Edward J. Farrell

Color display and interactive interpretation of three-dimensional data

Three-dimensional results from engineering and scientific computations often involve the display and interpretation of a large volume of complex data. A method is developed for color display of 30 data with several interactive options to facilitate interpretation. The method is based on representing points whose values fall within a specified range as a single hue. An image is formed by overlaying successive 2D frames with increasing hue lightness towards the front. Interactive options to aid interpretations are viewpoint, contour lines, multiple range display, slicing, veiled surfaces, and stereo image pairs. The display method is successfully applied to several types of data. The overall structure and variations of the 30 data are observable, as well as transients which may be overlooked in a large input data set.

Color 3-D Imaging of Normal and Pathologic Intracranial Structures

The overall feasibility of 3-D imaging for intracranial soft tissues depends on three vital areas: the display method,the display options, and the image processing system.

Animated 3D CT Imaging

A new display-system approach uses 3D animation to enhance the viewers spatial perception of patient scan data.

Quantifying the need for cardiac support in human shock by a functional model of cardiopulmonary vascular dynamics: with special reference to myocardial infarction

Abstract A quantitative method of analyzing cardiac and pulmonary vascular dynamics has been developed on the basis of a functional model of central indicator dilution. Using this model it has been possible to demonstrate a segregation of patients with various clinical states by virtue of the quality of their dynamic cardiac mixing. Patients with hyperdynamic states secondary to sepsis or cirrhotic liver disease show rapid cardiac mixing times ( t m ), unless there is evidence of myocardial failure when a prolongation of mixing time occurs, even at high cardiac outputs. Patients with myocardial infarction (MI) shock have very prolonged cardiac mixing times. A critical level of t m has been established for MI shock patients, at which some form of mechanical cardiac support seems mandatory if patient salvage is to be possible. A group of MI shock patients has been identified who also show evidence for a significant cardiac nonmixing volume which appears associated with the magnitude of the akinetic area of infarcted myocardium. The appearance of such a cardiac nonmixing volume appears to be an important prognostic sign which suggests the need for cardiac support and may also have implications regarding the necessity for definitive surgery. The dvnamic aspects of pulmonary volume shifts with changing myocardial contractile states can also be inferred from the quantitative model. A technique of estimating the important model parameters at the bedside is described which can be applied as a guide to assist the surgeon in patient management.

Investigation of cardiorespiratory abnormalities through computer simulation.

Abstract The basic physiologic functions which were simulated on the digital computer are multiple alveolar ventilation through a branching bronchial structure, the distribution of alveolar ventilation across the lung based on airway resistance and alveolar compliance, O2 and CO2 exchange with and transport in the blood, ventilation control based on arterial blood Pa co 2, Pa o 2 and pHa, and peripheral metabolic exchange of O2, CO2, and acid or base. The simulation output is a set continuous-time variables corresponding to clinical measurements, namely: volume, rate and composition of expired gas, composition of arterial and venous blood, indicator dilution across the heart and lung, and intraplural pressure used to obtain dynamic lung compliance and resistance. The simulation was used to investigate the observability (based on the clinical measurements) of changes in ventilation and perfusion distributions and to evaluate the ability of the lung to control acid-base balance with normal and reduced lung compliance for a range of metabolic CO2 production and acid or base, compatible with those observed in critically ill patients in decompensated septic shock.

Complementary visualization and sonification of multidimensional data

Interpretation of multi-dimensional complex data usually involves extracting the relationship between several variables. This is typically done with an interactive visual system . Iugh resolution volumetric data imaging, color, animation, and multiple views are effective tools for data interpretation. Sound can provide an additional and complementary perceptual channel. This presentation focuses on the use of sound with a multi-dimensional imaging system to facilitate the interactive interpretation of complex data. Our methods and system are presented with data from a simulation which computes electron density, hole density, and potential throughout the volume of a three-dimensional semiconductor. The spatial changes and relationships of the three scalar fields are the object of study. Normally the field relations would he examined through multiple visualizations. here, sound is used to augment the visualization by permitting a user to visually concentrate on one field, while listening to the other. Two of the three scalar fields from the simulation arc selected for interpretation and visualized. The 3-dimensional vector gradient of one of them is sonified at a selected focal point within the semiconductor solid. As the current focus i interactively moved through the solid, the representative sound is altered accordingly. The sonification is composed such that local minima and maxima of one of the fields can he found without looking at it.

Graphical 3D Medical Image Registration and Quantification

We present a graphical three-dimensional method that facilitates image registration and fusion, and provides quantitative geometric and volume information. In particular it enhances the use of functional (radiopharmaceutical) imaging (SPECT, PET) which, though a powerful clinical tool, has the disadvantage of low spatial resolution and ill-defined boundaries. Registration between functional images and structural images (MRI, CT) can augment the anatomical context of these functional images.

Animation and 3D color display of multiple-variable data: application to semiconductor design

The increasing complexity of digital simulations requires more effective techniques to display and interpret the voluminous outputs. Advanced digital processing workstations and high-resolution color monitors permit a wide range of new techniques for use in examining the global characteristics of each output variable and their interrelationships with other variables. In this investigation, animation, 3D display, and multiple-window imaging have been shown to be effective in interpreting multiple-variable data sets, both scalar and vector. These display methods are used in the solution of two specific semiconductor design problems: the avalanche breakdown of an n-MOSFET and an alpha particle hit on an npn transistor. With these techniques the user can more fully utilize the results of these long and costly computations, making these methods a powerful addition to existing techniques for imaging data.

Visualization Of Complex Data

Large-scale simulations and scientific measurements often produce complex multi-dimensional data sets. To fully utilize the results of costly computations and measurements effective visualization methods are required to interpret the data.1, 2, 3 Prior methods based on contour plots, mesh surfaces, or titled structures are not adequate. Structure modeling does not have the capacity needed for display and interpretation; data interpretation is more complex than every day vision. The user may wish to visualize a nebulous 3D region, data without distinct surfaces or structures, or a region buried inside a larger structure, or interrelate 3D regions in different data sets.

Planning Neurosurgery wiih Interactive 3D Computer Imaging

Planning intracranial neurosurgery involves understanding the threé-dimensional interrelationships of normal and pathologic structures, and contrasting alternate surgical approaches. The present study demonstrates the usefulness of interactive 3D imaging of CT data for surgical planning. Imaging options allow the surgeon to manipulate structures, obtain quantitative data on spatial relations, and contrast alternate surgical approaches based on 3D images similar to what is seen during surgery. The surgeon can choose the surgical approach that permits the best tumor exposure with minimal disruption of neural structures.