A Three‐Dimensional Atlas of Human Tongue Muscles

The human tongue is one of the most important yet least understood structures of the body. One reason for the relative lack of research on the human tongue is its complex anatomy. This is a real barrier to investigators as there are few anatomical resources in the literature that show this complex anatomy clearly. As a result, the diagnosis and treatment of tongue disorders lags behind that for other structures of the head and neck. This report intended to fill this gap by displaying the tongue's anatomy in multiple ways. The primary material used in this study was serial axial images of the male and female human tongue from the Visible Human (VH) Project of the National Library of Medicine. In addition, thick serial coronal sections of three human tongues were rendered translucent. The VH axial images were computer reconstructed into serial coronal sections and each tongue muscle was outlined. These outlines were used to construct a three‐dimensional (3D) computer model of the tongue that allows each muscle to be seen in its in vivo anatomical position. The thick coronal sections supplement the 3D model by showing details of the complex interweaving of tongue muscles throughout the tongue. The graphics are perhaps the clearest guide to date to aid clinical or basic science investigators in identifying each tongue muscle in any part of the human tongue. Anat Rec, 296:1102–1114, 2013. © 2013 Wiley Periodicals, Inc.     

消融导管三维定位导航系统中心脏多腔模型的构建

背景：目前,心内膜三维标测系统的研制是国内外医学工程学界的一个热点。国外已经推出了适用于临床的系统,但是其价格极其昂贵;国内还只是处于研究阶段,因此,在心内膜三维标测系统的国产化方面任重道远。 目的：采集分析消融导管三维定位导航系统的建模数据,并重构心内膜三维几何模型。 方法：心内膜三维建模数据的采集直接关系到建模质量的高低。以离散点的形式将数据采集过程进行可视化,可获得全面和有效的建模数据点集;通过对所得的点云数据进行凸包运算,获取数据集的表面极值点,构造用边界表示的多面体模型;最后以生成的多面体为基本体素,采用离散法造型完成建模过程。并使用可视化类库VTK,成功的重构了心内膜三维模型。 结果与结论：仿真实验表明,实验提出的方法可以较全面、高效地采集建模数据,重构心内膜三维模型。提示重构的心内膜三维几何模型可以为消融导管三维定位导航系统提供技术支持。     

Predictive statistical models of baseline variations in 3-D femoral cortex morphology

Quantifying human femoral cortex morphology is important for forensic science, surgical planning, prosthesis design and musculoskeletal modeling. Previous studies have been restricted by traditional zero or one dimensional morphometric measurements at discrete locations. We have used automatic image segmentation and statistical shape modeling methods to create predictive models of baseline 3-D femoral cortex morphology on a statistically significant population. A total of 204 femurs were automatically segmented and measured to obtain 3-D shape, whole-surface cortical thickness, and morphometric measurements. Principal components of shape and cortical thickness were correlated to anthropological data (age, sex, height and body mass) to produce predictive statistical models. We show that predictions of an individual's age, height, and sex can be improved by using 3-D shape and cortical thickness when compared with traditional morphometric measurements. We also show that femoral cortex geometry can be predicted from anthropological data combined with femoral measurements with less than 2.3 mm root mean square error, and cortical thickness with less than 0.5 mm root mean square error. The predictive models presented offer new ways to infer subject-specific 3-D femur morphology from sparse subject data for biomechanical simulations, and inversely infer subject data from femur morphology for anthropological and forensic studies.     

Analysis of human lung morphometric data for stochastic aerosol deposition calculations

A stochastic lung model is proposed for aerosol deposition calculations. Airway geometry is selected randomly to reflect intrasubject variations in the human airway system. This may also be adjusted to take intersubject variations into account. The statistical analysis of the human airway geometry used is based on morphometric data measured at the Lovelace Inhalation Toxicology Research Institute. Average values and distributions of airway diameters and lengths, distributions of branching angles and criteria for termination of the pathway (when the alveolar region is reached) are presented. Correlations between the cross sections of tubes of succeeding generations and those between diameters and lengths of the same generation are also given.     

