To assess key trends, strengths, and gaps in validation studies of the Food and Drug Administration (FDA)-regulated imaging-based artificial intelligence/machine learning (AI/ML) algorithms.
We ...audited publicly available details of regulated AI/ML algorithms in imaging from 2008 until April 2021. We reviewed 127 regulated software (118 AI/ML) to classify information related to their parent company, subspecialty, body area and specific anatomy type, imaging modality, date of FDA clearance, indications for use, target pathology (such as trauma) and findings (such as fracture), technique (CAD triage, CAD detection and/or characterization, CAD acquisition or improvement, and image processing/quantification), product performance, presence, type, strength and availability of clinical validation data. Pertaining to validation data, where available, we recorded the number of patients or studies included, sensitivity, specificity, accuracy, and/or receiver operating characteristic area under the curve, along with information on ground-truthing of use-cases. Data were analyzed with pivot tables and charts for descriptive statistics and trends.
We noted an increasing number of FDA-regulated AI/ML from 2008 to 2021. Seventeen (17/118) regulated AI/ML algorithms posted no validation claims or data. Just 9/118 reviewed AI/ML algorithms had a validation dataset sizes of over 1000 patients. The most common type of AI/ML included image processing/quantification (IPQ; n = 59/118), and triage (CADt; n = 27/118). Brain, breast, and lungs dominated the targeted body regions of interest.
Insufficient public information on validation datasets in several FDA-regulated AI/ML algorithms makes it difficult to justify clinical applications since their generalizability and presence of bias cannot be inferred.
Objective
To assess the lesion detection performance of an abbreviated MRI (AMRI-M) protocol consisting of ultrafast SE T2W, DWI, and T1W-HBP at 20 min for colorectal liver metastasis (CRLM) ...surveillance.
Methods
In this Institutional Review Board (IRB)–approved retrospective study, gadoxetic acid–enhanced MRI scans of 57 patients (43 with pathologically proven CRLMs) were assessed. Two readers independently evaluated two sets of images per patient and commented on the number, location, and size of liver lesions. Set 1 included ultrafast spin-echo (SE) T2-weighted (T2W) + T1-weighted (T1W) hepatobiliary phase (HBP) at 20 min sequences + diffusion-weighted imaging (DWI), and set 2 consisted of the standard MRI protocol. A maximum of 10 lesions per patient were recorded. Cohen’s kappa analysis, sensitivity, areas under the curve (AUCs), and the MRI cost analysis of the AMRI-M protocol were assessed.
Results
Between 198 and 209 lesions were assessed with each set of images. The inter-observer agreement for the abbreviated protocol was reported excellent (
κ
= 0.91). The sensitivity and AUCs for the lesion characterization of AMRI-M protocol were very high (over 90%) for both readers. No statistically significant differences in sensitivity (assessed by mixed-effects logistic regression) and AUCs for lesion characterization (by ROC regression) were found between both protocols. The AMRI-M acquisition time was estimated to be less than 10 min, which translated into 59% cost of standard MRI.
Conclusion
Our proposed AMRI-M protocol (ultrafast SE T2W, DWI, and T1W-HBP at 20 min) is fast, low-cost alternative to the standard MRI protocol and has a high lesion detection performance.
Key Points
• Gadoxetic acid–enhanced protocol has increased the accuracy, sensitivity, and specificity of MRI for detecting colorectal liver metastases.
• Our proposed abbreviated MRI protocol is fast, low-cost alternative compared with the standard MRI protocol and has a high lesion detection performance.
• Adoption of our protocol may translate to substantial savings for patients and payers.
Inflammatory hepatocellular adenoma (HCA) is a recently categorized entity of hepatocellular neoplasms. We investigated whether gadoxetic acid-enhanced MRI can distinguish inflammatory HCA from focal ...nodular hyperplasia (FNH).
From January 1, 2009, through January 1, 2013, gadoxetic acid-enhanced MRI examinations from two institutions were reviewed for HCA, with specific histologic features of inflammatory HCA. Biopsy and resection slides were reviewed, and immunohistochemistry for glutamine synthetase was performed in a subset to confirm the initial diagnosis.
A total of 10 possible cases of inflammatory HCA were identified in the pathology database. On the basis of glutamine synthetase staining performed for this study, three cases were rediagnosed as FNH and thus were excluded from the study. Therefore, a total of seven patients with inflammatory HCA were identified. On gadoxetic acid-enhanced MRI, four of these patients had classic features of FNH (group A, FNH mimics), and three had imaging features suggestive of HCA (group B, typical inflammatory HCA). Imaging features that were considered diagnostic of FNH included isointense or minimal T2 hyperintensity, arterial enhancement, and diffuse hyperintensity on hepatobiliary phase. Three of the four patients with FNH mimics had slides available for pathologic rereview, and the diagnosis of inflammatory HCA was supported by glutamine synthetase immunohistochemistry findings. The pathology reports of the remaining four cases were rereviewed and were also found to have features consistent with inflammatory HCA.
Inflammatory HCA can mimic FNH on MRI, including hepatobiliary phase hyperintensity. Moreover, conventional pathology using histopathology alone may lead to misclassification of inflammatory HCA.
