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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

Sclerosis of the subarticular spongiosa at 6 month after surgery using μMRI at 9.4 T. Sclerosis of the subarticular spongiosa (# - area between dashed lines) was observed in 95% of the osteochondral samples after marrow stimulation. Asterisks (*) indicate the extent of the cartilage defect. Persisting drill holes ($). Subsequent coronal planes (a, b). SGE sequence, isotropic voxel size 120 μm3. Scale bar = 4 mm.
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Fig10: Sclerosis of the subarticular spongiosa at 6 month after surgery using μMRI at 9.4 T. Sclerosis of the subarticular spongiosa (# - area between dashed lines) was observed in 95% of the osteochondral samples after marrow stimulation. Asterisks (*) indicate the extent of the cartilage defect. Persisting drill holes ($). Subsequent coronal planes (a, b). SGE sequence, isotropic voxel size 120 μm3. Scale bar = 4 mm.

Mentions: A sclerosis of the subchondral bone plate and subarticular spongiosa was detected in the majority of the osteochondral specimen (n = 36; Figure 10). It was described as thickening of the subchondral bone plate or as predominance of the subarticular spongiosa, supplanting the fatty bone marrow. Rarely, the subchondral bone was completely restored following marrow stimulation (n = 1).Figure 10


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)

Sclerosis of the subarticular spongiosa at 6 month after surgery using μMRI at 9.4 T. Sclerosis of the subarticular spongiosa (# - area between dashed lines) was observed in 95% of the osteochondral samples after marrow stimulation. Asterisks (*) indicate the extent of the cartilage defect. Persisting drill holes ($). Subsequent coronal planes (a, b). SGE sequence, isotropic voxel size 120 μm3. Scale bar = 4 mm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig10: Sclerosis of the subarticular spongiosa at 6 month after surgery using μMRI at 9.4 T. Sclerosis of the subarticular spongiosa (# - area between dashed lines) was observed in 95% of the osteochondral samples after marrow stimulation. Asterisks (*) indicate the extent of the cartilage defect. Persisting drill holes ($). Subsequent coronal planes (a, b). SGE sequence, isotropic voxel size 120 μm3. Scale bar = 4 mm.
Mentions: A sclerosis of the subchondral bone plate and subarticular spongiosa was detected in the majority of the osteochondral specimen (n = 36; Figure 10). It was described as thickening of the subchondral bone plate or as predominance of the subarticular spongiosa, supplanting the fatty bone marrow. Rarely, the subchondral bone was completely restored following marrow stimulation (n = 1).Figure 10

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