GE Images Research Articles

The therapeutic utility of combining dynamic contrast-enhanced magnetic resonance imaging with arterial spin labeling in the staging of nasopharyngeal carcinoma

BackgroundTo research the pathological and clinical staging uses of arterial spin labeling (ASL) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).Materials and methods64 newly diagnosed nasopharyngeal carcinoma (NPC) patients were enrolled from December 2020 to January 2022, and 3.0 T MRI (Discovery 750W, GE Healthcare, USA) were used for ASL and DCE-MRI scans. The DCE-MRI and ASL raw data were processed post-acquisition on the GE image processing workstation (GE Healthcare, ADW 4.7, USA). The volume transfer constant (Ktrans), blood flow (BF), and accompanying pseudo-color images were generated automatically. Draw the region of interest (ROIs), and the Ktrans and BF values for each ROI were recorded separately. Based on pathological information and the most recent AJCC staging criteria, patients were divided into low T stage groups = T1–2 and high T stage groups = T3–4, low N stage groups = N0–1 and high N stage groups = N2–3, and low AJCC stage group = stage I–II and high AJCC stage group = stage III–IV. The association between the Ktranst and BF parameters and the T, N, and AJCC stages was compared using an independent sample t-test. Using a receiver operating characteristic (ROC) curve, the sensitivity, specificity, and AUC of Ktranst, BFt, and their combined use in T and AJCC staging of NPC were investigated and assessed.ResultThe tumor-BF (BFt) (t = − 4.905, P < 0.001) and tumor-Ktrans (Ktranst) (t = − 3.113, P = 0.003) in the high T stage group were significantly higher than those in the low T stage group. The Ktranst in the high N stage group was significantly higher than that in the low N stage group (t = − 2.071, P = 0.042). The BFt (t = − 3.949, P < 0.001) and Ktranst (t = − 4.467, P < 0.001) in the high AJCC stage group were significantly higher than those in the low AJCC stage group. BFt was moderately positively correlated with the T stage (r = 0.529, P < 0.001) and AJCC stage (r = 0.445, P < 0.001). Ktranst was moderately positively correlated with T staging (r = 0.368), N staging (r = 0.254), and AJCC staging (r = 0.411). There was also a positive correlation between BF and Ktrans in gross tumor volume (GTV) (r = 0.540, P < 0.001), parotid (r = 0.323, P < 0.009) and lateral pterygoid muscle (r = 0.445, P < 0.001). The sensitivity of the combined application of Ktranst and BFt for AJCC staging increased from 76.5 and 78.4 to 86.3%, and the AUC value increased from 0.795 and 0.819 to 0.843, respectively.ConclusionCombining Ktrans and BF measures may make it possible to identify the clinical stages in NPC patients.

Tailored magnetic resonance fingerprinting

Neuroimaging of certain pathologies requires both multi-parametric qualitative and quantitative imaging. The role of the quantitative MRI (qMRI) is well accepted but suffers from long acquisition times leading to patient discomfort, especially in geriatric and pediatric patients. Previous studies show that synthetic MRI can be used in order to reduce the scan time and provide qMRI as well as multi-contrast data. However, this approach suffers from artifacts such as partial volume and flow. In order to increase the scan efficiency (the number of contrasts and quantitative maps acquired per unit time), we designed, simulated, and demonstrated rapid, simultaneous, multi-contrast qualitative (T1 weighted, T1 fluid attenuated inversion recovery (FLAIR), T2 weighted, water, and fat), and quantitative imaging (T1 and T2 maps) through the approach of tailored MR fingerprinting (TMRF) to cover whole-brain in approximately four minutes.We performed TMRF on in vivo four healthy human brains and in vitro ISMRM/NIST phantom and compared with vendor supplied gold standard (GS) and MRF sequences. All scans were performed on a 3 T GE Premier system and images were reconstructed offline using MATLAB. The reconstructed qualitative images were then subjected to custom DL denoising and gradient anisotropic diffusion denoising. The quantitative tissue parametric maps were reconstructed using a dense neural network to gain computational speed compared to dictionary matching. The grey matter and white matter tissues in qualitative and quantitative data for the in vivo datasets were segmented semi-automatically. The SNR and mean contrasts were plotted and compared across all three methods. The GS images show better SNR in all four subjects compared to MRF and TMRF (GS > TMRF>MRF). The T1 and T2 values of MRF are relatively overestimated as compared to GS and TMRF. The scan efficiency for TMRF is 1.72 min−1 which is higher compared to GS (0.32 min−1) and MRF (0.90 min−1).

