Single Image Acquisition Research Articles

Experimental Measurement of Scatter to Primary Ratio by Localized Primary Modulation in Industrial Computed Radiography

The scatter-to-primary ratio (SPR), can serve as an important parameter for performing the scatter correction procedures or build up factor determination in radiography projections. In this work an experimental technique is presented based on localized primary modulation for direct SPR measurement. As illustrative examples, the SPR is measured for steel and aluminum step wedges to demonstrate the applicability of the presented technique in computed radiography. As a required parameter, the effective transmission factor of the modulator is measured using primary beam stopping concept over a calibration block. This technique has significant advantages such as a straight forward theory, simplified applicability in industrial site conditions, beam hardening consideration as well as automation possibility. The technique works by a single image acquisition, without image data loss in the interested area.

Electrochemical Imaging of Dense Molecular Nanoarrays.

The aim of the present work is to explore the combination of atomic force electrochemical microscopy, operated in molecule touching mode (Mt/AFM-SECM), and of dense nanodot arrays, for designing an electrochemically addressable molecular nanoarray platform. A high density nanoarray of single grained gold nanodots (∼15 nm-diameter nanoparticles, 100 nm pitch) is decorated by a model molecular system, consisting of ferrocene (Fc) labeled polyethylene glycol (PEG) disulfide chains. We show that the high resolution of Mt/AFM-SECM enables the electrochemical interrogation of several hundreds of individual nanodots in a single image acquisition. As a result, the statistical dispersion of the nanodot molecular occupancy by Fc-PEG chains can be reliably quantified, evidencing that as little as a few tens of copies of redox-labeled macromolecules immobilized on individual nanodots can be detected. The electrochemical reactivity of individual nanodots can also be reliably sampled over a large population of nanodots. We evidence that the heterogeneous rate constant characterizing the electron transfer between the nanodots and the Fc heads displays some quantifiable variability but that the electron transfer remains in any case in the quasi-reversible regime. Overall, we demonstrate that Mt/AFM-SECM enables high throughput reading of dense nanoarrays, with a sensitivity and a read-out speed considerably higher than previously reported for scanning electrochemical microscopy (SECM) imaging of molecular microarrays.

SPARSE (spatially phase-retarded spectroscopic ellipsometry) for real-time film analysis.

In this Letter, we propose a novel type of spectroscopic ellipsometer, named spatially phase-retarded spectroscopic ellipsometry (SPARSE), based on the spatial polarization distribution opposed to the temporal polarization changes. SPARSE can collect all information necessary to characterize film structures with a single image acquisition, and it has the benefit of real-time measurements. For the verification, feasible experiments with single film-layered certificated reference materials and multi-layered film specimens were carried out.

Fetal cardiac function: Feasibility in obtaining the right modified myocardial performance index in a single Doppler waveform.

We aimed to assess the feasibility of assessing the fetal right Myocardial Performance Index (RMPI) using single waveform and to compare absolute values with dual technique. We studied 145 morphologically normal appropriately grown fetuses at 16-28 weeks' gestation with local Ethics Committee approval using fixed machine settings: Doppler sweep velocity at 15 cm/s; angle of insonation <150; wall motion filter 300 Hz. Doppler gate was 3 mm, increased to 4-5 mm if needed. RMPI was obtained twice in the same fetus; using 'dual-image' and 'single-image' techniques. Dual images were acquired as previously described. Single images were taken from the tip or just below the tricuspid valve towards the ventricular septum in the apical four-chamber view. RMPI was calculated using two-value (a-b/b) or three-value (ICT+IRT/ET) formulae where 'a', 'b' or (ET) represent the isovolumetric and ejection times, and ICT and IRT represent the isovolumetric contraction and relaxation times. Dual image was accessible in 100% of fetuses. Single-image acquisition was 100%, 92.3% and 76.5% at 16+0-24+0, 24+1-27+0, and 27+1-28+0 weeks respectively (95.2% overall). Doppler gate increased in 23 cases (16.6%); 8/17 (47%) at 27+1-28+0 weeks' gestation. Mean and standard deviation for 'dual image' and 'single image' were: RMPI 0.46 ± 0.09 and 0.49 ± 0.07; 'a' 249.06 ± 11.50 and 249.11 ± 11.93; 'b' 170.85 ± 8.95 and 167.62 ± 8.39. Single-image acquisition RMPI is highly feasible from 16 to 26 weeks gestation. Difference in mean values may represent overestimation of ejection time in the 'dual-image' technique.

In Situ Hybridization and Double Immunohistochemistry for the Detection of VEGF-A mRNA and CD34/Collagen IV Proteins in Renal Transplant Biopsies.

