CTA-for-All: Impact of Emergency Computed Tomographic Angiography for All Patients With Stroke Presenting Within 24 Hours of Onset

Reducing Door-to-Puncture Times for Mechanical Thrombectomy in a Large Tertiary Hospital

Background and Objectives

Endovascular therapy (EVT) for stroke has emerged as an important therapy for selected stroke patients, and shorter times to clot removal improve functional outcomes. EVT requires the close coordination of multiple departments and poses unique challenges to care coordination in large hospitals. We present the results of our quality improvement project that aimed to improve our door-to-groin puncture (DTP) times for patients who undergo EVT after direct presentation to our emergency department.

Methods

We conducted time-motion studies to understand the full process of an EVT activation and conducted Gemba walks in multiple hospitals. We also reviewed the literature and interviewed stakeholders to create interventions that were implemented over 4 Plan-Do-Study-Act (PDSA) cycles. We retrospectively collected data starting from baseline and during every PDSA cycle. During each cycle, we studied the impact of the interventions, adjusted the interventions, and generated further interventions. A variety of interventions were introduced targeting all aspects of the EVT process. This included parallel processing to reduce waiting time, standardization of protocols and training of staff, behavioral prompts in the form of a stroke clock, and push systems to empower staff to facilitate the forward movement of the patient. A novel role-based communication app to facilitate group communications was also used.

Results

Eighty-eight patients spanning across 22 months were analyzed. After the final PDSA cycle, the median DTP time was reduced by 36.5% compared with baseline (130 minutes (interquartile range [IQR] 111-140) to 82.5 minutes (IQR 74.8-100)). There were improvements in all phases of the EVT process with the largest time savings occurring in EVT decision to patient arrival at the angiosuite. Interventions that were most impactful are described.

Discussion

EVT is a complex process involving multiple processes and local factors. Analysis of the process from all angles and intervening on multiple small aspects can add up to significant improvements in DTP times.

Longitudinal changes in the US emergency department use of advanced neuroimaging in the mechanical thrombectomy era

PURPOSE

To describe ED neuroimaging trends across the time-period spanning the early adoption of endovascular therapy for acute stroke (2013-2018).

MATERIALS AND METHODS

We performed a retrospective, cross-sectional study of ED visits using the 2013-2018 National Emergency Department Sample, a 20% sample of ED encounters in the United States. Neuroimaging use was determined by Common Procedural Terminology (CPT) code for non-contrast head CT (NCCT), CT angiography head (CTA), CT perfusion (CTP), and MRI brain (MRI) in non-admitted ED patients. Data was analyzed according to sampling weights and imaging rates were calculated per 100,000 ED visits. Multivariate logistic regression analysis was performed to identify hospital-level factors associated with imaging utilization.

RESULTS

Study population comprised 571,935,906 weighted adult ED encounters. Image utilization increased between 2013 and 2018 for all modalities studied, although more pronounced in CTA (80.24/100,000 ED visits to 448.26/100,000 ED visits (p < 0.001)) and CTP (1.75/100,000 ED visits to 28.04/100,000 ED visits p < 0.001)). Regression analysis revealed that teaching hospitals were associated with higher odds of high CTA utilization (OR 1.88 for 2018, p < 0.05), while low-volume EDs and public hospitals showed the reverse (OR 0.39 in 2018, p < 0.05).

CONCLUSIONS

We identified substantial increases in overall neuroimaging use in a national sample of non-admitted emergency department encounters between 2013 and 2018 with variability in utilization according to both patient and hospital properties. Further investigation into the appropriateness of this imaging is required to ensure that access to acute stroke treatment is balanced against the timing and cost of over-imaging.

Upfront vascular imaging in acute stroke: Impact on thrombectomy transfer time at a primary stroke center

OBJECTIVES

Early cerebral arterial imaging is currently only recommended in the subgroup of acute ischemic stroke (AIS) patients suspected of having large vessel occlusion (LVO). There is limited data on the impact of early cerebrovascular imaging in all suspected AIS patients presenting within 24 h of symptom onset and the impact on door in-door out (DIDO) time.

MATERIALS AND METHODS

In January 2020, our Primary Stroke Center implemented a protocol to perform upfront head and neck CT angiography (CTA) with initial non-contrast CT head for all suspected ischemic stroke patients screening positive for BE-FAST stroke symptoms within 24 h from last known normal time. We retrospectively reviewed IV alteplase and thrombectomy-eligible patients before (January 1-December 31, 2019) and after protocol implementation (January 1, 2020-June 30, 2022).

RESULTS

Of 86 patients meeting study criteria, up-front CTA was associated with significant reductions in door-to-CTA start (median 37 vs 15 min, p = 0.003), door-to-CTA result (median 83 vs 52 min, p = 0.023) and DIDO times (median 150 vs 106 min, p = 0.023). There was no significant difference in door-to-needle time before and after protocol implementation (median 48 vs 43 min, p = 0.450).

