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Results for “Image Interpretation, Computer-Assisted”

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PubMed1992

[The value of digital luminescence radiography within the scope of traumatologic follow-up examinations].

At the present time we cannot unhesitatingly recommend the general use of digital luminescence radiography in traumatological follow-up examinations. Marked drawbacks of this method are, for example, sudden changes in contrast in the marginal areas of osteosynthesis material, occasional limitations in the detailed assessment of spongious structures and problems in respect of imaging geometry. By modifying the image processing parameters, increasing the image matrix and enlarging the format spectrum, however, these problems should be capable of being resolved in the future. Positive features, on the other hand, are even now the possibility of reducing the dosage to a marked degree in many traumatological follow-up examinations, especially in children and adolescents, and in case of conservatively treated fractures. In the long run we can foresee the routine use of digitalised examination methods on traumatology coupled with the possibility of storage in an image filing and communication system, although this is at present not yet feasible due to lack of requisite experience and the cost of the necessary equipment.

Computer Systems↗

PubMed1992

New metrics for analysis of dendritic branching patterns demonstrating similarities and differences in ON and ON-OFF directionally selective retinal ganglion cells.

The morphology and dendritic branching patterns of retinal ganglion cells have been studied in Golgi-impregnated, whole-mount preparations of rabbit retina. Among a large number of morphological types identified, two have been found that correspond to the morphology of ON and ON-OFF directionally selective (DS) ganglion cells identified in other studies. These two kinds of DS ganglion cell are compared with each other, as well as with examples of class I, class II, and class III cells, defined here with reference to our previous studies. Cell body, dendritic field size and branching pattern are analyzed in this paper and levels of dendritic stratification are examined in the following paper. ON DS ganglion cells are about 10% larger in soma size and about 5 times the dendritic field area of ON-OFF DS ganglion cells, when compared at the same retinal location. These two morphological types of ganglion cell can be said to define the upper and lower bounds of an intermediate range of cell body and dendritic field sizes within the whole population of ganglion cells. Nevertheless, in previous physiological studies receptive field sizes of the two types were shown to be similar. This discrepancy between morphological and physiological evidence is considered in the Discussion in terms of a model of the excitatory receptive field of ON-OFF DS ganglion cells incorporating starburst amacrine cells. A new set of metrics is introduced here for the quantitative analysis and characterization of the branching pattern of neuronal arborizations. This method compares the lengths of terminal and preterminal dendritic branches (treated separately), as a function of the distances of their origins from the soma, viewed graphically in a two-dimensional scatter plot. These values are derived from computer-aided 3D logging of the dendritic trees, and distance from the soma is measured as the shortest distance tracked along the dendritic branches. From these metrics of the "branch length distributions," scale-independent branching statistics are derived. These make use of mean branch lengths and distances, slopes of lines fitted to the distributions, and elliptical indices of scatter in the distributions. By these measures, ON and ON-OFF DS ganglion cells have similar branching patterns, which they share to varying degrees with functionally unrelated class III.1 ganglion cells. The scale of the branching patterns of ON and ON-OFF DS cells and their degree of uniformity are different, however.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed2026

Integrating histology and spatial transcriptomics via multimodal transformers and contrastive representation learning for accurate gene expression prediction.

Predicting spatial gene expression from Histological images is a fundamental task in understanding tissue organization and molecular phenotypes. However, existing methods often rely on single-model representations or lack effective alignment between image and transcriptomic features. To address these limitations, we propose a unified multimodal learning framework that integrates histological imaging and spatial transcriptomics through a shared latent representation space. Specifically, histological H&E images are encoded by a ResNet50-based convolutional stem and a MobileViT Transformer backbone to extract hierarchical visual representations. Both modalities are projected into a shared latent space via linear-GELU-dropout transformation blocks, enabling cross-modal alignment through a contrastive learning objective that maximizes agreement between the corresponding image and the spot embeddings. Experimental results on the 10x Genomics Visium dataset of human liver tissue demonstrate that MViTGene achieves significantly higher prediction accuracy than existing methods across multiple gene subsets, with improvements of 20%, 33%, and 12% in predicting marker genes, highly expressed genes, and highly variable genes, respectively. The significant improvement in relevance indicates that the model can more accurately capture the true correspondence between tissue morphology and gene expression, therefore enabling more reliable biological interpretation. It provides a computational tool for high-throughput spatial gene expression prediction that balances performance and interpretability.