Individual Tree Species Classification Based on a Hierarchical Convolutional Neural Network and Multitemporal Google Earth Images

Accurate and efficient individual tree species (ITS) classification is the basis of fine forest resource management. It is a challenge to classify individual tree species in dense forests using remote sensing imagery. In order to solve this problem, a new ITS classification method was proposed in this study, in which a hierarchical convolutional neural network (H-CNN) model and multi-temporal high-resolution Google Earth images were employed. In an experiment conducted in a forest park in Beijing, China, GE images of several significant phenological phases of broad-leaved forests, namely, before and after the mushrooming period, the growth period, and the wilting period, were selected, and ITS classifications based on these images along with several typical CNN models and the H-CNN model were conducted. In the experiment, the classification accuracy of the multitemporal images was higher by 7.08–12.09% than those of the single-temporal images, and the H-CNN model offered an OA accuracy 2.66–3.72% higher than individual CNN models, demonstrating that multitemporal images rich in the phenological features of individual tree species, together with a hierarchical CNN model, can effectively improve ITS classification.

Spatio-Temporal Evolution of Sandy Land and its Impact on Soil Wind Erosion in the Kubuqi Desert in Recent 30 Years

Continuous remote-sensing monitoring of sand in desert areas and the exploration of the spatio–temporal evolution characteristics of soil–wind erosion has an important scientific value for desertification prevention and ecological restoration. In this study, the Kubuqi Desert was selected as the study area, and the Landsat series satellite remote sensing data, supplemented by satellite remote sensing data such as GE images, SPOT-5, ZY-3, GF-1/2/6, etc., integrated object-oriented, decision tree, and auxiliary human–computer interaction interpretation methods, developed the Kubuqi Desert area dataset from 1990 to 2020, and established a soil erosion intensity database of the past 30 years based on the soil–wind erosion correction equation. The results show that the application of the training samples obtained by a high-score collaborative ground sampling to land use/cover classification in desert areas can effectively improve the efficiency of remote-sensing mapping of sand changes and the accuracy of change information identification, and the overall accuracy of the classification results is 95%. In general, the sandy area of the Kubuqi Desert area has decreased year by year, during which the mobile sand in the hinterland of the desert has expanded in a scattered distribution. The overall soil–wind erosion intensity showed a downward trend, especially since 2000; the ecological improvement trend after the implementation of desertification control projects is obvious. Changes in the sand type contributed the most to the reduction of soil–wind erosion intensity (contribution 81.14%), ecological restoration played a key role in reducing the soil–wind erosion intensity (contribution 14.42%), and the increase of forest and grass vegetation covers and agricultural oases played a positive role in solidifying the soil- and wind-proof sand fixation. The pattern of sandy land changes in desert areas is closely related to the national ecological civilization construction policy and the impact of climate change.

Artifacts in contrast-enhanced mammography: are there differences between vendors?

PurposeContrast-Enhanced Mammography (CEM) produces a dual-energy subtracted (DES) image that demonstrates iodine uptake (neovascularity) in breast tissue. We aim to review a range of artifacts on DES images produced using equipment from two different vendors and compare their incidence and subjective severity. MethodsWe retrospectively reviewed CEM studies performed between September 2013 and March 2017 using GE Senographe Essential (n = 100) and Hologic Selenia Dimensions (n = 100) equipment. Artifacts were categorized and graded in severity by a subspecialist breast radiologist and one of two medical imaging technologists in consensus. The incidence of artifacts between vendors was compared by calculating the relative risk, and the severity gradings were compared using a Wilcoxon rank-sum test. ResultsElephant rind, corrugations and the black line on chest wall artifact were seen exclusively in Hologic images.Artifacts such as cloudy fat, negative rim around lesion and white line on pectoral muscle were seen in significantly more Hologic images (p < 0.05) whilst halo, ripple, skin line enhancement, black line on pectoral muscle, bright pectorals, chest wall high-lighting and air gap were seen in significantly more GE images (p < 0.05).The severity gradings for cloudy fat had a significantly higher mean rank in Hologic images (p < 0.001) whilst halo and ripple artifacts had a significantly higher mean rank in GE images (p < 0.001 and p = 0.028 respectively). ConclusionThe type, incidence and subjective severity of CEM-specific artifacts differ between vendors. Further research is needed, but differences in algorithms used to produce the DE image are postulated to be a significant contributor.