CONCLUSION

Up-front cerebrovascular imaging with CTA in suspected AIS patients presenting within 24 h resulted in shorter DIDO times without delaying door-to-needle times. Primary Stroke Centers should consider this approach to detect LVO early and expedite patient transport to thrombectomy capable centers.

Deep learning-assisted diagnosis of large vessel occlusion in acute ischemic stroke based on four-dimensional computed tomography angiography

Purpose

To develop deep learning models based on four-dimensional computed tomography angiography (4D-CTA) images for automatic detection of large vessel occlusion (LVO) in the anterior circulation that cause acute ischemic stroke.

Methods

This retrospective study included 104 LVO patients and 105 non-LVO patients for deep learning models development. Another 30 LVO patients and 31 non-LVO patients formed the time-independent validation set. Four phases of 4D-CTA (arterial phase P1, arterial-venous phase P2, venous phase P3 and late venous phase P4) were arranged and combined and two input methods was used: combined input and superimposed input. Totally 26 models were constructed using a modified HRNet network. Assessment metrics included the areas under the curve (AUC), accuracy, sensitivity, specificity and F1 score. Kappa analysis was performed to assess inter-rater agreement between the best model and radiologists of different seniority.

Results

The P1 + P2 model (combined input) had the best diagnostic performance. In the internal validation set, the AUC was 0.975 (95%CI: 0.878-0.999), accuracy was 0.911, sensitivity was 0.889, specificity was 0.944, and the F1 score was 0.909. In the time-independent validation set, the model demonstrated consistently high performance with an AUC of 0.942 (95%CI: 0.851-0.986), accuracy of 0.902, sensitivity of 0.867, specificity of 0.935, and an F1 score of 0.901. The best model showed strong consistency with the diagnostic efficacy of three radiologists of different seniority (k = 0.84, 0.80, 0.70, respectively).

Conclusion

The deep learning model, using combined arterial and arterial-venous phase, was highly effective in detecting LVO, alerting radiologists to speed up the diagnosis.

Diagnostic Imaging Utilization in the Emergency Department: Recent Trends in Volume and Radiology Work Relative Value Units

PURPOSE

The aim of this study was to quantify and characterize the recent trend in emergency department (ED) imaging volumes and radiology work relative value units (wRVUs) at level I and level III trauma centers.

METHODS

Total annual diagnostic radiology imaging volumes and wRVUs were obtained from level I and level III trauma centers from January 2014 to December 2021. Imaging volumes were analyzed by modality type, examination code, and location. Total annual patient ED encounters (EDEs), annual weighted Emergency Severity Index, and patient admissions from the ED were obtained. Data were analyzed using annual imaging volume or wRVUs per EDE, and percentage change was calculated.

RESULTS

At the level I trauma center, imaging volumes per EDE increased for chest radiography (5.5%), CT (35.5%), and MRI (56.3%) and decreased for ultrasound (-5.9%) from 2014 to 2021. Imaging volumes per EDE increased for ultrasound (10.4%), CT (74.6%), and MRI (2.0%) and decreased for chest radiography (-4.4%) at the level III trauma center over the same 8-year period. Total wRVUs per EDE increased at both the level I (34.9%) and level III (76.6%) trauma centers over the study period.

CONCLUSIONS

ED imaging utilization increased over the 8-year study period at both level I and level III trauma centers, with an increase in total wRVUs per EDE. There was a disproportionate increased utilization of advanced imaging, such as CT, over time. ED utilization trends suggest that there will be a continued increase in demand for advanced imaging interpretation, including at lower acuity hospitals, so radiology departments should prepare for this increased work demand.

The diagnostic tests and functional outcomes of acute ischemic stroke or transient ischemic attack in young adults: A 4-year hospital-based observational study

BACKGROUND AND OBJECTIVES

Ischemic strokes in young adults have been a significant concern due to various potential etiologies and had substantial clinical and public health impacts. We aimed to study the diagnostic tests, etiologies, and functional outcomes of acute ischemic stroke (AIS) and transient ischemic attack (TIA) in young adult patients.

METHODS

The data were retrieved from the Chiang Mai University Hospital Stroke Registry between January 2018 and December 2021. Consecutive AIS or TIA patients were included if they were 18-50 years and had no stroke mimics. Study outcomes were proportions of positive diagnostic tests, and 90-day modified Rankin Scale (mRS).

RESULTS

Of 244 enrolled patients, 59.0% (n = 144) were male, and 38.1% (n = 93) were aged 18-40, classified as the younger age group. There was a high incidence of diabetes (24.5%) and dyslipidemia (54.3%) among patients aged 41-50, associated with small-vessel occlusion and large-artery atherosclerosis stroke classification in this age group. Patients aged 18-40 years had more other determined etiologies (39.8%), with hypercoagulability (8.2%), arterial dissection (7.8%), and cardiac sources (6.6%) being the first three causes, which were associated with higher anticoagulant treatment. The cerebrovascular study, cardiac evaluation using echocardiography, and antiphospholipid syndrome testing were commonly performed, of which computed tomography angiography provided a high proportion of positive results (80.3%). 76.3% of young adult patients had excellent functional outcomes (mRS 0-1) with a median mRS of 0 (interquartile range 0-1) at 90-day follow-up.