Humans↗

PubMed1992

A two-step alignment method for 3D computer-aided reconstruction based on fiducial markers and applied to mouse embryonic hearts.

An accurate three dimensional computer reconstruction of microscopic biological objects or distribution of molecules identified on serial sections must solve two major problems: 1) the alignment of sections using adequate extrinsic references (fiducial markers); 2) the impossibility of observing these references and the cellular or molecular structures in the microscope at the same magnification. To provide extrinsic references for objects embedded in soft media, we have modified and simplified the charcoal-paraffin method described by Langemeijer and Simons (1973). It consists of drilling three or four small holes into the paraffin block, sealing this block at the extremity of a glass holder and, from the other extremity of the holder attached to a rubber hose, aspirating a liquefied mixture of charcoal-paraffin to fill these cylindrical holes. An alignment procedure was developed using serial sections of mouse embryonic hearts with bromodeoxyuridine-labelled DNA synthesizing cells. From each fourth section, two sets of contours have been drawn and digitized: 1) at low magnification (about 40x), embryo body wall, heart, neural tube and extrinsic reference marks (black dots); 2) at higher magnification (240-300x): heart contours alone (without extrinsic references, but with individual labelled cells). Different operations of the computer-aided alignment, as well as checking of results by inverse alignment, are described in detail. This two-step alignment method offers a practical, efficient compromise between: a) purely subjective alignment based only on tissular landmarks interpreted by the operator; b) ideal perfect alignment based not only on adequate references, but on computerized correction of section deformation, as well.

Animals↗

PubMed1992

Focal liver lesions: MR imaging with Mn-DPDP--initial clinical results in 40 patients.

Manganese (II) N,N'-dipyridoxylethylenediamine-N,N'-diacetate-5,5'-bis(phosphate) (DPDP) was evaluated as a contrast agent for magnetic resonance (MR) imaging (1.5 T) of focal liver lesions in 40 patients. Doses of 5 and 10 mumol/kg were administered intravenously. Mn-DPDP-enhanced T1-weighted images were compared quantitatively and subjectively with standard T1- and T2-weighted nonenhanced images. Use of Mn-DPDP resulted in a statistically significant increase in signal intensity of liver parenchyma in T1-weighted images at both doses. No enhancement was seen in metastases, cholangiocarcinomas, or lymphomas, while all hepatocellular carcinomas were enhanced. Enhancement was seen in focal nodular hyperplasia and in regenerative nodules. The lesion-to-liver contrast in Mn-DPDP-enhanced gradient-recalled-echo images was superior to that of all precontrast images (P less than .01). The number of nonenhancing malignant liver lesions detected in spin-echo (SE) images was increased (272 in T2-weighted SE images vs 390 in T1-weighted Mn-DPDP-enhanced SE images). Image interpretation (eg, visualization and demarcation of the lesions) was markedly better in Mn-DPDP-enhanced images than in all precontrast images (P less than .001).

Adult↗

PubMed1992

Three-dimensional crystallographic reconstruction for atomic resolution.

Three-dimensional structures have recently been determined by electron crystallography at a resolution high enough to determine atomic arrangements in both protein and mineral specimens. The different nature of these two types of specimens produces some very significant differences in the way data is obtained and processed, although the principles are the same. The sensitivity of proteins to damage by the electron beam limits the signal-to-noise ratio in the image and the resolution to which data can be extracted from the image. A number of constraints, such as the amino acid sequence and the connectivity of atoms within amino acids, can be used in interpreting the limited image data. In materials samples, the relative insensitivity to damage allows obtaining resolution limited only by the microscope. In many samples, dynamical scattering and other non-linear effects limit the information in the image, but this limit can be circumvented by working in very thin areas of the specimen.

