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Photorealistic virtual anatomy based on Chinese Visible Human data.

Virtual reality based learning of human anatomy is feasible when a database of 3D organ models is available for the learner to explore, visualize, and dissect in virtual space interactively. In this article, we present our latest work on photorealistic virtual anatomy applications based on the Chinese Visible Human (CVH) data. We have focused on the development of state-of-the-art virtual environments that feature interactive photo-realistic visualization and dissection of virtual anatomical models constructed from ultra-high resolution CVH datasets. We also outline our latest progress in applying these highly accurate virtual and functional organ models to generate realistic look and feel to advanced surgical simulators.

Adult↗

Physiological monitoring as an objective tool in virtual reality therapy.

The goals of this study were twofold: (1) to investigate nonphobics' and phobics' physiological response in virtual environments, and (2) to analyze the trend of phobics' physiology during virtual reality (VR) treatment. As a measure of physiology, heart rate, skin resistance, and skin temperature were acquired. The data for two groups of participants were analyzed: 22 nonphobic participants (mean = 32 +/- 9.4 years) and 36 subjects with fear of flying (mean = 40 +/- 12.1 years) who met the DSM-IV criteria for fear of flying. As a result, skin resistance showed significant differences between nonphobics and phobics, T(56) = 2.978 and p < 0.01, respectively. The physiological response of 33 phobic participants, who were able to fly without medicine after VR treatment, showed a gradual trend toward the nonphobics' physiological responses as therapy sessions progressed. In this study, physiological monitoring, in particular skin resistance, appeared to be useful both in understanding the physiological state of phobic individuals and in evaluating the results of treatment in VR psychotherapy.

Adult↗

Manual and virtual rotation of a three-dimensional object.

An orientation-matching task, based on a mental rotation paradigm, was used to investigate how participants manually rotated a Shepard-Metzler object in the real world and in an immersive virtual environment (VE). Participants performed manual rotation more quickly and efficiently than virtual rotation, but the general pattern of results was similar for both. The rate of rotation increased with the starting angle between the stimuli meaning that, in common with many motor tasks, an amplitude-based relationship such as P. M. Fitts' (1954) law is applicable. When rotation was inefficient (i.e., not by the shortest path), it was often because participants incorrectly perceived the orientation of one of the objects, and this happened more in the VE than in the real world. Thus, VEs allow objects to be manipulated naturally to a limited extent, indicating the need for timing-scale factors to be used for applications such as method-time-motion studies of manufacturing operations.

Adult↗

Development of an experimental paradigm in which to examine human learning using two computer-based formats.

Computer-based self-instructional programs are frequently promoted as means to augment or replace the traditional anatomy curricula taught in medical schools. These programs may range from static slide shows to fully immersive virtual environments. However, the impact of these learning technologies on knowledge acquisition, and their comparative cost/benefit to education remain unclear. As a consequence, we are embarking on a series of experiments to compare knowledge acquisition and the meaningful use of information among students who are learning anatomy using one of two different computer-based self-instructional formats. These studies will be based on a specially developed learning module on basic lung anatomy; they will utilize a variety of assessment tools to measure factual knowledge, conceptual understanding of spatial-anatomic relationships, and the ability to apply newly acquired knowledge of anatomy to clinical problem-solving scenarios. The primary object of this paper is to describe the design and development of the underlying test module and to outline the two computer-based formats that will be evaluated. The virtual reality (VR) environment, UCSD's Anatomic VisualizeR, provides dynamic access to 3-dimensional polygonal models of the lesson content and supports student-centered exploration and learning. The multimedia environment, Microsoft PowerPoint, provides a structured presentation of the lesson content and illustrates important anatomic structures through the use of 2-dimensional images derived by screen captures of models available in the VR learning module. This paper also provides an overview of the first experiment in the series, a pilot study using first-year medical students without previous participation in a medical school anatomy curriculum. For this study, students will be prospectively randomized into two groups, each group learning the lung anatomy lesson using one of the computer-based formats described. Immediate knowledge retention will be measured by asking students to complete the assessment instrument immediately after completing their learning module. The results of the pilot study will be used to refine and improve the design of the remainder of studies planned in this experimental series.

