-based group comparison was conducted to assess regional gray matter volume (GMV) changes. Voxel-based multiple regression was conducted to analyze regional GMV change and SAH volume. The clinical factors (Glasgow Coma Scale (GCS), SAH volume, systolic blood pressure, and serum laboratory findings) associated with regional GMV were also analyzed by using multiple regression.

RESULTS

The SAH group had significantly lower GMV in the left hippocampus and higher GMV in the visual cortex than controls (Alphasim-corrected p < 0.05, voxel level of p < 0.001). The GMV of the bilateral hippocampi, thalami, and left medial orbital gyrus was negatively correlated with the initial SAH volume (FDR-corrected p < 0.05). SAH volume and GCS were associated with the hippocampal GMV in multiple regression (p < 0.05).

CONCLUSIONS

Chronic regional GMV change after SAH was related to the severity of initial clinical status including SAH volume. This finding supports the pathophysiological hypothesis of SAH-induced microstructural brain injury.

Cognitive outcome after surgical clipping versus endovascular coiling in patients with subarachnoid hemorrhage due to ruptured anterior communicating artery aneurysm

Ruptured anterior communicating artery aneurysms are commonly associated with deficits in memory and executive functions. However, little studies are available on the effect of surgical clipping (SC) and endovascular coiling (EC) on cognitive functioning. This study evaluates cognitive functioning in 35 patients with subarachnoid hemorrhage after ruptured anterior communicating artery aneurysm (ACoA) compared to 20 healthy controls (HC) and assesses the effect of SC (n = 19) compared to EC (n = 16) on cognitive performances. All participants were investigated with an extensive neuropsychological test battery assessing attention, memory and visuospatial and executive functions. The strength of this study is an in-depth investigation of several cognitive domains together and several memory functions together within the auditory-verbal and visuospatial memory domain for unrelated and related information. The ACoA group was significantly more deficient in attention, auditory-verbal and visuospatial memory and executive functions compared to HCs. No significant differences were found between both groups concerning visuospatial functions. Within the patient group, the SC group, as compared to the EC group, showed a significantly worse performance for auditory-verbal and visuospatial memory. No significant differences could be detected between both groups with regard to attention and visuospatial and executive functions. In conclusion, this study provides evidence for the advantage of EC in ACoA patients over SC in terms of cognitive outcome.

Magnetic Resonance Imaging in Aneurysmal Subarachnoid Hemorrhage: Current Evidence and Future Directions

BACKGROUND

Aneurysmal subarachnoid hemorrhage (aSAH) is associated with an unacceptably high mortality and chronic disability in survivors, underscoring a need to validate new approaches for treatment and prognosis. The use of advanced imaging, magnetic resonance imaging (MRI) in particular, could help address this gap given its versatile capacity to quantitatively evaluate and map changes in brain anatomy, physiology and functional activation. Yet there is uncertainty about the real value of brain MRI in the clinical setting of aSAH.

METHODS

In this review, we discuss current and emerging MRI research in aSAH. PubMed was searched from inception to June 2017, and additional studies were then chosen on the basis of relevance to the topics covered in this review.

RESULTS

Available studies suggest that brain MRI is a feasible, safe, and valuable testing modality. MRI detects brain abnormalities associated with neurologic examination, outcomes, and aneurysm treatment and thus has the potential to increase knowledge of aSAH pathophysiology as well as to guide management and outcome prediction. Newer pulse sequences have the potential to reveal structural and physiological changes that could also improve management of aSAH.

CONCLUSION

Research is needed to confirm the value of MRI-based biomarkers in clinical practice and as endpoints in clinical trials, with the goal of improving outcome for patients with aSAH.

RECOVERY OF MEMORY AFTER CEREBRAL ARTERY ANEURYSM SURGERY

The principal study objective was to define whether memory deficits (numerical, working, verbal-mechanical, verbal-logical and visual memory) occurred in patients submitted to surgery for brain artery aneurysm and whether significant recovery of memory took place with time. The study sample included 92 patients, i.e. 35 (38%) male and 57 (62%) female patients aged 27 to 76 years. Neuropsychological testing was conducted at Zagreb University Hospital Centre, Department of Neurosurgery, from 1998 to 2012, in two time intervals: first within 11 months following surgery, and then 12 to 48 months after surgery. The obtained results showed that verbal-mechanical, verbal-logical, and visual memory deficits were present in the first testing interval. In the second testing, the verbal-logical and visual memory deficits were still present, while the tests of verbal-mechanical memory showed deficits in capacity and learning curve, but the results for short- and long-term memory were within the normal ranges. Neither the first nor the second testing showed deficits of numerical and working memory. Based on our results, we can conclude that long-term verbal-mechanical and visual short- and long-term memory had recovered to a statistically significant level, whereas other types of memory showed no significant recovery.

Hippocampus subfield volumetry after microsurgical or endovascular treatment of intracranial aneurysms-an explorative study

BACKGROUND

To study hippocampus subfield volumes in patients after microsurgical clipping (MC) and/or endovascular coiling (EC) of intracranial aneurysms.

METHODS

Hippocampus subfield volumetry was performed using FreeSurfer v6.0 in 51 patients (35 females, mean age 54.9 ± 11.9 years, range 24-78 years). Visual inspection of image and segmentation quality was performed prior to statistical analyses. Multiple regression analysis, controlled for age, sex, and side of treatment, was used to assess the impact of prior MC and history of subarachnoid haemorrhage (SAH) on hippocampus subfield volumes (cornu ammonis (CA)-2/3, CA-4, subiculum). Partial correlation analyses were used to assess effect of multiple treatments on hippocampus subfield volumes.

RESULTS

Prior MC was significantly associated with lower hippocampal subfield volumes in MC patients for right and left CA-2/3 (β = -22.32 [-40.18, -4.45]; p = 0.016 and β = -20.03 [-39.38, -0.68]; p = 0.043) and right CA-4 (β = -17.00 [-33.86, 0.12]; p = 0.048). History of SAH was not significantly associated with hippocampal subfield volumes. We observed a higher disease burden in the MC cohort. The number of aneurysms correlated with right-sided hippocampal subfield volumes while the number of treatment interventions did not.

