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The increased use of neuroimaging and innovations in ischemic stroke (IS) treatment have improved outcomes, but the impact on median hospital costs is not well understood.A retrospective study was conducted using Medicare 5% claims data for 75,525 consecutive index IS hospitalizations for patients aged ≥65 years from 2012 to 2019 (values in 2019 dollars). IS episode cost was calculated in each year for trend analysis and stratified by cost components, including neuroimaging (CT angiography [CTA], CT perfusion [CTP], MRI, and MR angiography [MRA]), treatment (endovascular thrombectomy [EVT] and/or intravenous thrombolysis), and patient sociodemographic factors. Logistic regression was performed to analyze the drivers of high-cost episodes and median regression to assess drivers of median costs.The median IS episode cost increased by 4.9% from $9,509 in 2012 to $9,973 in 2019 (P = .0021). Treatment with EVT resulted in the greatest odds of having a high-cost ($20,000) hospitalization (odds ratio [OR], 71.86; 95% confidence interval [CI], 54.62-94.55), as did intravenous thrombolysis treatment (OR, 3.19; 95% CI, 2.90-3.52). Controlling for other factors, neuroimaging with CTA (OR, 1.72; 95% CI, 1.58-1.87), CTP (OR, 1.32; 95% CI, 1.14-1.52), and/or MRA (OR, 1.26; 95% CI, 1.15-1.38) had greater odds of having high-cost episodes than those without CTA, CTP, and MRA. Length of stay4 days (OR, 4.34; 95% CI, 3.99-4.72) and in-hospital mortality (OR, 1.85; 95% CI, 1.63-2.10) were also associated with high-cost episodes.From 2012 to 2019, the median IS episode cost increased by 4.9%, with EVT as the main cost driver. However, the increasing treatment cost trends have been partially offset by decreases in median length of stay and in-hospital mortality.

OBJECTIVE Clinical outcomes following endovascular thrombectomy (EVT) for acute ischemic stroke (AIS) treatment are highly time sensitive. Remote robotic (RR)–EVT systems may be capable of mitigating time delays in patient transfer from a primary stroke center (PSC) to a comprehensive/thrombectomy-capable stroke center. However, health economic evidence is needed to assess the costs and benefits of an RR-EVT system. Therefore, the authors of this study aimed to determine whether performing RR-EVT in suspected AIS patients at a PSC as opposed to standard of care might translate to cost-effectiveness over a lifetime. METHODS An economic evaluation study was performed from a US healthcare perspective, combining decision analysis and Markov modeling methods over a lifetime horizon to evaluate the cost-effectiveness of RR-EVT in suspected AIS patients at a PSC compared to the standard-of-care approach. Total expected costs and quality-adjusted life-years (QALYs) were estimated. RESULTS In the cost-effectiveness analysis, RR-EVT yielded greater effectiveness per patient (4.05 vs 3.88 QALYs) and lower costs (US$321,269 vs US$321,397) than the standard-of-care approach. Owing to these lower costs and greater health benefits, RR-EVT was the dominant cost-effective strategy. After initiation of an RR-EVT system, the average costs per year were similar (or slightly reduced), according to this simulation. Sensitivity analyses revealed that RR-EVT remains cost-effective in a wide variety of time delays and cost assumptions. In a one-way sensitivity analysis, RR-EVT remained the most cost-effective strategy when time delays were greater than 2.5 minutes, its complication rate did not exceed 37%, and costs were lower than $54,081. When the cost of the RR-EVT strategy ranged from $19,340 to $54,081 and its complication rate varied from 15% to 37%, the RR-EVT strategy remained the most cost-effective throughout the two ranges. RR-EVT was also the most cost-effective strategy even when its cost doubled (to approximately $40,000) and time delays exceeded 20 minutes. In a probabilistic sensitivity analysis, RR-EVT was the long-term cost-effective strategy in 89.8% of iterations at a willingness-to-pay threshold of $100,000/QALY. CONCLUSIONS This analysis suggests that RR-EVT as an innovative solution to expedite EVT is cost-effective. An RR-EVT system could potentially extend access to care in underserved communities and rural areas, as well as improve care for socioeconomically disadvantaged populations affected by health inequities.

A dose reduction imaging paradigm utilizing chest x-ray (CXR) to triage between computed tomography pulmonary angiography (CTPA) and lung scintigraphy (LS) was introduced in 2001 and adopted in 2012 by the American Thoracic Society/Society of Thoracic Radiology (ATS) guideline for the evaluation of pulmonary embolism in pregnancy. We aimed to assess the utilization of this imaging paradigm preadoption and postadoption by the ATS guideline, and identify factors associated with its utilization.This retrospective cohort study evaluated consecutive pregnant patients who received CTPA or LS for the evaluation of pulmonary embolism in pregnancy at 2 tertiary hospitals between September 2008 and March 2017, excluding 2012 for guideline release washout. Utilization of the imaging paradigm was defined per patient by the use of CXR before advanced imaging, with CTPA performed following positive CXR and LS performed following negative CXR. Multivariate analyses were performed to assess factors associated with utilization of the imaging paradigm. P0.05 is considered significant.Overall, 9.8% (63/643) of studies utilized the dose reduction imaging paradigm, 13.3% (34/256) before the guidelines, and 7.5% (29/387) after. Multivariable analysis showed that the dose reduction imaging paradigm utilization was higher for inpatients (odds ratio [OR]: 4.5) and outpatients (OR: 3.1) relative to the emergency department patients, and lower for second (OR: 0.3) and third (OR: 0.2) trimester patients, without significant differences by study priority, patient age, or patient race.Guideline-recommended dose reduction imaging paradigm utilization was low, and decreased after guideline publication. Utilization varied by patient setting and trimester, which are potential targets for interventions to improve guideline compliance.

