Sensitivity of computed tomography performed within six hours of onset of headache for diagnosis of subarachnoid haemorrhage: prospective cohort study

Vein of Galen aneurysmal malformation associated with brain abscess: A computed tomography case report

Vein of Galen malformation (VGM) is a rare congenital, uncommon intracerebral vascular anomaly rarely complicated with the development of brain abscess as secondary to primary infection or after endovascular treatment. We report a very rare finding of a vein of Galen aneurysm associated with a large brain abscess at the time of diagnosis. A 12-year-old boy with a high-grade fever, severe headache, and recurrent episodes of convulsions came into the radiology department of Kassala Advanced Diagnostic Center. On a Siemens 16-slice scanner, brain non-contrast enhanced computed tomography (NECT) and contrast enhanced CT (CECT) was used to determine the source of the acute headache and convulsions which revealed a right frontal peripherally enhancing cystic lesion measuring 5.7 × 4.7 × 5.3 cm2 surrounded by massive vasogenic edema causing mass effect with midline shift to the left side by 1.5 cm suggestive of brain abscess. There is evidence of another avidly enhancing lesion seen within the third ventricle continuous with a straight sinus surrounded by extensive vascular loops consistent with an aneurysm of the vein of Galen, it was causing compression of the cerebral aqueduct with upstream mild hydrocephalus with dilated both lateral ventricles. Late presentation, diagnosis, and treatment also lead to an increase in the morbidities and mortalities of such case conditions. Urgent intervention should be considered for better outcomes.

Comparative diagnostic efficacy of cranial CT, CTA, and DSA in subarachnoid hemorrhage management: A systematic review and meta-analysis

INTRODUCTION

Subarachnoid hemorrhage (SAH) is a critical medical condition associated with high morbidity and mortality rates. Timely and accurate diagnosis is crucial for optimal patient outcomes. Cranial computed tomography (CT), computed tomography angiography (CTA), and digital subtraction angiography (DSA) are commonly used imaging modalities for diagnosing SAH, but their comparative diagnostic efficacy remains debated.

METHODS

A systematic review and meta-analysis was conducted to evaluate the diagnostic performance of cranial CT, CTA, and DSA in identifying SAH. PubMed, Google scholar, Cochrane Library databases were searched for relevant studies published up to January 2024. Pooled sensitivity, specificity, and the summary receiver operating characteristic (SROC) curve were calculated using Review Manager 5.4.

RESULTS

A total of 31 studies involving 10,287 patients were included in the analysis. The pooled sensitivity of cranial CT for detecting SAH was 94.7 % (95 % Confidence Interval, CI) with a specificity of 98.3 % (95 % CI). CTA demonstrated a pooled sensitivity of 94.1 % (95 % CI) and specificity of 93.4 % (95 % CI). DSA showed a pooled sensitivity of 87.7 % (95 % CI) and specificity of 95.8 % (95 % CI). The SROC curve demonstrated discriminatory ability for all modalities.

CONCLUSION

Cranial CT, CTA, and DSA are valuable imaging modalities for diagnosing SAH, with high sensitivity and specificity. Cranial CT serves as an initial screening tool, while CTA offers superior sensitivity in detecting aneurysmal SAH. DSA remains essential in specific clinical scenarios. Further prospective studies are needed to validate these findings and refine diagnostic guidelines for SAH.

Shifts in Diagnostic Testing for Headache in the Emergency Department, 2015 to 2021

Importance

Subarachnoid hemorrhage is typically diagnosed by noncontrast head computed tomography (CT); lumbar puncture is recommended if computed tomography is nondiagnostic, although CT cerebral angiography has been promoted as an alternative to lumbar puncture in this diagnostic pathway. The outcomes of this debate in practice have not been studied.

Objective

To determine whether CT cerebral angiography use has increased in lieu of lumbar puncture among emergency department (ED) patients with headache, with an increase in unruptured intracranial aneurysm detection.

Design, Setting, and Participants

This retrospective cohort study took place in 21 community EDs of an integrated health care system in Northern California between 2015 and 2021. Participants were adult (aged >17 years) health plan members with a chief concern of headache. Exclusions were prior diagnoses of subarachnoid hemorrhage, unruptured intracranial aneurysm, cerebral arteriovenous malformation, or cerebrospinal fluid shunt. Data were analyzed from October to November 2023.

Exposures

CT cerebral angiography and/or lumbar puncture during the ED encounter.

Main Outcomes and Measures

Primary and secondary outcomes were 14-day and 90-day unruptured intracranial aneurysm detection, respectively. Safety outcomes were missed diagnoses of subarachnoid hemorrhage or bacterial meningitis. The annual incidence of unruptured intracranial aneurysm detection was normalized to the incidence of subarachnoid hemorrhage (UIA:SAH ratio). Average annualized percentage changes were quantified using joinpoint regression analysis.

Results

Among 198 109 included ED encounters, the mean (SD) age was 47.5 (18.4) years; 140 001 patients (70.7%) were female; 29 035 (14.7%) were Black or African American, 59 896 (30.2%) were Hispanic or Latino, and 75 602 (38.2%) were White. Per year, CT cerebral angiography use increased (18.8%; 95% CI, 17.7% to 20.3%) and lumbar punctures decreased (-11.1%; 95% CI, -12.0% to -10.4%), with a corresponding increase in the 14-day UIA:SAH ratio (3.5%; 95% CI, 0.9% to 7.4%). Overall, computed tomography cerebral angiography use increased 6-fold relative to lumbar puncture, with a 33% increase in the detection of UIA. Results were similar at 90 days and robust to sensitivity analyses. Subarachnoid hemorrhage (1004 cases) and bacterial meningitis (118 cases) were misdiagnosed in 5% and 18% of cases, respectively, with no annual trends (P = .34; z1003 = .95 and P = .74; z117 = -.34, respectively).

Conclusions and Relevance

In this cohort study of ED patients with headache, increases in CT cerebral angiography use were associated with fewer lumbar punctures and higher detection of unruptured intracranial aneurysms, with no significant change in missed diagnoses of subarachnoid hemorrhage or bacterial meningitis. While this shift in diagnostic strategy appeared safe in the short-term, the long-term consequences remain unclear.

Diagnosis and management of subarachnoid haemorrhage

Aneurysmal subarachnoid haemorrhage (aSAH) presents a challenge to clinicians because of its multisystem effects. Advancements in computed tomography (CT), endovascular treatments, and neurocritical care have contributed to declining mortality rates. The critical care of aSAH prioritises cerebral perfusion, early aneurysm securement, and the prevention of secondary brain injury and systemic complications. Early interventions to mitigate cardiopulmonary complications, dyselectrolytemia and treatment of culprit aneurysm require a multidisciplinary approach. Standardised neurological assessments, transcranial doppler (TCD), and advanced imaging, along with hypertensive and invasive therapies, are vital in reducing delayed cerebral ischemia and poor outcomes. Health care disparities, particularly in the resource allocation for SAH treatment, affect outcomes significantly, with telemedicine and novel technologies proposed to address this health inequalities. This article underscores the necessity for comprehensive multidisciplinary care and the urgent need for large-scale studies to validate standardised treatment protocols for improved SAH outcomes.