CONCLUSIONS

Stroke of other determined etiology remained the common cause of stroke in young adults, and most affected individuals had excellent clinical outcomes. Blood tests for arterial hypercoagulability and noninvasive vascular and cardiac evaluations are encouraged in selected patients to determine the stroke etiology and guide for appropriate preventive strategies.

Effect of Radiographic Contrast Media Shortage on Stroke Evaluation in the United States

BACKGROUND AND PURPOSE

We performed this study to identify the effect of the nationwide iodinated contrast media shortage due to reduction in GE Healthcare production, initiated on April 19, 2022, on the evaluation of patients with stroke.

MATERIALS AND METHODS

We analyzed the data on 72,514 patients who underwent imaging processed with commercial software in a sample of 399 hospitals in United States from February 28, 2022, through July 10, 2022. We quantified the percentage change in the daily number of CTAs and CTPs performed before and after April 19, 2022.

RESULTS

The daily counts of individual patients who underwent CTAs decreased (a 9.6% reduction, P = .002) from 1.584 studies per day per hospital to 1.433 studies per day per hospital. The daily counts of individual patients who underwent CTPs decreased (a 25.9% reduction, P = .003) from 0.484 studies per day per hospital to 0.358 studies per day per hospital. A significant reduction in CTPs using GE Healthcare contrast media (43.06%, P < .001) was seen but not in CTPs using non-GE Healthcare contrast media (increase by 2.93%, P = .29). The daily counts of individual patients with large-vessel occlusion decreased (a 7.69% reduction) from 0.124 per day per hospital to 0.114 per day per hospital.

CONCLUSIONS

Our analysis reported changes in the use of CTA and CTP in patients with acute ischemic stroke during the contrast media shortage. Further research needs to identify effective strategies to reduce the reliance on contrast media-based studies such as CTA and CTP without compromising patient outcomes.

Malpractice Lawsuits Relating to Mechanical Thrombectomy for Acute Ischemic Stroke: A Systematic Review

Background and Purpose

Medical-legal claims for malpractice relating to the use of alteplase for acute ischemic stroke (AIS) are usually for failure to treat rather than for complications. The advent of mechanical thrombectomy (MT) as a standard of AIS treatment has added a new dimension to the medical-legal landscape as there is a need for the delivery of a higher level of care creating the potential for delays and errors associated with such treatment. Information on causes of malpractice related to mechanical thrombectomy (MT) is currently lacking.

Methods

We conducted a systematic review of legal databases (Westlaw, LexisNexis, Google Scholar Case Law, and VerdictSearch) to identify medical malpractice cases with and without verdicts filed in the United States up to March 31, 2021 which pertained to performance or non-performance of MT for AIS. We collected various case characteristics, case outcomes, and root causes for malpractice claims.

Results

We found 25 cases, 16 of which alleged failure to treat with MT, 8 for harm due to delay in treatment and 1 case that alleged complications. Root causes included delay in vascular imaging, communication breakdowns, and transportation delays. Eight cases had an outcome in favor of the defendant, 9 in favor of the plaintiff, and 8 remained to be determined.

Conclusions

As with alteplase, malpractice allegations regarding MT for AIS are largely for failure to treat or delay in treatment as opposed to complications. Addressing root causes of diagnostic delay, communication breakdowns, and transportation delays may reduce subsequent malpractice risk.

Diagnostic accuracy of a decision-support software for the detection of intracranial large-vessel occlusion in CT angiography

AIM

To investigate the real-world clinical performance of the decision-support software "e-CTA" (e-Stroke Suite, Brainomix Limited, Oxford UK) for the detection of acute intracranial large-vessel occlusion (LVO) on computed tomography (CT) angiography at a UK district general hospital.

MATERIALS AND METHODS

The retrospective study included 300 consecutive CT angiograms of the head and neck performed between 8 March 2021 and 20 May 2021. e-CTA findings were recorded and compared with the radiologist report. Cases in which there was disagreement between e-CTA and the radiologist were reviewed by a sub-specialist vascular radiologist as the reference standard.

RESULTS

The incidence of intracranial LVO was 7%. e-CTA correctly identified 18 of 21 intracranial proximal LVOs (86%). There were 34 false positives. The sensitivity was 0.86 (95% confidence interval [CI], 0.64-0.97), with specificity of 0.88 (95% CI, 0.83-0.91). The positive predictive value was 0.35 (95% CI, 0.27-0.43). The negative predictive value was 0.99 (95% CI, 0.96-1.00).