The purpose of this study was to update trends, investigate sociodemographic disparities, and evaluate the impact on mortality of stroke neuroimaging across the United States from 2012 to 2019.Retrospective cohort study using CMS Medicare 5% Research Identifiable Files, representing consecutive ischemic stroke emergency department or hospitalized patients aged ≥65 years. A total of 85,547 stroke episodes with demographic and clinical information were analyzed using Cochran-Mantel-Haenszel tests and logistic regression. Outcome measures were neuroimaging (CT angiography [CTA], CT perfusion [CTP], MRI, MR angiography [MRA]) utilization, acute treatment (endovascular thrombectomy [EVT] and intravenous thrombolysis [IVT]), and mortality while in the hospital and at 30 days and 1 year post discharge.Significantly increasing utilization trends for CTA (250%), CTP (428%) and MRI (18%), and a decreasing trend for MRA (-33%) were observed from 2012 to 2019 (P.0001). Controlling for covariates in the logistic regression models, CTA and CTP were significantly associated with higher EVT and IVT utilization. Although CTA, MRI, and MRA were associated with lower mortality, CTP was associated with higher mortality post discharge. Less neuroimaging was performed in rural patients; older patients (≥80 years) had lower utilization of CTA, MRI, and MRA; female patients had lower rates of CTA; and Black patients had lower utilization of CTA and CTP.CTA and CTP utilization increased in the Medicare ischemic stroke population from 2012 to 2019 and both were associated with greater EVT and IVT use. However, disparities exist in neuroimaging utilization across all demographic groups, and further understanding of the root causes of these disparities will be crucial to achieving equity in stroke care.

Prior studies have shown socioeconomic disparities in advanced neuroimaging and acute treatment utilization in patients with ischemic stroke. The authors analyzed whether socioeconomic factors were associated with stroke neuroimaging and acute treatment utilization at a comprehensive stroke center.A retrospective study of consecutive acute ischemic stroke discharges from 2012 to 2020 at a comprehensive stroke center was performed. Differences in neuroimaging (CT angiography [CTA], CT perfusion, MRI, and MR angiography [MRA]) and acute treatment (intravenous thrombolysis [IVT] and endovascular thrombectomy [EVT]) utilization were evaluated on the basis of socioeconomic factors of age, sex, race, insurance type, and neighborhood-level median household income. Chi-square tests were used for bivariate analyses. Multivariable logistic regression analyses were performed to determine associations between socioeconomic factors and neuroimaging or treatment utilization while controlling for stroke-specific factors and comorbidities.Among 6,140 ischemic stroke discharges, race and insurance type were not significantly associated with lower utilization of neuroimaging (CTA, CT perfusion, MRI, and MRA) or acute stroke treatment (IVT and EVT) after controlling for stroke-specific factors and comorbidities. However, median household income$80,000/year was associated with lower IVT use (odds ratio [OR], 0.74; 95% confidence interval [CI], 0.63-0.87). In addition, age ≥ 80 years had lower CTA (OR, 0.62; 95% CI, 0.51-0.75) and EVT (OR, 0.53; 95% CI, 0.39-0.73) utilization, and female sex had lower CTA (OR, 0.78; 95% CI, 0.65-0.93) utilization. Significantly higher utilization was observed for MRI in Asian (OR, 1.33; 95% CI, 1.04-1.69) and uninsured (OR, 1.64; 95% CI, 1.07-2.50) patients and for MRA (OR, 1.24; 95% CI, 1.04-1.49) and EVT (OR, 1.62; 95% CI, 1.20-2.20) in privately insured patients.Once access to a comprehensive stroke center is achieved, socioeconomic disparities in the utilization of health care resources, particularly advanced neuroimaging and acute treatment, may be improved in patients with ischemic stroke.

Purpose To evaluate the diagnostic accuracy of computed tomography angiography (CTA) acquired with shuttle technique (CTAs) and helical CTA (CTAh) for vasospasm, using digital subtraction angiography (DSA) obtained within 24 h as reference standard. Methods Thirty-six patients with suspected vasospasm in the setting of aneurysmal subarachnoid hemorrhage (ASAH, 30/36) or acute inflammatory/infectious conditions (6/36) who underwent CTAs (17/36) or CTAh (19/36) followed by DSA within 24 h were identified retrospectively. Presence of vasospasm in the proximal cerebral arterial segments was assessed qualitatively and semi-quantitatively on CTA and subsequent DSA. Sensitivity, specificity, and receiver operating characteristic (ROC) curves were calculated. Inter-rater variability was assessed using Cohen's kappa. Results On CTAs, 35% of patients had low and 65% had high vasospasm burden. On CTAh, 37% had low and 63% had high vasospasm burden. ROC analysis demonstrated an AUC of 0.87 for CTAs (95%CI 0.67–1.00, p = 0.015) and 0.88 for CTAh (0.72–1.00, p = 0.028). Cohen's kappa was 0.843 (95%CI 0.548–1.000). Thresholding with Youden's J index, CTAs had a sensitivity of 85.71% (95%CI 48.69 to 99.27) and specificity of 66.67% (35.42 to 87.94). CTAh had sensitivity of 100% (56.55 to 100.00) and specificity of 78.57% (52.41 to 92.43). Conclusion CTAs and CTAh yielded similar sensitivity, specificity, and AUC values on ROC analysis for the detection of vasospasm using DSA as reference standard. Our findings suggest that CTAs is a promising alternative to CTAh especially in patients requiring serial imaging, given its potential advantages of decreased radiation exposure, contrast dose, and cost-effectiveness.