Bacteriorhodopsins↗

PubMed1992

Computer-aided analysis of DNA curves on transverse gradient gels.

Transverse pore gradient polyacrylamide gel electrophoresis of DNA restriction fragments was used to generate gel patterns describing migration distance as a function of gel concentration (Ferguson curves). These Ferguson curves were digitized, traced and analyzed with the aid of a personal computer. The traced curves were plotted semi-logarithmically and the plots were subjected to least-squares linear regression analysis to yield values of the slope (KR) and the intercept at %T = 0 (YO). These values are highly precise since they are based on approx. 100 measurements per curve. The computerized method reduces the errors due to manual measurements of migration distances and is time and labor saving. The method is still limited to intra-experimental comparison of Ferguson curves, since it does not as yet comprise a determination of gel concentration. At present, curve tracing remains semi-automated, requiring manual intervention when Ferguson curves cross or approach one another. Potentially, the importance of the computerized analysis of transverse pore gradient gels lies in the rapid quantitative interpretation of Ferguson curves for detection of anomalously migrating DNA species. Potentially, that application provides a more sensitive and informative mode of detection than either the mere visual observation of crossing Ferguson curves or of a shift in mobility at a single gel concentration.

Buffers↗

PubMed1976

[Theory of image discernment and resolution of classification problems using medico-psychological methods].

The report deals with questions pertaining to the use of the theory of image discernment for solving psychodiagnostical problems in clinical practice. The traditional understanding of a psychological test as a measurement instrument is being opposed to its new interpretation as an instrument of classification. On this basis the authors described the successional stages of the general procedure in the elaboration of tests. Special attention is being drawn to the selection of primary signs with the aid of informational measures and the formation of scales as discriminators. The suggested approach is being illustrated on the model of elaborating scales of a personality questionnaire and intellectual techniques.

Diagnosis, Computer-Assisted↗

PubMed2020

Chemical Imaging of Retinal Pigment Epithelium in Frozen Sections of Zebrafish Larvae Using ToF-SIMS.

Variants of the SLC24A5 gene, which encodes a putative potassium-dependent sodium-calcium exchanger (NCKX5) that most likely resides in the melanosome or its precursor, affect pigmentation in both humans and zebrafish (Danio rerio). This finding suggests that genetic variations influencing human skin pigmentation alter melanosome biogenesis via ionic changes. Gaining an understanding of how changes in the ionic environment of organelles impact melanosome morphogenesis and pigmentation will require a spatially resolved way to characterize the chemical environment of melanosomes in pigmented tissue such as retinal pigment epithelium (RPE). The imaging mass spectrometry technique most suited for this type of cell and tissue analysis is time-of-flight secondary ion mass spectrometry (ToF-SIMS) because it is able to detect many biochemical species with high sensitivity and with submicron spatial resolution. Here, we describe chemical imaging of the RPE in frozen-hydrated sections of larval zebrafish using cryo-ToF-SIMS. To facilitate the data interpretation, positive and negative polarity ToF-SIMS image data were transformed into a single hyperspectral data set and analyzed using principal component analysis. The combination of a novel protocol and the use of multivariate data analysis allowed us to discover new marker ions that are attributable to leucodopachrome, a metabolite specific to the biosynthesis of eumelanin. The described methodology may be adapted for the investigation of other classes of molecules in frozen tissues from zebrafish and other organisms.

Animals↗

PubMed2024

Digital pathology and spatial omics in steatohepatitis: Clinical applications and discovery potentials.

