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RAPID 3D CHARACTERIZATION OF CARTILAGE, BONE QUALITY & SCAFFOLD RAPID 3D CHARACTERIZATION OF CARTILAGE, BONE QUALITY & SCAFFOLD
TO SUBMICRON RESOLUTION, WITH A NOVEL MICROCT TO SUBMICRON RESOLUTION, WITH A NOVEL MICROCT TO SUBMICRON RESOLUTION, WITH A NOVEL MICROCT TO SUBMICRON RESOLUTION, WITH A NOVEL MICROCT S H Lau1, M. Chandrasekaran2, V. Fan3 , M. Islam3 , S. Candell1, T. Case1, L. Chitra2, T. Fong1, H. Chang1, W. Broderick1
1Xradia Inc, Concord, CA, USA 2Bio-scaffold International Pte. Ltd, Singapore; 2Bio-scaffold International Pte. Ltd, Singapore;
3 Faculty of Dentistry, National University of SingaporeEmail Contact: shlau@xradia.comEmail Contact: shlau@xradia.com
AbstractAbstract Results & DiscussionResults & DiscussionThe current study is focused on developing a new rapid non invasive
AbstractAbstract Results & DiscussionResults & Discussion
Characterizing Cartilage Thickness Characterizing Cartilage Thickness Human Cancerous Bone Quality EvaluationHuman Cancerous Bone Quality EvaluationThe current study is focused on developing a new rapid non invasive
3D imaging technique for bone quality, bioscaffold, cartilage and its
related drug efficacy evaluation. Bone quality evaluation is critical in
patients suspected with osteoporosis or those treated with synthetic
Characterizing Cartilage Thickness without Contrast Agent in Murine ModelCharacterizing Cartilage Thickness without Contrast Agent in Murine Model
Human Cancerous Bone Quality EvaluationHuman Cancerous Bone Quality Evaluation
Remains of PLGA patients suspected with osteoporosis or those treated with synthetic
scaffolds for restoration of bone. Similarly success of synthetic
scaffolds depends much on the micro architecture of the scaffold.
These evaluation plus those involving cartilage thickness in
Fig 5 compares CT
Remains of PLGA scaffold in trabeculae
These evaluation plus those involving cartilage thickness in
osteoarthritis are mainly carried out with conventional histology, which
requires experienced personnel and time consuming sample
preparation techniques. In addition, histology studies can take up to a
compares CT images of a rat knee joint ( a & c) with the
b5apreparation techniques. In addition, histology studies can take up to a
few weeks, results are often operator dependant, and are only
available as individual 2D slices. While in recent years there are
crack
Fig. 2 MicroCT 3D image of cancerous bone sample extracted for
c) with the corresponding MRI (b )and conventional
several publications on the use of MicroCT for such evaluation, the
biggest deficiency of conventional microCT is the lack of contrast and
resolution to detect fine microstructures on bones and low Z ( low
Fig. 2 MicroCT 3D image of cancerous bone sample extracted for analyzing the quality for implant placement @ 0.7 µµµµm detector resolution
conventional histology slides (d)
dcresolution to detect fine microstructures on bones and low Z ( low
contrast) bioscaffold materials and soft tissue. It is also not possible to
image cartilage without contrast enhancing agents.Fig 6 shows CT
dcPLGA Scaffold remnants
PLGA Scaffold remnants
In the current work we have used a novel microCT system for rapid
virtual histology in 3D for bone quality, cartilage and scaffold
microchannel evaluation to submicron pixel resolution, without contrast
Fig 6 shows CT slices of a rat tibia demonstrating Low Density
bone (gray
Compact bone
microchannel evaluation to submicron pixel resolution, without contrast
agents. Examples using human and murine bones will be illustrated,
including a clinical study involving a human cancerous bone after
bioscaffold implant and its comparison with conventional histology
demonstrating high contrast imaging of cartilage-bone b
bone (gray regions)
Lack of Osteocytes
Compact Bone (bright regions)bioscaffold implant and its comparison with conventional histology
R
C
S
1 µµµµm
cartilage-bone interface (a & b) and the quantitative
Fig 3a microCT slice of bone sample @ 0.7µµµµm 6a
ba b
regions)
MethodsMethodsS
100
quantitative evaluation of cartilage layer thickness
Evaluation of the bone sample shows trabecular bone
structure with a cortical layer similar to Type III bone
Fig 3a microCT slice of bone sample @ 0.7µµµµm resolution, compared with conventional histology (3b)
100 µm
Four different samples are used in this study to test the use of the
novel MicroCT as a possible means for rapid 3D imaging technique for
bone quality and bioscaffold evaluation. These includes:
thickness without the aid of contrast agents (c & d )
structure with a cortical layer similar to Type III bone
structure suited for implant placement.