BackgroundRapid time to reperfusion is essential to minimize morbidity and mortality in acute ischemic stroke due to large vessel occlusion (LVO). We aimed to evaluate the workflow times when utilizing a direct-to-angiography suite (DTAS) pathway for patients with suspected stroke presenting at a comprehensive stroke center compared with a conventional CT pathway.MethodsWe developed a discrete-event simulation (DES) model to evaluate DTAS workflow timelines compared with a conventional CT pathway, varying the admission NIHSS score treatment eligibility criteria. Model parameters were estimated based on 2 year observational data from our institution. Sensitivity analyses of simulation parameters were performed to assess the impact of patient volume and baseline utilization of angiography suites on workflow times utilizing DTAS.ResultsSimulation modeling of stroke patients (SimStroke) demonstrated door-to-reperfusion time savings of 0.2–3.5 min (p=0.05) for a range of DTAS eligibility criteria (ie, last known well to arrival ConclusionsThe results of the SimStroke model showed comparable time intervals for door-to-reperfusion for DTAS compared with a conventional stroke care pathway. However, the DTAS pathway was very sensitive to baseline angiography suite utilization, with even a 10% increase eliminating the advantages of DTAS compared with the conventional pathway. Given the minimal time savings modeled here, further investigation of implementing the DTAS pathway in clinical care is warranted.

OBJECTIVE The utility of endovascular thrombectomy (EVT) in patients with acute ischemic stroke, large vessel occlusion (LVO), and low Alberta Stroke Program Early CT Scores (ASPECTS) remains uncertain. The objective of this study was to determine the health outcomes and cost-effectiveness of EVT versus medical management in patients with ASPECTS < 6. METHODS A decision-analytical study was performed with Markov modeling to estimate the lifetime quality-adjusted life-years (QALYs) and associated costs of EVT-treated patients compared to medical management. The study was performed over a lifetime horizon with a societal perspective in the US setting. RESULTS The incremental cost-effectiveness ratios were $412,411/QALY and $1,022,985/QALY for 55- and 65-year-old groups in the short-term model. EVT was the long-term cost-effective strategy in 96.16% of the iterations and resulted in differences in health benefit of 2.21 QALYs and 0.79 QALYs in the 55- and 65-year-old age groups, respectively, equivalent to 807 days and 288 days in perfect health. EVT remained the more cost-effective strategy when the probability of good outcome with EVT was above 16.8% or as long as the good outcome associated with the procedure was at least 1.6% higher in absolute value than that of medical management. EVT remained cost-effective even when its cost exceeded $100,000 (threshold was $108,036). Although the cost-effectiveness decreased with age, EVT was cost-effective for 75-year-old patients as well. CONCLUSIONS This study suggests that EVT is the more cost-effective approach compared to medical management in patients with ASPECTS < 6 in the long term (lifetime horizon), considering the poor outcomes and significant disability associated with nonreperfusion.

Objective During the COVID-19 pandemic, Radiology practices experienced marked reductions in outpatient imaging volumes. Our purpose was to evaluate the timing, rate, and degree of recovery of outpatient imaging during the first wave of the pandemic. We also sought to ascertain the relationship of outpatient imaging recovery to the incidence of COVID-19 cases. Methods Retrospective study of outpatient imaging volumes in a large healthcare system was performed from January 1, 2019-August 25, 2020. Dataset was split to compare Pre-COVID (weeks 1–9), Peak-COVID (weeks 10–15) and Recovery-COVID (weeks 16–34) periods. Chi-square and Independent-samples t-tests compared weekly outpatient imaging volumes in 2020 and 2019. Regression analyses assessed the rate of decline and recovery in Peak-COVID and Recovery-COVID periods, respectively. Results Total outpatient imaging volume in 2020 (weeks 1–34) was 327,738 exams, compared to 440,314 in 2019. The 2020 mean weekly imaging volumes were significantly decreased in Peak-COVID (p = 0.0148) and Recovery-COVID (p = 0.0003) periods. Mean weekly decline rate was −2580 exams/week and recovery rate was +617 exams/week. The 2020 Post-COVID (weeks 10–34) period had an average decrease of 36.5% (4813.4/13,178.6) imaging exams/week and total estimated decrease of 120,335 exams. Significant inverse correlation (−0.8338, p

Introduction. The World Health Organization declared COVID-19 a global pandemic last year. While a clear impact of COVID-19 on the declining stroke volume has been reported, its overall impact on stroke presentation and clinical outcomes has not been established. The purpose of this study was to assess the impact of COVID-19 on acute ischemic stroke volume, presentation, treatment, and outcomes at comprehensive stroke centers. Methods. A retrospective review of patients with a discharge diagnosis of acute ischemic stroke from the Get With The Guidelines database was performed from January 1, 2019, to July 1, 2020. The following time periods were defined: Pre-COVID (January/February), Peak-COVID (March/April), and Post-COVID (May/June). Bivariate analyses were performed comparing the 2020 and 2019 time periods to determine differences in stroke volume, presentation, treatment, and outcomes. Results. Stroke volumes were significantly lower during the Peak-COVID period in 2020 compared to that in 2019, with an absolute decline of 49.5% ( P < 0.001 ). Patients were more likely to present after 24 hours from last known well during the 2020 Peak-COVID period ( P = 0.03 ). However, there was not a significant difference in the rate of treatment with either the tissue plasminogen activator (tPA) or mechanical thrombectomy during the Peak-COVID period. Interestingly, relative treatment rates increased during the 2020 Post-COVID period to 11.4% ( P = 0.01 ). Conclusions. The overall ischemic stroke volume decreased during the pandemic, and patients had a tendency to present later, beyond eligible treatment windows. However, rates of treatment, patient demographics, and stroke outcomes did not significantly change when compared to the prior year.

