Commercial Scanner Research Articles

Assessment of intraoral scanning technology for multiple implant impressions - A systematic review and meta-analysis.

Background:Intraoral scanner (IOS) is a medical device used for capturing direct optical impressions and composed of a handheld camera (hardware), a computer and software. Digital impressions by intraoral scanning have become an increasingly popular alternative to conventional impressions. The aim of this systematic review is to assess the studies regarding the various available technologies for IOS and evaluate the most accurate IOS system for cases with multiple implants and identify the factors that can influence its accuracy.Materials and Methods:A comprehensive electronic search was done in online databases, 'Pubmed', 'Google Scholar' and 'Cochrane' based on pre-determined eligibility criteria. In-vitro studies, In-vivo studies and Randomized controlled trials assessing the accuracy of intra-oral scanner technology were selected after thorough screening. The search strategy covered all studies published until February 2019 and yielded a total of 11 articles out of which 8 studies were determined to fulfil the inclusion criteria and were selected for this review. Data extraction from the included studies was conducted by the primary author and reviewed by the second author.Results:The information collected included sample size and population, study design, intervention, scanning methods, comparisons and outcome measures. 5 out of 8 included studies compared the distance deviation of the acquired scans from the true values while the remaining 3 studies gave trueness and precision values as the outcome variables. A forest plot on scanner precision displayed slightly higher precision levels in the TRIOS scanner compared to the other intraoral scanners.Conclusion:Despite the limitations this study, it can be concluded that active wavefront sampling is more accurate than the other intraoral scanning technology employed by commercial scanners.

Deep Efficient End-to-end Reconstruction (DEER) Network for Few-view Breast CT Image Reconstruction.

Breast CT provides image volumes with isotropic resolution in high contrast, enabling detection of small calcification (down to a few hundred microns in size) and subtle density differences. Since breast is sensitive to x-ray radiation, dose reduction of breast CT is an important topic, and for this purpose, few-view scanning is a main approach. In this article, we propose a Deep Efficient End-to-end Reconstruction (DEER) network for few-view breast CT image reconstruction. The major merits of our network include high dose efficiency, excellent image quality, and low model complexity. By the design, the proposed network can learn the reconstruction process with as few as parameters, where N is the side length of an image to be reconstructed, which represents orders of magnitude improvements relative to the state-of-the-art deep-learning-based reconstruction methods that map raw data to tomographic images directly. Also, validated on a cone-beam breast CT dataset prepared by Koning Corporation on a commercial scanner, our method demonstrates a competitive performance over the state-of-the-art reconstruction networks in terms of image quality. The source code of this paper is available at: https://github.com/HuidongXie/DEER.

A smoothed raster scanning trajectory based on acceleration-continuous B-spline transition for high-speed Atomic Force Microscopy

The scanning speed of atomic force microscopes (AFMs) is typically limited by the frequency of the triangular trajectory used in generating the raster scan. This is because the higher harmonics of the triangular trajectory have a tendency to excite the mechanical resonances of the nanopositioners incorporated in the AFM; thereby, introducing significant positioning errors. To address this issue, this article proposes a novel scanning trajectory smoothing method to enable high-speed raster scanning. The proposed method utilizes the acceleration-continuous B-spline to replace the backward path of the triangular trajectory for the fast axis. As a result, the advantage of uniform sampling along the forward path is preserved. The trajectory generation process is described in detail. A hysteresis compensation method is employed to improve the tracking performance of the scanner. Experiments conducted on a commercial piezoelectric tube scanner are presented to demonstrate the performance improvement delivered by the proposed method when compared with the traditional raster scanning method. It is shown that the proposed method enables a five-fold improvement in achievable scanning rate, from 10 to 50 Hz.