Large-Scale 3-D Geometric Reconstruction of the Porcine Coronary Arterial Vasculature Based on Detailed Anatomical Data

The temporal and spatial distribution of coronary blood flow, pressure, and volume are determined by the branching pattern and three-dimensional (3-D) geometry of the coronary vasculature, and by the mechanics of heart wall and vascular tone. Consequently, a realistic simulation of coronary blood flow requires, as a first step, an accurate representation of the coronary vasculature in a 3-D model of the beating heart. In the present study, a large-scale stochastic reconstruction of the asymmetric coronary arterial trees (right coronary artery, RCA; left anterior descending, LAD; and left circumflex, LCx) of the porcine heart has been carried out to set the stage for future hemodynamic analysis. The model spans the entire coronary arterial tree down to the capillary vessels. The 3-D tree structure was reconstructed initially in rectangular slab geometry by means of global geometrical optimization using parallel simulated annealing (SA) algorithm. The SA optimization was subject to constraints prescribed by previously measured morphometric features of the coronary arterial trees. Subsequently, the reconstructed trees were mapped onto a prolate spheroid geometry of the heart. The transformed geometry was determined through least squares minimization of the related changes in both segments lengths and their angular characteristics. Vessel diameters were assigned based on a novel representation of diameter asymmetry along bifurcations. The reconstructed RCA, LAD and LCx arterial trees show qualitative resemblance to native coronary networks, and their morphological statistics are consistent with the measured data. The present model constitutes the first most extensive reconstruction of the entire coronary arterial system which will serve as a geometric foundation for future studies of flow in an anatomically accurate 3-D coronary vascular model.     

Comparative morphometry of the upper bronchial tree in six mammalian species

The length, diameter, and angle of branching of all airways through the sixth level of branching below the trachea were measured on corrosion casts prepared from the lungs of two animals whose bronchial geometry has not previously been studied, namely the donkey and the rabbit. These measurements and morphometric data for the rat, hamster, dog, and human obtained from other sources were analyzed and compared. The cast prepared from human lungs exhibited an airway geometry that was clearly distinct from that shown by the nonhuman species. The human upper bronchial tree was the most symmetrical with respect to airway diameter and angle of branching. In all species studied, airway length was the most irregular parameter. The reasons for differences in branching geometry are not clearly understood. However, when attempting to determine whether a particular species may be used as a model for man in inhalation toxicology, and in the subsequent interpretation of animal data, an appreciation of differences in airway morphometry is essential.     

可视人体(VH)数据集及使用

可视人体工程是美国ＮＬＭ１９８６年长期规划的产物。该规划的目标是建立一个完整的,解剖详细的,三维的男体及女体表地。本文将对ＶＨＰ及其意义,数据的获得取及使用方法估和简要的介绍。     

Developing integrative computational models of pulmonary structure

Integrative computational modeling of the pulmonary system aims to incorporate interactions between the lung's subsystems by means of a hierarchy of structural and functional models. This requires detailed imaging-based data, along with a wide range of functional information from experiments. Advances in computed tomography imaging technology ensure that high-resolution data are now readily available upon which the structure of these models can be based. We present methods for constructing anatomically realistic finite element models of interrelated pulmonary structures from such data. Segmented human lung lobe data are fit to high-order (cubic Hermite) volume elements. Meshes for the conducting airways and pulmonary arteries and veins are constructed within the lobe mesh, using a combination of fitting to imaging data and a bifurcating-distributive algorithm. The algorithm generates an airway-consistent mesh within a host volume, and this airway mesh is then used as a template for generating blood vessel models. The lung parenchyma is modeled as a space-filling three-dimensional (3D) Voronoi mesh, with generated geometry consistent with the alveolated airway structure. Pulmonary capillaries are generated over the alveolar model, as a 2D Voronoi mesh. These structural models have been compared extensively with morphometric data to verify that their geometry is representative of the pulmonary system. The models are designed to be integrative: they relate multiple structural systems within the same individual, and their use as computational meshes allows application of spatially distributed properties.     

