Integration and visualization of multimodality brain data for language mapping.
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A goal of the University of Washington Brain Project is to develop software tools for processing, integrating and visualizing multimodality language data obtained at the time of neurosurgery, both for surgical planning and for the study of language organization in the brain. Data from a single patient consist of four magnetic resonance-based image volumes, showing anatomy, veins, arteries and functional activation (fMRI). The data also include the location, on the exposed cortical surface, of sites that were electrically stimulated for the presence of language. These five sources are mapped to a common MR-based neuroanatomical model, then visualized to gain a qualitative appreciation of their relationships, prior to quantitative analysis. These procedures are described and illustrated, with emphasis on the visualization of fMRI activation, which may be deep in the brain, with respect to surface-based stimulation sites. (+info)
Semi-automatic scene generation using the Digital Anatomist Foundational Model.
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A recent survey shows that a major impediment to more widespread use of computers in anatomy education is the inability to directly manipulate 3-D models, and to relate these to corresponding textual information. In the University of Washington Digital Anatomist Project we have developed a prototype Web-based scene generation program that combines the symbolic Foundational Model of Anatomy with 3-D models. A Web user can browse the Foundational Model (FM), then click to request that a 3-D scene be created of an object and its parts or branches. The scene is rendered by a graphics server, and a snapshot is sent to the Web client. The user can then manipulate the scene, adding new structures, deleting structures, rotating the scene, zooming, and saving the scene as a VRML file. Applications such as this, when fully realized with fast rendering and more anatomical content, have the potential to significantly change the way computers are used in anatomy education. (+info)
Mapping morphology of the corpus callosum in schizophrenia.
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The nature and extent of callosal morphological alterations in schizophrenia remain unresolved. A parametric surface modeling approach using magnetic resonance (MR) images was employed. This provided spatially accurate representations of midsagittal callosal surfaces in schizophrenic patients (n = 25; 15 males) and normal controls (n = 28; 15 males). Areas of functionally relevant callosal channels and measures reflecting callosal shape were visualized and compared across groups. To register neuroanatomical landmarks surrounding the corpus callosum, each three-dimensional MR volume was scaled according to Talairach AC-PC distance, and raw distances included as covariates in multivariate analyses. Results revealed: (i) a marked vertical displacement of the corpus callosum in patients (P < 0.01); (ii) increases in curvature of superior and inferior callosal surfaces (P < 0.001); and (iii) significant increases in maximum widths in anterior and posterior regions in male patients compared to male controls; as well as (iv) increased patterns of callosal variability in female patients but no effects of diagnosis between female groups. These findings demonstrate a clear index of structural neuropathology in male schizophrenic patients. Displacement and curvature increases were highly correlated with structural differences in surrounding neuroanatomical regions, including increased volume of the lateral ventricles (P < 0.01). (+info)
A three-dimensional model of the mouse at embryonic day 9.
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This paper describes a digital, three-dimensional model of the mouse embryo at E9. The model was made by reconstruction from images of serial histological sections digitally warped to remove distortions and has a resolution of approximately 9 microns. The model can be digitally resectioned in any plane to provide images which resemble conventional histological sections. The main tissues have been identified and delineated by digital painting so that the anatomical components can be visualized and manipulated in 3-D surface- and volume-rendered views. This provides a three-dimensional definition of anatomy that will provide a useful tool for interpreting and understanding spatial data in mouse embryos. The anatomy of the model is discussed where it provides landmarks for interpretation and navigation or where it is unexpected in light of existing descriptions of the E9 mouse embryo. The complete anatomy is not presented in this paper but will be available on CD-ROM. A detailed description of the technical aspects of the construction of the model is included in an appendix. The model is the first of a series that will form the basis for an atlas/database of mouse development. This reconstruction and its associated anatomy are available in a variety of data formats with some supporting software from http:@genex.hgu.mrc.ac.uk/. (+info)
Wall stress distribution on three-dimensionally reconstructed models of human abdominal aortic aneurysm.