SCNIFFER: Low-Cost, Automated, Efficient Electromagnetic Side-Channel Sniffing

Electromagnetic (EM) side-channel analysis (SCA) is a prominent tool to break mathematically-secure cryptographic engines, especially on resource-constrained devices. Presently, to perform EM SCA on an embedded device, the entire chip is manually scanned and the MTD (Minimum Traces to Disclosure) analysis is performed at each point on the chip to reveal the secret key of the encryption algorithm. However, an automated end-to-end framework for EM leakage localization, trace acquisition, and attack has been missing. This work proposes SCNIFFER : a low-cost, automated EM Side Channel leakage SNIFFing platform to perform efficient end-to-end Side-Channel attacks. Using a leakage measure such as Test Vector Leakage Assessment (TVLA), or the signal to noise ratio (SNR), we propose a greedy gradient-search heuristic that converges to one of the points of highest EM leakage on the chip (dimension: $N \times N$ ) within $O(N)$ iterations, and then perform Correlational EM Analysis (CEMA) at that point. This reduces the CEMA attack time by $\sim N$ times compared to an exhaustive MTD analysis, and by $> 20\times $ compared to choosing an attack location at random. We demonstrate SCNIFFER using a low-cost custom-built 3-D scanner with an H-field probe ( $50, 000 commercial EM scanners, and a variety of microcontrollers as the devices under attack. The SCNIFFER framework is evaluated for several cryptographic algorithms (AES-128, DES, RSA) running on both an 8-bit Atmega microcontroller and a 32-bit ARM microcontroller to find a point of high leakage and then perform a CEMA at that point.

Echogenic Exosomes as ultrasound contrast agents.

Exosomes are naturally secreted extracellular bilayer vesicles (diameter 40–130 nm), which have recently been found to play a critical role in cell-to-cell communication and biomolecule delivery. Their unique characteristics—stability, permeability, biocompatibility and low immunogenicity—have made them a prime candidate for use in delivering cancer therapeutics and other natural products. Here we present the first ever report of echogenic exosomes, which combine the benefits of the acoustic responsiveness of traditional microbubbles with the non-immunogenic and small-size morphology of exosomes. Microbubbles, although effective as ultrasound contrast agents, are restricted to intravascular usage due to their large size. In the current study, we have rendered bovine milk-derived exosomes echogenic by freeze drying them in the presence of mannitol. Ultrasound imaging and direct measurement of linear and nonlinear scattered responses were used to investigate the echogenicity and stability of the prepared exosomes. A commercial scanner registered enhancement (28.9% at 40 MHz) in the brightness of ultrasound images in presence of echogenic exosomes at 5 mg mL−1. The exosomes also showed significant linear and nonlinear scattered responses—11 dB enhancement in fundamental, 8.5 dB in subharmonic and 3.5 dB in second harmonic all at 40 μg mL−1 concentration. Echogenic exosomes injected into the tail vein of mice and the synovial fluid of rats resulted in significantly higher brightness—as much as 300%—of the ultrasound images, showing their promise in a variety of in vivo applications. The echogenic exosomes, with their large-scale extractability from bovine milk, lack of toxicity and minimal immunogenic response, successfully served as ultrasound contrast agents in this study and offer an exciting possibility to act as an effective ultrasound responsive drug delivery system.

Catalogs of celestial bodies from digitized photographic plates of the Ukrainian Virtual Observatory Archive

The Ukrainian Virtual Observatory (UkrVO, http://ukr-vo.org) database is compiled from observations conducted in 1898-2018 at observational sites of 8 Ukrainian observatories with about 50 instruments. Now the UkrVO archive covers data of about 40,000 astroplates, from which 15,000 are digitized at three observatories: Main Astronomical Observatory of the NAS of Ukraine (MAO NASU), Research Institute 'Mykolaiv Astronomical Observatory' (RI MAO), and Astronomical Observatory of the Taras Shevchenko National University of Kyiv (AO TSNU). Astroplates were digitized using EpsonTM and MicrotekTM commercial scanners with 16-bit gray levels and resolution of 1200-1600 dpi. Images of all objects registered on plates were processed using the advanced software complex for CCD images' treatment MIDAS/ROMAFOT in the LINUX environment. Additional software modules developed and implemented at the MAO NASU and RI MAO provide both the digitized images' processing and the final products as the catalogs of positions and stellar magnitudes of all the registered objects. The processing of the digitized Northern Sky Survey observations (the FON project) resulted in a few catalogs of coordinates and B-magnitudes for more than 19 million stars and galaxies from the FON-Kyiv part and more than 13 million objects from the FON-Kitab part. Besides, based on these data, two catalogs for more than 5,000 positions and B-magnitudes of asteroids were compiled. Now, in cooperation with Hissar Astronomical Observatory (Dushanbe, Tajikistan), we are preparing similar catalogs based on digitized observations of the third part (1985-1992) of the FON project. The digitized data of open star clusters in UBVR color bands obtained at the Baldone observatory (Latvia) were used to enhance the photometric content of the resulted catalogs. The developed methods of digitization, image processing, and reduction with the latest reference catalogs allowed us to achieve good positional and photometric accuracy of objects. Other digitized data of photographic observations stored in UkrVO archives formed the basis of several Solar System Bodies positional catalogs. The compiled catalogs of 90 positions and B-values of Pluto, 1500 positions of satellites of outer planets are available on the UkrVO website and in the Strasbourg Data Center.

