Single Digital Image Research Articles

Image microarrays derived from tissue microarrays (IMA-TMA): New resource for computer-aided diagnostic algorithm development

Background: Conventional tissue microarrays (TMAs) consist of cores of tissue inserted into a recipient paraffin block such that a tissue section on a single glass slide can contain numerous patient samples in a spatially structured pattern. Scanning TMAs into digital slides for subsequent analysis by computer-aided diagnostic (CAD) algorithms offers the possibility of evaluating candidate algorithms against a near-complete repertoire of variable disease morphologies. This parallel interrogation approach simplifies the evaluation, validation, and comparison of such candidate algorithms. A recently developed pair of digital tools, digital core (dCORE),and image microarray maker (iMAM) enables the capture of uniformly sized and resolution-matched images, with these representing key morphologic features and fields of view, aggregated into a single monolithic digital image file in an array format, which we define as an image microarray (IMA). We further define the TMA-IMA construct as IMA-based images derived from whole slide images of TMAs themselves. Methods: Here we describe the first combined use of the previously described dCORE and iMAM tools, towards the goal of generating a higher-order image construct, with multiple TMA cores from multiple distinct conventional TMAs assembled as a single digital image montage. This image construct served as the basis of the carrying out of a massively parallel image analysis exercise, based on the use of the previously described spatially invariant vector quantization (SIVQ) algorithm. Results: Multicase, multifield TMA-IMAs of follicular lymphoma and follicular hyperplasia were separately rendered, using the aforementioned tools. Each of these two IMAs contained a distinct spectrum of morphologic heterogeneity with respect to both tingible body macrophage (TBM) appearance and apoptotic body morphology. SIVQ-based pattern matching, with ring vectors selected to screen for either tingible body macrophages or apoptotic bodies, was subsequently carried out on the differing TMA-IMAs, with attainment of excellent discriminant classification between the two diagnostic classes. Conclusion: The TMA-IMA construct enables and accelerates high-throughput multicase, multifield based image feature discovery and classification, thus simplifying the development, validation, and comparison of CAD algorithms in settings where the heterogeneity of diagnostic feature morphologic is a significant factor.

The Practical Application of a Flatbed Scanner for Air-Void Characterization of Hardened Concrete

Abstract Over the past 30 years, with the advent of computers and digital imaging, many automated systems have been introduced for the purpose of air-void characterization. The majority of the systems employs a contrast-enhancement procedure where a polished cross-section of concrete is darkened with paint, and white powder is forced into the depressions left by air-voids. The system described here follows the same approach and uses a flatbed scanner to collect a single digital image of the entire sample. For all of the systems based on contrast enhancement, the first step is to select a threshold level. Image pixels brighter than the threshold level represent air and image pixels darker than the threshold level represent non-air (i.e., paste or aggregate). Further digital processing steps may be employed but the initial selection of threshold level exerts a strong influence on whether a pixel in the final data set is classified as air or non-air. A systematic approach for threshold determination has been proposed based on an iterative procedure that compares automatically determined air-void parameters to manually determined air-void parameters from a set of training specimens. The calibration procedure finds a single optimum threshold level for the automated system that is to be used for all subsequent analyses. The approach was tested on a population of 88 specimens with manually determined air-void parameters, with the goal of determining an appropriate value for the number of training specimens.

A Photogrammetric Method for Single Image Orientation and Measurement

The aim of this paper is to present a photogrammetric method for determining the dimensions of flat surfaces, such as billboards, based on a single digital image. A mathematical model was adapted to generate linear equations for vertical and horizontal lines in the object space. These lines are identified and measured in the image and the rotation matrix is computed using an indirect method. The distance between the camera and the surface is measured using a lasermeter, providing the coordinates of the camera perspective center. Eccentricity of the lasermeter center related to the camera perspective center is modeled by three translations, which are computed using a calibration procedure. Some experiments were performed to test the proposed method and the achieved results are within a relative error of about 1 percent in areas and distances in the object space. This accuracy fulfills the requirements of the intended applications.