Tourists are easy targets for terrorist activities, especially with the rise of lone wolf attacks. Drawing on the example of the 2015 Sousse (Tunisia) shootings, and using a conceptual framework ...informed by tourist security, terrorism risk management including terrorism risk assessment, communication and due care, we analyse the management of the terror induced security risks, and the factors influencing this process. This is achieved through a first-in-the field tourism study that applies narrative analysis to legal discourse. The study reveals that tourist security was compromised by a lack of terrorism risk communication, poor policing, and by limited integration of counter-terrorism strategies, particularly the inadequate implementation of environmental mitigation. We discuss the implications for terrorism risk assessment, management and communication and consider key propositions around tourist security responsibilities (e.g. due care). Future avenues for research are highlighted.
•Examines the relationships between terrorism risk management, tourist security and due care•Explore the management of terror-induced security risks•Applies a novel and under-utilised approach to narrative analysis•Reveals several failings relating to terrorism risk assessment, management and communication•Contribute to a research gap on terrorism risk management, tourist security and due care in the context of lone wolf attacks
This paper seeks to contribute to the debate surrounding the applicability of the resort cycle by testing the model in the context of seaside resort tourism along the south coast of Britain. A brief ...review of the resort cycle is followed by discussion which focuses on the main methodological problems and limitations. In the second part of this paper, using the resort cycle as the broad research framework, an attempt is made to validate the model empirically, drawing upon the experience of a particular resort: Torbay, one of the most well-established seaside resorts in the UK. The results presented here reinforce the importance of ‘unit of analysis’ and highlight the difficulty of operationalizing the model. In addition, the study findings reveal the critical role of regeneration in continued resort evolution.
► Coexistence of relational and essentialist interpretations of place distinctiveness. ► Its use as a tool for extending a resort’s reach. ► Potential value of relational spatiality to resort ...planners and managers. ► Theoretical value of relational spatiality to managing globalisation.
This study examines the extent to which relational spatiality is captured within coastal resort restructuring visions drawing on a detailed examination of Newquay, UK. It outlines the relevance of relational spatiality for spatial planning generally and coastal resort restructuring specifically. Then, utilising Healey’s (2004) conceptualisations of space and place, and employing content analysis of selected tourism strategising documents, it explores the treatment of space and place in Newquay’s visions for restructuring. It reveals the co-existence of Essentialist and Relational approaches to spatial planning, with greater emphasis placed on the former, whilst the latter is used primarily as a tool through which to extend the resort’s reach. Some implications for coastal resort restructuring in Newquay and elsewhere are highlighted.
► Examines the spatial distribution of the impacts of first round transactions. ► Assesses the extent of household and firm integration with the local economy. ► Enhances understanding of the role ...and functioning of English seaside resorts. ► Highlights the importance of context. ► Proposes an alternative method for assessing resort economies.
The internal dynamics of English seaside resorts are poorly understood. Drawing on the examples of two English coastal resorts, and through the implementation of business and household surveys, this study investigates their role and economic functioning. More specifically, it examines the spatial distribution of direct economic linkages within and between these resorts and their hinterlands, and assesses the extent to which households and firms are integrated into the local economy. Resort economies were found to provide a focal point for the purchase and sale of low order goods and services. A number of factors were also found to influence the extent to which households and businesses were integrated with the local economy, and some theoretical and practical implications are highlighted.
This paper evaluates the theoretical insights provided by Butler's resort cycle and the restructuring thesis, and it explores two theoretical relationships that may be drawn between these two ...constructs. The theme is considered in the context of mass tourism coastal resorts generally and of three English seaside resorts specifically, and some important issues are highlighted, relating to decline and restructuring. These issues include the suggestion that resort decline is not necessarily associated with the course of the lifecycle or a particular capitalist phase, but is the outcome of interactions between internal and external forces, and that restructuring must incorporate a greater appreciation of place distinctiveness.
La restructuration du tourisme de bord de mer: le cycle de vie des stations balnéaires. Cet article évalue les perspectives théoriques qui sont offertes par le cycle des stations de Butler et la thèse de la restructuration, et il examine deux liens qui peuvent se voir entre ces deux constructions. Le sujet est considéré dans le contexte du tourisme de masse des stations balnéaires en général et de trois stations de bord de mer en Angleterre en particulier, en soulignant quelques questions importantes qui sont liées au déclin et à la restructuration. Ces questions comprennent la suggestion que le déclin d'une station n'est pas nécessairement lié au cours du cycle de vie ou à une phase capitaliste particulière, étant plutôt le résultat des interactions entre des forces intérieures ou extérieures, et que la restructuration doit incorporer une plus grande appréciation du caractère distinctif du lieu.
Changes to legal and social environments have contributed to the expansion of the disabled tourism market. However, despite this growth, within tourism there is a distinct lack of research of this ...niche market, and in particular of the barriers which impede or prevent those with disabilities from participating in tourism. This study addresses this lacuna by exploring the relationships between three inter-related concepts, these being: (1) travel constraints including its three sub-dimensions, these being intrinsic, environmental, and interactive; (ii) learned helplessness; and, (iii) intention to travel. This is attempted through a structured survey targeted at a sample of disabled Korean travelers (
N
=
301). The results revealed that the three sub-dimensions of constraints exerted no significant influence (
p
<
.05) on travel intentions, though two of the three dimensions (intrinsic and environmental) were found to be statistically significantly associated with learned helplessness. This latter variable, in turn provided a statistically significant negative influence (
p
<
.05) on intention to travel. The theoretical and practical implications of these results are discussed, and some avenues for future research are highlighted.
► Learned helplessness mediated between travel constraints and intention to travel. ► Learned helplessness significantly influenced travel constraints and travel intention. ► Perceived helplessness were influenced by intrinsic and environmental constraints. ► Greater understanding of the concept is required across different disability types. ► Re-visiting disability legislation and empowering the disabled must be considered.
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