Purpose National guidelines recommend prompt identification of candidates for acute ischemic stroke (AIS) treatment, requiring timely neuroimaging with CT and/or MRI. CT is often preferred because of its widespread availability and rapid acquisition. Despite higher diagnostic accuracy of MRI, it commonly involves complex workflows that could potentially cause treatment time delays. The purpose of this study was to analyze the impact on outcomes of imaging utilization before treatment decisions at comprehensive stroke centers for patients presenting with suspected AIS in the anterior circulation with last-known-well-to-arrival time 0 to 24 hours. Methods A decision simulation model based on the American Heart Association’s recommendations for AIS care pathways was developed from a health care perspective to compare initial imaging strategies: (1) stepwise-CT: noncontrast CT (NCCT) at the time of presentation, with CT angiography (CTA) ± CT perfusion (CTP) only in select patients (initial imaging to exclude hemorrhage and extensive ischemia) for mechanical thrombectomy (MT) evaluation; (2) stepwise-hybrid: NCCT at the time of presentation, with MR angiography (MRA) ± MR perfusion (MRP) only for MT evaluation; (3) stepwise-advanced: NCCT + CTA at presentation, with MR diffusion-weighted imaging (MR DWI) + MRP only for MT evaluation; (4) comprehensive-CT: NCCT + CTA + CTP at the time of presentation; and (5) comprehensive-MR: MR DWI + MRA + MRP at the time of presentation. Model parameters were defined using evidence-based data. Cost-effectiveness and sensitivity analyses were performed. Results The cost-effectiveness analyses revealed that comprehensive-CT and comprehensive-MR yield the highest lifetime quality-adjusted life-years (QALYs) (4.81 and 4.82, respectively). However, the incremental cost-effectiveness ratio of comprehensive-MR is $233,000/QALY compared with comprehensive-CT. Stepwise-CT, stepwise-hybrid, and stepwise-advanced strategies are dominated, yielding lower QALYs and higher costs compared with comprehensive-CT. Conclusions Performing comprehensive-CT at presentation is the most cost-effective initial imaging strategy at comprehensive stroke centers.

BackgroundEvidence has shown that endovascular thrombectomy (EVT) treatment improves clinical outcomes. Yet, its benefit remains uncertain in patients with large established infarcts as defined by ASPECTS (Alberta Stroke Program Early CT Score) MethodsAn economic evaluation study was performed combining a decision tree and Markov model to estimate lifetime costs (2021 US$) and quality-adjusted life years (QALYs) of AIS patients with ASPECTS 3–5. Incremental cost-effectiveness ratios (ICERs), net monetary benefits (NMBs), and deterministic one-way and two-way sensitivity analyses were performed. Probabilistic sensitivity analyses were also performed to evaluate the robustness of our model.ResultsCompared with SC, the cost-effectiveness analyses revealed that EVT yields higher lifetime benefits (2.20 QALYs vs 1.41 QALYs) with higher lifetime healthcare cost per patient ($285 861 vs $272 954). The difference in health benefits between EVT and SC was 0.79 QALYs, equivalent to 288 additional days of healthy life per patient. Even though EVT is more costly than SC alone, it is still cost-effective given better outcomes with ICER of $16 239/QALY. The probabilistic sensitivity analyses indicated that EVT was the most cost-effective strategy in 98.8% (9882 of 10 000) of iterations at the willingness-to-pay threshold of $100 000 per QALY.ConclusionsThe results of this study suggest that EVT is cost-effective in AIS patients with a large ischemic core (ASPECTS 3–5), compared with SC alone over the patient’s lifetime.

Cerebral vasospasm (VS) and delayed cerebral ischemia (DCI) are important complications of aneurysmal subarachnoid hemorrhage (ASAH). Imaging approaches to VS monitoring include noninvasive bedside assessment with transcranial Doppler ultrasonography, angiographic evaluation with digital subtraction angiography, and computed tomography (CT) angiography. DCI is a clinical diagnosis and is not fully explained by the presence of angiographic VS. CT perfusion has shown clinical utility and implications for future research in the evaluation of DCI in patients with ASAH. This review article discusses the common approaches to diagnosis and monitoring of VS and DCI, current treatment strategies, and future research directions.

Objectives To investigate machine learning classifiers and interpretable models using chest CT for detection of COVID-19 and differentiation from other pneumonias, interstitial lung disease (ILD) and normal CTs. Methods Our retrospective multi-institutional study obtained 2446 chest CTs from 16 institutions (including 1161 COVID-19 patients). Training/validation/testing cohorts included 1011/50/100 COVID-19, 388/16/33 ILD, 189/16/33 other pneumonias, and 559/17/34 normal (no pathologies) CTs. A metric-based approach for the classification of COVID-19 used interpretable features, relying on logistic regression and random forests. A deep learning–based classifier differentiated COVID-19 via 3D features extracted directly from CT attenuation and probability distribution of airspace opacities. Results Most discriminative features of COVID-19 are the percentage of airspace opacity and peripheral and basal predominant opacities, concordant with the typical characterization of COVID-19 in the literature. Unsupervised hierarchical clustering compares feature distribution across COVID-19 and control cohorts. The metrics-based classifier achieved AUC = 0.83, sensitivity = 0.74, and specificity = 0.79 versus respectively 0.93, 0.90, and 0.83 for the DL-based classifier. Most of ambiguity comes from non-COVID-19 pneumonia with manifestations that overlap with COVID-19, as well as mild COVID-19 cases. Non-COVID-19 classification performance is 91% for ILD, 64% for other pneumonias, and 94% for no pathologies, which demonstrates the robustness of our method against different compositions of control groups. Conclusions Our new method accurately discriminates COVID-19 from other types of pneumonia, ILD, and CTs with no pathologies, using quantitative imaging features derived from chest CT, while balancing interpretability of results and classification performance and, therefore, may be useful to facilitate diagnosis of COVID-19. Key Points • Unsupervised clustering reveals the key tomographic features including percent airspace opacity and peripheral and basal opacities most typical of COVID-19 relative to control groups. • COVID-19-positive CTs were compared with COVID-19-negative chest CTs (including a balanced distribution of non-COVID-19 pneumonia, ILD, and no pathologies). Classification accuracies for COVID-19, pneumonia, ILD, and CT scans with no pathologies are respectively 90%, 64%, 91%, and 94%. • Our deep learning (DL)–based classification method demonstrates an AUC of 0.93 (sensitivity 90%, specificity 83%). Machine learning methods applied to quantitative chest CT metrics can therefore improve diagnostic accuracy in suspected COVID-19, particularly in resource-constrained environments. Supplementary Information The online version contains supplementary material available at 10.1007/s00330-021-07937-3.