Anatomy↗

Virtual reality as an adjunctive pain control during burn wound care in adolescent patients.

For daily burn wound care procedures, opioid analgesics alone are often inadequate. Since most burn patients experience severe to excruciating pain during wound care, analgesics that can be used in addition to opioids are needed. This case report provides the first evidence that entering an immersive virtual environment can serve as a powerful adjunctive, nonpharmacologic analgesic. Two patients received virtual reality (VR) to distract them from high levels of pain during wound care. The first was a 16-year-old male with a deep flash burn on his right leg requiring surgery and staple placement. On two occasions, the patient spent some of his wound care in VR, and some playing a video game. On a 100 mm scale, he provided sensory and affective pain ratings, anxiety and subjective estimates of time spent thinking about his pain during the procedure. For the first session of wound care, these scores decreased 80 mm, 80 mm, 58 mm, and 93 mm, respectively, during VR treatment compared with the video game control condition. For the second session involving staple removal, scores also decreased. The second patient was a 17-year-old male with 33.5% total body surface area deep flash burns on his face, neck, back, arms, hands and legs. He had difficulty tolerating wound care pain with traditional opioids alone and showed dramatic drops in pain ratings during VR compared to the video game (e.g. a 47 mm drop in pain intensity during wound care). We contend that VR is a uniquely attention-capturing medium capable of maximizing the amount of attention drawn away from the 'real world', allowing patients to tolerate painful procedures. These preliminary results suggest that immersive VR merits more attention as a potentially viable form of treatment for acute pain.

Adolescent↗

Individual differences in spatial learning from computer-simulated environments.

A multivariate study examined relationships between the following factors: paper-and-pencil assessments of verbal and spatial ability, ability to form an accurate spatial representation of a large real-world environment, gender, computer attitudes and experience, proficiency with the navigational interface of a virtual environment (VE), and the ability to acquire and transfer spatial knowledge from a VE. Psychometrically assessed spatial ability and proficiency with the navigational interface were found to make substantial contributions to individual differences in the ability to acquire spatial information from a VE. Gender influenced many VE-related tasks, primarily through its relationship with interface proficiency and spatial ability. Measures of spatial knowledge of a VE maze were highly predictive of subsequent performance in a similar real-world maze, suggesting that VEs can be useful for training people about real-world spaces.

Adult↗

Distance underestimation in virtual space is sensitive to gender but not activity-passivity or mode of interaction.

Four groups of undergraduates (half of each gender) experienced a movement along a corridor containing three distinctive objects, in a virtual environment (VE) with wide-screen projection. One group simulated walking along the virtual corridor using a proprietary step-exercise device. A second group moved along the corridor in conventional flying mode, depressing a keyboard key to initiate continuous forward motion. Two further groups observed the walking and flying participants, by viewing their progress on the screen. Participants then had to walk along a real equivalent but empty corridor, and indicate the positions of the three objects. All groups underestimated distances in the real corridor, the greatest underestimates occurring for the middle distance object. Males' underestimations were significantly lower than females' at all distances. However, there was no difference between the active participants and passive observers, nor between walking and flying conditions.

Adolescent↗

Virtual reality: past, present and future.

This report provides a short survey of the field of virtual reality, highlighting application domains, technological requirements, and currently available solutions. The report is organized as follows: section 1 presents the background and motivation of virtual environment research and identifies typical application domain, section 2 discusses the characteristics a virtual reality system must have in order to exploit the perceptual and spatial skills of users, section 3 surveys current input/output devices for virtual reality, section 4 surveys current software approaches to support the creation of virtual reality systems, and section 5 summarizes the report.

Computer Simulation↗

Distinct neural substrates for the perception of real and virtual visual worlds.