Growth of High Sn Concentration Germanium-Tin Films on Insulators by Microsecond Laser Annealing

1. IntroductionThanks to their high carrier mobility, germanium based group IV semiconductors are promising materials to realize next generation electronics [1]. Especially, germanium tin alloys (GeSn) having high Sn concentration (> 6 at. %) are attracting much attention due to their direct band structure [2]. To apply such significant advantage to thin-film devices such as thin-film transistors (TFTs) or three dimensional large-scale integrated circuits (3D-LSIs), various groups are working on to crystallize these materials on insulating substrates by various approaches such as germanium condensation [3], solid phase crystallization [4], and so on.Recently, we have established a technique to grow highly strained germanium based materials on insulating substrates by microsecond annealing using novel high speed continuous wave laser annealing (CWLA) system [5]. Here, in this presentation, we will introduce our recent achievements in GeSn crystal growth by the microsecond annealing technique.2. Experimental ProcedureIn the experiment, amorphous GeSn films with Sn concentration of 15% (thickness: 100 nm) were firstly deposited on quartz substrates by molecular beam deposition. Then the samples were annealed by the high speed CWLA system, which can scan laser light (focused to 20 μm diameter) on samples with very high speed up to 15 m/s. The laser irradiation time (tirr) can be varied from 1.5 to 6.0 μs by controlling the scanning speed. Here, Nd:YVO4 solid state laser with wavelength of 532 nm was used as a light source, and laser power was controlled from 350 to 1000 mW. After the laser annealing, the samples were characterized by microscopic Raman spectroscopy and electron back scattered diffraction (EBSD) method.3. Results and DiscussionsFig. 1(a) shows Nomarski microscopic image after laser annealing (500 mW, tirr: 1.5 μs), which shows bright contrast at annealed region. Raman signals measured at surface of GeSn thin film before and after LA (tirr: 1.5 μs) are shown in Fig. 1(b). We can see clear peak around 300 cm-1 due to Ge-Ge atomic bond at the annealed region, which supports that GeSn film has been successfully crystallized by the annealing.To discuss about the growth feature of GeSn films, EBSD measurements were carried out. Mapping images of Ge and Sn phase signals at surfaces of samples are summarized in Fig. 2 as a function of tirr. Here, we can clearly see that the area of Sn phase signal is expanding by increasing tirr. These results (Raman and EBSD) suggest that by increasing tirr, Sn precipitation toward surface of GeSn occurs after crystallization of GeSn films, due to excess annealing. As a result, by increasing tirr, substitutional Sn concentration in the films decreases after LA [Fig. 3], showing that short time annealing is essential to prevent the precipitations. Fig. 4 summarizes substitutional Sn concentration in GeSn films grown with shortest irradiation time (1.5 μs) as a function of laser power. By minimizing the irradiation time and tuning laser power to minimum value for crystallization, we could realize GeSn thin films with a high substitutional Sn concentration (13 %) on insulating substrates. These are very attracting results to realize next generation electronics.Detailed physics and further tin concentration improvement methods will be discussed in the presentation.[References][1] J.R. Haynes, W. Shockley, Phys. Rev. 81 835–843 (1951).[2] S. Gupta, K. C. Saraswat, et.al., J. Appl. Phys. 113 073707 (2013).[3] S. Nakaharai, S. Takagi, et. al., J. Appl. Phys. 105 024515 (2009).[4] K. Toko, et. al., Sci. Rep., 7, 16981 (2017)[5] R. Matsumura, N. Fukata, ECS J. Solid State Sci. Technol, 9 063002 (2020). Figure 1

