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Ebel S, Kühn A, Köhler B, Behrendt B, Riekena B, Preim B, Denecke T, Grothoff M, Gutberlet M. Quantitative 4D flow MRI-derived thoracic aortic normal values of 2D flow MRI parameters in healthy volunteers. ROFO-FORTSCHR RONTG 2024; 196:273-282. [PMID: 37944940 DOI: 10.1055/a-2175-4165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
PURPOSE To utilize 4 D flow MRI to acquire normal values of "conventional 2 D flow MRI parameters" in healthy volunteers in order to replace multiple single 2 D flow measurements with a single 4 D flow acquisition. MATERIALS AND METHODS A kt-GRAPPA accelerated 4 D flow sequence was used. Flow volumes were assessed by forward (FFV), backward (BFV), and net flow volumes (NFV) [ml/heartbeat] and flow velocities by axial (VAX) and absolute velocity (VABS) [m/s] in 116 volunteers (58 females, 43 ± 13 years). The aortic regurgitant fraction (RF) was calculated. RESULTS The sex-neutral mean FFV, BFV, NFV, and RF in the ascending aorta were 93.5 ± 14.8, 3.6 ± 2.8, 89.9 ± 0.6 ml/heartbeat, and 3.9 ± 2.9 %, respectively. Significantly higher values were seen in males regarding FFV, BFV, NFV and RF, but there was no sex dependency regarding VAX and VABS. The mean maximum VAX was lower (1.01 ± 0.31 m/s) than VABS (1.23 ± 0.35 m/s). We were able to determine normal ranges for all intended parameters. CONCLUSION This study provides quantitative 4 D flow-derived thoracic aortic normal values of 2 D flow parameters in healthy volunteers. FFV, BFV, NFV, and VAX did not differ significantly from single 2 D flow acquisitions and could therefore replace time-consuming multiple single 2 D flow acquisitions. VABS should not be used interchangeably. KEY POINTS · 4 D flow MRI can be used to replace 2 D flow MRI measurements.. · The parameter absolute velocities can be assessed by 4 D flow MRI.. · There are sex-dependent differences regarding forward, backward, net aortic blood flow and the aortic valve regurgitant fraction..
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Affiliation(s)
- Sebastian Ebel
- Diagnostic and Interventional Radiology, Leipzig University, Leipzig, Germany
| | - Alexander Kühn
- Diagnostic and Interventional Radiology, Leipzig Heart Centre University Hospital, Leipzig, Germany
| | - Benjamin Köhler
- Simulation and Graphics, Otto von Guericke Universität Magdeburg, Germany
| | - Benjamin Behrendt
- Simulation and Graphics, Otto von Guericke Universität Magdeburg, Germany
| | - Boris Riekena
- Diagnostic and Interventional Radiology, Leipzig Heart Centre University Hospital, Leipzig, Germany
| | - Bernhard Preim
- Simulation and Graphics, Otto von Guericke Universität Magdeburg, Germany
| | - Timm Denecke
- Diagnostic and Interventional Radiology, Leipzig University, Leipzig, Germany
| | - Matthias Grothoff
- Diagnostic and Interventional Radiology, Leipzig Heart Centre University Hospital, Leipzig, Germany
| | - Matthias Gutberlet
- Diagnostic and Interventional Radiology, Leipzig Heart Centre University Hospital, Leipzig, Germany
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Ebel S, Köhler B, Aggarwal A, Preim B, Behrendt B, Jung B, Gohmann RF, Riekena B, Borger M, Lurz P, Denecke T, Grothoff M, Gutberlet M. Comparison of aortic blood flow rotational direction in healthy volunteers and patients with bicuspid aortic valves using volumetric velocity-sensitive cardiovascular magnetic resonance imaging. Quant Imaging Med Surg 2023; 13:7973-7986. [PMID: 38106267 PMCID: PMC10722022 DOI: 10.21037/qims-23-183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 09/13/2023] [Indexed: 12/19/2023]
Abstract
Background The rotational direction (RD) of helical blood flow can be classified as either a clockwise (RD+) or counter-clockwise (RD-) flow. We hypothesized that this simple classification might not be sufficient for analysis in vivo and a simultaneous existence of RD+/- may occur. We utilized volumetric velocity-sensitive cardiovascular magnetic resonance imaging (4D flow MRI) to analyze rotational blood flow in the thoracic aorta. Methods Forty volunteers (22 females; mean age, 41±16 years) and seventeen patients with bicuspid aortic valves (BAVs) (9 females; mean age, 42±14 years) were prospectively included. The RDs and the calculation of the rotating blood volumes (RBVs) in the thoracic aorta were performed using a pathline-projection strategy. Results We could confirm a mainly clockwise RD in the ascending, descending aorta and in the aortic arch. Furthermore, we found a simultaneous existence of RD+/RD-. The RD+/--volume in the ascending aorta was significantly higher in BAV patients, the mean RD+/RD- percentage was approximately 80%/20% vs. 60%/40% in volunteers (P<0.01). The maximum RBV always occurred during systole. There was significantly more clockwise than counter-clockwise rotational flow in the ascending aorta (P<0.01) and the aortic arch (P<0.01), but no significant differences in the descending aorta (P=0.48). Conclusions A simultaneous occurrence of RD+/RD- indicates that a simple categorization in either of both is insufficient to describe blood flow in vivo. Rotational flow in the ascending aorta and in the aortic arch differs significantly from flow in the descending aorta. BAV patients show significantly more clockwise rotating volume in the ascending aorta compared to healthy volunteers.
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Affiliation(s)
- Sebastian Ebel
- Department of Diagnostic and Interventional Radiology, University of Leipzig – Heart Centre, Leipzig, Germany
- Department of Diagnostic and Interventional Radiology, University of Leipzig, Leipzig, Germany
| | - Benjamin Köhler
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | | | - Bernhard Preim
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Benjamin Behrendt
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Bernd Jung
- Department of Diagnostic, Interventional and Paediatric Radiology, University of Bern, Bern, Switzerland
| | - Robin F. Gohmann
- Department of Diagnostic and Interventional Radiology, University of Leipzig – Heart Centre, Leipzig, Germany
| | - Boris Riekena
- Department of Diagnostic and Interventional Radiology, University of Leipzig – Heart Centre, Leipzig, Germany
| | - Michael Borger
- Department of Cardiac Surgery, University Leipzig – Heart Centre, Leipzig, Germany
| | - Philipp Lurz
- Department of Cardiology, University Leipzig – Heart Centre, Leipzig, Germany
| | - Timm Denecke
- Department of Diagnostic and Interventional Radiology, University of Leipzig, Leipzig, Germany
| | - Matthias Grothoff
- Department of Diagnostic and Interventional Radiology, University of Leipzig – Heart Centre, Leipzig, Germany
| | - Matthias Gutberlet
- Department of Diagnostic and Interventional Radiology, University of Leipzig – Heart Centre, Leipzig, Germany
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Sobol B, Hoffmeister P, Scherr AL, Kessler A, Nader L, Schmitt N, Jäger D, Welte S, Seidensaal K, Christopoulos P, Kriegsmann K, Fröhling S, Kriegsmann M, Köhler B. 8P Targeting antiapoptotic Bcl-2 proteins with highly specific BH3 mimetics in solid tumors. ESMO Open 2023. [DOI: 10.1016/j.esmoop.2023.100974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023] Open
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Ebel S, Kühn A, Aggarwal A, Köhler B, Behrendt B, Gohmann R, Riekena B, Lücke C, Ziegert J, Vogtmann C, Preim B, Kropf S, Jung B, Denecke T, Grothoff M, Gutberlet M. Quantitative normal values of helical flow, flow jets and wall shear stress of healthy volunteers in the ascending aorta. Eur Radiol 2022; 32:8597-8607. [PMID: 35612663 DOI: 10.1007/s00330-022-08866-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 04/08/2022] [Accepted: 05/08/2022] [Indexed: 11/26/2022]
Abstract
OBJECTIVES 4D flow MRI enables quantitative assessment of helical flow. We sought to generate normal values and elucidate changes of helical flow (duration, volume, length, velocities and rotational direction) and flow jet (displacement, flow angle) as well as wall shear stress (WSS). METHODS We assessed the temporal helical existence (THEX), maximum helical volume (HVmax), accumulated helical volume (HVacc), accumulated helical volume length (HVLacc), maximum forward velocity (maxVfor), maximum circumferential velocity (maxVcirc), rotational direction (RD) and maximum wall shear stress (WSS) as reported elsewhere using the software tool Bloodline in 86 healthy volunteers (46 females, mean age 41 ± 13 years). RESULTS WSS decreased by 42.1% and maxVfor by 55.7% across age. There was no link between age and gender regarding the other parameters. CONCLUSION This study provides age-dependent normal values regarding WSS and maxVfor and age- and gender-independent normal values regarding THEX, HVmax, HVacc, HVLacc, RD and maxVcirc. KEY POINTS • 4D flow provides numerous new parameters; therefore, normal values are mandatory. • Wall shear stress decreases over age. • Maximum helical forward velocity decreases over age.
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Affiliation(s)
- Sebastian Ebel
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany.
