Quantitative Evaluation of Large Language Models to Streamline Radiology Report Impressions: A Multimodal Retrospective Analysis.

Background The complex medical terminology of radiology reports may cause confusion or anxiety for patients, especially given increased access to electronic health records. Large language models (LLMs) can potentially simplify radiology report readability. Purpose To compare the performance of four publicly available LLMs (ChatGPT-3.5 and ChatGPT-4, Bard [now known as Gemini], and Bing) in producing simplified radiology report impressions. Materials and Methods In this retrospective comparative analysis of the four LLMs (accessed July 23 to July 26, 2023), the Medical Information Mart for Intensive Care (MIMIC)-IV database was used to gather 750 anonymized radiology report impressions covering a range of imaging modalities (MRI, CT, US, radiography, mammography) and anatomic regions. Three distinct prompts were employed to assess the LLMs' ability to simplify report impressions. The first prompt (prompt 1) was "Simplify this radiology report." The second prompt (prompt 2) was "I am a patient. Simplify this radiology report." The last prompt (prompt 3) was "Simplify this radiology report at the 7th grade level." Each prompt was followed by the radiology report impression and was queried once. The primary outcome was simplification as assessed by readability score. Readability was assessed using the average of four established readability indexes. The nonparametric Wilcoxon signed-rank test was applied to compare reading grade levels across LLM output. Results All four LLMs simplified radiology report impressions across all prompts tested (P < .001). Within prompts, differences were found between LLMs. Providing the context of being a patient or requesting simplification at the seventh-grade level reduced the reading grade level of output for all models and prompts (except prompt 1 to prompt 2 for ChatGPT-4) (P < .001). Conclusion Although the success of each LLM varied depending on the specific prompt wording, all four models simplified radiology report impressions across all modalities and prompts tested. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Rahsepar in this issue.

Cost-Effectiveness of CT, CTA, MRI, and Specialized MRI for Evaluation of Patients Presenting to the Emergency Department With Dizziness.

BACKGROUND. Underlying stroke is often misdiagnosed in patients presenting with dizziness. Although such patients are usually ineligible for acute stroke treatment, accurate diagnosis may still improve outcomes through selection of patients for secondary prevention measures. OBJECTIVE. The purpose of our study was to investigate the cost-effectiveness of differing neuroimaging approaches in the evaluation of patients presenting to the emergency department (ED) with dizziness who are not candidates for acute intervention. METHODS. A Markov decision-analytic model was constructed from a health care system perspective for the evaluation of a patient presenting to the ED with dizziness. Four diagnostic strategies were compared: noncontrast head CT, head and neck CTA, conventional brain MRI, and specialized brain MRI (including multiplanar high-resolution DWI). Differing long-term costs and outcomes related to stroke detection and secondary prevention measures were compared. Cost-effectiveness was calculated in terms of lifetime expenditures in 2022 U.S. dollars for each quality-adjusted life year (QALY); deterministic and probabilistic sensitivity analyses were performed. RESULTS. Specialized MRI resulted in the highest QALYs and was the most cost-effective strategy with US$13,477 greater cost and 0.48 greater QALYs compared with noncontrast head CT. Conventional MRI had the next-highest health benefit, although was dominated by extension with incremental cost of US$6757 and 0.25 QALY; CTA was also dominated by extension, with incremental cost of US$3952 for 0.13 QALY. Non-contrast CT alone had the lowest utility among the four imaging choices. In the deterministic sensitivity analyses, specialized MRI remained the most cost-effective strategy. Conventional MRI was more cost-effective than CTA across a wide range of model parameters, with incremental cost-effectiveness remaining less than US$30,000/QALY. Probabilistic sensitivity analysis yielded similar results as found in the base-case analysis, with specialized MRI being more cost-effective than conventional MRI, which in turn was more cost-effective than CTA. CONCLUSION. The use of MRI in patients presenting to the ED with dizziness improves stroke detection and selection for subsequent preventive measures. MRI-based evaluation leads to lower long-term costs and higher cumulative QALYs. CLINICAL IMPACT. MRI, incorporating specialized protocols when available, is the preferred approach for evaluation of patients presenting to the ED with dizziness, to establish a stroke diagnosis and to select patients for secondary prevention measures.