Modeling the pharyngeal anatomical effects on breathing resistance and aerodynamically generated sound

The objective of this study was to systematically assess the effects of pharyngeal anatomical details on breathing resistance and acoustic characteristics by means of computational modeling. A physiologically realistic nose-throat airway was reconstructed from medical images. Individual airway anatomy such as the uvula, pharynx, and larynx was then isolated for examination by gradually simplifying this image-based model geometry. Large eddy simulations with the FW-H acoustics model were used to simulate airflows and acoustic sound generation with constant flow inhalations in rigid-walled airway geometries. Results showed that pharyngeal anatomical details exerted a significant impact on breathing resistance and energy distribution of acoustic sound. The uvula constriction induced considerably increased levels of pressure drop and acoustic power in the pharynx, which could start and worsen snoring symptoms. Each source anatomy was observed to generate a unique spectrum with signature peak frequencies and energy distribution. Moreover, severe pharyngeal airway narrowing led to an upward shift of sound energy in the high-frequency range. Results indicated that computational aeroacoustic modeling appeared to be a practical tool to study breathing-related disorders. Specifically, high-frequency acoustic signals might disclose additional clues to the mechanism of apneic snoring and should be included in future acoustic studies.     

An Anatomically Based Hybrid Computational Model of the Human Lung and its Application to Low Frequency Oscillatory Mechanics

Lung input impedance measured via forced oscillation over low frequency range has been confirmed as sensitive to the degree and the heterogeneity of lung disease. In this study we advanced an image-based, multi-scale computational model for the human lung, which includes upper and central airways, small airways and alveoli tissue unit. A three-dimensional (3-D) realistic model of the upper airway (reconstructed from MRI images) was combined with an anatomically based 3-D model of the central airways (based on MDCT images) to form a 3-D model of the large airways (from mouth to generation 6, incomplete for generations 4–6). The small airway trees distal to the central branches were based on a hypothetical airway tree for a normal healthy lung. A constant phase viscoelastic model was assumed for the alveolar tissue unit. Unsteady airflows in the large airways were simulated based on computational fluid dynamics (CFD). An experimentally measured broadband forcing flow was applied at the mouth. The impedance of the small airways was computed based on a one-dimensional transmission line model. The computed overall dynamic lung resistance and elastance compared very well with experimental values. Results showed that unsteady 3-D simulation and realistic geometry of the upper and large airways up to generations 4–6 can provide a reasonably accurate estimation of lung input impedance. The impedance of the upper airway constitutes a significant part of the total lung input impedance. The resistance of the upper airway accounts for 45–70% of the total lung resistance at frequencies between 0 and 1 Hz, and 70–81% at frequencies between 1 and 8 Hz.     

The pre-styloid compartment of the parapharyngeal space: a three-dimensional digitized model based on the Chinese Visible Human

To build a digitized visible model of the parapharyngeal space of the Chinese Visible Human and to provide a sectional anatomic basis for radiological and clinical diagnosis of the parapharyngeal space, sectional anatomy data of the parapharyngeal space were selected from the Chinese Visible Human male and female to compare with MR imaging findings in the axial planes. From these data the parapharyngeal space and surrounding structures were segmented. They were then reconstructed in three dimensions on PC. In the axial planes of the sectional anatomy and MR imaging, the shape, content and relations of the parapharyngeal space were clearly displayed and the dominant plane for showing the parapharyngeal space was elicited. The three-dimensional reconstructed images displayed perfectly the anatomic relationships of the parapharyngeal space, parotid, muscles, mandible and vessels. All reconstructed structures can be displayed singly, in groups or as a whole; any diameter or angle of the reconstructed structures can be easily measured. The Chinese Visible Human male and female data set can provide complete and accurate data. The digitized model of the parapharyngeal space and its surroundings offers unique insights into the complex anatomy of the area, providing morphologic data for imaging diagnosis and surgery of the parapharyngeal space.Grant sponsor: National Science Fund of China (NSFC)Grant number: 30270698, 60373112     

