Chaos and COSMOS-Considerations on QSM methods with multiple and single orientations and effects from local anisotropy.

PURPOSE: Field-to-susceptibility inversion in quantitative susceptibility mapping (QSM) is ill-posed and needs numerical stabilization through either regularization or oversampling by acquiring data at three or more object orientations. Calculation Of Susceptibility through Multiple Orientations Sampling (COSMOS) is an established oversampling approach and regarded as QSM gold standard. It achieves a well-conditioned inverse problem, requiring rotations by 0°, 60° and 120° in the yz-plane. However, this is impractical in vivo, where head rotations are typically restricted to a range of ±25°. Non-ideal sampling degrades the conditioning with residual streaking artifacts whose mitigation needs further regularization. Moreover, susceptibility anisotropy in white matter is not considered in the COSMOS model, which may introduce additional bias. The current work presents a thorough investigation of these effects in primate brain. METHODS: Gradient-recalled echo (GRE) data of an entire fixed chimpanzee brain were acquired at 7 T (350 µm resolution, 10 orientations) including ideal COSMOS sampling and realistic rotations in vivo. Comparisons of the results included ideal COSMOS, in-vivo feasible acquisitions with 3-8 orientations and single-orientation iLSQR QSM. RESULTS: In-vivo feasible and optimal COSMOS yielded high-quality susceptibility maps with increased SNR resulting from averaging multiple acquisitions. COSMOS reconstructions from non-ideal rotations about a single axis required additional L2-regularization to mitigate residual streaking artifacts. CONCLUSION: In view of unconsidered anisotropy effects, added complexity of the reconstruction, and the general challenge of multi-orientation acquisitions, advantages of sub-optimal COSMOS schemes over regularized single-orientation QSM appear limited in in-vivo settings.

[The Significance of Chronic Fatigue in the Post-Covid Consultation and its Consequences for Outpatient Rehabilitation in the Context of Statutory Accident Insurance]. / Die Bedeutung der Chronischen Fatigue in der Post-COVID-Sprechstunde und ihre Konsequenzen für die ambulante Rehabilitation im Kontext der gesetzlichen Unfallversicherung.

OBJECTIVE: The post-COVID consultation (PCC) is offered as part of a comprehensive range of treatment services provided by the statutory accident insurance for post-COVID patients to determine individual recommendations for further care. The aim of the study was to record the main symptoms and the associated restrictions on social and occupational participation in order to derive consequences for outpatient rehabilitation. METHOD: In addition to a medical examination and a psychological consil, numerous assessments were carried out to evaluate the biopsychosocial state of health. 373 female (82.2%) and 81 male patients aged between 40 and 60 years from the professions of health and care services, education and pedagogy participated in the PCC since April 2021. RESULTS: Nearly all patients (98.2%) reported fatigue as a cardinal symptom of their post-COVID complaints, in combination with subjectively experienced limitations in brain functioning in over 73% of cases. The duration of the symptomatology persisted for an average of 14-15 months in both female and male insured persons. Thus, over 85% of the total sample can be classified as cases of chronic fatigue (Fatigue Scale). The severity of fatigue also proportionally affects quality of life (SF-36), feelings of anxiety and depression (HADS), psychological resilience (RS-13), and motor parameters such as maximum grip strength and endurance capacity. 54.3% of the patients also received a suspected mental diagnosis and 38.1% a recommendation for further neuropsychological diagnostics. CONCLUSION: For further treatment of the leading symptom of chronic fatigue, a multimodal and interdisciplinary outpatient rehabilitation is recommended, which should be oriented towards the treatment of the diagnosis of chronic fatigue syndrome (ME/CFS) and thus in particular towards a psychoeducational and rather than a curative therapeutic approach, and should consider aftercare strategies. Confirmed mental disorders and neuropsychological deficits are to be treated in addition.

"Being Simple on Complex Issues" - Accounts on Visual Data Communication about Climate Change.