The Fig 3b shows the connective tissues, the cancerousdc
Evaluation of cartilage degeneration in osteoarthritis
using murine model is possible with a microCT (only with
bone quality and bioscaffold evaluation. These includes:
1.Human Cancerous Bone extracted from a dental alveolar socket after
placement of bioscaffold for 4 months in the socket
agents (c & d )The Fig 3b shows the connective tissues, the cancerous
bone and the cortical layers in the histology which can be
also clearly seen in the CT slice (Fig 3a) where the
cancerous bone is seen as a dull grey region while the
d
contrast agents), with a MRI or through conventional
histology. The novel high contrast CT can image cartilage
structure and its bone interface quickly without contrast
placement of bioscaffold for 4 months in the socket
2.Rat knee joint for cartilage imaging in Osteoarthritis
3.Resorption Pit Assays for Osteoporosis
4.Bioscaffold microchannel and microporosity evaluation after
cancerous bone is seen as a dull grey region while the
cortical boundaries as white regions. The osteoclasts spread
on the cancerous regions (dots seen on the dull grayish
surface) is also seen. The connective tissues are seen as
NOD R
f∆
=
structure and its bone interface quickly without contrast
agent (Fig 5 & 6) [2]. Fig 5 compares the novel CT
imaging at low and high resolution and the equivalent
images from MRI and conventional histology. MRI are
4.Bioscaffold microchannel and microporosity evaluation after
fabrication and post processing.surface) is also seen. The connective tissues are seen as
dark grey regions identical to porosity while scaffold remains
are seen within the connective tissue regions.N
OD Rf
λ
∆=
images from MRI and conventional histology. MRI are
typically very low resolution, while conventional histology
generally takes 2 to 3 weeks to prepare.
.
The patient had a placement of bioscaffold (fig 4) in the socket after
Extraction for about 4 months within which sufficient bone volume was
achieved in the socket. Patient opted for an implant placement and a
are seen within the connective tissue regions.
While the conventional histology required extensive sample
preparation techniques along with staining to identify these
500
.
1 µµµµm
achieved in the socket. Patient opted for an implant placement and a
bone piece was harvested from the proposed implant site to ensure
bone quality and absence of any inflammation. The bone sample was
analyzed both using conventional histology and micro CT which is
Characterizing Bone Resorption pits in Osteoporosis AssaysCharacterizing Bone Resorption pits in Osteoporosis Assays
preparation techniques along with staining to identify these
(up to a few weeks), the microCT was able to provide the
data rapidly (couple of hours) and with very little sample
preparation.500 µm
Characterizing 3D Microchannels in BioscaffoldsCharacterizing 3D Microchannels in Bioscaffolds
analyzed both using conventional histology and micro CT which is
shown in the Figures 2 & 3
Rat knee joints were harvested, fixed in paraffin and imaged at different
preparation.
BioscaffoldsBioscaffoldsRat knee joints were harvested, fixed in paraffin and imaged at different
Resolutions (Fig 5 to 7). Comparison with histology is shown.