Steatohepatitis with diverse etiologies is the most common histological manifestation in patients with liver disease. However, there are currently no specific histopathological features pathognomonic for metabolic dysfunction-associated steatotic liver disease, alcohol-associated liver disease, or metabolic dysfunction-associated steatotic liver disease with increased alcohol intake. Digitizing traditional pathology slides has created an emerging field of digital pathology, allowing for easier access, storage, sharing, and analysis of whole-slide images. Artificial intelligence (AI) algorithms have been developed for whole-slide images to enhance the accuracy and speed of the histological interpretation of steatohepatitis and are currently employed in biomarker development. Spatial biology is a novel field that enables investigators to map gene and protein expression within a specific region of interest on liver histological sections, examine disease heterogeneity within tissues, and understand the relationship between molecular changes and distinct tissue morphology. Here, we review the utility of digital pathology (using linear and nonlinear microscopy) augmented with AI analysis to improve the accuracy of histological interpretation. We will also discuss the spatial omics landscape with special emphasis on the strengths and limitations of established spatial transcriptomics and proteomics technologies and their application in steatohepatitis. We then highlight the power of multimodal integration of digital pathology augmented by machine learning (ML)algorithms with spatial biology. The review concludes with a discussion of the current gaps in knowledge, the limitations and premises of these tools and technologies, and the areas of future research.

Humans↗

PubMed1978

Dual radionuclide study of acute myocardial infarction: comparison of thallium-201 and technetium-99m stannous prophosphate imaging in man.

We evaluated dual imaging with thalium-201 (201TI) and technetium-99m (99mTc) pyrophosphate in 80 patients with documented acute myocardial infarction (55 transmural, 25 nontransmural infarction). Color-coded isocount display of 201TI images was essential for interpretation in 16 patients. Combined 201 TI and 99mTc-pyrophosphate imaging for infarct detection was 100% sensitive; however, either was falsely negative in 12 of 80 patients. False-negative individual 201TI or 99mTc-pyrophosphate infarct images were most common in patients with small infacts or left ventricular hypertrophy. Thallium-201 images correctly localized the site of acute transmural infarction in all 51 patients with a positive image, while 99mTc-pyrophosphate localized the site of infarction in 49 of 53 with an abnormal image. Comparison of the size of the imaged infarct region revealed size discordance in 25 of 49 patinets, with 99mTc-pyrophosphate larger in 21 of 49 and 201TI larger in only four of 49. Thus dual radionuclide imaging provides definition of the presence and location of acute myocardial infarction.

Acute Disease↗

PubMed1976

Methods for measurement of cerebral blood flow in man.

A survey of the currently available methods for the measurement of cerebral blood flow in man is given. Many of the clinically important brain diseases such as tumors, stroke, brain trauma or epilepsy entail focal or regional flow alterations. Therefore a special emphasis is placed on methods allowing measurements of regional cerebral flow, rCBF. The intra-arterial 133Xenon injection method is now widely used as a standard method for rCBF measurement. It affords a good two-dimensional resolution when using a suitable dynamic gamma camera which allows a high counting rate to be recorded. But, due to the superposition of tissues the three-dimensional resolution is limited. This, in particular, means that smaller areas of ischemia (low flow) tend to be overlooked whereas local hyperemia is readily discerned. The 133Xenon inhalation method is less accurate, contaminated by extra-cerebral uptake, and insensitive both for detecting regional ischemia and regional hyperemia. The spatial resolution is also much more limited. For these reasons great caution must be exercised in interpreting the results. Methods yielding three-dimensional rCBF data will be needed in order to gain more precise information both on spatial localization and, especially, on ischemic areas. The most promising is computer-assisted axial tomography with freely diffusible radioactive isotopes or with x-rays using an intra-arterial injection of contrast. But, the available techniques are still too slow: in order to measure blood flow one "exposure" must be taken every second. Only a few methods give quantitative information of the blood flow in the human brain. This is mainly due to the inaccessibility of the brain within the skull and to the complexity of the cerebral arterial and venous systems. Before reviewing the various methods used in man, it should be mentioned, that much of the fundamental knowledge has been gained by methods only applicable to animals. Measurements of the diameter of the small arteries on the surface of the brain antedates even the classical studies of Roy and Sherrington (1890). This technique continues to be useful, modern technical improvements consisting of the use of micropipettes and a stereo microscope in combination with an image splitter and a television camera which allows the accurate assessment of diameter variations of a few percent [22]. Autoradiography of brain slices using diffusible indicators is the best quantitative method for measuring local blood flow in a great many parts of the brain [7, 45]. Microspheres are also being used, but it is still not quite clear that this technique gives reliable quantitative data in small masses of tissue [34, 41, 50].