Perioperative stroke

Ischaemic or haemorrhagic perioperative stroke (that is, stroke occurring during or within 30 days following surgery) can be a devastating complication following surgery. Incidence is reported in the 0.1-0.7% range in adults undergoing non-cardiac and non-neurological surgery, in the 1-5% range in patients undergoing cardiac surgery and in the 1-10% range following neurological surgery. However, higher rates have been reported when patients are actively assessed and in high-risk populations. Prognosis is significantly worse than stroke occurring in the community, with double the 30-day mortality, greater disability and diminished quality of life among survivors. Considering the annual volume of surgeries performed worldwide, perioperative stroke represents a substantial burden. Despite notable differences in aetiology, patient populations and clinical settings, existing clinical recommendations for perioperative stroke are extrapolated mainly from stroke in the community. Perioperative in-hospital stroke is unique with respect to the stroke occurring in other settings, and it is essential to apply evidence from other settings with caution and to identify existing knowledge gaps in order to effectively guide patient care and future research.

MicroRNA-124 conducts neuroprotective effect via inhibiting AK4/ATF3 after subarachnoid hemorrhage

Spontaneous subarachnoid hemorrhage (SAH) accounts for approximately 5% of all cases of stroke. SAH is correlated with elevated rates of mortality and disability. Despite significant advancements in comprehending the pathogenesis and surgical management, efficacious clinical interventions remain restricted, and the prognosis is yet to be enhanced. MicroRNAs play a crucial role in various pathological processes in organisms. Revealing these regulatory processes is conducive to the development of new treatment methods. MicroRNA-124 is highly expressed in the nervous system and has significant research value for SAH. This study aims to explore the role of miR-124 in the early post-SAH period on neural function and verify whether it is involved in the pathological and physiological processes of SAH. In this study, we used methods such as comparing the expression levels of miR-124 in cerebrospinal fluid, establishing a rat SAH model, and a mouse embryonic primary neuron hemoglobin stimulation model to verify the downstream proteins of miR-124 in SAH. Through transfection techniques, we adjusted the expression of this small RNA in Vitro and in Vivo models using miR-124 inhibitor and mimic in the primary neuron hemoglobin stimulation model and rat SAH model, and observed the phenotype. Finally, by consulting the literature and verifying in Vivo and in Vitro methods, AK4 and downstream molecule ATF3 were identified as downstream targets of miR-124.

Subarachnoid haemorrhage or traumatic lumbar puncture. Differentiation by cerebrospinal fluid parameters in a multivariable approach

Lumbar puncture (LP) is recommended in patients with thunderclap headache and negative computed tomography to rule out spontaneous subarachnoid haemorrhage (SAH). Blood contamination of cerebrospinal fluid (CSF) due to traumatic LP poses a diagnostic dilemma. Therefore, routine CSF parameters were investigated to distinguish between SAH and a traumatic LP. CSF red blood cell (RBC), white blood cell (WBC) count, total protein, CSF colour and supernatant were used for group comparisons of patients with SAH and 'symptomatic controls'. Due to variable time intervals between bleeding onset and LP in SAH patients in contrast to patients with traumatic LP, where blood contamination of CSF occurs at the time of LP, CSF variables were adjusted for decay in time to allow comparability. Logistic regression analysis identified bloody CSF [odds ratio (OR) 32.6], xanthochromic supernatant [OR 15.5] and WBCadjusted [OR 4.5 (per increase of 100/µl)] as predictors of SAH, while age, sex and CSF total proteinadjusted were no predictors. Optimal cut-point of RBCadjusted (determined at day 1 after bleeding) was > 3667/µl to identify SAH patients with a 97% sensitivity and 94% specificity. Combination of low RBC and clear CSF supernatant was found in none of SAH patients. Combined CSF RBC count and CSF supernatant reliably distinguished traumatic LP from SAH.

Medical Malpractice and the Neurologist: Specific Neurological Claims

This chapter highlights the most frequently encountered neurological malpractice claims. The format is designed to provide a rudimentary understanding of how lawsuits arise and thereby focus discussion on adapting practice patterns to improve patient care and minimize liability risk.

2023 Guideline for the Management of Patients With Aneurysmal Subarachnoid Hemorrhage: A Guideline From the American Heart Association/American Stroke Association

AIM

The "2023 Guideline for the Management of Patients With Aneurysmal Subarachnoid Hemorrhage" replaces the 2012 "Guidelines for the Management of Aneurysmal Subarachnoid Hemorrhage." The 2023 guideline is intended to provide patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with aneurysmal subarachnoid hemorrhage.

METHODS

A comprehensive search for literature published since the 2012 guideline, derived from research principally involving human subjects, published in English, and indexed in MEDLINE, PubMed, Cochrane Library, and other selected databases relevant to this guideline, was conducted between March 2022 and June 2022. In addition, the guideline writing group reviewed documents on related subject matter previously published by the American Heart Association. Newer studies published between July 2022 and November 2022 that affected recommendation content, Class of Recommendation, or Level of Evidence were included if appropriate. Structure: Aneurysmal subarachnoid hemorrhage is a significant global public health threat and a severely morbid and often deadly condition. The 2023 aneurysmal subarachnoid hemorrhage guideline provides recommendations based on current evidence for the treatment of these patients. The recommendations present an evidence-based approach to preventing, diagnosing, and managing patients with aneurysmal subarachnoid hemorrhage, with the intent to improve quality of care and align with patients' and their families' and caregivers' interests. Many recommendations from the previous aneurysmal subarachnoid hemorrhage guidelines have been updated with new evidence, and new recommendations have been created when supported by published data.

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.

An ultrafast brain MRI technique for evaluating acute neurologic deficits in the emergency department

Herein we share our preliminary experience with an ultrafast brain MRI technique for use in the ED consisting of axial T1-weighted (40 s), axial T2-weighted (62 s), axial diffusion-weighted (80 s), axial FLAIR (96 s), axial T2* (6 s), and axial susceptibility-weighted (108 s) imaging for a total scan time of 6 min and 53 s. Utilization of this ultrafast technique yields an efficient assessment of the brain, decreases ED length of stay and inpatient observation admissions, and may obviate the need for vascular imaging with either CTA or MRA in the ED.

