Virtual Anatomical and Endoscopic Exploration Method of Internal Human Body for Training Simulator.

BACKGROUND: Virtual environments have brought the use of realistic training closer to many different fields of education. In medical education, several visualization methods for studying inside the human body have been introduced as a way to verify the structure of internal organs. However, these methods are insufficient for realistic training simulators because they do not provide photorealistic scenes or offer an intuitive perception to the user. In addition, they are used in limited environments within a classroom setting. METHODS: We have developed a virtual dissection exploration system that provides realistic three-dimensional images and a virtual endoscopic experience. This system enables the user to manipulate a virtual camera through a human organ, using gesture-sensing technology. We can make a virtual dissection image of the human body using a virtual dissection simulator and then navigate inside an organ using a virtual endoscope. To improve the navigation performance during virtual endoscopy, our system warns the user about any potential collisions that may occur against the organ's wall by taking the virtual control sphere at the virtual camera position into consideration. RESULTS: Experimental results show that our system efficiently provides high-quality anatomical visualization. We can simulate anatomic training using virtual dissection and endoscopic images. CONCLUSION: Our training simulator would be helpful in training medical students because it provides an immersive environment.

Reliable subsurface scattering for volume rendering in three-dimensional ultrasound imaging.

Light effects have been frequently used in volume rendering because they can depict the shapes of objects more realistically. Global illumination reflects light intensity values at relevant pixel positions of reconstructed images based on the considerations of scattering and extinction phenomena. However, in the cases of ultrasound volumes that do not use Cartesian coordinates, internal lighting operations generate errors owing to the distorted direction of light propagation, and thus increase the amount of light and its effects according to the position of the volume inside. In this study, we present a novel global illumination method with calibrated light along the progression direction in accordance with volume ray casting in non-Cartesian coordinates. In addition, we reduce the consumption of lighting operation in these lighting processes using a light-distribution template. Experimental results show the volume rendering outcomes in non-Cartesian coordinates that realistically visualize the global illumination effect. The light scattering effect is expressed uniformly in the top and bottom areas where many distortions are generated in the ultrasound coordinates by using the light template kernels adaptively. Our method can effectively identify dark areas that are invisible owing to differences in brightness at the upper and lower regions of the ultrasound coordinates. Our method can be used to realistically show the shapes of the fetus during relevant examinations with ultrasonography.

True-color face peeled images with botulinum toxin injection sites and anatomic landmarks / Imágenes de color verdadero de rostros sin piel con puntos de inyección de toxina botulínica y puntos de referencia anatómicos

To allow students and surgeons to learn the sites for botulinum toxin injection, new types of educational images are needed because MRI, CT, and sectioned images are inadequate. This article describes browsing software that displays face peeled images that allow layers along the curved surface of the face to be peeled gradually in even depths across the surface. Two volume models of the head were reconstructed from sectioned images and segmented images of Visible Korean, respectively. These volume models were peeled serially at a thickness of 0.2 mm along the curved surface of the facial skin to construct the peeled images and peeled segmented images. All of the peeled images were marked with botulinum toxin injection sites, facial creases and wrinkles, and fat compartments. All peeled images and the text information were entered into browsing software. The browsing software shows 12 botulinum toxin injection sites on all peeled images of the anterior and lateral views. Further, the software shows 23 anatomic landmarks, 13 facial creases and wrinkles, and 7 face fat compartments. When a user points at any structure on the peeled images, the name of the structure appears. Our software featuring the peeled images will be particularly effective for helping medical students to quickly and easily learn the accurate facial anatomy for botulinum toxin injection sites. It will also be useful for explaining plastic surgery procedures to patients and studying the anatomic structure of the human face.

