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.

Decibel Decisions: The Concept of Intracranial Aneurysm Surgery With a Decibel Meter on Two Surgical Cases

The present cases were used to investigate the reliability of the intraoperative decibel meter as an objective method of clipping efficiency in cerebral aneurysm surgery and to assess the impact of this method on the surgical procedure itself. Different methodologies have been developed and applied to directly or indirectly evaluate the placement of a clip, for example, intraoperative digital subtraction angiography (DSA), intraoperative micro-Doppler ultrasonography, and, more recently, indocyanine green (ICG). We included two patients with a previously non-treated unruptured brain aneurysm. In both patients, intraoperative micro-Doppler was used in combination with a decibel meter app. Here, we present the cases of two patients. In patient one, the pre-clipping average sound level/equivalent continuous sound pressure level (Avg/Leq) was 96.7 dB, while the post-clipping Avg/Leq was 94.4 dB, indicating a reduction in sound level after clipping. Similarly, the pre-clipping time-weighted average noise level (TWA) was 1.2%, while the post-clipping TWA was 0.5%, indicating a decrease in exposure dose after clipping. In patient two, the average sound level for the post-clipping measurement (94.2 dB) was higher than the pre-clipping measurement (93.5 dB), but the difference was not statistically significant. These cases indicate the potential for using sound measurements as a reliable indicator of adequate aneurysm occlusion during clipping procedures. Further research is needed to confirm these findings.

Cost-Effectiveness of Forgoing Postoperative Catheter Angiography After Microsurgical Occlusion of Spinal Dorsal Intradural Arteriovenous Fistulas

OBJECTIVE

Spinal dorsal intradural arteriovenous fistulas (DI-AVFs) represent 70% of all spinal vascular lesions. Diagnostic tools include pre- and postoperative digital subtraction angiography (DSA) and intraoperative indocyanine green videoangiography (ICG-VA). ICG-VA has a high predictive value in DI-AVF occlusion, but postoperative DSA remains a core component of postoperative protocols. The aim of this study was to evaluate the potential cost reduction of forgoing postoperative DSA after microsurgical occlusion of DI-AVFs.

METHODS

Cohort-based cost effectiveness study of all DI-AVFs within a prospective, single-center cerebrovascular registry from January 1, 2017, to December 31, 2021.

RESULTS

Complete data including intraoperative ICG-VA and costs were available for 11 patients. Mean (SD) age was 61.5 (14.8) years. All DI-AVFs were treated with microsurgical clip ligation of the draining vein. ICG-VA showed complete obliteration in all patients. Postoperative DSA was performed for 6 patients and confirmed complete obliteration. Mean (SD) cost contributions for DSA and ICG-VA were $11,418 ($4,861) and $12 ($2), respectively. Mean (SD) total costs were $63,543 ($15,742) and $53,369 ($27,609) for patients who did and did not undergo postoperative DSA, respectively. Comorbidity status was identified as the main driver of total cost (P = 0.01 after adjusting for postoperative DSA status).

CONCLUSIONS

ICG-VA is a powerful diagnostic tool in demonstrating microsurgical cure of DI-AVFs, with a negative predictive value of 100%. Eliminating postoperative DSA in patients with confirmed DI-AVF obliteration on ICG-VA may yield substantial cost savings, in addition to sparing patients the risk and inconvenience of a potentially unnecessary invasive procedure.

Cost-effectiveness of repeat delayed imaging for spontaneous subarachnoid hemorrhage

BACKGROUND

In patients with intracranial aneurysm presenting with spontaneous subarachnoid hemorrhage (SAH), 15% of them could be missed by the initial diagnostic imaging. Repeat delayed imaging can help to identify previously undetected aneurysms, however, the cost-effectiveness of this strategy remains uncertain.

OBJECTIVE

The aim of this study is to assess the cost-effectiveness of repeat delayed imaging in patients with SAH who had a negative result during their initial imaging.

METHODS

A Markov model was developed to estimate the lifetime costs and quality-adjusted life-year (QALY) for patients who received or not received repeat delayed imaging. The analyses were conducted from a healthcare perspective, with costs reported in UK pounds and expressed in 2020 values. Extensive sensitivity analyses were performed to assess the robustness of the results.

RESULTS

The base case incremental cost-effectiveness ratio (ICER) of repeat delayed imaging is £9,314 per QALY compared to no-repeat delayed imaging. This ICER is below the National Institute for Health and Care Excellence (NICE) £20,000 per QALY willingness-to-pay threshold. At the NICE willingness-to-pay threshold of £20,000 per QALY, the probability that repeat delayed imaging is most cost-effective is 0.81. The results are sensitive to age, the utility of survived patients with a favorable outcome, the sensitivity of repeat delayed imaging, and the prevalence of aneurysm.