Time to CT scan for patients with acute severe neurological symptoms: a quality assurance study

Emergent brain computed tomography (CT) scan allows for identification of patients presenting with acute severe neurological symptoms in whom medical and surgical interventions may be lifesaving. The aim of this study was to evaluate if time to CT from arrival at the emergency department exceeded 30 min in patients admitted with acute severe neurological symptoms. This was a retrospective register-based quality assurance study. We identified patients admitted to the emergency department with acute severe neurological symptoms between April 1st, 2016 and September 30th, 2020. Data were retrieved from the registry of acute medical team activations. We considered that time to CT from arrival at the emergency department should not exceed 30 min in more than 10% of patients. A total of 559 patients were included. Median time from arrival at the emergency department until CT scan was 24 min (IQR 16–35) in children (< 18 years), 10 min (IQR 7–17) for adults (18–59 years), and 11 min (IQR 7–16) for elders (> 60 years). This time interval exceeded 30 min for 8.2% (95% CI 6.1–10.9) of all included patients, 35.3% of children, 5.9% of adults, and 8.6% of elders. No children died within 30 days. The 30-day mortality was 21.3% (95% CI 16.4–27) in adults, and 43.9% (95% CI 38.2–49.8) in elders. Time from arrival at our emergency department until brain CT scan exceeded 30 min in 8.2% of all included patients but exceeded the defined quality aim in children and could be improved.

Neuroimaging of Headache: Indications and Controversies

Headache is a common presenting symptom in the ambulatory setting that often prompts imaging. The increased use and associated health care money spent in the setting of headache have raised questions about the cost-effectiveness of neuroimaging in this setting. Neuroimaging for headache in most cases is unlikely to reveal significant abnormality or impact patient management. In this article, reasons behind an observed increase in neuroimaging and its impact on health care expenditures are discussed. The typical imaging modalities available and various imaging guidelines for common clinical headache scenarios are presented, including recommendations from the American College of Radiology.

Performance of Automated RAPID Intracranial Hemorrhage Detection in Real-World Practice: A Single-Institution Experience

BACKGROUND AND PURPOSE

Intracranial hemorrhage (ICH) is a common finding in patients presenting to the emergency department with acute neurological symptoms. Noncontrast head computed tomography (NCCT) is the primary modality for assessment and detection of ICH in the acute setting. RAPID ICH software aims to automatically detect ICH on NCCT and was previously shown to have high accuracy when applied to a curated test data set. Here, we measured the test performance characteristics of RAPID ICH software in detecting ICH on NCCT performed in patients undergoing emergency stroke evaluation at a tertiary academic comprehensive stroke center.

MATERIALS AND METHODS

This retrospective study assessed consecutive patients over a 6-month period who presented with acute neurological symptoms suspicious for stroke and underwent NCCT with RAPID ICH postprocessing. RAPID ICH detection was compared with the interpretation of a reference standard comprising a board-certified or board-eligible neuroradiologist, or in cases of discrepancy, adjudicated by a consensus panel of 3 neuroradiologists. Accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of RAPID ICH for ICH detection were determined.

RESULTS

Three hundred seven NCCT scans were included in the study. RAPID ICH correctly identified 34 of 37 cases with ICH and 228 of 270 without ICH. RAPID ICH had a sensitivity of 91.9% (78.1%-98.3%), specificity of 84.4% (79.6%-88.6%), NPV of 98.7% (96.3%-99.6%), PPV of 44.7% (37.6%-52.1%), and overall accuracy of 85.3% (80.9%-89.1%).

CONCLUSIONS

In a real-world scenario, RAPID ICH software demonstrated high NPV but low PPV for the presence of ICH when evaluating possible stroke patients.

Labeling Noncontrast Head CT Reports for Common Findings Using Natural Language Processing

BACKGROUND AND PURPOSE

Prioritizing reading of noncontrast head CT examinations through an automated triage system may improve time to care for patients with acute neuroradiologic findings. We present a natural language-processing approach for labeling findings in noncontrast head CT reports, which permits creation of a large, labeled dataset of head CT images for development of emergent-finding detection and reading-prioritization algorithms.

MATERIALS AND METHODS

In this retrospective study, 1002 clinical radiology reports from noncontrast head CTs collected between 2008 and 2013 were manually labeled across 12 common neuroradiologic finding categories. Each report was then encoded using an n-gram model of unigrams, bigrams, and trigrams. A logistic regression model was then trained to label each report for every common finding. Models were trained and assessed using a combination of L2 regularization and 5-fold cross-validation.

RESULTS

Model performance was strongest for the fracture, hemorrhage, herniation, mass effect, pneumocephalus, postoperative status, and volume loss models in which the area under the receiver operating characteristic curve exceeded 0.95. Performance was relatively weaker for the edema, hydrocephalus, infarct, tumor, and white-matter disease models (area under the receiver operating characteristic curve > 0.85). Analysis of coefficients revealed finding-specific words among the top coefficients in each model. Class output probabilities were found to be a useful indicator of predictive error on individual report examples in higher-performing models.

CONCLUSIONS

Combining logistic regression with n-gram encoding is a robust approach to labeling common findings in noncontrast head CT reports.

The added value of cerebrospinal fluid analysis in patients with subarachnoid hemorrhage after negative noncontrast CT

OBJECTIVE

In patients presenting within 6 hours after signs and symptoms of suspected subarachnoid hemorrhage (SAH), CSF examination is judged to be no longer necessary if a noncontrast CT (NCCT) scan rules out SAH. In this study, the authors evaluated the performance of NCCT to rule out SAH in patients with positive CSF findings.

METHODS

Between January 2006 and April 2018, 1657 patients were admitted with a nontraumatic SAH. Of these patients, 1546 had positive SAH findings on the initial NCCT and 111 patients had an NCCT scan that was reported as negative in the acute setting, but with positive CSF examination for subarachnoid blood. Demographic data, World Federation of Neurosurgical Societies grade, and SAH time points (ictus, time of NCCT, and time of lumbar puncture) were collected. All 111 NCCT scans were reevaluated by an experienced neuroradiologist.

RESULTS

Of the 111 patients with positive CSF findings, SAH was initially missed on NCCT in 25 patients (23%). Reevaluation of 21 patients presenting within 6 hours of symptom onset confirmed NCCT negative findings in 12 (5 aneurysms), an aneurysmal SAH (aSAH) pattern in 8 (7 aneurysms), and a perimesencephalic pattern in 1 patient. Reevaluation of 90 patients presenting after 6 hours confirmed negative NCCT findings in 74 patients (37 aneurysms), aSAH pattern in 10 (4 aneurysms), and a perimesencephalic pattern in 6 (2 aneurysms).

CONCLUSIONS

CSF examination is still mandatory to rule out SAH as NCCT can fail to show blood, even within 6 hours after symptom onset. In addition, the diagnosis SAH was frequently missed during initial reporting.

Management of patients presenting to the emergency department with sudden onset severe headache: systematic review of diagnostic accuracy studies

Objective

Advances in imaging technologies have precipitated uncertainty and inconsistency in the management of neurologically intact patients presenting to the Emergency Department (ED) with non-traumatic sudden onset severe headache with a clinical suspicion of subarachnoid haemorrhage (SAH). The objective of this systematic review was to evaluate diagnostic strategies in these patients.