CONCLUSION

In this explorative study, we found that history of MC was significantly associated with lower volumes in distinct hippocampal subfields, which may be a consequence of a more extensive treatment. This could indicate specific atrophy of CA-2/3 after MC and should motivate hippocampal subfield assessment in larger cohorts.

Predictors of cognitive function in the acute phase after aneurysmal subarachnoid hemorrhage

BACKGROUND

Cognitive dysfunction is the most common form of neurological impairment after aneurysmal subarachnoid hemorrhage (aSAH) in the chronic phase. Cognitive deficits in the acute phase after aSAH, however, remain scarcely investigated. The aim of the present study was to test cognitive function and to identify medical predictors of cognitive deficits in the acute phase of aSAH.

METHODS

Prospective study including 51 patients treated for aSAH. Patients were treated in accordance with a standardized institutional protocol and subjected to neuropsychological evaluation around discharge from neurosurgical care. The neuropsychological test results were transformed into a global cognitive impairment index where an index value of 0.00 is considered normal and 1.00 is considered maximally pathological. Patients with an index score of less than 0.75 were considered having good global cognitive function while those with an index score equal to or above 0.75 were considered having poor global cognitive function. Univariate and multiple regression analysis were used to identify medical predictors of cognitive function.

RESULTS

Fifty-seven percent of the patients had poor cognitive function. They showed severe cognitive deficits, with most tests falling well below two standard deviations from the expected normal mean. Poor cognitive function was not reflected in a poor modified Rankin score in almost half of the cases. Patients with good cognitive function showed only mild cognitive deficits with most tests falling only slightly below the normal mean. Delayed memory was the most affected function in both groups. Univariate analysis identified acute hydrocephalus and aSAH-acquired cerebral infarction to be predictors of poor cognitive function. Cerebrospinal fluid drainage in excess of 2000 ml six-folded the risk of poor cognitive function, whereas a new cerebral infarction 11-folded the respective risk of poor cognitive function.

CONCLUSION

More than half of aSAH patients have severe cognitive deficits in the acute phase. The modified Rankin Score should be combined with neuropsychological screening in the acute phase after aSAH to get a more accurate description of the patients' disabilities. Acute hydrocephalus and aSAH-acquired cerebral infarction are the strongest predictors of poor cognitive function in the acute phase.

Gray-to-white matter ratio predicts long-term recovery potential of patients with aneurysmal subarachnoid hemorrhage

Predicting recovery potential of patients with aneurysmal subarachnoid hemorrhage (aSAH) is challenging. We investigated whether the gray-to-white matter ratio (GWR) predicts recovery of cognitive function (CF) and quality of life (QOL) of these patients. We analyzed data of 69 patients with aSAH. Patients' demographics, comorbidities, and neurological status were recorded. One year after aSAH, Montreal Cognitive Assessment (MoCA) and Short Form-36 (SF-36) tests were administered to the patients, and brain volumes of patients were examined using MRI. Three years after aSAH, MoCA and SF-36 tests were conducted again. Differences between the test scores 1 and 3 years after aSAH were evaluated (ΔMoCA and ΔSF-36). Patients with ΔMoCA ≥ 4 points and those with ΔSF-36 ≥ 8 points were referred to as good MoCA and SF-36 recovery, respectively. ΔMoCA correlated with GWR in male and female patients (females: p < 0.001, R² = 0.581; males: p < 0.001, R² = 0.481). In female patients, GWR > 1.34 predicted good MoCA recovery with 82.3% sensitivity and 80% specificity, and in male patients, GWR > 1.36 predicted good MoCA recovery with 80% sensitivity and 95% specificity. ΔSF-36 correlated with GWR in male and female patients (females: p < 0.001, R² = 0.479; males: p < 0.001, R² = 0.627). In female patients, GWR > 1.35 predicted good SF-36 recovery with 74% sensitivity and 84% specificity, and in male patients, GWR > 1.38 predicted good SF-36 recovery with 72% sensitivity and 92% specificity. GWR is a good predictor of the recovery of CF and QOL in patients with aSAH and, thus, can help physicians to better organize rehabilitation of patients.

Cognitive Sequelae of Unruptured and Ruptured Intracranial Aneurysms and their Treatment: Modalities for Neuropsychological Assessment

BACKGROUND

Cognitive sequelae frequently follow subarachnoid hemorrhage (SAH) and include deficits across multiple domains of executive function. This factor affects overall functional outcomes negatively, especially in younger patients. Several clinical correlates predict development and severity of cognitive dysfunction after SAH. Hypothetical mechanisms of cognitive dysfunction in the absence of radiographic lesion include cerebral hypoperfusion and blood breakdown products, resulting in perturbed interneuronal communication and network synchrony, excitotoxicity, and altered microRNA expression.

METHODS

The PubMed database was searched for articles discussing cognitive outcomes in patients with unruptured and ruptured intracranial aneurysmal disease, sequelae of treatment, and modalities for neuropsychologic testing.

RESULTS

Treatment of unruptured intracranial aneurysms, although capable of preventing SAH, comes with its own set of complications and may also affect cognitive function. Neuropsychological tests such as the Montreal Cognitive Assessment, Mini-Mental Status Examination, and others have proved useful in evaluating cognitive decline. Studies using functional neurologic imaging modalities have identified regions with altered activation patterns during various cognitive tasks. The sum of research efforts in this field has provided useful insights and an initial understanding of cognitive dysfunction after aneurysm treatment and SAH that should prove useful in guiding and rendering future investigations more fruitful.

CONCLUSIONS

Development of finer and more sensitive neuropsychological tests in evaluating the different domains of cognitive function after aneurysm treatment and SAH in general will be useful in accurately determining outcomes after ictus and comparing efficacy of different therapeutic strategies.