仿真环境下医学器官的三维有限元建模方法

背景：通过医学影像图片数据进行三维重建的模型主要应用于医学临床分析,而采用激光扫描进行逆向重建时建立的模型主要用于生物力学分析。生物力学模型建立的精确程度,直接影响分析结果。 目的：分析采用医学影像图片数据和三维激光扫描重建医学器官模型的两种方法及意义。 方法：①通过人体CT断层扫描医学影像图片数据,并运用医学重建软件进行三维重建。②采用三维激光扫描仪对医学模型进行扫描得到点云数据,再利用逆向处理软件实现医学器官模型的逆向重建。 结果与结论：两种方法都可以建立符合人体解剖结构、可进行生物力学仿真计算的几何模型和有限元模型。医学影像CT/MRI数据重建的三维模型,能够真实再现被扫描对象的表面特征及内部结构,该模型为临床辅助诊断、手术规划、整形、假肢设计及解剖教学等方面提供了可靠的参考模型。三维激光扫描所得点云数据进行逆向重建,具有测量精度高、速度快,能够反映所测标本的表面形态,该模型可在交通运输、军事领域中因发生钝性冲击对人体内部器官造成的损伤进行计算机仿真分析。     

Human Movement Reconstruction from Video Shot by a Single Stationary Camera

One of the key techniques in the research of human motion analysis is the reconstruction of human spatial motion, which utilizes the anatomic points positions that can uniquely define the position and orientation of all anatomical segments. In this paper, upon the basis of Direct Linear Transform (DLT) and a human biomechanical model, the method to reconstruct human motion from an image sequence shot by a single stationary camera was described. In this method, the Lagrange Multiplier Method was used to minimize the difference between the actual and reconstructed length of limbs. This approach here is more comprehensive than previous methods that utilized cost functions to select results from feasible solutions. To examine this method, a practical human motion measured by a motion analysis system was selected and reconstructed. The spatial positions of joints were predicted with an average R² of 0.9722 and mean residual error of 0.0022 m. This approach presented here provides a simple way to reconstruct the human spatial motion only utilizing a single camera.     

Anatomical Details of the Rabbit Nasal Passages and Their Implications in Breathing,Air Conditioning,and Olfaction

The rabbit is commonly used as a laboratory animal for inhalation toxicology tests and detail knowledge of the rabbit airway morphometry is needed for outcome analysis or theoretical modeling. The objective of this study is to quantify the morphometric dimension of the nasal airway of a New Zealand white rabbit and to relate the morphology and functions through analytical and computational methods. Images of high‐resolution MRI scans of the rabbit were processed to measure the axial distribution of the cross‐sectional areas, perimeter, and complexity level. The lateral recess, which has functions other than respiration or olfaction, was isolated from the nasal airway and its dimension was quantified separately. A low Reynolds number turbulence model was implemented to simulate the airflow, heat transfer, vapor transport, and wall shear stress. Results of this study provide detailed morphological information of the rabbit that can be used in the studies of olfaction, inhalation toxicology, drug delivery, and physiology‐based pharmacokinetics modeling. For the first time, we reported a spiral nasal vestibule that splits into three paths leading to the dorsal meatus, maxilloturbinate, and ventral meatus, respectively. Both non‐dimensional functional analysis and CFD simulations suggested that the airflow in the rabbit nose is laminar and the unsteady effect is only significantly during sniffing. Due to the large surface‐to‐volume ratio, the maxilloturbinate is highly effective in warming and moistening the inhaled air to body conditions. The unique anatomical structure and respiratory airflow pattern may have important implications for designing new odorant detectors or electronic noses. Anat Rec, 299:853–868, 2016. © 2016 Wiley Periodicals, Inc.     

3D geometry analysis of the medial meniscus – a statistical shape modeling approach

