Four-dimensional Visualization Research Articles

Four‐Dimensional Visualization of Accessory Mitral Valve Tissue and Cleft Mitral Valve Movement

Mini‐AbstractA 26‐year‐old woman was referred to our department due to cardiac tumor. She was asymptomatic, and transthoracic echocardiography showed accessory mitral valve tissue (AMVT) associated with cleft mitral valve. There was no left ventricular outflow obstruction, but we could identify the three‐dimensional movement of AMVT and cleft mitral valve. Four‐dimensional transthoracic echocardiography enabled us to reveal the real time movement of these structures precisely. In particular, en face visualization of cleft mitral valve and accessory mitral valve cannot be obtained by two‐dimensional echocardiography.

4D Visualization of a Cathode Catalyst Layer in a Polymer Electrolyte Fuel Cell by 3D Laminography–XAFS

Four-dimensional visualization of Pt/C cathode catalyst layers in membrane electrode assemblies (MEAs) were successfully performed by a newly developed method, namely laminography–XAFS (X-ray absorption fine structure). The method not only enables imaging of the 3D distribution of Pt nanoparticle cathode catalysts, but also the chemical states of the Pt catalysts in fresh and degraded MEAs in a nondestructive manner.

A pilot study of four-dimensional visualization of mandibular and temporomandibular joint movement

Background: Mandibular movements are reliable indicators of mandibular system disease and changes in movements can be useful to estimate treatment effect. Detection of mandibular movement is important. Objectives: We evaluated four-dimensional (4D) visualization of mandibular and temporomandibular joint movement using 320-row computed tomography (CT). Methods: A stepwise mouth gag was placed between mandibular and maxillary incisors to control mouth opening (0.5-cm increments) in healthy volunteers and one temporomandibular disorder (TMD) patient. A 320-row CT Joint-Move and Shot sequence was used for scanning with an image taken after each increment. 4D reconstruction was used to establish volume data. Results: 4D visualization of joint and dentition in a rest state and in a state of mandibular movement from multiple angles and in different planes demonstrated differences between healthy subjects and the subject with TMD. The effective dose per scan was approximately 17% of the 16-slice spiral CT. Conclusion: 4D visualization of mandibular movement can be achieved through 320-row volume CT, which may provide a diagnosis of temporomandibular joint disorder and assessment of treatment effects. Keywords: Four-dimensional visualization, mandible, temporomandibular joint, 320 CT

Pseudohaptic interaction with knot diagrams

To make progress in understanding knot theory, we need to interact with the projected representations of mathematical knots, which are continuous in three dimensions (3-D) but significantly interrupted in the projective images. One way to achieve such a goal is to design an interactive system that allows us to sketch two-dimensional (2-D) knot diagrams by taking advantage of a collision-sensing controller and explore their underlying smooth structures through a continuous motion. Recent advances of interaction techniques have been made that allow progress in this direction. Pseudohaptics that simulate haptic effects using pure visual feedback can be used to develop such an interactive system. We outline one such pseudohaptic knot diagram interface. Our interface derives from the familiar pencil-and-paper process of drawing 2-D knot diagrams and provides haptic-like sensations to facilitate the creation and exploration of knot diagrams. A centerpiece of the interaction model simulates a physically reactive mouse cursor, which is exploited to resolve the apparent conflict between the continuous structure of the actual smooth knot and the visual discontinuities in the knot diagram representation. Another value in exploiting pseudohaptics is that an acceleration (or deceleration) of the mouse cursor (or surface locator) can be used to indicate the slope of the curve (or surface) of which the projective image is being explored. By exploiting these additional visual cues, we proceed to a full-featured extension to a pseudohaptic four-dimensional (4-D) visualization system that simulates the continuous navigation on 4-D objects and allows us to sense the bumps and holes in the fourth dimension. Preliminary tests of the software show that main features of the interface overcome some expected perceptual limitations in our interaction with 2-D knot diagrams of 3-D knots and 3-D projective images of 4-D mathematical objects.

New insight into the slope mass rating geomechanical classification through four-dimensional visualization

Slope Mass Rating (SMR) is a widely used rock mass classification intended to characterize and classify rocky slopes. It is based on basic Rock Mass Rating (RMRb), and is obtained by subtracting a factorial correction factor depending on the discontinuity and the slope face geometrical relationship (F1×F2×F3), and adding a correction factor depending on the excavation method (F4). Originally, SMR classification was established empirically from the study of twenty-eight slopes affected by different degrees of instability. As a consequence, an analysis of SMR classification seems to be necessary in order to better understand the performance of this rock mass classification. In this paper, a four-dimensional visual analysis of SMR geomechanical classification by means of the Worlds within Worlds methodology is performed in order to explore, analyze and visualize the relationship among the main controlling parameters of this geomechanical classification. The study reveals that several cases exist where the slope-discontinuity geometrical relationship scarcely affects slope stability, and as a consequence SMR can be computed by correcting basic RMR only with the F4 factor.

Four-dimensional visualization of single and multiple laser filaments using in-line holographic microscopy

It is shown, both through simulations and experiments, that the in-line holographic microscopy technique can be used to retrieve very small refractive-index perturbations caused during the filamentation of ultrashort laser pulses. This technique provides the possibility of having spatially and temporally (four dimensions) resolved measurements of refractive-index changes, down to 10${}^{\ensuremath{-}4}$, from objects with diameters as small as 10 \ensuremath{\mu}m. Moreover, we demonstrate the power of the technique in discriminating multiple filaments in a precise quantitative way.

