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Wilms LM, Radke KL, Abrar DB, Frahm J, Voit D, Thelen S, Klee D, Grunz JP, Müller-Lutz A, Nebelung S. Dynamic assessment of scapholunate ligament status by real-time magnetic resonance imaging: an exploratory clinical study. Skeletal Radiol 2024; 53:791-800. [PMID: 37819279 PMCID: PMC10858828 DOI: 10.1007/s00256-023-04466-6] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 09/25/2023] [Accepted: 09/25/2023] [Indexed: 10/13/2023]
Abstract
OBJECTIVE Clinical-standard MRI is the imaging modality of choice for the wrist, yet limited to static evaluation, thereby potentially missing dynamic instability patterns. We aimed to investigate the clinical benefit of (dynamic) real-time MRI, complemented by automatic analysis, in patients with complete or partial scapholunate ligament (SLL) tears. MATERIAL AND METHODS Both wrists of ten patients with unilateral SLL tears (six partial, four complete tears) as diagnosed by clinical-standard MRI were imaged during continuous active radioulnar motion using a 1.5-T MRI scanner in combination with a custom-made motion device. Following automatic segmentation of the wrist, the scapholunate and lunotriquetral joint widths were analyzed across the entire range of motion (ROM). Mixed-effects model analysis of variance (ANOVA) followed by Tukey's posthoc test and two-way ANOVA were used for statistical analysis. RESULTS With the increasing extent of SLL tear, the scapholunate joint widths in injured wrists were significantly larger over the entire ROM compared to those of the contralateral healthy wrists (p<0.001). Differences between partial and complete tears were most pronounced at 5°-15° ulnar abduction (p<0.001). Motion patterns and trajectories were altered. Complete SLL deficiency resulted in complex alterations of the lunotriquetral joint widths. CONCLUSION Real-time MRI may improve the functional diagnosis of SLL insufficiency and aid therapeutic decision-making by revealing dynamic forms of dissociative instability within the proximal carpus. Static MRI best differentiates SLL-injured wrists at 5°-15° of ulnar abduction.
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Affiliation(s)
- Lena Marie Wilms
- Department of Diagnostic and Interventional Radiology, University Dusseldorf, Medical Faculty, Moorenstrasse 5, D-40225, Dusseldorf, Germany.
| | - Karl Ludger Radke
- Department of Diagnostic and Interventional Radiology, University Dusseldorf, Medical Faculty, Moorenstrasse 5, D-40225, Dusseldorf, Germany
| | - Daniel Benjamin Abrar
- Department of Diagnostic and Interventional Radiology, University Dusseldorf, Medical Faculty, Moorenstrasse 5, D-40225, Dusseldorf, Germany
| | - Jens Frahm
- Biomedical NMR, Max Planck Institute for Multidisciplinary Sciences, D-37077, Goettingen, Germany
| | - Dirk Voit
- Biomedical NMR, Max Planck Institute for Multidisciplinary Sciences, D-37077, Goettingen, Germany
| | - Simon Thelen
- Department of Orthopaedics and Trauma Surgery, Medical Faculty, University Dusseldorf, D-40225, Dusseldorf, Germany
| | - Dirk Klee
- Department of Diagnostic and Interventional Radiology, University Dusseldorf, Medical Faculty, Moorenstrasse 5, D-40225, Dusseldorf, Germany
- Department of General Pediatrics, University Dusseldorf, Medical Faculty, University Children's Hospital, Heinrich-Heine-University Dusseldorf, Moorenstrasse 5, Düsseldorf, Germany
| | - Jan-Peter Grunz
- Department of Diagnostic and Interventional Radiology, University Hospital Wurzburg, D-97080, Würzburg, Germany
| | - Anja Müller-Lutz
- Department of Diagnostic and Interventional Radiology, University Dusseldorf, Medical Faculty, Moorenstrasse 5, D-40225, Dusseldorf, Germany
| | - Sven Nebelung
- Department of Diagnostic and Interventional Radiology, University Dusseldorf, Medical Faculty, Moorenstrasse 5, D-40225, Dusseldorf, Germany
- Department of Diagnostic and Interventional Radiology, University Hospital Aachen, D-52074, Aachen, Germany
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Steuwe A, Ljimani A, Andree M, Wienemann T, Lübke N, Walker A, Ole Jensen BE, The Racoon Study Group, Radke KL, Antoch G, Valentin B. Disease Course and Pulmonary Involvement of COVID-19 during the Delta Variant Period in Germany: A Comparative Study of Vaccinated and Unvaccinated Patients at a Tertiary Hospital. Curr Med Imaging 2024; 20:CMIR-EPUB-138767. [PMID: 38415484 DOI: 10.2174/0115734056282920231212104602] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 11/29/2023] [Accepted: 12/06/2023] [Indexed: 02/29/2024]
Abstract
Background: Despite the availability of vaccines, there is an increasing number of SARS-CoV-2-breakthrough-infections. OBJECTIVE The aim of this study was to determine whether there is a radiological difference in lung parenchymal involvement between infected vaccinated and unvaccinated patients. Additionally, we aimed to investigate whether vaccination has an impact on the course of illness and the need for intensive care. METHODS This study includes all patients undergoing chest computed tomography (CT) or x-ray imaging in case of a proven SARS-CoV-2 infection between September and November 2021. Anonymized CT and x-ray images were reviewed retrospectively and in consensus by two radiologists, applying an internal severity score scheme for CT and x-ray as well as CARE and BRIXIA scores for x-ray. Radiological findings were compared to vaccination status, comorbidities, inpatient course of the patient's illness and the subjective onset of symptoms. RESULTS In total, 38 patients with acute SARS-CoV-2 infection underwent a CT scan, and 168 patients underwent an x-ray examination during the study period. Of these, 32% were vaccinated in the CT group, and 45% in the x-ray group. For the latter, vaccinated patients exhibited significantly more comorbidities (cardiovascular (p=0.002), haemato-oncological diseases (p=0.016), immunosuppression (p=0.004)), and a higher age (p<0.001). Vaccinated groups showed significantly lower extent of lung involvement (severity scores in CT cohort and x-ray cohort both p≤0.020; ARDS 42% in unvaccinated CT cohort vs. 8% in vaccinated CT cohort). Furthermore, vaccinated patients in the CT cohort had significantly less need for intensive care treatment (p=0.040). CONCLUSION Our data suggest that vaccination, in the case of breakthrough infection, favours a milder course of illness concerning lung parenchymal involvement and the need for intensive care, despite negative predictors, such as immunosuppression or other pre-existing conditions..
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Affiliation(s)
- Andrea Steuwe
- Department of Diagnostic and Interventional Radiology, Medical Faculty and University Hospital, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Alexandra Ljimani
- Department of Diagnostic and Interventional Radiology, Medical Faculty and University Hospital, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Marcel Andree
- Institute of Virology, Medical Faculty and University Hospital, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Tobias Wienemann
- Institute of Medical Microbiology and Hospital Hygiene, Medical Faculty and University Hospital, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Nadine Lübke
- Institute of Virology, Medical Faculty and University Hospital, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Andreas Walker
- Institute of Virology, Medical Faculty and University Hospital, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Björn-Erik Ole Jensen
- Department of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty and University Hospital, Heinrich Heine University D-40225 Düsseldorf, Düsseldorf, Germany
| | | | - Karl Ludger Radke
- Department of Diagnostic and Interventional Radiology, Medical Faculty and University Hospital, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Gerald Antoch
- Department of Diagnostic and Interventional Radiology, Medical Faculty and University Hospital, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Birte Valentin
- Department of Diagnostic and Interventional Radiology, Medical Faculty and University Hospital, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
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Boschheidgen M, Schimmöller L, Kastl R, Drewes LR, Jannusch K, Radke KL, Kirchner J, Ullrich T, Niegisch G, Albers P, Antoch G, Radtke JP. MRI characteristics and oncological follow-up of patients with ISUP grade group 4 or 5 prostate cancer. Abdom Radiol (NY) 2024; 49:192-201. [PMID: 37906272 PMCID: PMC10789849 DOI: 10.1007/s00261-023-04073-y] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 09/20/2023] [Accepted: 09/25/2023] [Indexed: 11/02/2023]
Abstract
OBJECTIVES To analyze multiparametric MRI (mpMRI) characteristics of patients with International Society of Urological Pathology (ISUP) grade group (GG) 4 or 5 prostate cancer (PC) and to correlate MRI parameters with the occurrence of biochemical recurrence (BCR) after radical prostatectomy (RPE). METHODS In this single-center cohort study consecutive patients with mpMRI and ISUP GG 4 or 5 PC were retrospectively analyzed. Clinical, MR-guided biopsy, and diagnostic mpMRI parameter were assessed. A subcohort of patients with RPE and follow-up was analyzed separately. A univariate and multivariate analyses were performed to determine parameters that are associated to patients with BCR after RPE. RESULTS 145 patients (mean age 70y, median PSA 10.9 ng/ml) were analyzed. 99% had a PI-RADS classification of 4 or 5, 48% revealed MRI T3 stage, and median diameter of the MRI index lesion (IL) was 15 mm. IL showed a median ADC value of 668 ×10-6 mm2/s and exhibited contrast enhancement in 94% of the cases. For patients with follow-up after RPE (n = 82; mean follow-up time 68 ± 27 m), MRI parameters were significantly different for contact length of the IL to the pseudocapsule (LCC), MRI T3 stage, and IL localization (p < 0.05). Higher PSAD and MRI T3 stage were independent parameters for the risk of BCR when incorporating clinical, biopsy, and MRI parameters. CONCLUSION ISUP GG 4 or 5 PC has distinctive characteristics on mpMRI and were detected on MRI in all cases. In addition, higher PSAD and MRI T3 stage were significant predictors for BCR after RPE.
