Object-oriented design of medical imaging software

The anteromedial facet of the coronoid process of the ulna

Fracture of the anteromedial facet of the coronoid process has been recognized as an important type of coronoid fracture. We performed a quantitative analysis of 21 3-dimensional computed tomography scans to evaluate the degree to which the anteromedial facet protrudes as a distinct process separate from the proximal ulnar metaphysis. The distance between the center axis of the trochlear notch and the most medial edge of the anteromedial facet averaged 12.5 mm (range, 8.7-20.1 mm). The part of the maximum anteromedial facet width that was supported by the proximal ulnar metaphysis and diaphysis averaged 5.4 mm (range, 1.7-11.5 mm). On average, 58% of the anteromedial facet (range, 26%-82%) was unsupported by the proximal ulnar metaphysis and diaphysis. It is not surprising that this relatively vulnerable protrusion from the anteromedial facet of the coronoid is frequently a separate fracture fragment in complex traumatic elbow instability.

Coronoid fracture height in terrible-triad injuries

PURPOSE

The coronoid fractures that occur in the terrible-triad pattern of traumatic elbow instability (posterior dislocation with fractures of the radial head and coronoid) usually are small transverse fragments. Attempts to classify these fragments according to height as suggested by Regan and Morrey have been inconsistent and contentious. The purpose of this study was to quantify coronoid fracture height in terrible-triad injuries.

METHODS

The height of the coronoid process of the ulna and the coronoid fracture fragment were measured on computed tomography scans of 13 patients with terrible-triad-pattern elbow injuries. Two observers performed the measurements with excellent intraobserver and interobserver reliability.

RESULTS

The total height of the coronoid process of the ulna averaged 19 mm. The average height of the coronoid fracture fragment was 7 mm. This corresponds to an average of 35% of the total height of the coronoid process.

CONCLUSIONS

The transverse coronoid fractures associated with terrible-triad elbow injuries have a variable height that may not be easy to classify according to the system of Regan and Morrey. Classification of coronoid fractures according to fracture morphology and injury pattern may be preferable.

[Development of an image processing scheme for chest radiographs using a dot printer]

The performance of dot printers has recently been improved. Images output by dot printers can provide simple, economical medical reference images if important diagnostic information is not lost. We developed an image processing scheme for chest radiographs that employed a dot printer. We used two types of pixel value conversions, a nonlinear pixel value correction using a lookup table and a linear pixel value conversion using histogram analysis. The density distribution of chest radiographs was analyzed and classified into high-density and low-density images. The two types of pixel value conversions were used depending on the density of chest radiographs. Converted pixel value had density characteristics that were adapted to the output image of the dot printer, and thus the density distributions of the lungs of radiographs became comparable. In addition, an adaptive unsharp masking technique with processing parameters optimized for each of the lungs and mediastinum was applied. An ROC study for the detection of lung nodules was carried out to evaluate the performance of dot printer images. The area under the ROC curve (A(z)) for dot printer images was 0.816, while sensitivity and specificity were 77.6% and 75.2%, respectively. The performance indicated the usefulness of our image processing scheme.

Software for efficient visualization and analysis of multiple, large, multi-dimensional data sets from magnetic resonance imaging

Comprehensive magnetic resonance imaging (MRI) protocols create multiple, large, multi-dimensional data sets that are challenging to review and interpret in an efficient manner. We report on a program called CliniViewer that uses a common data file format to display all files originating from the scanner and other post-processing programs in an integrated display matrix. The five rows of images and maps have general themes of Anatomic Images, Echo-Planar Images, Parametric Maps (derived from echo-planar images), Metabolic Images, and Non-Image Data, respectively. Each row of the matrix contains related image windows of individual MR acquisitions or maps derived from such acquisitions.An interpreter can quickly screen all images and then select any image from the display to create a separate daughter window incorporating a set of analysis tools for in-depth examination. Given that the images can be acquired in the same co-registered planes without moving the subject, regional analysis can be performed simultaneously across multiple MR image types and the corresponding maps, thereby integrating anatomic features with parametric properties. Color can be used to highlight parametric values that fall outside normal ranges to quickly identify abnormalities on each map. CliniViewer is an efficient environment for analyzing multiple images and maps from comprehensive clinical imaging protocols, aiding the neuroradiologist in providing an integrated interpretation of all available MR data for efficient clinical decision making. CliniViewer is compared to AnalyzeAVW and NIH Image, two popular MR image analysis tools. CliniViewer allows efficient clinical analysis of multiple images and maps from comprehensive clinical imaging protocols.

A simple image analysis method for evaluating cell binding to derivatized beads

We have previously developed a novel method to determine the presence or absence of cell surface lectin receptors using derivatized agarose beads and have used many different derivatized beads in examining other cell surface properties. Thus, we have used beads that were previously utilized mainly for chromatography purposes in a new approach to study cell surface histochemistry. The previous studies analysed cell-bead binding using subjective plus-minus descriptions that suffered from lack of quantification. We needed a quantitative method in this new approach for histochemical cell surface studies. Here we describe a new method using image analysis of photographs that we developed to solve the quantification problem. The histogram feature of Adobe Photoshop was used to analyse cell binding to beads that were isolated by computer. The method is simple and works as more cells bind to the beads, the beads appear darker in color, a feature easily and precisely quantified using Adobe Photoshop.

A hierarchical model for PACS

In this paper, a hierarchical model for Picture Archiving and Communication Systems (HPACS) is presented and implemented at Taichung Veterans General Hospital (TCVGH) in Taiwan. Despite the fact that the HPACS is built on the architecture of the second generation PACS, it offers many improved features and has advantages over the second generation PACS, such as the user security control, fast resource dispatch and efficient resource management. This HPACS can be used as a reference model for a hospital with any scale-size. The real implementation of HPACS is currently undertaken in the Taichung Veterans General Hospital (TCVGH), Taiwan, Republic of China and consists of four phases with the first two phases already completed. It is the first pilot system ever to be implemented successfully in a large-scale hospital in Taiwan. The experiences have illustrated the great promise of the HPACS in the future.

A medical workstation for the display and analysis of multi-frame digital cineradiographic data

A medical workstation has been developed for the efficient display and analysis of large sets of digital cineradiographic images. Various features aid the clinician in quickly identifying and extracting the image information relevant for diagnosis: animated viewing of image frames, a digital magnifying glass for local image enlargement and enhancement, a special review queue for critical image frames, and task-oriented image processing. Double frame buffering and direct memory addressing ensure fast, artifact-free image display and transfer. Much freedom is provided for adapting the system to one's own preferences. A statistical analysis of extensive tests conducted by eight clinical expert reviewers is given.