Virtual environments have been frequently used for training and skill improvement. However, do real and virtual worlds engage the same brain states in human perceivers? We measured brain activity using functional magnetic resonance imaging (fMRI) while adults watched movie and cartoon clips, simulating real and virtual visual worlds, respectively. Relative to baselines using random static images, the medial prefrontal cortex (MPFC) and the cerebellum were activated only by movie clips of other humans. In contrast, cartoon clips of human and non-human agents activated the superior parietal lobes, while movie clips of animals also activated the superior parietal lobes. Our fMRI findings suggest that the perception of real-world humans is characterised by the involvement of MPFC and the cerebellum, most likely for on-line representation of the mental states of others, whereas the perception of virtual-world agents engages the parietal cortex in attention to actions.

Adult↗

GeRTiSS: Generic Real Time Surgery Simulation.

Minimally invasive surgery is a technique that permits interventions through very small incisions. This minimises the patients' trauma and permits a faster recovery in comparison with classical surgery. The disadvantage of this surgery technique, though, is its complexity, requiring a high training effort of the surgeon. In this paper, we present a general surgery simulator for training surgeons in minimally invasive surgery. The application allows to create environments and interaction modes very similar to those encountered in real surgical interventions. The virtual environments are optionally composed of an actual patient's organs the intervention on which one desires to practice in a beforehand manner, or of synthetically generated organs with arbitrary pathologies. The intervention is carried out by means of haptic interfaces with force feedback, providing the surgeon with a sense of touch, a fundamental element of all types of surgery.

Computer Simulation↗

New trends in the virtualization of hospitals--tools for global e-Health.

The development of virtual hospitals and digital medicine helps to bridge the digital divide between different regions of the world and enables equal access to high-level medical care. Pre-operative planning, intra-operative navigation and minimally-invasive surgery require a digital and virtual environment supporting the perception of the physician. As data and computing resources in a virtual hospital are distributed over many sites the concept of the Grid should be integrated with other communication networks and platforms. A promising approach is the implementation of service-oriented architectures for an invisible grid, hiding complexity for both application developers and end-users. Examples of promising medical applications of Grid technology are the real-time 3D-visualization and manipulation of patient data for individualized treatment planning and the creation of distributed intelligent databases of medical images.

Artificial Intelligence↗

Distance estimation in a dynamic simulated environment: a visual field dependence problem?

Egocentric distance estimation implies that the subject perceives his own location in the environment. In a simulated environment, subjects have to transpose perceptively their own observation point in order to assume their virtual body position. As only visual information specifies this position, their ability to perceive the camera viewpoint should be linked to the field dependence independence factor (FDI). Field-independent subjects underestimated the mid-distance between their own virtual body position and a far-located target; their bisection was located between the projective (2-D) and the simulated (3-D) mid-distance which indicates their difficulty in considering the in-depth simulated spatial references. High correlations between the vertical estimation in the rod-and-frame test and the egocentric-distance-estimation task (with shifted camera) suggest a similar perceptive process in both tasks. This result is confirmed by the better performances of the field-dependent subjects in this condition. In conclusion, we discuss the relationship between FDI and the sense of presence in virtual environments.

Adult↗

Effects of characteristics of image quality in an immersive environment.

Image quality issues such as field of view (FOV) and resolution are important for evaluating "presence" and simulator sickness (SS) in virtual environments (VEs). This research examined effects on postural stability of varying FOV, image resolution, and scene content in an immersive visual display. Two different scenes (a photograph of a fountain and a simple radial pattern) at two different resolutions were tested using six FOVs (30, 60, 90, 120, 150, and 180 deg.). Both postural stability, recorded by force plates, and subjective difficulty ratings varied as a function of FOV, scene content, and image resolution. Subjects exhibited more balance disturbance and reported more difficulty in maintaining posture in the wide-FOV, high-resolution, and natural scene conditions.

Adult↗

The Informatics Collaboratory: building an online community to support health care informatics students.

For the past decade, the School of Nursing has examined the role of computer mediated communication and virtual environments in both health care and educational systems. This recent project, the I-Collaboratory, draws upon previous work and builds on recent studies examining the role of social presence in learning communities. The I-Collaboratory creates a virtual infrastructure to support a collaborative learning environment for Master level students in a web-based health care informatics program. This innovative and supportive environment allows students to learn through collaborative inter-actions and have access to a cadre of professionals associated with nursing, informatics and health care. This paper provides an introduction to the concept of a collaboratory and describes the set of principles derived from the literature that serve as a foundation. The process of selecting a web-based platform and the development of the online community based on the results of a need assessment is also detailed. The paper concludes with an outline of the online community components and the plans for evaluation.