CT With CTA Versus MRI in Patients Presenting to the Emergency Department With Dizziness: Analysis Using Propensity Score Matching.

BACKGROUND. CT with CTA is widely used to exclude stroke in patients with dizziness, although MRI has higher sensitivity. OBJECTIVE. The purpose of this article was to compare patients presenting to the emergency department (ED) with dizziness who undergo CT with CTA alone versus those who undergo MRI in terms of stroke-related management and outcomes. METHODS. This retrospective study included 1917 patients (mean age, 59.5 years; 776 men, 1141 women) presenting to the ED with dizziness from January 1, 2018, to December 31, 2021. A first propensity score matching analysis incorporated demographic characteristics, medical history, findings from the review of systems, physical examination findings, and symptoms to construct matched groups of patients discharged from the ED after undergoing head CT with head and neck CTA alone and patients who underwent brain MRI (with or without CT and CTA). Outcomes were compared. A second analysis compared matched patients discharged after CT with CTA alone and patients who underwent specialized abbreviated MRI using multiplanar high-resolution DWI for increased sensitivity for posterior circulation stroke. Sensitivity analyses were performed involving MRI examinations performed as the first or only neuroimaging examination and involving alternative matching and imputation techniques. RESULTS. In the first analysis (406 patients per group), patients who underwent MRI, compared with patients who underwent CT with CTA alone, showed greater frequency of critical neuroimaging results (10.1% vs 4.7%, p = .005), change in secondary stroke prevention medication (9.6% vs 3.2%, p = .001), and subsequent echocardiography evaluation (6.4% vs 1.0%, p < .001). In the second analysis (100 patients per group), patients who underwent specialized abbreviated MRI, compared with patients who underwent CT with CTA alone, showed greater frequency of critical neuroimaging results (10.0% vs 2.0%, p = .04), change in secondary stroke prevention medication (14.0% vs 1.0%, p = .001), and subsequent echocardiography evaluation (12.0% vs 2.0%, p = .01) and lower frequency of 90-day ED readmissions (12.0% vs 28.0%, p = .008). Sensitivity analyses showed qualitatively similar findings. CONCLUSION. A proportion of patients discharged after CT with CTA alone may have benefitted from alternative or additional evaluation by MRI (including MRI using a specialized abbreviated protocol). CLINICAL IMPACT. Use of MRI may motivate clinically impactful management changes in patients presenting with dizziness.

Artificial Intelligence to Improve Patient Understanding of Radiology Reports.

Diagnostic imaging reports are generally written with a target audience of other providers. As a result, the reports are written with medical jargon and technical detail to ensure accurate communication. With implementation of the 21st Century Cures Act, patients have greater and quicker access to their imaging reports, but these reports are still written above the comprehension level of the average patient. Consequently, many patients have requested reports to be conveyed in language accessible to them. Numerous studies have shown that improving patient understanding of their condition results in better outcomes, so driving comprehension of imaging reports is essential. Summary statements, second reports, and the inclusion of the radiologist's phone number have been proposed, but these solutions have implications for radiologist workflow. Artificial intelligence (AI) has the potential to simplify imaging reports without significant disruptions. Many AI technologies have been applied to radiology reports in the past for various clinical and research purposes, but patient focused solutions have largely been ignored. New natural language processing technologies and large language models (LLMs) have the potential to improve patient understanding of their imaging reports. However, LLMs are a nascent technology and significant research is required before LLM-driven report simplification is used in patient care.

A systematic review of cost-effectiveness analyses on endovascular thrombectomy in ischemic stroke patients.