- Department of Diagnostic and Interventional Radiology, University of Leipzig, Liebigstr. 20, 04103, Leipzig, Germany.
| | - Alexander Kühn
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Abhinav Aggarwal
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
- Department of Radiology, Mata Chanan Devi Hospital of New Delhi, New Delhi, India
| | - Benjamin Köhler
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Benjamin Behrendt
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Robin Gohmann
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Boris Riekena
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Christian Lücke
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Juliane Ziegert
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Charlotte Vogtmann
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Bernhard Preim
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Siegfried Kropf
- Department for Biometry and Medical Informatics, University of Magdeburg, Magdeburg, Germany
| | - Bernd Jung
- Department of Diagnostic, Interventional and Paediatric Radiology, University of Bern, Bern, Switzerland
| | - Timm Denecke
- Department of Diagnostic and Interventional Radiology, University of Leipzig, Liebigstr. 20, 04103, Leipzig, Germany
| | - Matthias Grothoff
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Matthias Gutberlet
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
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Köhm M, Ohrndorf S, Rossmanith T, Backhaus M, Burmester GR, Wassenberg S, Köhler B, Burkhardt H, Behrens F. AB1111 PREDICTIVE VALUE OF FLUORESCENCE-OPTICAL IMAGING TECHNIQUE IN DETECTION OF PSORIATIC ARTHRITIS IN PSORIASIS PATIENTS. Ann Rheum Dis 2020. [DOI: 10.1136/annrheumdis-2020-eular.5300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background:Psoriasis (Pso) is one of the most common chronic inflammatory skin diseases in Europe. Psoriatic arthritis (PsA) is closely associated to Pso whereas the skin manifestation appears usually years before PsA-related symptoms emerge. Up to 30% of Pso patients develop PsA, but there is no clear correlation between disease duration of Pso and PsA development. Therefore, biomarkers for its early detection are of major importance. In early PsA, changes in synovial vascularisation combined with increased expression of proangiogenic factors appear first. Therefore, imaging biomarkers for detection of changes in vascularisation might be useful for early detection of musculoskeletal disease. Fluorescence-optical imaging (FOI) is a new method to detect changes in microvascularisation of the hands.Objectives:To determine the number of positive PsA diagnosis within a 24 month follow-up period in PsO only patients with subclinical MSK-inflammation detected in FOI.Methods:Sensitivity of FOI for detection of subclinical signs of musculoskeletal inflammation as biomarker for early PsA was observed in a prospective, multicentre study (XCITING) including patients with dermatological confirmed skin psoriasis. 411 patients were included from dermatology care units across Germany without diagnosis of PsA but potential risk factors for its development (nail psoriasis and/or joint pain or swelling within the last 6 months). Clinical examination (CE; swollen (66) and tender (68) joint count, enthesitis, dactylitis assessment) and standardised ultrasound (US) assessment was performed by a qualified rheumatologist to assess musculoskeletal inflammation. FOI was performed additionally. Data was analysed in focus on increased vascularisation of musculoskeletal structures as inflammatory markers. In case of discrepant results (positive FOI and negative CE and US), MRI was performed to prove the findings. In case of MRI negativity, a follow-up period of 24-months was performed including FOI, CE, US and MRI assessment.Results:83 of the 411 patients of the cohort were negative in all assessments (Pso only), 136 of the 411 patients were classified as PsA by rheumatologic assessments. 119 patients showed subclinical signs of musculoskeletal inflammation in the central reading of FOI, whereas CE and US were negative. In 37,5% of those patients, subclinical inflammation was confirmed by MRI assessment. 22 patients of the cohort without MRI positivity were willing to be followed up until month 24. 5 (7.5%) patients developed a clinical PsA until month 24 whereas 7 (10.5%) patients converted to be FOI negative. In 5 patients an additional MRI examination was performed in which one patient showed positive signs for inflammation.Conclusion:FOI is an innovative method for measurement of changes in microvascularisation in the hands. 6/22 patients initial only positive in FOI (no clinical signs for PsA, negative US, negative MRI) developed either clinical evident PsA (n=5) or new inflammation in MRI (n=1) during follow-up of 24 months. Therefore, FOI positive signals in PsO patients increase the probability for PsA development.Figure 1.Flow Chart of the Follow-up period of the XCITING study.Disclosure of Interests:Michaela Köhm Grant/research support from: Pfizer, Janssen, BMS, LEO, Consultant of: BMS, Pfizer, Speakers bureau: Pfizer, BMS, Janssen, Novartis, Sarah Ohrndorf: None declared, Tanja Rossmanith Grant/research support from: Janssen, BMS, LEO, Pfizer, Marina Backhaus Grant/research support from: Pfizer, Gerd Rüdiger Burmester Consultant of: AbbVie Inc, Eli Lilly, Gilead, Janssen, Merck, Roche, Pfizer, and UCB Pharma, Speakers bureau: AbbVie Inc, Eli Lilly, Gilead, Janssen, Merck, Roche, Pfizer, and UCB Pharma, Siegfried Wassenberg: None declared, Benjamin Köhler Grant/research support from: Pfizer, Harald Burkhardt Grant/research support from: Pfizer, Roche, Abbvie, Consultant of: Sanofi, Pfizer, Roche, Abbvie, Boehringer Ingelheim, UCB, Eli Lilly, Chugai, Bristol Myer Scripps, Janssen, and Novartis, Speakers bureau: Sanofi, Pfizer, Roche, Abbvie, Boehringer Ingelheim, UCB, Eli Lilly, Chugai, Bristol Myer Scripps, Janssen, and Novartis, Frank Behrens Grant/research support from: Pfizer, Janssen, Chugai, Celgene, Lilly and Roche, Consultant of: Pfizer, AbbVie, Sanofi, Lilly, Novartis, Genzyme, Boehringer, Janssen, MSD, Celgene, Roche and Chugai
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Ebel S, Dufke J, Köhler B, Preim B, Behrendt B, Riekena B, Jung B, Stehning C, Kropf S, Grothoff M, Gutberlet M. Automated Quantitative Extraction and Analysis of 4D flow Patterns in the Ascending Aorta: An intraindividual comparison at 1.5 T and 3 T. Sci Rep 2020; 10:2949. [PMID: 32076060 PMCID: PMC7031260 DOI: 10.1038/s41598-020-59826-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 01/29/2020] [Indexed: 12/28/2022] Open
Abstract
4D flow MRI enables quantitative assessment of helical flow. Current methods are susceptible to noise. To evaluate helical flow patterns in healthy volunteers and patients with bicuspid aortic valves (BAV) at 1.5 T and 3 T using pressure-based helix-extraction in 4D flow MRI. Two intraindividual 4D flow MRI examinations were performed at 1.5 T and 3 T in ten healthy volunteers (5 females, 32 ± 3 years) and 2 patients with BAV using different acceleration techniques (kt-GRAPPA and centra). Several new quantitative parameters for the evaluation of volumes [ml], lengths [mm] as well as temporal parameters [ms] of helical flow were introduced and analyzed using the software tool Bloodline. We found good correlations between measurements in volunteers at 1.5 T and 3 T regarding helical flow volumes (R = 0.98) and temporal existence (R = 0.99) of helices in the ascending aorta. Furthermore, we found significantly larger (11.7 vs. 77.6 ml) and longer lasting (317 vs. 769 ms) helices in patients with BAV than in volunteers. The assessed parameters do not depend on the magnetic field strength used for the acquisition. The technique of pressure-based extraction of 4D flow MRI pattern is suitable for differentiation of normal and pathological flow.
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Affiliation(s)
- Sebastian Ebel
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany. .,Department of Diagnostic and Interventional Radiology, University of Leipzig, Leipzig, Germany.
| | - Josefin Dufke
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Benjamin Köhler
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Bernhard Preim
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Benjamin Behrendt
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Boris Riekena
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Bernd Jung
- Department of Diagnostic, Interventional and paediatric Radiology, University of Bern, Bern, Switzerland
| | | | - Siegfried Kropf
- Institute for Biometrics and Medical Informatics, University of Magdeburg, Magdeburg, Germany
| | - Matthias Grothoff
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
| | - Matthias Gutberlet
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany
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Krege S, Eckoldt F, Richter-Unruh A, Köhler B, Leuschner I, Mentzel HJ, Moss A, Schweizer K, Stein R, Werner-Rosen K, Wieacker P, Wiesemann C, Wünsch L, Richter-Appelt H. Variations of sex development: The first German interdisciplinary consensus paper. J Pediatr Urol 2019; 15:114-123. [PMID: 30713084 DOI: 10.1016/j.jpurol.2018.10.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/10/2018] [Indexed: 11/24/2022]
Abstract
INTRODUCTION The term variations of sex development subsumes a large number of congenital conditions including chromosomal mosaics and variations of chromosomal, gonadal, and phenotypic sex. A situation of this nature may cause severe distress to both, parents and affected persons. One of the reasons for this is the binary form of gender classification in the society. In the past, because of a fear of possible stigmatization and an inability to cope with complex situations, it has been medical policy and practice for newborns to undergo early, mostly 'feminizing' elective surgery with the aim of achieving an outer genital appearance that is unambiguously male or female. Protests by advocacy groups for the most part as well as the results of outcome studies have shown that the development of affected persons may be very different to what has been expected and often does not result in the intended clear female or male gender identity as had been intended. It, therefore, seemed a matter of urgency to implement this new awareness as well as the ethical and personal human rights perspectives in the recommendations for the medical and psychosocial management of diverse sex development (DSD) in the future. STUDY DESIGN In 2012, an interdisciplinary group of German academics engaged in the field of DSD decided to work on a consensus paper for this topic. It involved the participation of all faculties and non-scientific groups dealing with DSD, in particular advocacy and service-user groups. In a structured consensus, process recommendations were developed based on scientific literature as well as personal experiences of clinicians and affected individuals. RESULTS Finally, 37 recommendations were agreed on. The strength of consensus is reflected in the degree of agreement as expressed in percentages. CONCLUSION The introduction of the consensus paper reflects on the emerging paradigm shift and the necessity for a more open view of gender within society. The paper is intended to aid the performance of appropriate diagnostics in DSD-affected newborns and especially to help parents and affected persons cope with the biological and social consequences of DSD. With regard to medical or surgical therapy, it gives information about the most recent treatment trends.