Para permitir que los estudiantes y cirujanos aprendan los sitios para la inyección de toxina botulínica, se necesitan nuevos tipos de imágenes educativas ya que las imágenes de MRI, CT e imágenes seccionadas son inadecuadas. Este artículo describe el software de navegación que muestra imágenes de cara sin piel que permiten que las capas a lo largo de la superficie curva de la cara se despeguen gradualmente en profundidades uniformes a lo largo de la superficie. Se reconstruyeron dos modelos de volumen de la cabeza a partir de imágenes seccionadas e imágenes segmentadas visibles, respectivamente. En estos modelos de volumen se retiró la piel en serie con un grosor de 0,2 mm a lo largo de la superficie curva de la cara para construir las imágenes sin piel y las imágenes segmentadas sin piel. Todas las imágenes sin piel se marcaron con puntos de inyección de toxina botulínica, arrugas y arrugas faciales y compartimientos de grasa. Todas las imágenes despegadas y la información de texto se ingresaron en el software de navegación. El software de navegación muestra 12 sitios de inyección de toxina botulínica en todas las imágenes de las vistas anterior y lateral. Además, el software muestra 23 puntos de referencia anatómicos, 13 pliegues y arrugas faciales y 7 compartimentos de grasa facial. Cuando un usuario selecciona cualquier estructura en las imágenes sin piel, aparece el nombre de la estructura. Nuestro software con las imágenes sin piel será particularmente efectivo para ayudar a los estudiantes de medicina a aprender rápida y fácilmente la anatomía facial precisa para los sitios de inyección de toxina botulínica. También será útil para explicar los procedimientos de cirugía plástica a pacientes y estudiar la estructura anatómica del rostro humano.

New Viewpoint of Surface Anatomy Using the Curved Sectional Planes of a Male Cadaver.

BACKGROUND: The curved sectional planes of the human body can provide a new approach of surface anatomy that the classical horizontal, coronal, and sagittal planes cannot do. The purpose of this study was to verify whether the curved sectional planes contribute to the morphological comprehension of anatomical structures. METHODS: By stacking the sectioned images of a male cadaver, a volume model of the right half body was produced (voxel size 1 mm). The sectioned images with the segmentation data were also used to build another volume model. The volume models were peeled and rotated to be screen captured. The captured images were loaded on user-friendly browsing software that had been made in the laboratory. RESULTS: The browsing software was downloadable from the authors' homepage (anatomy.co.kr). On the software, the volume model was peeled at 1 mm thicknesses and rotated at 30 degrees. Since the volume models were made from the cadaveric images, actual colors of the structures were displayed in high resolution. Thanks to the segmentation data, the structures on the volume model could be automatically annotated. Using the software, the sternocleidomastoid muscle and the internal jugular vein in the neck region, the cubital fossa in the upper limb region, and the femoral triangle in the lower limb region were observed to be described. CONCLUSION: For the students learning various medical procedures, the software presents the needed graphic information of the human body. The curved sectional planes are expected to be a tool for disciplinary convergence of the sectional anatomy and surface anatomy.

Three Software Tools for Viewing Sectional Planes, Volume Models, and Surface Models of a Cadaver Hand.

BACKGROUND: The hand anatomy, including the complicated hand muscles, can be grasped by using computer-assisted learning tools with high quality two-dimensional images and three-dimensional models. The purpose of this study was to present up-to-date software tools that promote learning of stereoscopic morphology of the hand. METHODS: On the basis of horizontal sectioned images and outlined images of a male cadaver, vertical planes, volume models, and surface models were elaborated. Software to browse pairs of the sectioned and outlined images in orthogonal planes and software to peel and rotate the volume models, as well as a portable document format (PDF) file to select and rotate the surface models, were produced. RESULTS: All of the software tools were downloadable free of charge and usable off-line. The three types of tools for viewing multiple aspects of the hand could be adequately employed according to individual needs. CONCLUSION: These new tools involving the realistic images of a cadaver and the diverse functions are expected to improve comprehensive knowledge of the hand shape.

Improved Software to Browse the Serial Medical Images for Learning.

The thousands of serial images used for medical pedagogy cannot be included in a printed book; they also cannot be efficiently handled by ordinary image viewer software. The purpose of this study was to provide browsing software to grasp serial medical images efficiently. The primary function of the newly programmed software was to select images using 3 types of interfaces: buttons or a horizontal scroll bar, a vertical scroll bar, and a checkbox. The secondary function was to show the names of the structures that had been outlined on the images. To confirm the functions of the software, 3 different types of image data of cadavers (sectioned and outlined images, volume models of the stomach, and photos of the dissected knees) were inputted. The browsing software was downloadable for free from the homepage (anatomy.co.kr) and available off-line. The data sets provided could be replaced by any developers for their educational achievements. We anticipate that the software will contribute to medical education by allowing users to browse a variety of images.