CONCLUSION

Sensitivity, specificity, and negative predictive values were similar to those reported in the literature (Seker et al., Int J Stroke. 2021; 17:77-82); however, the positive predictive value for e-CTA was significantly lower. In practice, this meant that over half of all reported occlusions by the software were false positives. Radiologists should be aware of these metrics in order to assign appropriate weight to software findings when formulating a report. Differences in population demographics, scanners, CT protocols, and incidence are all factors potentially influencing software accuracy. Local validation testing may help provide accuracy metrics more relevant to individual institutions.

Recommendations on the use of computed tomography in the stroke code: Consensus document SENR, SERAU, GEECV-SEN, SERAM

The Spanish Society of Emergency Radiology (SERAU), the Spanish Society of Neuroradiology (SENR), the Spanish Society of Neurology through its Cerebrovascular Diseases Study Group (GEECV-SEN) and the Spanish Society of Medical Radiology (SERAM) have met to draft this consensus document that will review the use of computed tomography in the stroke code patients, focusing on its indications, the technique for its correct acquisition and the possible interpretation mistakes.

State-of-the-art CT and MR imaging and assessment of atherosclerotic carotid artery disease: standardization of scanning protocols and measurements-a consensus document by the European Society of Cardiovascular Radiology (ESCR)

The European Society of Cardiovascular Radiology (ESCR) is the European specialist society of cardiac and vascular imaging. This society's highest priority is the continuous improvement, development, and standardization of education, training, and best medical practice, based on experience and evidence. The present intra-society consensus is based on the existing scientific evidence and on the individual experience of the members of the ESCR writing group on carotid diseases, the members of the ESCR guidelines committee, and the members of the executive committee of the ESCR. The recommendations published herein reflect the evidence-based society opinion of ESCR. We have produced a twin-papers consensus, indicated through the documents as respectively "Part I" and "Part II." The first document (Part I) begins with a discussion of features, role, indications, and evidence for CT and MR imaging-based diagnosis of carotid artery disease for risk stratification and prediction of stroke (Section I). It then provides an extensive overview and insight into imaging-derived biomarkers and their potential use in risk stratification (Section II). Finally, detailed recommendations about optimized imaging technique and imaging strategies are summarized (Section III). The second part of this consensus paper (Part II) is focused on structured reporting of carotid imaging studies with CT/MR. KEY POINTS: • CT and MR imaging-based evaluation of carotid artery disease provides essential information for risk stratification and prediction of stroke. • Imaging-derived biomarkers and their potential use in risk stratification are evolving; their correct interpretation and use in clinical practice must be well-understood. • A correct imaging strategy and scan protocol will produce the best possible results for disease evaluation.

Acute Neurointervention for Ischemic Stroke

Acute ischemic stroke (AIS) is one of the major causes of death worldwide and a leading cause of disability. Until recently treatment of AIS was supportive, and in a minority of patients intravenous thrombolysis was available but with marginal clinical benefit. With the advent of stent retrievers, distal aspiration catheters as well as improved patient selection neurologic outcomes have greatly improved. However, the care of patients with AIS is still challenging and requires the early recognition of stroke symptoms, extensive diagnostic testing, early intervention, and advanced nursing and critical care.

Practice enhancements with FastStroke ColorViz analysis in acute ischemic stroke

In acute ischemic stroke (AIS), large vessel occlusion (LVO) and the status of pial collaterals are important factors in decision-making for further treatment such as endovascular therapy. Multiphasic CT Angiogram (mCTA) is the mainstay of AIS imaging, allowing detection of LVO, evaluation of intracranial arterial dynamics, and quantification of pial collaterals. However, thorough mCTA evaluation entails scrutiny of multiple image datasets, individually and then simultaneously, which can be time-consuming, causing a potential delay in treatment. ColorViz (FastStroke, GE Healthcare, Milwaukee, Wisconsin) is a novel CT application which combines mCTA information into a single color-coded dataset for quick, unequivocal evaluation of pial collaterals. In our practice, ColorViz is both time-saving and increases the diagnostic accuracy of LVO and pial collaterals as well as medium vessel, multivessel and posterior circulation occlusions. In this article, we discuss the practical aspects of ColorViz in patients presenting with AIS.

Hyperdense Artery Sign in Patients With Acute Ischemic Stroke-Automated Detection With Artificial Intelligence-Driven Software

Background

Hyperdense artery sign (HAS) on non-contrast CT (NCCT) can indicate a large vessel occlusion (LVO) in patients with acute ischemic stroke. HAS detection belongs to routine reporting in patients with acute stroke and can help to identify patients in whom LVO is not initially suspected. We sought to evaluate automated HAS detection by commercial software and compared its performance to that of trained physicians against a reference standard.

Methods

Non-contrast CT scans from 154 patients with and without LVO proven by CT angiography (CTA) were independently rated for HAS by two blinded neuroradiologists and an AI-driven algorithm (Brainomix®). Sensitivity and specificity were analyzed for the clinicians and the software. As a secondary analysis, the clot length was automatically calculated by the software and compared with the length manually outlined on CTA images as the reference standard.