CONCLUSIONS

This study showed that, in the UK, it is cost-effective to provide repeat delayed imaging using computed tomographic angiography (CTA) for patients with SAH who had a negative result in their initial imaging.

Pre-stroke Physical Activity and Cerebral Collateral Circulation in Ischemic Stroke: A Potential Therapeutic Relationship?

Favorable cerebral collateral circulation contributes to hindering penumbral tissue from progressing to infarction and is associated with positive clinical outcomes after stroke. Given its clinical importance, improving cerebral collateral circulation is considered a therapeutic target to reduce burden after stroke. We provide a hypothesis-generating discussion on the potential association between pre-stroke physical activity and cerebral collateral circulation in ischemic stroke. The recruitment of cerebral collaterals in acute ischemic stroke may depend on anatomical variations, capacity of collateral vessels to vasodilate, and individual risk factors. Physical activity is associated with improved cerebral endothelial and vascular function related to vasodilation and angiogenic adaptations, and risk reduction in individual risk factors. More research is needed to understand association between cerebral collateral circulation and physical activity. A presentation of different methodological considerations for measuring cerebral collateral circulation and pre-stroke physical activity in the context of acute ischemic stroke is included. Opportunities for future research into cerebral collateral circulation, physical activity, and stroke recovery is presented.

Toward Alignment in the Reporting of Economic Evaluations of Diagnostic Tests and Biomarkers: The AGREEDT Checklist

Objectives. General frameworks for conducting and reporting health economic evaluations are available but not specific enough to cover the intricacies of the evaluation of diagnostic tests and biomarkers. Such evaluations are typically complex and model-based because tests primarily affect health outcomes indirectly and real-world data on health outcomes are often lacking. Moreover, not all aspects relevant to the evaluation of a diagnostic test may be known and explicitly considered for inclusion in the evaluation, leading to a loss of transparency and replicability. To address this challenge, this study aims to develop a comprehensive reporting checklist. Methods. This study consisted of 3 main steps: 1) the development of an initial checklist based on a scoping review, 2) review and critical appraisal of the initial checklist by 4 independent experts, and 3) development of a final checklist. Each item from the checklist is illustrated using an example from previous research. Results. The scoping review followed by critical review by the 4 experts resulted in a checklist containing 44 items, which ideally should be considered for inclusion in a model-based health economic evaluation. The extent to which these items were included or discussed in the studies identified in the scoping review varied substantially, with 14 items not being mentioned in ≥47 (75%) of the included studies. Conclusions. The reporting checklist developed in this study may contribute to improved transparency and completeness of model-based health economic evaluations of diagnostic tests and biomarkers. Use of this checklist is therefore encouraged to enhance the interpretation, comparability, and—indirectly—the validity of the results of such evaluations.

Clinical significance of changes in IL-6, CRP and S100in serum and NO in cerebrospinal fluid insubarachnoid hemorrhage and prognosis

Clinical significance of changes in interleukin-6 (IL-6), C-reactive protein (CRP) and S100 in serum and NO was investigated in cerebrospinal fluid (CSF) in subarachnoid hemorrhage (SAH) and its prognosis. A total of 43 SAH patients and 23 healthy subjects were selected and divided into cerebral vasospasm (CVS) group and non-CVS group, and favorable prognosis group and unfavorable prognosis group according to Hunt-Hess grade. The levels of IL-6, CRP, S100 and NO in CSF were detected, respectively, followed by statistical analysis of correlation. The higher the Hunt grade was, the higher the factor expression was; the expression levels of IL-6, CRP, S100 and NO in CSF were gradually increased in CVS group and unfavorable prognosis group, and the differences were significant compared with those in the control group. There was a positive correlation between the expression levels of each of the two factors among IL-6, CRP, S100 and NO in CSF, and the differences were statistically significant (P<0.05). The expression levels of IL-6, CRP, S100 and NO in CSF in SAH patients are significantly increased, showing positive correlations and participating in the occurrence and development of SAH, which provide new directions for the early clinical diagnosis of SAH.

Recurrent Bleeding After Perimesencephalic Hemorrhage

BACKGROUND

Perimesencephalic hemorrhage (PMH) is a type of subarachnoid hemorrhage with excellent long-term outcomes. Only 1 well-documented case of in-hospital rebleeding after PMH is described in the literature, which occurred after initiating antithrombotic treatment because of myocardial ischemia. We describe a patient with PMH without antithrombotic treatment who had 2 episodes of recurrent bleeding on the day of ictus. To validate the radiologic findings, we conducted a case-control study. Six neuroradiologists and 2 neuroradiology fellows performed a blinded assessment of serial unenhanced head computed tomography (CT) scans of 8 patients with a perimesencephalic bleeding pattern (1 index patient, 6 patients with PMH, 1 patient with perimesencephalic bleeding pattern and basilar artery aneurysm) to investigate a potential increase in amount of subarachnoid blood.

