An autostereoscopic 3D display can improve visualization of 3D models from intracranial MR angiography
An autostereoscopic display with image quality comparable to ordinary 2D displays has recently been developed. The purpose of our study was to evaluate whether the visualization of static 3D models from intracranial time-of-flight (TOF) MR angiography (MRA) was improved by this display.
Maximum Intensity Projection (MIP) and Volume Rendering (VR) 3D models of intracranial arteries were created from ten TOF MRA datasets. Thirty-one clinically relevant intracranial arterial segments were marked in the TOF source images. A total of 217 markings were used. The markings were displayed in the 3D models as overlying red dots. Three neuroradiologists viewed the static 3D models on the autostereoscopic display, with the display operating either in autostereoscopic mode or in 2D mode. The task of the neuroradiologists was to correctly identify the marked artery. A paired comparison was made between arterial identification in autostereoscopic and 2D display mode.
In 314 MIP 3D models, 233 arterial markings (74%) were correctly identified with the display operating in autostereoscopic mode versus 179 (57%) in 2D mode. Odds ratio for correct identification with autostereoscopic mode versus 2D mode was 2.17 (95% confidence interval 1.55-3.04, P < 0.001). In 337 VR 3D models, 256 markings (76%) were correctly identified using autostereoscopic mode and 229 (68%) using 2D mode (odds ratio 1.49, 95% confidence interval 1.06-2.09, P = 0.021).
The visualization of intracranial arteries in static 3D models from TOF MRA can be improved by the use of an autostereoscopic display.
Available from: Tim Killeen
- "The cost of stereoscopic projectors and polarising glasses have dropped significantly in recent years and the main cost of acquiring and using such systems now arises from the proprietary software and expertise necessary to construct the models. The DextroBeam system is only a step in the rapid evolution of VR teaching platforms, with novel systems enabling the display of stereoscopic models without the need for special glasses in development (Abildgaard et al., 2010). We are currently developing a further teaching intervention with an upgraded Dextrobeam setup and publication of this data will hopefully include accompanying videos. "
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ABSTRACT: Introduction: Three-dimensional (3D) computer graphics are increasingly used to supplement the teaching of anatomy. While most systems consist of a program which produces 3D renderings on a workstation with a standard screen, the Dextrobeam virtual reality VR environment allows the presentation of spatial neuroanatomical models to larger groups of students through a stereoscopic projection system.
Materials and Methods: Second-year medical students (n=169) were randomly allocated to receive a standardised pre-recorded audio lecture detailing the anatomy of the third ventricle accompanied by either a two-dimensional (2D) PowerPoint presentation (n=80) or a 3D animated tour of the third ventricle with the DextroBeam. Students completed a 10-question multiple-choice exam based on the content learned and a subjective evaluation of the teaching method immediately after the lecture.
Results: Students in the 2D group achieved a mean score of 5.19 (±2.12) compared to 5.45 (±2.16) in the 3D group, with the results in the 3D group statistically non-inferior to those of the 2D group (p<0.0001). The students rated the 3D method superior to 2D teaching in four domains (spatial understanding, application in future anatomy classes, effectiveness, enjoyableness) (p<0.01).
Conclusion: Stereoscopically-enhanced 3D lectures are valid methods of imparting neuroanatomical knowledge and are well received by students. More research is required to define and develop the role of large-group VR systems in modern neuroanatomy curricula.
Available from: Wijnand A Ijsselsteijn
- "This mode of representing blood vessels enhances the relative depth perception for the angiographic images (Wentz et al. 1991). Abildgaard et al. (2010) performed a study using clinical data, in which three neuroradiologists identified marked arteries in a series of images presented in 2D and 3D. Results showed that when presenting the images in 3D the identification of individual intracranial arterial segments improved compared to the 2D condition. "
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ABSTRACT: In this paper we review empirical studies concerning the effectiveness of stereoscopic displays in medicine. The domains covered in this review are: diagnosis, pre-operative planning, minimally invasive surgery (MIS) and training/teaching. For diagnosis, stereoscopic viewing of medical data has been shown to improve the sensitivity of tumor detection in breast imaging, and to improve the visualization of internal structures in 3D ultrasound. For MRI and CT data, where images are frequently rendered in 3D perspective, the added value of binocular depth has not yet been convincingly demonstrated. For MIS, stereoscopic displays decrease surgery time and increase accuracy of surgical procedures when the resolution of the stereoscopic displays is comparable to that of 2D displays. Training and surgical planning already use computer simulations; more research however is needed to assess the potential benefits of stereoscopic displays in those applications. Overall, there is a clear need for more empirical evidence that quantifies the added value of stereoscopic displays in medical domains.
Available from: Daniel Ruijters
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ABSTRACT: We present an approach for efficient rendering and transmitting views to a high-resolution autostereoscopic display for medical purposes. Displaying biomedical images on an autostereoscopic display poses different requirements than in a consumer case. For medical usage, it is essential that the perceived image represents the actual clinical data and offers sufficiently high quality for diagnosis or understanding. Autostereoscopic display of multiple views introduces two hurdles: transmission of multi-view data through a bandwidth-limited channel and the computation time of the volume rendering algorithm. We address both issues by generating and transmitting limited set of views enhanced with a depth signal per view. We propose an efficient view interpolation and rendering algorithm at the receiver side based on texture+depth data representation, which can operate with a limited amount of views. We study the main artifacts that occur during rendering—occlusions, and we quantify them first for a synthetic model and then for real-world biomedical data. The experimental results allow us to quantify the peak signal-to-noise ratio for rendered texture and depth as well as the amount of disoccluded pixels as a function of the angle between surrounding cameras.
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