OBJECTIVE: The objective of this study was to examine the published cost-effectiveness analyses (CEAs) on endovascular thrombectomy (EVT) in acute stroke patients, with a particular focus on the practice of accounting for costs and utilities. METHODS: We conducted a systematic review of published CEAs on EVT in acute stroke patients from 1/1/2009 to 10/1/2019. Published CEAs were searched in Ovid Embase, Ovid MEDLINE, and Web of Science. Cost or comparative effectiveness analyses were excluded. Risk of bias and quality assessment was based on the Consolidated Health Economic Evaluation Reporting Standard checklist. RESULTS: Twenty-one studies were included in the final analysis, from the USA, Canada, Europe, Asia, and Australia. They all concluded EVT to be cost-effective, but with significant variations in methodology. Fifteen studies employed a long-term horizon (> 20 years), while only 11 incorporated risk of recurrent strokes. The willingness-to-pay (WTP) threshold varied from $10,000/quality-adjusted life year (QALY) to $120,000/QALY, with $50,000/QALY and $100,000/QALY being the most commonly used. Five studies undertook a societal perspective, but only one accounted for indirect costs. Seventeen studies based outcomes on 90-day modified Rankin Scale (mRS) scores, and 9 of these 17 studies grouped outcomes by mRS 0-2 and 3-5. Among these 9 studies, the range of QALY score reported for mRS 0-2 was 0.71-0.85 QALY, and that of mRS 3-5 was 0.21-0.40. CONCLUSIONS: Our study reveals significant heterogeneity in previously published thrombectomy CEAs, highlighting need for better standardization in future CEAs. KEY POINTS: • All included studies concluded thrombectomy to be cost-effective, from both long- and short-term perspectives. • Only 5 out of 22 studies undertook a societal perspective, and only 1 accounted for indirect costs. • The range of value for mRS 0-2 was 0.71-0.85 quality-adjusted life year (QALY) and 0.21-0.40 QALY for mRS 3-5.

Head and Neck CTA Utilization: Analysis of Ordering Frequency and Nonroutine Results Communication, With Focus on the 50 Most Common Emergency Department Clinical Presentations.

BACKGROUND. Utilization of head and neck CTA in the emergency department (ED) has grown disproportionately to other neuroimaging examinations. OBJECTIVE. The purpose of this article was to characterize utilization of head and neck CTA in the ED, comparing utilization and frequency of nonroutine results communication among patients' chief concerns. METHODS. All adult ED visits for a single health care system from January 2014 to December 2017 were retrospectively reviewed. Variables recorded included chief concerns, whether head and neck CTA was performed, and, if so, whether the report documented nonroutine results communication. The 50 chief concerns resulting in the highest number of head and neck CTA examinations were identified. Frequencies of head and neck CTA ordering and of nonroutine results communication were calculated. A subset of reports documenting nonroutine communication were manually reviewed. RESULTS. Head and neck CTA was ordered in 2.5% (17,903) of 708,145 ED visits in 236,476 patients (mean age, 49.8 ± 20.5 [SD] years; 110,952 men, 125,521 women, 3 unknown sex). Head and neck CTA was ordered for 833 distinct chief concerns. Nonroutine results communication was documented for 17.6% (3155/17,903) of examinations. Among the 50 chief concerns associated with the highest number of examinations, frequency of ordering head and neck CTA ranged from less than 0.5% (five concerns) to 55.2% (stroke code), and frequency of nonroutine communication ranged from 5.6% (transient ischemic attack) to 67.5% (unresponsive). Chief concerns not among the 50 most common accounted for 50.0% (8956/17,903) of examinations; these exhibited a collective frequency of nonroutine communication of 4.8% (429/8956). Manual review of 11.1% (350/3155) of reports with a nonroutine communication indicated an acute finding related to the indication in 51.1%, nonemergent but potentially explanatory finding in 14.0%, incidental finding in 28.0%, and communication of negative results in 6.9%. CONCLUSION. Head and neck CTA is ordered in 2.5% of ED visits for a wide range of chief concerns. Frequencies of ordering and of nonroutine results communication are highly variable among chief concerns. Acute indication-related findings account for half of nonroutine radiologist communications. CLINICAL IMPACT. Insight into patterns regarding head and neck CTA ordering and nonroutine results may help optimize patient selection and radiologist communications in the ED setting.

Scenarios to improve CT head utilization in the emergency department delineated by critical results reporting.