Data visualizations play a critical role in both communicating scientific evidence about climate change and in stimulating engagement and action. To investigate how visualizations can be better utilized to communicate the complexities of climate change to different audiences, we conducted interviews with 17 experts in the fields of climate change, data visualization, and science communication, as well as with 12 laypersons. Besides questions about climate change communication and various aspects of data visualizations, we also asked participants to share what they think is the main takeaway message for two exemplary climate change data visualizations. Through a thematic analysis, we observe differences regarding the included contents, the length and abstraction of messages, and the sensemaking process between and among the participant groups. On average, experts formulated shorter and more abstract messages, often referring to higher-level conclusions rather than specific details. We use our findings to reflect on design decisions for creating more effective visualizations, particularly in news media sources geared toward lay audiences. We hereby discuss the adaption of contents according to the needs of the audience, the trade-off between simplification and accuracy, as well as techniques to make a visualization attractive.

The Challenge of Interdisciplinarity at the Intersection of Groundwater Management and Visualization Research.

This design study presents an analysis and abstraction of temporal and spatial data, and workflows in the domain of hydrogeology and the design and development of an interactive visualization prototype. Developed in close collaboration with a group of hydrogeological researchers, the interface supports them in data exploration, selection of data for their numerical model calibration, and communication of findings to their industry partners. We highlight both pitfalls and learnings of the iterative design and validation process and explore the role of rapid prototyping. Some of the main lessons were that the ability to see their own data changed the engagement of skeptical users dramatically and that interactive rapid prototyping tools are thus powerful to unlock the advantage of visual analysis for novice users. Further, we observed that the process itself helped the domain scientists understand the potential and challenges of their data more than the final interface prototype.

SunScreen: Visual Fault Detection for Solar-Thermal Systems.

Fault detection is essential to ensure the proper operation of solar-thermal plants. Hence, monitoring personnel frequently analyze the data to detect unusual behavior. While visualization approaches may considerably support the monitoring of personnel during their work, no existing application can yet deal with the multivariate and time-dependent sensor data, or does not fully support the users' workflow. Thus, this work introduces the visual framework SunScreen. It allows users to explore the sensor data, automatically detected anomalies, and system events (e.g., already detected faults and services). The feedback from the users shows that they appreciate the tool and especially its annotation functionality. However, the system-usability-scale (SUS) results indicate that it does not meet all requirements yet.

Exploring the Design Space of Three Criteria Decision Making.

This article presents different interface designs of sliders to support decision-making problems with three criteria. We present an exploration of the design space through an iterative development process with eight prototypes and the results of several evaluation studies with visualization experts and nonexperts. Our findings show three candidates for consideration: a standard ternary triangular slider, a novel circular slider, and a standard basic slider displayed three times. All three were considered intuitive and easy to use. The triangular slider is best for exploration with vague user intuition, the circular slider performs best for preference comparisons, and the parallel slider is best for direct preference setting.

ModEx: a general purpose computer model exploration system.

We present a general purpose visual analysis system that can be used for exploring parameters of a variety of computer models. Our proposed system offers key components of a visual parameter analysis framework including parameter sampling, deriving output summaries, and an exploration interface. It also provides an API for rapid development of parameter space exploration solutions as well as the flexibility to support custom workflows for different application domains. We evaluate the effectiveness of our system by demonstrating it in three domains: data mining, machine learning and specific application in bioinformatics.

Uncover: Toward Interpretable Models for Detecting New Star Cluster Members.

In this design study, we present Uncover, an interactive tool aimed at astronomers to find previously unidentified member stars in stellar clusters. We contribute data and task abstraction in the domain of astronomy and provide an approach for the non-trivial challenge of finding a suitable hyper-parameter set for highly flexible novelty detection models. We achieve this by substituting the tedious manual trial and error process, which usually results in finding a small subset of passable models with a five-step workflow approach. We utilize ranges of a priori defined, interpretable summary statistics models have to adhere to. Our goal is to enable astronomers to use their domain expertise to quantify model goodness effectively. We attempt to change the current culture of blindly accepting a machine learning model to one where astronomers build and modify a model based on their expertise. We evaluate the tools' usability and usefulness in a series of interviews with domain experts.

Flare during tapering of biological DMARDs in patients with rheumatoid arthritis in routine care: characteristics and predictors.

