Project Details
Projekt
Detection of Early Osteoarthritis by Functional Multiparametric MRI Techniques
Applicant
Privatdozent Dr. Sven Nebelung
Subject Area
Nuclear Medicine, Radiotherapy, Radiobiology
Orthopaedics, Traumatology, Reconstructive Surgery
Orthopaedics, Traumatology, Reconstructive Surgery
Term
from 2019 to 2024
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 417508432
Current clinical standard diagnostic tools are characterized by deficits in the objective evaluation of articular cartilage. In previous studies of this group and others, cartilage assessment using quantitative MRI parameters (qMRI) in combination with a biomechanical stimulus was demonstrated to be diagnostically beneficial. The resulting structural and compositional changes of the tissue (i.e. its response to loading) could be quantified using dedicated MRI sequences and distinct relaxation characteristics (i.e. T1, T1ρ, T2 and T2* mapping, diffusion-associated parameters, dGEMRIC). Beyond these preliminary studies, the aim of the proposed project is to gradually transfer the concept of non-invasive and MRI-based cartilage functionality assessment to the in-vivo situation. Based on an existing prototypical displacement-controlled loading device, the basic scientific validation of the concept is established by designing, constructing and validating an MRI-compatible compressive loading device that integrates a standardized human knee joint and allows the qMRI-based in-situ assessment of a standardized cartilage sample under pressure-controlled uni-axial loading (loading device-1, LD-1). Subsequently, the response-to-loading patterns of native human articular cartilage samples are studied systematically on the basis of the above-mentioned MRI parameters and dedicated post-processing routines, in particular as a function of variations in biomechanical loading regimes and degeneration. Sequentially, the cartilage response to loading of the entire joint is assessed in an intact human cadaver joint using an analogous pressure-controlled compression device (LD-2). This device allows the ongoing in-situ assessment of cartilage functionality in relation to the joint’s axis and configuration (by variable varus / valgus positions). Upon histological, biochemical and biomechanical reference evaluation, cartilage functionality is then classified on the basis of the functional qMRI data and evaluated in its ability to detect early cartilage degeneration. To finalize the concept’s in-vivo translation, a dedicated loading device is designed and constructed that takes in a volunteer’s knee joint (LD-3) to be loaded under simultaneous qMRI evaluation in a pressure-controlled and standardized manner by applying varus / valgus stress. Upon successful validation, the first functional in-vivo qMRI measurements are carried out on volunteers within the framework of the proposed project. Computational modeling approaches that integrate the MRI and reference evaluation data are used to model the relevant loading-induced structural and compositional intra-tissue changes on the basis of an existent anisotropic-hyperelastic constitutive cartilage model.
DFG Programme
Research Grants
