Systematic Review of Health Economic Evaluations Focused on Artificial Intelligence in Healthcare: The Tortoise and the Cheetah.

OBJECTIVES: This study aimed to systematically review recent health economic evaluations (HEEs) of artificial intelligence (AI) applications in healthcare. The aim was to discuss pertinent methods, reporting quality and challenges for future implementation of AI in healthcare, and additionally advise future HEEs. METHODS: A systematic literature review was conducted in 2 databases (PubMed and Scopus) for articles published in the last 5 years. Two reviewers performed independent screening, full-text inclusion, data extraction, and appraisal. The Consolidated Health Economic Evaluation Reporting Standards and Philips checklist were used for the quality assessment of included studies. RESULTS: A total of 884 unique studies were identified; 20 were included for full-text review, covering a wide range of medical specialties and care pathway phases. The most commonly evaluated type of AI was automated medical image analysis models (n = 9, 45%). The prevailing health economic analysis was cost minimization (n = 8, 40%) with the costs saved per case as preferred outcome measure. A total of 9 studies (45%) reported model-based HEEs, 4 of which applied a time horizon >1 year. The evidence supporting the chosen analytical methods, assessment of uncertainty, and model structures was underreported. The reporting quality of the articles was moderate as on average studies reported on 66% of Consolidated Health Economic Evaluation Reporting Standards items. CONCLUSIONS: HEEs of AI in healthcare are limited and often focus on costs rather than health impact. Surprisingly, model-based long-term evaluations are just as uncommon as model-based short-term evaluations. Consequently, insight into the actual benefits offered by AI is lagging behind current technological developments.

Strength testing of low-cost 3D-printed transtibial prosthetic socket.

Measurement and production of traditional prosthetic sockets are time-consuming, labor-intensive, and highly dependent on the personnel involved. An alternative way to make prostheses is using computer-aided design (CAD) and computer-aided manufacturing (CAM). Fused Filament Fabrication (FFF) may be an alternative to make low-cost prosthetic sockets. This study investigates the tensile properties of potential printing materials suitable for FFF according to ISO527 (Standard Test Method for Tensile Properties of Plastics). To ensure that FFF-printed sockets are safe for patient usage, the structural integrity of the 3D-printed prosthesis will be investigated according to ISO10328 (International Standard Structural Testing of Lower Limb Prostheses). Tough PLA was the most suitable print material according to ISO 527 testing. The Tough PLA printed socket completed 2.27 million cycles and a static test target value of 4025 N. Future research remains necessary to continue testing new potential materials, improve print settings, and improve the socket design for the production of FFF-printed transtibial prosthetic sockets. FFF using Tough PLA can be used to create transtibial prostheses that almost comply with the International Standard for Structural Testing of Lower Limb Prostheses.

Pioneering low-cost 3D-printed transtibial prosthetics to serve a rural population in Sierra Leone - an observational cohort study.

BACKGROUND: There is a huge unmet global need for affordable prostheses. Amputations often happen in Sierra Leone due to serious infections, complex wounds, traffic accidents and delayed patient presentation to the hospital. However, purchasing a prosthesis is still beyond reach for most Sierra Leonean amputees. METHOD: We applied computer-aided design (CAD) and computer-aided manufacturing (CAM) to produce low-cost transtibial prosthetic sockets. In February and March 2020, eight participants received a 3D printed transtibial prosthesis in the village of Masanga in Tonkolili district, Sierra Leone. Research was performed using questionnaires to investigate the use, participants' satisfaction, and possible complications related to the prostheses. Questionnaires were conducted prior to production of the prosthesis and five to six weeks after fitting the prosthesis. A personal short-term goal was set by the participants. FINDINGS: Competitively priced and fully functional prostheses were produced locally. After six weeks, all participants were still wearing the prosthesis and six of the eight participants reached their personal rehabilitation goals. Using their prostheses, all participants were no longer in need of their crutches. INTERPRETATION: We have come a step closer to the production of low-cost prostheses for low-and middle-income countries (LMICs). The goal of our project is to perform long-term follow-up and to refine our concept of 3D printed prostheses for LMICs to provide practical solutions for a global health need unmet to date. FUNDING: € 15,000 was collected during a crowdfunding campaign in collaboration with the Dutch Albert Schweitzer Fund. Internship allowance for MvdS was obtained from the University of Twente. 3D-scanner, 3D-printer, and printing material were donated by Ultimaker BV and Shining 3D.