OBJECTIVE: To identify predictors of flare in a 2-year follow-up study of patients with rheumatoid arthritis (RA) in sustained clinical remission tapering towards withdrawal of biological disease-modifying anti-rheumatic drugs (bDMARDs). METHODS: Sustained clinical remission was defined as Disease Activity Score for 28 joints (DAS28)-C reactive protein (CRP) ≤2.6 without radiographic progression for >1 year. bDMARDs were tapered according to a mandatory clinical guideline to two-thirds of standard dose at baseline, half of dose at week 16 and discontinuation at week 32. Prospective assessments for 2 years included clinical evaluation, conventional radiography, ultrasound and MRI for signs of inflammation and bone changes. Flare was defined as DAS28-CRP ≥2.6 with ∆DAS28-CRP ≥1.2 from baseline. Baseline predictors of flare were assessed by logistic regression analyses. RESULTS: Of 142 included patients, 121 (85%) flared during follow-up of which 86% regained remission within 24 weeks after flare. Patients that flared were more often rheumatoid factor positive, had tried more bDMARDs and had higher baseline ultrasound synovitis sum scores than those not flaring. For patients on standard dose, predictors of flare within 16 weeks after reduction to two-thirds of standard dose were baseline MRI-osteitis (OR 1.16; 95% CI 1.03 to 1.33; p=0.014), gender (female) (OR 6.71; 95% CI 1.68 to 46.12; p=0.005) and disease duration (OR 1.06; 95% CI 1.01 to 1.11; p=0.020). Baseline predictors for flare within 2 years were ultrasound grey scale synovitis sum score (OR 1.19; 95% CI 1.02 to 1.44; p=0.020) and number of previous bDMARDs (OR 4.07; 95% CI 1.35 to 24.72; p=0.007). CONCLUSION: The majority of real-world patients with RA tapering bDMARDs flared during tapering, with the majority regaining remission after stepwise dose increase. Demographic and imaging parameters (MR-osteitis/ultrasound greyscale synovitis) were independent predictors of immediate flare and flare overall and may be of importance for clinical decision-making in patients eligible for tapering.

Ultrasound assessment of hands and feet for synovitis at time of first clinical visit markedly reduces time to diagnosis in routine care.

OBJECTIVES: The role of musculoskeletal US (MSUS) in routine care for diagnosing arthritis is not fully elucidated, but US is more sensitive than clinical joint examination for detecting synovitis. Therefore, the use of US may facilitate diagnosis of arthritis. The aim of the study was to assess whether MSUS examination of hands and feet in relation to the first clinical visit had an impact on the time to reach a final diagnosis and the number of clinical follow-up visits needed after first consultation. METHODS: Two cohorts referred to the outpatient arthritis clinic with suspected arthritis were compared with each other, (i) MSUS (October 2017 to June 2018) of hands and feet performed prior to the first clinical visit and (ii) MSUS (November 2016 to June 2017) was performed ad hoc, for the following aspects: time to clinical diagnosis, number of clinical visits needed, and number of US examinations. RESULTS: In total, 163 and 109 patients were included in the MSUS and comparative cohorts, respectively. Adding MSUS to the first clinical visit reduced the time to diagnosis from mean 31 (32.2) days to 12 (17.3) days (P < 0.01). The number of clinical visits needed was reduced from mean 2.8 (1.1) to 2.1 (1.3) (P < 0.01), corresponding to a reduction of 114 visits in the MSUS cohort. A final diagnosis with inflammatory arthritis was found in 76 (47%) of patients in the MSUS cohort vs 29 (27%) in the comparative cohort (P < 0.01). CONCLUSION: In patients referred for suspected arthritis, routine MSUS in relation to the first clinical visit significantly reduces time to diagnosis and number of clinical visits needed to reach a final diagnosis.

embComp: Visual Interactive Comparison of Vector Embeddings.