Methods

Studies assessing any decision rule or diagnostic test for evaluating neurologically intact adults with a severe headache, reaching maximum intensity within 1 hour, were eligible. Eighteen databases (including MEDLINE and Embase) were searched. Quality was assessed using QUADAS-2. Where appropriate, hierarchical bivariate meta-analysis was used to synthesise diagnostic accuracy results.

Results

Thirty-seven studies were included. Eight studies assessing the Ottawa SAH clinical decision rule were pooled; sensitivity 99.5% (95% CI 90.8 to 100), specificity 24% (95% CI 15.5 to 34.4). Four studies assessing CT within 6 hours of headache onset were pooled; sensitivity 98.7% (95% CI 96.5 to 100), specificity 100% (95% CI 99.7 to 100). The sensitivity of CT beyond 6 hours was considerably lower (≤90%; 2 studies). Three studies assessing lumbar puncture (LP; spectrophotometric analysis) following negative CT were pooled; sensitivity 100% (95% CI 100 to 100), specificity 95% (95% CI 86.0 to 98.5).

Conclusion

The Ottawa SAH Rule rules out further investigation in only a small proportion of patients. CT undertaken within 6 hours (with expertise of a neuroradiologist or radiologist who routinely interprets brain images) is highly accurate and likely to be sufficient to rule out SAH; CT beyond 6 hours is much less sensitive. The CT–LP pathway is highly sensitive for detecting SAH and some alternative diagnoses, although LP results in some false positive results.

The emergency department incidence of incidental intracranial aneurysm on computed tomography angiography (EPIC-ACT) study

BACKGROUND

Subarachnoid hemorrhage has been traditionally ruled-out in the emergency department (ED) through computed tomography (CT) followed by lumbar puncture if indicated. Mounting evidence suggests that non-contrast CT with CT angiography (CTA) can safely rule-out subarachnoid hemorrhage and obviate the need for lumbar puncture, but adoption of this approach is hindered by concerns of identifying incidental aneurysms. This study aims to estimate the incidence of incidental aneurysms identified on CTA head and neck in an ED population.

METHODS

This was a health records review of all patients ≥ 18 years who underwent CTA head and neck for any indication at four large urban tertiary care EDs over a 3 month period. Patients were excluded if they underwent CT venogram only, had previously documented intracranial aneurysms, or had intracranial hemorrhage with or without aneurysm. Imaging reports were reviewed by two independent physicians before extracting relevant demographic (age, sex), clinical (CTAS level, CEDIS primary complaint) and radiographic (number, size, and location of aneurysms) information. The incidence rate of incidental aneurysms was calculated.

RESULTS

A total of 1089 CTA studies were reviewed with a 3.3% (95% CI 2.3-4.6) incidence of incidental intracranial aneurysms. The median size of incidental aneurysms was 4 mm (0.7-11) and 10 (27.7%) patients had multiple aneurysms. Patients with incidental aneurysms did not differ based on mean age, sex, and CTAS levels.

CONCLUSIONS

The "risk" of discovering an incidental aneurysm is 3.3%. Clinicians should not be deterred from using CTA in the appropriate clinical settings. These estimates can inform shared decision-making conversations with patients when comparing subarachnoid hemorrhage rule-out options.

Therapeutic Approaches for Cerebrovascular Dysfunction After Aneurysmal Subarachnoid Hemorrhage: An Update and Future Perspectives

Aneurysmal subarachnoid hemorrhage (aSAH) is a severe subtype of stroke occurring at a relatively young age with a significant socioeconomic impact. Treatment of aSAH includes early aneurysm exclusion, intensive care management, and prevention of complications. Once the aneurysm rupture occurs, blood spreading within the subarachnoid space triggers several molecular pathways causing early brain injury and delayed cerebral ischemia. Pathophysiologic mechanisms underlying brain injury after aSAH are not entirely characterized, reflecting the difficulties in identifying effective therapeutic targets for patients with aSAH. Although the improvements of the last decades in perioperative management, early diagnosis, aneurysm exclusion techniques, and medical treatments have increased survival, vasospasm and delayed cerebral infarction are associated with high mortality and morbidity. Clinical practice can rely on a few specific therapeutic agents, such as nimodipine, a calcium-channel blocker proved to reduce severe neurologic deficits in these patients. Therefore, new pharmacologic approaches are needed to improve the outcome of this life-threatening condition, as well as a tailored rehabilitation plan to maintain the quality of life in aSAH survivors. Several clinical trials are investigating the efficacy and safety of emerging drugs, such as magnesium, clazosentan, cilostazol, interleukin 1 receptor antagonists, deferoxamine, erythropoietin, and nicardipine, and continuous lumbar drainage in the setting of aSAH. This narrative review focuses on the most promising therapeutic interventions after aSAH.

Evaluating xanthochromia in the diagnosis of subarachnoid haemorrhage in Scotland in the Era of modern computed tomography

AIM

Cerebrospinal fluid (CSF) analysis for xanthochromia is routinely used to exclude subarachnoid haemorrhage (SAH). In this study, we evaluated the sensitivity and specificity of xanthochromia (by NEQAS-spectrophotometry) in routine clinical practice in three acute hospitals, in patients with suspected SAH. We explored whether including CSF red cell count (RCC) with xanthochromia improved diagnostic accuracy.

METHODS

In this retrospective analysis, all xanthochromia results were assessed over three consecutive years. Clinical information and Registry data were analysed to find all patients diagnosed with SAH. We correlated xanthochromia data with clinical and radiological findings.

RESULTS

There were 1761 xanthochromia performed. Of these, 26 (1.5%) were positive, 1624 (92%) negative and 72 (4.1%) were inconclusive. Of the 26 tests that were positive, 9 (35%) had confirmed SAH, 17 (65%) were falsely positive, with no false negative tests in our series. Xanthochromia identified 6% of all SAH diagnosed in the study. Incorporating RCC <1000 with xanthochromia, reducing false positive tests by 38% and inconclusive test by 85%.

CONCLUSION

The positive yield of xanthochromia is low but identified 6% of SAH. NEQAS-spectrophotometry is an excellent diagnostic method with 100% sensitivity, 99% specificity. Incorporating RCC markedly reduces false positive and inconclusive tests reducing need for further imaging.

Characterization of Subarachnoid Hyperdensities After Thrombectomy for Acute Stroke Using Dual-Energy CT

BACKGROUND AND OBJECTIVES

The presence of post-interventional subarachnoid hyperdensities (SA-HD) is a relatively common finding after mechanical thrombectomy (MT). We aimed to assess the incidence, characteristics, clinical relevance and predictors of SA-HD after MT as categorized through the use of post-interventional Dual Energy-CT (DE-CT).