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Affiliation(s)
- S Krege
- Dept. of Urology, Kliniken Essen-Mitte, Germany.
| | - F Eckoldt
- Dept. of Pediatric Surgery, University of Jena, Germany
| | - A Richter-Unruh
- Dept. of Pediatric Endocrinology, University of Münster, Germany
| | - B Köhler
- Dept. of Pediatric Endocrinology and Diabetology, Charite - University of Berlin, Germany
| | - I Leuschner
- Dept. of Pathology, University of Kiel, Germany
| | - H-J Mentzel
- Section of Pediatric Radiology, University of Jena, Germany
| | - A Moss
- Division of Pediatric Endocrinology and Diabetes, Dept. of Pediatrics and Adolescent Medicine, University of Ulm, Germany
| | - K Schweizer
- Institute for Sex Research and Forensic Psychiatry, University Medical Center, Hamburg-Eppendorf, Germany
| | - R Stein
- Department of Pediatric, Adolescent and reconstructive Urology, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | | | - P Wieacker
- Institute of Human Genetics, University of Münster, Germany
| | - C Wiesemann
- Institute of Medical Ethics and History of Medicine, University of Göttingen, Germany
| | - L Wünsch
- Dept. of Pediatric Surgery, University of Lübeck, Germany
| | - H Richter-Appelt
- Institute for Sex Research and Forensic Psychiatry, University Medical Center, Hamburg-Eppendorf, Germany
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Ebel S, Hübner L, Köhler B, Kropf S, Preim B, Jung B, Grothoff M, Gutberlet M. Validation of two accelerated 4D flow MRI sequences at 3 T: a phantom study. Eur Radiol Exp 2019; 3:10. [PMID: 30806827 PMCID: PMC6391502 DOI: 10.1186/s41747-019-0089-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 02/01/2019] [Indexed: 12/15/2022] Open
Abstract
Background Four-dimensional (4D) flow magnetic resonance imaging (MRI) sequences with advanced parallel imaging have the potential to reduce scan time with equivalent image quality and accuracy compared with standard two-dimensional (2D) flow MRI. We compared 4D flow to standard 2D flow sequences using a constant and pulsatile flow phantom at 3 T. Methods Two accelerated 4D flow sequences (GRAPPA2 and k-t-GRAPPA5) were evaluated regarding the concordance of flow volumes, flow velocities, and reproducibility as well as dependency on measuring plane and velocity encoding (Venc). The calculated flow volumes and peak velocities of the phantom were used as reference standard. Flow analysis was performed using the custom-made software “Bloodline”. Results No significant differences in flow volume were found between the 2D, both 4D flow MRI sequences, and the pump reference (p = 0.994) or flow velocities (p = 0.998) in continuous and pulsatile flow. An excellent correlation (R = 0.99–1.0) with a reference standard and excellent reproducibility of measurements (R = 0.99) was achieved for all sequences. A Venc overestimated by up to two times had no impact on flow measurements. However, misaligned measuring planes led to an increasing underestimation of flow volume and mean velocity in 2D flow accuracy, while both 4D flow measurements were not affected. Scan time was significantly shorter for k-t-GRAPPA5 (1:54 ± 0:01 min, mean ± standard deviation) compared to GRAPPA2 (3:56 ± 0:02 min) (p = 0.002). Conclusions Both 4D flow sequences demonstrated equal agreement with 2D flow measurements, without impact of Venc overestimation and plane misalignment. The highly accelerated k-t-GRAPPA5 sequence yielded results similar to those of GRAPPA2.
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Affiliation(s)
- Sebastian Ebel
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig Strümpellstrasse 39, 04289, Leipzig, Germany.
| | - Lisa Hübner
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig Strümpellstrasse 39, 04289, Leipzig, Germany
| | - Benjamin Köhler
- Department of Simulations and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Siegfried Kropf
- Institute for Biometrics and Medical Informatics, University of Magdeburg, Magdeburg, Germany
| | - Bernhard Preim
- Department of Simulations and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Bernd Jung
- Department of Diagnostic, Interventional and Paediatric Radiology, University of Bern, Bern, Switzerland
| | - Matthias Grothoff
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig Strümpellstrasse 39, 04289, Leipzig, Germany
| | - Matthias Gutberlet
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig Strümpellstrasse 39, 04289, Leipzig, Germany
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Voigt M, Schmidt S, Lehmann T, Köhler B, Kloos C, Voigt UA, Meller D, Wolf G, Müller UA, Müller N. Correction: Prevalence and Progression Rate of Diabetic Retinopathy in Type 2 Diabetes Patients in Correlation with the Duration of Diabetes. Exp Clin Endocrinol Diabetes 2018; 126:e2. [PMID: 30332687 DOI: 10.1055/a-0757-3796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Margarete Voigt
- Department of Internal Medicine III, University Hospital Jena, Jena, Germany
| | - Sebastian Schmidt
- Department of Internal Medicine III, University Hospital Jena, Jena, Germany
| | - Thomas Lehmann
- Department of Medical Statistics, University Hospital Jena, Information and Documentation, Jena, Germany
| | - Benjamin Köhler
- Department of Internal Medicine III, University Hospital Jena, Jena, Germany
| | - Christof Kloos
- Department of Internal Medicine III, University Hospital Jena, Jena, Germany
| | - Ulrich A Voigt
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
| | - Daniel Meller
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
| | - Gunter Wolf
- Department of Internal Medicine III, University Hospital Jena, Jena, Germany
| | - Ulrich A Müller
- Department of Internal Medicine III, University Hospital Jena, Jena, Germany
| | - Nicolle Müller
- Department of Internal Medicine III, University Hospital Jena, Jena, Germany
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Köhler B, Allgeier S, Bartschat A, Guthoff RF, Bohn S, Reichert KM, Stachs O, Winter K, Mikut R. [In vivo imaging of the corneal nerve plexus : From single image to large scale map]. Ophthalmologe 2018; 114:601-607. [PMID: 28283769 DOI: 10.1007/s00347-017-0464-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The sub-basal nerve plexus (SNP) of the cornea provides the possibility of in vivo and non-invasive examination of peripheral nerve structures by corneal confocal microscopy (CCM). Thus morphological alterations of the SNP can be directly detected and quantified. A single CCM image is insufficient for a well-founded diagnosis because of the inhomogeneous distribution of the nerve fibers; therefore, there is a demand for techniques for large area imaging of the SNP. This article provides an overview of published approaches to the problem. Current developmental work at the Karlsruhe Institute of Technology and the University of Rostock Eye Clinic is expected to lead to a simplified handling of the technology and a further improvement in the image quality.
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Affiliation(s)
- B Köhler
- Institut für Angewandte Informatik, Karlsruher Institut für Technologie, Kaiserstraße 12, 76131, Karlsruhe, Deutschland.