This article introduces embComp, a novel approach for comparing two embeddings that capture the similarity between objects, such as word and document embeddings. We survey scenarios where comparing these embedding spaces is useful. From those scenarios, we derive common tasks, introduce visual analysis methods that support these tasks, and combine them into a comprehensive system. One of embComp's central features are overview visualizations that are based on metrics for measuring differences in the local structure around objects. Summarizing these local metrics over the embeddings provides global overviews of similarities and differences. Detail views allow comparison of the local structure around selected objects and relating this local information to the global views. Integrating and connecting all of these components, embComp supports a range of analysis workflows that help understand similarities and differences between embedding spaces. We assess our approach by applying it in several use cases, including understanding corpora differences via word vector embeddings, and understanding algorithmic differences in generating embeddings.

Doppler ultrasound predicts successful discontinuation of biological DMARDs in rheumatoid arthritis patients in clinical remission.

OBJECTIVE: To assess the ability of ultrasound to predict successful tapering and successful discontinuation of biological DMARDs (bDMARDs) at the 2-year follow-up in RA patients in sustained remission. METHODS: Patients in sustained remission (DAS28-CRP ≤ 2.6) and with no radiographic progression the previous year tapered bDMARDs according to a standardized regime. A total of 119 of these patients were included in this ultrasound substudy. At baseline, clinical assessment, MRI, X-ray and ultrasound of 24 joints were performed. Ultrasound-detected synovitis was defined and scored 0-3 using the OMERACT scoring system at the joint level for both grey-scale and Doppler activity. Sum scores for each ultrasound modality were calculated for 24 joints at the patient level. The final state of treatment was assessed after 2 years. The predictive value of ultrasound measures for successful tapering and discontinuation at the 2-year follow-up was assessed via logistic regression analyses. RESULTS: Negative IgM-RF [odds ratio (OR) = 0.29, 95% CI: 0.10-0.85; P = 0.024] and lower Doppler sum score of 24 joints (OR = 0.44, 95% CI: 0.15, 0.87; P = 0.014) were independent predictors for successful discontinuation of bDMARDs at the 2-year follow-up. The predictive value of the Doppler sum score was independent of MRI findings. Previous numbers of bDMARDs were predictive of successful tapering (OR = 0.58, 95% CI: 0.35, 0.91; P = 0.018), whereas ultrasound was not. Clinical parameters were not predictive of successful tapering/discontinuation. CONCLUSION: Doppler sum score was an independent predictor for successful discontinuation of bDMARDs at the 2-year follow-up-the odds for achieving successful discontinuation decreased by 56% per one-unit increase in Doppler sum score. Ultrasound could not predict successful tapering.

Using a DAS28-CRP-steered treat-to-target strategy does not eliminate subclinical inflammation as assessed by ultrasonography in rheumatoid arthritis patients in longstanding clinical remission.

BACKGROUND: Subclinical synovitis by ultrasound is a frequent finding in rheumatoid arthritis (RA) patients in remission and has been shown to be related to erosive progression, risk of flare and unsuccessful drug tapering, but it has not been investigated how a DAS28 T2T-steered strategy in routine care affects the presence of subclinical synovitis in RA patients in remission. The aim of the current study was to investigate the presence of ultrasound-detected subclinical inflammation in RA patients in long-term remission receiving either biological or conventional disease-modifying anti-rheumatic drugs (bDMARD/csDMARD) and, finally, to investigate the presence of ultrasound remission using different ultrasound remission criteria. METHODS: Eighty-seven RA patients (42 patients receiving bDMARD and 45 csDMARD) received DAS28-CRP-steered treatment in routine care and had achieved DAS28-CRP-remission for > 1 year without radiographic progression. Twenty-four joints were scored 0-3 by ultrasound (elbows, wrists, knees, ankles, metacarpophalangeal and metatarsophalangeal joints 2-5) for grey-scale synovial hypertrophy (GS) and colour Doppler activity (CD) using the OMERACT scoring system. Ultrasound remission was defined as strict (GS score = 0 and CD score = 0), semi-strict (GS score < 1 and Doppler score = 0) and Doppler remission (Doppler score = 0). RESULTS: No differences between treatment groups were found for GS sum score and Doppler sum score (median (range) 6 (0-19) and 0 (0-12), respectively). A Doppler score > 0 in at least 1 joint was seen in 44%, a GS score > 1 in at least 1 joint in 93% and a GS score > 2 in at least 1 joint in 54% of patients. Strict ultrasound remission was only observed in bDMARD patients (7%; p = 0.01). Thirty-seven per cent were in semi-strict ultrasound remission and 56% in Doppler remission (no significant difference between groups) with similar results across the subgroups of patients who also fulfilled the ACR-EULAR Boolean-, CDAI- and SDAI-remission criteria. CONCLUSIONS: Ultrasound frequently detected subclinical synovitis in RA patients in longstanding DAS28-remission obtained through a DAS28-CRP-steered strategy. This was independent of treatment and applied ultrasound remission criteria. Strict ultrasound remission was rare.