METHODS

A single-center consecutive series of acute stroke patients treated with MT were retrospectively reviewed. Post-treatment SA-HD were defined as incident extra-axial hyperdensities in a follow-up DE-CT performed within a median of 8 hours after MT. SA-HD were further classified according to their content (isolated contrast extravasation versus blood extravasation) and extension [diffuse (hyperdensities in more than one extraparenchymal compartments) versus non-diffuse]. Adjusted logistic regression models assessed the association of SA-HD with pretreatment and procedural variables and with bad clinical outcome (shift towards worse categories in the ordinal Rankin Scale at 90 days).

RESULTS

SA-HD were observed in 120 (28%) of the 424 included patients (isolated contrast extravasation n=22, blood extravasation n=98). In this group, SA-HD were diffuse in 72 (60%) patients (isolated contrast extravasation n=7, blood extravasation n=65) and non-diffuse in 48 (40%) patients (isolated contrast extravasation n=15, blood extravasation n=33). Diffuse SA-HD were significantly associated with worse clinical outcome in adjusted models (cOR=2.3, 95%CI=1.36-4.00, p=0.002), unlike the specific SA-HD content alone. In contrast with the absence of SA-HD, only the diffuse pattern with blood extravasation was significantly associated with worse clinical outcome (cOR=2.4, 95%CI=1.36-4.15, p=0.002). Diffuse SA-HD patterns were predicted by M2 occlusions, more thrombectomy passes and concurrent parenchymal hematomas.

DISCUSSION

In our cohort of patients imaged within a median of 8 hours after MT, post-interventional SA-HD showed a diffuse pattern in 17% of thrombectomies and were associated with more arduous procedures. Diffuse SA-HD but not local collections of blood or contrast extravasations were associated with an increased risk of poor outcome and death. These findings reinforce the need for improvement in reperfusion strategies.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that in individuals with proximal carotid artery territory occlusions treated with mechanical thrombectomy, diffuse post-interventional subarachnoid hyperdensities on imaging 8 hours post-procedure are associated with worse clinical outcomes at 90 days.

Sensitivity of modern multislice CT for subarachnoid haemorrhage at incremental timepoints after headache onset: a 10-year analysis

BACKGROUND

CT performed within 6 hours of headache onset is highly sensitive for the detection of subarachnoid haemorrhage (SAH). Beyond this time frame, if the CT is negative for blood, a lumbar puncture is often performed. Technology improvements in image noise reduction, resolution and motion artefact have enhanced the performance of multislice CT (MSCT) and may have further improved sensitivity. We aimed to describe how the sensitivity to SAH of modern MSCT changes with time from headache onset.

METHODS

This was a retrospective analysis of electronic data collected as part of routine care among all patients presenting to Christchurch Hospital diagnosed with a SAH between 1 January 2008 and 31 December 2017. Patients were imaged with MSCT. The primary outcome was the proportion of patients with spontaneous aneurysmal SAH (identified via coding and confirmed by clinical and radiological records) that had a positive MSCT. The secondary outcome was the proportion of patients with any type of spontaneous SAH that had a positive MSCT.

RESULTS

There were 347 patients with an SAH of whom 260 were aneurysmal SAH. MSCT identified 253 (97.3%) of all aneurysmal SAH and 332 (95.7%) of all SAH. The sensitivity of MSCT was 99.6% (95% CI 97.6 to 100) for aneurysmal SAH and 99.0% (95% CI 97.1 to 99.8) for all SAH at 48 hours after headache onset. At 24 hours after headache onset, the sensitivity for aneurysmal SAH was 100% (95% CI 98.3 to 100).

CONCLUSION

These data suggest that it may be possible to extend the timeframe from headache onset within which modern MSCT can be used to rule out aneurysmal SAH.

Artificial Intelligence Trained by Deep Learning Can Improve Computed Tomography Diagnosis of Nontraumatic Subarachnoid Hemorrhage by Nonspecialists

Subarachnoid hemorrhage (SAH) is a serious cerebrovascular disease with a high mortality rate and is known as a disease that is hard to diagnose because it may be overlooked by noncontrast computed tomography (NCCT) examinations that are most frequently used for diagnosis. To create a system preventing this oversight of SAH, we trained artificial intelligence (AI) with NCCT images obtained from 419 patients with nontraumatic SAH and 338 healthy subjects and created an AI system capable of diagnosing the presence and location of SAH. Then, we conducted experiments in which five neurosurgery specialists, five nonspecialists, and the AI system interpreted NCCT images obtained from 135 patients with SAH and 196 normal subjects. The AI system was capable of performing a diagnosis of SAH with equal accuracy to that of five neurosurgery specialists, and the accuracy was higher than that of nonspecialists. Furthermore, the diagnostic accuracy of four out of five nonspecialists improved by interpreting NCCT images using the diagnostic results of the AI system as a reference, and the number of oversight cases was significantly reduced by the support of the AI system. This is the first report demonstrating that an AI system improved the diagnostic accuracy of SAH by nonspecialists.

Diagnosis and Treatment of Unruptured Intracranial Aneurysms and Aneurysmal Subarachnoid Hemorrhage

Unruptured intracranial aneurysms (UIAs) are commonly acquired vascular lesions that form an outpouching of the arterial wall due to wall thinning. The prevalence of UIAs in the general population is 3.2%. In contrast, an intracranial aneurysm may be manifested after rupture with classic presentation of a thunderclap headache suggesting aneurysmal subarachnoid hemorrhage (SAH). Previous consensus suggests that although small intracranial aneurysms (<7 mm) are less susceptible to rupture, aneurysms larger than 7 mm should be treated on a case-by-case basis with consideration of additional risk factors of aneurysmal growth and rupture. However, this distinction is outdated. The PHASES score, which comprises data pooled from several prospective studies, provides precise estimates by considering not only the aneurysm size but also other variables, such as the aneurysm location. The International Study of Unruptured Intracranial Aneurysms is the largest observational study on the natural history of UIAs, providing the foundation to the current guidelines for the management of UIAs. Although SAH accounts for only 3% of all stroke subtypes, it is associated with considerable burden of morbidity and mortality. The initial management is focused on stabilizing the patient in the intensive care unit with close hemodynamic and serial neurologic monitoring with endovascular or open surgical aneurysm treatment to prevent rebleeding. Since the results of the International Subarachnoid Aneurysm Trial, treatment of aneurysmal SAH has shifted from surgical clipping to endovascular coiling, which demonstrated higher odds of survival free of disability at 1 year after SAH. Nonetheless, aneurysmal SAH remains a public health hazard and is associated with high rates of disability and death.

Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage is a neurologic emergency that requires immediate patient stabilization and prompt diagnosis and treatment. Early measures should focus on principles of advanced cardiovascular life support. The aneurysm should be evaluated and treated in a comprehensive stroke center by a multidisciplinary team capable of endovascular and, operative approaches. Once the aneurysm is secured, the patient is best managed by a dedicated neurocritical care service to prevent and manage complications, including a syndrome of delayed neurologic decline. The goal of such specialized care is to prevent secondary injury, reduce length of stay, and improve outcomes for survivors of the disease.

Is a Lumbar Puncture Required to Rule Out Atraumatic Subarachnoid Hemorrhage in Emergency Department Patients With Headache and Normal Brain Computed Tomography More Than Six Hours After Symptom Onset?

BACKGROUND

Atraumatic subarachnoid hemorrhage (SAH) is a deadly condition that most commonly presents as acute, severe headache. Controversy exists concerning evaluation of SAH based on the time from onset of symptoms, specifically if the headache occurred > 6 h prior to patient presentation.

CLINICAL QUESTION

Do patients undergoing evaluation for atraumatic SAH who have a negative computed tomography (CT) scan of the head obtained more than 6 h after symptom onset require a subsequent lumbar puncture to rule out the diagnosis?

EVIDENCE REVIEW

Studies retrieved included a retrospective cohort study, two prospective cohort studies, and a case-control study. These studies provide estimates of the diagnostic accuracy of head CT imaging obtained > 6 h from symptom onset and diagnostic test characteristics of subsequent lumbar puncture.

CONCLUSION

The probability of SAH above which emergency clinicians should perform a lumbar puncture is 1.0%. This threshold is essentially the same as the estimated probability of SAH in patients with a negative head CT obtained more than 6 h from symptom onset. Emergency physicians might reasonably decide to either perform or forego this procedure. Consequently, we contend that the decision whether to perform lumbar puncture in these instances is an excellent candidate for shared decision-making.

Two Similar Cases of a Misdiagnosed Anterior Communicating Aneurysm Rupture

The misdiagnosis of a ruptured aneurysm directly endangers patient's life and health due to the high risk of rebleeding and its sequelae. In this paper, we present two uncommon cases of anterior communicating artery aneurysm rupture with a relatively small intracerebral bleeding, seemingly without a diffuse subarachnoid hemorrhage (SAH), and a relatively mild clinical presentation. In these cases, the initial diagnosis failed, leading to missed aneurysmal ruptures. The atypical or mild clinical presentation, and the absence of SAH on computed tomography (CT) and/or magnetic resonance imaging (MRI) scan or absent blood in the cerebrospinal fluid (CSF) are all factors which could lead to a false or delayed diagnosis. Meticulous evaluation of patient's symptoms, CT, MRI scans, and CSF findings are mandatory. The possibility of a small blood clot without a diffuse SAH must be considered.

Pseudosubarachnoid hemorrhage: A systematic review of causes, diagnostic modalities, and outcomes in patients who present with pseudosubarachnoid hemorrhage

Background:

Patients with computed tomography (CT) findings consistent with subarachnoid hemorrhage without evidence of hemorrhage following autopsy or cerebrospinal fluid testing are termed to have pseudosubarachnoid hemorrhage (pSAH).

Methods:

A systematic review of literature was conducted based on the preferred reporting items for systematic reviews and meta-analysis statement. Studies were evaluated for associated cause of pSAH, imaging modality used in assessment, method of confirmatory testing, and clinical outcome.

Results:

Fifty studies were included in qualitative analysis including 197 cases of pSAH. Systematic review revealed 23 studies including 110 patients with pSAH attributed to hypoxic-ischemic brain injury following cardiac arrest. Three studies were included in meta-analysis that quantitatively analyzed differences in CT densities in patients with pSAH and true subarachnoid hemorrhage (true SAH). A random effects model meta-analysis showed a statistically significant decrease in densities in the Sylvian fissure in patients with pSAH compared to true SAH and a statistically significant decrease in densities in adjacent parenchyma in patients with pSAH compared to true SAH. Systematic review further revealed 32 patients with pSAH associated with spontaneous intracranial hypotension, 11 patients with pSAH related to infectious etiologies, 15 patients with pSAH associated with subdural hemorrhage, 20 cases of pSAH related to hyperhemoglobinemia, 2 cases related to valproate toxicity, and individual cases related to hyponatremia, diabetic ketoacidosis, sudden infant death syndrome, cerebellar infarction, and dialysis disequilibrium syndrome.

Conclusion:

This study is the first systematic review of causes, diagnostic modalities, and outcomes in patients who present with pSAH. A diagnosis of pSAH may be considered following assessment of CT densities following cardiac arrest.

Novel Subgroups in Subarachnoid Hemorrhage and Their Association With Outcomes-A Systematic Review and Meta-Regression

Background and Purpose: Subarachnoid hemorrhage (SAH) has long been classified into two main forms, aneurysmal SAH (aSAH) and non-aneurysmal SAH (naSAH), but the related risk factors for aSAH and naSAH are heterogeneous. Our objective was to determine the risk factors for SAH of known or unknown origin with respect to diagnostic evaluation in a large patient cohort. We sought to determine whether our classification system can further predict middle long-term stroke and death. Methods: We performed a systematic review and meta-analysis to identify risk factors for each SAH subtype. The discovery phase analyzed 11 risk factors from case studies in the literature. Kruskal-Wallis, Cox regression, logistic regression, and Kaplan-Meier analyses were used to compare the two groups. Results: A total of 14,904 (34.53%) male and 22,801 (52.84%) female patients were eligible for this study. At a median follow-up of 45.6 months, the 5-years overall survival was 97.768% (95% CI: 0.259-0.292) for aSAH patients and 87.904% (95% CI: 1.459-1.643) for naSAH patients. The 10-years survival rate was 93.870% (95% CI: 2.075-3.086) and 78.115% (95% CI: 2.810-3.156), respectively. Multi-risk factor subgroups showed significant intergroup differences. We identified eight risk factors (drugs, trauma, neoplastic, vessels lesion, inflammatory lesion, blood disease, aneurysm, peri-mesencephalic hemorrhage) using logistic regression, which were optimally differentiated among the aSAH [aSAH-S (AUC: 1), a-d-SAH (AUC: 0.9998), aSAH-T (AUC: 0.9199), aSAH-N (AUC: 0.9433), aSAH-V (AUC: 1), aSAH-I (AUC: 0.9954), a-bd-SAH (AUC: 0.9955)] and naSAH [na-pmSAH (AUC: 0.9979), na-ni-ivl-SAH (AUC: 1), na-t-SAH (AUC: 0.9997), na-ne-SAH (AUC: 0.9475), na-d-SAH (AUC: 0.7676)] subgroups. These models were applied in a parallel cohort, showing eight risk factors plus survival rates to predict the prognosis of SAH. Conclusions: The classification of risk factors related to aSAH and naSAH is helpful in the diagnosis and prediction of the prognosis of aSAH and naSAH patients. Further validation is needed in future clinical applications.