In case of bioscaffold, the fabricated samples were analyzed using x-In case of bioscaffold, the fabricated samples were analyzed using x-
ray microCT to characterize the micro porosities and macro channels
present. The slices were taken both in the vertical and horizontal
directions to evaluate the distribution of pores and pore sizes while the7a b
directions to evaluate the distribution of pores and pore sizes while the
3 dimensional images were constructed from the slices to analyze the
macro channels in the scaffold. Conventional imaging technique can
only produce 2 D images which will be giving information on one planeWith detector pixel resolution to < 1 micron range,
microscopic bone resorption pits may be detected in drug
7a b
ConclusionConclusion
only produce 2 D images which will be giving information on one plane
alone (Fig 4).microscopic bone resorption pits may be detected in drug
assays for osteoporosis in murine models ( Fig 7).b
ConclusionConclusionFrom the above figures and discussion, it is evident that
Fig 1: Apparatus: schematic of the
aFrom the above figures and discussion, it is evident that
the novel microCT is an effective tool for characterizing any
solids with very low attenuation factors including human
cancerous bones, murine cartilage and bones and
300 µm
100 µmFig 4 a b & c 3D and 2D CT images of the
Bioscaffold surface and the CT slice image.
schematic of the novel microCT with unique high resolution and
ca
cancerous bones, murine cartilage and bones and
resorbable bio-scaffolds non-invasively. As microCT
technique also requires little or no sample preparation
thereby minimizing the time required while preserving the
Bioscaffold surface and the CT slice image.
It can be clearly seen from the images, that microCT
combines the advantage of conventional optical
microscope, scanning electron microscope and that of a
resolution and high contrast optics
The apparatus used for this study (Fig 1) is based on the Xradia’s
MicroXCT[1], which is capable of submicron detector pixel resolution.
thereby minimizing the time required while preserving the
integrity of sample and information required. It is therefore
envisioned that this technique could supplement
conventional histology for these assays in preclinical and
microscope, scanning electron microscope and that of a
confocal microscope, without the associated sample
preparation requirements. Fig 4a shows the 3 D structure
of the scaffold with macro channel and micro porosity onMicroXCT[1], which is capable of submicron detector pixel resolution.
Unlike conventional MicroCTs which uses point projection technique
where resolution is limited by source spot size and its sample-source
distance- resolution of the novel microCT is not dependant on these
conventional histology for these assays in preclinical and
possibly clinical applications.
References
of the scaffold with macro channel and micro porosity on
the sample surface. The fig 4b clearly shows the macro
channel size and configuration while also reflecting thedistance- resolution of the novel microCT is not dependant on these
parameters. Relatively large biological materials of several mm
diameter may be imaged to 1 micron resolution. With
PhaseEnhancedTM optics, significant increase in contrast is realized,
References[1] S H Lau, et al., : “Virtual Non Invasive 3D Imaging of Biomaterials and Soft Tissue
with a Novel High Contrast CT, with Resolution from mm to sub 30 nm”, Symposiumon Adv Functional Biomaterials, Proceedings of ICMAT, Singapore 2007
channel size and configuration while also reflecting the
microporosity along the sides of the channel. Fig 4c
shows an exploded view of the slice depicting the
microporosity distribution critical for the scaffold. ThePhaseEnhancedTM optics, significant increase in contrast is realized,
making it possible to image inherently low contrast samples such as
cartilage and biomaterials without contrast agents.
on Adv Functional Biomaterials, Proceedings of ICMAT, Singapore 2007[2] S H Lau, et al., : Rapid Virtual Histology in 3D for Cartilage, Soft tissue, Bones, Scaffolds and Cells with a novel micro and nano CT without contrast agents”, Paper # 10, 6TH Combined Meeting, Orthopedic Research Society 2007
microporosity distribution critical for the scaffold. The
ideal architecture desired for a scaffold with about 70-80
% space (pores and channels) and microarchitecture in
terms of size distribution is clearly seen from the CTterms of size distribution is clearly seen from the CT
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