Cooperative Behavior↗

Distances appear different on hills.

When walking effort is increased due to manipulations such as wearing heavy backpacks, people perceive hills to be steeper and distances to be farther (Bhalla & Proffitt, 1999; Proffitt, Stefanucci, Banton, & Epstein, 2003). On the basis of these findings, we expected people to overestimate distances on steep hills relative to the same distances on flat ground, because of the increased effort required to ascend or descend them. This hypothesis is in contrast to the belief that distances are specified solely by optical and oculomotor information related to the geometry of the environment. To test the hypothesis, we investigated distance estimation on hills and flat terrains in natural and virtual environments. We found that participants judged steep uphill and downhill distances to be farther than the same distances on flat terrain. These results are inconsistent with the idea that spatial layout is perceived solely in terms of geometry, lending partial support to an effort hypothesis.

Adult↗

The virtual aneurysm. Virtual reality in endovascular therapy.

Image guided therapies, such as new endovascular procedures for treating brain aneurysms are now in clinical use. To plan these procedures, physicians currently use angiography to view projectional images of anatomy and blood flow. There are currently no available tools for visualizing the details of complex blood flow or predicting the effects of specific treatments. To address this problem, we have created a virtual environment for the visualization of blood flow and the simulated effects of therapy in brain aneurysms. The "Virtual Aneurysm" is composed using a combination of image processing, flow simulation, scientific visualization, and virtual reality techniques.

Angiography, Digital Subtraction↗

The development of virtual reality therapy (VRT) system for the treatment of acrophobia and therapeutic case.

Virtual reality therapy (VRT), based on this sophisticated technology, has been recently used in the treatment of subjects diagnosed with acrophobia, a disorder that is characterized by marked anxiety upon exposure to heights and avoidance of heights. Conventional VR systems for the treatment of acrophobia have limitations, over-costly devices or somewhat unrealistic graphic scenes. The goal of this study was to develop an inexpensive and more realistic virtual environment (VE) in which to perform exposure therapy for acrophobia. It is based on a personal computer, and a virtual scene of a bunge-jump tower in the middle of a large city. The virtual scenario includes an open lift surrounded by props beside a tower, which allows the patient to feel a sense of heights. The effectiveness of the VE was evaluated through the clinical treatment of a subject who was suffering from the fear of heights. As a result, it was proved that this VR environment was effective and realistic at overcoming acrophobia according not only to the comparison results of a variety of questionnaires before and after treatment but also to the subject's comments that the VE seemed to evoke more fearful feelings than the real situation.

Chronic Disease↗

Ventriloquism aftereffects occur in the rear hemisphere.

After exposure to a consistent spatial disparity of auditory and visual stimuli, subjective localization of sound sources is usually shifted in the direction of the visual stimuli. This study investigates whether such aftereffects can be observed in humans after exposure to a conflicting bimodal stimulation in virtual reality and whether these aftereffects are confined to the trained locations. Fourteen subjects participated in an adaptation experiment, in which auditory stimuli were convolved with non-individual head-related transfer functions, delivered via headphones. First, we assessed the auditory localization of subjects in darkness. They indicated the perceived direction of a sound using an angular pointer. We then immersed the subjects in a virtual environment by means of a head-mounted display. They were asked to reproduce sequences of movements of virtual objects with a mouse click on the objects. However, we introduced a spatial disparity of 15 degrees between the visual event and the concurrent auditory stimulation. After 20 min of exposure, we tested the subjects again in total darkness to determine whether their auditory localization system had been modified by the conflicting visual signals. We observed a shift of subjective localization towards the left in both dorsal and frontal hemifields of the subject, mainly for auditory stimuli located in the right hemispace. This result suggests that interaural difference cues and monaural spectral cues were not equally adapted, and that visual stimuli mainly influence the processing of binaural directional cues of sound localization.

Acoustic Stimulation↗