282 Advantage and Validation of Vendor-Independent Software for Global and Regional Strain Analysis

One of the main limitations for incorporating strain imaging into widespread clinical practice is inter-vendor incompatibility. This study sought to compare the variability of two-dimensional speckle-tracking derived global and regional longitudinal strain using vendor-specific software (VSS) and vendor-independent software (VIS) from images acquired by two different commercially available high-end ultrasound systems. 40 subjects underwent two sequential echocardiographic acquisitions using two different ultrasound systems (GE Vivid E9 and Philips iE33). Global longitudinal strain (GLS) and regional peak longitudinal strain were derived using VSS (EchoPAC BT 13 and QLAB version 10.3) and VIS (TomTec Image Arena version 4.6). Agreement (Blan-Altman Bias) and reproducibility of strain values between VSS and VIS were assessed using intraclass correlation coefficient (ICC). GLS values analysed by VIS on images acquired on different ultrasound systems showed no significant difference (TomTec strain analysis on GE images; -18.6±4.8 vs TomTec strain analysis on Philips images; -19.2±4.8, p=0.09). VIS GLS was comparable to VSS GLS, whilst regional strain was lower in agreement compared to GLS. There was good overall agreement using VIS for GLS (Bias: Philips images =-0.02, Bias: GE images =-0.91) and high inter- and intra-observer reproducibility (Interobserver ICC =0.92, Intraobserver ICC =0.96). VIS provides good agreement with VSS for GLS. Variability exists for regional strain between VIS and VSS. Good agreement for VIS strain values from images acquired using different ultrasound systems suggest VIS could potentially be useful for serial follow-up of GLS.

Imaging empty states on the Ge(100) surface at 12 K

Our understanding of bias-dependent scanning-tunneling-microscopy (STM) images is complicated not only by the multiplicity of the surface electronic structure, but also the manifold tunneling effects in probing semiconductor surfaces having directional dangling- and covalent-bond orbitals. Here we present a refined interpretation of empty-state STM images from the model semiconductor surface, Ge(100), on the basis of measurements at low temperature (12 K) combined with density-functional-theory calculations. In the lower-bias regime ($\ensuremath{\le}1.6\phantom{\rule{0.16em}{0ex}}\mathrm{V}$), the electron tunneling is found to occur predominantly in antibonding dangling-bond or/and dimer-bond states (${\ensuremath{\pi}}_{1}^{*},{\ensuremath{\pi}}_{2}^{*}$, and ${\ensuremath{\sigma}}^{*}$) of Ge(100) at the surface-parallel wave vector ${k}_{\ensuremath{\parallel}}=0$, leading to the tunneling current maxima located directly on the dimer rows. At higher biases (e.g., at 2 V), the current maxima are shifted to the position in the troughs between the dimer rows, because the tunneling occurs efficiently in the ${\ensuremath{\pi}}_{2}^{*}$ states at ${k}_{\ensuremath{\parallel}}\ensuremath{\ne}0$ associated with the dimer-up atoms of two adjacent dimer rows, i.e., because of increased sideways tunneling. Thus, the empty-state STM images of Ge(100), albeit strongly bias-dependent, reflect the dimer arrangement rather than the backbonds and surface resonances at all experimental conditions used. The results are also discussed in comparison with the counterpart system of Si(100).

Three-Dimensional Echocardiography-derived strain values acquired by a novel analysis program.

This in vitro study calculated longitudinal strain (LS) from different ultrasound systems (GE Vivid E9 and Philips IE 33) before and after myocardial infarct (MI) using a vendor-independent analysis software package (TomTec's 4D LV Analysis) to validate the variation of two ultrasound systems. Ten freshly harvested porcine hearts were passively driven by a pulsatile pump apparatus at stroke volumes (SV) 30-70mL. Full-volume three-dimensional echocardiography (3DE) data were acquired before and after MI using two different ultrasound systems. LS was derived from TomTec and validated against sonomicrometry data. Linear regression analyses showed excellent correlations between TomTec-calculated LS values and sonomicrometry data for both normal and simulated MI groups (GE: R2 =0.72/0.68, Philip: R2 =0.71/0.66). Bland-Altman analyses demonstrated overestimation of echo-derived strain values for all groups. Both ultrasound system-derived strain values demonstrated decreased LS after MI, and the average change in strain after infarct was roughly 30% in GE images and 25% in Philips images. Both GE and Philips echocardiographic systems can be analyzed with TomTec's program, and these images correlated well with sonomicrometry with acceptable variations.