Objective The optimal patient transportation destination of acute ischemic stroke (AIS) patients remains uncertain. The purpose of this study was to evaluate the predictive variables that determine stroke outcomes depending on the patient transportation destination. Methods We performed a retrospective study using an AIS database consisting of patients who underwent thrombectomy admitted to our institution from November 1, 2011, through October 1, 2018. Results A total of 171 patients were included in the statistical analysis; 42.1% (72/171) of patients were in the mothership group (directly admitted) and 57.9% (99/171) in the drip-and-ship group (transferred). Multivariable logistic regression revealed the predictive factors for favorable outcomes were driving distance (expressed in miles) between the patient's home and a comprehensive stroke center (CSC) (odds ratio [OR] = 0.95; 95% confidence interval [CI], 0.90-0.99; P = .035), absence of diabetes mellitus (OR = 3.60; 95% CI, 1.20-10.82; P = .022), lower National Institutes of Health Stroke Scale score at admission (OR = 0.91; 95% CI, 0.85-0.97; P = .003), and shorter symptom onset to CSC arrival time (expressed in hours) (OR = 0.84; 95% CI, 0.72-0.99; P = .038). Conclusions Our study revealed that a shorter driving distance between the patient's home and CSC, absence of diabetes, lower National Institutes of Health Stroke Scale score, and shorter onset to hospital arrival time positively impacted the outcomes of endovascularly treated AIS patients.

lthough intravenous contrast in neuroimaging has become increasingly important in selecting patients for stroke treatment, clinical concerns remain regarding contrast-associated acute kidney injury (CA-AKI). Given the increasing utilization of CT angiography and/or perfusion coupled with cerebral angiography, the purpose of this study was to assess the association of CA-AKI and multi-dose iodinated contrast in acute ischemic stroke (AIS) patients.etrospective review of AIS patients at a comprehensive stroke center was performed from January 2018 to December 2019. Data collection included patient demographics, stroke risk factors, stroke severity, discharge disposition, modified Rankin Scale, contrast type/volume, and creatinine levels (baseline, 48-72 h). CA-AKI was defined as creatinine increase ≥ 25 % from baseline. Bivariate analyses and multivariable logistic regression models were implemented to compare AIS patients with multi-dose and single-dose contrast.Of 440 AIS patients, 215 (48.9 %) were exposed to a single-dose contrast, and 225 (51.1 %) received multi-dose. In single-dose patients, CA-AKI at 48/72 h was 9.7 %/10.2 % compared to 8.0 %/8.9 % in multi-dose patients. Multi-dose patients were significantly more likely to receive a higher volume of contrast (mean 142.1 mL versus 80.8 mL; p lt; 0.001), but there was no significant difference in their creatinine levels or CA-AKI. NIHSS score (OR=1.08, 95 % CI=[1.04,1.13]), and patient transfer from another hospital (OR=3.84, 95 % CI=[1.94,7.62]) were significantly associated with multi-dose contrast.No significant association between multi-dose iodinated contrast and CA-AKI was seen in AIS patients. Concerns of CA-AKI should not deter physicians from pursuing timely and appropriate contrast-enhanced neuroimaging that may optimize treatment outcomes in AIS patients.

PURPOSE: To present a method that automatically detects, subtypes, and locates acute or subacute intracranial hemorrhage (ICH) on noncontrast CT (NCCT) head scans; generates detection confidence scores to identify high-confidence data subsets with higher accuracy; and improves radiology worklist prioritization. Such scores may enable clinicians to better use artificial intelligence (AI) tools. MATERIALS AND METHODS: This retrospective study included 46 057 studies from seven “internal” centers for development (training, architecture selection, hyperparameter tuning, and operating-point calibration; n = 25 946) and evaluation (n = 2947) and three "external" centers for calibration (n = 400) and evaluation (n = 16( )764). Internal centers contributed developmental data, whereas external centers did not. Deep neural networks predicted the presence of ICH and subtypes (intraparenchymal, intraventricular, subarachnoid, subdural, and/or epidural hemorrhage) and segmentations per case. Two ICH confidence scores are discussed: a calibrated classifier entropy score and a Dempster-Shafer score. Evaluation was completed by using receiver operating characteristic curve analysis and report turnaround time (RTAT) modeling on the evaluation set and on confidence score–defined subsets using bootstrapping. RESULTS: The areas under the receiver operating characteristic curve for ICH were 0.97 (0.97, 0.98) and 0.95 (0.94, 0.95) on internal and external center data, respectively. On 80% of the data stratified by calibrated classifier and Dempster-Shafer scores, the system improved the Youden indexes, increasing them from 0.84 to 0.93 (calibrated classifier) and from 0.84 to 0.92 (Dempster-Shafer) for internal centers and increasing them from 0.78 to 0.88 (calibrated classifier) and from 0.78 to 0.89 (Dempster-Shafer) for external centers (P < .001). Models estimated shorter RTAT for AI-prioritized worklists with confidence measures than for AI-prioritized worklists without confidence measures, shortening RTAT by 27% (calibrated classifier) and 27% (Dempster-Shafer) for internal centers and shortening RTAT by 25% (calibrated classifier) and 27% (Dempster-Shafer) for external centers (P < .001). CONCLUSION: AI that provided statistical confidence measures for ICH detection on NCCT scans reliably detected and subtyped hemorrhages, identified high-confidence predictions, and improved worklist prioritization in simulation. Keywords: CT, Head/Neck, Hemorrhage, Convolutional Neural Network (CNN) Supplemental material is available for this article. © RSNA, 2022