| | - S Allgeier
- Institut für Angewandte Informatik, Karlsruher Institut für Technologie, Kaiserstraße 12, 76131, Karlsruhe, Deutschland
| | - A Bartschat
- Institut für Angewandte Informatik, Karlsruher Institut für Technologie, Kaiserstraße 12, 76131, Karlsruhe, Deutschland
| | - R F Guthoff
- Universitätsaugenklinik, Universitätsmedizin Rostock, Rostock, Deutschland
| | - S Bohn
- Universitätsaugenklinik, Universitätsmedizin Rostock, Rostock, Deutschland
| | - K-M Reichert
- Institut für Angewandte Informatik, Karlsruher Institut für Technologie, Kaiserstraße 12, 76131, Karlsruhe, Deutschland
| | - O Stachs
- Universitätsaugenklinik, Universitätsmedizin Rostock, Rostock, Deutschland
| | - K Winter
- Institut für Anatomie, Medizinische Fakultät, Universität Leipzig, Leipzig, Deutschland
| | - R Mikut
- Institut für Angewandte Informatik, Karlsruher Institut für Technologie, Kaiserstraße 12, 76131, Karlsruhe, Deutschland
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Köhler B, Kißler H, Bärthel E, Raack S, Müller UA, Kloos C. Psychische Belastung schwächt den Erfolg im konservativen Abnehmversuch stark adipöser Menschen. DIABETOL STOFFWECHS 2018. [DOI: 10.1055/s-0038-1641834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- B Köhler
- Universitätsklinikum Jena – Klinik für Innere Medizin III, FB Endokrinologie & Stoffwechselkrankheiten, Jena, Germany
| | - H Kißler
- Universitätsklinikum Jena, Klinik für Allgemein- und Viszeralchirurgie, Jena, Germany
| | - E Bärthel
- Universitätsklinikum Jena, Klinik für Allgemein- und Viszeralchirurgie, Jena, Germany
| | - S Raack
- Universitätsklinikum Jena, Institut für Psychosoziale Medizin und Psychotherapie, Jena, Germany
| | - UA Müller
- Universitätsklinikum Jena – Klinik für Innere Medizin III, FB Endokrinologie & Stoffwechselkrankheiten, Jena, Germany
| | - C Kloos
- Universitätsklinikum Jena – Klinik für Innere Medizin III, FB Endokrinologie & Stoffwechselkrankheiten, Jena, Germany
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Engels M, Gehrmann K, Falhammar H, Webb EA, Nordenström A, Sweep FC, Span PN, van Herwaarden AE, Rohayem J, Richter-Unruh A, Bouvattier C, Köhler B, Kortmann BB, Arlt W, Roeleveld N, Reisch N, Stikkelbroeck NMML, Claahsen-van der Grinten HL. Gonadal function in adult male patients with congenital adrenal hyperplasia. Eur J Endocrinol 2018; 178:285-294. [PMID: 29339528 DOI: 10.1530/eje-17-0862] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 01/15/2018] [Indexed: 11/08/2022]
Abstract
CONTEXT Current knowledge on gonadal function in congenital adrenal hyperplasia (CAH) is mostly limited to single-center/country studies enrolling small patient numbers. Overall data indicate that gonadal function can be compromised in men with CAH. OBJECTIVE To determine gonadal function in men with CAH within the European 'dsd-LIFE' cohort. DESIGN Cross-sectional clinical outcome study, including retrospective data from medical records. METHODS Fourteen academic hospitals included 121 men with CAH aged 16-68 years. Main outcome measures were serum hormone concentrations, semen parameters and imaging data of the testes. RESULTS At the time of assessment, 14/69 patients had a serum testosterone concentration below the reference range; 7 of those were hypogonadotropic, 6 normogonadotropic and 1 hypergonadotropic. In contrast, among the patients with normal serum testosterone (55/69), 4 were hypogonadotropic, 44 normogonadotropic and 7 hypergonadotropic. The association of decreased testosterone with reduced gonadotropin concentrations (odds ratio (OR) = 12.8 (2.9-57.3)) was weaker than the association between serum androstenedione/testosterone ratio ≥1 and reduced gonadotropin concentrations (OR = 39.3 (2.1-732.4)). Evaluation of sperm quality revealed decreased sperm concentrations (15/39), motility (13/37) and abnormal morphology (4/28). Testicular adrenal rest tumor (TART)s were present in 39/80 patients, with a higher prevalence in patients with the most severe genotype (14/18) and in patients with increased current 17-hydroxyprogesterone 20/35) or androstenedione (12/18) serum concentrations. Forty-three children were fathered by 26/113 patients. CONCLUSIONS Men with CAH have a high risk of developing hypothalamic-pituitary-gonadal disturbances and spermatogenic abnormalities. Regular assessment of endocrine gonadal function and imaging for TART development are recommended, in addition to measures for fertility protection.
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Affiliation(s)
- M Engels
- Department of Pediatrics, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, the Netherlands
- Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University Medical Center, Nijmegen, the Netherlands
| | - K Gehrmann
- Klinik für Pädiatrie m.S. Endokrinologie und Diabetologie, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - H Falhammar
- Department of Endocrinology, Metabolism and Diabetes, Karolinska University Hospital, Stockholm, Sweden
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
| | - E A Webb
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - A Nordenström
- Department of Women's and Children's Health, Division of Pediatric Endocrinology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - F C Sweep
- Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University Medical Center, Nijmegen, the Netherlands
| | - P N Span
- Department of Radiation Oncology, Radiotherapy & OncoImmunology laboratory, RIMLS, Radboud University Medical Center, Nijmegen, the Netherlands
| | - A E van Herwaarden
- Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University Medical Center, Nijmegen, the Netherlands
| | - J Rohayem
- Centre of Reproductive Medicine and Andrology, Clinical Andrology, University Hospital Münster, Münster, Germany
| | - A Richter-Unruh
- Centre of Reproductive Medicine and Andrology, Clinical Andrology, University Hospital Münster, Münster, Germany
| | - C Bouvattier
- Endocrinologie Pédiatrique, Centre de Référence des Maladies Rares du Développement Sexuel, Hôpital Bicêtre, Université Paris-Sud, Le Kremlin-Bicêtre, France
| | - B Köhler
- Klinik für Pädiatrie m.S. Endokrinologie und Diabetologie, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - B B Kortmann
- Department of Pediatric Urology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - W Arlt
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - N Roeleveld
- Department for Health Evidence, Radboud University Medical Center, Nijmegen, the Netherlands
| | - N Reisch
- Medizinische Klinik IV, Klinikum der Universität München, München, Germany
| | - N M M L Stikkelbroeck
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - H L Claahsen-van der Grinten
- Department of Pediatrics, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, the Netherlands
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Sereno MF, Köhler B, Preim B. Comparison of Divergence-Free Filters for Cardiac 4D PC-MRI Data. Bildverarbeitung für die Medizin 2018 2018. [DOI: 10.1007/978-3-662-56537-7_44] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Voigt M, Schmidt S, Lehmann T, Köhler B, Kloos C, Voigt UA, Meller D, Wolf G, Müller UA, Müller N. Prevalence and Progression Rate of Diabetic Retinopathy in Type 2 Diabetes Patients in Correlation with the Duration of Diabetes. Exp Clin Endocrinol Diabetes 2017; 126:570-576. [PMID: 29183104 DOI: 10.1055/s-0043-120570] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
AIMS We examined prevalence and progression of retinopathy in dependence on diabetes duration in order to estimate the probability of progression. PATIENTS/METHODS In a retrospective cohort-analysis from an academic outpatient department of endocrinology and metabolic diseases we analyzed 17461 consultations of 4513 patients with DM2 from 1987 to 2014. 50.3% of the patients (n=2272) had at least one documented result of funduscopy. RESULTS 25.8% of the patients had retinopathy (20.2% non-proliferative, 4.7% proliferative, 0.7% were not classified, 0.1% blindness). The prevalence of retinopathy in dependence on diabetes duration was 1.1% at diagnosis, 6.6% after 0<5 years, 12% after 5<10 years, 24% after 10<15 years, 39.9% after 15<20 years, 52.7% after 20<25 years, 58.7% after 25<30 years and 63% after ≥30 years. In a subset of 586 (25.7%) patients with retinal photography of 3 consecutive years 7.0% showed deterioration after one and 12.2% after two years; 2.6% improved after one and 2.8% after two years. 201 (34.3%) of this group had<10 years diabetes and lower deterioration (4.5% worsened after one and 9.5% after two years). Their retinopathy mainly transformed from no retinopathy to non-proliferative. Four patients (2.0%) developed proliferative retinopathy. CONCLUSIONS/INTERPRETATIONS Within the first 10 years of diabetes duration, the prevalence of retinopathy is low and the progression infrequent. Most patients have a non-proliferative form which can be reversible and rarely requires interventions. Patients with DM2 without retinopathy and good glycaemic control do not run into additional risk from expanding funduscopy intervals to biennial.
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Affiliation(s)
- Margarete Voigt
- Department of Internal Medicine III, University Hospital Jena, Jena, Germany
| | - Sebastian Schmidt
- Department of Internal Medicine III, University Hospital Jena, Jena, Germany
| | - Thomas Lehmann
- Department of Medical Statistics, University Hospital Jena, Information and Documentation, Jena, Germany
| | - Benjamin Köhler
- Department of Internal Medicine III, University Hospital Jena, Jena, Germany
| | - Christof Kloos
- Department of Internal Medicine III, University Hospital Jena, Jena, Germany
| | - Ulrich A Voigt
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
| | - Daniel Meller
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
| | - Gunter Wolf
- Department of Internal Medicine III, University Hospital Jena, Jena, Germany
| | - Ulrich A Müller
- Department of Internal Medicine III, University Hospital Jena, Jena, Germany
| | - Nicolle Müller
- Department of Internal Medicine III, University Hospital Jena, Jena, Germany
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Allgeier S, Reichert K, Stachs O, Köhler B. Mosaicking the subbasal nerve plexus. Acta Ophthalmol 2017. [DOI: 10.1111/j.1755-3768.2017.03122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- S. Allgeier
- Institute for Applied Computer Science; Karlsruhe Institute of Technology KIT; Eggenstein-Leopoldshafen Germany
| | - K.M. Reichert
- Institute for Applied Computer Science; Karlsruhe Institute of Technology KIT; Eggenstein-Leopoldshafen Germany
| | - O. Stachs
- Department of Ophthalmology; University of Rostock; Rostock Germany
| | - B. Köhler
- Institute for Applied Computer Science; Karlsruhe Institute of Technology KIT; Eggenstein-Leopoldshafen Germany
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Abstract
In this paper we address critical issues concerning calibration of AFM based methods used for nanoscale mechanical characterization of materials. It has been shown that calibration approaches based on macroscopic models for contact mechanics may yield excellent results in terms of the indentation modulus of the sample, but fail to provide a comprehensive and actual information concerning the tip-sample contact radius or the mechanical properties of the tip. Explanations for the severely reduced indentation modulus of the tip included the inadequacies of the models used for calculations of the tip-sample contact stiffness, discrepancies in the actual and ideal shape of the tip, presence of the amorphous silicon phase within the silicon tip, as well as negligence of the actual size of the stress field created in the tip during elastic interactions. To clarify these issues, we investigated the influence of the mechanical load applied to four AFM silicon tips on their crystalline state by exposing them to systematically increasing loads, evaluating the character of the tip-sample interactions via the load-unload stiffness curves, and assessing the state of the tips from HR-TEM images. The results presented in this paper were obtained in a series of relatively simple and basic atomic force acoustic microscopy (AFAM) experiments. The novel combination of TEM imaging of the AFM tips with the analysis of the load-unload stiffness curves gave us a detailed insight into their mechanical behavior under load conditions. We were able to identify the limits for the elastic interactions, as well as the hallmarks for phase transformation and dislocation formation and movement. The comparison of the physical dimensions of the AFM tips, geometry parameters determined from the values of the contact stiffness, and the information on the crystalline state of the tips allowed us a better understanding of the nanoscale contact.
