3D Printing based on the CT data of measured object can print out the outer surface structure and internal surface structure of the object and can be used for reverse engineering. This paper presents ...a frame for generating 3D printing data directly from CT data. The frame includes three steps: firstly, surface mesh data with internal structure is extracted from CT data. Secondly, a mesh model recognized by 3D printer is obtained through generating topological information, removing isolated facets and non-manifold facets, filling holes and smoothing surface. Thirdly, for the target surface mesh model with internal structure or exceeding the maximum size of objects that 3D printer can print, the frame splits the mesh model into several parts and print them separately. The proposed frame was evaluated with a simulated CT data and two real CT data. These experiments showed that the proposed frame is effective to generate 3D printing data directly from CT data and preserve the shape analogy with the original object model with high precision.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This work aimed to perform a detailed in vitro and in silico characterization of open-cell structures, which resemble trabecular bone, to elucidate osteoporosis failure mechanisms. Experimental and ...image-based computational methods were used to estimate Young′s modulus and porosities of different open-cell structures (Sawbones; Malmö, Sweden). Three different open-cell structures with different porosities were characterized. Additionally, some open-cell structures were scanned using a microcomputed tomography system (μCT) to non-destructively predict specimen Young′s modulus of the structures by developing voxel-based and tetrahedral finite element (FE) models. A 3D reconstruction and FE analyses were used. The experimental and computational results with different element types (linear and quadratic tetrahedrons and voxel-based meshes) were compared with Sawbones data (Sawbones; Malmö, Sweden) revealing important differences in Young′s modulus and porosities. The specimens with high and low volume fractions were best represented by linear and quadratic tetrahedrons, respectively. These results could be used to develop new osteoporosis-prevention strategies.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
The purpose of this research was to simulate mandibular movement calculated from three-dimensional computed tomography (CT) data to determine the linear distractor position to correct mandibular ...deformities in a series of patients with hemifacial microsomia (HFM). Preoperative CT scans from 6 HFM patients were obtained and imported into a CT-based software program (Mimics) to produce three-dimensional images and data. After measurement of the mandibular deficiency in 3 dimensions (horizontal and vertical), the angle between the distraction device and the ramus was determined by a geometric calculation, and then the surgery was performed on the three-dimensional model constructed using the rapid prototyping technique. This planning method was finally used in the treatment of 6 HFM patients. The HFM was corrected, and a symmetrical facial contour obtained without any complications in these 6 patients. The results matched the expectation before surgery that the distractor elongation would range from 18 to 22 mm. The distraction tracing model fitted the actual postdistraction tracing to within 2 mm. The preoperative design and three-dimensional modeling technique are considered to be helpful in enhancing the predictability and improving the outcome of the treatment of distraction osteogenesis.
Advanced additive manufacturing technologies, namely Biomanufacturing, are being used to fabricate scaffolds with controlled architecture for tissue engineering applications. These technologies ...combined with computer-aided design (CAD) enable to produce three-dimensional structures layer-by-layer in a multitude of biomaterials. Actual prediction of the effective mechanical properties of scaffolds produced by Biomanufacturing, is very important for tissue engineering applications. A novel computer based technique for scaffold design is topological optimisation. Topological optimisation is a form of “shape” optimisation, usually referred to as “layout” optimisation. The goal of topological optimisation is to find the best use of material for a body that is subjected to either a single load or a multiple load distribution. In this research work, a topological optimization strategy is presented to find out the best material use for a construct subject to either a single load or a multiple load distribution, maximising its mechanical behaviour under tensile and shear stress solicitations. The proposed topological optimization scheme enables the design of ideal topological architectures based on existing biologic Micro-CT data for the design of biomimetic scaffolds.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Background: Reconstruction of malunited diaphyseal fractures of the forearm is one of the most difficult treatments due to its complicated structure. Widespread usage of Digital Imaging and ...Communications in Medicine (DICOM) data of 3-dimensional (3D) computed tomography (CT) and 3D printing can make estimating the true plane of the deformity easy. Methods: A 21-year-old man with limited supination due to left forearm nonunion deformity initially treated by locking plate fixation was referred to our hospital. We evaluated the deformity by superimposing the mirror image bone model of the contralateral normal bone onto a model of the affected bone and 3D real full-scale bone model. Results: The patient underwent a manual corrective osteotomy according to our planning. He had satisfactory improvement of his symptoms with no complications. Conclusions: We postulated that our simple preoperative simulation and manual osteotomy with the aid of 3D CT reconstruction and 3D real full-scale bone model fit in the clinical practice as a recent trend.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