Neurobehavioral testing in subarachnoid hemorrhage: A review of methods and current findings in rodents

The most important aspect of a preclinical study seeking to develop a novel therapy for neurological diseases is whether the therapy produces any clinically relevant functional recovery. For this purpose, neurobehavioral tests are commonly used to evaluate the neuroprotective efficacy of treatments in a wide array of cerebrovascular diseases and neurotrauma. Their use, however, has been limited in experimental subarachnoid hemorrhage studies. After several randomized, double-blinded, controlled clinical trials repeatedly failed to produce a benefit in functional outcome despite some improvement in angiographic vasospasm, more rigorous methods of neurobehavioral testing became critical to provide a more comprehensive evaluation of the functional efficacy of proposed treatments. While several subarachnoid hemorrhage studies have incorporated an array of neurobehavioral assays, a standardized methodology has not been agreed upon. Here, we review neurobehavioral tests for rodents and their potential application to subarachnoid hemorrhage studies. Developing a standardized neurobehavioral testing regimen in rodent studies of subarachnoid hemorrhage would allow for better comparison of results between laboratories and a better prediction of what interventions would produce functional benefits in humans.

Magnetic resonance imaging and brain injury in the chronic phase after aneurysmal subarachnoid hemorrhage: A systematic review

Background Case-fatality rates after aneurysmal subarachnoid hemorrhage have decreased over the past decades. However, many patients who survive an aneurysmal subarachnoid hemorrhage have long-term functional and cognitive impairments. Aims We sought to review all data on conventional brain MRI obtained in the chronic phase after aneurysmal subarachnoid hemorrhage to (1) analyze the proportion of patients with cerebral infarction or brain volume changes; (2) investigate baseline determinants predictive of MRI-detected damage; and (3) assess if brain damage is predictive of patient outcome. Summary of review All original data published between 1 January 2000 and 4 October 2017 was searched using the PUBMED, EMBASE, and Web of Science databases. Based on preset inclusion criteria, 15 from 5200 articles were included with a total of 996 aneurysmal subarachnoid hemorrhage patients. Quality assessment, risk of bias assessment, and level of evidence assessment were performed. The results according to aim, with levels of evidence, were: (1) 25 to 81% of aneurysmal subarachnoid hemorrhage patients show infarcts (strong); there is a higher ratio of cerebrospinal fluid-to-intracranial volume in patients compared to controls (strong); (2) there is a negative relation between age (moderate), DCI (low) and brain volume measurement outcomes; (3) lower brain parenchymal volume (strong) and the presence of infarcts or infarct volumes (moderate) are associated with a worse outcome. Conclusion Patients after aneurysmal subarachnoid hemorrhage may demonstrate brain infarcts and decreased brain parenchyma, which is related to worse outcome. Thereby, both brain infarcts and brain volume measurements could be used as outcome markers in pharmaceutical trials. Systematic Review Registration PROSPERO CRD42016040095.

Minimal Long-Term Neurobehavioral Impairments after Endovascular Perforation Subarachnoid Hemorrhage in Mice

Cognitive deficits are among the most severe and pervasive consequences of aneurysmal subarachnoid hemorrhage (SAH). A critical step in developing therapies targeting such outcomes is the characterization of experimentally-tractable pre-clinical models that exhibit multi-domain neurobehavioral deficits similar to those afflicting humans. We therefore searched for neurobehavioral abnormalities following endovascular perforation induction of SAH in mice, a heavily-utilized model. We instituted a functional screen to manage variability in injury severity, then assessed acute functional deficits, as well as activity, anxiety-related behavior, learning and memory, socialization, and depressive-like behavior at sub-acute and chronic time points (up to 1 month post-injury). Animals in which SAH was induced exhibited reduced acute functional capacity and reduced general activity to 1 month post-injury. Tests of anxiety-related behavior including central area time in the elevated plus maze and thigmotaxis in the open field test revealed increased anxiety-like behavior at subacute and chronic time-points, respectively. Effect sizes for subacute and chronic neurobehavioral endpoints in other domains, however, were small. In combination with persistent variability, this led to non-significant effects of injury on all remaining neurobehavioral outcomes. These results suggest that, with the exception of anxiety-related behavior, alternate mouse models are required to effectively analyze cognitive outcomes after SAH.

Ruptured carotid-ophthalmic aneurysm treatment: a non-inferiority meta-analysis comparing endovascular coiling and surgical clipping

INTRODUCTION

Aneurysms of the carotid-ophthalmic segment are relatively rare, comprising only five percent of all intracranial aneurysms. There is no consensus regarding the optimal management for ruptured carotid-ophthalmic aneurysms, whether endovascular coiling or surgical clipping provide the most favourable patient outcome. The aim of this meta-analysis is to analyse these two treatment modalities for ruptured carotid-ophthalmic aneurysms with respect to independent clinical outcome.

METHODS

We performed a systematic literature search in PubMed, Cochrane Central Registry of Controlled Trials and Clinicaltrials.gov for treatment of ruptured carotid-ophthalmic aneurysms, comparing endovascular coiling and surgical clipping. Primary outcome in the study was independent clinical patient outcome at follow up (defined as Glasgow Outcome Scale four-five). Secondary outcomes were poor clinical patient outcome, mortality and total angiographic occlusion. The meta-analysis was performed using the Mantel-Haenszel method for dichotomous outcome.

RESULTS

Four studies met the inclusion criteria and were included in the meta-analysis. In total, 152 patients were included. Sixty-seven of these patients were treated with endovascular coiling and 85 patients were treated with microsurgical clipping. The proportion of patients with an independent clinical outcome after coiling and clipping was comparable, OR 1.04 (95% CI: 0.40, 2.71). The proportion of patients with an independent outcome in the endovascular group was 76% and in the surgical group 71%. Mortality between the two treatment arms was equal.

CONCLUSION

Clinical outcome after endovascular coiling and surgical clipping for ruptured carotid-ophthalmic aneurysms was comparable between surgical clipping and endovascular coiling. There was no proven difference in clinical outcome after endovascular coiling and surgical clipping for ruptured carotid-ophthalmic aneurysms but the evidence was based on few studies of moderate to low quality and we cannot rule out the possibility of a difference in clinical outcome between the two treatment modalities.

Longitudinal profile of iron accumulation in good-grade subarachnoid hemorrhage

OBJECTIVE

MRI parameters of iron concentration (R2*, transverse relaxation rate), microstructural integrity (mean diffusivity and fractional anisotropy), as well as gray and white matter volumes were analyzed in patients with subarachnoid hemorrhage (SAH) and uncomplicated clinical course to detect the evolution of brain tissue changes 3 weeks and 12 months after ictus.

