Setting up the 3D finite element (FE) model on the basis of medical images is a necessary method of biomechanical analysis. The pretreatment, including data processing of images and mesh generation, becomes the bottleneck of FE analysis, and this is especially the case of the modeling for thoracic vertebrae, because the shapes and data are complicated. In this paper, on the basis of the data for building a 3D FE model of thoracic vertebrae, we present some structures and types of data which are essential for the reconstruction of CT medical image, analyze some methods for obtaining and processing the data from images, and then advance a theory for data management based on mesh generation by block with the software MSC. Marc. A 3D-FE Model of T10-T12 thoracic vertebrae is set up, which keeps the configuration of the true one, and satisfies the requirements of biomechanical analysis. We focus affention on the data obtainment and management during medical image processing and FE modeling, all of which are very important for the biomechanical analysis. It is helpful and instructive to reconstruct some similar tissues of human body on the basis of the medical images from CT, MRI, etc.
Biomechanical Phenomena ; Finite Element Analysis ; Humans ; Image Processing, Computer-Assisted ; Imaging, Three-Dimensional ; Models, Anatomic ; Thoracic Vertebrae ; diagnostic imaging ; Tomography, X-Ray Computed

A finite element model of human mandible is developed from CT scan images by the technologies of three-dimensional reconstruction, image processing and meshing. The mandible model is connected to one modified head model of Hybrid III dummy with joint according to the anatomic structure and mechanical characteristics of the temporomandibular joint. Then a finite element model of the human head with the true anatomic structure mandible is developed. This model has been validated with the cadaver test results. It can be used in researches on the mechanism of craniofacial blunt-impact injury and on the assessment of injury severity.
Biomechanical Phenomena ; Craniocerebral Trauma ; Finite Element Analysis ; Head ; anatomy & histology ; Humans ; Image Processing, Computer-Assisted ; Imaging, Three-Dimensional ; Mandible ; anatomy & histology ; Models, Anatomic ; Tomography, Spiral Computed

OBJECTIVE: To assess the association of genomic instability of epithelial cadherin 1 (CDH1) gene and clinicopathological characteristics of gastric cancer. METHODS: In total 120 paraffin-embedded gastric cancer tissue specimen were prepared, and genomic DNA was extracted. The genomic instability of the CDH1 gene was analyzed by immunohistochemistry and silver staining PCR-single-strand conformation polymorphism. RESULTS: The number of information individuals (heterozygotes) was 98 for the D16S752 locus. The detection rates for microsatellite instability (MSI) and loss of heterozygosity (LOH) at the D16S752 locus and the positive rate of CDH1 protein were 19.39%, 16.33% and 51.02%, respectively. The detection rate of MSI in TNM stages I or II was significantly higher than that in stages III or IV (P<0.05) while the detection rate of LOH was significantly lower than that in stages III or IV (P<0.05). The positive rate of CDH1 protein in TNM stages III or IV was significantly lower than that in stages I or II (P<0.05). The detection rate of MSI of cases with lymph node metastasis was significantly lower than that of without lymph node metastasis (P<0.05) while the detection rate of LOH was significantly higher than that without lymph node metastasis (P<0.05). The positive rate of CDH1 protein in patients with lymph node metastasis was significantly lower than that in patients without lymph node metastasis (P<0.05). The positive rate of CDH1 protein in MSI-positive group was significantly higher than that in MSI-negative group (P<0.05), and the positive rate of CDH1 protein in the LOH-positive group was significantly lower than that the LOH-negative group (P<0.05). CONCLUSION The genomic instability of the CDH1 gene is associated with the progression of gastric cancer. MSI at the D16S752 locus may be used as a molecular marker for early gastric cancer, while LOH at this locus mostly occurs in advanced gastric cancer and can be regarded as an effective indicators for malignancy evaluation and prognosis.
Humans ; Stomach Neoplasms/pathology* ; Lymphatic Metastasis ; Cdh1 Proteins/genetics* ; Microsatellite Instability ; Loss of Heterozygosity ; Genomic Instability ; Microsatellite Repeats ; Antigens, CD/genetics* ; Cadherins/genetics*