| 1. |
- de Windt, Tommy S, et al.
(författare)
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Is Magnetic Resonance Imaging Reliable in Predicting Clinical Outcome After Articular Cartilage Repair of the Knee?: A Systematic Review and Meta-analysis.
- 2013
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Ingår i: The American journal of sports medicine. - : SAGE Publications. - 1552-3365 .- 0363-5465. ; 41:7, s. 1695-1702
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:While MRI can provide a detailed morphological evaluation after articular cartilage repair, its additional value in determining clinical outcome has yet to be determined. PURPOSE:To evaluate the correlation between MRI and clinical outcome after cartilage repair and to identify parameters that are most important in determining clinical outcome. STUDY DESIGN:Systematic review and meta-analysis. METHODS:A systematic search was performed in Embase, MEDLINE, and the Cochrane Collaboration. Articles were screened for relevance and appraised for quality. Guidelines in the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) Statement were used. Chi-square tests were performed to find variables that could determine correlation between clinical and radiological parameters. RESULTS:A total of 32 articles (total number of patients, 1019) were included. A majority (81%) were case series or cohort studies that used similar standardized MRI techniques. The mean Coleman score was 63 (range, 42-96). For the majority of MRI parameters, limited or no correlation was found. Nine studies (28%) found a correlation between clinical outcome and the composite magnetic resonance observation of cartilage repair tissue (MOCART) or Henderson score and 7 (22%) with defect fill. In 5 studies, a weak to moderate correlation was found between clinical outcome and the T2 index (mean Pearson coefficient r = .53). CONCLUSION:Strong evidence to determine whether morphological MRI is reliable in predicting clinical outcome after cartilage repair is lacking. Future research aiming specifically at clinical sensitivity of advanced morphological and biochemical MRI techniques after articular cartilage repair could be of great importance to the field.
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| 2. |
- Moser, Ewald, et al.
(författare)
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7-T MR-from research to clinical applications?
- 2012
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Ingår i: NMR in Biomedicine. - : Wiley. - 0952-3480. ; 25:5, s. 695-716
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Forskningsöversikt (refereegranskat)abstract
- Over 20?000 MR systems are currently installed worldwide and, although the majority operate at magnetic fields of 1.5?T and below (i.e. about 70%), experience with 3-T (in high-field clinical diagnostic imaging and research) and 7-T (research only) human MR scanners points to a future in functional and metabolic MR diagnostics. Complementary to previous studies, this review attempts to provide an overview of ultrahigh-field MR research with special emphasis on emerging clinical applications at 7?T. We provide a short summary of the technical development and the current status of installed MR systems. The advantages and challenges of ultrahigh-field MRI and MRS are discussed with special emphasis on radiofrequency inhomogeneity, relaxation times, signal-to-noise improvements, susceptibility effects, chemical shifts, specific absorption rate and other safety issues. In terms of applications, we focus on the topics most likely to gain significantly from 7-T MR, i.e. brain imaging and spectroscopy and musculoskeletal imaging, but also body imaging, which is particularly challenging. Examples are given to demonstrate the advantages of susceptibility-weighted imaging, time-of-flight MR angiography, high-resolution functional MRI, 1H and 31P MRSI in the human brain, sodium and functional imaging of cartilage and the first results (and artefacts) using an eight-channel body array, suggesting future areas of research that should be intensified in order to fully explore the potential of 7-T MR systems for use in clinical diagnosis. Copyright (C) 2011 John Wiley & Sons, Ltd.
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| 3. |
- Pierce, David M., et al.
(författare)
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DT-MRI Based Computation of Collagen Fiber Deformation in Human Articular Cartilage : A Feasibility Study
- 2010
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Ingår i: Annals of Biomedical Engineering. - : Springer Science and Business Media LLC. - 0090-6964 .- 1573-9686. ; 38:7, s. 2447-2463
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Tidskriftsartikel (refereegranskat)abstract
- Accurate techniques for simulating the deformation of soft biological tissues are an increasingly valuable tool in many areas of biomechanical analysis and medical image computing. To model the complex morphology and response of articular cartilage, a hyperviscoelastic (dispersed) fiber-reinforced constitutive model is employed to complete two specimen-specific finite element (FE) simulations of an indentation experiment, with and without considering fiber dispersion. Ultra-high field Diffusion Tensor Magnetic Resonance Imaging (17.6 T DT-MRI) is performed on a specimen of human articular cartilage before and after indentation to similar to 20% compression. Based on this DT-MRI data, we detail a novel FE approach to determine the geometry (edge detection from first eigenvalue), the meshing (semi-automated smoothing of DTI measurement voxels), and the fiber structural input (estimated principal fiber direction and dispersion). The global and fiber fabric deformations of both the un-dispersed and dispersed fiber models provide a satisfactory match to that estimated experimentally. In both simulations, the fiber fabric in the superficial and middle zones becomes more aligned with the articular surface, although the dispersed model appears more consistent with the literature. In the future, a multi-disciplinary combination of DT-MRI and numerical simulation will allow the functional state of articular cartilage to be determined in vivo.
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| 4. |
- Wenger, Andrea, et al.
(författare)
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Meniscus Body Position, Size, and Shape in Persons With and Persons Without Radiographic Knee Osteoarthritis: Quantitative Analyses of Knee Magnetic Resonance Images From the Osteoarthritis Initiative
- 2013
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 1529-0131 .- 0004-3591. ; 65:7, s. 1804-1811
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveTo quantitatively evaluate the position, size, and shape of the menisci in subjects with radiographic knee osteoarthritis (OA) compared to subjects without OA, using magnetic resonance imaging (MRI). MethodsWe studied the right knees of 39 Osteoarthritis Initiative participants (24 women and 15 men with a mean age of 59.6 +/- 8.7 years) with medial compartment radiographic tibiofemoral OA (Kellgren/Lawrence grade of 2 or 3). Subjects were matched individually for age, sex, and height to controls without knee OA and without risk factors for knee OA. The right knees of the controls were used as references. One observer performed manual segmentation of the tibial plateau and the medial and lateral meniscus based on a coronally reconstructed double-echo steady-state sequence with water excitation, focusing on 5 central 3T MRIs. ResultsIn OA knees, there was less meniscal coverage of the medial tibial plateau (435 mm(2) versus 515 mm(2); P = 0.0004), the medial meniscus body showed more extrusion (2.64 mm versus 0.53 mm; P < 0.0001), and the peripheral margin had a more convex shape, i.e., bulged more (mean 0.61 mm versus 0.27 mm; P < 0.0001). The thickness or volume of the medial meniscus body of OA knees did not differ substantially from reference knees. In contrast, in OA knees the lateral meniscus body had a larger volume (mean 266 mm(3) versus 224 mm(3); P = 0.0005) and extruded more (mean 1.16 mm versus -1.01 mm; P < 0.0001), and the external margin bulged more (mean 0.53 mm versus 0.35 mm; P < 0.0001), than in reference knees. ConclusionOur findings indicate altered meniscal position and shape (i.e., more bulging) in both compartments in medial compartment knee OA. These changes may be important features of OA pathogenesis and/or disease consequences.
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