METHODS

MRI scans of 14 SAH patients (aneurysm of the anterior communicating artery, n = 5; no aneurysm n = 9) were compared with 14 age-matched healthy control subjects. Statistical parametric mapping (SPM) was applied to objectively identify focal changes of MRI parameters throughout the entire brain and to correlate image parameters with neuropsychological measures.

RESULTS

SPM localized significant bilateral increases in R2* signal within the white matter compartment of the temporal and parietal lobe and the cingulate gyrus (P < 0.001) which did not change significantly at 12 months. Significant gray matter volume reduction of the left insula and superior temporal gyrus (P < 0.001), as well as decreases in fractional anisotropy of the cingulate gyrus (P < 0.01) were also evident at 12 months. Significant correlations were found between fractional anisotropy signal alterations adjacent to the left middle and superior frontal gyrus and cognitive parameters of executive dysfunction (P < 0.001).

INTERPRETATION

The study indicates that iron is trapped predominantly throughout large portions of the white matter compartment in SAH patients at 12 months postbleeding. Increased disintegration of fiber tracts colocalizing with iron overload and correlating with lower executive function performance suggests that the white matter compartment is primarily susceptible toward long-term damage in patients with good clinical grade SAH.

Increased Frontal Lobe Activation After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Neurocognitive deficits are common among survivors of aneurysmal subarachnoid hemorrhage, even among those with good outcomes and no structural lesions. This study aims to probe the neurophysiological underpinnings of cognitive dysfunction among patients with ruptured intracranial aneurysms using magnetoencephalography (MEG).

METHODS

Thirteen patients who had undergone uncomplicated coiling for aneurysmal subarachnoid hemorrhage and 13 matched controls were enrolled. Neuropsychological tests were done before magnetoencephalography scans. Magnetoencephalography data were acquired in a 151-channel, whole-head magnetoencephalography system for resting state and 2 cognitive tasks (go-no-go and set-shifting). Mean time from treatment to test was 18.8 months.

RESULTS

Cognitive tasks of inhibition (go-no-go) indicated greater activation in the right anterior cingulate and inferior frontal gyrus, and cognitive set-shifting tasks (mental flexibility) indicated greater activity in the bilateral anterior cingulate cortex and right medial frontal gyrus among aneurysmal subarachnoid hemorrhage patients, with significantly different timing of activation between groups. Resting-state, beta-band connectivity of the anterior cingulate correlated negatively with Montreal Cognitive Assessment scores (left: r=-0.56; P<0.01 and right: r=-0.55; P<0.01): higher connectivity of this region was linked to poorer cognitive test performance.

CONCLUSIONS

We have shown increased activation in areas of the anterior cingulate gyrus and frontobasal regions during the execution of more demanding tasks in good grade. The degree of activation in the anterior cingulate gyrus has a negative correlation with cognitive (Montreal Cognitive Assessment) scores. These subtle differences may be related to the common neurocognitive and behavioral complaints seen in this patient population.

Novel Treatments in Neuroprotection for Aneurysmal Subarachnoid Hemorrhage

OPINION STATEMENT

New neuroprotective treatments aimed at preventing or minimizing "delayed brain injury" are attractive areas of investigation and hold the potential to have substantial beneficial effects on aneurysmal subarachnoid hemorrhage (aSAH) survivors. The underlying mechanisms for this "delayed brain injury" are multi-factorial and not fully understood. The most ideal treatment strategies would have the potential for a pleotropic effect positively modulating multiple implicated pathophysiological mechanisms at once. My personal management (RFJ) of patients with aneurysmal subarachnoid hemorrhage closely follows those treatment recommendations contained in modern published guidelines. However, over the last 5 years, I have also utilized a novel treatment strategy, originally developed at the University of Maryland, which consists of a 14-day continuous low-dose intravenous heparin infusion (LDIVH) beginning 12 h after securing the ruptured aneurysm. In addition to its well-known anti-coagulant properties, unfractionated heparin has potent anti-inflammatory effects and through multiple mechanisms may favorably modulate the neurotoxic and neuroinflammatory processes prominent in aneurysmal subarachnoid hemorrhage. In my personal series of patients treated with LDIVH, I have found significant preservation of neurocognitive function as measured by the Montreal Cognitive Assessment (MoCA) compared to a control cohort of my patients treated without LDIVH (RFJ unpublished data presented at the 2015 AHA/ASA International Stroke Conference symposium on neuroinflammation in aSAH and in abstract format at the 2015 AANS/CNS Joint Cerebrovascular Section Annual Meeting). It is important for academic physicians involved in the management of these complex patients to continue to explore new treatment options that may be protective against the potentially devastating "delayed brain injury" following cerebral aneurysm rupture. Several of the treatment options included in this review show promise and could be carefully adopted as the level of evidence for each improves. Other proposed neuroprotective treatments like statins and magnesium sulfate were previously thought to be very promising and to varying degrees were adopted at numerous institutions based on somewhat limited human evidence. Recent clinical trials and meta-analysis have shown no benefit for these treatments, and I currently no longer utilize either treatment as prophylaxis in my practice.

Microglia inflict delayed brain injury after subarachnoid hemorrhage

Inflammatory changes have been postulated to contribute to secondary brain injury after aneurysmal subarachnoid hemorrhage (SAH). In human specimens after SAH as well as in experimental SAH using mice, we show an intracerebral accumulation of inflammatory cells between days 4 and 28 after the bleeding. Using bone marrow chimeric mice allowing tracing of all peripherally derived immune cells, we confirm a truly CNS-intrinsic, microglial origin of these immune cells, exhibiting an inflammatory state, and rule out invasion of myeloid cells from the periphery into the brain. Furthermore, we detect secondary neuro-axonal injury throughout the time course of SAH. Since neuronal cell death and microglia accumulation follow a similar time course, we addressed whether the occurrence of activated microglia and neuro-axonal injury upon SAH are causally linked by depleting microglia in vivo. Given that the amount of neuronal cell death was significantly reduced after microglia depletion, we conclude that microglia accumulation inflicts secondary brain injury after SAH.