Public Preferences on the Use of Visualization in the Public Involvement Process in Transportation Planning

This study examines public preferences on the use of visualization techniques to involve the public in transportation planning. Two projects were selected, and prototype two-dimensional, three-dimensional, and four-dimensional visualization models were developed. The models were presented at public meetings where stated preference surveys were conducted. The same models were also presented in a survey conducted via the Internet. A majority of both the 31 questionnaire respondents and the 136 Internet-based survey respondents ranked the two-dimensional, three-dimensional, and four-dimensional visualization techniques in increasing order of their abilities to convey the proposed project concepts. More than 71% of the respondents thought that transportation planning agencies should devote more time and budget to develop advanced visualization models to encourage public participation. In addition, more than 75% of the respondents indicated that they would be more willing to participate and encourage others to participate in the public involvement process if better visualization tools were used.

Four-dimensional visualization of thoracic blood flow by magnetic resonance imaging in a patient following correction of transposition of the great arteries (d-tga) and uncorrected aortic coarctation

Recent advances in flow-sensitive magnetic resonance imaging (MRI) and data analysis allow for comprehensive noninvasive three-dimensional (3D) visualization of complex blood flow. Electrocardiogram (ECG)-gated three-directional (3dir) flow measurements were employed to assess and visualize time-resolved 3D blood flow in the pulmonary arteries (PA) and thoracic aorta. We present findings in a juvenile patient with surgically corrected transposition of the great arteries (d-TGA) and aortic coarctation. For the first time, the complex flow patterns in the PA following d-TGA were visualized. Morphologically, a slight asymmetry of the PA was found, with considerable impact on vascular hemodynamics, resulting in diastolic retrograde flow in the larger vessel and diastolic filling of the smaller PA. Additionally, increased flow to the supraaortic vessels was found due to aortic coarctation.

Four-dimensional visualization with optical coherence tomography

Four-dimensional visualization with optical coherence tomography

Four-dimensional visualization of mandibular movement using an individual's head model reconstructed from cephalograms

We introduce a new four-dimensional (4D) visualizing system of stomatognathic function that combines an individual's 3D head model, reconstructed from cephalograms, and mandibular movement data recorded with a six degrees-of-freedom jaw movement analyzer. The individual's head model was constructed by transforming a standard head model according to the 3D coordinate values calculated from the individual's cephalograms. The accuracy of the 3D reconstructed head model was determined. The error averaged 1.02%, with a range of 0.39–1.58%, and the accuracy was sufficient for clinical use. This method performs dynamic and precise simulation of mandibular movement. We believe that our system will be useful for evaluating the functional background of patients with malocclusions and maxillofacial deformities.

Three- and four-dimensional visualization of human prenatal development using MR microscopy, ultrasonography and computer graphics

Three- and four-dimensional visualization of human prenatal development using MR microscopy, ultrasonography and computer graphics

The Embryonic Vertebrate Heart Tube Is a Dynamic Suction Pump

The embryonic vertebrate heart begins pumping blood long before the development of discernable chambers and valves. At these early stages, the heart tube has been described as a peristaltic pump. Recent advances in confocal laser scanning microscopy and four-dimensional visualization have warranted another look at early cardiac structure and function. We examined the movement of cells in the embryonic zebrafish heart tube and the flow of blood through the heart and obtained results that contradict peristalsis as a pumping mechanism in the embryonic heart. We propose a more likely explanation of early cardiac dynamics in which the pumping action results from suction due to elastic wave propagation in the heart tube.

Four-Dimensional Visualization of Construction Scheduling and Site Utilization

Four-dimensional ~4D! models link three-dimensional geometrical models with construction schedule data. The visual link between the schedule and construction site conditions is capable of facilitating decision making during both the planning and construction stages. The emphases of these 4D developments have often been placed at the level of construction components. Practical features assisting site management are at times lacking in the following areas: ~1! generation of site usage layouts; ~2! estimation of quantities of construction materials; and ~3! cost evaluation. In order to pinpoint these deficiencies, the objective of this work is to enable visual study of the effects of job progress on the logistics and resource schedules. This paper presents a 4D visualization model that is intended both to help construction managers plan day-to-day activities more efficiently in a broader and more practical site management context and to thereby add to our knowledge and understanding of the relevance of modern computer graphics to the responsibilities of the construction site manager. A brief site trial of the software is described at the conclusion of the paper.

Three- and four-dimensional visualization of magnetic resonance imaging data sets in pediatric cardiology.

The purpose of medical imaging technology in pediatric cardiology is to provide clear representations of the underlying anatomy and physiology of the cardiovascular system--representations that are easily understood and that facilitate clinical decision making. However, standard projective and tomographic imaging methods often yield results that are intelligible only to imaging specialists. Three- and four-dimensional reconstructions from projective and tomographic data sets are an alternative form of image display. Often, these reconstructions are more readily comprehensible as representations of the reality apparent in the operating room or the pathology laboratory than are the original data sets. Furthermore, viewing of these reconstructions is much more time efficient than viewing hundreds of separate tomographic images. Magnetic resonance imaging inherently provides three-, four-, and even higher dimensional data, and magnetic resonance data sets are commonly used to generate volumetric reconstructions. This review will focus on the practical application of magnetic resonance imaging to yield three- and four-dimensional reconstructions of pediatric cardiovascular disorders.