Quantitative metrics on the tissue distribution of different cell phenotypes, extracellular matrix components, and signaling/cell cycle markers hold the promise for the advent of new-generation tissue-based predictive/prognostic biomarkers in clinical diagnostics. The workflow of this approach is composed of three major phases: (1) detection of multiple molecular targets on a single histologic section, (2) image acquisition, and (3) digital image processing and analysis. Here, we present the most prevalent current alternatives for step (1) and describe a three-plex staining and image acquisition platform that captures the spatial distribution of macromolecules from two different species.

Beam-induced atomic migration at Ag-containing nanofacets at an asymmetric Cu grain boundary

Abstract

Measuring body composition and regional fat mass accurately

Measuring body composition and regional fat mass accurately

Multimodal optical coherence tomography and fluorescence lifetime imaging with interleaved excitation sources for simultaneous endogenous and exogenous fluorescence.

Multimodal imaging probes a variety of tissue properties in a single image acquisition by merging complimentary imaging technologies. Exploiting synergies amongst the data, algorithms can be developed that lead to better tissue characterization than could be accomplished by the constituent imaging modalities taken alone. The combination of optical coherence tomography (OCT) with fluorescence lifetime imaging microscopy (FLIM) provides access to detailed tissue morphology and local biochemistry. The optical system described here merges 1310 nm swept-source OCT with time-domain FLIM having excitation at 355 and 532 nm. The pulses from 355 and 532 nm lasers have been interleaved to enable simultaneous acquisition of endogenous and exogenous fluorescence signals, respectively. The multimodal imaging system was validated using tissue phantoms. Nonspecific tagging with Alexa Flour 532 in a Watanbe rabbit aorta and active tagging of the LOX-1 receptor in human coronary artery, demonstrate the capacity of the system for simultaneous acquisition of OCT, endogenous FLIM, and exogenous FLIM in tissues.

A New Method for Determining the Composition of Core–Shell Nanoparticles via Dual‐EDX+EELS Spectrum Imaging

Simultaneously acquired microanalytical X‐ray and electron energy loss signals are obtained from a bimetallic core–shell nanoparticle system (FePt@Fe3O4). The signals are decomposed using independent component analysis and the extracted components are used to separately quantify the composition of the spatially overlapping core and shell phases in the nanoheterostructure. The utilization of the complementary strengths of energy dispersive X‐ray and electron energy‐loss spectroscopy microanalysis has enabled the quantification of both light and heavy elements in a single spectrum image acquisition.

SU‐G‐IeP1‐02: Automated SNR Analysis of MR Images Using Model‐Based Noise Determination

Purpose:To develop a robust automated method of signal‐to‐noise (SNR) analysis from MR images using a single image acquisition approach and model‐based noise determination.Methods:Three consecutive MRI phantom scans were performed according to the SNR test procedures in the 2015 ACR MRI Quality Control Manual. This was repeated for several different RF coils and on MRI scanners from two different vendors. The three images from each RF coil were analyzed by the single‐image (SNR‐ACR1) and two‐image (SNR‐ACR2) SNR analysis methods also described in the ACR QC Manual. In addition the images were analyzed by the automated method (SNR‐AUTO). The SNR‐AUTO method utilizes an ImageJ macro file that was developed to 1) segment the phantom from the background region by means of a simple histogram‐based thresholding algorithm, 2) measure the signal from a ROI encompassing 80% of the phantom area, and 3) determine noise by fitting the histogram of the background region (devoid of the phase encode direction) to a noise distribution model established in the literature.Results:The accuracy of the SNR‐AUTO analysis method is demonstrated by it yielding SNR results that on average were −0.8% ± 6.7% of the SNR‐ACR1 method and 7.5% ± 8.6% of the SNR‐ACR2 method. The SNR‐AUTO method demonstrated a higher level of reproducibility (average COV = 0.32%) than that of the other two methods (average COV = 1.01% and 1.69% for SNR‐ACR1 and SNRACR2 respectively) both of which require manual placement of ROIs. An additional finding is that the model‐based noise determination is relatively insensitive to the presence of minor artifacts in the background region.Conclusion:The SNR‐AUTO method proved to be an accurate, highly reproducible, time‐efficient method for analysis of SNR in MR images and is insensitive to minor artifacts in the noise‐measuring region.

