TY - JOUR A1 - Hoffmann, Jan V. A1 - Janssen, Jan P. A1 - Kanno, Takayuki A1 - Shibutani, Takayuki A1 - Onoguchi, Masahisa A1 - Lapa, Constantin A1 - Grunz, Jan-Peter A1 - Buck, Andreas K. A1 - Higuchi, Takahiro T1 - Performance evaluation of fifth-generation ultra-high-resolution SPECT system with two stationary detectors and multi-pinhole imaging JF - EJNMMI Physics N2 - Background Small-animal single-photon emission computed tomography (SPECT) systems with multi-pinhole collimation and large stationary detectors have advantages compared to systems with moving small detectors. These systems benefit from less labour-intensive maintenance and quality control as fewer prone parts are moving, higher accuracy for focused scans and maintaining high resolution with increased sensitivity due to focused pinholes on the field of view. This study aims to investigate the performance of a novel ultra-high-resolution scanner with two-detector configuration (U-SPECT5-E) and to compare its image quality to a conventional micro-SPECT system with three stationary detectors (U-SPECT\(^+\)). Methods The new U-SPECT5-E with two stationary detectors was used for acquiring data with \(^{99m}\)Tc-filled point source, hot-rod and uniformity phantoms to analyse sensitivity, spatial resolution, uniformity and contrast-to-noise ratio (CNR). Three dedicated multi-pinhole mouse collimators with 75 pinholes each and 0.25-, 0.60- and 1.00-mm pinholes for extra ultra-high resolution (XUHR-M), general-purpose (GP-M) and ultra-high sensitivity (UHS-M) imaging were examined. For CNR analysis, four different activity ranges representing low- and high-count settings were investigated for all three collimators. The experiments for the performance assessment were repeated with the same GP-M collimator in the three-detector U-SPECT\(^+\) for comparison. Results Peak sensitivity was 237 cps/MBq (XUHR-M), 847 cps/MBq (GP-M), 2054 cps/MBq (UHS-M) for U-SPECT5-E and 1710 cps/MBq (GP-M) for U-SPECT\(^+\). In the visually analysed sections of the reconstructed mini Derenzo phantoms, rods as small as 0.35 mm (XUHR-M), 0.50 mm (GP-M) for the two-detector as well as the three-detector SPECT and 0.75 mm (UHS-M) were resolved. Uniformity for maximum resolution recorded 40.7% (XUHR-M), 29.1% (GP-M, U-SPECT5-E), 16.3% (GP-M, U-SPECT\(^+\)) and 23.0% (UHS-M), respectively. UHS-M reached highest CNR values for low-count images; for rods smaller than 0.45 mm, acceptable CNR was only achieved by XUHR-M. GP-M was superior for imaging rods sized from 0.60 to 1.50 mm for intermediate activity concentrations. U-SPECT5-E and U-SPECT+ both provided comparable CNR. Conclusions While uniformity and sensitivity are negatively affected by the absence of a third detector, the investigated U-SPECT5-E system with two stationary detectors delivers excellent spatial resolution and CNR comparable to the performance of an established three-detector-setup. KW - small-animal imaging KW - SPECT KW - mouse KW - ollimator KW - post-reconstruction filtering Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230361 VL - 7 ER - TY - JOUR A1 - Janssen, Jan P. A1 - Hoffmann, Jan V. A1 - Kanno, Takayuki A1 - Nose, Naoko A1 - Grunz, Jan-Peter A1 - Onoguchi, Masahisa A1 - Chen, Xinyu A1 - Lapa, Constantin A1 - Buck, Andreas K. A1 - Higuchi, Takahiro T1 - Capabilities of multi-pinhole SPECT with two stationary detectors for in vivo rat imaging JF - Scientific Reports N2 - We aimed to investigate the image quality of the U-SPECT5/CT E-Class a micro single-photon emission computed tomography (SPECT) system with two large stationary detectors for visualization of rat hearts and bones using clinically available \(^{99m}\)Tc-labelled tracers. Sensitivity, spatial resolution, uniformity and contrast-to-noise ratio (CNR) of the small-animal SPECT scanner were investigated in phantom studies using an ultra-high-resolution rat and mouse multi-pinhole collimator (UHR-RM). Point source, hot-rod, and uniform phantoms with \(^{99m}\)Tc-solution were scanned for high-count performance assessment and count levels equal to animal scans, respectively. Reconstruction was performed using the similarity-regulated ordered-subsets expectation maximization (SROSEM) algorithm with Gaussian smoothing. Rats were injected with similar to 100 MBq [\(^{99m}\)TcTc-MIBI or similar to 150 MBq [\(^{99m}\)Tc]Tc-HMDP and received multi-frame micro-SPECT imaging after tracer distribution. Animal scans were reconstructed for three different acquisition times and post-processed with different sized Gaussian filters. Following reconstruction, CNR was calculated and image quality evaluated by three independent readers on a five-point scale from 1="very poor" to 5="very good". Point source sensitivity was 567 cps/MBq and radioactive rods as small as 1.2 mm were resolved with the UHR-RM collimator. Collimator-dependent uniformity was 55.5%. Phantom CNR improved with increasing rod size, filter size and activity concentration. Left ventricle and bone structures were successfully visualized in rat experiments. Image quality was strongly affected by the extent of post-filtering, whereas scan time did not have substantial influence on visual assessment. Good image quality was achieved for resolution range greater than 1.8 mm in bone and 2.8 mm in heart. The recently introduced small animal SPECT system with two stationary detectors and UHR-RM collimator is capable to provide excellent image quality in heart and bone scans in a rat using standardized reconstruction parameters and appropriate post-filtering. However, there are still challenges in achieving maximum system resolution in the sub-millimeter range with in vivo settings under limited injection dose and acquisition time. KW - small animal SPECT KW - HMDP hydroxymethylene diphosphonate KW - skeletal KW - quality KW - scanner Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230616 VL - 10 ER - TY - JOUR A1 - Brammer, Jan C. A1 - Blanke, Gerd A1 - Kellner, Claudia A1 - Hoffmann, Alexander A1 - Herres-Pawlis, Sonja A1 - Schatzschneider, Ulrich T1 - TUCAN: A molecular identifier and descriptor applicable to the whole periodic table from hydrogen to oganesson JF - Journal of Cheminformatics N2 - TUCAN is a canonical serialization format that is independent of domain-specific concepts of structure and bonding. The atomic number is the only chemical feature that is used to derive the TUCAN format. Other than that, the format is solely based on the molecular topology. Validation is reported on a manually curated test set of molecules as well as a library of non-chemical graphs. The serialization procedure generates a canonical “tuple-style” output which is bidirectional, allowing the TUCAN string to serve as both identifier and descriptor. Use of the Python NetworkX graph library facilitated a compact and easily extensible implementation. KW - software library KW - cheminformatics KW - molecular representation KW - chemical identifier KW - canonicalization KW - molecule isomorphism KW - line notations KW - molecular graphs KW - python Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-299730 SN - 1758-2946 VL - 14 IS - 1 ER - TY - JOUR A1 - Fehske, Kai A1 - Berninger, Markus T. A1 - Alm, Lena A1 - Hoffmann, Reinhard A1 - Zellner, Johannes A1 - Kösters, Clemens A1 - Barzen, Stefan A1 - Raschke, Michael J. A1 - Izadpanah, Kaywan A1 - Herbst, Elmar A1 - Domnick, Christoph A1 - Schüttrumpf, Jan Philipp A1 - Krause, Matthias T1 - Aktueller Versorgungsstandard von Patellafrakturen in Deutschland JF - Der Unfallchirurg N2 - Hintergrund Die Versorgung von Patellafrakturen ist technisch anspruchsvoll. Auch wenn die radiologischen Ergebnisse zumeist zufriedenstellend sind, deckt sich dies häufig nicht mit der subjektiven Einschätzung der Patienten. Die klassische Versorgung mittels Drahtzuggurtung weist einige Komplikationen auf. Die winkelstabile Plattenosteosynthese hat sich in den letzten Jahren biomechanisch als vorteilhaft erwiesen. Fragestellung Von wem werden Patellafrakturen in Deutschland versorgt? Wie sieht der aktuelle Versorgungsstandard aus? Haben sich „moderne“ Osteosyntheseformen durchgesetzt? Was sind die häufigsten Komplikationen? Material und Methoden Die Mitglieder der Deutschen Gesellschaft für Orthopädie und Unfallchirurgie sowie der Deutschen Kniegesellschaft wurden aufgefordert, an einer Onlinebefragung teilzunehmen. Ergebnisse Insgesamt wurden 511 komplett ausgefüllte Fragebogen ausgewertet. Die Befragten sind zum größten Teil auf Unfallchirurgie spezialisiert (51,5 %) und verfügen über langjährige Berufserfahrung in Traumazentren. Die Hälfte der Operateure versorgt ≤5 Patellafrakturen jährlich. In knapp 40 % der Fälle wird die präoperative Bildgebung um eine Computertomographie ergänzt. Die klassische Zuggurtung ist noch die bevorzugte Osteosyntheseform bei allen Frakturtypen (Querfraktur 52 %, Mehrfragmentfrakturen 40 %). Bei Mehrfragmentfrakturen entscheiden sich 30 % der Operateure für eine winkelstabile Plattenosteosynthese. Bei Beteiligung des kaudalen Pols dient als zusätzliche Sicherung die McLaughlin-Schlinge (60 %). Diskussion Der Versorgungsstandard von Patellafrakturen in Deutschland entspricht weitgehend der aktualisierten S2e-Leitlinie. Nach wie vor wird die klassische Zuggurtungsosteosynthese als Verfahren der Wahl genutzt. Weitere klinische (Langzeit‑)Studien werden benötigt, um die Vorteile der winkelstabilen Plattenosteosynthese zu verifizieren. N2 - Background The treatment of patella fractures is technically demanding. Although the radiological results are mostly satisfactory, this often does not correspond to the subjective assessment of the patients. The classical treatment with tension band wiring with K‑wires has several complications. Fixed-angle plate osteosynthesis seems to be biomechanically advantageous. Objective Who is treating patella fractures in Germany? What is the current standard of treatment? Have modern forms of osteosynthesis become established? What are the most important complications? Material and methods The members of the German Society for Orthopedics and Trauma Surgery and the German Knee Society were asked to participate in an online survey. Results A total of 511 completed questionnaires were evaluated. Most of the respondents are specialized in trauma surgery (51.5%), have many years of professional experience and work in trauma centers. Of the surgeons 50% treat ≤5 patella fractures annually. In almost 40% of the cases preoperative imaging is supplemented by computed tomography. The classical tension band wiring with K‑wires is still the preferred form of osteosynthesis for all types of fractures (transverse fractures 52%, comminuted fractures 40%). In the case of comminuted fractures 30% of the surgeons choose fixed-angle plate osteosynthesis. If the inferior pole is involved a McLaughlin cerclage is used for additional protection in 60% of the cases. Discussion The standard of care for patella fractures in Germany largely corresponds to the updated S2e guidelines. Tension band wiring is still the treatment of choice. Further (long-term) clinical studies are needed to verify the advantages of fixed-angle plates. T2 - Current treatment standard for patella fractures in Germany KW - Kniegelenk KW - Winkelstabile Platte KW - Klassische Zuggurtung KW - Versorgungsstrategien KW - Umfrage KW - knee joint KW - fixed-angle plate KW - tension band wiring KW - treatment strategy KW - survey Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-235047 SN - 0177-5537 VL - 124 ER - TY - THES A1 - Hoffmann, Jan Vincent T1 - Small-animal SPECT with Two Stationary Detectors: Performance Evaluation and Image Quality Assessment of Multi-pinhole Collimators T1 - Kleintier-SPECT mit Zwei Stationären Detektoren: Leistungsbewertung und Bildqualitätsanalyse von Multipinhole-Kollimatoren N2 - SPECT as a representative of molecular imaging allows visualization of metabolic processes in vivo. In clinical practice, single photon emission imaging is an established modality for myocardial perfusion imaging or the diagnosis of adrenal or neuroendocrine tumors, to name a few. With technical advances in scanner design and data processing leading to improved spatial resolution and image quality, SPECT has become a serious contender in small animal preclinical imaging. With multi-pinhole collimation, submillimeter spatial resolutions are achieved without limiting sensitivity, which has led to a significant increase of interest in SPECT for preclinical research in recent years. In this dissertation, the potential of a two-detector system through an analysis of three dedicated mouse collimators with multi-pinhole configurations was demonstrated. For this, sensitivity, spatial resolution, and uniformity as key parameters were determined. In the second part of the present work, an evaluation of the image quality at different activity concentrations to allow prediction of the system performance related to in vivo studies was performed. Therefore, a visual evaluation, as well as a calculation of the contrastto-noise ratio, was performed using mini Derenzo phantoms for the respective three mouse collimators. To better classify the results, the study was extended by a comparison with the predecessor system. Due to the absence of the third bottom detector, sensitivity and uniformity are slightly compromised. All three collimators were able to achieve a spatial resolution in the submillimeter range, XUHR-M offers a peak resolution of up to 0.35 mm. In terms of resolution, both evaluated systems performed on an equal level. Visual assessment of image quality indicates a slight advantage of the new two-detector system, and the contrast-to-noise ratio seems to benefit from the improved SROSEM algorithm. However, the differences between the two systems are marginal. The U-SPECT5/CT E-Class is proven to be state-of-the-art for small animal imaging and is a powerful instrument for preclinical molecular imaging research. Improvements in system design compensate well for the reduction in the detection area, allowing excellent imaging even with low activity concentrations. N2 - SPECT als Vertreter der molekularen Bildgebung ermöglicht die Visualisierung von Stoffwechselprozessen in vivo. In der klinischen Praxis ist die Einzelphotonen-Emissions-Bildgebung eine etablierte Modalität für die Myokard-Perfusions-Bildgebung oder die Diagnose von Nebennieren- oder neuroendokrinen Tumoren, um nur einige Beispiele zu nennen. Mit den technischen Fortschritten bei der Konstruktion von Scannern und der Datenverarbeitung, die zu einer verbesserten räumlichen Auflösung und Bildqualität führen, ist SPECT zu einem ernstzunehmenden Mitbewerber in der präklinischen Bildgebung von Kleintieren geworden. Unter der Verwendung von Multipinhole-Kollimatoren lassen sich Ortsauflösungen von unter einem Millimeter erzielen, ohne die Sensitivität deutlich einzuschränken. Dies trug dazu bei, dass das Interesse an SPECT in der präklinischen Forschung in den letzten Jahren zugenommen hat. In dieser Dissertation wurde das Potenzial eines Zweidetektorsystems unter Verwendung von drei