Biomedical subjects

W E Higgins

Publications and source records attributed to W E Higgins.

7 recordsLinked to original sources

PubMed2000

Extraction of the hepatic vasculature in rats using 3-D micro-CT images.

High-resolution micro-computed tomography (CT) scanners now exist for imaging small animals. In particular, such a scanner can generate very large three-dimensional (3-D) digital images of the rat's hepatic vasculature. These images provide data on the overall structure and function of such complex vascular trees. Unfortunately, human operators have extreme difficulty in extracting the extensive vasculature contained in the images. Also, no suitable tree representation exists that permits straight-forward structural analysis and information retrieval. This work proposes an automatic procedure for extracting and representing such a vascular tree. The procedure is both computation and memory efficient and runs on current PCs. As the results demonstrate, the procedure faithfully follows human-defined measurements and provides far more information than can be defined interactively.

Angiography↗

PubMed1999

Interactive dynamic navigation for virtual endoscopy.

Complex anatomical information can be obtained from a 3D radiologic image by navigating through it in a manner similar to an endoscopic examination. Real-time computation of 'virtual' endoscopic views, however, is needed to permit interactive navigation. We present a fast volume-rendering method for computing such views. Our method, motivated by the temporal-coherence concept, performs dynamic volume rendering at interactive frame rates. Results demonstrate the method's efficiency and accuracy. Also, our method constitutes part of a complete virtual-endoscopic system we have devised. This system is illustrated for 3D pulmonary analysis.

Algorithms↗

PubMed1997

Distributed system for processing 3D medical images.

Three-dimensional (3D) image data generated by radiological imaging modalities such as CT and MRI can provide detailed structural insight. Automating the analysis of these images can improve the consistency of the results and reduce user interaction time, but introduces a tremendous computational burden. To address this problem, we have designed a distributed processing environment for the rapid processing of 3D medical images. Our system allows a user to perform automatic 3D filtering, segmentation, and measurement on a 3D image using a heterogeneous network of processors and the PVM protocol.

Computer Communication Networks↗

PubMedDate not supplied

LV chamber extraction from 3-D CT images--accuracy and precision.

Measurement of left ventricular (LV) chamber volume and shape from three-dimensional (3-D) CT images, generated by the fast X-ray CT scanner known as the dynamic spatial reconstructor, has previously been done using manual slice-image editing. To reduce the exorbitant operator analysis time and operator-dependent measurement variations of manual slice-image editing, we have devised a semiautomatic method for LV-chamber extraction. The method draws upon a minimum requirement for selective manual slice-image editing and mostly makes use of automatic image-analysis operations. Detailed validation results over a wide range of hemodynamic and image-analysis conditions show that the measurements of the semiautomatic method strongly correlate with those made via manual slice-image editing and exhibit a lower intertrial variability. Further, the method reduces operator interaction time by nearly an order of magnitude over that of manual slice-image editing, but provides more detailed 3-D structural definition.

Animals↗

PubMedDate not supplied

Interactive morphological watershed analysis for 3D medical images.

Combining automatic processing with interactive techniques is proving to be an effective strategy for segmenting complex three-dimensional (3D) medical images. We describe a general 3D image segmentation strategy that draws upon morphological watershed analysis and operator-defined topological cues. Watershed analysis segments a gray scale image into different regions by interpreting the image as a topographic surface. Using readily available interactive techniques, a human operator can easily define cues that specify spatial relationships between regions of interest. Cues defined in such a manner greatly assist subsequent watershed analysis. Results using 3D cardiac images show that this method leads to rapid robust image segmentation.

Algorithms↗

PubMedDate not supplied

IMPROMPTU: a system for automatic 3D medical image-analysis.

The utility of three-dimensional (3D) medical imaging is hampered by difficulties in extracting anatomical regions and making measurements in 3D images. Presently, a user is generally forced to use time-consuming, subjective, manual methods, such as slice tracing and region painting, to define regions of interest. Automatic image-analysis methods can ameliorate the difficulties of manual methods. This paper describes a graphical user interface (GUI) system for constructing automatic image-analysis processes for 3D medical-imaging applications. The system, referred to as IMPROMPTU, provides a user-friendly environment for prototyping, testing and executing complex image-analysis processes. IMPROMPTU can stand alone or it can interact with an existing graphics-based 3D medical image-analysis package (VIDA), giving a strong environment for 3D image-analysis, consisting of tools for visualization, manual interaction, and automatic processing. IMPROMPTU links to a large library of 1D, 2D, and 3D image-processing functions, referred to as VIPLIB, but a user can easily link in custom-made functions. 3D applications of the system are given for left-ventricular chamber, myocardial, and upper-airway extractions.

Computer Graphics↗

PubMedDate not supplied

Virtual bronchoscopy for three--dimensional pulmonary image assessment: state of the art and future needs.

Virtual bronchoscopy is emerging as a useful approach for assessment of three-dimensional (3D) computed tomographic (CT) pulmonary images. A protocol for virtual bronchoscopic assessment of a 3D CT pulmonary image would have two main stages: (a) preprocessing of image data, which involves extracting objects of interest, defining paths through major airways, and preparing the extracted objects for 3D rendering; and (b) interactive image assessment, which involves use of graphics-based software tools such as surface-rendered views, projection images, virtual endoscopic views, tube views, oblique section images, measurement data, global two-dimensional section images, and cross-sectional views. Although a virtual bronchoscope offers a unique opportunity for exploration and quantitation, it cannot replace a real bronchoscope. Limitations of current virtual endoscopy systems include high cost, lack of visual aids beyond simulated endoscopic views, difficulty in performing interactive anatomic exploration, lack of quantitative information, use of surface rendering instead of volume rendering, and need for substantial off-line display computation. Future needs include development of fully integrated user-friendly virtual bronchoscopes, development of optimal CT protocols for generating artifact-free data sets, and improvements in automated preprocessing of 3D CT images.

Bronchoscopy↗