Animals↗

PubMed2026

Analysis of deep learning techniques in computer-aided diagnosis for meniscus injuries: a systematic literature review.

Meniscus informatics is a growing subject of study in the healthcare industry. One of the major hindrances to the healthcare system's transformation is obtaining knowledge and meaningful information from complicated, high-dimensional and diverse sources. Modern biomedical research, for instance, has seen an increase in the use of complex, dissimilar, poorly documented, and generally unstructured electronic health records, imaging, sensor data and text, even after many current techniques have been used to extract more robust and useful elements from the data for analysis. New efficient standards for building end-to-end learning models from complex data are therefore needed. Therefore, the current study aims to examine the most recent research on the use of deep learning techniques for diagnosing meniscus tears and recommend creating comprehensive and meaningful interpretable structures that might benefit the healthcare industry. We also draw attention to shortcomings and the need for better technique development, and we provide new perspectives about this exciting new development in the field.

Humans↗

PubMedDate not supplied

X-ray solution scattering studies on vinblastine-induced polymers of microtubule protein: structural characterisation and effects of temperature.

We report here on X-ray solution scattering and electron microscopy studies of microtubule protein in the presence of the antimitotic drug, vinblastine. In buffer conditions used for microtubule assembly, vinblastine caused the formation of coil-like structures. The coils appeared to be made up of two protofilaments. Details of the structure and behaviour of coils in solution were obtained from interpretation of their solution scattering patterns. Upon increasing temperature from 4 to 37 degrees C the pitch of the coils increased from 25.92 to 26.96 nm. However, little change was observed in their mean diameters (38.46 and 38.45 nm, respectively). Increasing the temperature also favoured increased formation and/or elongation of the coils. The effect of temperature on the pitch was fully reversible. Vinblastine-induced assembly of pure tubulin also showed the formation of coils. However, these coils appeared to consist of only one protofilament. Their mean diameters (38.35 nm) were similar to those of the coils formed from microtubule protein.

Animals↗

PubMedDate not supplied

The Staphylococcus aureus alpha-toxin channel complex and the effect of Ca2+ ions on its interaction with lipid layers.

Using the techniques of two-dimensional crystallization on supported lipid bilayers together with computer image processing, two distinct two-dimensional crystal types of staphylococcal alpha-toxin complex are formed depending on the presence or absence of Ca2+ ions. Without Ca2+, these are hexagonally packed (in A, a = b = 89.5 +/- 2.5 A; theta = 119.7 degrees) With Ca2+ present, rectangular crystal packing is seen (in A, a = 114.8 +/- 1.6 A, b = 140.2 +/- 0.7 A; theta = 89.1 degrees). A third, banded crystal type is also seen which is interpreted as a side-to-side packing of regular tubules. We use these tubular crystals for cross-correlation searches with top and side-on views of the complex from single particle reconstructions, and with the repeating units from the two-dimensional crystal types. The results lead us to propose a model in which the different two-dimensional crystal types are formed as a result of alpha-toxin hexamers packing in different orientations. In the hexagonal crystals the hexamers lie end-on with a 6-fold axis in projection. On the addition of Ca2+, the hexamers reorient to lie tilted with respect to the support, thus giving rise to a rectangular projection.

Bacterial Toxins↗

PubMed1992

Polyaxonal amacrine cells of rabbit retina: PA2, PA3, and PA4 cells. Light and electron microscopic studies with a functional interpretation.

