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High resolution MRI imaging at 9.4 Tesla of the osteochondral unit in a translational model of articular cartilage repair.

Goebel L, Müller A, Bücker A, Madry H - BMC Musculoskelet Disord (2015)

Bottom Line: A 3D SGE sequence with the parameters: TR = 10 ms, TE = 3 ms, FA = 10°, voxel size = 120 × 120 × 120 μm(3) and NEX = 10 resulted in the best fitting for sample size, image quality, scanning time and artifacts.Specific alterations of the osteochondral unit associated with cartilage repair such as persistent drill holes, subchondral bone cysts, sclerosis of the subchondral bone plate and of the subarticular spongiosa and intralesional osteophytes were precisely detected.In particular, 9.4 T is capable of accurately depicting alterations of the subchondral bone that are associated with osteochondral repair.

View Article: PubMed Central - PubMed

Affiliation: Center of Experimental Orthopaedics, Saarland University Medical Center, Kirrberger Straße, Building 37, Homburg/Saar, D-66421, Germany. Lars.Goebel@uks.eu.

ABSTRACT

Background: Non-destructive structural evaluation of the osteochondral unit is challenging. Here, the capability of high-field magnetic resonance imaging (μMRI) at 9.4 Tesla (T) was explored to examine osteochondral repair ex vivo in a preclinical large animal model. A specific aim of this study was to detect recently described alterations of the subchondral bone associated with cartilage repair.

Methods: Osteochondral samples of medial femoral condyles from adult ewes containing full-thickness articular cartilage defects treated with marrow stimulation were obtained after 6 month in vivo and scanned in a 9.4 T μMRI. Ex vivo imaging of small osteochondral samples (typical volume: 1-2 cm(3)) at μMRI was optimised by variation of repetition time (TR), time echo (TE), flip angle (FA), spatial resolution and number of excitations (NEX) from standard MultiSliceMultiEcho (MSME) and three-dimensional (3D) spoiled GradientEcho (SGE) sequences.

Results: A 3D SGE sequence with the parameters: TR = 10 ms, TE = 3 ms, FA = 10°, voxel size = 120 × 120 × 120 μm(3) and NEX = 10 resulted in the best fitting for sample size, image quality, scanning time and artifacts. An isovolumetric voxel shape allowed for multiplanar reconstructions. Within the osteochondral unit articular cartilage, cartilaginous repair tissue and bone marrow could clearly be distinguished from the subchondral bone plate and subarticular spongiosa. Specific alterations of the osteochondral unit associated with cartilage repair such as persistent drill holes, subchondral bone cysts, sclerosis of the subchondral bone plate and of the subarticular spongiosa and intralesional osteophytes were precisely detected.

Conclusions: High resolution, non-destructive ex vivo analysis of the entire osteochondral unit in a preclinical large animal model that is sufficient for further analyses is possible using μMRI at 9.4 T. In particular, 9.4 T is capable of accurately depicting alterations of the subchondral bone that are associated with osteochondral repair.

No MeSH data available.


Related in: MedlinePlus

Schematic illustration of a medial fermoral condyle with a cartilage defect and drill holes. sagittal (a) and axial (b) cross section. In (a) the dashed line indicates the former level of articular cartilage. Each defect (4.0 × 8.0 mm) was treated with six drill holes (diameter 1.0 mm, length 10.0 mm).
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Fig1: Schematic illustration of a medial fermoral condyle with a cartilage defect and drill holes. sagittal (a) and axial (b) cross section. In (a) the dashed line indicates the former level of articular cartilage. Each defect (4.0 × 8.0 mm) was treated with six drill holes (diameter 1.0 mm, length 10.0 mm).

Mentions: Standardized, rectangular full-thickness chondral defects (size 4 mm width x 8 mm length) were created in the weight-bearing area of the medial femoral condyle in each stifle joint and treated with Pridie drilling by introducing six subchondral drill holes with a diameter of 1.0 mm into each defect using a Kirschner wire to a depth of 10 mm in a standardized manner (Figure 1) as described before [9,10,27,29]. Here, outmost caution was taken to meticulously remove the calcified cartilage from the subchondral bone [30,31].Figure 1


High resolution MRI imaging at 9.4 Tesla of the osteochondral unit in a translational model of articular cartilage repair.