Experimental subarachnoid haemorrhage results in multifocal axonal injury

The great majority of acute brain injury results from trauma or from disorders of the cerebrovasculature, i.e. ischaemic stroke or haemorrhage. These injuries are characterized by an initial insult that triggers a cascade of injurious cellular processes. The nature of these processes in spontaneous intracranial haemorrhage is poorly understood. Subarachnoid haemorrhage, a particularly deadly form of intracranial haemorrhage, shares key pathophysiological features with traumatic brain injury including exposure to a sudden pressure pulse. Here we provide evidence that axonal injury, a signature characteristic of traumatic brain injury, is also a prominent feature of experimental subarachnoid haemorrhage. Using histological markers of membrane disruption and cytoskeletal injury validated in analyses of traumatic brain injury, we show that axonal injury also occurs following subarachnoid haemorrhage in an animal model. Consistent with the higher prevalence of global as opposed to focal deficits after subarachnoid haemorrhage and traumatic brain injury in humans, axonal injury in this model is observed in a multifocal pattern not limited to the immediate vicinity of the ruptured artery. Ultrastructural analysis further reveals characteristic axonal membrane and cytoskeletal changes similar to those associated with traumatic axonal injury. Diffusion tensor imaging, a translational imaging technique previously validated in traumatic axonal injury, from these same specimens demonstrates decrements in anisotropy that correlate with histological axonal injury and functional outcomes. These radiological indicators identify a fibre orientation-dependent gradient of axonal injury consistent with a barotraumatic mechanism. Although traumatic and haemorrhagic acute brain injury are generally considered separately, these data suggest that a signature pathology of traumatic brain injury-axonal injury-is also a functionally significant feature of subarachnoid haemorrhage, raising the prospect of common diagnostic, prognostic, and therapeutic approaches to these conditions.

Methemoglobin is an endogenous toll-like receptor 4 ligand-relevance to subarachnoid hemorrhage

Neuroinflammation is a well-recognized consequence of subarachnoid hemorrhage (SAH), and may be responsible for important complications of SAH. Signaling by Toll-like receptor 4 (TLR4)-mediated nuclear factor κB (NFκB) in microglia plays a critical role in neuronal damage after SAH. Three molecules derived from erythrocyte breakdown have been postulated to be endogenous TLR4 ligands: methemoglobin (metHgb), heme and hemin. However, poor water solubility of heme and hemin, and lipopolysaccharide (LPS) contamination have confounded our understanding of these molecules as endogenous TLR4 ligands. We used a 5-step process to obtain highly purified LPS-free metHgb, as confirmed by Fourier Transform Ion Cyclotron Resonance mass spectrometry and by the Limulus amebocyte lysate assay. Using this preparation, we show that metHgb is a TLR4 ligand at physiologically relevant concentrations. metHgb caused time- and dose-dependent secretion of the proinflammatory cytokine, tumor necrosis factor α (TNFα), from microglial and macrophage cell lines, with secretion inhibited by siRNA directed against TLR4, by the TLR4-specific inhibitors, Rs-LPS and TAK-242, and by anti-CD14 antibodies. Injection of purified LPS-free metHgb into the rat subarachnoid space induced microglial activation and TNFα upregulation. Together, our findings support the hypothesis that, following SAH, metHgb in the subarachnoid space can promote widespread TLR4-mediated neuroinflammation.

Mouse cerebral magnetic resonance imaging fails to visualize brain volume changes after experimental subarachnoid hemorrhage

BACKGROUND

Brain atrophy after subarachnoid hemorrhage (SAH) has been detected in humans and might serve as a functional read-out parameter for neuropsychological deficits. To determine whether serial magnetic resonance imaging (MRI) can provide information on brain atrophy in animals as well, mice that had undergone experimental SAH were scanned repeatedly after the bleeding.

METHODS

Using a 7-T rodent MRI, six mice were evaluated for total hemispheric, cerebrospinal fluid (CSF) and hippocampal volumes on days 1, 2, 4, 21, 28, 42 and 60 after experimental SAH or sham operation, respectively.

RESULTS

Repeated MRI scanning demonstrated a very high reproducibility with minimum standard deviation. Nevertheless, no significant differences were found between the two groups concerning hemispherical volumes or hippocampal volumes. A transient but significant increase in CSF volume was detected on days 2 and 60 after SAH. Compared with the existing method, no MRI data on brain atrophy in mice after experimental SAH have been published.

CONCLUSION

Repeated brain MRI in mice after experimental SAH did not provide additional information on brain atrophy. Our data suggest that this is not due to a lack of sensitivity of the method. Despite all promising details about MRI, our results should initiate careful consideration (additional sequences/other questions) before its further use in this certain area, especially since it is expensive and associated with demanding logistics.

Cerebral tau is elevated after aneurysmal subarachnoid haemorrhage and associated with brain metabolic distress and poor functional and cognitive long-term outcome

BACKGROUND

Recent evidence suggests axonal injury after aneurysmal subarachnoid haemorrhage (aSAH). The microtubule-associated protein, tau, has been shown to be elevated in the cerebrospinal fluid after aSAH, however, brain extracellular tau levels and their relation to long-term neurological and cognitive outcomes have not been investigated.

METHODS

Serial cerebral microdialysis (CMD) samples were collected from 22 consecutive aSAH patients with multimodal neuromonitoring to determine CMD-total-tau by ELISA. CMD-total-tau was analysed considering other brain metabolic parameters, brain tissue oxygen tension (PbtO2), and functional and neuropsychological outcome at 12 months. All outcome models were analysed using generalised estimating equations with an autoregressive working correlation matrix to account for multiple measurements of brain extracellular proteins per subject.

RESULTS

CMD-total-tau levels positively correlated with brain extracellular fluid levels of lactate (r=0.40, p<0.001), glutamate (r=0.45, p<0.001), pyruvate (r=0.26, p<0.001), and the lactate-pyruvate ratio (r=0.26, p<0.001), and were higher in episodes of hypoxic (PbtO2<20 mm Hg) brain extracellular lactate elevation (>4 mmol/L) (p<0.01). More importantly, high CMD-total-tau levels were associated with poor functional outcome (modified Rankin Scale ≥4) 12 months after aSAH even after adjusting for disease severity and age (p=0.001). A similar association was found with 3/5 neuropsychological tests indicative of impairments in cognition, psychomotor speed, visual conceptualisation and frontal executive functions at 1 year after aSAH (p<0.01).