CASE DESCRIPTION

A 56-year-old woman with a perimesencephalic bleeding pattern and negative CT angiography had 2 episodes after the onset headache with a sudden increase of the headache. Blinded assessment of serial head CT scans of 8 patients with a perimesencephalic bleeding pattern identified the patient who was clinically suspected to have 2 episodes of recurrent bleeding to have an increased amount of subarachnoid blood on 2 subsequent CT scans.

CONCLUSIONS

Recurrent bleeding after PMH may also occur in patients not treated with antithrombotics. Even after early rebleeding, the prognosis of PMH is excellent.

Cost-Effectiveness of Angiographic Imaging in Isolated Perimesencephalic Subarachnoid Hemorrhage

Background and Purpose—

The purpose of this study is to perform a comprehensive cost-effectiveness analysis of all possible permutations of computed tomographic angiography (CTA) and digital subtraction angiography imaging strategies for both initial diagnosis and follow-up imaging in patients with perimesencephalic subarachnoid hemorrhage on noncontrast CT.

Methods—

Each possible imaging strategy was evaluated in a decision tree created with TreeAge Pro Suite 2014, with parameters derived from a meta-analysis of 40 studies and literature values. Base case and sensitivity analyses were performed to assess the cost-effectiveness of each strategy. A Monte Carlo simulation was conducted with distributional variables to evaluate the robustness of the optimal strategy.

Results—

The base case scenario showed performing initial CTA with no follow-up angiographic studies in patients with perimesencephalic subarachnoid hemorrhage to be the most cost-effective strategy ($5422/quality adjusted life year). Using a willingness-to-pay threshold of $50 000/quality adjusted life year, the most cost-effective strategy based on net monetary benefit is CTA with no follow-up when the sensitivity of initial CTA is >97.9%, and CTA with CTA follow-up otherwise. The Monte Carlo simulation reported CTA with no follow-up to be the optimal strategy at willingness-to-pay of $50 000 in 99.99% of the iterations. Digital subtraction angiography, whether at initial diagnosis or as part of follow-up imaging, is never the optimal strategy in our model.

Conclusions—

CTA without follow-up imaging is the optimal strategy for evaluation of patients with perimesencephalic subarachnoid hemorrhage when modern CT scanners and a strict definition of perimesencephalic subarachnoid hemorrhage are used. Digital subtraction angiography and follow-up imaging are not optimal as they carry complications and associated costs.

Benefit of a Sharp Computed Tomography Angiography Reconstruction Kernel for Improved Characterization of Intracranial Aneurysms

BACKGROUND:

Computed tomography angiography (CTA) is the first-line imaging modality used for cerebral aneurysms because of its speed and sensitivity for detection, although digital subtraction angiography is often required for more detailed aneurysm shape delineation.

OBJECTIVE:

To determine whether a sharper CTA reconstruction kernel can better characterize an aneurysm and improve decision-making before intervention.

METHODS:

Fifteen patients presenting with aneurysmal subarachnoid hemorrhage underwent 64-row CTA. CTA data were reconstructed using the default H20f smooth kernel and a H60f sharp kernel and compared with contemporaneous catheter 3-dimensional rotational angiography (3DRA). Aneurysm neck, width, and aspect ratio measurements were made using intensity line plots of identical projections on all imaging datasets and compared by matched-pair statistics.

RESULTS:

Aneurysm neck measurements from the H20f smooth kernel revealed overestimation compared with both the sharp kernel (greater by 0.64 ± 0.21 mm, P &lt; .01) and 3DRA (greater by 0.68 ± 0.19 mm, P &lt; .01). There was no statistically significant difference between 3DRA and the sharp kernel CTA measurements. Neck measurements correlated well between the H60f kernel and 3DRA but not between the H20f Kernel and 3DRA (R 0.97 vs 0.86).

CONCLUSION:

H60f sharp CTA kernel reconstruction provides more accurate anatomic characterization of cerebral aneurysms than the H20f smooth kernel at the expense of less visually pleasing reconstructions. Because it does not require additional contrast, radiation, or imaging hardware and is more similar to 3DRA, it may aid in selecting the appropriate treatment strategy before to evaluation by catheter-based angiography.