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High-resolution measurements of the multilayer ultra-structure of articular cartilage and their translational potential.

He B, Wu JP, Kirk TB, Carrino JA, Xiang C, Xu J - Arthritis Res. Ther. (2014)

Bottom Line: Current musculoskeletal imaging techniques usually target the macro-morphology of articular cartilage or use histological analysis.These techniques are able to reveal advanced osteoarthritic changes in articular cartilage but fail to give detailed information to distinguish early osteoarthritis from healthy cartilage, and this necessitates high-resolution imaging techniques measuring cells and the extracellular matrix within the multilayer structure of articular cartilage.This review provides a comprehensive exploration of the cellular components and extracellular matrix of articular cartilage as well as high-resolution imaging techniques, including magnetic resonance image, electron microscopy, confocal laser scanning microscopy, second harmonic generation microscopy, and laser scanning confocal arthroscopy, in the measurement of multilayer ultra-structures of articular cartilage.

View Article: PubMed Central - HTML - PubMed

ABSTRACT
Current musculoskeletal imaging techniques usually target the macro-morphology of articular cartilage or use histological analysis. These techniques are able to reveal advanced osteoarthritic changes in articular cartilage but fail to give detailed information to distinguish early osteoarthritis from healthy cartilage, and this necessitates high-resolution imaging techniques measuring cells and the extracellular matrix within the multilayer structure of articular cartilage. This review provides a comprehensive exploration of the cellular components and extracellular matrix of articular cartilage as well as high-resolution imaging techniques, including magnetic resonance image, electron microscopy, confocal laser scanning microscopy, second harmonic generation microscopy, and laser scanning confocal arthroscopy, in the measurement of multilayer ultra-structures of articular cartilage. This review also provides an overview for micro-structural analysis of the main components of normal or osteoarthritic cartilage and discusses the potential and challenges associated with developing non-invasive high-resolution imaging techniques for both research and clinical diagnosis of early to late osteoarthritis.

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Magnetic resonance image of normal articular cartilage. Sagittal fatsaturated intermediate-weighted fast spin-echo - repetition time/echo time:3100/35 - shows normal articular cartilage at the patellofemoral joint withclear demarcation between the articular cartilage and the subchondral bone.Note three-layered cartilage appearance: deeper dark layer (arrowhead),intermediate bright layer (long arrow), and superficial dark layer (shortarrow) of lamina splendans.
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Figure 2: Magnetic resonance image of normal articular cartilage. Sagittal fatsaturated intermediate-weighted fast spin-echo - repetition time/echo time:3100/35 - shows normal articular cartilage at the patellofemoral joint withclear demarcation between the articular cartilage and the subchondral bone.Note three-layered cartilage appearance: deeper dark layer (arrowhead),intermediate bright layer (long arrow), and superficial dark layer (shortarrow) of lamina splendans.

Mentions: MRI techniques are capable of both directly and indirectly visualizing cartilagestructures. If one accounts for the limitations inherent in MRI, the techniqueprovides a non-invasive means of evaluating the internal structure of thecartilage matrix. Multilayered differentiation is possible in thicker-cartilageareas, such as in patella on the high-resolution and high-field strength imaging(Figure 2). More commonly, articular cartilage has atrilaminar appearance on conventional fluid-sensitive MRI techniques, as alow-signal deep (tidemark and radial zone) layer, a thicker intermediate to brightmiddle layer (deep zone), and a thin low-signal surface layer (superficial andmiddle zones). This regional variation in the signal intensity is due largely toT2 value variations caused by the orientation of the collagen fibrils relative tothe magnetic field [23]. There is a link between tissue architecture and the MRI image bydemonstrating T2 anisotropy within cartilage [24]. When images are acquired with the articular surface perpendicular tothe magnetic field (B0), the trilaminar appearance is nicely seen witha higher-signal intensity or intermediate transitional layer (thicker middlelayer), which separates the low-signal-intensity surface from the low-signalintensity deep layer adjacent to the subchondral bone. Depth-dependent variabilityin T2 causes a characteristic layered appearance on MRI images of cartilage. Theselayers reflect the continuous variation in T2 values across the thickness of thetissue [25]. T1 relaxation, proton diffusion, and proton density have only minimalinfluence on the tissue contrast [26]. The minimum T2 relaxation time in articular cartilage is relativelyshort, approximately 10 msec. T2 anisotropy is due to the influence of matrixstructure on water mobility. As a result, T2 value is the major determinant of thetissue contrast even on T1-weighted and proton density-weighted images [27]. Changes in T2 correlate with changes in the matrix orientation asdisplayed on fracture-sectioned cartilage on scanning electron microscopy (SEM) [28]. Changes in T2 correlate with changes in polarized light microscopy(PLM) [29]. PLM is limited by the use of routine sectioning which cuts through thethree-dimensional organization of cartilage. T2 is neither uniform nor constant.It is determined in large part by the orientation relative to B0 ofboth the joint surface and the internal structure of the matrix. This createspredictable challenges to interpreting the significance of T2 measurements. Normalvariations in cartilage signal due to underlying bony curvatures and collagenorientation relative to the magnetic field are smooth and gradual, whereas truecartilage abnormalities usually demonstrate abrupt signal change apart fromaltered morphology. The various cartilage lesions detectable by MRI includechondromalacia, fibrocartilage formation, chondrocalcinosis, fissuring, partialthickness defect, flaps, delamination, and full-thickness cartilage loss.


