Compressed Sensing for Elastography in Portable Ultrasound

Bonghun Shin, Soo Jeon, Jeongwon Ryu and Hyock Ju Kwon, “Compressed Sensing for Elastography in Portable Ultrasound,” Ultrasonic Imaging, 39(6), pp. 393-413, Copyright © The Author(s) 2017. Reprinted by permission of SAGE Publications. https://doi.org/10.1177/0161734617716938Portable wireless ultrasound has many advantages such as high portability, easy connectivity, strong individuality, as well as on-site diagnostic ability in real-time. Some of the modern portable ultrasound devices offer high image quality and multiple ultrasound modes comparable to console style ultrasound, however, none of them provides ultrasound elastography function that enables the diagnosis of malignant legions using elastic properties. This is mainly due to the limitations of hardware performance and wireless data transfer speed for processing the large amount of data for elastography. Therefore, reduction of the data transfer size is one of the feasible solutions to overcome these limitations. Recently compressive sensing (CS) theory has been rigorously studied as a means to break the conventional Nyquist sampling rate and thus can significantly decrease the amount of measurement signals without sacrificing signal quality. In this research, we implemented various CS reconstruction frameworks and comparatively evaluated their reconstruction performance for realizing ultrasound elastography function on portable ultrasound. Combinations of three most common model bases (FT, DCT, and WA) and two reconstruction algorithms (l_1 minimization and BSBL) were considered for CS frameworks. Two kinds of numerical phantoms, echoic and elastography phantoms, were developed to evaluate performance of CS on B-mode images and elastograms, respectively. To assess the reconstruction quality, mean absolute error (MAE), signal-to-noise (SNRe) and contrast-to-noise (CNRe) were measured on the B-mode images and elastograms from CS reconstructions. Results suggest that CS reconstruction adopting BSBL algorithm with DCT model basis can yield the best results for all the measures tested, and the maximum data reduction rate for producing readily discernable elastograms is around 60%.Natural Sciences and Engineering Research Council || RGPIN-2015-05273, RGPIN-2015-04118, RGPAS-354703-201

Focused Ultrasound Surgery Of Breast Cancer: A Computational Study On A Realistic Patient Model

Focused ultrasound surgery (FUS) is a new energy-based therapeutic technique which has been recognized as a truly non-invasive surgical method. Since the ultrasonic energy is applied from an external transducer, FUS has the potential to improve both oncologic and cosmetic outcomes for breast cancer treatment. In the present study, we conducted a computational analysis on a realistic patient model to investigate the mechanism and the applicability of FUS in breast cancer treatment. Magnetic Resonance Imaging (MRI) data of a patient with breast tumor were used to provide a clinical model for finite element analysis (FEA) using COMSOL. Results from computational analysis clarify the acoustic and thermal mechanisms of FUS and suggest the way how this technique can be carried out during the breast cancer treatment

Elastography for Portable Ultrasound

This is a post-peer-review, pre-copyedit version of an article published in Biomedical Engineering Letters. The final authenticated version is available online at https://doi.org/10.1007/s13534-017-0052-1.Portable wireless ultrasound has been emerging as a new ultrasound device due to its unique advantages including small size, lightweight, wireless connectivity and affordability. Modern portable ultrasound devices can offer high quality sonogram images and even multiple ultrasound modes such as color Doppler, echocardiography, and endovaginal examination. However, none of them can provide elastography function yet due to the limitations in computational performance and data transfer speed of wireless communication. Also phase-based strain estimator (PSE) that is commonly used for conventional elastography cannot be adopted for portable ultrasound, because ultrasound parameters such as data dumping interval are varied significantly in the practice of portable ultrasound. Therefore, this research aims to propose a new elastography method suitable for portable ultrasound, called the robust phase-based strain estimator (RPSE), which is not only robust to the variation of ultrasound parameters but also computationally effective. Performance and suitability of RPSE were compared with other strain estimators including time-delay, displacement-gradient and phase-based strain estimators (TSE, DSE and PSE, respectively). Three types of raw RF data sets were used for validation tests: two numerical phantom data sets modeled by an open ultrasonic simulation code (Field II) and a commercial FEA (Abaqus), and the one experimentally acquired with a portable ultrasound device from a gelatin phantom. To assess image quality of elastograms, signal-to-noise (SNRe) and contrast-to-noise (CNRe) ratios were measured on the elastograms produced by each strain estimator. The computational efficiency was also estimated and compared. Results from the numerical phantom experiment showed that RPSE could achieve highest values of SNRe and CNRe (around 5.22 and 47.62 dB) among all strain estimators tested, and almost 10 times higher computational efficiency than TSE and DSE (around 0.06 vs. 5.76 seconds per frame for RPSE and TSE, respectively).Natural Sciences and Engineering Research Council || RGPIN-2015-05273, RGPIN-2015-04118 and RGPAS-354703-201