Results

Among 154 patients, 84 (54.5%) had CTA-proven LVO. HAS on the correct side was detected with a sensitivity and specificity of 0.77 (CI:0.66–0.85) and 0.87 (0.77–0.94), 0.8 (0.69–0.88) and 0.97 (0.89–0.99), and 0.93 (0.84–0.97) and 0.71 (0.59–0.81) by the software and readers 1 and 2, respectively. The automated estimation of the thrombus length was in moderate agreement with the CTA-based reference standard [intraclass correlation coefficient (ICC) 0.73].

Conclusion

Automated detection of HAS and estimation of thrombus length on NCCT by the tested software is feasible with a sensitivity and specificity comparable to that of trained neuroradiologists.

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.

Rapid Identification of Patients Eligible for Direct Emergent Computed Tomography Angiography during Acute Ischemic Stroke: The DARE-PACE Assessment

Background: We investigated the clinical signs to establish a method for rapid identification of patients with the National Institute of Health Stroke Scale (NIHSS) score ≥ 8 eligible for direct brain CTA study; Methods: We retrospectively enrolled 2895 in patients with acute ischemic stroke (AIS). Four items in the NIHSS were selected as the main clinical signs of stroke; Results: A total of 922 (31.8%) patients had an initial NIHSS score of ≥8. The average door-to-CT time and door-to-CTA time were 13.4 ± 1.8 and 75.5 ± 44.5 min, respectively. Among 658 patients who had the priority signs, namely dense hemiplegia (D), aphasia with right arm drop (AR), and eyeball forced deviation (E), 634 patients (96.4%) with an NIHSS score ≥ 8 were identified. By using a classification and regression tree analysis, 153 patients with an NIHSS ≥ 8 were identified among 175 patients (87.4%) who had the secondary signs, namely hemiparesis with limb falls (P), aphasia (A), drowsy or worse consciousness (C), and eyeball limitation (E). The sensitivity, specificity, and accuracy were 85.4%, 97.7%, and 95.3%, respectively. Conclusions: The DARE-PACE assessment involving a checkbox list provides excellent accuracy for rapid identification of AIS patients with an NIHSS score ≥ 8 for direct CTA study to reduce the time delay for endovascular thrombectomy.

Acute ischemic stroke or migraine with aura? Triage considerations

ABSTRACT

This article discusses the complex relationship between acute ischemic stroke and migraine with aura, and critical nursing interventions.

Acute Ischemic Stroke With Mild Symptoms-To Thrombolyse or Not to Thrombolyse?

Management of stroke with minor symptoms may represent a therapeutical dilemma as the hemorrhage risk of acute thrombolytic therapy may eventually outweigh the stroke severity. However, around 30% of patients presenting with minor stroke symptoms are ultimately left with disability. The objective of this review is to evaluate the current literature and evidence regarding the management of minor stroke, with a particular emphasis on the role of IV thrombolysis. Definition of minor stroke, pre-hospital recognition of minor stroke and stroke of unknown onset are discussed together with neuroimaging aspects and existing evidence for IV thrombolysis in minor strokes. Though current guidelines advise against the use of thrombolysis in those without clearly disabling symptoms due to a paucity of evidence, advanced imaging techniques may be able to identify those likely to benefit. Further research on this topic is ongoing.

Fibromuscular Dysplasia/Carotid Web in Angio-CT Imaging: A Rare Cause of Ischemic Stroke

Background and Objectives: Carotid web (CaW) is an intimal variant of fibromuscular dysplasia and may constitute as one of rare causes of acute ischemic stroke (AIS). The objective of this study was to determine the prevalence of CaW in patients with AIS or transient ischemic attack (TIA) based on head/neck CT angiography (CTA) in a Polish cohort study. Materials and Methods: A retrospective study was performed by analyzing 1480 electronic clinical and imaging data regarding patients with AIS or TIA, hospitalized in the years 2018–2020 in the authors’ institution. The final sample consisted of 181 patients who underwent head/neck CTA; aged 67.81 ± 13.51 years (52% were women). All head/neck CTA studies were independently evaluated by two radiologists. The patient’s clinical condition was assessed with the National Institutes of Health Stroke Scale (NIHSS, 5.76 ± 4.05 and 2.88 ± 3.38 at admission and at discharge, respectively). Results: 27 patients were identified with CaW. The prevalence of CaW in the final sample (181 pts with good quality CTA) was 14.9%. In the CaW group, 89% patients had AIS, including 26% diagnosed with recurrent and 11% with cryptogenic strokes. There were no significant differences between the presence of CaW and gender, age, NIHSS score, recurrent or cryptogenic stroke. Conclusions: Our study demonstrated that CaW may be an underrecognized entity leading to cerebrovascular events. The diagnosis of CaW depends on a high level of awareness and a comprehensive analysis of the neuroimaging studies. Our findings support the hypothesis that it is worthwhile to perform CTA to determine the etiology of ischemic stroke, particularly if predicting factors were not identified.