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Affiliation(s)
- M Boschheidgen
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Dusseldorf, Germany
| | - L Schimmöller
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Dusseldorf, Germany.
- Department of Diagnostic, Interventional Radiology and Nuclear Medicine, Marien Hospital Herne, University Hospital of the Ruhr-University Bochum, Herne, Germany.
| | - R Kastl
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Dusseldorf, Germany
| | - L R Drewes
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Dusseldorf, Germany
| | - K Jannusch
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Dusseldorf, Germany
| | - K L Radke
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Dusseldorf, Germany
| | - J Kirchner
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Dusseldorf, Germany
| | - T Ullrich
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Dusseldorf, Germany
| | - G Niegisch
- Department of Urology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Dusseldorf, Germany
| | - P Albers
- Department of Urology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Dusseldorf, Germany
| | - G Antoch
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Dusseldorf, Germany
| | - J P Radtke
- Department of Urology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Dusseldorf, Germany
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Röwer LM, Radke KL, Hußmann J, Malik H, Eichinger M, Voit D, Wielpütz MO, Frahm J, Klee D, Pillekamp F. First experience with real-time magnetic resonance imaging-based investigation of respiratory influence on cardiac function in pediatric congenital heart disease patients with chronic right ventricular volume overload. Pediatr Radiol 2023; 53:2608-2621. [PMID: 37794175 PMCID: PMC10698081 DOI: 10.1007/s00247-023-05765-9] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 09/03/2023] [Accepted: 09/04/2023] [Indexed: 10/06/2023]
Abstract
BACKGROUND Congenital heart disease (CHD) is often associated with chronic right ventricular (RV) volume overload. Real-time magnetic resonance imaging (MRI) enables the analysis of cardiac function during free breathing. OBJECTIVE To evaluate the influence of respiration in pediatric patients with CHD and chronic RV volume overload. METHODS AND MATERIALS RV volume overload patients (n=6) and controls (n=6) were recruited for cardiac real-time MRI at 1.5 tesla during free breathing. Breathing curves from regions of interest reflecting the position of the diaphragm served for binning images in four different tidal volume classes, each in inspiration and expiration. Tidal volumes were estimated from these curves by data previously obtained by magnetic resonance-compatible spirometry. Ventricular volumes indexed to body surface area and Frank-Starling relationships referenced to the typical tidal volume indexed to body height (TTVi) were compared. RESULTS Indexed RV end-diastolic volume (RV-EDVi) and indexed RV stroke volume (RV-SVi) increased during inspiration (RV-EDVi/TTVi: RV load: + 16 ± 4%; controls: + 22 ± 13%; RV-SVi/TTVi: RV load: + 21 ± 6%; controls: + 35 ± 17%; non-significant for comparison). The increase in RV ejection fraction during inspiration was significantly lower in RV load patients (RV load: + 1.1 ± 2.2%; controls: + 6.1 ± 1.5%; P=0.01). The Frank-Starling relationship of the RV provided a significantly reduced slope estimate in RV load patients (inspiration: RV load: 0.75 ± 0.11; controls: 0.92 ± 0.02; P=0.02). CONCLUSION In pediatric patients with CHD and chronic RV volume overload, cardiac real-time MRI during free breathing in combination with respiratory-based binning indicates an impaired Frank-Starling relationship of the RV.
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Affiliation(s)
- Lena Maria Röwer
- Department of Diagnostic and Interventional Radiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Moorenstr. 5, 40225, Düsseldorf, Germany
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Medical Faculty and University Hospital, Heinrich-Heine-University, Düsseldorf, Germany
| | - Karl Ludger Radke
- Department of Diagnostic and Interventional Radiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Janina Hußmann
- Department of Diagnostic and Interventional Radiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Moorenstr. 5, 40225, Düsseldorf, Germany
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Medical Faculty and University Hospital, Heinrich-Heine-University, Düsseldorf, Germany
| | - Halima Malik
- Department of Diagnostic and Interventional Radiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Moorenstr. 5, 40225, Düsseldorf, Germany
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Medical Faculty and University Hospital, Heinrich-Heine-University, Düsseldorf, Germany
| | - Monika Eichinger
- Department of Diagnostic and Interventional Radiology with Nuclear Medicine, Thoraxklinik at University of Heidelberg, Heidelberg, Germany
- Department of Diagnostic and Interventional Radiology, Subdivision of Pulmonary Imaging, University Hospital of Heidelberg, Heidelberg, Germany
- Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), Heidelberg, Germany
| | - Dirk Voit
- Biomedical NMR, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Mark Oliver Wielpütz
- Department of Diagnostic and Interventional Radiology with Nuclear Medicine, Thoraxklinik at University of Heidelberg, Heidelberg, Germany
- Department of Diagnostic and Interventional Radiology, Subdivision of Pulmonary Imaging, University Hospital of Heidelberg, Heidelberg, Germany
- Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), Heidelberg, Germany
| | - Jens Frahm
- Biomedical NMR, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Dirk Klee
- Department of Diagnostic and Interventional Radiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Frank Pillekamp
- Department of Diagnostic and Interventional Radiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Moorenstr. 5, 40225, Düsseldorf, Germany.
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Medical Faculty and University Hospital, Heinrich-Heine-University, Düsseldorf, Germany.
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Radke KL, Grotheer V, Kamp B, Müller-Lutz A, Kertscher J, Strunk R, Martirosian P, Valentin B, Wittsack HJ, Sager M, Windolf J, Antoch G, Schiffner E, Jungbluth P, Frenken M. Comparison of compositional MRI techniques to quantify the regenerative potential of articular cartilage: a preclinical minipig model after osteochondral defect treatments with autologous mesenchymal stromal cells and unseeded scaffolds. Quant Imaging Med Surg 2023; 13:7467-7483. [PMID: 37969627 PMCID: PMC10644139 DOI: 10.21037/qims-23-570] [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: 04/28/2023] [Accepted: 08/28/2023] [Indexed: 11/17/2023]
Abstract
Background The field of orthopedics seeks effective, safer methods for evaluating articular cartilage regeneration. Despite various treatment innovations, non-invasive, contrast-free full quantitative assessments of hyaline articular cartilage's regenerative potential using compositional magnetic resonance (MR) sequences remain challenging. In this context, our aim was to investigate the effectiveness of different MR sequences for quantitative assessment of cartilage and to compare them with the current gold standard delayed gadolinium-enhanced MR imaging of cartilage (dGEMRIC) measurements. Methods We employed ex vivo imaging in a preclinical minipig model to assess knee cartilage regeneration. Standardized osteochondral defects were drilled in the proximal femur of the specimens (n=14), which were divided into four groups. Porcine collagen scaffolds seeded with autologous adipose-derived stromal cells (ASC), autologous bone marrow stromal cells (BMSC), and unseeded scaffolds (US) were implanted in femoral defects. Furthermore, there was a defect group which received no treatment. After 6 months, the specimens were examined using different compositional MR methods, including the gold standard dGEMRIC as well as T1, T2, T2*, and T1ρ techniques. The statistical evaluation involved comparing the defect region with the uninjured tibia and femur cartilage layers and all measurements were performed on a clinical 3T MR Scanner. Results In the untreated defect group, we observed significant differences in the defect region, with dGEMRIC values significantly lower (404.86±64.2 ms, P=0.018) and T2 times significantly higher (44.24±2.75 ms, P<0.001). Contrastingly, in all three treatment groups (ASC, BMSC, US), there were no significant differences among the three regions in the dGEMRIC sequence, suggesting successful cartilage regeneration. However, T1, T2*, and T1ρ sequences failed to detect such differences, highlighting their lower sensitivity for cartilage regeneration. Conclusions As expected, dGEMRIC is well suited for monitoring cartilage regeneration. Interestingly, T2 imaging also proved to be a reliable cartilage imaging technique and thus offers a contrast agent-free alternative to the former gold standard for subsequent in vivo studies investigating the cartilage regeneration potential of different treatment modalities.