CONCLUSIONS

These results suggest that CMD-total tau may be an important biomarker for predicting long-term outcome in patients with severe aSAH. The value of axonal injury needs further confirmation in a larger patient cohort, preferably combined with advanced imaging techniques.

Aneurysmal subarachnoid haemorrhage from a neuroimaging perspective

Neuroimaging is a key element in the management of patients suffering from subarachnoid haemorrhage (SAH). In this article, we review the current literature to provide a summary of the existing neuroimaging methods available in clinical practice. Noncontrast computed tomography is highly sensitive in detecting subarachnoid blood, especially within 6 hours of haemorrhage. However, lumbar puncture should follow a negative noncontrast computed tomography scan in patients with symptoms suspicious of SAH. Computed tomography angiography is slowly replacing digital subtraction angiography as the first-line technique for the diagnosis and treatment planning of cerebral aneurysms, but digital subtraction angiography is still required in patients with diffuse SAH and negative initial computed tomography angiography. Delayed cerebral ischaemia is a common and serious complication after SAH. The modern concept of delayed cerebral ischaemia monitoring is shifting from modalities that measure vessel diameter to techniques focusing on brain perfusion. Lastly, evolving modalities applied to assess cerebral physiological, functional and cognitive sequelae after SAH, such as functional magnetic resonance imaging or positron emission tomography, are discussed. These new techniques may have the advantage over structural modalities due to their ability to assess brain physiology and function in real time. However, their use remains mainly experimental and the literature supporting their practice is still scarce.

The role of the microcirculation in delayed cerebral ischemia and chronic degenerative changes after subarachnoid hemorrhage

The mortality after aneurysmal subarachnoid hemorrhage (SAH) is 50%, and most survivors suffer severe functional and cognitive deficits. Half of SAH patients deteriorate 5 to 14 days after the initial bleeding, so-called delayed cerebral ischemia (DCI). Although often attributed to vasospasms, DCI may develop in the absence of angiographic vasospasms, and therapeutic reversal of angiographic vasospasms fails to improve patient outcome. The etiology of chronic neurodegenerative changes after SAH remains poorly understood. Brain oxygenation depends on both cerebral blood flow (CBF) and its microscopic distribution, the so-called capillary transit time heterogeneity (CTH). In theory, increased CTH can therefore lead to tissue hypoxia in the absence of severe CBF reductions, whereas reductions in CBF, paradoxically, improve brain oxygenation if CTH is critically elevated. We review potential sources of elevated CTH after SAH. Pericyte constrictions in relation to the initial ischemic episode and subsequent oxidative stress, nitric oxide depletion during the pericapillary clearance of oxyhemoglobin, vasogenic edema, leukocytosis, and astrocytic endfeet swelling are identified as potential sources of elevated CTH, and hence of metabolic derangement, after SAH. Irreversible changes in capillary morphology and function are predicted to contribute to long-term relative tissue hypoxia, inflammation, and neurodegeneration. We discuss diagnostic and therapeutic implications of these predictions.

FMRI of working memory impairment after recovery from subarachnoid hemorrhage

Recovery from aneurysmal subarachnoid hemorrhage (SAH) is often incomplete and accompanied by subtle but persistent cognitive deficits. Previous neuropsychological reports indicate these deficits include most prominently memory impairment, with working memory particularly affected. The neural basis of these memory deficits remains unknown and unexplored by functional magnetic resonance imaging (fMRI). In the present study, patients who experienced (SAH) underwent fMRI during the performance of a verbal working memory paradigm. Behavioral results indicated a subtle but statistically significant impairment relative to healthy subjects in working memory performance accuracy, which was accompanied by relatively increased blood-oxygen level dependent signal in widespread left and right hemisphere cortical areas during periods of encoding, maintenance, and retrieval. Activity increases remained after factoring out inter-individual differences in age and task performance, and included most notably left hemisphere regions associated with phonological loop processing, bilateral sensorimotor regions, and right hemisphere dorsolateral prefrontal cortex. We conclude that deficits in verbal working memory following recovery from (SAH) are accompanied by widespread differences in hemodynamic correlates of neural activity. These differences are discussed with respect to the immediate and delayed focal and global brain damage that can occur following (SAH), and the possibility that this damage induces subcortical disconnection and subsequent decreased efficiency in neural processing.

Early MoCA-assessed cognitive impairment after aneurysmal subarachnoid hemorrhage and relationship to 1-year functional outcome

Recent clinical research into aneurysmal subarachnoid hemorrhage (aSAH) has confirmed the long-term effect of cognitive dysfunction on functional outcomes. We hypothesized that early cognitive impairment was a marker of permanent brain injury and hence predicted long-term functional outcome. Hong Kong Chinese patients with aneurysmal subarachnoid hemorrhage were evaluated prospectively by means of the Montreal Cognitive Assessment (MoCA) in the subacute phase (2-4 weeks after aSAH) and by neuropsychological evaluation of functional outcomes in the chronic phase (1 year after aSAH). This multi-center prospective observational study is registered at ClinicalTrials.gov of the US National Institutes of Health (NCT01038193). One hundred and eight patients completed both the subacute and chronic phase assessments. Cognitive dysfunction in the subacute phase independently correlated with functional outcomes at 1 year, after adjusting for age, admission clinical condition, treatment modality, motor score, and mobility in the subacute phase, but the positive predictive values remained low. MoCA-assessed cognitive impairment in the subacute phase cannot accurately predict functional outcomes at 1 year. Future study should focus on understanding the relative importance of different components of early cognitive impairment.

Impact of global cerebral atrophy on clinical outcome after subarachnoid hemorrhage

OBJECT

Atrophy in specific brain areas correlates with poor neuropsychological outcome after subarachnoid hemorrhage (SAH). Few studies have compared global atrophy in SAH with outcome. The authors examined the relationship between global brain atrophy, clinical factors, and outcome after SAH.