Squamous Cell Carcinoma of the Neck: An Unlikely Stroke Mimic

BACKGROUND

Stroke mimics are noncerebrovascular conditions that present with classical stroke symptoms. They account for up to 30% of stroke presentations in the emergency department (ED). Emergency physicians are faced with a diagnostic dilemma-rapid treatment of stroke, a leading cause or mortality and morbidity in the United States, or ruling out the ever-growing list of conditions that mimic strokes.

CASE REPORT

An 87-year-old man with a 60-year smoking history, chronic obstructive pulmonary disease, and extensive cardiovascular disease history presented to the ED with a chief symptom of new onset right-arm weakness. Computed tomography (CT) excluded hemorrhage and lesions, and additional CT angiography imaging revealed a large mass compressing the right subclavian artery. Given the initial workup, mass effect on the right brachial plexus better explained the patient's symptoms. Two weeks later, a CT scan of the chest, abdomen, and pelvis revealed masses on the pubic ramus, iliac bone, and several vertebral bodies. Biopsy of the rib mass revealed squamous cell carcinoma. The patient was diagnosed with bone metastasis of unknown origin and started on radiation therapy. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Even in fast-paced settings, clinicians must maintain a high level of suspicion for stroke mimics. This case illustrates the vital importance of neuroimaging in the diagnosis of stroke mimics and discusses clinical characteristics and patient risk factors that increase the likelihood of a stroke mimic diagnosis, serving as a tool for physicians facing this diagnostic dilemma.

Door-In-Door-Out Process Times at Primary Stroke Centers in Chicago

STUDY OBJECTIVE

Acute stroke patients often require interfacility transfer from primary stroke centers to comprehensive stroke centers. Given the time-sensitive benefits of endovascular reperfusion, reducing door-in-door-out time at the primary stroke center is a target for quality improvement. We sought to identify modifiable predictors of door-in-door-out times at 3 Chicago-region primary stroke centers.

METHODS

We performed a retrospective analysis of consecutive patients with acute stroke from February 1, 2018 to January 31, 2020 who required transfer from 1 of 3 primary stroke centers to 1 of 3 affiliated comprehensive stroke centers in the Chicago region. Stroke coordinators at each primary stroke center abstracted data on type of transport, medical interventions and treatments prior to transfer, and relevant time intervals from patient arrival to departure. We evaluated predictors of door-in-door-out time using median regression models.

RESULTS

Of 191 total patients, 67.9% arrived by emergency medical services and 57.4% during off-hours. Telestroke was performed in 84.2%, 30.5% received alteplase, and 48.4% underwent a computed tomography (CT) angiography at the primary stroke center. The median door-in-door-out time was 148.5 (interquartile range 106 to 207.8) minutes. The largest contributors to door-in-door-out time, in minutes, were CT to CT angiography time (22 [7 to 73.5]), transfer center contact to ambulance request time (20 [8 to 53.3]), ambulance request to arrival time (20.5 [14 to 36]), and transfer ambulance time at primary stroke center (26 [21 to 35]). Factors associated with door-in-door-out time were (adjusted median differences, in minutes [95% confidence intervals]): CT angiography performed at primary stroke center (+39 [12.3 to 65.7]), walk-in arrival mode (+53 [4.1 to 101.9]), administration of intravenous alteplase (-29 [-31.3 to -26.7]), intubation at primary stroke center (+23 [7.3 to 38.7]), and ambulance request by primary stroke center (-20 [-34.3 to -5.7]).

CONCLUSION

Door-in-door-out times at Chicago-area primary stroke centers average nearly 150 minutes. Reducing time to CT angiography, receipt of alteplase, and ambulance request are likely important modifiable targets for interventions to decrease door-in-door-out times at primary stroke centers.

Controversies in Imaging of Patients with Acute Ischemic Stroke: AJR Expert Panel Narrative Review

The development of reperfusion therapies has profoundly impacted stroke care, initially with the advent of IV thrombolytic (IVT) treatment and, more recently, with the development and refinement of endovascular treatment (EVT). Progress in neuroimaging has supported the paradigm shift of stroke care, and advanced neuroimaging now has a fundamental role in triaging patients for both IVT and EVT. As the standard of care for acute ischemic stroke (AIS) evolves, controversies remain in certain clinical scenarios. This article explores the use of multimodality imaging for treatment selection of AIS in the context of recent guidelines, highlighting controversial topics and providing guidance for clinical practice. Results of major randomized trials supporting EVT are reviewed. Advantages and disadvantages of CT, CTA, MRI, and MRA in stroke diagnosis are summarized, with attention to level 1 evidence supporting the role of vascular imaging and perfusion imaging. Patient selection is compared between approaches based on time thresholds and physiologic approaches based on infarct core measurement using imaging. Moreover, various imaging approaches to core measurement are described. As ongoing studies push treatment boundaries, advanced imaging is expected to help identify a widening range of patients who may benefit from therapy.

