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Results for “multiplex imaging”

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PubMed1998

Volumetric Holography of Cardiac Defects in Humans: Initial Clinical Experience Using Tomographic Echocardiographic Data.

We have previously described a method to develop holograms that does not entail the presence of laser light source in the clinical environment. Although we have demonstrated the feasibility of holography from cardiac ultrasound data to depict normal and abnormal cardiac anatomy in experimental studies, the ability of holography from ultrasound data to image structural cardiac anomalies in patients is not known. In this exploratory study, we addressed the question of whether it was possible to image cardiac pathology by holography in patients with mitral valve disease, atrial septal defects, and ventricular aneurysms. Parallel, tomographic echocardiographic data obtained during transesophageal echocardiography were used to generate holograms of cardiac disorders. Holographic three-dimensional (3-D) reproduction contains up to 1024 by 1024 pixels and full gray scale in each of the individual slices. Holograms of cardiac defects depicted their true spatial location, which not only enhanced the anatomic appreciation of the defect itself, but also revealed the depth and the relationship of the structures in proximity of the defect. Thus, 3-D imaging of cardiac anomalies by volumetric multiplexed holography is feasible.

Journal Article↗

PubMed2002

Coherent optical information systems.

Coherent optical beams are used to communicate, store, and process information in a growing number of applications. The availability of coherent laser sources is of critical importance for the realization of such optical information systems. An incoherent source randomly populates the available temporal and spatial channels of the optical system, making it difficult to represent information. Coherent laser sources provide a stable carrier on which to encode information, making it possible to realize powerful information-processing techniques such as wavelength division multiplexing in fiber networks, gated holographic imaging, and three-dimensional optical data storage.

Journal Article↗

PubMed2026

Impact of spatial distribution of M2 macrophages on prognosis and neoadjuvant chemotherapy resistance in gastric cancer.

BACKGROUND: Neoadjuvant chemotherapy (NAC) is a crucial treatment for locally advanced gastric cancer; however, approximately 30-40% of patients experience primary resistance, the mechanisms of which urgently require elucidation. The tumor microenvironment exhibits a high degree of spatial heterogeneity. M2 macrophages, as critical immune cells within this environment, are typically associated with poor prognosis. Yet, whether their spatial distribution impacts chemotherapy efficacy remains unclear. This study aims to investigate the relationship between the in situ spatial distribution characteristics of M2 macrophages and chemoresistance in gastric cancer. METHODS: Based on The Cancer Genome Atlas Stomach Adenocarcinoma (TCGA-STAD) cohort, the association between M2 markers (CD163, MRC1) and histological grade as well as overall survival (OS) was evaluated. Spearman correlation and functional enrichment analyses were conducted to explore the mechanistic link between M2 macrophages and stromal barrier construction. Multiplex immunofluorescence (mIF) and digital pathology image analysis were utilized to calculate the areal density of M2 macrophages in the intratumoral core and the peritumoral stroma, respectively. The tumor-to-peritumoral ratio (TPR) was constructed, followed by a rank correlation analysis between TPR and the tumor regression grade (TRG). RESULTS: TCGA-STAD results confirmed that patients with high expression of M2 markers had worse OS (P=0.03), and the expression levels of M2 markers increased with histological grade. MRC1 was highly significantly and positively correlated with the pro-fibrotic factor TGFB1 (rho=0.447, P<0.001), with the gene set significantly enriched in pathways such as positive regulation of cytokine production and myeloid leukocyte activation. Histological examination revealed that in chemoresistant patients (TRG 3), M2 macrophages were primarily retained in the peritumoral stroma, with a median TPR of 0.50; in chemosensitive patients (TRG 1-2), a massive influx of M2 macrophages into the tumor core was observed, with a median TPR of 6.67. TPR was negatively correlated with TRG (rs=-0.65, P=0.043). CONCLUSIONS: The clinical impact of M2 macrophages in the gastric cancer microenvironment is highly dependent on their spatial distribution. The peritumoral-enriched pattern (TPR <1) mediates primary chemoresistance, whereas high infiltration in the core objectively reflects the pathological footprint following effective chemotherapy. The TPR serves as a novel tool for assessing neoadjuvant chemosensitivity in gastric cancer.

Gastric cancer (GC)↗

PubMed2006

Automated quantification of quantum-dot-labelled epidermal growth factor receptor internalization via multiscale image segmentation.