Management of thunderclap headache in the emergency room: A retrospective cohort study

INTRODUCTION

The evaluation of red flags is crucial for the accurate the diagnosis of headache disorders, especially for thunderclap headache. We analysed if secondary headache disorders were adequately ruled out in patients that presented to the emergency room with thunderclap headache.

METHODS

In this retrospective cohort study, we screened all patients that visited the emergency room for headache, including those that described thunderclap headache. We measured the frequency with which secondary causes were not adequately ruled out. We analysed the order of the exams, the final diagnosis, and the time elapsed between arrival, initial request for imaging, and the completion of the imaging.

RESULTS

We screened 2132 patients, and 42 (1.9%) fulfilled eligibility criteria. Mean age was 43.1 ± 17.1 years, and 57% of patients were female. For 22 (52.4%) patients, the work-up was incomplete. Vascular study was missing in 16 (38.1%) patients, cerebrospinal fluid evaluation in nine (21.4%), and magnetic resonance imaging in seven (16.7%), with multiple assessments missing in six (14.3%). There were ten different combinations in which the exams were performed, with the most frequent being the second exam's cerebral spinal fluid evaluation in 18 (52.9%) and the computed tomography angiogram in 10 (29.4%). A secondary cause of thunderclap headache was found in 16 (38.1%) patients, and four (9.5%) had a primary headache diagnosis after an adequate and complete study.

CONCLUSIONS

Thunderclap onset was described in one of every 50 patients that visited the emergency room for headache. More than half of these patients were not adequately managed. More than a third of thunderclap headache patients had a secondary cause.

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.

Headache in the Emergency Department: Avoiding Misdiagnosis of Dangerous Secondary Causes, An Update

In the initial assessment of the headache patient, the emergency physician must consider several dangerous secondary causes of headache. A thorough history and physical examination, along with consideration of a comprehensive differential diagnosis may alert the emergency physician to the diagnosis of a secondary headache particularly when the history is accompanied by any of the following clinical features: sudden/severe onset, focal neurologic deficits, altered mental status, advanced age, active or recent pregnancy, coagulopathy, malignancy, fever, visual deficits, and/or loss of consciousness.

Determining the Diagnostic Utility of Lumbar Punctures in Computed Tomography Negative Suspected Subarachnoid Hemorrhage: A Systematic Review and Meta-analysis

BACKGROUND

While headache is a common neurologic symptom, subarachnoid hemorrhage (SAH) is a rare and potentially catastrophic cause of sudden-onset severe headache. The utility of the imaging modalities and interventional procedures are central to the investigation of the causes of headache; however, they are not without their limitations, risks, and complications.

METHODS

A meta-analysis in accordance with the Preferred Reporting for Systematic Reviews and Meta-analysis guidelines was conducted searching PubMed, EMBASE, and Google Scholar. Patients investigated for suspected subarachnoid hemorrhage (SAH) with a negative computed tomography (CT) and positive lumbar puncture (LP) and final diagnosis of SAH were included. The sensitivity of LP in the context of a negative CT and vsubsequent imaging confirming the cause of SAH (computed tomography angiography, magnetic resonance angiography, digital subtraction angiography [DSA]) was quantified. The pooled data were analyzed using the DerSimonian-Laid random effects model.

RESULTS

Four studies with 2782 patients who presented with headache suspicious for SAH were included with an initial negative CT report and a subsequent LP to rule out SAH. All included studies had an observational prospective cohort design. A combined pooled proportion of 0.383 (0.077, 0.756); 0.086 (0.007, 0.238); and 0.22 (0.04, 0.49) for LP+, DSA+, and DSA/computed tomography angiography+ investigations were estimated with a 95% confidence interval.

CONCLUSIONS

The current clinical workflow of an LP after a negative CT head for a patient presenting with a sudden-onset severe headache is observed to have a high enough proportion to warrant its continued use despite the sensitivity of modern CT scanners of ≥97%.

Spectrophotometry of cerebrospinal fluid for xanthochromia is a sensitive and specific test for subarachnoid bleeding but adds little to computed tomography

Subarachnoid hemorrhage (SAH) is a serious neurological event associated with high morbidity and mortality. Computed tomography of the cerebrum (CTC) is the diagnostic method of choice, but in case of negative CTC but strong suspicion of SAH, lumbar puncture with spectrophotometric analysis of cerebrospinal fluid (CSF) for xanthochromia is performed. We wanted to examine the diagnostic properties of CSF spectrophotometry for xanthochromia testing. We performed a retrospective study of the diagnostic properties of CSF analysis for xanthochromia using spectrophotometry in the diagnosis of SAH. A total of 489 CSF samples were analyzed for xanthochromia, according to international guidelines, from 2009 until 2014 and for 411 of these the patient files were retrieved and examined for final clinical diagnosis and result of CTC. One patient with SAH did not have a positive spectrophotometry report and another patient with SAH had an equivocal report. In four patients did initial CTC not correctly identify SAH. For patients with a negative CTC within six hours of symptom onset spectrophotometry for xanthochromia in the CSF had a diagnostic sensitivity of 100% and a diagnostic specificity of 98.5%. The positive predictive value was 16.7% and the negative predictive value 100%. We conclude that spectrophotometry of CSF for xanthochromia is a sensitive and specific test for diagnosing SAH. However, it seems that an initial CTC identifies almost all patients with SAH. This suggests that in our and similar diagnostic settings, lumbar puncture and testing for xanthochromia might only be relevant in very few cases, if not obsolete.

Diagnosis and Initial Emergency Department Management of Subarachnoid Hemorrhage

Atraumatic subarachnoid hemorrhage represents a small proportion of strokes, but is a true medical emergency that results in significant morbidity and mortality. Making the diagnosis can be challenging and misdiagnosis can result in devastating consequences. There are several time-dependent diagnostic and management considerations for emergency physicians and other frontline providers. This article reviews the most up-to-date literature on the diagnostic workup of subarachnoid hemorrhage, avoiding misdiagnosis, and initial emergency department management recommendations.