METHODS

This study was a post hoc exploratory analysis of the Clazosentan to Overcome Neurological Ischemia and Infarction Occurring After Subarachnoid Hemorrhage (CONSCIOUS-1) trial, a randomized, double-blind, placebo-controlled trial of 413 patients with aneurysmal SAH. Patients with infarctions or areas of encephalomalacia on CT, and those with large clip/coil artifacts, were excluded. The 97 remaining patients underwent CT at baseline and 6 weeks, which was analyzed using voxel-based volumetric measurements. The percentage difference in volume between time points was compared against clinical variables. The relationship with clinical outcome was modeled using univariate and multivariate analysis.

RESULTS

Older age, male sex, and systemic inflammatory response syndrome (SIRS) during intensive care stay were significantly associated with brain atrophy. Greater brain atrophy was significantly associated with poor outcome on the modified Rankin scale (mRS), severity of deficits on the National Institutes of Health Stroke Scale (NIHSS), worse executive functioning, and lower EuroQol Group-5D (EQ-5D) score. Adjusted for confounders, brain atrophy was not significantly associated with Mini-Mental State Examination and Functional Status Examination scores. Brain atrophy was not associated with angiographic vasospasm or delayed ischemic neurological deficit.

CONCLUSIONS

Worse mRS score, NIHSS score, executive functioning, and EQ-5D scores were associated with greater brain atrophy and older age, male sex, and SIRS burden. These data suggest outcome is associated with factors that cause global brain injury independent of focal brain injury.

SAHIT Investigators--on the outcome of some subarachnoid hemorrhage clinical trials

Outcome of patients with aneurysmal subarachnoid hemorrhage (SAH) has improved over the last decades. Yet, case fatality remains nearly 40% and survivors often have permanent neurological, cognitive and/or behavioural sequelae. Other than nimodipine drug or clinical trials have not consistently improved outcome. We formed a collaboration of SAH investigators to create a resource for prognostic analysis and for studies aimed at optimizing the design and analysis of phase 3 trials in aneurysmal SAH. We identified investigators with data from randomized, clinical trials of patients with aneurysmal SAH or prospectively collected single- or multicentre databases of aneurysmal SAH patients. Data are being collected and proposals to use the data and to design future phase 3 clinical trials are being discussed. This paper reviews some issues discussed at the first meeting of the SAH international trialists (SAHIT) repository meeting. Investigators contributed or have agreed to contribute data from several phase 3 trials including the tirilazad trials, intraoperative hypothermia for aneurysmal SAH trial, nicardipine clinical trials, international subarachnoid aneurysm trial, intravenous magnesium sulphate for aneurysmal SAH, magnesium for aneurysmal SAH and from prospectively-collected data from four institutions. The number of patients should reach 15,000. Some industry investigators refused to provide data and others reported that their institutional research ethics boards would not permit even deidentified or anonymized data to be included. Others reported conflict of interest that prevented them from submitting data. The problems with merging data were related to lack of common definitions and coding of variables, differences in outcome scales used, and times of assessment. Some questions for investigation that arose are discussed. SAHIT demonstrates the possibility of SAH investigators to contribute data for collaborative research. The problems are similar to those already documented in other similar collaborative efforts such as in head injury research. We encourage clinical trial and registry investigators to contact us and participate in SAHIT. Key issues moving forward will be to use common definitions (common data elements), outcomes analysis, and to prioritize research questions, among others.

Global cerebral atrophy after subarachnoid hemorrhage: a possible marker of acute brain injury and assessment of its impact on outcome

There is a correlation between poor neuropsychological outcome and focal regions of atrophy in patients with subarachnoid hemorrhage (SAH). No study has investigated the impact of global brain atrophy on outcome after SAH. In other neurological disorders, such as multiple sclerosis, a correlation has been found between global atrophy and outcome. This analysis of patients entered into a randomized clinical trial of clazosentan in patients with SAH (CONSCIOUS-1) investigated the relationship between global cerebral atrophy, clinical factors, and outcome.The 413 patients in the CONSCIOUS-1 study underwent cranial computed tomography (CT) on admission and 6 weeks after SAH. After patients with large clip/coil artefacts and those with infarctions on CT were excluded, 97 patients remained and had voxel-based volumetric measurements of the baseline and 6-week CT scans. The percentage difference in volume between times was taken and analysed against clinical variables. Relationships were modeled using univariate and multivariate analysis.Age, female gender, and higher body temperature during the patient's stay in the intensive care unit were significantly correlated with brain atrophy. Greater brain atrophy significantly correlated with poor outcome (modified Rankin scale), more severe neurological deficits on the National Institute of Health Stroke Scale (NIHSS), and poorer health status (EQ-5D).

Quantification of cerebral volumes on MRI 6 months after aneurysmal subarachnoid hemorrhage

BACKGROUND AND PURPOSE

MRI can be used to assess structural damage to the brain after aneurysmal subarachnoid hemorrhage. We tuned, validated, and applied k-Nearest Neighbor-based segmentation to quantify cerebral volumes on MRI 6 months after aneurysmal subarachnoid hemorrhage.

METHODS

After tuning, the accuracy of k-Nearest Neighbor-based segmentation was assessed with manual segmentations. Next, supratentorial cerebral parenchymal, peripheral cerebrospinal fluid, and lateral ventricular volumes of 55 patients were compared with those of 25 age- and sex-matched control subjects and related to clinical outcome (modified Rankin Scale).

RESULTS

k-Nearest Neighbor-based segmentation showed good agreement with manual segmentations. Compared with control subjects, patients had a larger lateral ventricular volume (difference: log-transformed values 0.54; 95% CI,0.33-0.75), smaller peripheral cerebrospinal fluid volume (-26 mL; 95% CI, -40 to -11), and similar cerebral parenchymal volume (2 mL; 95% CI, -10 to 15). In patients, parenchymal (median split; OR, 38.8; 95% CI, 4.6-329.0) and ventricular volumes (7.4; 95% CI, 1.6-33.5) correlated with functional outcome.

CONCLUSIONS

k-Nearest Neighbor-based segmentation provides accurate cerebral volume measurements after aneurysmal subarachnoid hemorrhage. In this proof-of-principle study of this volumetric technique, we demonstrated volume changes relative to controls, which correlated with functional outcome.