High-resolution measurements of the multilayer ultra-structure of articular cartilage and their translational potential.

He B, Wu JP, Kirk TB, Carrino JA, Xiang C, Xu J - Arthritis Res. Ther. (2014)

Magnetic resonance image of normal articular cartilage. Sagittal fatsaturated intermediate-weighted fast spin-echo - repetition time/echo time:3100/35 - shows normal articular cartilage at the patellofemoral joint withclear demarcation between the articular cartilage and the subchondral bone.Note three-layered cartilage appearance: deeper dark layer (arrowhead),intermediate bright layer (long arrow), and superficial dark layer (shortarrow) of lamina splendans.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4061724&req=5

Figure 2: Magnetic resonance image of normal articular cartilage. Sagittal fatsaturated intermediate-weighted fast spin-echo - repetition time/echo time:3100/35 - shows normal articular cartilage at the patellofemoral joint withclear demarcation between the articular cartilage and the subchondral bone.Note three-layered cartilage appearance: deeper dark layer (arrowhead),intermediate bright layer (long arrow), and superficial dark layer (shortarrow) of lamina splendans.
Mentions: MRI techniques are capable of both directly and indirectly visualizing cartilagestructures. If one accounts for the limitations inherent in MRI, the techniqueprovides a non-invasive means of evaluating the internal structure of thecartilage matrix. Multilayered differentiation is possible in thicker-cartilageareas, such as in patella on the high-resolution and high-field strength imaging(Figure 2). More commonly, articular cartilage has atrilaminar appearance on conventional fluid-sensitive MRI techniques, as alow-signal deep (tidemark and radial zone) layer, a thicker intermediate to brightmiddle layer (deep zone), and a thin low-signal surface layer (superficial andmiddle zones). This regional variation in the signal intensity is due largely toT2 value variations caused by the orientation of the collagen fibrils relative tothe magnetic field [23]. There is a link between tissue architecture and the MRI image bydemonstrating T2 anisotropy within cartilage [24]. When images are acquired with the articular surface perpendicular tothe magnetic field (B0), the trilaminar appearance is nicely seen witha higher-signal intensity or intermediate transitional layer (thicker middlelayer), which separates the low-signal-intensity surface from the low-signalintensity deep layer adjacent to the subchondral bone. Depth-dependent variabilityin T2 causes a characteristic layered appearance on MRI images of cartilage. Theselayers reflect the continuous variation in T2 values across the thickness of thetissue [25]. T1 relaxation, proton diffusion, and proton density have only minimalinfluence on the tissue contrast [26]. The minimum T2 relaxation time in articular cartilage is relativelyshort, approximately 10 msec. T2 anisotropy is due to the influence of matrixstructure on water mobility. As a result, T2 value is the major determinant of thetissue contrast even on T1-weighted and proton density-weighted images [27]. Changes in T2 correlate with changes in the matrix orientation asdisplayed on fracture-sectioned cartilage on scanning electron microscopy (SEM) [28]. Changes in T2 correlate with changes in polarized light microscopy(PLM) [29]. PLM is limited by the use of routine sectioning which cuts through thethree-dimensional organization of cartilage. T2 is neither uniform nor constant.It is determined in large part by the orientation relative to B0 ofboth the joint surface and the internal structure of the matrix. This createspredictable challenges to interpreting the significance of T2 measurements. Normalvariations in cartilage signal due to underlying bony curvatures and collagenorientation relative to the magnetic field are smooth and gradual, whereas truecartilage abnormalities usually demonstrate abrupt signal change apart fromaltered morphology. The various cartilage lesions detectable by MRI includechondromalacia, fibrocartilage formation, chondrocalcinosis, fissuring, partialthickness defect, flaps, delamination, and full-thickness cartilage loss.

Bottom Line: Current musculoskeletal imaging techniques usually target the macro-morphology of articular cartilage or use histological analysis.These techniques are able to reveal advanced osteoarthritic changes in articular cartilage but fail to give detailed information to distinguish early osteoarthritis from healthy cartilage, and this necessitates high-resolution imaging techniques measuring cells and the extracellular matrix within the multilayer structure of articular cartilage.This review provides a comprehensive exploration of the cellular components and extracellular matrix of articular cartilage as well as high-resolution imaging techniques, including magnetic resonance image, electron microscopy, confocal laser scanning microscopy, second harmonic generation microscopy, and laser scanning confocal arthroscopy, in the measurement of multilayer ultra-structures of articular cartilage.

View Article: PubMed Central - HTML - PubMed

ABSTRACT
Current musculoskeletal imaging techniques usually target the macro-morphology of articular cartilage or use histological analysis. These techniques are able to reveal advanced osteoarthritic changes in articular cartilage but fail to give detailed information to distinguish early osteoarthritis from healthy cartilage, and this necessitates high-resolution imaging techniques measuring cells and the extracellular matrix within the multilayer structure of articular cartilage. This review provides a comprehensive exploration of the cellular components and extracellular matrix of articular cartilage as well as high-resolution imaging techniques, including magnetic resonance image, electron microscopy, confocal laser scanning microscopy, second harmonic generation microscopy, and laser scanning confocal arthroscopy, in the measurement of multilayer ultra-structures of articular cartilage. This review also provides an overview for micro-structural analysis of the main components of normal or osteoarthritic cartilage and discusses the potential and challenges associated with developing non-invasive high-resolution imaging techniques for both research and clinical diagnosis of early to late osteoarthritis.

Show MeSH
Related in: MedlinePlus