Multipinhole-Mauskollimatoren evaluiert. Zur Leistungsbewertung wurde Sensitivität, Ortsauflösung und Homogenität bestimmt. Im zweiten Teil dieser Arbeit wurde eine Analyse der Bildqualität mit verschiedenen Aktivitätskonzentrationen durchgeführt, um eine Vorhersage der Leistung des Systems in In-vivo-Studien zu ermöglichen. Dazu wurde eine visuelle Bewertung sowie eine Berechnung des Kontrast-zu-Rausch-Verhältnisses mit Mini-Derenzo-Phantomen für die entsprechenden drei Mauskollimatoren durchgeführt. Um die Ergebnisse besser einordnen zu können, wurde die Studie um einen Vergleich mit dem Vorgängersystem erweitert. Durch das Fehlen des dritten unteren Detektors sind Sensitivität und Homogenität leicht beeinträchtigt. Alle drei Kollimatoren konnten eine Ortsauflösung unter einem Millimeter erreichen, wobei XUHR-M die höchste Auflösung von bis zu 0.35 mm erreicht. Die beiden untersuchten Systeme sind hinsichtlich der Ortsauflösung gleichwertig. Die visuelle Bewertung der Bildqualität deutet auf einen leichten, jedoch nur marginalen Vorteil des neuen Zweidetektorsystems hin, und das Kontrast-zu-Rausch-Verhältnis scheint von dem verbesserten SROSEM-Algorithmus zu profitieren. Das U-SPECT5/CT E-Class ist nachweislich auf dem neuesten Stand der Technik für die Bildgebung bei Kleintieren und ein leistungsfähiges Instrument für die präklinische Forschung. Das System kompensiert die Reduktion der Detektionsfläche und ermöglicht eine hervorragende Bildgebung auch bei geringen Aktivitätskonzentrationen. KW - SPECT KW - small-animal SPECT KW - performance evaluation KW - multi-pinhole collimation Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-328195 ER - TY - JOUR A1 - McFleder, Rhonda L. A1 - Makhotkina, Anastasiia A1 - Groh, Janos A1 - Keber, Ursula A1 - Imdahl, Fabian A1 - Peña Mosca, Josefina A1 - Peteranderl, Alina A1 - Wu, Jingjing A1 - Tabuchi, Sawako A1 - Hoffmann, Jan A1 - Karl, Ann-Kathrin A1 - Pagenstecher, Axel A1 - Vogel, Jörg A1 - Beilhack, Andreas A1 - Koprich, James B. A1 - Brotchie, Jonathan M. A1 - Saliba, Antoine-Emmanuel A1 - Volkmann, Jens A1 - Ip, Chi Wang T1 - Brain-to-gut trafficking of alpha-synuclein by CD11c\(^+\) cells in a mouse model of Parkinson’s disease JF - Nature Communications N2 - Inflammation in the brain and gut is a critical component of several neurological diseases, such as Parkinson’s disease (PD). One trigger of the immune system in PD is aggregation of the pre-synaptic protein, α-synuclein (αSyn). Understanding the mechanism of propagation of αSyn aggregates is essential to developing disease-modifying therapeutics. Using a brain-first mouse model of PD, we demonstrate αSyn trafficking from the brain to the ileum of male mice. Immunohistochemistry revealed that the ileal αSyn aggregations are contained within CD11c+ cells. Using single-cell RNA sequencing, we demonstrate that ileal CD11c\(^+\) cells are microglia-like and the same subtype of cells is activated in the brain and ileum of PD mice. Moreover, by utilizing mice expressing the photo-convertible protein, Dendra2, we show that CD11c\(^+\) cells traffic from the brain to the ileum. Together these data provide a mechanism of αSyn trafficking between the brain and gut. KW - antigen-presenting cells KW - neuroimmunology KW - Parkinson's disease Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357696 VL - 14 ER - TY - JOUR A1 - Harnoš, Jakub A1 - Cañizal, Maria Consuelo Alonso A1 - Jurásek, Miroslav A1 - Kumar, Jitender A1 - Holler, Cornelia A1 - Schambony, Alexandra A1 - Hanáková, Kateřina A1 - Bernatík, Ondřej A1 - Zdráhal, Zbynêk A1 - Gömöryová, Kristína A1 - Gybeľ, Tomáš A1 - Radaszkiewicz, Tomasz Witold A1 - Kravec, Marek A1 - Trantírek, Lukáš A1 - Ryneš, Jan A1 - Dave, Zankruti A1 - Fernández-Llamazares, Ana Iris A1 - Vácha, Robert A1 - Tripsianes, Konstantinos A1 - Hoffmann, Carsten A1 - Bryja, Vítězslav T1 - Dishevelled-3 conformation dynamics analyzed by FRET-based biosensors reveals a key role of casein kinase 1 JF - Nature Communications N2 - Dishevelled (DVL) is the key component of the Wnt signaling pathway. Currently, DVL conformational dynamics under native conditions is unknown. To overcome this limitation, we develop the Fluorescein Arsenical Hairpin Binder- (FlAsH-) based FRET in vivo approach to study DVL conformation in living cells. Using this single-cell FRET approach, we demonstrate that (i) Wnt ligands induce open DVL conformation, (ii) DVL variants that are predominantly open, show more even subcellular localization and more efficient membrane recruitment by Frizzled (FZD) and (iii) Casein kinase 1 ɛ (CK1ɛ) has a key regulatory function in DVL conformational dynamics. In silico modeling and in vitro biophysical methods explain how CK1ɛ-specific phosphorylation events control DVL conformations via modulation of the PDZ domain and its interaction with DVL C-terminus. In summary, our study describes an experimental tool for DVL conformational sampling in living cells and elucidates the essential regulatory role of CK1ɛ in DVL conformational dynamics. KW - biological techniques KW - cell signalling KW - phosphorylation Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227837 VL - 10 ER - TY - JOUR A1 - López, Cristina A1 - Kleinheinz, Kortine A1 - Aukema, Sietse M. A1 - Rohde, Marius A1 - Bernhart, Stephan H. A1 - Hübschmann, Daniel A1 - Wagener, Rabea A1 - Toprak, Umut H. A1 - Raimondi, Francesco A1 - Kreuz, Markus A1 - Waszak, Sebastian M. A1 - Huang, Zhiqin A1 - Sieverling, Lina A1 - Paramasivam, Nagarajan A1 - Seufert, Julian A1 - Sungalee, Stephanie A1 - Russell, Robert B. A1 - Bausinger, Julia A1 - Kretzmer, Helene A1 - Ammerpohl, Ole A1 - Bergmann, Anke K. A1 - Binder, Hans A1 - Borkhardt, Arndt A1 - Brors, Benedikt A1 - Claviez, Alexander A1 - Doose, Gero A1 - Feuerbach, Lars A1 - Haake, Andrea A1 - Hansmann, Martin-Leo A1 - Hoell, Jessica A1 - Hummel, Michael A1 - Korbel, Jan O. A1 - Lawerenz, Chris A1 - Lenze, Dido A1 - Radlwimmer, Bernhard A1 - Richter, Julia A1 - Rosenstiel, Philip A1 - Rosenwald, Andreas A1 - Schilhabel, Markus B. A1 - Stein, Harald A1 - Stilgenbauer, Stephan A1 - Stadler, Peter F. A1 - Szczepanowski, Monika A1 - Weniger, Marc A. A1 - Zapatka, Marc A1 - Eils, Roland A1 - Lichter, Peter A1 - Loeffler, Markus A1 - Möller, Peter A1 - Trümper, Lorenz A1 - Klapper, Wolfram A1 - Hoffmann, Steve A1 - Küppers, Ralf A1 - Burkhardt, Birgit A1 - Schlesner, Matthias A1 - Siebert, Reiner T1 - Genomic and transcriptomic changes complement each other in the pathogenesis of sporadic Burkitt lymphoma JF - Nature Communications N2 - Burkitt lymphoma (BL) is the most common B-cell lymphoma in children. Within the International Cancer Genome Consortium (ICGC), we performed whole genome and transcriptome sequencing of 39 sporadic BL. Here, we unravel interaction of structural, mutational, and transcriptional changes, which contribute to MYC oncogene dysregulation together with the pathognomonic IG-MYC translocation. Moreover, by mapping IGH translocation breakpoints, we provide evidence that the precursor of at least a subset of BL is a B-cell poised to express IGHA. We describe the landscape of mutations, structural variants, and mutational processes, and identified a series of driver genes in the pathogenesis of BL, which can be targeted by various mechanisms, including IG-non MYC translocations, germline and somatic mutations, fusion transcripts, and alternative splicing. KW - cancer genomics KW - lymphocytes KW - lymphoid tissues KW - oncology Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-237281 VL - 10 ER -