In vitro performance of echoPIV for assessment of laminar flow profiles in a carotid artery stent.

Purpose: Detailed blood flow studies may contribute to improvements in carotid artery stenting. High-frame-rate contrast-enhanced ultrasound followed by particle image velocimetry (PIV), also called echoPIV, is a technique to study blood flow patterns in detail. The performance of echoPIV in presence of a stent has not yet been studied extensively. We compared the performance of echoPIV in stented and nonstented regions in an in vitro flow setup. Approach: A carotid artery stent was deployed in a vessel-mimicking phantom. High-frame-rate contrast-enhanced ultrasound images were acquired with various settings. Signal intensities of the contrast agent, velocity values, and flow profiles were calculated. Results: The results showed decreased signal intensities and correlation coefficients inside the stent, however, PIV analysis in the stent still resulted in plausible flow vectors. Conclusions: Velocity values and laminar flow profiles can be measured in vitro in stented arteries using echoPIV.

State-of-the-art Intraoperative Imaging Technologies for Prostate Margin Assessment: A Systematic Review.

CONTEXT: The main challenge in radical prostatectomy is complete excision of malignant tissue, while preserving continence and erectile function. Positive surgical margins (PSMs) occur in up to 38% of cases, are associated with tumour recurrences, and may result in debilitating additional therapies. Despite surgical developments for prostate cancer (PCa), no technology is yet implemented to assess surgical margins of the entire prostatic surface intraoperatively. OBJECTIVE: The aim of this systematic review is to provide an overview of novel imaging methods developed for intraoperative margin assessment in PCa surgery, which are compared with standard postoperative histopathology. EVIDENCE ACQUISITION: A literature search of the last 10 yr was conducted in the Scopus, PubMed, and Embase (Ovid) databases. Eligible articles had to report the PSM rate according to their intraoperative margin assessment technology in comparison with standard histopathology. EVIDENCE SYNTHESIS: The search resulted in 616 original articles, of which 11 were included for full-text review. The main technical developments in PCa margin assessment included optical coherence tomography, photodynamic diagnosis with 5-aminolevulinic acid, spectroscopy, and enhanced microscopy. These techniques are described and their main advantages, limitations, and applications in the clinical setting are discussed. CONCLUSIONS: Several imaging methods are suggested in literature for the detection of positive margins during PCa surgery. Despite promising qualifications of the mentioned technologies, many struggle to find implementation in the clinic. Surgical conditions hampering the signal, long imaging times, and comparison with histopathology are mutual challenges. The next step towards reduction of PSMs in PCa surgery includes evaluation of these technologies in large clinical trials. PATIENT SUMMARY: In this review, new technologies are reported that can assist the surgeon by detecting insufficient removal of all tumorous tissue during surgery, instead of the standard postoperative histopathological assessment. Currently, it is not clear whether these technologies improve the patient outcome directly; however, the review shows potential future implementations.

(In)comparability of Carotid Artery Stent Characteristics: A Systematic Review on Assessment and Comparison with Manufacturer Data.

PURPOSE: Carotid stent (CS) characteristics, such as radial force, scaffolding and flexibility, are continuously modified by stent manufacturers aiming to improve stent performance. Since manufacturers' definitions and assessment methods are not disclosed, it is unknown how characteristics of different CSs relate to each other or to published literature. We examined in vitro methodological techniques used to measure CS characteristics and assessed comparability between published papers and outcomes as provided by the manufacturers. METHODS: A systematic review was conducted in MEDLINE, Embase, Cochrane, and Scopus databases. Studies reporting on in vitro investigations of predefined characteristics of CS used in current everyday clinical practice were included. The predefined characteristics were radial force, scaffolding, flexibility, foreshortening, side-branch preservation and visibility. Eight manufacturers of 10 currently used CS were contacted and data on the predefined device characteristics was requested. RESULTS: 12 published articles were included and six stent manufacturers provided data on six stents (two refused to share data). Used methodologies to measure stent characteristics in published literature and manufacturer data varied greatly for all included characteristics except foreshortening. The number of different units of measurement to express outcomes ranged from two for foreshortening to six for radial force. CONCLUSION: A variety of methodologies and outcome measures is used to quantify CS characteristics, which hampers comparisons between published studies and manufacturer data. Future studies are encouraged to synchronize methodologies and outcome measures. Manufacturers are encouraged up to increase transparency of applied testing methodologies and outcomes.

