DSpace Collection:

Segmentation method comparison for baseline [18F]FDG PET-CT in follicular lymphoma patients

2026-01-01T00:00:00Z

Title: Segmentation method comparison for baseline [18F]FDG PET-CT in follicular lymphoma patients Author(s): Njiman, Anouk D. M.; Kurch, Lars; [und viele weitere] Abstract: Background Follicular lymphoma (FL) is the second most common subtype of non-Hodgkin lymphoma. Currently, [18F]FDG PET-CT is used for staging, response evaluation, and remission assessment. While advances in quantitative PET-CT are promising for prognostic assessment, they depend on reproducible tumor delineation. Various segmentation methods have been proposed, but their application to FL PET is less established, despite known differences in uptake patterns across lymphoma subtypes. This study aims to evaluate the performance of several single-threshold and multi-threshold methods for FL [18F]FDG PET-CT lesion segmentation on segmentation quality, interobserver variability, and ease-of-use. Methods Baseline PET-CT data of 25 second-line FL patients from the HOVON110 trial and 12 first-line FL patients from the PETAL trial were selected. Two observers applied 13 different semi-automatic methods, of which six used a single threshold and seven combined thresholds (multi-threshold). Methods include, SUV threshold methods, an AI-based method, majority vote and lesion-based selection methods. The segmentation process comprises four steps: step 1 and 2 involved generating a preselection, while step 3 and 4 applied an automatic method followed by manual adjustments. To assess segmentation quality, both observers gave a score (1–3) ranging from undersegmentation to oversegmentation. For interobserver variability, the difference in total metabolic tumor volume between observers was determined. The ease-of-use was assessed based on manually added and removed volume in step 4. Results A total of 962 segmentations were made by two observers. Differences in results between the methods were limited across all characteristics, indicating an overall satisfactory performance of all methods. The multi-threshold method scored better for segmentation quality in comparison to single-threshold methods, indicating less under- or oversegmentation. The single-threshold method SUV4.0 demonstrated lower median (0.3 mL) and inter quartile range (2.0 mL) concerning interobserver variability in comparison to lesion-based methods. Conclusion Among the single threshold methods, SUV4.0 is preferred regarding easeof- use, observer variability and segmentation quality. While the multi-threshold lesionbased methods showed the a higher segmentation quality, SUV4.0 has the benefit of easy implementation, wide availability and is in-line with the currently set benchmark for lymphoma PET analysis. We identified SUV4.0 and a lesion-based method as the candidate methods preferred for further clinical performance evaluation.

Blood-based analysis of different tau variants in patients with multiple traumatic injuries

2026-01-01T00:00:00Z

Title: Blood-based analysis of different tau variants in patients with multiple traumatic injuries Author(s): Halbgebauer, Rebecca; Otto, Markus; [und viele weitere] Abstract: IMPORTANCE With blood-based phosphorylated tau biomarkers soon to be used for diagnosis of Alzheimer disease, analyzing tau levels in other conditions could enhance biomarker interpretability. Moreover, mechanisms of tau release into circulation remain unclear. OBJECTIVE To evaluate concentrations of phosphorylated and nonphosphorylated tau variants in the blood of patients with multiple traumatic injuries on days 0, 1, 5, and 10 and investigate biological processes driving tau release. DESIGN, SETTING, AND PARTICIPANTS This multiple-trauma cohort (injury severity score, 18) included 45 severely injured patients with (n = 27) and without (n = 18) moderate-to-severe traumatic brain injury on emergency computed tomographic imaging. Controls consisted of 24 healthy volunteers. Participants were recruited from December 1, 2013, to October 31, 2022. Blood samples were analyzed for brain-derived tau (BD-tau), total tau (t-tau), and phosphorylated tau 217 (p-tau217) and 231 (p-tau231) levels. Associations among tau concentrations, clinical data, and outcome (eg, Glasgow Coma Scale [GCS] score) were assessed. Data were analyzed from March 1, 2023, to September 30, 2024. EXPOSURES Serum BD-tau, t-tau, p-tau217, and p-tau231 levels. RESULTS A total of 214 serum samples were analyzed. Median age of the 45 patients was 48 (IQR, 33-60) years (35 [77.8%] male); median age of the 24 controls, 43 (IQR, 28-50) years (16 [66.7%] male). Median serum levels of tau variants were increased in patients with multiple traumatic injuries at day 0 compared with controls (t-tau: 43 [IQR, 21-95] vs 3 [IQR, 3-5] pg/mL; BD-tau: 78 [IQR, 30-343] vs 2 [IQR, 2-3] pg/mL; p-tau231: 61 [IQR, 21-79] vs 2 [IQR, 1-3] pg/mL; all, P < .001). Only median BD-tau levels remained elevated until day 10 (day 1, 25 [IQR, 14-69] pg/mL; day 5, 9 [IQR, 4-15] pg/mL; day 10, 8 [IQR, 4-18] pg/mL). Median tau levels at admission were higher in patients with lower GCS scores (BD-tau: 107 [ IQR, 59-838] vs 33 [IQR, 24-78] pg/mL [P = .01]; p-tau231: 76 [IQR, 36-114] vs 28 [IQR, 9–63] pg/mL [P = .02]). Elevated median tau levels were also observed in patients with hemorrhagic shock vs those without shock (eg, BD-tau on day 0: 113 [IQR, 78-378] vs 31 [IQR, 24-61] pg/mL; P = .002) and in nonsurvivors vs survivors with uncomplicated courses (eg, BD-tau on day 1: 92 [IQR, 22-527] vs 16 [IQR, 7-23] pg/mL; P = .009). CONCLUSIONS AND RELEVANCE In this exploratory study among a cohort of patients with multiple traumatic injuries, levels of tau variants reflected both direct and indirect neurological injury, with BD-tau showing the most persistent elevation in the acute phase.