Effective Photon Count Estimation from a Single Image Acquisition

Most image sensors do not directly report the actual number of detected photons per pixel, but instead a value generated after the photo-electrons registered on a physical sensor have passed through an electronic pipeline of amplifiers and charge offsets. Knowledge of the actual photon count is necessary to implement maximum likelihood estimates to extract model parameters from biological fluorescence images. In order to estimate the photon count of an image, the effective gain and offset of the image acquisition device must be measured. The standard gain calibration process for cameras is performed by recording tens of calibration and dark images and then performing a linear regression of the gain by plotting the variance over the acquisitions as a function of intensity. We propose a method to compute the gain from a single image acquisition without pre-calibration by utilizing information in the frequencies outside of the optical transfer function (OTF). Since noise is not limited by the cut off frequency of the OTF, estimation of the out of band energy relative to the total energy allows for the calculation of the gain. We show that this procedure is as precise as traditional gain estimation and is an essential step in automating super resolution software.

Multiview hyperspectral topography of tissue structural and functional characteristics.

Accurate and in vivo characterization of structural, functional, and molecular characteristics of biological tissue will facilitate quantitative diagnosis, therapeutic guidance, and outcome assessment in many clinical applications, such as wound healing, cancer surgery, and organ transplantation. We introduced and tested a multiview hyperspectral imaging technique for noninvasive topographic imaging of cutaneous wound oxygenation. The technique integrated a multiview module and a hyperspectral module in a single portable unit. Four plane mirrors were cohered to form a multiview reflective mirror set with a rectangular cross section. The mirror set was placed between a hyperspectral camera and the target biological tissue. For a single image acquisition task, a hyperspectral data cube with five views was obtained. The five-view hyperspectral image consisted of a main objective image and four reflective images. Three-dimensional (3-D) topography of the scene was achieved by correlating the matching pixels between the objective image and the reflective images. 3-D mapping of tissue oxygenation was achieved using a hyperspectral oxygenation algorithm. The multiview hyperspectral imaging technique was validated in a wound model, a tissue-simulating blood phantom, and in vivo biological tissue. The experimental results demonstrated the technical feasibility of using multiview hyperspectral imaging for 3-D topography of tissue functional properties.

Wide-field in vivo oral OCT imaging.

We have built a polarization-sensitive swept source Optical Coherence Tomography (OCT) instrument capable of wide-field in vivo imaging in the oral cavity. This instrument uses a hand-held side-looking fiber-optic rotary pullback catheter that can cover two dimensional tissue imaging fields approximately 2.5 mm wide by up to 90 mm length in a single image acquisition. The catheter spins at 100 Hz with pullback speeds up to 15 mm/s allowing imaging of areas up to 225 mm(2) field-of-view in seconds. A catheter sheath and two optional catheter sheath holders have been designed to allow imaging at all locations within the oral cavity. Image quality of 2-dimensional image slices through the data can be greatly enhanced by averaging over the orthogonal dimension to reduce speckle. Initial in vivo imaging results reveal a wide-field view of features such as epithelial thickness and continuity of the basement membrane that may be useful in clinic for chair-side management of oral lesions.

SU‐E‐J‐06: Additional Imaging Guidance Dose to Patient Organs Resulting From X‐Ray Tubes Used in CyberKnife Image Guidance System

Purpose:The use of image‐guided radiation therapy (IGRT) has become increasingly common, but the additional radiation exposure resulting from repeated image guidance procedures raises concerns. Although there are many studies reporting imaging dose from different image guidance devices, imaging dose for the CyberKnife Robotic Radiosurgery System is not available. This study provides estimated organ doses resulting from image guidance procedures on the CyberKnife system.Methods:Commercially available Monte Carlo software, PCXMC, was used to calculate average organ doses resulting from x‐ray tubes used in the CyberKnife system. There are seven imaging protocols with kVp ranging from 60 – 120 kV and 15 mAs for treatment sites in the Cranium, Head and Neck, Thorax, and Abdomen. The output of each image protocol was measured at treatment isocenter. For each site and protocol, Adult body sizes ranging from anorexic to extremely obese were simulated since organ dose depends on patient size. Doses for all organs within the imaging field‐of‐view of each site were calculated for a single image acquisition from both of the orthogonal x‐ray tubes.Results:Average organ doses were &lt;1.0 mGy for every treatment site and imaging protocol. For a given organ, dose increases as kV increases or body size decreases. Higher doses are typically reported for skeletal components, such as the skull, ribs, or clavicles, than for softtissue organs. Typical organ doses due to a single exposure are estimated as 0.23 mGy to the brain, 0.29 mGy to the heart, 0.08 mGy to the kidneys, etc., depending on the imaging protocol and site.Conclusion:The organ doses vary with treatment site, imaging protocol and patient size. Although the organ dose from a single image acquisition resulting from two orthogonal beams is generally insignificant, the sum of repeated image acquisitions (&gt;100) could reach 10–20 cGy for a typical treatment fraction.