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Affiliation(s)
- Karl Ludger Radke
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Vera Grotheer
- Department of Orthopedics and Trauma Surgery, Heinrich Heine University Hospital Düsseldorf, Düsseldorf, Germany
| | - Benedikt Kamp
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Anja Müller-Lutz
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Justus Kertscher
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Rosanna Strunk
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Petros Martirosian
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University Hospital Tübingen, Tübingen, Germany
| | - Birte Valentin
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Hans-Jörg Wittsack
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Martin Sager
- Central Unit for Animal Research and Animal Welfare Affairs, University Hospital, Heinrich Heine University, Düsseldorf, Germany
| | - Joachim Windolf
- Department of Orthopedics and Trauma Surgery, Heinrich Heine University Hospital Düsseldorf, Düsseldorf, Germany
| | - Gerald Antoch
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Erik Schiffner
- Department of Orthopedics and Trauma Surgery, Heinrich Heine University Hospital Düsseldorf, Düsseldorf, Germany
| | - Pascal Jungbluth
- Department of Orthopedics and Trauma Surgery, Heinrich Heine University Hospital Düsseldorf, Düsseldorf, Germany
| | - Miriam Frenken
- Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University Hospital Düsseldorf, Düsseldorf, Germany
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Radke KL, Kamp B, Adriaenssens V, Stabinska J, Gallinnis P, Wittsack HJ, Antoch G, Müller-Lutz A. Deep Learning-Based Denoising of CEST MR Data: A Feasibility Study on Applying Synthetic Phantoms in Medical Imaging. Diagnostics (Basel) 2023; 13:3326. [PMID: 37958222 PMCID: PMC10650582 DOI: 10.3390/diagnostics13213326] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/18/2023] [Accepted: 10/25/2023] [Indexed: 11/15/2023] Open
Abstract
Chemical Exchange Saturation Transfer (CEST) magnetic resonance imaging (MRI) provides a novel method for analyzing biomolecule concentrations in tissues without exogenous contrast agents. Despite its potential, achieving a high signal-to-noise ratio (SNR) is imperative for detecting small CEST effects. Traditional metrics such as Magnetization Transfer Ratio Asymmetry (MTRasym) and Lorentzian analyses are vulnerable to image noise, hampering their precision in quantitative concentration estimations. Recent noise-reduction algorithms like principal component analysis (PCA), nonlocal mean filtering (NLM), and block matching combined with 3D filtering (BM3D) have shown promise, as there is a burgeoning interest in the utilization of neural networks (NNs), particularly autoencoders, for imaging denoising. This study uses the Bloch-McConnell equations, which allow for the synthetic generation of CEST images and explores NNs efficacy in denoising these images. Using synthetically generated phantoms, autoencoders were created, and their performance was compared with traditional denoising methods using various datasets. The results underscored the superior performance of NNs, notably the ResUNet architectures, in noise identification and abatement compared to analytical approaches across a wide noise gamut. This superiority was particularly pronounced at elevated noise intensities in the in vitro data. Notably, the neural architectures significantly improved the PSNR values, achieving up to 35.0, while some traditional methods struggled, especially in low-noise reduction scenarios. However, the application to the in vivo data presented challenges due to varying noise profiles. This study accentuates the potential of NNs as robust denoising tools, but their translation to clinical settings warrants further investigation.
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Affiliation(s)
- Karl Ludger Radke
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, 40225 Dusseldorf, Germany (G.A.); (A.M.-L.)
| | - Benedikt Kamp
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, 40225 Dusseldorf, Germany (G.A.); (A.M.-L.)
| | - Vibhu Adriaenssens
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, 40225 Dusseldorf, Germany (G.A.); (A.M.-L.)
| | - Julia Stabinska
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
- Division of MR Research, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Patrik Gallinnis
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, 40225 Dusseldorf, Germany (G.A.); (A.M.-L.)
| | - Hans-Jörg Wittsack
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, 40225 Dusseldorf, Germany (G.A.); (A.M.-L.)
| | - Gerald Antoch
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, 40225 Dusseldorf, Germany (G.A.); (A.M.-L.)
| | - Anja Müller-Lutz
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, 40225 Dusseldorf, Germany (G.A.); (A.M.-L.)
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Frenken M, Radke KL, Schäfer ELE, Valentin B, Wilms LM, Abrar DB, Nebelung S, Martirosian P, Wittsack HJ, Müller-Lutz A. Insights into the Age Dependency of Compositional MR Biomarkers Quantifying the Health Status of Cartilage in Metacarpophalangeal Joints. Diagnostics (Basel) 2023; 13:diagnostics13101746. [PMID: 37238230 DOI: 10.3390/diagnostics13101746] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/10/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
(1) Background: We aim to investigate age-related changes in cartilage structure and composition in the metacarpophalangeal (MCP) joints using magnetic resonance (MR) biomarkers. (2) Methods: The cartilage tissue of 90 MCP joints from 30 volunteers without any signs of destruction or inflammation was examined using T1, T2, and T1ρ compositional MR imaging techniques on a 3 Tesla clinical scanner and correlated with age. (3) Results: The T1ρ and T2 relaxation times showed a significant correlation with age (T1ρ: Kendall-τ-b = 0.3, p < 0.001; T2: Kendall-τ-b = 0.2, p = 0.01). No significant correlation was observed for T1 as a function of age (T1: Kendall-τ-b = 0.12, p = 0.13). (4) Conclusions: Our data show an increase in T1ρ and T2 relaxation times with age. We hypothesize that this increase is due to age-related changes in cartilage structure and composition. In future examinations of cartilage using compositional MRI, especially T1ρ and T2 techniques, e.g., in patients with osteoarthritis or rheumatoid arthritis, the age of the patients should be taken into account.
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Affiliation(s)
- Miriam Frenken
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany
| | - Karl Ludger Radke
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany
| | - Emilia Louisa Ernestine Schäfer
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany
| | - Birte Valentin
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany
| | - Lena Marie Wilms
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany
- Department of Orthopedics and Trauma Surgery, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany
| | - Daniel Benjamin Abrar
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany
| | - Sven Nebelung
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany
- Department of Diagnostic and Interventional Radiology, University Hospital Aachen, D-52074 Aachen, Germany
| | - Petros Martirosian
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Tübingen, D-72076 Tübingen, Germany
| | - Hans-Jörg Wittsack
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany
| | - Anja Müller-Lutz
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany
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8
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Wittsack HJ, Radke KL, Stabinska J, Ljimani A, Müller-Lutz A. calf - Software for CEST Analysis with Lorentzian Fitting. J Med Syst 2023; 47:39. [PMID: 36961580 PMCID: PMC10038975 DOI: 10.1007/s10916-023-01931-6] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 02/27/2023] [Indexed: 03/25/2023]
Abstract
Analysis of chemical exchange saturation transfer (CEST) MRI data requires sophisticated methods to obtain reliable results about metabolites in the tissue under study. CEST generates z-spectra with multiple components, each originating from individual molecular groups. The individual lines with Lorentzian line shape are mostly overlapping and disturbed by various effects. We present an elaborate method based on an adaptive nonlinear least squares algorithm that provides robust quantification of z-spectra and incorporates prior knowledge in the fitting process. To disseminate CEST to the research community, we developed software as part of this study that runs on the Microsoft Windows operating system and will be made freely available to the community. Special attention has been paid to establish a low entrance threshold and high usability, so that even less experienced users can successfully analyze CEST data.
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Affiliation(s)
- Hans-Jörg Wittsack
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, D-40225, Dusseldorf, Germany.
| | - Karl Ludger Radke
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, D-40225, Dusseldorf, Germany
| | - Julia Stabinska
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, 21205, USA
- Division of MR Research, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Alexandra Ljimani
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, D-40225, Dusseldorf, Germany
| | - Anja Müller-Lutz
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, D-40225, Dusseldorf, Germany
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9
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Boschheidgen M, Al-Monajjed R, Minko P, Jannusch K, Ullrich T, Radke KL, Michalski R, Radtke JP, Albers P, Antoch G, Schimmöller L. Influence of benign prostatic hyperplasia patterns detected with MRI on the clinical outcome after prostatic artery embolization. CVIR Endovasc 2023; 6:9. [PMID: 36859572 PMCID: PMC9978045 DOI: 10.1186/s42155-023-00357-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 02/14/2023] [Indexed: 03/03/2023] Open
Abstract
BACKGROUND To investigate the influence of benign prostatic hyperplasia (BPH) patterns detected with MRI on clinical outcomes after prostatic artery embolization (PAE). MATERIALS & METHODS This retrospective study included 71 consecutive patients with lower urinary tract symptoms (LUTS), who underwent magnetic resonance imaging (MRI) of the prostate followed by PAE at a single centre. MRI scans were evaluated and BPH patterns were determined according to Wasserman type and a modified BPH classification. Additionally, scans were evaluated regarding the presence of adenomatous-dominant benign prostatic hyperplasia (AdBPH). LUTS were assessed using the International Prostate Symptom Score (IPSS) and urinary flow rate (Qmax). Follow-up examination included MRI and clinical outcome. RESULTS For clinical outcome at follow-up, IPSS showed median reduction of 54% (IQR 41-75%) and Qmax improved by 4.1 ml/s. We noted significant reduction in volume, intraprostatic protrusion, and prostatic urethral angle in our collective (p < 0.01). Median volume reduction was 25% (IQR 15%-34%). Bilateral embolization was a significant predictor for volume reduction at follow-up. Multiple linear regression analysis showed significant effect of high initial volume on reduction in IPSS after treatment (p < 0.01). Presence of AdBPH was significantly associated with both, volume loss and clinical improvement in terms of IPSS reduction (p < 0.01). Neither BPH pattern based on the Wassermann type nor modified BPH classification were significantly related with postinterventional IPSS and volume loss. CONCLUSIONS Men benefit from PAE regardless the macroscopic BPH MRI pattern. Preinterventional prostate volume and presence of AdBPH on MRI should be considered for outcome prognosis after PAE.