The ability to monitor epidermal growth factor receptor (EGFr) internalization specifically, and cellular protein concentrations and activation states in general, has been recently improved by the use of appropriately functionalized quantum dots (QDs), as a result of the long-lasting fluorescence, brightness and multicolour of these nanoparticles. However, important quantitative information about locational proteomics is based on the analysis of the properties of many cells and cell cultures on a per-cell basis, rather than tracking individual events within one cell. Moreover, relative positional information is often gained from traditional staining protocols of distinct cellular compartments that are prone to noise, fading and low contrast. We apply a novel multiscale image segmentation based on region growing to classify automatically objects in fixed cell preparations and to define regional zones in all cells prior to QD concentration measures. This allows rapid quantitative description of EGFr internalization as it changes with incubation time. The capabilities realizable by simultaneous application of confocal imaging and functionalized QDs in conjunction with advanced image analysis are a prerequisite for automated and multiplexed cytomics assays.

Biotin↗

PubMed2002

Intrinsic fiber-optic ultrasonic sensor array using multiplexed two-wave mixing interferometry.

An intrinsic multiplexed laser interferometer is presented that allows for the simultaneous detection of acoustic waves by an array of fiber-optic sensors. The phase-modulated signals from each sensor are demodulated by use of an adaptive two-wave mixing setup. The light from each sensing fiber in the array is mixed with a reference beam in a single photorefractive crystal (PRC), and the output beams from the PRC are imaged onto separate photodetectors to create a multiplexed two-wave mixing (MTWM) system. The sensing fibers are embedded in graphite-epoxy composite panels, and detection of both acoustic emission and ultrasonic signals in these materials is demonstrated. The intrinsic MTWM system is an effective tool for the simultaneous demodulation of signals from a large fiber sensor array. Also, the adaptive nature of the MTWM setup obviates the need for active stabilization against ambient noise.

Journal Article↗

PubMedDate not supplied

DNA sequencing. Recent innovations and future trends.

Determination of the sequence of DNA is one of the most important aspects of modern molecular biology. New sequencing methods currently being developed enable DNA sequence to be determined increasingly faster and more efficiently. One of the major advances in sequencing technology is the development of automated DNA sequencers. These utilize fluorescent rather than radioactive labels. A laser beam excites the fluorescent dyes, the emitted fluorescence is collected by detectors, and the information analyzed by computer. Robotic work stations are being developed to perform template preparation and purification, and the sequencing reactions themselves. Research is currently in progress to develop the technology of mass spectrometry for DNA sequencing. Success in this endeavor would mean that the gel electrophoresis step in DNA sequencing could be eliminated. A major innovation has been the application of polymerase chain reaction (PCR) technology to DNA sequence determination, which has led to the development of linear amplification sequencing (cycle sequencing). This very powerful yet technically simple method of sequencing has many advantages over conventional techniques, and may be used in manual or automated methods. Other recent innovations proposed recently to increase speed and efficiency include multiplex sequencing. This consists of pooling a number of samples and processing them as pools. After electrophoresis, the DNA is transferred to a membrane, and sequence images of the individual samples are obtained by sequential hybridizations with specific labeled oligonucleotides. Multiplex DNA sequencing has been used in conjunction with direct blotting electrophoresis to facilitate transfer of the DNA to a membrane. Chemiluminescent detection can also be used in conjunction with multiplex DNA sequencing to visualize the image on the membrane.

Animals↗

PubMed2006

Real-time photodisplacement microscope for high-sensitivity simultaneous surface and subsurface inspection.

We have developed a new photodisplacement microscope system for practical use that achieves high-sensitivity simultaneous real-time imaging of surface and subsurface structures from a single space-frequency multiplexed interferogram. In this system a linear region of photothermal displacement is excited on the sample surface for subsurface imaging by a line-focused intensity-modulated laser beam. Surface information such as reflectivity and topography along with the displacement is detected with a charge-coupled device sensor-based parallel heterodyne interferometer. Surface and subsurface information components are space-frequency multiplexed into the sensor signal as orthogonal functions based on a frequency-optimized undersampling scheme, allowing each to be discretely reproduced by using a real-time Fourier analysis technique. Preliminary experiments demonstrate that this system is effective, simultaneously imaging reflectivity, topography, and photodisplacement for the detection of subsurface lattice defects in silicon, at a remarkable speed of only 0.26 s/256x256 pixel area. This new microscope is promising for nondestructive hybrid surface and subsurface inspection and other applications.

Journal Article↗

PubMed2002

Self-imaging properties of polychromatic Gaussian beams: application to wavelength demultiplexing and space routing.

We propose an analytical model of the self-imaging of Gaussian beams and discuss the impact of the finite aperture and the beam truncation on the quality of the self-image reconstruction. Extension to polychromatic operation is then presented in the context of wavelength division multiplexing systems. From the first point we derive conditions for good self-imaging, compatible with the requirements of the telecommunication environment. A basic optical setup is then proposed to implement both wavelength demultiplexing and routing in a lensless configuration.