Survey and analysis of various image fusion techniques for clinical CT and MRI images

ABSTRACTThe research and development of biomedical imaging techniques requires more number of image data from medical image acquisition devices, like computed tomography (CT), magnetic resonance imaging (MRI), positron emission technology, and single photon emission computed tomography. Multimodal image fusion is the process of combining information from various images to get the maximum amount of content captured by a single image acquisition device at different angles and different times or stages. This article analyses and compares the performance of different existing image fusion techniques for the clinical images in the medical field. The fusion techniques compared are simple or pixel‐based fusion, pyramid‐based fusion, and transform‐based fusion techniques. Four set of CT and MRI images are used for the above fusion techniques. The performance of the fused results is measured with seven parameters. The experimental results show that out of seven parameters the values of four parameters, such as average difference, mean difference, root mean square error, and standard deviation are minimum and the values of remaining three parameters, such as peak signal to noise ratio, entropy, and mutual information are maximum. From the experimental results, it is clear that out of 14 fusion techniques taken for survey, image fusion using dual tree complex wavelet transform gives better fusion result for the clinical CT and MRI images. Advantages and limitations of all the techniques are discussed with their experimental results and their relevance. © 2014 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 24, 193–202, 2014.

Postmortem computed tomography age assessment of juvenile dentition: comparison against traditional OPT assessment

Age estimation is one of the primary demographic features used in the identification of juvenile remains. Determining the accuracy and repeatability of age estimations based on postmortem computed tomography (PMCT) data compared with those using conventional orthopantomography (OPT) images is important to validate the use of PMCT as a single imaging technique in forensic and disaster victim identification (DVI). In this study, 19 juvenile mandibles and maxilla of known age underwent both OPT and PMCT. Three raters then estimated dental age using the resulting images and 3D reconstructions. This assessment showed excellent agreement between the age estimations using the two techniques for all three observers. PMCT also offers a greater range of measurements for both the dentition and the whole human skeleton using a single image acquisition and therefore has the potential to improve both the speed and accuracy of age estimation.

Proposal of a magnetic resonance technique for the evaluation of the calcaneofibular ligament minimizing false positive results.

BackgroundMagnetic resonance (MR) techniques used to detect lesions of the ligament complex for articulation of the ankle lack the desired accuracy for the study of the calcaneofibular ligament (CFL). The lack of sensitivity of the conventional techniques is due to variations in the dimensions of the CFL. The best results are obtained when the image plane is oriented parallel to the ligament. This study aims to develop a model that addresses the width, length and angle parameters of the CFL and the orientation of the MR image plane, and thus determine a technique in the oblique transversal plane with the foot in anatomical flexion, that is adequate for the majority of patients.MethodTo determine this orientation and adapt it to the majority of people, images of the articulation of the ankle in the 3D isotropic, volumetric, sagittal plane of 100 volunteers were taken using the MR technique. None of the volunteers had a clinical history of ligament lesions, serious pathologies, or surgeries. A measurement of the length, width, and angle of the CFL relative to the sole of the foot was performed using the MR tools. A virtual model was developed that simulated the visualization of the CFL in the oblique transversal image plane from 35° to 45° using the CFL dimensions of 100 volunteers. The comparison of the simulations with the reconstructed images validated the model and permitted the calculation of the agreement and sensitivity of each technique in the detection of the complete CFL.ResultsUsing the simulator, it was possible to obtain the limit angle for complete CFL visualization as a function of its dimensions for any angle of the oblique transversal image plane of the MR.ConclusionThe results suggest that a single image acquisition technique in the oblique transversal plane at 38° with the foot in anatomical flexion would serve the majority of patients.

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Collaborative patch-based super-resolution for diffusion-weighted images

In this paper, a new single image acquisition super-resolution method is proposed to increase image resolution of diffusion weighted (DW) images. Based on a nonlocal patch-based strategy, the proposed method uses a non-diffusion image (b0) to constrain the reconstruction of DW images. An extensive validation is presented with a gold standard built on averaging 10 high-resolution DW acquisitions. A comparison with classical interpolation methods such as trilinear and B-spline demonstrates the competitive results of our proposed approach in terms of improvements on image reconstruction, fractional anisotropy (FA) estimation, generalized FA and angular reconstruction for tensor and high angular resolution diffusion imaging (HARDI) models. Besides, first results of reconstructed ultra high resolution DW images are presented at 0.6×0.6×0.6mm3 and 0.4×0.4×0.4mm3 using our gold standard based on the average of 10 acquisitions, and on a single acquisition. Finally, fiber tracking results show the potential of the proposed super-resolution approach to accurately analyze white matter brain architecture.

Focus on bioinstrumentation and biotechnologies

Focus on bioinstrumentation and biotechnologies