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Affiliation(s)
- Matthias Boschheidgen
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Moorenstr. 5, Dusseldorf, D-40225, Germany.
| | - Rouvier Al-Monajjed
- grid.411327.20000 0001 2176 9917Medical Faculty, Department of Urology, University Dusseldorf, Moorenstr. 5, Dusseldorf, D-40225 Germany
| | - Peter Minko
- grid.411327.20000 0001 2176 9917Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Moorenstr. 5, Dusseldorf, D-40225 Germany
| | - Kai Jannusch
- grid.411327.20000 0001 2176 9917Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Moorenstr. 5, Dusseldorf, D-40225 Germany
| | - Tim Ullrich
- grid.411327.20000 0001 2176 9917Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Moorenstr. 5, Dusseldorf, D-40225 Germany
| | - Karl Ludger Radke
- grid.411327.20000 0001 2176 9917Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Moorenstr. 5, Dusseldorf, D-40225 Germany
| | - Rene Michalski
- grid.411327.20000 0001 2176 9917Medical Faculty, Department of Urology, University Dusseldorf, Moorenstr. 5, Dusseldorf, D-40225 Germany
| | - Jan Philipp Radtke
- grid.411327.20000 0001 2176 9917Medical Faculty, Department of Urology, University Dusseldorf, Moorenstr. 5, Dusseldorf, D-40225 Germany
| | - Peter Albers
- grid.411327.20000 0001 2176 9917Medical Faculty, Department of Urology, University Dusseldorf, Moorenstr. 5, Dusseldorf, D-40225 Germany
| | - Gerald Antoch
- grid.411327.20000 0001 2176 9917Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Moorenstr. 5, Dusseldorf, D-40225 Germany
| | - Lars Schimmöller
- grid.411327.20000 0001 2176 9917Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Moorenstr. 5, Dusseldorf, D-40225 Germany
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10
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Wilms LM, Radke KL, Latz D, Thiel TA, Frenken M, Kamp B, Filler TJ, Nagel AM, Müller-Lutz A, Abrar DB, Nebelung S. UTE-T2* versus conventional T2* mapping to assess posterior cruciate ligament ultrastructure and integrity-an in-situ study. Quant Imaging Med Surg 2022; 12:4190-4201. [PMID: 35919061 PMCID: PMC9338370 DOI: 10.21037/qims-22-251] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [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: 03/17/2022] [Accepted: 05/23/2022] [Indexed: 01/01/2023]
Abstract
Background Clinical-standard morphologic magnetic resonance imaging (MRI) is limited in the refined diagnosis of posterior cruciate ligament (PCL) injuries. Quantitative MRI sequences such as ultrashort echo-time (UTE)-T2* mapping or conventional T2* mapping have been theorized to quantify ligament (ultra-) structure and integrity beyond morphology. This study evaluates their diagnostic potential in identifying and differentiating partial and complete PCL injuries in a standardized graded injury model. Methods Ten human cadaveric knee joint specimens were imaged on a clinical 3.0 T MRI scanner using morphologic, conventional T2* mapping, and UTE-T2* mapping sequences before and after standardized arthroscopic partial and complete PCL transection. Following manual segmentation, quantitative T2* and underlying texture features (i.e., energy, homogeneity, and variance) were analyzed for each specimen and PCL condition, both for the entire PCL and its subregions. For statistical analysis, Friedman’s test followed by Dunn’s multiple comparison test was used against the level of significance of P≤0.01. Results For the entire PCL, T2* was significantly increased as a function of injury when acquired with the UTE-T2* sequence [entire PCL: 11.1±3.1 ms (intact); 10.9±4.6 ms (partial); 14.3±4.9 ms (complete); P<0.001], but not when acquired with the conventional T2* sequence [entire PCL: 10.0±3.2 ms (intact); 11.4±6.2 ms (partial); 15.5±7.8 ms (complete); P=0.046]. The PCL subregions and texture variables showed variable changes indicative of injury-associated disorganization. Conclusions In contrast to the conventional T2* mapping, UTE-T2* mapping is more receptive in the detection of structural damage of the PCL and allows quantitative assessment of ligament (ultra-)structure and integrity that may help to improve diagnostic differentiation of distinct injury states. Once further substantiated beyond the in-situ setting, UTE-T2* mapping may refine diagnostic evaluation of PCL injuries and -possibly- monitor ligament healing, ageing, degeneration, and inflammation.
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Affiliation(s)
- Lena Marie Wilms
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Dusseldorf, Germany.,Department of Orthopaedics and Trauma Surgery, Medical Faculty, University Dusseldorf, Dusseldorf, Germany
| | - Karl Ludger Radke
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Dusseldorf, Germany
| | - David Latz
- Department of Orthopaedics and Trauma Surgery, Medical Faculty, University Dusseldorf, Dusseldorf, Germany
| | - Thomas Andreas Thiel
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Dusseldorf, Germany
| | - Miriam Frenken
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Dusseldorf, Germany
| | - Benedikt Kamp
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Dusseldorf, Germany
| | | | - Armin Michael Nagel
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.,Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Anja Müller-Lutz
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Dusseldorf, Germany
| | - Daniel Benjamin Abrar
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Dusseldorf, Germany
| | - Sven Nebelung
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Dusseldorf, Germany.,Department of Diagnostic and Interventional Radiology, University Hospital Aachen, Aachen, Germany
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11
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Frenken M, Rübsam G, Mewes A, Radke KL, Li L, Wilms LM, Nebelung S, Abrar DB, Sewerin P. To Contrast or Not to Contrast? On the Role of Contrast Enhancement in Hand MRI Studies of Patients with Rheumatoid Arthritis. Diagnostics (Basel) 2022; 12:diagnostics12020465. [PMID: 35204555 PMCID: PMC8871222 DOI: 10.3390/diagnostics12020465] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/01/2022] [Accepted: 02/09/2022] [Indexed: 12/10/2022] Open
Abstract
Currently, clinical indications for the application of gadolinium-based contrast agents (GBCA) in magnetic resonance imaging (MRI) are increasingly being questioned. Consequently, this study aimed to evaluate the additional diagnostic value of contrast enhancement in MRI of the hand in patients with rheumatoid arthritis (RA). Thirty-one patients with RA (mean age, 50 ± 14 years (range, 18–72 years)) underwent morphologic MRI scans on a clinical 3 T scanner. MRI studies were analyzed based on (1) the Rheumatoid Arthritis Magnetic Resonance Imaging Score (RAMRIS) and (2) the GBCA-free RAMRIS version, termed RAMRIS Sine-Gadolinium-For-Experts (RAMRIS-SAFE), in which synovitis and tenosynovitis were assessed using the short-tau inversion-recovery sequence instead of the post-contrast T1-weighted sequence. The synovitis subscores in terms of Spearman’s ρ, as based on RAMRIS and RAMRIS-SAFE, were almost perfect (ρ = 0.937; p < 0.001), while the tenosynovitis subscores were less strongly correlated (ρ = 0.380 p = 0.035). Correlation between the total RAMRIS and RAMRIS-SAFE was also almost perfect (ρ = 0.976; p < 0.001). Inter-rater reliability in terms of Cohen’s κ was high (0.963 ≤ κ ≤ 0.925). In conclusion, RAMRIS-SAFE as the GBCA-free version of the well-established RAMRIS is a patient-friendly and resource-efficient alternative for assessing disease-related joint changes in RA. As patients with RA are subject to repetitive GBCA applications, non-contrast imaging protocols should be considered.
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Affiliation(s)
- Miriam Frenken
- Institute of Diagnostic and Interventional Radiology, University Hospital of Düsseldorf, Moorenstraße 5, 40225 Dusseldorf, Germany; (A.M.); (K.L.R.); (L.M.W.); (S.N.); (D.B.A.)
- Correspondence:
| | - Gesa Rübsam
- Department and Hiller Research Unit of Rheumatology, Heinrich Heine University Düsseldorf, UKD, Moorenstrasse 5, 40225 Düsseldorf, Germany; (G.R.); (P.S.)
| | - Alexander Mewes
- Institute of Diagnostic and Interventional Radiology, University Hospital of Düsseldorf, Moorenstraße 5, 40225 Dusseldorf, Germany; (A.M.); (K.L.R.); (L.M.W.); (S.N.); (D.B.A.)
| | - Karl Ludger Radke
- Institute of Diagnostic and Interventional Radiology, University Hospital of Düsseldorf, Moorenstraße 5, 40225 Dusseldorf, Germany; (A.M.); (K.L.R.); (L.M.W.); (S.N.); (D.B.A.)
| | - Lien Li
- Institute for Medical Information Processing, Biometry and Epidemiology, Ludwig-Maximilians-Universität München, Marchioninistr. 15, 81377 Munich, Germany;
| | - Lena M. Wilms
- Institute of Diagnostic and Interventional Radiology, University Hospital of Düsseldorf, Moorenstraße 5, 40225 Dusseldorf, Germany; (A.M.); (K.L.R.); (L.M.W.); (S.N.); (D.B.A.)
| | - Sven Nebelung
- Institute of Diagnostic and Interventional Radiology, University Hospital of Düsseldorf, Moorenstraße 5, 40225 Dusseldorf, Germany; (A.M.); (K.L.R.); (L.M.W.); (S.N.); (D.B.A.)