Surface models and gradually peeled volume model to explore hand structures.

This study was intended to confirm whether simultaneous examination of surface and volume models contributes to learning of hand structures. Outlines of the skin, muscles, and bones of the right hand were traced in sectioned images of a male cadaver to create surface models of the structures. After the outlines were filled with selected colors, the color-filled sectioned images were stacked to produce a volume model of the hand, from which the skin was gradually peeled. The surface models provided locational orientation of the hand structures such as extrinsic and intrinsic hand muscles, while the peeled volume model revealed the depth of the individual hand structures. In addition, the characteristic appearances of the radial artery and the wrist joint were confirmed. The exploration of the volume model accompanied by equivalent surface models is synergistically helpful for understanding the morphological properties of hand structures.

Making dentition model from negative dental impression in implant treatment / Fabricación de un modelo de dentición a partir de una impresión dental negativa para el tratamiento con implantes

In dental implant treatment or corrective surgery, a dental plaster model is produced to recognize the shape of the teeth. Understanding this dentition model is an important issue in prosthetic dentistry and craniomaxillofacial surgery. However, dental models are time consuming and costly to produce via traditional casting methods. We provide a method which makes dentition model from both a positive and a negative dental impression. Also we produce a system for making a digital dentition model using computed tomography (CT) data during the impression process. Additionally, the system allows the digital dentition model to be realized via a three-dimensional printer. The result simplifies production of the dentition model, since a physical model can be produced directly from an impression of the patient. Our system can simplify the dentition process and treatment intervention involved in making a dentition model. The digital model enables clinicians to manage the patient's cumulative data and to predict changes during the course of treatment.

En el tratamiento de implantes dentales, o cirugía correctiva, se produce un modelo de yeso dental para reconocer la forma de los dientes. La comprensión de este modelo de dentición es un tema importante en la odontología protésica y la cirugía craniomaxilofacial. Sin embargo, los modelos dentales con sumen tiempo y son costosos de producir a través de los métodos tradicionales de fundición. Proporcionamos un método que hace que el modelo de dentición sea tanto positivo como negativo. También proponemos un sistema para hacer un modelo de dentición digital utilizando datos de tomografía computarizada (TC) durante el proceso de impresión. Además, el sistema permite que el modelo de dentición digital se imprima a través de una impresora tridimensional. El resultado simplifica la producción del modelo de dentición, ya que un modelo físico puede ser producido directamente a partir de una impresión del paciente. Nuestro sistema puede simplificar el proceso de dentición y la intervención de tratamiento involucrados en la elaboración de un modelo de dentición. El modelo digital permite a los médicos manejar los datos acumulados del paciente y predecir los cambios durante el curso del tratamiento.

Peeled and piled volume models of the stomach made from a cadaver's sectioned images / Modelos de volumen descortezados y apilados del estómago producidos a partir de imágenes seccionales de un cadáver

Diagnosing and treating stomach diseases requires as many of the related anatomy details as possible. The objective of this study based on the sectioned images of cadaver was to offer interested clinicians anatomical knowledge about the stomach and its neighbors from the new viewpoint. For the raw data, sectioned images of a male cadaver without stomach pathology were used. By manual segmentation and automatic interpolation, a high-quality volume model of the stomach was reconstructed. The model was continuously peeled and piled to synthetically reveal the inside and outside of the stomach. The anterior, posterior, right, and left views of the models were compared with a chosen sectioned image. The numerous stomach images were then put into user-friendly browsing software. Some advantages of this study are that the sectioned images reveal real stomach color with high resolution; the peeled and piled volume models result in new features of the stomach and surroundings; and the processed models can be conveniently browsed in the presented software. These image data and tutorial software are expected to be helpful in acquiring supplementary morphologic information on the stomach and related structures.