BOLD-MRI demonstrates acute placental and fetal organ hypoperfusion with fetal brain sparing during hypercapnia

IntroductionWe evaluated changes in placental and fetal hemodynamics in rodents during acute hypercapnia using BOLD-MRI and Doppler ultrasound. MethodsAnimals were anesthetized with pentobarbital and, in consecutive 4-min periods, breathed: air, 21%O2:5%CO2, and 95%O2:5%CO2. BOLD-MRI: Pregnant ICR mice (n = 6; E17.5) were scanned in a 4.7-T Bruker Biospec spectrometer. Placenta and fetal liver, heart and brain were identified on True-FISP images. Percent change in signal intensity (SI) were analyzed every 30 s from T2*-weighted GE images (TR/TE = 147/10 ms). Doppler: Pregnant Wistar rats (n = 6; E18-20) were anesthetized with pentobarbital and received abdominal Doppler ultrasound. Umbilical artery pulsatility index (PI) and fetal heart rate were assessed at baseline and after two minutes of both hypercapnic challenges. ResultsBOLD-MRI: Normoxic-hypercapnia caused immediate marked reduction in SI in placenta (−44% ± 5.5; p < 0.001), fetal liver (−32% ± 6.4; p < 0.001) and fetal heart (−53% ± 9.9; p < 0.001) but only minor changes in fetal brain (−13% ± 3.4; p < 0.01), suggesting fetal brain sparing. Doppler: Normoxic-hypercapnia caused a marked increase in umbilical artery PI (+27.4% ± 7.2; p < 0.001) and a reduction in fetal heart rate (−48 bpm; 95%CI -9.3 to −87.0; p = 0.02), suggesting acute fetal asphyxia. ConclusionsBrief maternal hypercapnic challenge caused BOLD-MRI changes consistent with acute placental and fetal hypoperfusion with fetal brain sparing. The same challenge caused increased umbilical artery PI and fetal bradycardia on Doppler ultrasound, suggestive for acute fetal asphyxia. BOLD-MRI may be a suitable noninvasive imaging strategy to assess placental and fetal organ hemodynamics.

On the influence of the electron dose rate on the HRTEM image contrast

We investigate a possible dependence between the applied electron dose-rate and the magnitude of the resulting image contrast in HRTEM of inorganic crystalline objects. The present study is focussed on the question whether electron irradiation can induce excessively strong atom vibrations or displacements, which in turn could significantly reduce the resulting image contrast. For this purpose, high-resolution images of MgO, Ge, and Au samples were acquired with varying dose rates using a CS-corrected FEI Titan 80–300 microscope operated at 300kV accelerating voltage. This investigation shows that the magnitude of the signal contrast is independent from the dose rates occurring in conventional HRTEM experiments and that excessively strong vibrations or displacements of bulk atoms are not induced by the applied electron irradiation.

Measuring the Mutual Effects of a CZT Detector and a 3T MRI for the Development of a Simultaneous MBI/MRI Insert