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, 52074 Aachen, Germany
| | - Daniel B. Abrar
- Institute of Diagnostic and Interventional Radiology, University Hospital of Düsseldorf, Moorenstraße 5, 40225 Dusseldorf, Germany; (A.M.); (K.L.R.); (L.M.W.); (S.N.); (D.B.A.)
| | - Philipp Sewerin
- Department and Hiller Research Unit of Rheumatology, Heinrich Heine University Düsseldorf, UKD, Moorenstrasse 5, 40225 Düsseldorf, Germany; (G.R.); (P.S.)
- Rheumazentrum Ruhrgebiet Herne, Ruhr-University Bochum, 44649 Herne, Germany
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12
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Röwer LM, Radke KL, Hußmann J, Malik H, Uelwer T, Voit D, Frahm J, Wittsack HJ, Harmeling S, Pillekamp F, Klee D. Comparison of cardiac volumetry using real-time MRI during free-breathing with standard cine MRI during breath-hold in children. Pediatr Radiol 2022; 52:1462-1475. [PMID: 35353211 PMCID: PMC9271116 DOI: 10.1007/s00247-022-05327-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/13/2022] [Accepted: 02/16/2022] [Indexed: 01/18/2023]
Abstract
BACKGROUND Cardiac real-time magnetic resonance imaging (RT-MRI) provides high-quality images even during free-breathing. Difficulties in post-processing impede its use in clinical routine. OBJECTIVE To demonstrate the feasibility of quantitative analysis of cardiac free-breathing RT-MRI and to compare image quality and volumetry during free-breathing RT-MRI in pediatric patients to standard breath-hold cine MRI. MATERIALS AND METHODS Pediatric patients (n = 22) received cardiac RT-MRI volumetry during free breathing (1.5 T; short axis; 30 frames per s) in addition to standard breath-hold cine imaging in end-expiration. Real-time images were binned retrospectively based on electrocardiography and respiratory bellows. Image quality and volumetry were compared using the European Cardiovascular Magnetic Resonance registry score, structure visibility rating, linear regression and Bland-Altman analyses. RESULTS Additional time for binning of real-time images was 2 min. For both techniques, image quality was rated good to excellent. RT-MRI was significantly more robust against artifacts (P < 0.01). Linear regression revealed good correlations for the ventricular volumes. Bland-Altman plots showed a good limit of agreement (LoA) for end-diastolic volume (left ventricle [LV]: LoA -0.1 ± 2.7 ml/m2, right ventricle [RV]: LoA -1.9 ± 3.4 ml/m2), end-systolic volume (LV: LoA 0.4 ± 1.9 ml/m2, RV: LoA 0.6 ± 2.0 ml/m2), stroke volume (LV: LoA -0.5 ± 2.3 ml/m2, RV: LoA -2.6 ± 3.3 ml/m2) and ejection fraction (LV: LoA -0.5 ± 1.6%, RV: LoA -2.1 ± 2.8%). CONCLUSION Compared to standard cine MRI with breath hold, RT-MRI during free breathing with retrospective respiratory binning offers good image quality, reduced image artifacts enabling fast quantitative evaluations of ventricular volumes in clinical practice under physiological conditions.
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Affiliation(s)
- Lena Maria Röwer
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Moorenstr. 5, 40225, Dusseldorf, Germany.
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich Heine University, Dusseldorf, Germany.
| | - Karl Ludger Radke
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich Heine University, Dusseldorf, Germany
| | - Janina Hußmann
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Moorenstr. 5, 40225, Dusseldorf, Germany
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich Heine University, Dusseldorf, Germany
| | - Halima Malik
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Moorenstr. 5, 40225, Dusseldorf, Germany
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich Heine University, Dusseldorf, Germany
| | - Tobias Uelwer
- Department of Computer Science, Heinrich Heine University, Dusseldorf, Germany
| | - Dirk Voit
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Göttingen, Germany
| | - Hans-Joerg Wittsack
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich Heine University, Dusseldorf, Germany
| | - Stefan Harmeling
- Department of Computer Science, Heinrich Heine University, Dusseldorf, Germany
| | - Frank Pillekamp
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Moorenstr. 5, 40225, Dusseldorf, Germany
| | - Dirk Klee
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich Heine University, Dusseldorf, Germany
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13
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Boschheidgen M, Schimmöller L, Arsov C, Ziayee F, Morawitz J, Valentin B, Radke KL, Giessing M, Esposito I, Albers P, Antoch G, Ullrich T. MRI grading for the prediction of prostate cancer aggressiveness. Eur Radiol 2021; 32:2351-2359. [PMID: 34748064 PMCID: PMC8921105 DOI: 10.1007/s00330-021-08332-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [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: 04/06/2021] [Revised: 08/15/2021] [Accepted: 09/06/2021] [Indexed: 01/01/2023]
Abstract
OBJECTIVES T o evaluate the value of multiparametric MRI (mpMRI) for the prediction of prostate cancer (PCA) aggressiveness. METHODS In this single center cohort study, consecutive patients with histologically confirmed PCA were retrospectively enrolled. Four different ISUP grade groups (1, 2, 3, 4-5) were defined and fifty patients per group were included. Several clinical (age, PSA, PSAD, percentage of PCA infiltration) and mpMRI parameters (ADC value, signal increase on high b-value images, diameter, extraprostatic extension [EPE], cross-zonal growth) were evaluated and correlated within the four groups. Based on combined descriptors, MRI grading groups (mG1-mG3) were defined to predict PCA aggressiveness. RESULTS In total, 200 patients (mean age 68 years, median PSA value 8.1 ng/ml) were analyzed. Between the four groups, statistically significant differences could be shown for age, PSA, PSAD, and for MRI parameters cross-zonal growth, high b-value signal increase, EPE, and ADC (p < 0.01). All examined parameters revealed a significant correlation with the histopathologic biopsy ISUP grade groups (p < 0.01), except PCA diameter (p = 0.09). A mixed linear model demonstrated the strongest prediction of the respective ISUP grade group for the MRI grading system (p < 0.01) compared to single parameters. CONCLUSIONS MpMRI yields relevant pre-biopsy information about PCA aggressiveness. A combination of quantitative and qualitative parameters (MRI grading groups) provided the best prediction of the biopsy ISUP grade group and may improve clinical pathway and treatment planning, adding useful information beyond PI-RADS assessment category. Due to the high prevalence of higher grade PCA in patients within mG3, an early re-biopsy seems indicated in cases of negative or post-biopsy low-grade PCA. KEY POINTS • MpMRI yields relevant pre-biopsy information about prostate cancer aggressiveness. • MRI grading in addition to PI-RADS classification seems to be helpful for a size independent early prediction of clinically significant PCA. • MRI grading groups may help urologists in clinical pathway and treatment planning, especially when to consider an early re-biopsy.
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Affiliation(s)
- M Boschheidgen
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - L Schimmöller
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany.
| | - C Arsov
- Department of Urology, Medical Faculty, University Dusseldorf, 40225, Düsseldorf, Germany
| | - F Ziayee
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - J Morawitz
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - B Valentin
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - K L Radke
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - M Giessing
- Department of Urology, Medical Faculty, University Dusseldorf, 40225, Düsseldorf, Germany
| | - I Esposito
- Department of Pathology, Medical Faculty, University Dusseldorf, 40225, Düsseldorf, Germany
| | - P Albers
- Department of Urology, Medical Faculty, University Dusseldorf, 40225, Düsseldorf, Germany
| | - G Antoch
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - T Ullrich
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
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14
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Wollschläger LM, Radke KL, Schock J, Kotowski N, Latz D, Kanschik D, Filler TJ, Caspers S, Antoch G, Windolf J, Abrar DB, Nebelung S. The MRI posterior drawer test to assess posterior cruciate ligament functionality and knee joint laxity. Sci Rep 2021; 11:19687. [PMID: 34608233 PMCID: PMC8490383 DOI: 10.1038/s41598-021-99216-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 04/14/2021] [Accepted: 09/15/2021] [Indexed: 11/23/2022] Open
Abstract
Clinical Magnetic Resonance Imaging (MRI) of joints is limited to mere morphologic evaluation and fails to directly visualize joint or ligament function. In this controlled laboratory study, we show that knee joint functionality may be quantified in situ and as a function of graded posterior cruciate ligament (PCL)-deficiency by combining MRI and standardized loading. 11 human knee joints underwent MRI under standardized posterior loading in the unloaded and loaded (147 N) configurations and in the intact, partially, and completely PCL-injured conditions. For each specimen, configuration, and condition, 3D joint models were implemented to analyse joint kinematics based on 3D Euclidean vectors and their projections on the Cartesian planes. Manual 2D measurements served as reference. With increasing PCL deficiency, vector projections increased significantly in the anteroposterior dimension under loading and manual measurements demonstrated similar patterns of change. Consequently, if combined with advanced image post-processing, stress MRI is a powerful diagnostic adjunct to evaluate ligament functionality and joint laxity in multiple dimensions and may have a role in differentiating PCL injury patterns, therapeutic decision-making, and treatment monitoring.