Prevalence, timing, risk factors, and mechanisms of anterior cerebral artery infarctions following subarachnoid hemorrhage

Anterior cerebral artery (ACA) ischemia may be underdiagnosed following subarachnoid hemorrhage (SAH). The purpose of this study is to characterize the prevalence, timing, and risk factors for ACA infarction, following primary spontaneous SAH. This was a retrospective study of consecutive SAH patients. Final admission CT scans were reviewed for the presence of ACA infarction, and prior scans serially reviewed to determine timing of infarct. Infarctions were categorized as any, early (days 0-3), late (days 4-15), or perioperative (2 days after aneurysm treatment). Demographic and clinical variables were statistically interrogated to identify predictors of infarct types. Of the 474 study patients, ACA infarctions occurred in 8 % of patients, with 42 % occurring during the early period. Multivariate logistic regression identified H/H grade 4/5 (p < 0.001), ACA/ACom aneurysm location (p < 0.001), and surgical clipping (p = 0.011) as independent predictors of any ACA infarct. In Cox hazards analysis, H/H grade 4/5 (p < 0.001), CT score 3/4 (p = 0.042), ACA/ACom aneurysm location (p < 0.001), and surgical clipping (p = 0.012) independently predicted any ACA infarct. Bivariate logistic regression identified non-Caucasian race (p = 0.032), H/H grade 3/4 (p < 0.001), CT score 3/4 (p = 0.006), IVH (p = 0.027), and ACA/ACom aneurysm (p = 0.001) as predictors of early infarct (EI). Late infarct (LI) was predicted by H/H grade 4/5 (p = 0.040), ACA/ACom aneurysm (p < 0.001), and vasospasm (p = 0.027), while postoperative infarct (PI) was predicted by surgical clipping (p = 0.044). Log-rank analyses confirmed non-Caucasian race (p = 0.024), H/H grade 3/4 (p < 0.001), CT score 3/4 (p = 0.003), IVH (p = 0.010), and ACA/ACom aneurysm (p < 0.001) as predictors of EI. LI was predicted by ACA/ACom aneurysm (p < 0.001) while surgical clipping (p = 0.046) again predicted PI. Clinical severity/grade and ACA/ACom aneurysm location are the most consistent predictors of ACA infarctions. Vasospastic and non-vasospastic processes may concurrently contribute to ACA infarcts.

Persistent region-dependent neuroinflammation, NMDA receptor loss and atrophy in an animal model of penetrating brain injury

Dynamic changes in neuroinflammation and glutamate NMDA receptors (NMDAR) have been noted in traumatic and ischemic brain injury.

AIM

Here we investigate the time course and regional distribution of these changes and their relationship with atrophy in a rat model of penetrating brain injury.

MATERIALS METHODS

Quantitative autoradiography, with the neuroinflammation marker [³H]PK11195 and the NMDAR antagonist [¹²⁵I]iodoMK801, was performed on brains of animals subjected to a unilateral wireknife injury at the level of striatum and killed 3 - 60 days later. Regional atrophy was measured by morphometry.

RESULTS

The injury produced large increases in [³H]PK11195 binding density in cortical and septal regions adjacent to the knife track by day 7, with modest increases in the striatum. [¹²⁵I]iodoMK801 binding was reduced in cor tical and hippocampal regions showing marked neuroinflammation, which showed marked atrophy at subsequent time points.

CONCLUSION

These results indicate that neuroinflammaton and loss of NMDAR precede and predict tissue atrophy in cortical and hippocampal regions.

Artifact quantification and tractography from 3T MRI after placement of aneurysm clips in subarachnoid hemorrhage patients

Background

The application of advanced 3T MRI imaging techniques to study recovery after subarachnoid hemorrhage (SAH) is complicated by the presence of image artifacts produced by implanted aneurysm clips. To characterize the effect of these artifacts on image quality, we sought to: 1) quantify extent of image artifact in SAH patients with implanted aneurysm clips across a range of MR sequences typically used in studies of volumetry, blood oxygen level dependent signal change (BOLD-fMRI), and diffusion-weighted imaging (DW-MRI) and 2) to explore the ability to reconstruct white matter pathways in these patients.

Methods

T1- and T2-weighted structural, BOLD-fMRI, and DW-MRI scans were acquired at 3T in two patients with titanium alloy clips in ACOM and left ACA respectively. Intensity-based planimetric contouring was performed on aligned image volumes to define each artifact. Artifact volumes were quantified by artifact/clip length and artifact/brain volume ratios and analyzed by two-way (scan-by-rater) ANOVAs. Tractography pathways were reconstructed from DW-MRI at varying distances from the artifacts using deterministic methods.

Results

Artifact volume varied by MR sequence for length (p = 0.007) and volume (p < 0.001) ratios: it was smallest for structural images, larger for DW-MRI acquisitions, and largest on fMRI images. Inter-rater reliability was high (r = 0.9626, p < 0.0001), and reconstruction of white matter connectivity characteristics increased with distance from the artifact border. In both patients, reconstructed white matter pathways of the uncinate fasciculus and inferior fronto-occipital fasciculus were clearly visible within 2 mm of the artifact border.

Conclusions

Advanced 3T MR can successfully image brain tissue around implanted titanium aneurysm clips at different spatial ranges depending on sequence type. White matter pathways near clip artifacts can be reconstructed and visualized. These findings provide a reference for designing functional and structural neuroimaging studies of recovery in aSAH patients after clip placement.

Natural history and medical treatment of cognitive dysfunction after spontaneous subarachnoid haemorrhage: review of current literature with respect to aneurysm treatment

Aneurysmal subarachnoid haemorrhage (aSAH) has the highest mortality and morbidity among all types of stroke. Unfortunately, cognitive dysfunction remains a major problem to those who survive the acute crisis. Most studies focused on patients after microsurgical clipping, which turned out to be different from the modern patient cohorts. With the widespread introduction of endovascular surgery as the first choice of treatment, there was a hope that post-aSAH cognitive dysfunction could be markedly reduced. However, data showed that post-aSAH cognitive dysfunction remained a major burden to the survivors of our modern patient cohort that returned to the community more than nine months after the initial haemorrhage. There is, therefore, a need to further understand its pathophysiology and natural history, and to develop effective treatment strategy. The results are encouraging and further clinical studies are indicated. Collaborations between cognitive scientists, neurologists and neurosurgeons are essential to advance the understanding of the problem.