Triage of Patients with Intracerebral Hemorrhage to Comprehensive Versus Primary Stroke Centers

OBJECTIVES

The management of patients admitted with intracerebral hemorrhage (ICH) mostly occurs in an ICU. While guidelines recommend initial treatment of these patients in a neurocritical care or stroke unit, there is limited data on which patients would benefit most from transfer to a comprehensive stroke center where on-site neurosurgical coverage is available 24/7. As neurocritical units become more common in primary stroke centers, it is important to determine which patients are most likely to require neurosurgical intervention and transfer to comprehensive stroke centers.

MATERIALS AND METHODS

This is a retrospective observational cohort study conducted at an academic comprehensive stroke center in the United States. Four-hundred-fifty-nine consecutive patients transferred or directly admitted to the neurocritical care unit from 2016-2018 with the primary diagnosis of ICH were included. Univariate statistics and multivariate regression were used to identify clinical characteristics associated with neurosurgical intervention, defined as undergoing craniotomy, ventriculostomy, or endovascular embolization of an arteriovenous malformation (AVM).

RESULTS

The following variables were associated with neurosurgical intervention in multivariate analysis: age (OR 0.38, 95% CI 0.27-0.55), admission Glasgow Coma Scale (OR 0.29, 95% CI 0.18-0.48), the presence of intraventricular hemorrhage (OR 2.82, CI 1.71-4.65), infratentorial location of ICH (OR 2.28, 95% CI 1.20-4.31), previous antiplatelet use (OR 2.04, 95% CI 1.24-3.34), and an AVM indicated on CT Angiogram (OR 2.59, 95% CI 1.19-5.63) were independently associated with the need for neurosurgical intervention. This was translated into a scoring system to help make quick triage decisions, with high sensitivity (99%, 95% CI 97-99%) and negative predictive value (98%, 95% CI 89-99%).

CONCLUSIONS

Using previously well described predictors of severity in ICH patients, we were able to develop a scoring system to predict the need for neurosurgical intervention with high sensitivity and negative predictive value.

Variability of computed tomography angiography coverage of lung parenchyma in acute stroke

BACKGROUND

Computed tomography angiography (CTA) of the head and neck during acute ischemic stroke (AIS) usually includes visualization of lung apices. The possibility to evaluate for pulmonary changes, e.g. peripheral ground-glass and consolidative opacities suggestive of coronavirus disease 2019 (COVID-19)-related pneumonia, depends on the area of the lung covered by CTA.

METHODS

We performed an analysis of a real-world scenario assessing the variability of lung coverage on CTA in patients presenting with AIS to a comprehensive stroke center (CSC) or to one of eight primary stroke centers (PSC) within a teleradiological network covered by the comprehensive stroke center in 2019.

RESULTS

Our final analysis included n = 940 CTA, and in n = 573 (61%) merely lung apices were covered. In 19/940 (2%) of patients no lung tissue was covered by CTA. CTA scanning protocols in the CSC began significantly more frequently at the level of the ascending aorta (CSC: n = 180 (38.2%), PSC: n = 127 (27.1%), p-value < 0.001) and the aortic arch (CSC: n = 140 (29.7%), PSC: n = 83 (17.7%), p-value < 0.001), and by this covered less frequently the lower lobes compared to CTA acquired in one of the PSC.

CONCLUSIONS

In our pre-COVID-19 pandemic representative stroke patient cohort, CTA for AIS covered most often only lung apices. In 37% of the patients CTA visualized at least parts of the lower lobes, the lingula or the middle lobe allowing for a more extensive assessment of the lungs.

CTA Protocols in a Telestroke Network Improve Efficiency for Both Spoke and Hub Hospitals

BACKGROUND AND PURPOSE

Telestroke networks support screening for patients with emergent large-vessel occlusions who are eligible for endovascular thrombectomy. Ideal triage processes within telestroke networks remain uncertain. We characterize the impact of implementing a routine spoke hospital CTA protocol in our integrated telestroke network on transfer and thrombectomy patterns.

MATERIALS AND METHODS

A protocol-driven CTA process was introduced at 22 spoke hospitals in November 2017. We retrospectively identified prospectively collected patients who presented to a spoke hospital with National Institutes of Health Stroke Scale scores ≥6 between March 1, 2016 and March 1, 2017 (pre-CTA), and March 1, 2018 and March 1, 2019 (post-CTA). We describe the demographics, CTA utilization, spoke hospital retention rates, emergent large-vessel occlusion identification, and rates of endovascular thrombectomy.