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Affiliation(s)
- Lena Marie Wollschläger
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40225, Düsseldorf, Germany.,Department of Orthopaedics and Trauma Surgery, Medical Faculty, University Dusseldorf, 40225, Düsseldorf, Germany
| | - Karl Ludger Radke
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40225, Düsseldorf, Germany
| | - Justus Schock
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40225, Düsseldorf, Germany
| | - Niklas Kotowski
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany
| | - David Latz
- Department of Orthopaedics and Trauma Surgery, Medical Faculty, University Dusseldorf, 40225, Düsseldorf, Germany
| | - Dominika Kanschik
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40225, Düsseldorf, Germany
| | - Timm Joachim Filler
- Institute of Anatomy I, Heinrich-Heine-University, 40225, Düsseldorf, Germany
| | - Svenja Caspers
- Institute of Anatomy I, Heinrich-Heine-University, 40225, Düsseldorf, Germany
| | - Gerald Antoch
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40225, Düsseldorf, Germany
| | - Joachim Windolf
- Department of Orthopaedics and Trauma Surgery, Medical Faculty, University Dusseldorf, 40225, Düsseldorf, Germany
| | - Daniel Benjamin Abrar
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40225, Düsseldorf, Germany
| | - Sven Nebelung
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstraße 5, 40225, Düsseldorf, Germany.
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15
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Wilms LM, Radke KL, Abrar DB, Latz D, Schock J, Frenken M, Windolf J, Antoch G, Filler TJ, Nebelung S. Micro- and Macroscale Assessment of Posterior Cruciate Ligament Functionality Based on Advanced MRI Techniques. Diagnostics (Basel) 2021; 11:1790. [PMID: 34679487 PMCID: PMC8535058 DOI: 10.3390/diagnostics11101790] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/20/2021] [Accepted: 09/24/2021] [Indexed: 12/18/2022] Open
Abstract
T2 mapping assesses tissue ultrastructure and composition, yet the association of imaging features and tissue functionality is oftentimes unclear. This study aimed to elucidate this association for the posterior cruciate ligament (PCL) across the micro- and macroscale and as a function of loading. Ten human cadaveric knee joints were imaged using a clinical 3.0T scanner and high-resolution morphologic and T2 mapping sequences. Emulating the posterior drawer test, the joints were imaged in the unloaded (δ0) and loaded (δ1) configurations. For the entire PCL, its subregions, and its osseous insertion sites, loading-induced changes were parameterized as summary statistics and texture variables, i.e., entropy, homogeneity, contrast, and variance. Histology confirmed structural integrity. Statistical analysis was based on parametric and non-parametric tests. Mean PCL length (37.8 ± 1.8 mm [δ0]; 44.0 ± 1.6 mm [δ1] [p < 0.01]), mean T2 (35.5 ± 2.0 ms [δ0]; 37.9 ± 1.3 ms [δ1] [p = 0.01]), and mean contrast values (4.0 ± 0.6 [δ0]; 4.9 ± 0.9 [δ1] [p = 0.01]) increased significantly under loading. Other texture features or ligamentous, osseous, and meniscal structures remained unaltered. Beyond providing normative T2 values across various scales and configurations, this study suggests that ligaments can be imaged morphologically and functionally based on joint loading and advanced MRI acquisition and post-processing techniques to assess ligament integrity and functionality in variable diagnostic contexts.
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Affiliation(s)
- Lena Marie Wilms
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany; (K.L.R.); (D.B.A.); (J.S.); (M.F.); (G.A.); (S.N.)
- Department of Orthopedics and Trauma Surgery, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany; (D.L.); (J.W.)
| | - Karl Ludger Radke
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany; (K.L.R.); (D.B.A.); (J.S.); (M.F.); (G.A.); (S.N.)
| | - Daniel Benjamin Abrar
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany; (K.L.R.); (D.B.A.); (J.S.); (M.F.); (G.A.); (S.N.)
| | - David Latz
- Department of Orthopedics and Trauma Surgery, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany; (D.L.); (J.W.)
| | - Justus Schock
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany; (K.L.R.); (D.B.A.); (J.S.); (M.F.); (G.A.); (S.N.)
| | - Miriam Frenken
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany; (K.L.R.); (D.B.A.); (J.S.); (M.F.); (G.A.); (S.N.)
| | - Joachim Windolf
- Department of Orthopedics and Trauma Surgery, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany; (D.L.); (J.W.)
| | - Gerald Antoch
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany; (K.L.R.); (D.B.A.); (J.S.); (M.F.); (G.A.); (S.N.)
| | - Timm Joachim Filler
- Institute for Anatomy I, Heinrich-Heine-University, D-40225 Dusseldorf, Germany;
| | - Sven Nebelung
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Hospital of Dusseldorf, D-40225 Dusseldorf, Germany; (K.L.R.); (D.B.A.); (J.S.); (M.F.); (G.A.); (S.N.)
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16
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Truhn D, Zwingenberger KT, Schock J, Abrar DB, Radke KL, Post M, Linka K, Knobe M, Kuhl C, Nebelung S. No pressure, no diamonds? - Static vs. dynamic compressive in-situ loading to evaluate human articular cartilage functionality by functional MRI. J Mech Behav Biomed Mater 2021; 120:104558. [PMID: 33957568 DOI: 10.1016/j.jmbbm.2021.104558] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 03/22/2021] [Accepted: 04/19/2021] [Indexed: 01/21/2023]
Abstract
Biomechanical Magnetic Resonance Imaging (MRI) of articular cartilage, i.e. its imaging under loading, is a promising diagnostic tool to assess the tissue's functionality in health and disease. This study aimed to assess the response to static and dynamic loading of histologically intact cartilage samples by functional MRI and pressure-controlled in-situ loading. To this end, 47 cartilage samples were obtained from the medial femoral condyles of total knee arthroplasties (from 24 patients), prepared to standard thickness, and placed in a standard knee joint in a pressure-controlled whole knee-joint compressive loading device. Cartilage samples' responses to static (i.e. constant), dynamic (i.e. alternating), and no loading, i.e. free-swelling conditions, were assessed before (δ0), and after 30 min (δ1) and 60 min (δ2) of loading using serial T1ρ maps acquired on a 3.0T clinical MRI scanner (Achieva, Philips). Alongside texture features, relative changes in T1ρ (Δ1, Δ2) were determined for the upper and lower sample halves and the entire sample, analyzed using appropriate statistical tests, and referenced to histological (Mankin scoring) and biomechanical reference measures (tangent stiffness). Histological, biomechanical, and T1ρ sample characteristics at δ0 were relatively homogenous in all samples. In response to loading, relative increases in T1ρ were strong and significant after dynamic loading (Δ1 = 10.3 ± 17.0%, Δ2 = 21.6 ± 21.8%, p = 0.002), while relative increases in T1ρ after static loading and in controls were moderate and not significant. Generally, texture features did not demonstrate clear loading-related associations underlying the spatial relationships of T1ρ. When realizing the clinical translation, this in-situ study suggests that serial T1ρ mapping is best combined with dynamic loading to assess cartilage functionality in humans based on advanced MRI techniques.
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Affiliation(s)
- Daniel Truhn
- Aachen University Hospital, Department of Diagnostic and Interventional Radiology, D-52074, Aachen, Germany
| | - Ken Tonio Zwingenberger
- Aachen University Hospital, Department of Diagnostic and Interventional Radiology, D-52074, Aachen, Germany
| | - Justus Schock
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225, Düsseldorf, Germany; Institute of Imaging and Computer Vision, RWTH Aachen University, D-52074, Aachen, Germany
| | - Daniel Benjamin Abrar
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225, Düsseldorf, Germany
| | - Karl Ludger Radke
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225, Düsseldorf, Germany
| | - Manuel Post
- Aachen University Hospital, Department of Diagnostic and Interventional Radiology, D-52074, Aachen, Germany
| | - Kevin Linka
- Hamburg University of Technology, Department of Continuum and Materials Mechanics, D-21073, Hamburg, Germany
| | - Matthias Knobe
- Cantonal Hospital Lucerne, Department of Orthopaedic and Trauma Surgery, CH-6000, Lucerne, Switzerland
| | - Christiane Kuhl
- Aachen University Hospital, Department of Diagnostic and Interventional Radiology, D-52074, Aachen, Germany
| | - Sven Nebelung
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225, Düsseldorf, Germany.
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Huppertz MS, Schock J, Radke KL, Abrar DB, Post M, Kuhl C, Truhn D, Nebelung S. Longitudinal T2 Mapping and Texture Feature Analysis in the Detection and Monitoring of Experimental Post-Traumatic Cartilage Degeneration. Life (Basel) 2021; 11:life11030201. [PMID: 33807740 PMCID: PMC8000874 DOI: 10.3390/life11030201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 01/30/2021] [Revised: 03/01/2021] [Accepted: 03/03/2021] [Indexed: 11/25/2022] Open
Abstract
Background: Traumatic cartilage injuries predispose articulating joints to focal cartilage defects and, eventually, posttraumatic osteoarthritis. Current clinical-standard imaging modalities such as morphologic MRI fail to reliably detect cartilage trauma and to monitor associated posttraumatic degenerative changes with oftentimes severe prognostic implications. Quantitative MRI techniques such as T2 mapping are promising in detecting and monitoring such changes yet lack sufficient validation in controlled basic research contexts. Material and Methods: 35 macroscopically intact cartilage samples obtained from total joint replacements were exposed to standardized injurious impaction with low (0.49 J, n = 14) or high (0.98 J, n = 14) energy levels and imaged before and immediately, 24 h, and 72 h after impaction by T2 mapping. Contrast, homogeneity, energy, and variance were quantified as features of texture on each T2 map. Unimpacted controls (n = 7) and histologic assessment served as reference. Results: As a function of impaction energy and time, absolute T2 values, contrast, and variance were significantly increased, while homogeneity and energy were significantly decreased. Conclusion: T2 mapping and texture feature analysis are sensitive diagnostic means to detect and monitor traumatic impaction injuries of cartilage and associated posttraumatic degenerative changes and may be used to assess cartilage after trauma to identify “cartilage at risk”.