El diagnóstico y el tratamiento de enfermedades del estómago requieren del conocimiento del mayor número de detalles posible sobre su anatomía. El objetivo de este estudio, basado en secciones de imágenes de cadáver, es ofrecer a los médicos la anatomía del estómago y sus estructuras vecinas desde un nuevo punto de vista. Se utilizaron imágenes de secciones de un cadáver, de sexo masculino, sin patología del estómago. Por segmentación manual y automática de interpolación, se reconstruyó un modelo de volumen de alta calidad del estómago. El modelo fue descortezado y apilado para revelar sintéticamente el interior y exterior del estómago. Se compararon los puntos de vista anterior, posterior, derecho e izquierdo de los modelos en una sección elegida. Las numerosas imágenes del estómago luego fueron puestas en el software de navegación de fácil uso para el profesional. Algunas de las ventajas de este estudio son que las imágenes seccionadas revelan el color real del estómago con alta resolución; los modelos de volumen descortezados y apilados dan lugar a nuevas funciones del estómago y sus estructuras circundantes; y los modelos procesados pueden ser convenientemente navegados en el software presentado. Se espera que estos datos de imagen y el tutorial del programa sean de utilidad para la adquisición de información morfológica complementaria sobre el estómago y las estructuras relacionadas.

Colonoscopy tutorial software made with a cadaver's sectioned images.

Novice doctors may watch tutorial videos in training for actual or computed tomographic (CT) colonoscopy. The conventional learning videos can be complemented by virtual colonoscopy software made with a cadaver's sectioned images (SIs). The objective of this study was to assist colonoscopy trainees with the new interactive software. Submucosal segmentation on the SIs was carried out through the whole length of the large intestine. With the SIs and segmented images, a three dimensional model was reconstructed. Six-hundred seventy-one proximal colonoscopic views (conventional views) and corresponding distal colonoscopic views (simulating the retroflexion of a colonoscope) were produced. Not only navigation views showing the current location of the colonoscope tip and its course, but also, supplementary description views were elaborated. The four corresponding views were put into convenient browsing software to be downloaded free from the homepage (anatomy.co.kr). The SI colonoscopy software with the realistic images and supportive tools was available to anybody. Users could readily notice the position and direction of the virtual colonoscope tip and recognize meaningful structures in colonoscopic views. The software is expected to be an auxiliary learning tool to improve technique and related knowledge in actual and CT colonoscopies. Hopefully, the software will be updated using raw images from the Visible Korean project.

A fast 3D adaptive bilateral filter for ultrasound volume visualization.

BACKGROUND AND OBJECTIVE: This paper introduces an effective noise removal method for medical ultrasound volume data. Ultrasound data usually need to be filtered because they contain significant noise. Conventional two-dimensional (2D) filtering methods cannot use the implicit information between adjacent layers, and existing 3D filtering methods are slow because of complicated filter kernels. Even though one filter method utilizes simple filters for speed, it is inefficient at removing noise and does not take into account the characteristics of ultrasound sampling. To solve this problem, we introduce a fast filtering method using parallel bilateral filtering and adjust the filter window size proportionally according to its position. METHODS: We devised a parallel bilateral filtering by obtaining a 3D summed area table of a quantized spatial filter. The filtering method is made adaptive by changing the kernel window size according to the distance from the ultrasound signal transmission point. RESULTS: Experiments were performed to compare the noise removal and loss of original data of the anisotropic diffusion filtering, bilateral filtering, and adaptive bilateral filtering of ultrasound volume-rendered images. The results show that the adaptive filter correctly takes into account the sampling characteristics of the ultrasound volumes. CONCLUSIONS: The proposed method can more efficiently remove noise and minimize distortion from ultrasound data than existing simple or non-adaptive filtering methods.

Interactive high-quality visualization of color volume datasets using GPU-based refinements of segmentation data.

Data sets containing colored anatomical images of the human body, such as Visible Human or Visible Korean, show realistic internal organ structures. However, imperfect segmentations of these color images, which are typically generated manually or semi-automatically, produces poor-quality rendering results. We propose an interactive high-quality visualization method using GPU-based refinements to aid in the study of anatomical structures. In order to represent the boundaries of a region-of-interest (ROI) smoothly, we apply Gaussian filtering to the opacity values of the color volume. Morphological grayscale erosion operations are performed to reduce the region size, which is expanded by Gaussian filtering. Pseudo-coloring and color blending are also applied to the color volume in order to give more informative rendering results. We implement these operations on GPUs to speed up the refinements. As a result, our method delivered high-quality result images with smooth boundaries and provided considerably faster refinements. The speed of these refinements is sufficient to be used with interactive renderings as the ROI changes, especially compared to CPU-based methods. Moreover, the pseudo-coloring methods used presented anatomical structures clearly.