A cadmium zinc telluride (CZT) based detector system has been developed with the goal of combining molecular breast imaging (MBI) and magnetic resonance imaging (MRI) to address shortcomings of each modality. The CZT detector system is comprised of four CZT modules tiled in a $2\times 2$ array. Each module consists of 256 pixels ( $16\times 16$ , 2.4 mm pixels) and features a built-in ASIC and FPGA. A custom digital readout circuit board was designed to interface the four modules with a microcontroller to a data acquisition PC. The system was placed within the bore of a 3 T GE Discovery MR750 and imaging performance of each modality evaluated using both sequential and simultaneous imaging protocols. The mean energy resolution of the gamma camera both inside and outside the MRI is 7.3% at 140 keV. The maximum increase in the integral uniformity was 3% when using a gradient echo MRI sequence while the mean differential uniformity when inside the MRI increased by 1%. Spatial resolution varied in a predictable manner from 2.4 mm FWHM at the collimator face to 6.9 mm at 10 cm from the collimator. Performance of the 3 T GE Discovery MR750 using a 16-channel breast RF coil array was measured with and without the gamma camera present using a gradient echo and spoiled gradient echo imaging sequence. A realistic 99mTc-filled breast-like phantom containing two lesions (30:1 lesion to background ratio) was used to assess the feasibility of both serial and simultaneous hybrid imaging. Sequential imaging resulted in a reduction in MRI SNR of 70-80% and a further decrease of 93-98% was observed when performing simultaneous MR/scintigraphy imaging, likely a result of RF interference originating from the CZT detector modules and associated analog electronics. Co-registered scintigraphic and MRI images display negligible geometric distortion when imaged with both simultaneous and serial imaging modes, thus indicating the feasibility of combining MBI with breast MRI.

Image texture and radiation dose properties in CT.

The aim of this study was to compare image noise properties of GE Discovery HD 750 and Toshiba Aquilion ONE. The uniformity section of a Catphan 600 image quality assurance phantom was scanned with both scanners, at different dose levels and with extension rings simulating patients of different sizes. 36 datasets were obtained and analyzed in terms of noise power spectrum. All the results prove that introduction of extension rings significantly altered the image quality with respect to noise properties. Without extension rings, the Toshiba scanner had lower total visible noise than GE (with GE as reference: FC18 had 82% and FC08 had 80% for 10 mGy, FC18 had 77% and FC08 74% for 15 mGy, FC18 had 80% and FC08 77% for 20 mGy). The total visible noise (TVN) for 20 and 15 mGy were similar for the phantom with the smallest additional extension ring, while Toshiba had higher TVN than GE for the 10 mGy dose level (120% FC18, 110% FC08). For the second and third ring, the GE images had lower TVN than Toshiba images for all dose levels (Toshiba TVN is greater than 155% for all cases). The results indicate that GE potentially has less image noise than Toshiba for larger patients. The Toshiba FC18 kernel had higher TVN than the Toshiba FC08 kernel with additional beam hardening correction for all dose levels and phantom sizes (120%, 107%, and 106% for FC18 compared to 110%, 98%, and 97%, for FC08, for 10, 15 and 20 mGy doses, respectively).PACS number(s): 87.57.Q‐, 87.57.nf, 87.57.C‐

A Novel Gaussian Extrapolation Approach for 2-D Gel Electrophoresis Saturated Protein Spots.

Analysis of images obtained from two-dimensional gel electrophoresis (2-D GE) is a topic of utmost importance in bioinformatics research, since commercial and academic software currently available have proven to be neither completely effective nor fully automatic, often requiring manual revision and refinement of computer generated matches. In this chapter, we present an effective technique for the detection and the reconstruction of over-saturated protein spots. Firstly, the algorithm reveals overexposed areas, where spots may be truncated, and plateau regions caused by smeared and overlapping spots. Next, it reconstructs the correct distribution of pixel values in these overexposed areas and plateau regions, using a two-dimensional least-squares fitting based on a generalized Gaussian distribution. Pixel correction in saturated and smeared spots allows more accurate proteins quantification, providing more reliable image analysis results. The method is validated for processing highly exposed 2-D GE images, comparing reconstructed spots with the corresponding non-saturated image. The results demonstrate that the algorithm enables correct spot quantification.

Proteomic research on diapause-related proteins in the female ladybird, Coccinella septempunctata L.