RESULTS

There were 167 patients pre-CTA and 207 post-CTA. The rate of CTA at spoke hospitals increased from 15% to 70% (P < .001). Despite increased endovascular thrombectomy screening in the extended window, the overall rates of transfer out of spoke hospitals remained similar (56% versus 54%; P = .83). There was a nonsignificant increase in transfers to our hub hospital for endovascular thrombectomy (26% versus 35%; P = .12), but patients transferred >4.5 hours from last known well increased nearly 5-fold (7% versus 34%; P < .001). The rate of endovascular thrombectomy performed on patients transferred for possible endovascular thrombectomy more than doubled (22% versus 47%; P = .011).

CONCLUSIONS

Implementation of CTA at spoke hospitals in our telestroke network was feasible and improved the efficiency of stroke triage. Rates of patients retained at spoke hospitals remained stable despite higher numbers of patients screened. Emergent large-vessel occlusion confirmation at the spoke hospital lead to a more than 2-fold increase in thrombectomy rates among transferred patients at the hub.

Diagnostic performance of single-phase CT angiography in detecting large vessel occlusion in ischemic stroke: A systematic review

PURPOSE

To systematically review the diagnostic performance of single-phase CT angiography (CTA) in detecting intracranial large vessel occlusion (LVO).

METHOD

MEDLINE and Embase were searched for studies investigating the diagnostic performance of single-phase CTA in detecting LVO. Study quality was assessed. Sensitivity and specificity were calculated and meta-analyzed with a bivariate random-effects model. Heterogeneity was assessed with a chi-squared test.

RESULTS

Eleven studies were included. High risk of bias with regard to "patient selection", "reference standard", and "flow and timing" was present in 4, 1, and 2 studies, respectively. In 7 studies, it was unclear whether reference tests were interpreted blinded to CTA readings. There was variability in types of vessel segments analyzed, resulting in heterogeneous sensitivity and specificity (P < 0.05). Two studies provided data for the proximal anterior circulation (distal intracranial carotid artery, A1-, A2-, M1- and M2-segments), with pooled sensitivity of 88.4 % (95 % CI: 62.2-97.2 %) and pooled specificity of 98.5 % (95 % CI: 33.2-100 %). One study suggested that multiphase CTA improved agreement between nonexperts and an expert in detecting A1-, A2-, M1-, M2-, and M3-segment occlusions compared to single-phase CTA (ĸ = 0.72-0.76 vs. ĸ = 0.32-0.45). No other included study reported added value of advanced CTA (CT perfusion, 4D-CTA, or multiphase CTA) compared to single-phase CTA in detecting proximal anterior circulation LVO.

CONCLUSION

There is lack of high-quality studies on the diagnostic performance of single-phase CTA for LVO detection in the proximal anterior circulation. The added value of advanced CTA techniques in detecting proximal anterior circulation LVO is not completely clear yet.

Detecting Large Vessel Occlusion at Multiphase CT Angiography by Using a Deep Convolutional Neural Network

Background Large vessel occlusion (LVO) stroke is one of the most time-sensitive diagnoses in medicine and requires emergent endovascular therapy to reduce morbidity and mortality. Leveraging recent advances in deep learning may facilitate rapid detection and reduce time to treatment. Purpose To develop a convolutional neural network to detect LVOs at multiphase CT angiography. Materials and Methods This multicenter retrospective study evaluated 540 adults with CT angiography examinations for suspected acute ischemic stroke from February 2017 to June 2018. Examinations positive for LVO (n = 270) were confirmed by catheter angiography and LVO-negative examinations (n = 270) were confirmed through review of clinical and radiology reports. Preprocessing of the CT angiography examinations included vasculature segmentation and the creation of maximum intensity projection images to emphasize the contrast agent-enhanced vasculature. Seven experiments were performed by using combinations of the three phases (arterial, phase 1; peak venous, phase 2; and late venous, phase 3) of the CT angiography. Model performance was evaluated on the held-out test set. Metrics included area under the receiver operating characteristic curve (AUC), sensitivity, and specificity. Results The test set included 62 patients (mean age, 69.5 years; 48% women). Single-phase CT angiography achieved an AUC of 0.74 (95% confidence interval [CI]: 0.63, 0.85) with sensitivity of 77% (24 of 31; 95% CI: 59%, 89%) and specificity of 71% (22 of 31; 95% CI: 53%, 84%). Phases 1, 2, and 3 together achieved an AUC of 0.89 (95% CI: 0.81, 0.96), sensitivity of 100% (31 of 31; 95% CI: 99%, 100%), and specificity of 77% (24 of 31; 95% CI: 59%, 89%), a statistically significant improvement relative to single-phase CT angiography (P = .01). Likewise, phases 1 and 3 and phases 2 and 3 also demonstrated improved fit relative to single phase (P = .03). Conclusion This deep learning model was able to detect the presence of large vessel occlusion and its diagnostic performance was enhanced by using delayed phases at multiphase CT angiography examinations. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Ospel and Goyal in this issue.