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Affiliation(s)
- M Kopycinska-Mueller
- Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Maria-Reiche Str. 2, 01109 Dresden, Germany
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Riede S, Toboldt A, Breves G, Metzner M, Köhler B, Bräunig J, Schafft H, Lahrssen-Wiederholt M, Niemann L. Investigations on the possible impact of a glyphosate-containing herbicide on ruminal metabolism and bacteria in vitro by means of the 'Rumen Simulation Technique'. J Appl Microbiol 2016; 121:644-56. [PMID: 27230806 DOI: 10.1111/jam.13190] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 05/20/2016] [Accepted: 05/22/2016] [Indexed: 11/30/2022]
Abstract
AIMS This study was performed in a well-established in vitro model to investigate whether the application of a glyphosate-containing herbicide might affect the bacterial communities and some biochemical parameters in a cow's rumen. METHODS AND RESULTS The test item was applied in two concentrations (high and low) for 5 days. In a second trial, fermentation vessels were inoculated with Clostridium sporogenes before the high dose was applied. Effluents were analysed by biochemical, microbiological and genetic methods. A marginal increase in short-chain fatty acid production and a reduction in NH3 -N were observed. There were minor and rather equivocal changes in the composition of ruminal bacteria but no indications of a shift towards a more frequent abundance of pathogenic Clostridia species. Clostridium sporogenes counts declined consistently. CONCLUSIONS No adverse effects of the herbicide on ruminal metabolism or composition of the bacterial communities could be detected. In particular, there was no evidence of a suspected stimulation of Clostridia growth. SIGNIFICANCE AND IMPACT OF THE STUDY Antibiotic activity of glyphosate resulting in microbial imbalances has been postulated. In this exploratory study, however, intraruminal application of concentrations reflecting potential exposure of dairy cows or beef cattle did not exhibit significant effects on bacterial communities in a complex in vitro system. The low number of replicates (n = 3/dose) may leave some uncertainty.
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Affiliation(s)
- S Riede
- Department of Physiology, University of Veterinary Medicine, Hannover, Germany
| | - A Toboldt
- Federal Institute for Risk Assessment, Berlin, Germany
| | - G Breves
- Department of Physiology, University of Veterinary Medicine, Hannover, Germany
| | | | - B Köhler
- RIPAC-LABOR GmbH, Potsdam, Germany
| | - J Bräunig
- Federal Institute for Risk Assessment, Berlin, Germany
| | - H Schafft
- Federal Institute for Risk Assessment, Berlin, Germany
| | | | - L Niemann
- Federal Institute for Risk Assessment, Berlin, Germany
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Abstract
An investigation regarding possible artefacts from dental filling materials in MR imaging is presented including 9 types of such materials from various manufacturers. Freshly extracted teeth were prepared and the filling materials were handled according to manufacturers' instructions. The teeth were encapsulated into a gel phantom based on de-ionized water, Ni (NO3)2 and polysaccharide agarose powder. The investigation was performed with a standard head coil and a 1.5 T MR unit. Images acquired with various combinations of parameters from different sequences were visually analysed regarding possible artefacts. The investigation showed that only one of the materials caused significant artefacts. The gel phantom was found to be a valuable means for examination of artefacts from small samples, and can be recommended as a standard technique for this purpose.
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Affiliation(s)
- B. Vikhoff
- Departments of Radiation Physics and Diagnostic Radiology, Sahlgren's Hospital, and the Departments of Dental Technology and Oral Pathology, Section of Forensic Odontology, Faculty of Odontology, University of Gothenburg, Gothenburg, Sweden
| | - S. Ribbelin
- Departments of Radiation Physics and Diagnostic Radiology, Sahlgren's Hospital, and the Departments of Dental Technology and Oral Pathology, Section of Forensic Odontology, Faculty of Odontology, University of Gothenburg, Gothenburg, Sweden
| | - B. Köhler
- Departments of Radiation Physics and Diagnostic Radiology, Sahlgren's Hospital, and the Departments of Dental Technology and Oral Pathology, Section of Forensic Odontology, Faculty of Odontology, University of Gothenburg, Gothenburg, Sweden
| | - S. Ekholm
- Departments of Radiation Physics and Diagnostic Radiology, Sahlgren's Hospital, and the Departments of Dental Technology and Oral Pathology, Section of Forensic Odontology, Faculty of Odontology, University of Gothenburg, Gothenburg, Sweden
| | - H. Borrman
- Departments of Radiation Physics and Diagnostic Radiology, Sahlgren's Hospital, and the Departments of Dental Technology and Oral Pathology, Section of Forensic Odontology, Faculty of Odontology, University of Gothenburg, Gothenburg, Sweden
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Nieschlag E, Ferlin A, Gravholt CH, Gromoll J, Köhler B, Lejeune H, Rogol AD, Wistuba J. The Klinefelter syndrome: current management and research challenges. Andrology 2016; 4:545-9. [DOI: 10.1111/andr.12208] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 03/31/2016] [Accepted: 04/01/2016] [Indexed: 11/30/2022]
Affiliation(s)
- E. Nieschlag
- Centre of Reproductive Medicine and Andrology; University of Münster; Münster Germany
- Centre of Excellence in Genomic Medicine Research; King Abdulaziz University; Jeddah Saudi Arabia
| | - A. Ferlin
- Unit of Andrology and Reproductive Medicine; Department of Medicine; University of Padova; Padova Italy
| | - C. H. Gravholt
- Department of Endocrinology and Internal Medicine; Aarhus University Hospital; Aarhus Denmark
| | - J. Gromoll
- Centre of Reproductive Medicine and Andrology; University of Münster; Münster Germany
| | - B. Köhler
- Department of Pediatric Endocrinology; Charité University; Berlin Germany
| | - H. Lejeune
- Service de Médecine de la Reproduction; Hôpital Femme-Mère-Enfant; Université Claude-Bernard; Lyon France
| | - A. D. Rogol
- Department of Pediatrics; School of Medicine; University of Virginia; Charlottesville VA USA
| | - J. Wistuba
- Centre of Reproductive Medicine and Andrology; University of Münster; Münster Germany
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Köhler B, Kloos C, Kißler H, Bärthel E, Raack S, Müller UA, Wolf G. Monozentrische Evaluation des Gewichtsverlaufs unter konservativem Abnehmversuch und nachfolgender laparoskopischer Schlauchmagen Operation. DIABETOL STOFFWECHS 2016. [DOI: 10.1055/s-0036-1580949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Nakahata K, Sugahara H, Barth M, Köhler B, Schubert F. Three dimensional image-based simulation of ultrasonic wave propagation in polycrystalline metal using phase-field modeling. Ultrasonics 2016; 67:18-29. [PMID: 26773789 DOI: 10.1016/j.ultras.2015.12.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 11/13/2015] [Accepted: 12/22/2015] [Indexed: 06/05/2023]
Abstract
When modeling ultrasonic wave propagation in metals, it is important to introduce mesoscopic crystalline structures because the anisotropy of the crystal structure and the heterogeneity of grains disturb ultrasonic waves. In this paper, a three-dimensional (3D) polycrystalline structure generated by multiphase-field modeling was introduced to ultrasonic simulation for nondestructive testing. 3D finite-element simulations of ultrasonic waves were validated and compared with visualization results obtained from laser Doppler vibrometer measurements. The simulation results and measurements showed good agreement with respect to the velocity and front shape of the pressure wave, as well as multiple scattering due to grains. This paper discussed the applicability of a transversely isotropic approach to ultrasonic wave propagation in a polycrystalline metal with columnar structures.
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Affiliation(s)
- K Nakahata
- Department of Civil and Environmental Engineering, Ehime University, 3 Bunkyo, Matsuyama, Ehime 790-8577, Japan.
| | - H Sugahara
- Department of Civil and Environmental Engineering, Ehime University, 3 Bunkyo, Matsuyama, Ehime 790-8577, Japan
| | - M Barth
- Fraunhofer Institute for Ceramic Technologies and Systems - Branch Materials Diagnostics, Maria-Reiche-Strasse 2, 01109 Dresden, Germany
| | - B Köhler
- Fraunhofer Institute for Ceramic Technologies and Systems - Branch Materials Diagnostics, Maria-Reiche-Strasse 2, 01109 Dresden, Germany
| | - F Schubert
- Fraunhofer Institute for Ceramic Technologies and Systems - Branch Materials Diagnostics, Maria-Reiche-Strasse 2, 01109 Dresden, Germany
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Kopycinska-Müller M, Clausner A, Yeap KB, Köhler B, Kuzeyeva N, Mahajan S, Savage T, Zschech E, Wolter KJ. Mechanical characterization of porous nano-thin films by use of atomic force acoustic microscopy. Ultramicroscopy 2016; 162:82-90. [DOI: 10.1016/j.ultramic.2015.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 09/29/2015] [Accepted: 12/03/2015] [Indexed: 10/22/2022]
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Subhani MA, Köhler B, Gürtler C, Leitner W, Müller TE. Light-mediated curing of CO2-based unsaturated polyethercarbonates via thiol–ene click chemistry. Polym Chem 2016. [DOI: 10.1039/c6py00458j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Facile cross-linking of CO2-based unsaturated polyethercarbonates with polymercaptanes via thiol–ene click chemistry makes them highly interesting sustainable pre-polymers for material applications.