Goebel L, Müller A, Bücker A, Madry H - BMC Musculoskelet Disord (2015)

Schematic illustration of a medial fermoral condyle with a cartilage defect and drill holes. sagittal (a) and axial (b) cross section. In (a) the dashed line indicates the former level of articular cartilage. Each defect (4.0 × 8.0 mm) was treated with six drill holes (diameter 1.0 mm, length 10.0 mm).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4404065&req=5

Fig1: Schematic illustration of a medial fermoral condyle with a cartilage defect and drill holes. sagittal (a) and axial (b) cross section. In (a) the dashed line indicates the former level of articular cartilage. Each defect (4.0 × 8.0 mm) was treated with six drill holes (diameter 1.0 mm, length 10.0 mm).
Mentions: Standardized, rectangular full-thickness chondral defects (size 4 mm width x 8 mm length) were created in the weight-bearing area of the medial femoral condyle in each stifle joint and treated with Pridie drilling by introducing six subchondral drill holes with a diameter of 1.0 mm into each defect using a Kirschner wire to a depth of 10 mm in a standardized manner (Figure 1) as described before [9,10,27,29]. Here, outmost caution was taken to meticulously remove the calcified cartilage from the subchondral bone [30,31].Figure 1

Bottom Line: A 3D SGE sequence with the parameters: TR = 10 ms, TE = 3 ms, FA = 10°, voxel size = 120 × 120 × 120 μm(3) and NEX = 10 resulted in the best fitting for sample size, image quality, scanning time and artifacts.Specific alterations of the osteochondral unit associated with cartilage repair such as persistent drill holes, subchondral bone cysts, sclerosis of the subchondral bone plate and of the subarticular spongiosa and intralesional osteophytes were precisely detected.In particular, 9.4 T is capable of accurately depicting alterations of the subchondral bone that are associated with osteochondral repair.

View Article: PubMed Central - PubMed

Affiliation: Center of Experimental Orthopaedics, Saarland University Medical Center, Kirrberger Straße, Building 37, Homburg/Saar, D-66421, Germany. Lars.Goebel@uks.eu.

ABSTRACT

Background: Non-destructive structural evaluation of the osteochondral unit is challenging. Here, the capability of high-field magnetic resonance imaging (μMRI) at 9.4 Tesla (T) was explored to examine osteochondral repair ex vivo in a preclinical large animal model. A specific aim of this study was to detect recently described alterations of the subchondral bone associated with cartilage repair.

Methods: Osteochondral samples of medial femoral condyles from adult ewes containing full-thickness articular cartilage defects treated with marrow stimulation were obtained after 6 month in vivo and scanned in a 9.4 T μMRI. Ex vivo imaging of small osteochondral samples (typical volume: 1-2 cm(3)) at μMRI was optimised by variation of repetition time (TR), time echo (TE), flip angle (FA), spatial resolution and number of excitations (NEX) from standard MultiSliceMultiEcho (MSME) and three-dimensional (3D) spoiled GradientEcho (SGE) sequences.

Results: A 3D SGE sequence with the parameters: TR = 10 ms, TE = 3 ms, FA = 10°, voxel size = 120 × 120 × 120 μm(3) and NEX = 10 resulted in the best fitting for sample size, image quality, scanning time and artifacts. An isovolumetric voxel shape allowed for multiplanar reconstructions. Within the osteochondral unit articular cartilage, cartilaginous repair tissue and bone marrow could clearly be distinguished from the subchondral bone plate and subarticular spongiosa. Specific alterations of the osteochondral unit associated with cartilage repair such as persistent drill holes, subchondral bone cysts, sclerosis of the subchondral bone plate and of the subarticular spongiosa and intralesional osteophytes were precisely detected.

Conclusions: High resolution, non-destructive ex vivo analysis of the entire osteochondral unit in a preclinical large animal model that is sufficient for further analyses is possible using μMRI at 9.4 T. In particular, 9.4 T is capable of accurately depicting alterations of the subchondral bone that are associated with osteochondral repair.

No MeSH data available.


Related in: MedlinePlus