Dose Reduction for Sinus and Temporal Bone Imaging Using Photon-Counting Detector CT With an Additional Tin Filter.

The aim of this study was to quantitatively demonstrate radiation dose reduction for sinus and temporal bone examinations using high-resolution photon-counting detector (PCD) computed tomography (CT) with an additional tin (Sn) filter. A multienergy CT phantom, an anthropomorphic head phantom, and a cadaver head were scanned on a research PCD-CT scanner using ultra-high-resolution mode at 100-kV tube potential with an additional tin filter (Sn-100 kV) and volume CT dose index of 10 mGy. They were also scanned on a commercial CT scanner with an energy-integrating detector (EID) following standard clinical protocols. Thirty patients referred to clinically indicated sinus examinations, and two patients referred to temporal bone examinations were scanned on the PCD-CT system after their clinical scans on an EID-CT. For the sinus cohort, PCD-CT scans were performed using Sn-100 kV at 4 dose levels at 10 mGy (n = 9), 8 mGy (n = 7), 7 mGy (n = 7), and 6 mGy (n = 7), and the clinical EID-CT was performed at 120 kV and 13.7 mGy (mean CT volume dose index). For the temporal bone scans, PCD-CT was performed using Sn-100 kV (10.1 mGy), and EID-CT was performed at 120 kV and routine clinical dose (52.6 and 66 mGy). For both PCD-CT and EID-CT, sinus images were reconstructed using H70 kernel at 0.75-mm slice thickness, and temporal bone images were reconstructed using a U70 kernel at 0.6-mm slice thickness. In addition, iterative reconstruction with a dedicated sharp kernel (V80) was used to obtain high-resolution PCD-CT images from a sinus patient scan to demonstrate improved anatomic delineation. Improvements in spatial resolution from the dedicated sharp kernel was quantified using modulation transfer function measured with a wire phantom. A neuroradiologist assessed the H70 sinus images for visualization of critical anatomical structures in low-dose PCD-CT images and routine-dose EID-CT images using a 5-point Likert scale (structural detection obscured and poor diagnostic confidence, score = 1; improved anatomic delineation and diagnostic confidence, score = 5). Image contrast and noise were measured in representative regions of interest and compared between PCD-CT and EID-CT, and the noise difference between the 2 acquisitions was used to estimate the dose reduction in the sinus and temporal bone patient cohorts. The multienergy phantom experiment showed a noise reduction of 26% in the Sn-100 kV PCD-CT image, corresponding to a total dose reduction of 56% compared with EID-CT (clinical dose) without compromising image contrast. The PCD-CT images from the head phantom and the cadaver scans demonstrated a dose reduction of 67% and 83%, for sinus and temporal bone examinations, respectively, compared with EID-CT. In the sinus cohort, PCD-CT demonstrated a mean dose reduction of 67%. The 10- and 8-mGy sinus patient images from PCD-CT were significantly superior to clinical EID-CT for visualization of critical sinus structures (median score = 5 ± 0.82 and P = 0.01 for lesser palatine foramina, median score = 4 ± 0.68 and P = 0.039 for nasomaxillary sutures, and median score = 4 ± 0.96 and P = 0.01 for anterior ethmoid artery canal). The 6- and 7-mGy sinus patient images did not show any significant difference between PCD-CT and EID-CT. In addition, V80 (sharp kernel, 10% modulation transfer function = 18.6 cm) PCD-CT images from a sinus patient scan increased the conspicuity of nasomaxillary sutures compared with the clinical EID-CT images. The temporal bone patient images demonstrated a dose reduction of up to 85% compared with clinical EID-CT images, whereas visualization of inner ear structures such as the incudomalleolar joint were similar between EID-CT and PCD-CT. Phantom and cadaver studies demonstrated dose reduction using Sn-100 kV PCD-CT compared with current clinical EID-CT while maintaining the desired image contrast. Dose reduction was further validated in sinus and temporal bone patient studies. The ultra-high resolution capability from PCD-CT allowed improved anatomical delineation for sinus imaging compared with current clinical standard.