Spatio-temporal HYDRUS-1D soil water balance simulations as support for precision irrigation in North-Eastern Germany

2026-01-01T00:00:00Z

Title: Spatio-temporal HYDRUS-1D soil water balance simulations as support for precision irrigation in North-Eastern Germany Author(s): Wenzel, Jan Lukas; Conrad, Christopher; Mahmood, Talha; Kunz, Matthias; Volk, Martin; Pöhlitz, Julia Abstract: Accurate spatio-temporal information on the soil water balance is critical for an efficient and sustainable irrigation. Large effort requirements limit the applicability of complex simulations for precision irrigation. The spatially distributed application of one-dimensional models can reconcile the need for precise soil water balance simulations with the complexity of root-zone water flow processes. This study uses HYDRUS-1D to simulate the daily depth-specific (0 cm to 60 cm, in 10 cm increments) soil water balance from 1st April to 30th September 2021 (2022). Simulations at 70 m spatial resolution covered a 1600 ha farm in Mecklenburg-Western Pomerania, Germany. Results were validated against in-situ soil water content (SWC) and two remotely-sensed SWC data sets (“Soil Moisture Active Passive”, SMAP; Sentinel-1, S1-SWC). Further analysis explored crop-specific irrigation efficiencies and potential farm-scale water savings. Spatially distributed HYDRUS-1D simulations showed good accuracy compared to in-situ SWC (RMSEmean = 0.020 m3 m􀀀 3; MAEmean = 0.017 m3 m􀀀 3; R2mean = 0.676; bias = 􀀀 0.008 m3 m􀀀 3). The agreement with remotely-sensed SWC was moderate to weak (RMSEmean = 0.059 (0.150) m3 m􀀀 3, MAEmean = 0.049 (0.123) m3 m􀀀 3, R2mean = 0.208 (0.141), mean bias = 0.021 (0.108) m3 m􀀀 3 for SMAP (S1-SWC)). Irrigation efficiencies were 65.0 % (potato), 47.3 % (wheat), 40.5 % (rye), and 58.2 % (sugar beet). Potential water savings amounted to 87,006.9 m³ (11.2 % of total irrigation water; 2021) and 71,396.6 m³ (10.4 %; 2022). The proposed approach reduces the trade-offs between accurately representing the soil water balance in the root-zone and keeping the practical effort reasonable.

Long-term beta blocker prescribing after myocardial infarction in European primary care (PRACTITIONER)

2026-01-01T00:00:00Z

Title: Long-term beta blocker prescribing after myocardial infarction in European primary care (PRACTITIONER) Author(s): Zangger, Martina; Jungo, Katharina Tabea; Adler, Limor; Assenova, Radost; Batic-Mujanovic, Olivera; Bracchitta, Luigi; Brütting, Christine; Buczkowski, Krzysztof; Danilenko, Jelena; Erber, Patrick; Gefaell Larrondo, Ileana; Ilkov, Oksana; Javorska, Katerina; Jennings, Aisling A.; Johannessen, Tonje R.; Koskela, Tuomas; Kurpas, Donata; Lazić, Vanja; Mannheimer, Stina; Moussa, Mahmoud; Seifert, Martin; Taraj, Deona; Torzsa, Peter; Viegas Dias, Catarina; Zelko, Erika; Gencer, Baris; Streit, Sven Abstract: Background The long-term use of beta blockers after myocardial infarction in patients with preserved ventricular function is debated. General practitioners (GPs) often decide whether to continue or discontinue long-term medications, yet little is known about how they apply evolving evidence to clinical prescribing decisions. Objective To assess whether GPs are willing to deprescribe beta blockers post myocardial infarction with preserved left ventricular function and to identify factors associated with deprescribing decisions. Design Cross-sectional online survey using case vignettes, conducted between July 2023 and October 2024 in primary care settings in 24 sites across 20 European countries. Participants Practicing GPs recruited through convenience sampling at each site. Main measures The primary outcome was whether the GP chose to deprescribe beta blockers in the vignettes. Adjusted risk ratios for the association between GP characteristics and the decision to deprescribe were estimated using Poisson regression with generalized estimating equations and robust standard errors, accounting for clustering at the GP and country level. Key results 604 GPs participated in the survey (median [IQR] age, 44.0 [35.0-54.8] years; 364 [60.3%] female), 89.2% deprescribed beta blockers in at least one vignette. The likelihood of deprescribing increased with time since myocardial infarction (adjusted risk ratio [RR] = 1.28; 95% CI 1.21–1.36 after 5 years; RR = 1.78; 95% CI 1.66–1.90 after 10 years vs. 3 months) and with side effects (RR = 1.76; 95% CI 1.66–1.88). More years of clinical experience were associated with a lower likelihood of deprescribing (RR = 0.86; 95% CI 0.77–0.95 for most vs. least experienced). Conclusions In this cross-national vignette study, most GPs were willing to deprescribe beta blockers after myocardial infarction in patients with preserved left ventricular function, particularly when time had passed and side effects were present. These findings suggest that GPs are open to applying evolving evidence on beta blocker discontinuation in clinical care.