In the experiments reported here, we used the female ladybird Coccinella septempunctata L. as a model to identify diapause-associated proteins using proteomics technology. Our results indicated that protein expression patterns of diapausing and nondiapausing individuals were highly differentiated. A total of 58 spots showed significant differences in abundance (Ratio > 2 and P < 0.05) according to two-dimensional electrophoresis and GE Image Scanner III analysis. Sixteen protein spots were further investigated using mass spectrometry. Eight proteins were characterized, including chaperones and proteins involved in glucose metabolism, lipid metabolism, and the tricarboxylic acid cycle. Among these proteins, five proteins were upregulated in diapausing female adults, including a chaperone (Symbionin symL), malate dehydrogenase (putative), two proteins linked to lipid metabolism (unknown and conserved hypothetical protein) and phosphoglyceromutase (partial). By contrast, isocitrate dehydrogenase (RH49423p), fumarylacetoacetate hydrolase (AGAP001942-PA), and a putative medium chain acyl-CoA dehydrogenase were downregulated. These results contribute to the understanding of diapause mechanisms of the ladybird C. septempunctata and may suggest methods for improving the application of this natural enemy insect.

Highly accelerated Point-Spread Function mapping based on Finite Rate of Innovation for EPI distortion correction.

Hybrid MR-PET scans enable acquisition of both types of images within a session. Despite consistent subject positioning, image alignment can still be challenging. Functional MR images rely on echo-planar imaging (EPI) and present geometric distortions due to static B0 field inhomogeneities. Direct B0 [1] and Point Spread Function (PSF) mapping [2] (Figure ​(Figure1)1) have been proposed for distortion correction. The PSF method is more robust [3], but acquisition times are long even with previous acceleration approaches [4–7]. Figure 1 The PSF mapping sequence is repeated while varying the amplitude of the prewinder phase encode gradient (in red). We used the Finite Rate of Innovation (FRI) framework [8, 9] to detect the PSF peak position to sub-pixel precision using as few ks samples as possible. Images were acquired on a 3.0T Philips Achieva: 2.5×2.5×4.0 mm3, matrix 96×95, 95 ks steps with under-sampling retrospectively performed. PSF peak position was estimated using both the fully-sampled (zero-filled by a factor of 1000) and highly-undersampled data. To determine the PSF peak location, pattern matching was performed. The signal measured at each spatial location was compared to a predicted signal pattern accounting for the ks sampling scheme and the search progressively refined up to the intended precision. EPI images were undistorted as in [10]. Figure ​Figure22 shows example PSF peak shift maps (relative to expected undistorted positions). Figure ​Figure3A3A shows the original EPI slice matching Figure ​Figure2,2, and Figures 3B-E show the corrected images using each displacement map. Comparison with the GE image (Figure ​(Figure3F)3F) confirms accurate geometrical corrections. Figure 2 Maps of the PSF shifts (in pixels) estimated with: A0 2; B) 3; C) 4; D) all 95 ks Figure 3 EPI image (with corresponding outer contour in yellow); Undistorted EPI images estimating the displacement field from: B) 2; C) 3; D) 4 and E) all 95 ks samples and F) GE image (corresponding outer contour in yellow propagated to all undistorted EPI images) ... Using the proposed approach the position of the PSF peak can be estimated from a very small number of samples. In the future distortion map estimation could easily be incorporated into standard preparation phases. Making distortion correction of EPI images more practical would facilitate combining functional PET and MR information as well as structural connectivity information from diffusion-weighted MR images.

Imaging Features of Solitary Spinal Plasmacytoma in a Dog

A 12-year-old, intact, female Alaskan malamute presented with severe spinal pain and hind limb lameness. On radiographs, a round, demarcated lytic lesion was identified in the central fifth lumbar vertebra. On magnetic resonance imaging (MRI), the lesion involving the spinal cord appeared hypointense on T1 weighted, hyperintense on T2 weighted, heterogeneously enhanced on post-contrast T1 weighted, and hypointense on GE images. A focal, small, ill-defined, lytic lesion was also observed radiographically in the sixth lumbar vertebra, it appeared as a focal hyperintense lesion on T1 weighted, T2 weighted, and GE images and showed focal enhancement on post-contrast T1 weighted images. She was euthanized owing to extreme pain and severe and progressive clinical signs; a plasmacytoma was histopthologically diagnosed. This report presents an unusual type of spinal tumor, plasmacytoma. MRI is a useful modality to evaluate the anatomic location and extension of spinal lesions.