PURPOSE: Increasing use of advanced imaging in the emergency department (ED) has resulted in higher cost without better outcomes. Our goal was to evaluate the yield of CT head exams by scenario to guide efforts at improving patient selection. METHODS: We performed a retrospective study at an academic medical center over 4 years (1/1/2014-12/31/2017). The chief complaint, imaging order, and exam result text were obtained for all adult ED encounters. For the 50 most common chief complaints leading to CT head exams, the ratio of exams to total encounters and ratio of critical results to imaging studies were calculated. Significant difference in "yield" was assessed via binomial test. RESULTS: Over 708,145 adult ED encounters, 58,783 CT head exams were ordered, with an overall critical result yield of 8.0%. The three most common chief complaints had higher yield (p < 0.05): altered mental status (9.8%), fall (9.7%), and new headache (10.1%). Lower yield (p < 0.05) was found for 19 chief complaints: dizziness (6.2%), falls in patients > 65 years old (7.1%), syncope (5.3%), seizure with known epilepsy (4.8%), chest pain (3.7%), head injury (4.9%), headache re-evaluation (7.0%), alcohol intoxication (2.5%), fatigue (6.5%), headache-recurrent or in the setting of known migraines (5.2%), hypertension (4.4%), lethargy (5.8%), loss of consciousness (5.3%), migraine (3.2%), psychiatric evaluation (2.9%), near syncope (4.6%), drug problem (3.1%), symptomatically decreased blood sugar (3.2%), and suicidal (1.7%). CONCLUSION: Our study provides a priority list of low yield scenarios of CT head use for improvement of patient selection.

Patient Electronic Access to Final Radiology Reports: What Is the Current Standard of Practice, and Is an Embargo Period Appropriate?

Patients have a right to their medical records, and it has become commonplace for institutions to set up online portals through which patients can access their electronic health information, including radiology reports. However, institutional approaches vary on how and when such access is provided. Many institutions have advocated built-in "embargo" periods, during which radiology reports are not immediately released to patients, to give ordering clinicians the opportunity to first receive, review, and discuss the radiology report with their patients. To understand current practices, a telephone survey was conducted of 83 hospitals identified in the 2019-2020 U.S. News & World Report Best Hospitals Rankings. Of 70 respondents, 91% (64 of 70) offered online portal access. Forty-two percent of those with online access (27 of 64 respondents) reported a delay of 4 days or longer, and 52% (33 of 64 respondents) indicated that they first send reports for review by the referring clinician before releasing to the patient. This demonstrates a lack of standardized practice in prompt patient access to health records, which may soon be mandated under the final rule of the 21st Century Cures Act. This article discusses considerations and potential benefits of early access for patients, radiologists, and primary care physicians in communicating health information and providing patient-centered care. © RSNA, 2021.

Trends in Differences in Health Status and Health Care Access and Affordability by Race and Ethnicity in the United States, 1999-2018.

IMPORTANCE: The elimination of racial and ethnic differences in health status and health care access is a US goal, but it is unclear whether the country has made progress over the last 2 decades. OBJECTIVE: To determine 20-year trends in the racial and ethnic differences in self-reported measures of health status and health care access and affordability among adults in the US. DESIGN, SETTING, AND PARTICIPANTS: Serial cross-sectional study of National Health Interview Survey data, 1999-2018, that included 596 355 adults. EXPOSURES: Self-reported race, ethnicity, and income level. MAIN OUTCOMES AND MEASURES: Rates and racial and ethnic differences in self-reported health status and health care access and affordability. RESULTS: The study included 596 355 adults (mean [SE] age, 46.2 [0.07] years, 51.8% [SE, 0.10] women), of whom 4.7% were Asian, 11.8% were Black, 13.8% were Latino/Hispanic, and 69.7% were White. The estimated percentages of people with low income were 28.2%, 46.1%, 51.5%, and 23.9% among Asian, Black, Latino/Hispanic, and White individuals, respectively. Black individuals with low income had the highest estimated prevalence of poor or fair health status (29.1% [95% CI, 26.5%-31.7%] in 1999 and 24.9% [95% CI, 21.8%-28.3%] in 2018), while White individuals with middle and high income had the lowest (6.4% [95% CI, 5.9%-6.8%] in 1999 and 6.3% [95% CI, 5.8%-6.7%] in 2018). Black individuals had a significantly higher estimated prevalence of poor or fair health status than White individuals in 1999, regardless of income strata (P < .001 for the overall and low-income groups; P = .03 for middle and high-income group). From 1999 to 2018, racial and ethnic gaps in poor or fair health status did not change significantly, with or without income stratification, except for a significant decrease in the difference between White and Black individuals with low income (-6.7 percentage points [95% CI, -11.3 to -2.0]; P = .005); the difference in 2018 was no longer statistically significant (P = .13). Black and White individuals had the highest levels of self-reported functional limitations, which increased significantly among all groups over time. There were significant reductions in the racial and ethnic differences in some self-reported measures of health care access, but not affordability, with and without income stratification. CONCLUSIONS AND RELEVANCE: In a serial cross-sectional survey study of US adults from 1999 to 2018, racial and ethnic differences in self-reported health status, access, and affordability improved in some subgroups, but largely persisted.