The geometry‐dependent functioning of the meniscus indicates that detailed knowledge on 3D meniscus geometry and its inter‐subject variation is essential to design well functioning anatomically shaped meniscus replacements. Therefore, the aim of this study was to quantify 3D meniscus geometry and to determine whether variation in medial meniscus geometry is size‐ or shape‐driven. Also we performed a cluster analysis to identify distinct morphological groups of medial menisci and assessed whether meniscal geometry is gender‐dependent. A statistical shape model was created, containing the meniscus geometries of 35 subjects (20 females, 15 males) that were obtained from MR images. A principal component analysis was performed to determine the most important modes of geometry variation and the characteristic changes per principal component were evaluated. Each meniscus from the original dataset was then reconstructed as a linear combination of principal components. This allowed the comparison of male and female menisci, and a cluster analysis to determine distinct morphological meniscus groups. Of the variation in medial meniscus geometry, 53.8% was found to be due to primarily size‐related differences and 29.6% due to shape differences. Shape changes were most prominent in the cross‐sectional plane, rather than in the transverse plane. Significant differences between male and female menisci were only found for principal component 1, which predominantly reflected size differences. The cluster analysis resulted in four clusters, yet these clusters represented two statistically different meniscal shapes, as differences between cluster 1, 2 and 4 were only present for principal component 1. This study illustrates that differences in meniscal geometry cannot be explained by scaling only, but that different meniscal shapes can be distinguished. Functional analysis, e.g. through finite element modeling, is required to assess whether these distinct shapes actually influence the biomechanical performance of the meniscus.     

Airway Morphology From High Resolution Computed Tomography in Healthy Subjects and Patients With Moderate Persistent Asthma

Models of the human respiratory tract developed in the past were based on measurements made on human tracheobronchial airways of healthy subjects. With the exception of a few morphometric characteristics such as the bronchial wall thickness (WT), very little has been published concerning the effects of disease on the tree structure and geometrical features. In this study, a commercial software package was used to segment the airway tree of seven healthy and six moderately persistent asthmatic patients from high resolution computed tomography images. The process was assessed with regards to the treatment of the images of the asthmatic group. The in vivo results for the bronchial length, diameter, WT, branching, and rotation angles are reported and compared per generation for different lobes. Furthermore, some popular mathematical relationships between these morphometric characteristics were examined in order to verify their validity for both groups. Our results suggest that, even though some relationships agree very well with previously published data, the compartmentalization of airways into lobes and the presence of disease may significantly affect the tree geometry, while the tree structure and airway connectivity is only slightly affected by the disease. Anat Rec, 296:852–866, 2013. © 2013 Wiley Periodicals, Inc.     

Fluid dynamics modeling of particulate deposition in the lungs

Detailed knowledge of the transport of air and particles in the human lungs is needed for two reasons: the selection of the right dosage of aerosol drugs used in respiratory therapy and the analysis of the maximum allowable concentration for particulate in air. This work is the first step of a more complex study, purpose of which is to provide some predictive relationships in order to evaluate the depth reached by the particles in the lungs as a function of their size using numerical modeling. In this phase we validated our numerical method, comparing the obtained results with those found in the literature. The Computational Fluid Dynamics code FLUENT 6 with the Eulerian-Lagrangian approach was used to simulate particle trajectories. A model of double bifurcation,based on the morphometric studies by Weibel and Hammersley and Olson, was adopted in order to represent the whole central part of the respiratory system with the same geometry,appropriately scaled down. A method to create a realistic velocity profile at the inlet of the domain was developed, in order to obtain data about particle deposition also reliable about the first bifurcation, unlike previous works.     

How Effective Are Geometric Morphometric Techniques for Assessing Functional Shape Variation? An Example From the Great Ape Temporomandibular Joint

Functional shape analyses have long relied on the use of shape ratios to test biomechanical hypotheses. This method is powerful because of the ease with which results are interpreted, but these techniques fall short in quantifying complex morphologies that may not have a strong biomechanical foundation but may still be functionally informative. In contrast, geometric morphometric methods are continually being adopted for quantifying complex shapes, but they tend to prove inadequate in functional analyses because they have little foundation in an explicit biomechanical framework. The goal of this study was to evaluate the intersection of these two methods using the great ape temporomandibular joint as a case study. Three‐dimensional coordinates of glenoid fossa and mandibular condyle shape were collected using a Microscribe digitizer. Linear distances extracted from these landmarks were analyzed using a series of one‐way ANOVAs; further, the landmark configurations were analyzed using geometric morphometric techniques. Results suggest that the two methods are broadly similar, although the geometric morphometric data allow for the identification of shape differences among taxa that were not immediately apparent in the univariate analyses. Furthermore, this study suggests several new approaches for translating these shape data into a biomechanical context by adjusting the data using a biomechanically relevant variable. © 2013 Wiley Periodicals, Inc.