Journal Article↗

PubMed2000

Active MR guidance of interventional devices with target-navigation.

This project incorporated a novel inductive coupling structure of three micro coils into an invasive device tip to determine both its tip position and orientation. Moreover, with the introduction of a new target-navigation technique the MR scan plane was defined automatically by the invasive device orientation and target tissue location. A time domain multiplexing technique was applied for simultaneous MR imaging and device tracking. Using these techniques, the acquired MR images always showed both the invasive device and its target tissue. Thus, roadmap images and their potential misregistration errors were avoided. A graphical user interface (GUI) was also designed to assist interventional physicians in monitoring and guiding the insertion of the interventional device. Ex vivo phantom and in vivo animal experiments were performed to test this new technique. The methods developed in this project provide a new active technique for interventional device guidance using MRI. Magn Reson Med 44:56-65, 2000.

Animals↗

PubMed2000

Arrayed primer extension: solid-phase four-color DNA resequencing and mutation detection technology.

The technology and application of arrayed primer extension (APEX) is presented. We describe an integrated system with DNA chip and template preparation, multiplex primer extension on the array, fluorescence imaging, and data analysis. The method is based upon an array of oligonucleotides, immobilized via the 5' end on a glass surface. A patient DNA is amplified by PCR, digested enzymatically, and annealed to the immobilized primers, which promote sites for template-dependent DNA polymerase extension reactions using four unique fluorescently labeled dideoxy nucleotides. A mutation is detected by a change in the color code of the primer sites. The technology was applied to the analysis of 10 common beta-thalassemia mutations. Nine patient DNA samples, each of which carries a different mutation, and four wild-type DNA samples were correctly identified. The signal-to-noise ratio of this technology is, on the average, 40:1, which enables the identification of heterozygous mutations with a high confidence level. The APEX method can be applied to any DNA target for efficient analysis of mutations and polymorphisms.

DNA↗

PubMed1977

Holographic displays for computer assisted tomography.

Generalized holographic methods may be used to provide three-dimensional displays from a series of adjacent tomograms. Two such methods are described. In the first method, the tomograms are simultaneously recorded as a single "space-multiplex" hologram, which thus reproduces the N images in proper relation to each other in space. In the second method, a single hologram of the total volume is theoretically synthesized.

Holography↗

PubMed2000

Time multiplexing and parallelization in multifocal multiphoton microscopy

We investigate the imaging properties of high-aperture multifocal multiphoton microscopy on the basis of diffraction theory. Particular emphasis is placed on the relationship between the sectioning property and the distance between individual foci. Our results establish a relationship between the degree of parallelization and the axial resolution for both two- and three-photon excitation. In addition, we show quantitatively that if a matrix of temporal delays is inserted between the individual foci, it is, for the first time to our knowledge, possible to solve the classical conflict between the light budget and the sectioning property in three-dimensional microscopy and to provide a virtually unlimited density of foci at best axial resolution.

Journal Article↗

PubMed2006

[Application of vertebroplasty, neuronavigation and kyphoplasty in the treatment of multiplex osteoporotic vertebral fractures--case report].

Vertebroplasty is a image-guided therapeutic procedure, consisting of an injection of acrylic cement through a bone biopsy needle into a vertebral body. Main indication for vertebroplasty is painful vertebral body compression fracture due to osteoporosis. The procedure is an efficient mean with high success in pain release and prevention of further collapse of the treated vertebrae; however, the technique does not allow to realign the spine. Kyphoplasty was designed to address the kyphotic deformity. It involves the percutaneous placement of an inflatable bone tamp into a vertebral body (VB). Restoration of VB height and kyphosis correction is achieved by inflation of the tamp with contrast material liquid. After deflation a cavity is created that eases the cement application. The most modern way of guidance in spinal surgery is neuronavigation--the use of frameless stereotaxy. The system reformats patient-specific CT images acquired prior surgery, performs image fusion with intraoperative plain X-ray. Before the operation, the surgeon may create surgical plan and simulate advancement of a virtual instrument along one or more surgical trajectories. During surgery, the system tracks the position of specialized surgical instruments. All three modalities mentioned above have been applied in the treatment of our patient suffered from multiple osteoporotic vertebral body compression fractures. Using kyphoplasty an almost total VB height restoration could be achieved. The pain relief was more than 50% after both operation.

Aged↗

PubMed2002

True colour imaging of the fundus using a scanning laser ophthalmoscope.