Urgent Care Centers Delay Emergent Surgical Care Based on Patient Insurance Status in The United States.

OBJECTIVE: Patients may call urgent care centers (UCCs) with urgent surgical conditions but may not be properly referred to a higher level of care. This study aims to characterize how UCCs manage Medicaid and privately insured patients who present with an emergent condition. METHODS: Using a standardized script, we called 1245 randomly selected UCCs in 50 states on 2 occasions. Investigators posed as either a Medicaid or a privately-insured patient with symptoms of an incarcerated inguinal hernia. Rates of direct emergency department (ED) referral were compared between insurance types. RESULTS: A total of 1223 (98.2%) UCCs accepted private insurance and 981 (78.8%) accepted Medicaid. At the 971 (78.0%) UCCs that accepted both insurance types, direct-to-ED referral rates for private and Medicaid patients were 27.9% and 33.8%, respectively. Medicaid patients were significantly more likely than private patients to be referred to the ED [odds ratio (OR) 1.32, 95% confidence interval (CI) 1.09-1.60]. Private patients who were triaged by a clinician compared to nonclinician staff were over 6 times more likely to be referred to the ED (OR 6.46, 95% CI 4.63-9.01). Medicaid patients were nearly 9 times more likely to have an ED referral when triaged by a clinician (OR 8.72, 95% CI 6.19-12.29). CONCLUSIONS: Only one-third of UCCs across the United States referred an apparent emergent surgical case to the ED, potentially delaying care. Medicaid patients were more likely to be referred directly to the ED versus privately insured patients. All patients triaged by clinicians were significantly more likely to be referred to the ED; however, the disparity between private and Medicaid patients remained.

The Economic Impact of the COVID-19 Pandemic on Radiology Practices.

The coronavirus 2019 (COVID-19) pandemic will have a profound impact on radiology practices across the country. Policy measures adopted to slow the transmission of disease are decreasing the demand for imaging independent of COVID-19. Hospital preparations to expand crisis capacity are further diminishing the amount of appropriate medical imaging that can be safely performed. Although economic recessions generally tend to result in decreased health care expenditures, radiology groups have never experienced an economic shock that is simultaneously exacerbated by the need to restrict the availability of imaging. Outpatient-heavy practices will feel the biggest impact of these changes, but all imaging volumes will decrease. Anecdotal experience suggests that radiology practices should anticipate 50%-70% decreases in imaging volume that will last a minimum of 3-4 months, depending on the location of practice and the severity of the COVID-19 pandemic in each region. The Coronavirus Aid, Relief, and Economic Security, or CARES, Act provides multiple means of direct and indirect aid to health care providers and small businesses. The final allocation of this funding is not yet clear, and it is likely that additional congressional action will be necessary to stabilize health care markets. Administrators and practice leaders must be proactive with practice modifications and financial maneuvers that can position them to emerge from this pandemic in the most viable economic position. It is possible that this crisis will have lasting effects on the structure of the radiology field.

Gender Disparity in Industry Relationships With Academic Interventional Radiology Physicians.

