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Results for entries tagged with "Orthopedic

Histological Bone Morphometry

Traditional 2D bone morphometric analyses utilize hard-tissue histological sectioning and evaluation of bone cores (human or animal) stained with Toluidine Blue and embedded in PMMA.

Large field-of-view Analysis of Fracture Callus Healing

In order to assess the extent of healing following non-union fracture in response to various therapies (PTH, bisphosphonates, etc), the callus sites of histologically stained (i.e. Safranin-O/FAST Green) and sectioned long bones can be digitized using a high resolution, large field-of-view microscope and subsequently evaluated for thickness, area, and tissue composition (fibrous, bone, cartilagenous tissue content) in a quati.

Cellular Particle Exclusion Assay

Cellular matrix production is crucial in the formation, maintenance, and repair of organs and tissues. While there are many dyes and antibodies available to study matrix production in-vitro, such reporters can generally only be applied as an endpoint tool as they require cell fixation and do not support live cell study.

Colony Analysis

Undifferentiated embryonic stem cells and induced pluripotent stem cells will form aggregates or "colonies" in vitro prior to differentiation. Evaluation of colony shape, area, cell density, rate of growth/proliferation, migration, etc. can be important factors in selection of an appropriate cells for subsequent differentiation and expansion for transplantation or bioassay development.

Fracture Union Analysis

Non-union fractures can heal in an amorphous fashion and are thus difficult to assess qualitatively with regard to bridging success. Leveraging the 3D output of micro-computed tomography (CT) and subsequent image analysis, it is however possible to quantitatively represent bridging or union in a more consistent and logical manner that accounts for the non-uniformity in healing.

Bright Field Immuno-Staining

Non-fluorescent, immuno-staining of histological tissue for specific antigens generally involves enzymatic subtrates that oxidize compounds such as diaminobenzidine (DAB) to precipitate a brown chromogenic product. Unfortunately, "brown" color is composed of a mixture of hues not easily segmented or characterized from background.

Osseointegration of Bone Graft Analysis in CT

Assessment of bone growth into scaffolds or grafts is generally performed qualitatively and thus difficult to consistently replicate across timepoints for a given patient or across multiple patients. This is especially true when CT imaging protocols (resolution, tube potential/current, etc) aren't kept consistent.

Longitudinal Assessment of Fracture Healing

To evaluate efficacy of various treatments on fracture healing, a 1 mm fibular osteotomy was surgically created in rat fibulas. Micro-CT imaging sessions were performed (6 time-points across 36 days) to assess temporal changes in fracture healing. These time-points were spatially registered using a customized software package utilizing mutual information and iterative closest point algorithms.

Multi-modality Volumetric Registration

Spatial registration of longitudinal volumes and subsequent analysis can enable morphometric tracking of implants to evaluate degradation/biocompatibility or assess response of various pathologies/phenotypes to therapeutics or genetic manipulation.

Osseointegration of Bone Scaffolds in a Canine Defect Model

The canine femoral multi-defect model enables evaluation of bone in-growth within 4 separate defects placed > 1.5 cm apart in the proximal femur. For this model, animals are euthanized 4 weeks following implantation and bone scaffolds inserted into the surgically created cylindrical defects (1.0 cm diameter, 1.5 cm deep) are explanted and imaged using micro-computed tomography (CT).

Osseointegration in Bone Substitutes

To determine efficacy of candidate bone substitutes for non-weight bearing applications such as facial reconstruction, rate and extent of osseointegration or mineralization are key assessment parameters. Unfortunately traditional means of evaluation require multiple animals to be sacrificed at each time point followed by exhaustive histological sectioning, staining, imaging and quantitative analysis for bone in-growth for the duration of the study.

Osseointegration of Titanium Bone Screws

To assess the effects of implant surface contaminants on osseointegration, titanium bone screws with variable degrees of cleaning were implanted into the mid-diaphysis of a mouse femur for 5 weeks, explanted and imaged using micro-CT. Subsequent customized image analysis using spectral and morphological filters enabled generation of 3D screw masks.

Micro-Computed Tomography (CT) Evaluation of Cartilage Profile using the Contrast Agent Conray

Evaluation of articular cartilage defects or delamination in small animal models for assessment of repair or response to pharmaceuticals requires both high spatial and density resolution. Unfortunately while small animal MRI systems will allow visualization cartilage, resolution is poor. While micro-computed tomography will provide the necessary resolution (as high as 1 um), soft tissue interfaces like cartilage do not attenuate well and thus are not generally visible or extremely noisy at best.

Skull Mapping

To determine if disruption of specific signaling pathways can effect mineralization of cranial bones, volumetric and density measurement is required for each of the bones in the calvaria of genetically modified, embryonic mice. To accomplish this, skulls of E18 mice were scanned using micro-computed tomography (micro-CT).