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Affiliation(s)
- M. A. Subhani
- CAT Catalytic Center
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - B. Köhler
- CAT Catalytic Center
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - C. Gürtler
- Covestro Deutschland AG
- 51365 Leverkusen
- Germany
| | - W. Leitner
- Lehrstuhl für Technische Chemie und Petrolchemie
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - T. E. Müller
- Lehrstuhl für Technische Chemie und Petrolchemie
- RWTH Aachen University
- 52074 Aachen
- Germany
- Covestro Deutschland AG
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Grothoff M, Etz C, Preim B, Köhler B, Gutberlet M. Phase contrast 4D flow in bicuspid aortic valves in a porcine model. J Cardiovasc Magn Reson 2015. [PMCID: PMC4328401 DOI: 10.1186/1532-429x-17-s1-p416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Köhler B, Preim U, Grothoff M, Gutberlet M, Fischbach K, Preim B. Motion-aware stroke volume quantification in 4D PC-MRI data of the human aorta. Int J Comput Assist Radiol Surg 2015; 11:169-79. [DOI: 10.1007/s11548-015-1256-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 06/30/2015] [Indexed: 12/01/2022]
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Köhler B, Allgeier S, Eberle F, Maier S, Peschel S, Reichert KM, Stachs O. Großflächige Abbildung kornealer Nervenfasern durch geführte Augenbewegungen. Klin Monbl Augenheilkd 2014; 231:1170-3. [DOI: 10.1055/s-0034-1383331] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- B. Köhler
- Karlsruher Institut für Technologie (KIT), Institut für Angewandte Informatik, Karlsruhe
| | - S. Allgeier
- Karlsruher Institut für Technologie (KIT), Institut für Angewandte Informatik/Automatisierungstechnik, Karlsruhe
| | - F. Eberle
- Karlsruher Institut für Technologie (KIT), Institut für Angewandte Informatik, Karlsruhe
| | - S. Maier
- Karlsruher Institut für Technologie (KIT), Institut für Angewandte Informatik/Automatisierungstechnik, Karlsruhe
| | - S. Peschel
- Klinik und Poliklinik für Augenheilkunde, Universität Rostock
| | - K.-M. Reichert
- Karlsruher Institut für Technologie (KIT), Institut für Angewandte Informatik, Karlsruhe
| | - O. Stachs
- Klinik und Poliklinik für Augenheilkunde, Universität Rostock
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Abstract
HISTORY AND CLINICAL PRESENTATION A 65-year-old man with type 2 diabetes mellitus and unfavorable metabolic values in combination with obesity and arterial hypertension and considerable psychosocial strains presented at a psychosomatic outpatient clinic. During the course of diagnostic sessions a problematic illness behavior as well as a depressive symptomatology that had developed after the death of his wife a few years earlier became apparent. DIAGNOSIS, THERAPY, COURSE: An avoidant illness behavior and a moderate depressive episode were diagnosed. Within a low threshold psychosomatic intervention an understanding of illness could be established and psychosocial barriers of diabetes therapy were reduced. The patient was able to outline achievable goals of his diabetes treatment and began their successful implementation. Within a stepped-care approach the patient could also be motivated for an inpatient psychosomatic treatment. During the course of treatment the patient experienced a remission from his depressive symptomatology and a notable improvement of metabolic values. CONCLUSIONS With the help of a close cooperation between diabetes specific and psychotherapeutic treatment in psychosomatic outpatient clinics, patients with high blood glucose levels and comorbid depression can be enabled to gain a better understanding of their illness behavior and change it in their favor.
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Affiliation(s)
- B Köhler
- Klinik für Psychosomatische Medizin und Psychotherapie, Universitätsklinikum Gießen und Marburg GmbH - Standort Gießen, Justus-Liebig-Universität Gießen
| | - J Kruse
- Klinik für Psychosomatische Medizin und Psychotherapie, Universitätsklinikum Gießen und Marburg GmbH - Standort Gießen, Justus-Liebig-Universität Gießen
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Köhler B, Lingemann J, Isler M, Passweg D, Weinreich G, Teschler H. Fehlendes Problembewusstsein für Inkontinenz-Symptome und ungenutzte medizinische Versorgung bei Männern und Frauen mit chronisch obstruktiver Lungenerkrankung (COPD). Pneumologie 2014. [DOI: 10.1055/s-0034-1367826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Köhler B, Gasteiger R, Preim U, Theisel H, Gutberlet M, Preim B. Semi-automatic vortex extraction in 4D PC-MRI cardiac blood flow data using line predicates. IEEE Trans Vis Comput Graph 2013; 19:2773-2782. [PMID: 24051844 DOI: 10.1109/tvcg.2013.189] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Cardiovascular diseases (CVD) are the leading cause of death worldwide. Their initiation and evolution depends strongly on the blood flow characteristics. In recent years, advances in 4D PC-MRI acquisition enable reliable and time-resolved 3D flow measuring, which allows a qualitative and quantitative analysis of the patient-specific hemodynamics. Currently, medical researchers investigate the relation between characteristic flow patterns like vortices and different pathologies. The manual extraction and evaluation is tedious and requires expert knowledge. Standardized, (semi-)automatic and reliable techniques are necessary to make the analysis of 4D PC-MRI applicable for the clinical routine. In this work, we present an approach for the extraction of vortex flow in the aorta and pulmonary artery incorporating line predicates. We provide an extensive comparison of existent vortex extraction methods to determine the most suitable vortex criterion for cardiac blood flow and apply our approach to ten datasets with different pathologies like coarctations, Tetralogy of Fallot and aneurysms. For two cases we provide a detailed discussion how our results are capable to complement existent diagnosis information. To ensure real-time feedback for the domain experts we implement our method completely on the GPU.
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Winter K, Allgeier S, Eberle F, Köhler B, Maier S, Stachs O, Bretthauer G. Software-Based Imaging and Segmentation of Corneal Nerve Fibres. ACTA ACUST UNITED AC 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-L/bmt-2013-4293/bmt-2013-4293.xml. [PMID: 24042934 DOI: 10.1515/bmt-2013-4293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Allgeier S, Eberle F, Köhler B, Maier S, van Wezel J, Zhivov A, Bretthauer G. A Confocal Microscopy Study of the Anterior Corneal Mosaic in the Sub-Basal Nerve Plexus. ACTA ACUST UNITED AC 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-L/bmt-2013-4270/bmt-2013-4270.xml. [PMID: 24042953 DOI: 10.1515/bmt-2013-4270] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Kopycinska-Müller M, Yeap KB, Mahajan S, Köhler B, Kuzeyeva N, Müller T, Zschech E, Wolter KJ. Mechanical characterization of nanoporous materials by use of atomic force acoustic microscopy methods. Nanotechnology 2013; 24:355703. [PMID: 23938222 DOI: 10.1088/0957-4484/24/35/355703] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We have used the atomic force acoustic microscopy (AFAM) method to determine the indentation modulus of nanoporous thin-film materials with ultralow values of dielectric permittivity (dielectric constant k < 2.4). The AFAM method is based on the contact mode of atomic force microscopy (AFM) and as such is able to characterize materials with high spatial resolution. The tested material was porous organosilicate glass with nominal porosity ranging from 27% to 40%. The values obtained for the indentation modulus varied from 4 to 7 GPa depending on the pore concentration. The values obtained for the indentation modulus by use of the AFAM method were in very good agreement with those determined by nanoindentation. In addition, a part of the AFAM results obtained for the sample with the highest porosity content showed dependence of the effective indentation modulus on the applied load. Preliminary data analysis suggests that the stress rate is the critical factor in triggering this particular mechanical response of the porous material.
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Affiliation(s)
- M Kopycinska-Müller
- Faculty of Electrical Engineering and Information Technology, Technical University Dresden, Helmholtz Straße 18, D-01069 Dresden, Germany.
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Köhler B, Lingemann J, Lüder C, Weinreich G, Teschler H. Prävalenz und Symptomschwere von Harninkontinenz (HI) bei Männern und Frauen mit chronisch obstruktiver Lungenerkrankung (COPD). Pneumologie 2013. [DOI: 10.1055/s-0033-1334657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
OBJECTIVES Evaluation of dogs with elevated plasma thyroxine concentration fed raw food before and after changing the diet. METHOD Between 2006 and 2011 all dogs presented with an elevated plasma thyroxine concentration and a dietary history of feeding raw food were included. Thyroxine (reference interval: 19·3 to 51·5 nmol/L) and in many cases also thyroid-stimulating hormone concentrations (reference interval: <0·30 ng/mL) were measured initially and after changing the diet. RESULTS Twelve dogs were presented with a median age of five years. The median plasma thyroxine concentration was 156·1 (range of 79·7 to 391·9) nmol/L; in six dogs, thyroid-stimulating hormone concentration was measured and was <0·03 ng/mL in five dogs and 0·05 ng/mL in one dog. Six dogs showed clinical signs such as weight loss, aggressiveness, tachycardia, panting and restlessness while six dogs had no clinical signs. After changing the diet eight dogs were examined: thyroxine concentration normalised in all dogs and clinical signs resolved. CLINICAL SIGNIFICANCE Dietary hyperthyroidism can be seen in dogs on a raw meat diet or fed fresh or dried gullets. Increased plasma thyroxine concentration in a dog, either with or without signs of hyperthyroidism, should prompt the veterinarian to obtain a thorough dietary history.