Structure Tensor Informed Fiber Tractography (STIFT) by combining gradient echo MRI and diffusion weighted imaging

Structural connectivity research in the human brain in vivo relies heavily on fiber tractography in diffusion-weighted MRI (DWI). The accurate mapping of white matter pathways would gain from images with a higher resolution than the typical ~2mm isotropic DWI voxel size. Recently, high field gradient echo MRI (GE) has attracted considerable attention for its detailed anatomical contrast even within the white and gray matter. Susceptibility differences between various fiber bundles give a contrast that might provide a useful representation of white matter architecture complementary to that offered by DWI. In this paper, Structure Tensor Informed Fiber Tractography (STIFT) is proposed as a method to combine DWI and GE. A data-adaptive structure tensor is calculated from the GE image to describe the morphology of fiber bundles. The structure tensor is incorporated in a tractography algorithm to modify the DWI-based tracking direction according to the contrast in the GE image. This GE structure tensor was shown to be informative for tractography. From closely spaced seedpoints (0.5mm) on both sides of the border of 1) the optic radiation and inferior longitudinal fasciculus 2) the cingulum and corpus callosum, STIFT fiber bundles were clearly separated in white matter and terminated in the anatomically correct areas. Reconstruction of the optic radiation with STIFT showed a larger anterior extent of Meyer's loop compared to a standard tractography alternative. STIFT in multifiber voxels yielded a reduction in crossing-over of streamlines from the cingulum to the adjacent corpus callosum, while tracking through the fiber crossings of the centrum semiovale was unaffected. The STIFT method improves the anatomical accuracy of tractography of various fiber tracts, such as the optic radiation and cingulum. Furthermore, it has been demonstrated that STIFT can differentiate between kissing and crossing fiber configurations. Future investigations are required to establish the applicability in more white matter pathways.

GE PAC and Image Processing Based on the Corn Automatically Grading System Design

The current corn classification is mainly handicraft. This method is low efficiency, labor intensive, and has failed to meet the requirements of production. This system unifies PAC and machine vision, designed a corn grading system. The whole system has configuration monitored and controlled by using machine PAC visual technology and Device Net field bus technology, the system has a safe and reliable operation, classicists accurately and rapidly. This system can significantly improve the efficiency and frozen corn sorted product quality, sort and speed over40 per minute, sorting accuracy can reach more than 99 percents. Demonstrates PAC technology in sorting system unique flexibility and expansibility, better realize the controlled object of automation control, has wide application prospects.

Assessment of Myocardial Deformation in Children Using Digital Imaging and Communications in Medicine (DICOM) Data and Vendor Independent Speckle Tracking Software

Analysis of myocardial deformation from data stored in Digital Imaging and Communications in Medicine format using vendor-independent software may be useful for clinical and research purposes but has not been evaluated in children. Grayscale images were prospectively acquired on Vivid 7 (GE Healthcare) and iE33 (Philips Medical Systems) ultrasound systems in 49 children. Digital Imaging and Communications in Medicine and raw data were analyzed using vendor-independent software (Cardiac Performance Analysis, Tomtec Imaging Systems) and vendor-specific software (EchoPAC and QLAB) and results compared. In addition, vendor-independent software using images at 30 frames/sec were compared with images at the higher acquisition frame rate. Measurement of short-axis radial and circumferential strain (ε) and apical four-chamber longitudinal εby vendor-independent software was possible in >92% of the children. Intraobserver and interobserver coefficients of variation for global circumferential and longitudinal ε ranged from 7.1% to 15.3% and for radial ε from 23.9% to 30.2%. Strain values were somewhat higher when using GE images at acquisition frame rates compared with ε values using GE images stored at 30 frames/sec. Strain values obtained by vendor-independent software were comparable with those obtained by vendor-specific software for longitudinal εand higher for circumferential ε. Radial ε values obtained by vendor-independent software were lower than ε values by EchoPAC and higher than ε values by QLAB. Vendor-independent software-derived ε is feasible and potentially valuable for measuring myocardial deformation in research and in multicenter studies using images from different ultrasound systems, especially for longitudinal deformation. However, a systematic bias for circumferential ε and a high variability in radial ε measurements remain concerns.