Super-resolution localization photoacoustic microscopy using intrinsic red blood cells as contrast absorbers

Photoacoustic microscopy (PAM) has become a premier microscopy tool that can provide the anatomical, functional, and molecular information of animals and humans in vivo. However, conventional PAM systems suffer from limited temporal and/or spatial resolution. Here, we present a fast PAM system and an agent-free localization method based on a stable and commercial galvanometer scanner with a custom-made scanning mirror (L-PAM-GS). This novel hardware implementation enhances the temporal resolution significantly while maintaining a high signal-to-noise ratio (SNR). These improvements allow us to photoacoustically and noninvasively observe the microvasculatures of small animals and humans in vivo. Furthermore, the functional hemodynamics, namely, the blood flow rate in the microvasculature, is successfully monitored and quantified in vivo. More importantly, thanks to the high SNR and fast B-mode rate (500 Hz), by localizing photoacoustic signals from captured red blood cells without any contrast agent, unresolved microvessels are clearly distinguished, and the spatial resolution is improved by a factor of 2.5 in vivo. L-PAM-GS has great potential in various fields, such as neurology, oncology, and pathology.

Comparing image quality in phase contrast sub[formula omitted] X-ray tomography—A round-robin study

How to evaluate and compare image quality from different sub-micrometer (subμ) CT scans? A simple test phantom made of polymer microbeads is used for recording projection images as well as 13 CT scans in a number of commercial and non-commercial scanners. From the resulting CT images, signal and noise power spectra are modelled for estimating volume signal-to-noise ratios (3D SNR spectra). Using the same CT images, a time- and shape-independent transfer function (MTF) is computed for each scan, including phase contrast effects and image blur (MTFblur). The SNR spectra and MTF of the CT scans are compared to 2D SNR spectra of the projection images. In contrary to 2D SNR, volume SNR can be normalized with respect to the object’s power spectrum, yielding detection effectiveness (DE) a new measure which reveals how technical differences as well as operator-choices strongly influence scan quality for a given measurement time. Using DE, both source-based and detector-based subμ CT scanners can be studied and their scan quality can be compared. Future application of this work requires a particular scan acquisition scheme which will allow for measuring 3D signal-to-noise ratios, making the model fit for 3D noise power spectra obsolete.

Smartphone Application as a Low-Cost Alternative for Digitizing Facial Defects: Is It Accurate Enough for Clinical Application?

To evaluate the accuracy of a smartphone application as a low-cost approach for digitizing a facial defect for 3D modeling. A stone model of a facial defect was scanned using industrial computed tomography (reference scan) and was also scanned five times using a commercial laser scanner. A series of 24 sequenced digital photographs was taken five times by smartphone at two elevations. These images were uploaded and processed by a cloud-based server to create virtual 3D models. The 3D datasets were geometrically evaluated and compared to the reference data using 3D evaluation software. Mann-Whitney U test was used for statistical analysis, and the significance was set at P < .05. The overall mean 3D deviation ± standard deviation for the smartphone dataset was 604.9 ± 123.5 μm compared to 67.5 ± 0.49 μm for the laser scanner. There was a significant difference in the accuracy between the commercial laser scanner and the smartphone application (P = .009). The results showed that within the limits of this study and in reference to standard computed tomography imaging, data acquisition with a smartphone for 3D modeling is not as accurate as commercially available laser scanning.

Resolution characterization of a silicon-based, photon-counting computed tomography prototype capable of patient scanning.

Photon-counting detectors are expected to bring a range of improvements to patient imaging with x-ray computed tomography (CT). One is higher spatial resolution. We demonstrate the resolution obtained using a commercial CT scanner where the original energy-integrating detector has been replaced by a single-slice, silicon-based, photon-counting detector. This prototype constitutes the first full-field-of-view silicon-based CT scanner capable of patient scanning. First, the pixel response function and focal spot profile are measured and, combining the two, the system modulation transfer function is calculated. Second, the prototype is used to scan a resolution phantom and a skull phantom. The resolution images are compared to images from a state-of-the-art CT scanner. The comparison shows that for the prototype are detectable with the same clarity as on the reference scanner at equal dose and reconstruction grid, with more line pairs visible with increasing dose and decreasing image pixel size. The high spatial resolution remains evident in the anatomy of the skull phantom and is comparable to that of other photon-counting CT prototypes present in the literature. We conclude that the deep silicon-based detector used in our study could provide improved spatial resolution in patient imaging without increasing the x-ray dose.