Polyaxonal (PA) amacrine cells are a new class of amacrine cell bearing one to six branching, axon-like processes that emerge from the cell body or dendritic trees within 50 microns of the cell body. These slender processes of uniform caliber branch at right angles and in many respects closely resemble the axons of Golgi type II cells found elsewhere in the brain. Of the four types of polyaxonal amacrine cell that we have recognized in rabbit retina, two have been described previously in brief communications. One of these, the PA1 amacrine cell with its interstitially displaced cell body, located in the inner plexiform layer (IPL), has been analyzed extensively in two preceding reports. This paper concerns PA2, PA3, and PA4 amacrine cells. Type 2 polyaxonal (PA2) amacrine cells, identified in Golgi preparations of whole-mounted rabbit retinas, have smaller cell bodies (9-14 microns) than the other three types and these are always displaced to the ganglion cell layer (GCL) or the inner border of the inner plexiform layer (IPL). The dendritic fields of PA2 cells are also smaller than those of other PA amacrine cells, and most of their sparse dendritic branching is narrowly stratified at the border of strata (S) 4 and 5. Some members of this more heterogeneous amacrine cell "type" are bistratified, however, and more highly branched with terminal branches rising to end in S1. PA2 amacrine cells bear a scattering of small dendritic spines and may also exhibit complex dendritic appendages arising at the ends of terminal branches in proximal regions of the dendritic tree. PA2 cells emit one to three axons from the proximal dendritic tree, and about half of the cells bear a single axon. Type 3 polyaxonal (PA3) amacrine cells resemble PA1 cells in the large size of their cells bodies (11-16 microns) and dendritic fields, but differ from the latter in placement of cell bodies, which is in the GCL, and dendritic and axonal stratification, which is multistratified, ranging from S4 to S1, with a concentration in S3 or S4 and a variable contribution to S1. PA3 cells differ from PA1 cells in several other respects, including dendritic branching which occurs at higher frequency and is biased toward temporal retina, and in characteristic bristling dendritic spines, clustered in the intermediate regions of the dendritic tree, that are longer, more variable in appearance and more tightly clustered than the small, uniform spines of PA1 cells that are clustered on proximal dendrites.(ABSTRACT TRUNCATED AT 400 WORDS)

Adaptation, Ocular↗

PubMed1992

Oral diagnostic reporting and synchronized image filing using magneto-optical disks.

An experimental radiologic reporting system has been developed and tested. The rewritable and compact magneto-optical disk (MOD) is applied to storing medical images with oral diagnostic reports of these radiologic images. The disk is 5.25 inches in diameter, has 600 MB memory capacity, is erasable, light and compact. Advantages are simultaneous recording of radiologic images and their oral reports by radiologists, and application to circulation of media inside the hospital as well as to filing of medical images. The MOD has a multimedia function of communication and filing. When medical images are taken and stored, oral interpretation by radiologists can be simultaneously added. Physicians can get information of the images and their reports by oral speech at the same time in front of computer workstation. Furthermore, integration of a voice recognition capability is now being undertaken.

Image Processing, Computer-Assisted↗

PubMed1977

New approach to interpretation of technetium-99m pyrophosphate scintigraphy in detection of acute myocardial infarction: clinical assessment of diagnostic accuracy.

A modified classification for interpreting technetium-99m pyrophosphate scintigrams defines the 2+ diffuse pattern of tracer uptake as equlvocal rather than positive for acute myocardial infarction. Results of scintigraphy using this classification were compared with results of standard diagnostic tests for myocardial infarction in 235 patients admitted to a coronary care unit with acute chest pain. Of 81 patients with acute transmural infarction by standard clinical, electrocardiographic and serum enzyme criteria, 76 had a positive, 5 an equivocal and none a negative scintigram. Of 18 with acute nontransmural infarction by standard criteria, 7 had a positive, 9 an equivocal and 2 a negative scintigram. This it was uncommon for a patient with acute myocardial infarction, transmural or nontransmural, to have a definitely negative technetium-99m pyrophosphate study. Ten patients had equivocal evidence of infarction by standard criteria. Of the remaining 126 patients with no evidence of acute myocardial infarction by standard criteria, 87 had a negative, 35 an equivocal and 4 a definitely positive scintigram. Thus the definitely positive scintigraphic pattern was relatively highly specific for acute myocardial infarction. If the 2+ pattern had been considered positive, the specificity of the technique would have been greatly decreased. Computer processing strengthened observer certainty of the visual impression but changed the scintigraphic evaluation in only eight cases. Thus, use of an equivocal pattern renders technetium-99m pyrophosphate imaging both an extremely sensitive and specific method for detecting acute myocardial infarction.

Acute Disease↗