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Zentrum f. Medizinische Physik u. Biomedizinische Technik & MR- Hochfeld - Zentrum. MR- Microscopy of small specimen on a Human 7T-Scanner Andreas Berg. Methodology : hardware. Quality control spatial resolution. - PowerPoint PPT Presentation
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Zentrum f. Medizinische Physik u. Biomedizinische Technik & MR-Hochfeld-Zentrum
MR-Microscopy of small specimenon a Human 7T-Scanner
Andreas Berg
A.Berg, MR-Center 06.04.2011
Quality control spatial resolution
1.) Paraplegia model in rat spine 2.) osteoarthritis: cartilage bone intervert. Disc 3.) teeth and dental composites
Methodology: hardware
MR-microscopy insert on 7T scanner:
Standard whole body scanner:
Phantoms: test structures d < 100 µm
Results Quality control: Spatial Resolution
Phantoms: Test structures d > 1000 µm
A. Berg, Deutsches Patentamt,
München, DE19904635 , 19.08.1999
1,5 cm
First results: Quality Control: spatial Resolution
Silicon grid in Silicon oil
MR-microscopic images of Silicon grid sets in Silicon oil (finest: a/2 = 32 µm)
Left: sagittal view at increased SNR (32 averages )Top: enlarged area trace of profile is indicatedBottom: profile indicating modulation depth Right: sagittal view for a short protocol
Voxel size:50,9 x 25,4 x 200 µm3 !!!
= 2,6 10-4 mm3
= 0,26 10-9 l
< 10-3 Clinical Voxel size(500 x 500 x 2000 µm)
TM = 1,5 min
SNR = 3,15
TM = 87 min
SNR = 16
A. Berg et al. MR-MICROSCOPY ON A HUMAN 7T-SCANNER; ISMRM/ESMRMB 2010, progr nr. 1048,
MR-microscopy vs. histology: Osteoarthritis
MR-microscopy: A. Berg; Samples and referencing: S. Domayer, J. Hofstätter Univ. klinik f. Orthopädie
Osteoarthritis
cartilage-bone interface: MR-microscopy vs histological staining
Histologic staining:Safranin-O
MR-microscopy:TE = 8 msVoxel: 96 x 59 x 240 µm3
MR-microscopy vs histology:
• Intact tissue after measurement
• No damage due to cutting
• No staining necessary
(T2, T1, Diffusivity)
• Low effort,Low preparation - and measurement time
1.) Healthy cartilage (lateral condyle of the knee):
Homogeneous, thick cartilage layer
trabecular network structure
A. Berg, A. Potthast, P. Starewicz, S. Domayer, J. G. Hofstaetter; MR-Microscopy on a human MR-7T Scanner: Methodology and application to medial osteoarthritic samples of the Knee. ECR 2011 Vienna
MR-Microscopy vs. histology
Size: 250 µm - 50 µm
Small degradation areas below the surface
Presumably: areas of fibrillation and loss of proteoglycane
8 mm
osteoarthritic cartilage (medial condyle of the knee):
5
A. Berg, A. Potthast, P. Starewicz, S. Domayer, J. G. Hofstaetter; MR-Microscopy on a human MR-7T Scanner: Methodology and application to medial osteoarthritic samples of the Knee. ECR 2011 Vienna
Voxel size = 51 x 51 x 240 µm3
< 10-3 clinical MRI voxel size (500 x 500 x 2000 µm3 )TSE:3D-MTX: 256x 256 x 47TE = 8.2 ms, TR = 2.3 sTM = 16 min
MR-microscopy:
Small degradation areas below the surface
Presumably: areas of fibrillation and loss of proteoglycane
osteoarthritic cartilage (medial compartment of the knee):
MR-Microscopy vs Histology
A. Berg, A. Potthast, P. Starewicz, S. Domayer, J. G. Hofstaetter; MR-Microscopy on a human MR-7T Scanner: Methodology and application to medial osteoarthritic samples of the Knee. ECR 2011 Vienna
4 mm
3D-multislicing
Pulse sequence:Berg_TSE
Voxel: 51 x 51 x 240 µm3
3D-MTX: 256x 256 x 47TM = 16 min
A. Berg, A. Potthast, P. Starewicz, S. Domayer, J. G. Hofstaetter; MR-Microscopy on a human MR-7T Scanner: Methodology and application to medial osteoarthritic samples of the Knee. ECR 2011 Vienna
13 mm