VIS30K: A Collection of Figures and Tables From IEEE Visualization Conference Publications.

We present the VIS30K dataset, a collection of 29,689 images that represents 30 years of figures and tables from each track of the IEEE Visualization conference series (Vis, SciVis, InfoVis, VAST). VIS30K's comprehensive coverage of the scientific literature in visualization not only reflects the progress of the field but also enables researchers to study the evolution of the state-of-the-art and to find relevant work based on graphical content. We describe the dataset and our semi-automatic collection process, which couples convolutional neural networks (CNN) with curation. Extracting figures and tables semi-automatically allows us to verify that no images are overlooked or extracted erroneously. To improve quality further, we engaged in a peer-search process for high-quality figures from early IEEE Visualization papers. With the resulting data, we also contribute VISImageNavigator (VIN, visimagenavigator.github.io), a web-based tool that facilitates searching and exploring VIS30K by author names, paper keywords, title and abstract, and years.

Analysis and comparison of algorithms for the tomographic reconstruction of curved fibres.

We present visual methods for the analysis and comparison of the results of curved fibre reconstruction algorithms, i.e., of algorithms extracting characteristics of curved fibres from X-ray computed tomography scans. In this work, we extend previous methods for the analysis and comparison of results of different fibre reconstruction algorithms or parametrisations to the analysis of curved fibres. We propose fibre dissimilarity measures for such curved fibres and apply these to compare multiple results to a specified reference. We further propose visualisation methods to analyse differences between multiple results quantitatively and qualitatively. In two case studies, we show that the presented methods provide valuable insights for advancing and parametrising fibre reconstruction algorithms, and support in improving their results in characterising curved fibres.

A clinical study to evaluate the cardiopulmonary characteristics of two different anaesthetic protocols for immobilization of healthy chimpanzees (Pan troglodytes).

OBJECTIVE: To characterize the cardiopulmonary characteristics of two different anaesthetic protocols (tiletamine/zolazepam ± medetomidine) and their suitability for the immobilization of healthy chimpanzees undergoing cardiac assessment. STUDY DESIGN: Prospective, clinical, longitudinal study. ANIMALS: Six chimpanzees (Pan troglodytes) aged 4-16 years weighing 19.5-78.5 kg were anaesthetized on two occasions. METHODS: Anaesthesia was induced with tiletamine/zolazepam (TZ) (3-4 mg kg-1) or tiletamine/zolazepam (2 mg kg-1) and medetomidine (0.02 mg kg-1) (TZM) via blow dart [intramuscular (IM)] and maintained with intermittent boluses of ketamine (IV) or zolazepam/tiletamine (IM) as required. The overall quality of the anaesthesia was quantified based on scores given for: quality of induction, degree of muscle relaxation and ease of intubation. The time to achieve a light plane of anaesthesia, number of supplemental boluses needed and recovery characteristics were also recorded. Chimpanzees were continuously monitored and heart rate (HR), pulse rate (PR), respiratory rate (fR) oxygen saturation of haemoglobin (SpO2), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), rectal temperature, mucous membrane colour and capillary refill time recorded. During the first procedure (TZ) animals underwent a 12-channel electrocardiogram (ECG), haematology, biochemistry and cardiac biomarker assessment to rule out the presence of pre-existing cardiovascular disease. A detailed echocardiographic examination was carried out by the same blinded observer during both procedures. Data were compared using Student's paired t-test or Wilcoxon rank tests as appropriate. RESULTS: There was a significant difference for the area under the curves between anaesthetic protocols for HR, SAP, MAP and fR. No significant differences in the echocardiographic measurements were evident. Quality of anaesthesia was significantly better with TZM and no additional boluses were required. The TZ protocol required multiple supplemental boluses. CONCLUSIONS AND CLINICAL RELEVANCE: Both combinations are suitable for immobilization and cardiovascular evaluation of healthy chimpanzees. Further work is required to evaluate the effect of medetomidine in cardiovascular disease.

