Hemodynamic Analysis on Anomalous Origin of the Right Coronary Artery from the Left Coronary Artery Sinus / 医用生物力学

Objective To analyze the hemodynamic parameters of anomalous origin of the right coronary artery from the left coronary artery sinus (AORL) based on computational fluid dynamics (CFD), so as to make an evaluation of the disease. Methods A normal right coronary artery (RCA) case and an AORL case were selected. Two models were reconstructed in Mimics software and imported into ANSYS CFX software for hemodynamics simulation. The hemodynamics of normal RCA model and AORL model were compared. Results AORL model had a smaller volume flow (9.35 cm3/s), which might lead to insufficient blood supply downstream of the RCA; the pressure at the acute corner of AORL model (13.78 kPa) was lower than normal RCA model (14.9 kPa); the wall shear stress (WSS) of AORL model (12.83 Pa) was larger than that of normal RCA model (9.74 Pa); the total deformation of AORL model was relatively large. Conclusions The entrance velocity and pressure of AORL were lower than those of normal RCA, which might lead to ischemic symptoms. The research findings are of theoretical significance for the effective evaluation of ischemia and other diseases in clinic.

Three-dimensional reconstruction and finite element analysis of the optic nerve head of a cat / 中国组织工程研究

BACKGROUND: Glaucoma is a kind of eye disease that can cause irreversible blindness which is characterized by visual field loss. Clinical research shows that the optic nerve head has changed before the visual field loss. The morphological changes of the optic nerve head have become the key to determine the early diagnosis of glaucoma and disease development. So it has important significance for us to study the morphological changes of the tissues of optic nerve head under the high intraocular pressure. OBJECTIVE: To establish three-dimensional finite element model of optic nerve head which includes choroid, retina and lamina cribrosa, and analyze the thickness of the optic nerve head under the acute high intraocular pressure. METHODS: (1) We chose healthy cats without refractive media and other eye diseases. The tomographic sequence images of the optic nerve head of a cat were obtained with the intraocular pressure of the normal value by using enhanced depth imaging spectral-domain optical coherence tomography. (2) The three-dimensional model of the retina, choroid and lamina cribrosa was obtained. Three-dimensional model of optic nerve head was established by assembling the model of the retina, the choroid and the lamina cribrosa. The thickness of the retina, choroid and lamina cribrosa was analyzed under different intraocular pressures by using the method of finite element analysis. (3) Animal model of acute ocular hypertension was established by methods of anterior chamber perfusion. The tomographic sequence images of the optic nerve head of a cat were obtained with different intraocular pressures by using enhanced depth imaging spectral-domain optical coherence tomography. Then, we measured the thickness changes of the choroid, retina and lamina cribrosa under different intraocular pressures, and compared with the results of finite element analysis. RESULTS AND CONCLUSION: The thickness of the choroid, retina and lamina cribrosa trended to be thin, and the cup dish ratio of optic nerve head increased gradual y with the increased intraocular pressures. Regarding to the thickness changes of the choroid, retina and lamina cribrosa, the trend of experimental measurement results was consistent with finite element calculation results. Hence, it is feasible to analyze morphological changes of every fundus tissue under high intraocular pressure using the tomographic sequence images obtained by optical coherence tomography. We can predict the morphological changes of the optic nerve head tissue by finite element analysis, which has certain guiding significance in determining the progression of glaucoma.

Undergraduate Training Scheme for Prosthetic and Orthotics Engineering / 中国康复理论与实践

@#Capital Medical University has opened the courses of Prosthetic and Orthotics Engineering since 2003. Through a three-period development of more than ten years, the professional training scheme has met the international requirements and highlight in specialty characteristics. It needs a combination of medicine, rehabilitation, technology, prosthetic and orthotics, an enough foundation for personals and sites, teachers of bi-profession, and a comprehensive test system to practice.

Shape variation of optic nerve head by mechanical analysis using three-dimensional finite element model / 中国组织工程研究

BACKGROUND:The measure and prediction of the shape of optic nerve head are the key issues for early diagnosis and duration prediction of glaucoma. Therefore, it is significant to research the shape variation of optic nerve head under high intraocular pressure. OBJECTIVE:To establish three-dimensional finite element model of optic nerve head and to analyze the deformation of optic nerve head and the change in retina thickness after acute high intraocular pressure. METHODS:Animal model of acute ocular hypertension was established by methods of anterior chamber perfusion. The tomographic images of the optic nerve head of a cat were obtained at the normal intraocular pressure and 5 320 Pa, 7 980 Pa, 10 640 Pa, 13 300 Pa, 15 960 Pa intraocular pressures using optical coherence tomography. Then, we measured the variation of retinal thickness at typical location. Basing on the tomographic images of optic nerve head of a cat at normal intraocular pressure, we obtained three-dimensional structure of retina and choroid using software MIMICS. Then three-dimensional model of optic nerve head was established by assembling the retina and choroid. The deformation of optic nerve head and the change in retinal thickness under high intraocular pressure were observed using software ABAQUS. The effectiveness of the model was verified by the experimental result. RESULTS AND CONCLUSION:With the increase of intraocular pressure, the retinal thickness is thinner, the optic nerve head depth, width and the ratio of the depth to width are gradual y increased. It suggests that the acute high intraocular pressure causes retinal thinning, optic nerve head widening and deepening. It is feasible to establish optic nerve head modeling in vivo by using optical coherence tomography, mechanical analysis can be applied to predict the shape variation of optic nerve head, which is significant to further deduce the pathological process of glaucoma.