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Affiliation(s)
- Marc Sebastian Huppertz
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, 52074 Aachen, Germany; (M.S.H.); (M.P.); (C.K.); (D.T.)
| | - Justus Schock
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, 40225 Dusseldorf, Germany; (J.S.); (K.L.R.); (D.B.A.)
| | - Karl Ludger Radke
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, 40225 Dusseldorf, Germany; (J.S.); (K.L.R.); (D.B.A.)
| | - Daniel Benjamin Abrar
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, 40225 Dusseldorf, Germany; (J.S.); (K.L.R.); (D.B.A.)
| | - Manuel Post
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, 52074 Aachen, Germany; (M.S.H.); (M.P.); (C.K.); (D.T.)
| | - Christiane Kuhl
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, 52074 Aachen, Germany; (M.S.H.); (M.P.); (C.K.); (D.T.)
| | - Daniel Truhn
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, 52074 Aachen, Germany; (M.S.H.); (M.P.); (C.K.); (D.T.)
| | - Sven Nebelung
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, 40225 Dusseldorf, Germany; (J.S.); (K.L.R.); (D.B.A.)
- Correspondence:
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Frenken M, Nebelung S, Schleich C, Müller-Lutz A, Radke KL, Kamp B, Boschheidgen M, Wollschläger L, Bittersohl B, Antoch G, Konieczny MR, Abrar DB. Non-Specific Low Back Pain and Lumbar Radiculopathy: Comparison of Morphologic and Compositional MRI as Assessed by gagCEST Imaging at 3T. Diagnostics (Basel) 2021; 11:diagnostics11030402. [PMID: 33652924 PMCID: PMC7996864 DOI: 10.3390/diagnostics11030402] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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: 01/08/2021] [Revised: 02/16/2021] [Accepted: 02/23/2021] [Indexed: 12/15/2022] Open
Abstract
Using glycosaminoglycan Chemical Exchange Saturation Transfer (gagCEST) magnetic resonance imaging (MRI), this study comparatively evaluated the GAG contents of lumbar intervertebral disks (IVDs) of patients with non-specific low back pain (nsLBP), radiculopathy, and asymptomatic volunteers to elucidate the association of clinical manifestation and compositional correlate. A total of 18 patients (mean age 57.5 ± 22.5 years) with radiculopathy, 16 age-matched patients with chronic nsLBP and 20 age-matched volunteers underwent standard morphologic and compositional gagCEST MRI on a 3T scanner. In all cohorts, GAG contents of lumbar IVDs were determined using gagCEST MRI. An assessment of morphologic IVD degeneration based on the Pfirrmann classification and T2-weighted sequences served as a reference. A linear mixed model adjusted for multiple confounders was used for statistical evaluation. IVDs of patients with nsLBP showed lower gagCEST values than those of volunteers (nsLBP: 1.3% [99% confidence intervals (CI): 1.0; 1.6] vs. volunteers: 1.9% [99% CI: 1.6; 2.2]). Yet, IVDs of patients with radiculopathy (1.8% [99% CI: 1.4; 2.1]) were not different from patients with nsLBP or volunteers. In patients with radiculopathy, IVDs directly adjacent to IVD extrusions demonstrated lower gagCEST values than distant IVDs (adjacent: 0.9% [99% CI: 0.3; 1.5], distant: 2.1% [99% CI: 1.7; 2.5]). Advanced GAG depletion in nsLBP and directly adjacent to IVD extrusions in radiculopathy indicates close interrelatedness of clinical pathology and compositional degeneration.
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Affiliation(s)
- Miriam Frenken
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
| | - Sven Nebelung
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
| | - Christoph Schleich
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
| | - Anja Müller-Lutz
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
| | - Karl Ludger Radke
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
| | - Benedikt Kamp
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
| | - Matthias Boschheidgen
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
| | - Lena Wollschläger
- Department of Orthopedic and Trauma Surgery, University Hospital of Duesseldorf, D-40225 Duesseldorf, Germany; (L.W.); (B.B.); (M.R.K.)
| | - Bernd Bittersohl
- Department of Orthopedic and Trauma Surgery, University Hospital of Duesseldorf, D-40225 Duesseldorf, Germany; (L.W.); (B.B.); (M.R.K.)
| | - Gerald Antoch
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
| | - Markus R. Konieczny
- Department of Orthopedic and Trauma Surgery, University Hospital of Duesseldorf, D-40225 Duesseldorf, Germany; (L.W.); (B.B.); (M.R.K.)
| | - Daniel B. Abrar
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
- Correspondence:
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19
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Abrar DB, Schleich C, Tsiami S, Müller-Lutz A, Radke KL, Holthausen N, Frenken M, Boschheidgen M, Antoch G, Mucke J, Sewerin P, Braun J, Nebelung S, Baraliakos X. Functional MR imaging beyond structure and inflammation-radiographic axial spondyloarthritis is associated with proteoglycan depletion of the lumbar spine. Arthritis Res Ther 2020; 22:219. [PMID: 32943084 PMCID: PMC7499866 DOI: 10.1186/s13075-020-02312-x] [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: 06/16/2020] [Accepted: 09/07/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To compare the glycosaminoglycan (GAG) content of lumbar intervertebral disks (IVDs) of patients with ankylosing spondylitis (AS) and healthy volunteers and to investigate the association of GAG depletion and disease-related clinical and imaging features. METHODS Lumbar spines of 50 AS patients (mean age 50 ± 10.5 years) and 30 age-matched volunteers were studied with 3-T magnetic resonance imaging (MRI) and conventional radiographs (CR). The MRI protocol included high-resolution morphological sequences and the compositional GAG chemical exchange saturation transfer imaging technique (gagCEST). Morphological images were analyzed by three raters for inflammatory activity, fat deposition, disk degeneration, and structural changes on CR. Clinical and serological measures included the Bath AS Disease Activity (BASDAI) and Bath AS Function (BASFI) Indices and C-reactive protein (CRP) levels. GagCEST values of both groups were compared using a linear mixed model. Kendall-Tau correlation analyses were performed. RESULTS GagCEST values were significantly lower in AS patients (2.0 ± 1.7%) vs. healthy volunteers (2.4 ± 1.8%), p = 0.001. Small, yet significant correlations were found between gagCEST values and CRP levels (τ = - 0.14, p = 0.007), BASFI (τ = - 0.18, p < 0.001) and presence of syndesmophytes (τ = - 0.17, p = 0.001). No significant correlations were found with BASDAI, inflammation, and fat deposition MRI scores. CONCLUSIONS Lumbar spines of r-AS patients undergo significant GAG depletion, independently associated with syndesmophyte formation, functional disability, and increased serological inflammation markers. Beyond establishing a pathophysiological role of the cartilage in AS, these findings suggest that gagCEST imaging may have an adjunct confirmatory role in the assessment of disease-related pathological MRI findings in axial spondyloarthritis. TRIAL REGISTRATION 3980 ( https://studienregister.med.uni-duesseldorf.de ).
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Affiliation(s)
- Daniel B Abrar
- Department of Diagnostic and Interventional Radiology, University Düsseldorf, Medical Faculty, 40225, Düsseldorf, Germany.