P1501Can we measure the stiffening of hypertensive hearts non-invasively? A shear wave imaging study using ultra-high frame rate echocardiography

Abstract Background Cardiac shear wave (SW) elastography is a novel technique based on high-frame-rate (HFR) echocardiography which has been shown to be related to myocardial stiffness. In this study we explore the relation between myocardial SW velocity and myocardial remodelling in remodelled hearts of patients with arterial hypertension (AH). Methods We prospectively included 33 treated AH patients with hypertrophic left ventricular (LV) remodelling (59±14 years, 55% male) and 26 aged matched healthy controls (55±15 years, 77% male). AH patients were further divided according to their LV geometric pattern into a concentric remodelling (CR) group (13 patients) and a concentric hypertrophy (CH) group (20 patients). LV parasternal long axis views were acquired with an experimental HFR ultrasound scanner (HD-PULSE) at 1266±317 frames per seconds. Myocardial acceleration maps were created from the HFR-datasets and an anatomical M-mode line was drawn along the midline of the interventricular septum (IVS). The propagation velocity of natural SWs occurring at mitral valve closure (MVC) was measured on these M-modes (Figure A) in order to assess passive myocardial stiffness. Standard echocardiography using a commercial scanner was performed to evaluate LV remodelling. Results SW velocities at MVC differed significantly between AH patients and controls (5.83±1.20 m/s vs. 4.04±0.96 m/s; p&lt;0.001). Within the patient group, patients with CH had highest SW velocities at MVC (p&lt;0.001), whereas values between controls and patients with CR were comparable (p=0.075) (Figure B). In AH patients, significant positive correlations were found between SW velocity at MVC and parameters of LV remodelling (IVS thickness: r=0.728, p&lt;0.001; LV mass index: r=0.780, p&lt;0.001, LV end-diastolic volume: r=0.604, p=0.008) (Figure C) and also parameters of diastolic function (E/e': r=0.495, p=0.005, left atrium diameter: r=0.866, p&lt;0.001, left atrium volume index: r=0.661, p&lt;0.001). Figure A, B, C Conclusions SW velocity – and therefore myocardial stiffness – is higher in AH patients compared to healthy controls and increases with increasing severity of hypertensive heart disease. Patients with concentric remodelling have still close-to-normal passive myocardial properties while patients with concentric hypertrophy show significant stiffening. Echocardiographic shear wave elastography is a promising new technique for the non-invasive assessment of myocardial stiffness and might provide valuable new insights into myocardial function and the pathophysiology of myocardial disease.

Iron embedded magnetic nanodiamonds for in vivo MRI contrast enhancement

Although nanodiamonds have long being considered as a potential tool for biomedical research, the practical in vivo magnetic resonance imaging (MRI) application of nanodiamonds remains relatively unexplored. In this paper, we present the first application of in vivo MRI contrast enhancement using only iron embedded magnetic nanodiamonds. An MR image enhancement was clearly demonstrated in the rendering of T2-weighted images of mice obtained using an unmodified commercial MRI scanner. The excellent contrast obtained using these nanodiamonds opens the door to the non-invasive in vivo tracking of nanodiamonds and image enhancement. In the future, one can apply these magnetic nanodiamonds together with surface modifications to facilitate drug delivery, targeted therapy, localized thermal treatment, and diagnostic imaging.

High-Throughput PET/CT Imaging Using a Multiple-Mouse Imaging System.

