S Nebelung1, B Sondern2, H Jahr3, M Tingart4, M Knobe5, J Thüring6, C Kuhl7, D Truhn8. 1. Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany. Electronic address: snebelung@ukaachen.de. 2. Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany. Electronic address: bjoern.sondern@rwth-aachen.de. 3. Department of Orthopaedics, Aachen University Hospital, Aachen, Germany. Electronic address: hjahr@ukaachen.de. 4. Department of Orthopaedics, Aachen University Hospital, Aachen, Germany. Electronic address: mtingart@ukaachen.de. 5. Department of Orthopaedic Trauma, Aachen University Hospital, Aachen, Germany. Electronic address: mknobe@ukaachen.de. 6. Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany. Electronic address: jthuering@ukaachen.de. 7. Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany. Electronic address: ckuhl@ukaachen.de. 8. Department of Diagnostic and Interventional Radiology, Aachen University Hospital, Aachen, Germany. Electronic address: dtruhn@ukaachen.de.
Abstract
OBJECTIVE: To define the physiological response to sequential loading and unloading in histologically intact human articular cartilage using serial T1ρ mapping, as T1ρ is considered to indicate the tissue's macromolecular content. METHOD: 18 macroscopically intact cartilage-bone samples were obtained from the central lateral femoral condyles of 18 patients undergoing total knee replacement. Serial T1ρ mapping was performed on a clinical 3.0-T MRI system using a modified prostate coil. Spin-lock multiple gradient-echo sequences prior to, during and after standardized indentation loading (displacement controlled, strain 20%) were used to obtain seven serial T1ρ maps: unloaded (δ0), quasi-statically loaded (indentation1-indentation3) and under subsequent relaxation (relaxation1-relaxation3). After manual segmentation, zonal and regional regions-of-interest were defined. ROI-specific relative changes were calculated and statistically assessed using paired t-tests. Histological (Mankin classification) and biomechanical (unconfined compression) evaluations served as references. RESULTS: All samples were histologically and biomechanically grossly intact (Mankin sum: 1.8 ± 1.2; Young's Modulus: 0.7 ± 0.4 MPa). Upon loading, T1ρ consistently increased throughout the entire sample thickness, primarily subpistonally (indentation1 [M ± SD]: 9.5 ± 7.8% [sub-pistonal area, SPA] vs 4.2 ± 5.8% [peri-pistonal area, PPA]; P < 0.001). T1ρ further increased with ongoing loading (indentation3: 14.1 ± 8.1 [SPA] vs 7.7 ± 5.9% [PPA]; P < 0.001). Even upon unloading (i.e., relaxation), T1ρ persistently increased in time. CONCLUSION: Serial T1ρ-mapping reveals distinct and complex zonal and regional changes in articular cartilage as a function of loading and unloading. Thereby, longitudinal adaptive processes in hyaline cartilage become evident, which may be used for the tissue's non-invasive functional characterization by T1ρ.
OBJECTIVE: To define the physiological response to sequential loading and unloading in histologically intact humanarticular cartilage using serial T1ρ mapping, as T1ρ is considered to indicate the tissue's macromolecular content. METHOD: 18 macroscopically intact cartilage-bone samples were obtained from the central lateral femoral condyles of 18 patients undergoing total knee replacement. Serial T1ρ mapping was performed on a clinical 3.0-T MRI system using a modified prostate coil. Spin-lock multiple gradient-echo sequences prior to, during and after standardized indentation loading (displacement controlled, strain 20%) were used to obtain seven serial T1ρ maps: unloaded (δ0), quasi-statically loaded (indentation1-indentation3) and under subsequent relaxation (relaxation1-relaxation3). After manual segmentation, zonal and regional regions-of-interest were defined. ROI-specific relative changes were calculated and statistically assessed using paired t-tests. Histological (Mankin classification) and biomechanical (unconfined compression) evaluations served as references. RESULTS: All samples were histologically and biomechanically grossly intact (Mankin sum: 1.8 ± 1.2; Young's Modulus: 0.7 ± 0.4 MPa). Upon loading, T1ρ consistently increased throughout the entire sample thickness, primarily subpistonally (indentation1 [M ± SD]: 9.5 ± 7.8% [sub-pistonal area, SPA] vs 4.2 ± 5.8% [peri-pistonal area, PPA]; P < 0.001). T1ρ further increased with ongoing loading (indentation3: 14.1 ± 8.1 [SPA] vs 7.7 ± 5.9% [PPA]; P < 0.001). Even upon unloading (i.e., relaxation), T1ρ persistently increased in time. CONCLUSION: Serial T1ρ-mapping reveals distinct and complex zonal and regional changes in articular cartilage as a function of loading and unloading. Thereby, longitudinal adaptive processes in hyaline cartilage become evident, which may be used for the tissue's non-invasive functional characterization by T1ρ.
Authors: Sven Nebelung; Manuel Post; Matthias Knobe; Markus Tingart; Pieter Emans; Johannes Thüring; Christiane Kuhl; Daniel Truhn Journal: Sci Rep Date: 2019-04-11 Impact factor: 4.379
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Authors: Tobias Hafner; Justus Schock; Manuel Post; Daniel Benjamin Abrar; Philipp Sewerin; Kevin Linka; Matthias Knobe; Christiane Kuhl; Daniel Truhn; Sven Nebelung Journal: Sci Rep Date: 2020-09-15 Impact factor: 4.379
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Authors: Gustav Müller-Franzes; Teresa Nolte; Malin Ciba; Justus Schock; Firas Khader; Andreas Prescher; Lena Marie Wilms; Christiane Kuhl; Sven Nebelung; Daniel Truhn Journal: Diagnostics (Basel) Date: 2022-03-11