Purpose Manifestations of COVID-19 are primarily respiratory based, however, gastrointestinal symptoms are now recognized as an important component of the disease. The purpose of this study is to evaluate differences in abdominal pelvic CT findings in the emergency department by COVID-19 test result. Methods This retrospective study identified patients tested by PCR for COVID-19 infection who underwent abdominal pelvic CT scan in the ED across an academic health system from March 15 to April 15, 2020. Radiology reports were reviewed for the presence of ground glass opacity in the lungs and acute abdominal pathology. A subset of patients with acute abdominal pathology were identified with inflammatory pathology in organs with high ACE2 receptor expression including bowel, pancreas, urinary bladder, and kidney. CT findings for COVID positive versus negative patients were compared with Chi-square test. Results 597 patients tested by PCR for COVID-19 infection underwent abdominal pelvic CT scan, 44% were COVID-19 positive. COVID-19 positive patients demonstrated significantly more ground glass opacity at the lung bases, 65.1%, (222/341) versus 12.4% (33/266), p

Objective The coronavirus disease 2019 (COVID-19) pandemic has had significant economic impact on radiology with markedly decreased imaging case volumes. The purpose of this study was to quantify the imaging volumes during the COVID-19 pandemic across patient service locations and imaging modality types. Methods Imaging case volumes in a large health care system were retrospectively studied, analyzing weekly imaging volumes by patient service locations (emergency department, inpatient, outpatient) and modality types (x-ray, mammography, CT, MRI, ultrasound, interventional radiology, nuclear medicine) in years 2020 and 2019. The data set was split to compare pre-COVID-19 (weeks 1-9) and post-COVID-19 (weeks 10-16) periods. Independent-samples t tests compared the mean weekly volumes in 2020 and 2019. Results Total imaging volume in 2020 (weeks 1-16) declined by 12.29% (from 522,645 to 458,438) compared with 2019. Post-COVID-19 (weeks 10-16) revealed a greater decrease (28.10%) in imaging volumes across all patient service locations (range 13.60%-56.59%) and modality types (range 14.22%-58.42%). Total mean weekly volume in 2020 post-COVID-19 (24,383 [95% confidence interval 19,478-29,288]) was statistically reduced (P = .003) compared with 33,913 [95% confidence interval 33,429-34,396] in 2019 across all patient service locations and modality types. The greatest decline in 2020 was seen at week 16 specifically for outpatient imaging (88%) affecting all modality types: mammography (94%), nuclear medicine (85%), MRI (74%), ultrasound (64%), interventional (56%), CT (46%), and x-ray (22%). Discussion Because the duration of the COVID-19 pandemic remains uncertain, these results may assist in guiding short- and long-term practice decisions based on the magnitude of imaging volume decline across different patient service locations and specific imaging modality types.

Pregnancy-associated pulmonary embolism is one of the leading causes of maternal mortality. Diagnosis of pulmonary embolism in pregnancy is challenging, with symptoms of pulmonary embolism mimicking those of pregnancy. Several key components such as clinical prediction tools, risk stratification, laboratory tests, and imaging widely used for diagnosis of pulmonary embolism in the non-pregnant population show limitations for diagnosis in pregnancy. Further, because of the difficulty of studying pregnant patients, high-quality research evaluating the performance of these diagnostic components in pregnancy is scarce. Seven international medical society guidelines present clinical diagnostic pathways for evaluation of pulmonary embolism in pregnancy that show conflicting recommendations on the use of these diagnostic components. This Review assesses all key components of diagnostic clinical pathways recommended by guidelines for evaluation of pulmonary embolism in pregnancy, reviews current evidence, compares the guideline recommendations with respect to each key component, and provides our preferred diagnostic pathway. It provides the guidelines and available data needed for informed decision making to diagnose pulmonary embolism in pregnancy.