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Affiliation(s)
- B Köhler
- Small Animal Clinic Hofheim, Im Langgewann 9, 65719 Hofheim, Germany
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Köhler B, Allgeier S, Eberle F, Reichert K, Stachs O, Bretthauer G. Generating extended images of the corneal nerve plexus by guided eye movements. BIOMED ENG-BIOMED TE 2012. [DOI: 10.1515/bmt-2012-4202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- B. Köhler
- Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - S. Allgeier
- Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - F. Eberle
- Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - K. Reichert
- Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - O. Stachs
- University of Rostock, Rostock, Germany
| | - G. Bretthauer
- Karlsruhe Institute of Technology, Karlsruhe, Germany
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Allgeier S, Eberle F, Köhler B, Maier S, Zhivov A, Bretthauer G. Mosaicking images of the corneal sub-basal nerve plexus using hierarchical block-based image registration. BIOMED ENG-BIOMED TE 2012. [DOI: 10.1515/bmt-2012-4201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- S. Allgeier
- Institute for Applied Computer Science/Automation, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - F. Eberle
- Institute for Applied Computer Science, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - B. Köhler
- Institute for Applied Computer Science, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - S. Maier
- Institute for Applied Computer Science/Automation, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - A. Zhivov
- Department of Ophthalmology, University of Rostock, Rostock, Germany
| | - G. Bretthauer
- Institute for Applied Computer Science/Automation, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- Institute for Applied Computer Science, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
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Köhler B, Andréen I. Mutans streptococci and caries prevalence in children after early maternal caries prevention: a follow-up at 19 years of age. Caries Res 2012; 46:474-80. [PMID: 22796731 DOI: 10.1159/000339665] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 05/22/2012] [Indexed: 11/19/2022] Open
Abstract
AIM The efficacy of early maternal caries prevention was evaluated. Furthermore, the difference between children colonised with mutans streptococci (MS) at an early or late stage with regard to the prevalence of carious lesions was determined. METHODS The children of first-time mothers selected on the basis of high salivary levels of MS for participation in a caries prevention programme were recalled at the age of 19 years. They were examined for salivary MS, lesion prevalence (decayed and filled surfaces, DFS) and MS in plaque from 12 selected proximal surfaces. RESULTS The recall rate was 70% for the children of both the high-control and interventional groups. All high-control children and 67% of the interventional children were colonised by MS. All the children with non-detectable MS in saliva were also negative in all plaque samples. No statistically significant difference was found between the groups in terms of DFS, although more interventional children were caries free than in the control group. Early-colonised children, irrespective of group identity, had higher salivary MS levels and DFS than later MS-colonised children. CONCLUSION The results indicate that it is possible to remain negative for MS into adulthood if non-colonised at an early age and this affects the development of carious lesions. Strategies for the prevention of dental caries in early childhood should, therefore, include measures to prevent or delay early colonisation by cariogenic bacteria.
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Affiliation(s)
- B Köhler
- Department of Cariology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
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Kopycinska-Müller M, Striegler A, Schlegel R, Kuzeyeva N, Köhler B, Wolter KJ. Dual resonance excitation system for the contact mode of atomic force microscopy. Rev Sci Instrum 2012; 83:043703. [PMID: 22559535 DOI: 10.1063/1.3702799] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We propose an improved system that enables simultaneous excitation and measurements of at least two resonance frequency spectra of a vibrating atomic force microscopy (AFM) cantilever. With the dual resonance excitation system it is not only possible to excite the cantilever vibrations in different frequency ranges but also to control the excitation amplitude for the individual modes. This system can be used to excite the resonance frequencies of a cantilever that is either free of the tip-sample interactions or engaged in contact with the sample surface. The atomic force acoustic microscopy and principally similar methods utilize resonance frequencies of the AFM cantilever vibrating while in contact with the sample surface to determine its local elastic modulus. As such calculation demands values of at least two resonance frequencies, two or three subsequent measurements of the contact resonance spectra are necessary. Our approach shortens the measurement time by a factor of two and limits the influence of the AFM tip wear on the values of the tip-sample contact stiffness. In addition, it allows for in situ observation of processes transpiring within the AFM tip or the sample during non-elastic interaction, such as tip fracture.
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Affiliation(s)
- M Kopycinska-Müller
- Faculty of Electrical Engineering and Information Technology, Technische Universität Dresden, Helmholtz Str. 18, 01069 Dresden, Germany
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Köhler B, Allgeier S, Eberle F, Guthoff R, Maier S, Stachs O, Zhivov A, Ziegler D, Bretthauer G. [Image reconstruction of the corneal subbasal nerve plexus with extended field of view from focus image stacks of a confocal laser scanning microscope]. Klin Monbl Augenheilkd 2011; 228:1060-6. [PMID: 22167357 DOI: 10.1055/s-0031-1281959] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
BACKGROUND Confocal laser scanning microscopy (CLSM) allows the in vivo analysis of nerve structures of the human cornea. In this way, pathological alterations of the peripheral nervous system that also affect the corneal subbasal nerve plexus (SNP) can be diagnosed non-invasively and possibly earlier than with other methods. The field of view of in vivo CLSM images of the cornea (ca. 0.4 × 0.4 mm²) is not sufficient for a reliable assessment. Two phenomena make the image assessment difficult: the presence of ridge-like tissue deformations in the neighbourhood of the SNP and image distortions that are induced by involuntary and unavoidable eye movements during image acquisition. This paper presents an image processing method for generating undistorted images of the SNP with an extended field of view. METHODS The presented method has been tested on five volunteers. Eight focus image stacks have been taken and processed from each subject using a Heidelberg Retina Tomograph with Rostock Cornea Module (HRT). An image registration scheme specifically adapted to the image acquisition system corrects the non-linear motion-induced image distortions and reconstructs a volume from each focus image stack. The epithelial basal boundary surface including the SNP appears as a distinctive hyper-reflective layer inside the reconstructed volume. Extracting this continuous layer generates a depth map and finally a two-dimensional image of the SNP. A final fusion step of the single reconstructed SNP images leads to laterally extended images. RESULTS Out of 40 focus image stacks, 34 have been fully processed into two-dimensional SNP reconstruction images. Six focus image stacks could not be transformed into volumes because of extremely fast eye movements during the image acquisition that prevented the complete image registration of the stacks. The 34 SNP reconstruction images depict an average area of 94.7 % ( ± 6.2 %) with respect to the field of view of a single HRT image. The final fusion of the reconstructed images resulted in an average increase of the image area by a factor of 2.6 (ranging from 2.2 to 3.1). CONCLUSION The presented image processing algorithms are capable of correcting the motion-induced image distortions and of generating larger two-dimensional images of the SNP even in presence of severe tissue deformations. These images provide the basis for a more reliable assessment of the corneal nerve fibres.
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Affiliation(s)
- B Köhler
- Institut für Angewandte Informatik, Karlsruher Institut für Technologie (KIT).
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Bankel M, Robertson A, Köhler B. Carious lesions and caries risk predictors in a group of Swedish children 2 to 3 years of age. One year observation. Eur J Paediatr Dent 2011; 12:215-219. [PMID: 22185243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
AIM Identification of potential carious risk criteria, retrospectively at 2 years of age, for developing carious lesions at 3 years of age. Study design Longitudinal observations from 2 until 3 years of age. Cross-sectional observations of two cohorts of 3- year-olds with different approaches. MATERIALS AND METHODS The study group consisted of 78 three- year- olds from a previous study at age 2 years. Clinical examination, diet history, questions regarding breastfeeding and salivary sampling for mutans streptococci (MS) were performed at both ages. The previous study on 124 three-year-olds was used as a control group for comparison of the 3-year-olds in the longitudinal study group. RESULTS The examinations suggested the following risk predictors: carious lesions, frequent intake of selected sugar-containing products, breastfeeding at night and MS, which covered all children with lesions at 3 years of age, resulting in a positive predictive value of 32% and a negative predictive value of 100%. The only statistically significant difference between the two groups of 3-year-olds was the reported intake of sugar-containing items. Statistics Student's t-test and chi square test, completed by Fischer's exact test. CONCLUSION The combination of the suggested risk criteria was predictive of carious lesions. In spite of individual parental information, new lesions developed after one year. Based on observations, a more structured and monitored preventive approach is suggested.