Trabecular Analysis of Rat Vertebrae

Although not loaded in the same manner as humans, vertebrae in small animals can be used to study structural changes in trabecular bone in response to various drugs and therapies for the treatment of osteoporosis if appropriate controls are in place.

Analysis of Spinal Curvature

Micro-Computed tomography (micro-CT) scans of the vertebrae from knock-out mice were analyzed to determine degree of spinal curvature or kyphosis.

Trabecular Analysis on Human Bone Cores

Trabecular bone quality assessment is generally not performed in patient CT scans due to inadequate resolution, however, bone cores may be extracted from patients in non-weight bearing sites (i.e. illiac crest) or from discards obtained during implant insertion and scanned using micro-computed tomography (micro-CT) for analysis of structural indices.

Trabecular Analysis on Rat/Mouse Proximal Tibias

Trabecular bone quality metrics are commonly extracted from long bones and vertebrae of ovariectomized small animal models (induces osteoporosis in mice and rats) to evaluate effectiveness of various pharmaceuticals or gene therapies in counteracting osteoporosis induced bone loss.

Cell Proliferation/Lineage Analysis

Cellular division and lineage tracing analysis is an extremely complex problem with respect to image analysis but essential for cell fate assessment and phenotyping following genetic manipulation or drug treatment.

Tube Formation Analysis

Endothelial cells (EC), when provided with a 3D extracellular matrix substrate and appropriately supplemented growth media, will self-organize into a network of capillary-like "tubes." This in-vitro, "tube formation" assay, is commonly used to assess ability of compounds to stimulate or inhibit angiogenesis.

Automated Histological Analysis of Cartilage Defects

Sports-related injuries can produce large focal defects in articular joint cartilage that often lead to delamination of surrounding healthy cartilage and eventual degeneration of the joint. To study this process in an animal model, a pendulum was swung onto the medial condyles of a rabbit femur. After a predefined length of time, the rabbit was sacrificed and the impact region was explanted, sectioned, and stained with Safranin-O.

Automated Histological Analysis of Osseointegration

The structure and chemical composition of bone scaffolds or implants will impact their ability to promote bone in-growth and consequently dictate stability of the implant. Small animal models are often utilized for evaluation of bone in-growth in candidate scaffolds. Scaffolds are generally implanted into proximal sites of long bones for a fixed period of time.

In-vivo Histological Bone Growth Assay

Traditional methods of in-vivo bone growth evaluation in small animal models utilize longitudinal micro-CT imaging. Unfortunately, live animal imaging requires low radiation dose protocols that limit spatial resolution to ~20 um which is inadequate for small animals (particularly adults) whose bone growth rates are on the order of a few um/day.

Custom Software Development for Total Shoulder Replacement Surgery

Traditional tools for shoulder arthroplasty planning include evaluation of 2D x-ray micrographs, 3D CT volumes and/or MRI volumes in the operating room for estimation of glenoid vault dimensions and available mass for implant fixation

Adipocyte Characterization

Morphometric analysis of fat cells or adipocytes within specific organs enables quantitative assessment of various pathologies or compounds that affect metabolic pathways. Unfortunately, most labs will perform such analysis with multiple observers manually delineating each adipocyte in a given field-of-view.

3D Vascular Analysis

Contrast based vascular imaging and analysis can provide an number of key metrics for human pathology diagnosis or animal model studies including vessel occlusion, blood pressure (vessel dilation), angiogenesis (tumor formation), vascular attenuation or regression, and vascular leakage.

TEM Collagen Fibril Morphometry

Transmission electron microscopy (TEM) is a valuable imaging tool for nanometer scale assessment of extracellular matrix organization and localization/morphology of subcellular structures. As an example, collagen fibrils in a genetically modified animal model were imaged using TEM for evaluation of collagen morphology and spacing/packing.

Scaffold/Implant Quality Assessment

Evaluation of devices pre and post implantation can be extremely valuable for assessing wear and degradation or just as a means of quality assurance. This is particularly important for biological scaffolds that have variable geometries post-fabrication. For such an assessment to be valuable, especially for samples evaluated pre-implantation, the imaging modality utilized has to be non-destructive and conducted in a sterile environment.

Osseointegration of Resorbable ACL Screws

Bioresorbable interference screws are theorized to fill in with bone tissue over time as they dissolve, but still provide the same initial anchoring support for the ACL as traditional metal screws. Potentially, such an implant could delay/eliminate revisions related to loosening that is observed with metallic implants.

Cartilage Thickness in CT Arthrograms

CT arthrograms involve injection of a contrast agent into joint spaces prior to scanning to study abnormalities or tears in articulating surfaces (cartilage), tendons, ligaments, or the joint capsule as a result of injury, osteoarthritis, or other pathology. Additionally, joint contrast will clearly delineate boundaries of soft tissue that generally is weakly attenuating and noisy.