Recurrent stroke patients suffer significant morbidity and mortality, representing almost 30% of the stroke population. Our objective was to determine the clinical outcomes and costs of recurrent ischemic stroke (recurrent-IS).Our study protocol was registered with the International Prospective Register of Systematic Reviews (CRD42020192709). Following PRISMA guidelines, our medical librarian conducted a search in EMBASE, PubMed, Web-of-Science, Scopus, and CINAHL (last performed on August 25, 2020).(1) Studies reporting clinical outcomes and/or costs of recurrent-IS; (2) Original research published in English in year 2010 or later; (3) Study participants aged ≥18 years.(1) Case reports/studies, abstracts/posters, Editorial letters/reviews; (2) Studies analyzing interventions other than intravenous thrombolysis and thrombectomy. Four independent reviewers selected studies with review of titles/abstracts and full-text, and performed data extraction. Discrepancies were resolved by a senior independent arbitrator. Risk-of-bias was assessed using the Mixed Methods Appraisal Tool.Initial search yielded 20,428 studies. Based on inclusion/exclusion criteria, 9 studies were selected, consisting of 24,499 recurrent-IS patients. In 5 studies, recurrent-IS ranged from 4.4-56.8% of the ischemic stroke cohorts at 3 or 12 months, or undefined follow-up. Mean age was 60-80 years and female proportions were 38.5-61.1%. Clinical outcomes included mortality 11.6-25.9% for in-hospital, 30-days, or 4-years (3 studies). In one study from the U.S., mean in-hospital costs were $17,121(SD-$53,693) and 1-year disability costs were $34,639(SD-$76,586) per patient.Our study highlights the paucity of data on clinical outcomes and costs of recurrent-IS and identifies gaps in existing literature to direct future research.

The purpose of this study is to determine the rates of CT pulmonary angiography (CTPA) interpreted as limited and severely limited in pregnant patients suspected for pulmonary embolism (PE), and to evaluate factors that influence these rates. This is a retrospective study with CTPA for evaluation of PE in pregnancy across a large health system from 2006 to 2017. CTPA was classified as limited from the radiology report with a subset of those studies classified as severely limited. Bivariate and multivariate analysis was performed for limited and severely limited rates with maternal age and patient size as a continuous variable and race, trimester, patient location study priority status, and result of chest radiograph before CTPA as categorical variables. 874 patients with 33% of studies limited and 4% of studies severely limited. Multivariate logistic regression of CTPA studies revealed decreasing patient age (OR 0.967, p = 0.0129) and increasing patient size (OR 1.013, p

Background Effective dose (ED) is used to understand radiation-related cancer risk of CT scans. Currently, ED for low-dose CT (LDCT) lung cancer screening (LCS) is estimated by multiplying the CT scan-reported dose-length product (DLP) by a DLP-to-ED conversion factor (k-factor) for general chest CT imaging, which does not account for sex. The purpose of this study was to calculate sex-specific k-factors for LDCT LCS. Methods This retrospective study evaluated consecutive LCS patients across a large health system from 2016 to 2017. Patient and CT scan-related data were obtained from the radiology information system, the picture archiving and communication system, and a radiation dose index-monitoring system. Each patient’s ED was determined by patient-specific Monte-Carlo simulation using Cristy phantoms and divided by study DLP to determine the k-factor. The k-factors were compared vs the standard of 0.014 mSv·mGy⁻1·cm⁻1 for a chest CT scan by using a one-sample Student t test. Bivariate and multivariable analyses were performed for k-factors based on patient and CT scan factors. Results A total of 1,890 patients were included in the study. The mean k-factor for all patients was 0.0179 mSv·mGy⁻1·cm⁻1, which was 22% greater than the standard value of 0.014 mSv·mGy⁻1·cm⁻1 for a chest CT scan previously applied to LDCT imaging (P Conclusions The overall k-factor for LCS is higher than the previously used value for chest CT imaging; when stratified according to sex, it was 43% greater in women than in men. Sex- and LCS-specific k-factors should be used to estimate effective radiation dose in LCS programs.

As "time is brain" in acute stroke triage, the need for automated prognostication tools continues to increase, particularly in rapidly expanding tele-stroke settings. We aimed to create an automated prognostication tool for anterior circulation large vessel occlusion (LVO) stroke based on admission CTA radiomics.We automatically extracted 1116 radiomics features from the anterior circulation territory on admission CTAs of 829 acute LVO stroke patients who underwent mechanical thrombectomy in two academic centers. We trained, optimized, validated, and compared different machine-learning models to predict favorable outcome (modified Rankin Scale ≤ 2) at discharge and 3-month follow-up using four different input sets: "Radiomics", "Radiomics + Treatment" (radiomics, post-thrombectomy reperfusion grade, and intravenous thrombolysis), "Clinical + Treatment" (baseline clinical variables and treatment), and "Combined" (radiomics, treatment, and baseline clinical variables).For discharge outcome prediction, models were optimized/trained on n = 494 and tested on an independent cohort of n = 100 patients from Yale. Receiver operating characteristic analysis of the independent cohort showed no significant difference between best-performing Combined input models (area under the curve, AUC = 0.77) versus Radiomics + Treatment (AUC = 0.78, p = 0.78), Radiomics (AUC = 0.78, p = 0.55), or Clinical + Treatment (AUC = 0.77, p = 0.87) models. For 3-month outcome prediction, models were optimized/trained on n = 373 and tested on an independent cohort from Yale (n = 72), and an external cohort from Geisinger Medical Center (n = 232). In the independent cohort, there was no significant difference between Combined input models (AUC = 0.76) versus Radiomics + Treatment (AUC = 0.72, p = 0.39), Radiomics (AUC = 0.72, p = 0.39), or Clinical + Treatment (AUC = 76, p = 0.90) models; however, in the external cohort, the Combined model (AUC = 0.74) outperformed Radiomics + Treatment (AUC = 0.66, p 0.001) and Radiomics (AUC = 0.68, p = 0.005) models for 3-month prediction.Machine-learning signatures of admission CTA radiomics can provide prognostic information in acute LVO stroke candidates for mechanical thrombectomy. Such objective and time-sensitive risk stratification can guide treatment decisions and facilitate tele-stroke assessment of patients. Particularly in the absence of reliable clinical information at the time of admission, models solely using radiomics features can provide a useful prognostication tool.