ACR Appropriateness Criteria® Headache

Headache is one of the most common human afflictions. In most cases, headaches are benign and idiopathic, and resolve spontaneously or with minor therapeutic measures. Imaging is not required for many types of headaches. However, patients presenting with headaches in the setting of "red flags" such as head trauma, cancer, immunocompromised state, pregnancy, patients 50 years or older, related to activity or position, or with a corresponding neurological deficit, may benefit from CT, MRI, or noninvasive vascular imaging to identify a treatable cause. This publication addresses the initial imaging strategies for headaches associated with the following features: severe and sudden onset, optic disc edema, "red flags," migraine or tension-type, trigeminal autonomic origin, and chronic headaches with and without new or progressive features. 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 include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Pseudo-subarachnoid hemorrhage and gadolinium encephalopathy following lumbar epidural steroid injection

Patients with imaging findings concerning for subarachnoid hemorrhage, however, with no evidence of hemorrhage following autopsy or cerebrospinal fluid testing are diagnosed with having pseudo-subarachnoid hemorrhage. A 73-year-old female presented to the emergency department with altered mental status one day after undergoing a lumbar epidural steroid injection at an outside hospital; a noncontrast computed tomography scan of the head revealed evidence of diffuse hyperdensity within the subarachnoid space concerning for subarachnoid hemorrhage. The patient underwent magnetic resonance imaging which demonstrated diffuse opacification of the cerebrospinal fluid spaces with gadolinium and the diagnoses of pseudo-subarachnoid hemorrhage and gadolinium encephalopathy were made. The combination of the neurologic symptoms related to gadolinium encephalopathy and the radiographic findings of pseudo-subarachnoid hemorrhage can create a clinical presentation nearly identical to ruptured aneurysmal subarachnoid hemorrhage. Patient history, magnetic resonance imaging findings, and temporal changes in computed tomography provide vital tools in establishing a diagnosis of pseudo-subarachnoid hemorrhage, especially after an iatrogenic intrathecal contrast administration.

CT for Treatment Selection in Acute Ischemic Stroke: A Code Stroke Primer

CT is the primary imaging modality used for selecting appropriate treatment in patients with acute stroke. Awareness of the typical findings, pearls, and pitfalls of CT image interpretation is therefore critical for radiologists, stroke neurologists, and emergency department providers to make accurate and timely decisions regarding both (a) immediate treatment with intravenous tissue plasminogen activator up to 4.5 hours after a stroke at primary stroke centers and (b) transfer of patients with large-vessel occlusion (LVO) at CT angiography to comprehensive stroke centers for endovascular thrombectomy (EVT) up to 24 hours after a stroke. Since the DAWN and DEFUSE 3 trials demonstrated the efficacy of EVT up to 24 hours after last seen well, CT angiography has become the operational standard for rapid accurate identification of intracranial LVO. A systematic approach to CT angiographic image interpretation is necessary and useful for rapid triage, and understanding common stroke syndromes can help speed vessel evaluation. Moreover, when diffusion-weighted MRI is unavailable, multiphase CT angiography of collateral vessels and source-image assessment or perfusion CT can be used to help estimate core infarct volume. Both have the potential to allow distinction of patients likely to benefit from EVT from those unlikely to benefit. This article reviews CT-based workup of ischemic stroke for making tPA and EVT treatment decisions and focuses on practical skills, interpretation challenges, mimics, and pitfalls.^©RSNA, 2019.

Excluding subarachnoid haemorrhage within 24 hours: to LP or not to LP?

BACKGROUND AND PURPOSE

Subarachnoid haemorrhage (SAH) is a potentially life-threatening cause of acute headache. Current conventional practice in the United Kingdom (UK) is for head computed tomography (CT) followed by cerebrospinal fluid (CSF) xanthochromia analysis if the head CT is normal. However, with increasing radiological accuracy, head CT alone may be sufficient to exclude SAH without requiring CSF xanthochromia for confirmation. This study aims to determine whether CSF xanthochromia is still required to confirm exclusion of SAH after normal head CT within a tertiary referral centre.

METHODS

Data was obtained from Nottingham University Hospitals (NUH) NHS Trust databases on 999 patients presenting with symptoms suspicious of SAH from 2012 to 2015. All patients had CSF xanthochromia analysis when head CT was normal or inconclusive for suspected SAH.

RESULTS

A total of 179 patients were diagnosed with SAH (17.9%). 176 patients were diagnosed radiologically and 3 patients required further investigations. The 3 of the 802 patients who underwent lumbar puncture (LP) and were identified as having had SAH presented more than 24 hours after ictus. When stratified according to the time of presentation, a normal CT head was observed in those who presented within 24 hours from ictus (sensitivity of 100% [95% CI 92.5-100] and negative predictive value of 100% [97.2-100]).

CONCLUSION

Within a tertiary referral centre for SAH, a normal head CT has a very high negative predictive value to exclude SAH when carried out within 24 hours from ictus provided a 3rd generation CT scanner is utilised, and the scan is reported by a neuroradiologist. CSF xanthochromia analysis in this cohort may still be indicated in those presenting with a high clinical suspicion of SAH and in hospital settings where neuroradiologists or 3rd generation CT scanners are not easily accessible.

Practice Variation in the Diagnosis of Aneurysmal Subarachnoid Hemorrhage: A Survey of US and Canadian Emergency Medicine Physicians

BACKGROUND AND AIMS

Spontaneous subarachnoid hemorrhage (SAH) from a brain aneurysm, if untreated in the acute phase, leads to loss of functional independence in about 30% of patients and death in 27-44%. To evaluate for SAH, the American College of Emergency Physicians (ACEP) Clinical Policy recommends obtaining a non-contrast brain computed tomography (CT) scan followed by a lumbar puncture (LP) if the CT is negative. On the other hand, current evidence from prospectively collected data suggests that CT alone may be sufficient to rule out SAH in patients who present within 6 h of symptom onset while anecdotal evidence suggests that CT angiogram (CTA) may be used to detect aneurysms, which are the probable cause of SAH. Since many different options are available to emergency physicians, we examined their practice pattern variation by observing their diagnostic approaches and their adherence to the ACEP Clinical Policy.

METHODS

We developed, validated, and distributed a survey to emergency physicians at three practice sites: (1) Stanford Healthcare, California, (2) Intermountain Healthcare (five emergency departments), Utah, and (3) Ottawa General Hospital, Toronto. The survey questions examined physician knowledge on CT and LP's test performance and used case-based scenarios to assess diagnostic approaches, variation in practice, and adherence to guidelines. Results were presented as proportions with 95% CIs.

RESULTS

Of the 216 physicians surveyed, we received 168 responses (77.8%). The responses by site were: (1) (n = 38, 23.2%), (2) (n = 70, 42.7%), (3) (n = 56, 34.1%). To the CT and LP test performance question, most physicians indicated that CT alone detects > 90% of SAH in those with a confirmed SAH [n = 150 (89.3%, 95% CI 83.6-93.5]. To the case-based questions, most physicians indicated that they would perform a CTA along with a CT [n = 110 (65.5%, 95% CI 57.8-72.6)], some indicated a LP along with a CT [n = 57, 33.9% 95% CI 26.8-41.6)], and a few indicated both a CTA and a LP [n = 16, 9.5%, 95% CI 5.5-15.0]. We also observed practice site variation in the proportion of physicians who indicated that they would use CTA: (1) (n = 25, 65.8%), (2) (n = 54, 77.1%), and (3) (n = 28, 50.0%) (p = 0.006).

CONCLUSIONS

Survey responses indicate that physicians use some or all of the imaging tests, with or without LP to diagnose SAH. We observed variation in the use of CTA by site and academic setting and divergence from ACEP Clinical Policy.