A considerable limitation of current small-animal PET/CT imaging is the low throughput of acquisitions. Consequently, to sufficiently power a study, high costs accumulate. Together with a commercial scanner manufacturer, we developed a 4-bed mouse “hotel” to simultaneously image up to 4 mice, thereby reducing costs and maximizing the efficiency of radiotracer use when compared with scans performed with a single mouse bed. Methods: For physiologic evaluation of the mouse hotel, temperature and anesthesia were tested for uniformity in conjunction with 18F-FDG PET/CT imaging of mini image-quality phantoms designed to fit the new imaging system. After reconstruction, National Electrical Manufacturers Association NU-4 tests examined uniformity, recovery coefficients, and spillover ratios. To evaluate the mouse hotel under standard in vivo imaging conditions, 4 mice were simultaneously scanned by dynamic 18F-FDG PET/CT over 60 min, and quantified images were compared with those acquired using a single mouse bed. Results: The mouse hotel maintained a constant temperature of 36.8°C ± 0.4°C, with anesthesia distributed evenly to each nose cone (2.9 ± 0.1 L/min). The National Electrical Manufacturers Association tests revealed values within tolerable limits for uniformity, for recovery coefficients in rods larger than 2 mm, and for spillover ratios in the nonradioactive water- and air-filled chambers. There was low variability in radiotracer uptake in all major organs for the mouse hotel versus the single mouse bed. Conclusion: Analysis of images acquired using the mouse hotel confirmed its utility to increase the throughput of small-animal PET imaging without considerable loss of image quality or quantitative precision. In comparison to a single mouse bed, the cost and time associated with each scan were substantially reduced.

Easy and Low-cost Chitosan Cryogel-based Colorimetric Biosensor for Detection of Glucose

A colorimetric biosensor for glucose detection has been studied based on chitosan cryogel supporting material for enzyme immobilization. The detection was based on the glucose conversion to hydrogen peroxide by glucose oxidase, then a titanium(IV) oxysulfate was used to measure hydrogen peroxide, indicated by the formation of yellow color. The color change with the concentration was then recorded by a commercial scanner and analyzed using an ImageJ software. The fabricated biosensor allows to easily prepare by in-tips enzyme immobilization with user-friendly operating using micropipette by the suck-hold-release method for the determination of glucose. Enzyme immobilization has been optimized including the amount of enzyme and the reaction time. The biosensor showed a high operational stability for up to 56 measurements using a single immobilized enzyme, with a wide linear range (0.3 to 3.0 mM glucose), high specificity, and also agreed with the standard method used in hospitals to detect blood glucose (the Wilcoxon signed-rank test, P > 0.05).

Preliminary investigation of a reusable radiochromic sheet for radiation dosimetry

This work investigates a novel reusable radiochromic sheet developed as an economic film substitute or as a radiochromic bolus. The radiation-induced optical density (OD) change of the sheet is read-out with a commercial flat-bed optical scanner. An optimized readout procedure was developed including an optimal scan-time window. Fundamental radiochromic properties of the sheets were characterized including temporal decay of OD, dose sensitivity and consistency through repeated irradiations, and temperature sensitivity. The radiation induced OD change in the sheets was found to decay to baseline within ~24 hours, after which the sheet could be reused. The sensitivity of subsequent re-irradiations was found to be consistent within ±5% (coefficient of variation of 4.5%) for at least 6 irradiations and potentially many more. Importantly, the sheets were not observed to carry any detectable memory of previous irradiations within measurement uncertainty. In conclusion, the Presage sheets show promise as an economic multi-purpose alternative for film applications and potentially as a radiochromic bolus. Further work is required to test the sheet in diverse clinical applications, and to develop a softer material for bolus applications.

Systematic analysis of bias and variability of texture measurements in computed tomography

Texture is a key radiomics measurement for quantification of disease and disease progression. The sensitivity of the measurements to image acquisition, however, is uncertain. We assessed bias and variability of computed tomography (CT) texture feature measurements across many clinical image acquisition settings and reconstruction algorithms. Diverse, anatomically informed textures (texture A, B, and C) were simulated across 1188 clinically relevant CT imaging conditions representing four in-plane pixel sizes (0.4, 0.5, 0.7, and 0.9mm), three slice thicknesses (0.625, 1.25, and 2.5mm), three dose levels ( 1.90, 3.75, and 7.50 mGy), and 33 reconstruction kernels. Imaging conditions corresponded to noise and resolution properties representative of five commercial scanners (GE LightSpeed VCT, GE Discovery 750 HD, GE Revolution, Siemens Definition Flash, and Siemens Force) in filtered backprojection and iterative reconstruction. About 21 texture features were calculated and compared between the ground-truth phantom (i.e., preimaging) and its corresponding images. Each feature was measured with four unique volumes of interest (VOIs) sizes (244, 579, 1000, and . To characterize the bias, the percentage relative difference [PRD(%)] in each feature was calculated between the imaged scenario and the ground truth for all VOI sizes. Feature variability was assessed in terms of (1) indicating the variability between the ground truth and simulated image scenario based on the PRD(%), (2) indicating the simulation-based variability, and (3) indicating the natural variability present in the ground-truth phantom. The PRD ranged widely from to 1220%, with an underlying variability ( ) of up to 241%. Features such as gray-level nonuniformity, texture entropy, sum average, and homogeneity exhibited low susceptibility to reconstruction kernel effects ( ) with relatively small ( ) across imaging conditions. The dynamic range of results indicates that image acquisition and reconstruction conditions of in-plane pixel sizes, slice thicknesses, dose levels, and reconstruction kernels can lead to significant bias and variability in feature measurements.