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Affiliation(s)
- M Bankel
- Public Dental Health Service Kungälv, Public Dental Health, Gothenburg, Sweden
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Köhler B, Biebermann H, Friedsam V, Gellermann J, Maier RF, Pohl M, Wieacker P, Hiort O, Grüters A, Krude H. Analysis of the Wilms' tumor suppressor gene (WT1) in patients 46,XY disorders of sex development. J Clin Endocrinol Metab 2011; 96:E1131-6. [PMID: 21508141 DOI: 10.1210/jc.2010-2804] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
CONTEXT The Wilms' tumor suppressor gene (WT1) is one of the major regulators of early gonadal and kidney development. WT1 mutations have been identified in 46,XY disorders of sex development (DSD) with associated kidney disease and in few isolated forms of 46,XY DSD. OBJECTIVE The objective of the study was the evaluation of WT1 mutations in different phenotypes of isolated 46,XY DSD and clinical consequences. DESIGN The design of the study was: 1) sequencing of the WT1 gene in 210 patients with 46,XY DSD from the German DSD network, consisting of 150 males with severe hypospadias (70 without cryptorchidism, 80 with at least one cryptorchid testis), 10 males with vanishing testes syndrome, and 50 raised females with partial to complete 46,XY gonadal dysgenesis; and 2) genotype-phenotype correlation of our and all published patients with 46,XY DSD and WT1 mutations. RESULTS We have detected WT1 mutations in six of 80 patients with severe hypospadias (7.5%) and at least one cryptorchid testis and in one of 10 patients with vanishing testes syndrome (10%). All patients except one developed Wilms' tumor and/or nephropathy in childhood or adolescence. CONCLUSION WT1 analysis should be performed in newborns with complex hypospadias with at least one cryptorchid testis and in isolated 46,XY partial to complete gonadal dysgenesis. Kidney disease might not develop until later life in these cases. WT1 analysis is mandatory in all 46,XY DSD with associated kidney disease. WT1 analysis is not indicated in newborns with isolated hypospadias without cryptorchidism. Patients with WT1 mutations should be followed up closely because the risk of developing a Wilms' tumor, nephropathy, and/or gonadal tumor is very high.
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Affiliation(s)
- B Köhler
- Department of Pediatric Endocrinology, University Children's Hospital, Charité, Augustenburger Platz 1, 13353 Berlin, Germany.
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Köhler B, Achermann JC. Update--steroidogenic factor 1 (SF-1, NR5A1). MINERVA ENDOCRINOL 2010; 35:73-86. [PMID: 20595937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Steroidogenic factor 1 (SF1, NR5A1, Ad4BP) is a nuclear receptor and regulator of multiple genes involved in adrenal and gonadal development, steroidogenesis, and the reproductive axis. Complete deletion of Nr5a1 in XY mice results in adrenal and gonadal agenesis, female external genitalia and presence of Müllerian structures. These findings were first reported in the early 1990s. Subsequently, NR5A1 mutations were found in two 46,XY phenotypic females with Müllerian structures and adrenal failure and in one 46,XX female with adrenal failure. More recently, heterozygous NR5A1 mutations have been identified in a substantial proportion of patients with 46,XY disorders of sex development (46,XY DSD) without adrenal insufficiency. Most of these individuals display severe underandrogenization with ambiguous genitalia at birth, partial gonadal dysgenesis, and absence of Müllerian structures or remnants. Some of the patients have a milder phenotype such as hypospadias and cryptorchidism, due to less severe defects in androgen synthesis. Testosterone, inhibin B and AMH are usually low indicating a partial (or sometimes progressive) form of gonadal dysgenesis in most cases. However, normal testosterone production at birth might also be present. The frequency of NR5A1 mutations in otherwise unexplained 46,XY DSD with underandrogenization and partial testicular dysgenesis has been estimated to be about 15%. Furthermore, NR5A1 mutations have now been found in women with familial and sporadic 46,XX primary ovarian insufficiency without adrenal failure. These human phenotypes associated with NR5A1 mutations show that SF-1 is a key factor involved in both human testis and ovarian development, but that human adrenal development seems to be more resistant to the effects of SF-1 haploinsufficiency than gonadal development. Patients with 46,XY DSD and mild underandrogenization due to partial testicular dysgenesis should possibly be assigned to the male sex, as small testes with Leydig, Sertoli and germ cells are present in almost all cases. Additionally, spontaneous virilization in puberty might be possible in patients with NR5A1 mutations. However, fertility options and the risk of testicular malignancy and adrenal insufficiency in adulthood are unknown and need to be investigated in long-term outcome studies.
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Affiliation(s)
- B Köhler
- Department of Pediatric Endocrinology, University Children's Hospital, Charité, Humboldt University, Augustenburger Platz 1, Berlin, Germany.
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Köhler B, Imhof E, Teschler H. Harninkontinenz bei Patientinnen mit Cystischer Fibrose. Pneumologie 2010. [DOI: 10.1055/s-0030-1251253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Köhler B, Andréen I. Mutans Streptococci and Caries Prevalence in Children after Early Maternal Caries Prevention: A Follow-Up at Eleven and Fifteen Years of Age. Caries Res 2010; 44:453-8. [DOI: 10.1159/000320168] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Accepted: 07/30/2010] [Indexed: 11/19/2022] Open
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Grüters A, Köhler B, Wolf A, Söling A, de Vijlder L, Krude H, Biebermann H. Screening for mutations of the human thyroid peroxidase gene in patients with congenital hypothyroidism. Exp Clin Endocrinol Diabetes 2009; 104 Suppl 4:121-3. [PMID: 8981018 DOI: 10.1055/s-0029-1211718] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
While congenital hypothyroidism in 80-90% of the affected individuals is caused by thyroid dysgenesis (athyrosis, ectopy or hypoplasia), hypothyroidism in patients with a thyroid gland of normal position and size can be due to regulatory or enzymatic defects of thyroid hormone biosynthesis. Beside defects of thyroglobulinsynthesis, defects of the sodium-iodide-transporter or the TSH-receptor, a defect of the thyroidperoxidase, the key-enzyme of thyroid hormone biosynthesis, can cause a total iodide organification defect and thereby congenital hypothyroidism. We screened 14 of 103 patients (13.6%) with non familial congenital hypothyroidism and a normally developed thyroid gland detected by the newborn screening program with the PCR-SSCP (single-stranded-conformational-polymorphism) technique for mutations in the exons 2, 8, 9, 10 and 14 of the human thyroperoxidase gene, and in which mutations had been described previously in Dutch and Brazilian families with total organification defects. Most of the previously reported mutations were found in exons 8, 9 and 10 which code for the caralytic part of the enzyme. In two patients a GGCC-duplication in exon 8 was detected leading to a premature stop codon in exon 9. While one patient without neonatal goiter was homozygous for this mutation, the second patient was only heterozygous thus demanding another mutation on the second TPO-allel to explain the phenotype. Since the GGCC duplication is easily demonstrable by a NaeI digestion, because it creates a restriction site for this enzyme, screening for this mutation is indicated since it is easy to perform. In contrast to the perchlorate discharge test molecular genetic studies are less invasive, but as useful in making a definitive diagnosis in the individual patient. Furthermore it is the first feasible step to study the etiology and epidemiology of the so far only putative defects of thyroid hormone biosynthesis leading to congenital hypothyroidism.
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Affiliation(s)
- A Grüters
- Department of Pediatrics, Humboldt University Berlin, Germany
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Abstract
We show that it is possible to prepare and identify ultra-thin sheets of graphene on crystalline substrates such as SrTiO(3), TiO(2), Al(2)O(3) and CaF(2) by standard techniques (mechanical exfoliation, optical and atomic force microscopy). On the substrates under consideration we find a similar distribution of single layer, bilayer and few-layer graphene and graphite flakes as with conventional SiO(2) substrates. The optical contrast C of a single graphene layer on any of those substrates is determined by calculating the optical properties of a two-dimensional metallic sheet on the surface of a dielectric, which yields values between C = -1.5% (G/TiO(2)) and C = -8.8% (G/CaF(2)). This contrast is in reasonable agreement with experimental data and is sufficient to make identification by an optical microscope possible. The graphene layers cover the crystalline substrate in a carpet-like mode and the height of single layer graphene on any of the crystalline substrates as determined by atomic force microscopy is d(SLG) = 0.34 nm and thus much smaller than on SiO(2).
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Affiliation(s)
- S Akcöltekin
- Fachbereich Physik, CeNIDE, Universität Duisburg-Essen, D-47048 Duisburg, Germany
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48
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Schubert L, Barth M, Klesse T, Köhler B, Frankenstein B. Guided elastic waves and their impact interaction in CFRP structures characterized by 3D laser scanning vibrometry. ACTA ACUST UNITED AC 2008. [DOI: 10.1117/12.777510] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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49
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Grosskreutz J, Köhler B, Dengler R, Becker H, Peschel T. Affektion des somatosensorischen und visuellen Systems bei der zervikalen Dystonie in der Kernspinmorphometrie. KLIN NEUROPHYSIOL 2007. [DOI: 10.1055/s-2007-976360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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50
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Peuser P, Platz W, Zeller P, Brand T, Haag M, Köhler B. High-power, longitudinally fiber-pumped, passively Q-switched Nd:YAG oscillator-amplifier. Opt Lett 2006; 31:1991-3. [PMID: 16770409 DOI: 10.1364/ol.31.001991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
A longitudinally fiber-pumped, passively Q-switched Nd:YAG laser oscillator-power amplifier system is reported with which a maximum pulse energy of 68 mJ was achieved at high pulse stability, beam quality, and efficiency. Therefore, a compact fiber-coupling interface was developed for stacked arrays of quasi-cw diode lasers, providing a pump power of 1 kW at the fiber end.
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Affiliation(s)
- P Peuser
- EADS Deutschland GmbH, Corporate Research Centre, LG-OS, München, Germany.
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