OBJECTIVE. Industry relationships drive technologic innovation in interventional radiology and offer opportunities for professional growth. Women are underrepresented in interventional radiology despite the growing recognition of the importance of diversity. This study characterized gender disparities in financial relationships between industry and academic interventional radiologists. MATERIALS AND METHODS. In this retrospective cross-sectional study, U.S. academic interventional radiology physicians and their academic ranks were identified by searching websites of practices with accredited interventional radiology fellowship programs. Publicly available databases were queried to collect each physician's gender, years since medical school graduation, h-index, academic rank, and industry payments in 2018. Wilcoxon and chi-square tests compared payments between genders. A general linear model assessed the impact of academic rank, years since graduation, gender, and h-index on payments. RESULTS. Of 842 academic interventional radiology physicians, 108 (13%) were women. A total $14,206,599.41 was received by 686 doctors (81%); only $147,975.28 (1%) was received by women. A lower percentage of women (74%) than men (83%) received payments (p = 0.04); median total payments were lower for women ($535) than men ($792) (p = 0.01). Academic rank, h-index, years since graduation, and male gender were independent predictors of higher payments. Industry payments supporting technologic advancement were made exclusively to men. CONCLUSION. Female interventional radiology physicians received fewer and lower industry payments, earning 1% of total payments despite constituting 13% of physicians. Gender independently predicted industry payments, regardless of h-index, academic rank, or years since graduation. Gender disparity in interventional radiology physician-industry relationships warrants further investigation and correction.

Clinical effectiveness and cost-effectiveness of teledermatology: Where are we now, and what are the barriers to adoption?

There has been rapid growth in teledermatology over the past decade, and teledermatology services are increasingly being used to support patient care across a variety of care settings. Teledermatology has the potential to increase access to high-quality dermatologic care while maintaining clinical efficacy and cost-effectiveness. Recent expansions in telemedicine reimbursement from the Centers for Medicare & Medicaid Services (CMS) ensure that teledermatology will play an increasingly prominent role in patient care. Therefore, it is important that dermatologists be well informed of both the promises of teledermatology and the potential practice challenges a continuously evolving mode of care delivery brings. In this article, we will review the evidence on the clinical and cost-effectiveness of teledermatology and we will discuss system-level and practice-level barriers to successful teledermatology implementation as well as potential implications for dermatologists.

Cost-Effectiveness of Computed Tomography Angiography in Management of Tiny Unruptured Intracranial Aneurysms in the United States.

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 <57.4%. The radiation-induced brain cancer risk is relatively low, and sensitivity analysis shows that the radiation-induced cancer risk does not influence the conclusions unless the risk exceeds 663-fold of the base case values. 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.

Comparative Effectiveness of Endovascular Thrombectomy in Elderly Stroke Patients.

Background and Purpose- Strokes in patients aged ≥80 years are common, and advanced age is associated with relatively poor poststroke functional outcome. The current guidelines do not recommend an upper age limit for endovascular thrombectomy (EVT). The purpose of this study is to evaluate the effectiveness of EVT in acute stroke because of large vessel occlusion for elderly patients >age 80 years. Methods- A Markov decision analytic model was constructed from a societal perspective to evaluate health outcomes in terms of quality-adjusted life years (QALYs) after EVT for acute ischemic stroke because of large vessel occlusion in patients above age 80 years. Age-specific input parameters were obtained from the most recent/comprehensive literature. Good outcome was defined as a modified Rankin Scale score ≤2. Probabilistic, 1-way, and 2-way sensitivity analyses were performed for both healthy patients and patients with disability at baseline. Results- Base case calculation showed in functionally independent patients at baseline, intravenous thrombolysis (IVT) with tPA (tissue-type plasminogen activator) only to be the better strategy with 3.76 QALYs compared to 2.93 QALYs for patients undergoing EVT. The difference in outcome is 0.83 QALY (equivalent to 303 days of life in perfect health). For patients with baseline disability, IVT only yields a utility of 1.92 QALYs and EVT yields a utility of 1.65 QALYs. The difference is 0.27 QALYs (equivalent to 99 days of life in perfect health). Multiple sensitivity analyses showed that the effectiveness of EVT is significantly determined by the morbidity and mortality after both IVT and EVT strategies, respectively. Conclusions- Our study demonstrates the impact of relevant factors on the effectiveness of EVT in patients above 80 years of age. Morbidity and mortality after both IVT and EVT strategies significantly influence the outcomes in both healthy and disabled patients at baseline. Better identification of patients not benefiting from IVT would optimize the selective use of EVT thereby improving its effectiveness.