Hybrid organosilicon/polyol phantom for photoacoustic imaging.

The rapid development of hardware and software for photoacoustic technologies is urging the establishment of dedicated tools for standardization and performance assessment. In particular, the fabrication of anatomical phantoms for photoacoustic imaging remains an open question, as current solutions have not yet gained unanimous support. Here, we propose that a hybrid material made of a water-in-oil emulsion of glycerol and polydimethylsiloxane may represent a versatile platform to host a broad taxonomy of hydrophobic and hydrophilic dyes and recapitulate the optical and acoustic features of bio tissue. For a full optical parameterization, we refer to Wróbel, et al. [ Biomed. Opt. Express7, 2088 (2016)], where this material was first presented for optical imaging. Instead, here, we complete the picture and find that its speed of sound and acoustic attenuation resemble those of pure polydimethylsiloxane, i.e. respectively 1150 ± 30 m/s and 3.5 ± 0.4 dB/(MHz·cm). We demonstrate its use under a commercial B-mode scanner and a home-made A-mode stage for photoacoustic analysis to retrieve the ground-truth encoded in a multilayer architecture containing indocyanine green, plasmonic particles and red blood cells. Finally, we verify the stability of its acoustic, optical and geometric features over a time span of three months.

3D rigid-body motion information from spherical Lissajous navigators at small k-space radii: A proof of concept.

To demonstrate, for the first time, the feasibility of obtaining low-latency 3D rigid-body motion information from spherical Lissajous navigators acquired at extremely small k-space radii, which has significant advantages compared with previous techniques. A spherical navigator concept is proposed in which the surface of a k-space sphere is sampled on a 3D Lissajous curve at a radius of 0.1/cm. The navigator only uses a single excitation and is acquired in less than 5 ms. Rotation estimations were calculated with an algorithm from computer vision that exploits a rotation theorem of the spherical harmonics transform and has minimal computational cost. The effectiveness of the concept was investigated with phantom and in vivo measurements on a commercial 3T MRI scanner. Scanner-induced in vivo motion was measured with maximum absolute errors of 0.58° and 0.33 mm for rotations and translations, respectively. In the case of real, in vivo motion, the proposed method showed good agreement with motion information from FSL image registrations (mean/maximum deviations of 0.37°/1.24° and 0.44 mm/1.35 mm). In addition, phantom measurements indicated precisions of 0.014° and 0.013 mm. The computations for complete motion information took, on average, 24 ms on an ordinary laptop. This work demonstrates a proof of concept for obtaining accurate motion information from small-radius spherical navigators. The method has the potential to overcome several previously reported problems and could help increase the utility of navigator-based motion correction both in research and in the clinic.

Evaluation of an ELISA-based visualization microarray chip technique for the detection of veterinary antibiotics in milk

Antibiotics are increasingly found in dairy products. To ensure consumer safety, rapid screening methods which are accurate and cost-effective are highly in demand. A multiplexed detection technology was tested for quantification of these four kinds of antibiotics simultaneously in milk. The visual microarray technology based on enzyme-linked immunosorbent assays was utilized in this method, which can detect multiple target molecules simultaneously. This colorimetric technology provides direct results that can be detected using common commercial microplate scanners. The limit of detection (LOD) were calculated as 3.30, 3.39, 2.42 and 4.88 μg kg−1 for quinolones, tetracycline, lincomycin and streptomycin, respectively. The limits of quantity (LOQ) were defined as 8.97, 8.43, 5.36 and 10.97 μg kg−1 for quinolones, tetracycline, lincomycin and streptomycin, respectively. The accuracy of method was also adequate for these four substances with the recovery rates ranging from 77.6% to 116.4% were obtained for the detection of practical samples. According to our evaluation, this methodology can be used for rapid screening of antibiotics in internal quality control programs in dairy industry.