Three-Dimensional Photography and Its Application to Facial Plastic Surgery

Photography is integral to the practice of facial plastic surgery. We describe a new 3-D photographysystem,the3dMDfaceSystem(3dMD,Atlanta,Ga),whichprovidesahighresolution 3-D image that can be viewed from any angle; has the ability to accurately measure surface distance, area, and volume; and performs profile adjustments that can be viewed in 3 dimensions. We describe specific applications of this system to facial plastic surgery, namely, to that of the aging face.

Combined structural and functional imaging of the breast.

Scintimammography, or single gamma nuclear imaging of the breast, has shown promise as a way of characterizing certain biological properties of suspicious breast masses. Conventional scintimammography, performed using large clinical gamma cameras and prone patient positioning suffers from several drawbacks including poor sensitivity for small (> 1 cm) lesions and no reliable method for correlating scintigraphic findings with those of other imaging modalities. We are developing a system designed to overcome some of these problems. The system combines x-ray mammography with scintimammography on a common gantry. The x-ray and gamma ray images are obtained in quick succession, with the breast in a common configuration under mild compression. A digital x-ray detector is used, permitting rapid assessment of lesion location prior to gamma imaging, and enabling fusion of the x-ray transmission and gamma emission information in a single digital image. In a pilot clinical diagnostic study, the system has demonstrated high pathology-proven accuracy in differentiating benign and malignant masses.

Digital photographic screening for diabetic retinopathy in the James Bay Cree

This study evaluates a single, 45-degree fundus image from a non-mydriatic camera for the triage of subjects at risk for diabetic retinopathy. A complete retinal assessment by a retina specialist was the main comparator for the camera. Inter-observer agreements were calculated for the reading of digital images with different grades of retinopathy. Two hundred eyes of 100 consecutive subjects were evaluated as part of the James Bay diabetic retinopathy screening project; 62% of subjects had no retinopathy, 12% had microaneurysms only, 24% had non-proliferative retinopathy, 5% had clinically significant macular edema (CSME), and 2% had proliferative disease (PDR). The Kappa statistic for two independent observers was 0.85 (p < 0.001) for the identification of retinopathy from the digital images. The sensitivity of the digital camera for the evaluation of any retinopathy was 84.4%, for CSME and/or PDR it was over 90%. The use of a single digital retinal image for the evaluation of diabetic retinopathy was performed with a high degree of inter-observer concordance and a high degree of sensitivity.

Image-sequence motion estimation for the Dervish mine-clearance vehicle

The paper reports on the application of block matching with spatial transforms to image sequences of ground scenes taken from a moving camera. The motion is a general combination of rotation and translation. The use of spatial transforms with interpolation filtering to generate rotation reference templates and the hardware implementation, for use on a robot mine-clearance vehicle, are novel. It is shown that the emerging generation of single chip floating-point digital signal processors and CMOS image sensors are well suited to rapid prototyping of image sequence analysis, which has previously been the domain of expensive camera and custom VLSI hardware or cumbersome parallel machines.

Bone atrophy at high altitude

The bone metabolism in high mountaineering was investigated. The bone densities of 24 members of Himalayan expedition parties were measured before and after expedition by single photon absorptiometry and digital image processing method. As a result, decrease of bone density of 1/6 radial distal portion was 3.2±5.4% (p<0.01). The bone atrophy tended to recover in 5 months and 12 months follow-up measurement, but did not recover completely in a year. Among the indices of bone metabolism, moreover, serum Ca and 1,25-(OH)2D3 decreased of 4.5±4.1% and 22.4±21.9% respectively, during the Himalayan expedition. Concerning the nutritional state, 4.5±4.0% decrease of body weight was observed, but the serum cholesterol was increased of 12.6±14.8%, and this fact could not be explained by malnutrition alone. The special environment of high mountain, that is, low barometric pressure and low oxygen tension, is probably responsible for the bone atrophy.