BackgroundTo evaluate the cost-effectiveness of endovascular thrombectomy (EVT) to treat large vessel occlusion (LVO) in patients with acute, minor stroke (National Institute of Health Stroke Scale (NIHSS) MethodsA Markov decision-analytic model was constructed accounting for both costs and outcomes from a societal perspective. Two different management strategies were evaluated: EVT and medical management. Base case analysis was done for three different sites of occlusion: proximal M1, distal M1 and M2 occlusions. One-way, two-way and probabilistic sensitivity analyses were performed.ResultsBase-case calculation showed EVT to be the dominant strategy in 65-year-old patients with proximal M1 occlusion and NIHSS ConclusionsEVT is cost-effective in patients with minor stroke and LVO in the long term (lifetime horizon), considering the poor outcomes and significant disability associated with non-reperfusion. Our study emphasizes the need for caution in interpreting previous observational studies which concluded similar results in EVT versus medical management in patients with minor stroke due to a high proportion of patients with M2 occlusions in the two strategies.

Pulmonary embolism (PE) remains a leading cause of maternal mortality, yet diagnosis remains challenging. International diagnostic guidelines vary significantly in their recommendations, making it difficult to determine an optimal policy for evaluation.Which societal-level diagnostic guidelines for evaluation of suspected PE in pregnancy are an optimal policy in terms of its cost-effectiveness?We constructed a complex Markov decision model to evaluate the cost-effectiveness of each identified societal guidelines for diagnosis of PE in pregnancy. Our model accounted for risk stratification, empiric treatment, diagnostic testing strategies, as well as short- and long-term effects from PE, treatment with low-molecular-weight heparin, and radiation exposure from advanced imaging. We considered clinical and cost outcomes of each guideline from a US health care system perspective with a lifetime horizon. Clinical effectiveness and costs were measured in time-discounted quality-adjusted life years (QALYs) and US dollars, respectively. Strategies were compared using the incremental cost-effectiveness ratio (ICER) with a willingness-to-pay threshold of $100,000/QALY. One-way, multiway, and probabilistic sensitivity analyses were performed.We identified six international societal-level guidelines. Base-case analysis showed the guideline proposed by the American Thoracic Society and Society of Thoracic Radiology (ATS-STR) yielded the highest health benefits (22.90 QALYs) and was cost-effective, with an ICER of $7,808 over the guidelines proposed by the Australian Society of Thrombosis and Haemostasis and the Society of Obstetric Medicine of Australia and New Zealand (ASTH-SOMANZ). All remaining guidelines were dominated. The ATS-STR guideline-recommended strategy yielded an expected additional 2.7 QALYs/100 patients evaluated over the ASTH-SOMANZ. Conclusions were robust to sensitivity analyses, with the ATS-STR guidelines optimal in 86% of probabilistic sensitivity analysis scenarios.The ATS-STR guidelines for diagnosis of suspected PE in pregnancy are cost-effective and generate better expected health outcomes than guidelines proposed by other medical societies.

BACKGROUND AND PURPOSE: Indirect consequences of the Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) pandemic include those related to failure of patients to seek or receive timely medical attention for seemingly unrelated disease. We report our experience with stroke code imaging during the early pandemic months of 2020. MATERIALS AND METHODS: Retrospective review of stroke codes during the 2020 pandemic and both 2020 and matched 2019 prepandemic months was performed. Patient variables were age, sex, hospital location, and severity of symptoms based on the NIHSS. We reviewed the results of CT of the head, CTA, CTP, and MR imaging examinations and classified a case as imaging-positive if any of the imaging studies yielded a result that related to the clinical indication for the study. Both year-to-year and sequential comparisons were performed between pandemic and prepandemic months. RESULTS: A statistically significant decrease was observed in monthly stroke code volumes accompanied by a statistically significant increased proportion of positive imaging findings during the pandemic compared with the same months in the prior year (P < .001) and prepandemic months in the same year (P < .001). We also observed statistically significant increases in average NIHSS scores (P = .045 and P = .03) and the proportion of inpatient stroke codes (P = .003 and P = .03). CONCLUSIONS: During our pandemic period, there was a significantly decreased number of stroke codes but simultaneous increases in positivity rates, symptom severity, and inpatient codes. We postulate that this finding reflects the documented reluctance of patients to seek medical care during the pandemic, with the shift toward a greater proportion of inpatient stroke codes potentially reflecting the neurologic complications of the virus itself.

Background and Purpose— Our study aims to evaluate the cost-effectiveness of computed tomography angiography (CTA) for surveillance of tiny unruptured intracranial aneurysms and the impact of CTA radiation-induced brain tumor on the overall effectiveness of CTA. Methods— A Markov decision model was constructed from a societal perspective starting with patients 30-, 40-, or 50-year-old, with incidental detection of unruptured intracranial aneurysm ≤3 mm and no prior history of subarachnoid hemorrhage. Five different management strategies were assessed (1) annual CTA surveillance, (2) biennial CTA, (3) CTA follow-up every 5 years, (4) coiling and subsequent magnetic resonance imaging follow-up, and (5) annual CTA surveillance for the first 2 years, followed by every 5-year CTA follow-up. Probabilistic, 1-way, and 2-way sensitivity analyses were performed. Results— The base case calculation shows every 5-year CTA follow-up to be the most cost-effective strategy, and the conclusion remains robust in probabilistic sensitivity analysis. It remains the dominant strategy when the annual rupture risk of nongrowing unruptured intracranial aneurysms is smaller than 2.66% or the rupture risk in growing aneurysms is Conclusions— Given the current literature, every 5-year CTA imaging follow-up is the cost-effective strategy in patients with aneurysms ≤3 mm, resulting in better health outcomes and lower healthcare spending. Patients with aneurysms at high risk of rupture might need more aggressive management.