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PURPOSE: Abdominal aortic aneurysm (AAA) rupture is believed to occur when the mechanical stress acting on the wall exceeds the strength of the wall tissue. Therefore, knowledge of the stress distribution in an intact AAA wall could be useful in assessing its risk of rupture. We developed a methodology to noninvasively estimate the in vivo wall stress distribution for actual AAAs on a patient-to-patient basis. METHODS: Six patients with AAAs and one control patient with a nonaneurysmal aorta were the study subjects. Data from spiral computed tomography scans were used as a means of three-dimensionally reconstructing the in situ geometry of the intact AAAs and the control aorta. We used a nonlinear biomechanical model developed specifically for AAA wall tissue. By means of the finite element method, the stress distribution on the aortic wall of all subjects under systolic blood pressure was determined and studied. RESULTS: In all the AAA cases, the wall stress was complexly distributed, with distinct regions of high and low stress. Peak wall stress among AAA patients varied from 29 N/cm(2) to 45 N/cm(2) and was found on the posterior surface in all cases studied. The wall stress on the nonaneurysmal aorta in the control subject was relatively low and uniformly distributed, with a peak wall stress of 12 N/cm(2). AAA volume, rather than AAA diameter, was shown by means of statistical analysis to be a better indicator of high wall stresses and possibly rupture. CONCLUSION: The approach taken to estimate AAA wall stress distribution is completely noninvasive and does not require any additional involvement or expense by the AAA patient. We believe that this methodology may allow for the evaluation of an individual AAA's rupture risk on a more biophysically sound basis than the widely used 5-cm AAA diameter criterion. (+info)
Going virtual with quicktime VR: new methods and standardized tools for interactive dynamic visualization of anatomical structures.
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Continuing evolution of computer-based multimedia technologies has produced QuickTime, a multiplatform digital media standard that is supported by stand-alone commercial programs and World Wide Web browsers. While its core functions might be most commonly employed for production and delivery of conventional video programs (e.g., lecture videos), additional QuickTime VR "virtual reality" features can be used to produce photorealistic, interactive "non-linear movies" of anatomical structures ranging in size from microscopic through gross anatomic. But what is really included in QuickTime VR and how can it be easily used to produce novel and innovative visualizations for education and research? This tutorial introduces the QuickTime multimedia environment, its QuickTime VR extensions, basic linear and non-linear digital video technologies, image acquisition, and other specialized QuickTime VR production methods. Four separate practical applications are presented for light and electron microscopy, dissectable preserved specimens, and explorable functional anatomy in magnetic resonance cinegrams. (+info)
Do oral appliances enlarge the airway in patients with obstructive sleep apnoea? A prospective computerized tomographic study.
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This study evaluated the effect of an anterior mandibular positioning appliance (AMPA) on minimum pharyngeal cross-sectional area (MPCSA) in 32 conscious supine obstructive sleep apnoea (OSA) subjects. The change in MPCSA was measured using low dose computerized tomography, with and without an AMPA in situ. The results showed that the mean presenting respiratory disturbance index (RDI) was 26.6 events/hour, with a body mass index of 28.6 kg/m2 and mean age of 51.5 years. There was a statistically significant increase in MPCSA of 28.34 mm2 on appliance insertion (SD = 59.06 mm2; range -145 to +190 mm2; P = 0.011). The mean mandibular displacement was 5.73 mm (SD = 2.51 mm) in protrusion and 8.27 mm (SD = 4.51 mm) inferiorly. A poor correlation was found between the size of the mandibular displacement and the change in MPCSA (protrusion r = 0.268; inferiorly r = 0.240, P > 0.05). In conclusion, the AMPA significantly increased MPCSA, suggesting that it may be an effective therapy for OSA. There was, however, a wide but unpredictable individual variation of response. As a small number of patients may worsen in their condition with temporary mandibular advancement (TMA), it is essential that all patients treated with TMA should be investigated by polysomnography both before and after treatment. (+info)
Virtual anatomy and movement of lower extremities using virtual reality modeling language.
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In medical imaging, the use of three-dimensional image is increasing for both educational and diagnostic purposes. With the advent of techniques for browsing a three-dimensional object, it became possible to display three-dimensional images on a personal computer via the Internet. This report describes the construction of a three-dimensional virtual model of human lower extremities that was linked with the data acquired from gait analysis in order to perform three-dimensional gait analysis. (+info)