TreePOD: Sensitivity-Aware Selection of Pareto-Optimal Decision Trees.

Balancing accuracy gains with other objectives such as interpretability is a key challenge when building decision trees. However, this process is difficult to automate because it involves know-how about the domain as well as the purpose of the model. This paper presents TreePOD, a new approach for sensitivity-aware model selection along trade-offs. TreePOD is based on exploring a large set of candidate trees generated by sampling the parameters of tree construction algorithms. Based on this set, visualizations of quantitative and qualitative tree aspects provide a comprehensive overview of possible tree characteristics. Along trade-offs between two objectives, TreePOD provides efficient selection guidance by focusing on Pareto-optimal tree candidates. TreePOD also conveys the sensitivities of tree characteristics on variations of selected parameters by extending the tree generation process with a full-factorial sampling. We demonstrate how TreePOD supports a variety of tasks involved in decision tree selection and describe its integration in a holistic workflow for building and selecting decision trees. For evaluation, we illustrate a case study for predicting critical power grid states, and we report qualitative feedback from domain experts in the energy sector. This feedback suggests that TreePOD enables users with and without statistical background a confident and efficient identification of suitable decision trees.

Vispubdata.org: A Metadata Collection About IEEE Visualization (VIS) Publications.

We have created and made available to all a dataset with information about every paper that has appeared at the IEEE Visualization (VIS) set of conferences: InfoVis, SciVis, VAST, and Vis. The information about each paper includes its title, abstract, authors, and citations to other papers in the conference series, among many other attributes. This article describes the motivation for creating the dataset, as well as our process of coalescing and cleaning the data, and a set of three visualizations we created to facilitate exploration of the data. This data is meant to be useful to the broad data visualization community to help understand the evolution of the field and as an example document collection for text data visualization research.

Predicting the Interactive Rendering Time Threshold of Gaussian Process Models With HyperSlice.

In this paper we present a method for predicting the rendering time to display multi-dimensional data for the analysis of computer simulations using the HyperSlice [36] method with Gaussian process model reconstruction. Our method relies on a theoretical understanding of how the data points are drawn on slices and then fits the formula to a user's machine using practical experiments. We also describe the typical characteristics of data when analyzing deterministic computer simulations as described by the statistics community. We then show the advantage of carefully considering how many data points can be drawn in real time by proposing two approaches of how this predictive formula can be used in a real-world system.

Visualization as Seen through its Research Paper Keywords.

We present the results of a comprehensive multi-pass analysis of visualization paper keywords supplied by authors for their papers published in the IEEE Visualization conference series (now called IEEE VIS) between 1990-2015. From this analysis we derived a set of visualization topics that we discuss in the context of the current taxonomy that is used to categorize papers and assign reviewers in the IEEE VIS reviewing process. We point out missing and overemphasized topics in the current taxonomy and start a discussion on the importance of establishing common visualization terminology. Our analysis of research topics in visualization can, thus, serve as a starting point to (a) help create a common vocabulary to improve communication among different visualization sub-groups, (b) facilitate the process of understanding differences and commonalities of the various research sub-fields in visualization, (c) provide an understanding of emerging new research trends, (d) facilitate the crucial step of finding the right reviewers for research submissions, and (e) it can eventually lead to a comprehensive taxonomy of visualization research. One additional tangible outcome of our work is an online query tool (http://keyvis.org/) that allows visualization researchers to easily browse the 3952 keywords used for IEEE VIS papers since 1990 to find related work or make informed keyword choices.