The research emphasis on the development of Finite Element (FE) model of the human middle ear (ME) that comprises of the tympanic membrane (TM), three auditory ossicles, various ligament structures, ...and muscles. Due to the complex geometrical shape, conventional modeling techniques leads to inaccuracy in model morphology. A widely held approach to model such complex biological components is by using micro X-ray computed tomography (μCT). High-resolution 3-Dimensional morphology models of the human ME are published and made available for non-commercial research purpose, but these published models are in form of surface meshes and holds good for visualization purpose and 3-D printing only. To simulate and analyze the dynamic behavior of ME components it is essential to convert these surface meshes (stereolithography files) into volume meshes and hence these geometrical models necessitate further processing. Additionally, an attempt has been made to design and incorporate certain missing geometries to represent a complete ME model. The intent of current study is to develop a resourceful anatomically precise FE model of the human ME which is capable of incorporating variation in parameters and corresponds in view of that.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Subject-specific finite element models are an extensively used tool for the numerical analysis of the biomechanical behaviour of human bones. However, bone modelling is not an easy task due to the ...complex behaviour of bone tissue, involving non-homogeneous and anisotropic mechanical properties. Moreover, bone is a living tissue and therefore its microstructure and mechanical properties evolve with time in a known process called bone remodelling. This phenomenon has been widely studied, many being the numerical models that have been formulated to predict density distribution and its evolution in several bones. The aim of the present study is to assess the capability of a bone remodelling model to predict the bone density distribution of different types of human bone (femur, tibia and mandible) comparing the obtained results with the bone density estimated by means of computerised tomography. Good accuracy was observed for the bone remodelling predictions including the thickness of the cortical layer.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Pulmonary interlobar fissures are important anatomic structures in human lungs and are useful in locating and classifying lung abnormalities. Automatic segmentation of fissures is a difficult task ...because of their low contrast and large variability. We developed a fully automatic training-free approach for fissure segmentation based on the local bending degree (LBD) and the maximum bending index (MBI). The LBD is determined by the angle between the eigenvectors of two Hessian matrices for a pair of adjacent voxels. It is used to construct a constraint to extract the candidate surfaces in three-dimensional (3D) space. The MBI is a measure to discriminate cylindrical surfaces from planar surfaces in 3D space. Our approach for segmenting fissures consists of five steps, including lung segmentation, plane-like structure enhancement, surface extraction with LBD, initial fissure identification with MBI, and fissure extension based on local plane fitting. When applying our approach to 15 chest computed tomography (CT) scans, the mean values of the positive predictive value, the sensitivity, the root–mean square (RMS) distance, and the maximal RMS are 91 %, 88 %, 1.01 ± 0.99 mm, and 11.56 mm, respectively, which suggests that our algorithm can efficiently segment fissures in chest CT scans.
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NUK, OBVAL, SBMB, SBNM, UL, UM, UPUK, VSZLJ
We describe the braincase of AMNH FR 21444, a gecko-like squamate from the Early Cretaceous of Mongolia, based on high-resolution X-ray computed tomography scans (CT scans) and incorporate it in a ...phylogenetic analysis of 36 squamate taxa scored for 226 morphological characters. Our analysis corroborates the Eublepharidae-Gekkonoidea split as the basal gekkotan dichotomy, but retrieves Teratoscincus as the sister-taxon to pygopodines + diplodactylines. The combination of plesiomorphic and apomorphic character states within AMNH FR 21444 demonstrates a decoupled evolutionary history between the braincase and the rest of the skull and mandible within gekkonomorph squamates. Enclosure of the lateral head vein and mandibular branch of the trigeminal nerve are both plesiomorphic for gekkonomorphs. The mechanisms responsible for the transition from the plesiomorphic skull roof of basal gekkonomorphs to the modern gekkotan condition cannot be anticipated given the current data.
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BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Current surgical treatment planning systems predict three-dimensional (3D) corrections from two-dimensional (2D) data and are inadequate for complex movements. In this paper, we present a 3D planning ...system based on computed tomographic (CT) data.
A three-dimensional CT scan of the craniofacial skeleton forms the database. Software developed in the Harvard Surgical Planning Laboratory was modified for the craniofacial skeleton. Reproducible skeletal landmarks are identified for superimposition. A ‘cutting tool’ is used to segment the mandible and segments are moved to their predicted positions. A ‘collision tool’, alerts the operator of skeletal interferences. An analysis of selected scans is used to demonstrate the system.
Three-dimensional visualization of the facial skeleton, selection of landmarks, measurement of angles and distances, simulation of osteotomies, repositioning of bones, detection of collisions and super-imposition of scans were accomplished.
In an illustrative case of Hemifacial Microsomia, predicted and actual 3D corrective movements of the entire mandible were documented. Analysis of scans indicated that 3D planning can prevent insufficient jaw lengthening or other surgical inaccuracies which occur with standard 2D methods.
Software demonstrated here will allow the surgeon to accurately plan treatment and evaluate craniomaxillofacial surgery outcomes. Future applications may include surgical navigation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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