Assessment of Dynamic Change of Coronary Artery Geometry and Its Relationship to Coronary Artery Disease, Based on Coronary CT Angiography.

To investigate the relationship between dynamic changes of coronary artery geometry and coronary artery disease (CAD) using computed tomography (CT). Seventy-one patients underwent coronary CT angiography with retrospective electrocardiographic gating. End-systolic (ES) and end-diastolic (ED) phases were automatically determined by dedicated software. Centerlines were extracted for the right and left coronary artery. Differences between ES and ED curvature and tortuosity were determined. Associations of change in geometrical parameters with plaque types and degree of stenosis were investigated using linear mixed models. The differences in number of inflection points were analyzed using Wilcoxon signed-rank tests. Tests were done on artery and segment level. One hundred thirty-seven arteries (64.3%) and 456 (71.4%) segments were included. Curvature was significantly higher in ES than in ED phase for arteries (p = 0.002) and segments (p < 0.001). The difference was significant only at segment level for tortuosity (p = 0.005). Number of inflection points was significantly higher in ES phase on both artery and segment level (p < 0.001). No significant relationships were found between degree of stenosis and plaque types and dynamic change in geometrical parameters. Non-invasive imaging by cardiac CT can quantify change in geometrical parameters of the coronary arteries during the cardiac cycle. Dynamic change of vessel geometry through the cardiac cycle was not found to be related to the presence of CAD.

Additional value of biomechanical indices based on CTa for rupture risk assessment of abdominal aortic aneurysms.

OBJECTIVE: Biomechanics for rupture risk prediction in abdominal aortic aneurysms (AAA) are gaining popularity. However, their clinical applicability is still doubtful as there is lack of standardization. This study evaluates the added value of biomechanical indices in rupture risk assessment. METHODS: This study included 175 asymptomatic, 11 sAAA and 45 ruptured aneurysms. 3D-geometries were reconstructed using computer tomography angiographies. Subsequently, finite element models were made to calculate peak wall stress (PWS), peak wall rupture index (PWRI) and the rupture risk equivalent diameter (RRED). The indices were determined with a dedicated software to facilitate standardization. RESULTS: SAAAs showed a trend towards higher PWS, PWRI and RRED compared to asymptomatic AAAs, but PWS (22.0±5.8 vs. 33.4±15.8 N/cm2), PWRI (0.52±0.2 vs. 1.01±0.64), and RRED (65±60 vs. 98±51 mm) were significantly (p = 0.001) higher in ruptured. However, after diameter-matching no significant differences were seen. The ROC-curves for the maximum diameter and all biomechanical indices were similar but it slightly increased when diameter and biomechanical indices were combined. CONCLUSIONS: This study showed no added value for biomechanical indices in AAA rupture risk assessment. Additionally, the difficulty of such an assessment increases. However, as symptomatic aneurysms show a trend towards higher biomechanical indices with similar diameters the indices may provide information about aneurysm growth and development.

Transfer function analysis for the assessment of cerebral autoregulation using spontaneous oscillations in blood pressure and cerebral blood flow.

Cerebral autoregulation (CA) is a key mechanism to protect the brain against excessive fluctuations in blood pressure (BP) and maintain cerebral blood flow. Analyzing the relationship between spontaneous BP and cerebral blood flow velocity (CBFV) using transfer function analysis is a widely used technique to quantify CA in a non-invasive way. The objective of this review was to provide an overview of transfer function techniques used in the assessment of CA. 113 publications were included. This literature showed that there is no gold standard for the execution and implementation of the transfer function. There is a high diversity in settings and criteria used for transfer function analysis. Notable is also the high number of studies which report little on the settings. This disparity makes it difficult to replicate or compare the results of the different studies and further hinders the opportunity to make a distinction between intact and impaired CA in different patient groups. More research on the effects of different implementation techniques on CA results and optimization of the transfer function analysis is urgently needed. Furthermore, international guidelines should be created to inform the minimal description of the applied technique and the interpretation of transfer function outcomes in scientific research.