| | - Christoph Schleich
- Department of Diagnostic and Interventional Radiology, University Düsseldorf, Medical Faculty, 40225, Düsseldorf, Germany
| | - Styliani Tsiami
- Rheumazentrum Ruhrgebiet Herne, Ruhr University Bochum, Claudiusstr. 45, 44649, Herne, Germany
| | - Anja Müller-Lutz
- Department of Diagnostic and Interventional Radiology, University Düsseldorf, Medical Faculty, 40225, Düsseldorf, Germany
| | - Karl Ludger Radke
- Department of Diagnostic and Interventional Radiology, University Düsseldorf, Medical Faculty, 40225, Düsseldorf, Germany
| | - Neela Holthausen
- Department of Diagnostic and Interventional Radiology, University Düsseldorf, Medical Faculty, 40225, Düsseldorf, Germany
| | - Miriam Frenken
- Department of Diagnostic and Interventional Radiology, University Düsseldorf, Medical Faculty, 40225, Düsseldorf, Germany
| | - Matthias Boschheidgen
- Department of Diagnostic and Interventional Radiology, University Düsseldorf, Medical Faculty, 40225, Düsseldorf, Germany
| | - Gerald Antoch
- Department of Diagnostic and Interventional Radiology, University Düsseldorf, Medical Faculty, 40225, Düsseldorf, Germany
| | - Johanna Mucke
- Policlinic and Hiller Research Unit of Rheumatology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Philipp Sewerin
- Policlinic and Hiller Research Unit of Rheumatology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Juergen Braun
- Rheumazentrum Ruhrgebiet Herne, Ruhr University Bochum, Claudiusstr. 45, 44649, Herne, Germany
| | - Sven Nebelung
- Department of Diagnostic and Interventional Radiology, University Düsseldorf, Medical Faculty, 40225, Düsseldorf, Germany
| | - Xenofon Baraliakos
- Rheumazentrum Ruhrgebiet Herne, Ruhr University Bochum, Claudiusstr. 45, 44649, Herne, Germany
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Abrar DB, Schleich C, Nebelung S, Frenken M, Ullrich T, Radke KL, Antoch G, Vordenbäumen S, Brinks R, Schneider M, Ostendorf B, Sewerin P. Proteoglycan loss in the articular cartilage is associated with severity of joint inflammation in psoriatic arthritis-a compositional magnetic resonance imaging study. Arthritis Res Ther 2020; 22:124. [PMID: 32471515 PMCID: PMC7257142 DOI: 10.1186/s13075-020-02219-7] [Citation(s) in RCA: 7] [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: 02/07/2020] [Accepted: 05/14/2020] [Indexed: 12/27/2022] Open
Abstract
Background Even though cartilage loss is a known feature of psoriatic arthritis (PsA), little is known about its role in the pathogenesis of PsA. Using delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) as a non-invasive marker of the tissue’s proteoglycan content, such early (i.e., pre-morphological) changes have been associated with inflammation in rheumatoid arthritis (RA). Yet, this association has not been studied before in PsA. Methods The metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints of 17 patients with active PsA were evaluated by high-resolution clinical standard morphological and dGEMRIC sequences using a 3T MRI scanner (Magnetom Skyra, Siemens) and a dedicated 16-channel hand coil. Images were analyzed by two independent raters for dGEMRIC indices, PsA MRI scores (PsAMRIS), and total cartilage thickness (TCT). Kendall tau correlation coefficients (τ) were calculated. Results We found significant negative correlations between dGEMRIC indices and total PsAMRIS (τ = − 0.5, p = 0.012), synovitis (τ = − 0.56, p = 0.006), flexor tenosynovitis (τ = − 0.4, p = 0.049), and periarticular inflammation (τ = − 0.72, p < 0.001). Significant positive correlations were found between TCT and dGEMRIC indices at all joint levels (τ = 0.43, p < 0.001). No significant correlations were determined between dGEMRIC indices and bone erosion, bone edema, or bone proliferation. Conclusion In PsA, proteoglycan loss as assessed by dGEMRIC is associated with periarticular inflammation, synovitis, and flexor tenosynovitis, but not with bone erosion or proliferation. Thereby, these findings contribute to in vivo concepts of the disease’s pathophysiology. Beyond morphology, advanced MRI techniques may be used to assess cartilage composition in PsA and to identify early changes in the cartilage as an imaging biomarker with potential application in detection, monitoring, and prediction of outcomes of PsA. Trial registration 2014123117, December 2014.
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Affiliation(s)
- Daniel B Abrar
- University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225, Düsseldorf, Germany.
| | - Christoph Schleich
- University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225, Düsseldorf, Germany
| | - Sven Nebelung
- University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225, Düsseldorf, Germany
| | - Miriam Frenken
- University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225, Düsseldorf, Germany
| | - Tim Ullrich
- University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225, Düsseldorf, Germany
| | - Karl Ludger Radke
- University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225, Düsseldorf, Germany
| | - Gerald Antoch
- University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, D-40225, Düsseldorf, Germany
| | - Stefan Vordenbäumen
- Department and Hiller Research Unit for Rheumatology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Ralph Brinks
- Department and Hiller Research Unit for Rheumatology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Matthias Schneider
- Department and Hiller Research Unit for Rheumatology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Benedikt Ostendorf
- Department and Hiller Research Unit for Rheumatology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Philipp Sewerin
- Department and Hiller Research Unit for Rheumatology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
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21
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Abrar DB, Schleich C, Nebelung S, Frenken M, Radke KL, Vordenbäumen S, Brinks R, Schneider M, Ostendorf B, McGonagle D, Sewerin P. High-resolution MRI of flexor tendon pulleys using a 16-channel hand coil: disease detection and differentiation of psoriatic and rheumatoid arthritis. Arthritis Res Ther 2020; 22:40. [PMID: 32122392 PMCID: PMC7052970 DOI: 10.1186/s13075-020-2135-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [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: 11/27/2019] [Accepted: 02/20/2020] [Indexed: 02/08/2023] Open
Abstract
Background To evaluate the value of 3 Tesla (T) magnetic resonance imaging (MRI) changes of flexor tendon pulleys for the differentiation of psoriatic (PsA) and rheumatoid arthritis (RA), using a novel 16-channel high-resolution hand coil. Methods Seventeen patients with active PsA, 20 patients with active RA, and 16 healthy controls (HC) underwent high-resolution 3 T MRI using the dedicated 16-channel hand coil. Images were analyzed by three independent readers for the degree of inflammatory changes, thickness of flexor tendon pulleys, and comparison to the outcome measures for RA clinical trials (OMERACT) PsA MRI score (PsAMRIS) and to its sub-scores. For correlation analyses, Spearman rho correlation was calculated. Results Flexor tendon pulleys were thicker in PsA than in RA patients (mean difference 0.16 mm, p < 0.001) and HC (mean difference 0.2 mm, p < 0.001) and showed a higher degree of associated inflammatory changes (mean difference from RA 4.7, p = 0.048; mean difference from HC 14.65, p < 0.001). Additionally, there was a strong correlation of accessory pulley inflammation and PsAMRIS and its acute-inflammatory sub-scores, flexor tenosynovitis, synovitis, and periarticular inflammation (for the second digit synovitis ρ = 0.72, flexor tenosynovitis ρ = 0.7, overall PsAMRIS ρ = 0.72, p < 0.01). Similar robust correlations were evident in digits 3–5. Weaker correlations were evident in RA (synovitis ρ = 0.49, flexor tenosynovitis ρ = 0.49, periarticular inflammation ρ = 0.4). Conclusion The assessment of MRI changes of flexor tendon pulleys is potentially beneficial for disease detection in PsA, as well as for its distinction from RA and HC. Trial registration 2014123117, December 2014.
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Affiliation(s)
- Daniel B Abrar
- Institute for Diagnostic and Interventional Radiology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Christoph Schleich
- Institute for Diagnostic and Interventional Radiology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Sven Nebelung
- Institute for Diagnostic and Interventional Radiology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Miriam Frenken
- Institute for Diagnostic and Interventional Radiology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Karl Ludger Radke
- Institute for Diagnostic and Interventional Radiology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Stefan Vordenbäumen
- Policlinic and Hiller Research Unit for Rheumatology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Ralph Brinks
- Policlinic and Hiller Research Unit for Rheumatology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Matthias Schneider
- Policlinic and Hiller Research Unit for Rheumatology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Benedikt Ostendorf
- Policlinic and Hiller Research Unit for Rheumatology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany
| | - Dennis McGonagle
- NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds Teaching Hospitals Trust and The University of Leeds, Leeds, UK
| | - Philipp Sewerin
- Policlinic and Hiller Research Unit for Rheumatology, UKD, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225, Düsseldorf, Germany.
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Radke KL, Colby C, Kates JR, Krider HM, Prescott DM. Establishment and maintenance of the interferon-induced antiviral state: studies in enucleated cells. J Virol 1974; 13:623-30. [PMID: 4362865 PMCID: PMC355347 DOI: 10.1128/jvi.13.3.623-630.1974] [Citation(s) in RCA: 45] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Requirements for the physical presence of the cell's nucleus for the establishment and maintenance of the interferon-induced antiviral state were investigated. Enucleated chicken embryo fibroblasts were obtained by cytochalasin B treatment during centrifugation. The inhibition of vaccinia virus cytoplasmic DNA synthesis, monitored by autoradiography, was used to measure the antiviral activity resulting from interferon treatment. The antiviral state is not established in cells treated with interferon after removal of their nuclei. On the other hand, cells first treated with interferon for 6 or 12 h and then enucleated express the antiviral state. Furthermore, the antiviral state is maintained in enucleated cells for 16 h after enucleation. The antiviral state appears to be more stable in enucleates than in the residual nucleated cells found in the same cultures. Single cells of antiviral populations are found to be either fully permissive or fully restrictive to vaccinia DNA synthesis. The effect of an increasing intracellular multiplicity of infectious virus is to overcome the antiviral cell's block against viral DNA synthesis.
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Radke KL, Siegel EC. Mutation preventing capsular polysaccharide synthesis in Escherichia coli K-12 and its effect on bacteriophage resistance. J Bacteriol 1971; 106:432-7. [PMID: 4929858 PMCID: PMC285113 DOI: 10.1128/jb.106.2.432-437.1971] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
A mutant strain of Escherichia coli K-12 was found in which spontaneous mutation to phage T7 resistance occurred at a very low frequency. T7 resistance in the parental strain from which this mutant was derived resulted from a mutation to excess capsular polysaccharide synthesis. The mutation preventing T7 resistance, non-9, inhibited capsule formation when transduced into capsulated strains. The non-9 mutation was cotransducible with his, the gene order in this region being non-9 his Su-1.
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