Currently retinal imaging is performed with the fundus camera. This has a number of limitations, in particular the high level of illuminations required for imaging. The scanning laser ophthalmoscope (SLO) has been proposed as an alternative imaging device but to date one of its main limitations has been that it gives only monochromatic images. In this paper we describe an SLO which uses low power red, green and blue lasers to image the human fundus. Using three lasers simultaneously to produce a colour image will increase the fundus exposure by a factor of three. To overcome this problem, a technique has been developed for multiplexing the lasers so that each point on the retina is imaged by the three lasers pulsed rapidly in sequence. The total exposure is thus kept to the same level as for a single laser and total imaging time is not increased. An example is shown of the image from a patient with diabetic retinopathy.

Calibration↗

PubMed1992

An experimental system for auditory image representations.

This paper presents an experimental system for the conversion of images into sound patterns. The system was designed to provide auditory image representations within some of the known limitations of the human hearing system, possibly as a step towards the development of a vision substitution device for the blind. The application of an invertible (1-to-1) image-to-sound mapping ensures the preservation of visual information. The system implementation involves a pipelined special purpose computer connected to a standard television camera. The time-multiplexed sound representations, resulting from a real-time image-to-sound conversion, represent images up to a resolution of 64 x 64 pixels with 16 gray-tones per pixel. A novel design and the use of standard components have made for a low-cost portable prototype conversion system having a power dissipation suitable for battery operation. Computerized sampling of the system output and subsequent calculation of the approximate inverse (sound-to-image) mapping provided the first convincing experimental evidence for the preservation of visual information in the sound representations of complicated images. However, the actual resolution obtainable with human perception of these sound representations remains to be evaluated.

Acoustics↗

PubMed2002

Comparison of the axial resolution of practical Nipkow-disk confocal fluorescence microscopy with that of multifocal multiphoton microscopy: theory and experiment.

We compare the axial sectioning capability of multifocal confocal and multifocal multiphoton microscopy in theory and in experiment, with particular emphasis on the background arising from the cross-talk between adjacent imaging channels. We demonstrate that a time-multiplexed non-linear excitation microscope exhibits significantly less background and therefore a superior axial resolution as compared to a multifocal single-photon confocal system. The background becomes irrelevant for thin (< 15 microm) and sparse fluorescent samples, in which case the confocal parallelized system exhibits similar or slightly better sectioning behaviour due to its shorter excitation wavelength. Theoretical and experimental axial responses of practically implemented microscopes are given.

Fluorescence Polarization↗

PubMed2004

Imaging using air-coupled polymer-membrane capacitive ultrasonic arrays.

Polymer-membrane capacitive ultrasonic linear and 2-D arrays have been fabricated for use in air-coupled imaging. By using arrays as receivers, there is a possibility of much faster imaging as the need for physically moving the receiver to scan a sample can be replaced by electronic multiplexing. In order to utilise this, a through-thickness air-coupled image of a composite plate has been made using a 2-D array as a receiver and a comparatively large planar source in air. This was made possible by the use of a chirp drive signal and cross-correlation on the measured waveform. Larger 2-D arrays with an increased number of elements have been simulated using a small scanned single receiver, and excellent imaging potential demonstrated. In addition two array receivers have been used in conjunction with two methods of post-processing, SAFT and ellipse crossing, to locate objects accurately.

Journal Article↗

PubMed2000

On-line coupling of high performance gel filtration chromatography with imaged capillary isoelectric focusing using a membrane interface.

A high performance liquid chromatography system, a sample preparation device, and an imaged capillary IEF (CIEF) instrument are integrated and multiplexed on-line. The system is equivalent to two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), by transferring the principle of 2-D separation to the capillary format. High performance liquid chromatography (HPLC) provides protein separation based on size using a gel filtration chromatography (GFC) column. Each eluted protein is sampled and directed to a novel microdialysis hollow fiber membrane device, where simultaneous desalting and carrier ampholyte mixing occurs. The sample is then driven to the separation column in an on-line fashion, where CIEF takes place. The fluidic technology used by our 2-D system leads to natural automation. The coupling of the two techniques is simple. This is attributed to high speed and efficiency of the sample preparation device that acts as an interface between the two systems, as well as the speed and simplicity of our whole column absorption imaged CIEF instrument. To demonstrate the feasibility of this approach, the separation of a mixture of two model proteins is studied. Sample preparation and CIEF were complete in just 4-5 min, for each of the eluted proteins. Total analysis time is about 24 min. Three-dimensional data representations are constructed. Challenges and methods to further improve our instrument are discussed, and the design of an improved horseshoe-shaped sample preparation sample loop membrane interface is presented and characterized.

Animals↗