MR Angiography Screening and Surveillance for Intracranial Aneurysms in Autosomal Dominant Polycystic Kidney Disease: A Cost-effectiveness Analysis.

Background Autosomal dominant polycystic kidney disease (ADPKD) affects one in 400 to one in 1000 individuals; 10%-11% of these individuals have intracranial aneurysms. The frequency and patterns of screening for intracranial aneurysms have not been defined. Purpose To evaluate different MR angiography screening and surveillance strategies for unruptured intracranial aneurysms in patients with ADPKD. Materials and Methods A Markov decision-analytic model was constructed accounting for both costs and outcomes from a societal perspective. Five different management strategies were evaluated: (a) no screening for intracranial aneurysm, (b) one-time screening with annual MR angiography follow-up in patients with intracranial aneurysm, (c) MR angiographic screening every 5 years with endovascular treatment in detected intracranial aneurysm, (d) MR angiography screening every 5 years with annual MR angiography follow-up in patients with intracranial aneurysm, and (e) MR angiography screening every 5 years with biennial follow-up in patients with intracranial aneurysm. One-way, two-way, and probabilistic sensitivity analyses were performed. Results Base case calculation shows that MR angiography screening of patients with ADPKD every 5 years and annual follow-up in patients with detected intracranial aneurysm is the optimal strategy (cost, $19 839; utility, 25.86 quality-adjusted life years), which becomes more favorable as the life expectancy increases beyond 6 years. The conclusion remains robust in probabilistic and one-way sensitivity analyses. When the prevalence of intracranial aneurysms is greater than 10%, annual rupture risk is 0.35%-2.5%, and the rate of de novo aneurysm detection is lower than 1.8%, MR angiography screening every 5 years with annual MR angiography follow-up is the favorable strategy. Conclusion Screening for intracranial aneurysms with MR angiography in patients with autosomal dominant polycystic kidney disease is cost-effective. Repeat screening every 5 years should be performed after a negative initial study. Annual surveillance MR angiography is optimal in patients with detected, incidental intracranial aneurysm, and treatment may be considered in patients with growing, high-risk aneurysms. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Anzai in this issue.

Management of Unruptured Intracranial Aneurysms in Older Adults: A Cost-effectiveness Analysis.

Background Unruptured intracranial aneurysms (UIAs) are relatively common and are being increasingly diagnosed, with a significant proportion in older patients (˃ 65 years old). Serial imaging is often performed to assess change in size or morphology of UIAs since growing aneurysms are known to be at high risk for rupture. However, the frequency and duration of surveillance imaging have not been established. Purpose To evaluate the cost-effectiveness of routine treatment (aneurysm coil placement) versus four different strategies for imaging surveillance of UIAs in adults older than 65 years. Materials and Methods A Markov decision-analytic model was constructed from a societal perspective. Age-dependent input parameters were obtained from published literature. Analysis included adults older than 65 years, with incidental detection of UIA and no prior history of subarachnoid hemorrhage. Five different management strategies for UIAs in older adults were evaluated: (a) annual MR angiography, (b) biennial MR angiography, (c) MR angiography every 5 years, (d) coil placement and follow-up, and (e) limited MR angiography follow-up for the first 2 years after detection only. Outcomes were assessed in terms of quality-adjusted life-years (QALYs). Probabilistic, one-way, and two-way sensitivity analyses were performed. Results Imaging follow-up for the first 2 years after detection is the most cost-effective strategy (cost = $24 572, effectiveness = 13.73 QALYs), showing the lowest cost and highest effectiveness. The conclusion remains robust in probabilistic and one-way sensitivity analyses. Time-limited imaging follow-up remains the optimal strategy when the annual growth rate and rupture risk of growing aneurysms are varied. If annual rupture risk of nongrowing aneurysms is greater than 7.1%, coil placement should be performed directly. Conclusion Routine preventive treatment or periodic, indefinite imaging follow-up is not a cost-effective strategy in all adults older than 65 years with unruptured intracranial aneurysms. More aggressive management strategies should be reserved for patients with high risk of rupture, such as those with aneurysms larger than 7 mm and those with aneurysms in the posterior circulation. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Cloft in this issue.