Virtual Endoscopic and Laparoscopic Exploration of Stomach Wall Based on a Cadaver's Sectioned Images.

We intended to determine that virtual endoscopy and laparoscopy of the stomach based on serially sectioned cadaver images is beneficial. Therefore, the outlines between the gastric wall and lumen were traced using the new female data of the Visible Korean to build a volume model. While the outlines were expanded at appropriate thicknesses, the stomach was observed endoscopically and laparoscopically in comparison with a chosen sectioned image. Four layers (mucosa, submucosa, muscular layer, and serosa) of the stomach were discernible by their proper colors in the sectioned images. All layers except the submucosa were identified in the endoscopic and laparoscopic views by using consistent colors. The stepwise expansion of the outlines revealed thickness of each layer as well as whether the thickness was uniform. Our ideas and the Visible Korean images could be a robust resource of virtual reality learning for medical students and clinicians.

Multiple texture mapping of alveolar bone area for implant treatment in prosthetic dentistry.

Treatment using implants is frequently employed in prosthetic dentistry. In this method, determining the bone density of the upper and lower jaws is important. Generally, a dentist can recognize the condition of the alveolar bone to be manipulated using a cone-beam computed tomography (CBCT) image. However, communicating the data to the patient is a challenge because it is difficult for the nonprofessional person to interpret the image, which contains a distribution of pixels with similar density. We present an intuitive texture mapping method of the alveolar bone area for application in implant treatment. Our method aims to help patients better understand the treatment process by using a textured image that includes several different texture patterns that reflect the density of the alveolar bone area. We segment the area in accordance with the density of corresponding parts in the alveolar bone and the gingiva. By simplifying the boundary of each segmented region, the distribution of pixels with similar density on the alveolar bone area can be easily recognized. Next, the texture patterns for several segmented regions are mapped onto the alveolar bone area using the graph-cut algorithm, which is used for smooth texture mapping at the boundary of the segmented region. The result is an applied texture on the alveolar bone area that corresponds to the bone structure. Our method is helpful for facilitating communication and understanding of treatment using dental implants.

Laparoscopic and endoscopic exploration of the ascending colon wall based on a cadaver sectioned images.

For realistic virtual dissection, the sectioned images of a cadaver are a desirable material because of their high resolution and real body color. After a volume model is made of the sectioned images, it can be piled or peeled at the intended thickness as if a structure's surface is expanded and shrunken. The purpose of our study was to confirm whether laparoscopic and endoscopic exploration of the processed volume model plays a part in anatomy investigation. The ascending colon was outlined in serially sectioned images and accumulated to build a volume model. While the volume model was being piled or peeled, the ascending colon was observed laparoscopically and endoscopically in comparison with the original sectioned image. The trial efficiently demonstrated layers of the colon wall and surrounding tissues which could not be visualized by conventional macroscopic or microscopic techniques. The availability and contribution of this new method will be confirmed by application to other various organs.

GPU-accelerated 3D mipmap for real-time visualization of ultrasound volume data.

Ultrasound volume rendering is an efficient method for visualizing the shape of fetuses in obstetrics and gynecology. However, in order to obtain high-quality ultrasound volume rendering, noise removal and coordinates conversion are essential prerequisites. Ultrasound data needs to undergo a noise filtering process; otherwise, artifacts and speckle noise cause quality degradation in the final images. Several two-dimensional (2D) noise filtering methods have been used to reduce this noise. However, these 2D filtering methods ignore relevant information in-between adjacent 2D-scanned images. Although three-dimensional (3D) noise filtering methods are used, they require more processing time than 2D-based methods. In addition, the sampling position in the ultrasonic volume rendering process has to be transformed between conical ultrasound coordinates and Cartesian coordinates. We propose a 3D-mipmap-based noise reduction method that uses graphics hardware, as a typical 3D mipmap requires less time to be generated and less storage capacity. In our method, we compare the density values of the corresponding points on consecutive mipmap levels and find the noise area using the difference in the density values. We also provide a noise detector for adaptively selecting the mipmap level using the difference of two mipmap levels. Our method can visualize 3D ultrasound data in real time with 3D noise filtering.