Rim 2/Hipa CACTA transposon display ; A new genetic marker technique in Oryza species

BACKGROUND: Transposons constitute the major fractions of repetitive sequences in eukaryotes, and have been crucial in the shaping of current genomes. Transposons are generally divided into two classes according to the mechanism underlying their transposition: RNA intermediate class 1 and DNA intermediate class 2. CACTA is a class 2 transposon superfamily, which is found exclusively in plants. As some transposons, including the CACTA superfamily, are highly abundant in plant species, and their nucleotide sequences are highly conserved within a family, they can be utilized as genetic markers, using a slightly modified version of the conventional AFLP protocol. Rim2 /Hipa is a CACTA transposon family having 16 bp consensus TIR sequences to be present in high copy numbers in rice genome. This research was carried out in order to develop a Rim2/Hipa CACTA-AFLP or Rim2/Hipa CACTA-TD (transposon display, hereafter Rim2/Hipa-TD) protocol for the study of genetic markers in map construction and the study of genetic diversity in rice. RESULTS: Rim2/Hipa-TD generated ample polymorphic profiles among the different rice accessions, and the amplification profiles were highly reproducible between different thermocyclers and Taq polymerases. These amplification profiles allowed for clear distinction between two different ecotypes, Japonica and Indica, of Oryza sativa. In the analysis of RIL populations, the Rim2/Hipa-TD markers were found to be segregated largely in a dominant manner, although in a few cases, non-parental bands were observed in the segregating populations. Upon linkage analysis, the Rim2/Hipa-TD markers were found to be distributed in the regions proximal to the centromeres of the chromosomes. The distribution of the Rim2/Hipa CACTA elements was surveyed in 15 different Oryza species via Rim2/Hipa-TD. While Rim2/Hipa-TD yielded ample amplification profiles between 100 to 700 bp in the AA diploid Oryza species, other species having BB, CC, EE, BBCC and CCDD, profiles demonstrated that most of the amplified fragments were larger than 400 bp, and that our methods were insufficient to clearly distinguish between these fragments. However, the overall amplification profiles between species in the Oryza genus were fully distinct. Phenetic relationships among the AA diploid Oryza species, as evidenced by the Rim2/Hipa-TD markers, were matched with their geographical distributions. CONCLUSION: The abundance of the Rim2/Hipa TIR sequences is very informative since the Rim2/Hipa-TD produced high polymorphic profiles with ample reproducibility within a species as well as between species in the Oryza genus. Therefore, Rim2/Hipa-TD markers can be useful in the development of high-density of genetic map around the centromeric regions. Rim2/Hipa-TD may also prove useful in evaluations of genetic variation and species relationships in the Oryza species

Hu.4-1BB-Fc fusion protein inhibits allergic inflammation and airway hyperresponsiveness in a murine model of asthma

Purpose4-1BB (CD 137) is a costimulatory molecule expressed on activated T-cells. Repression by 4-1BB is thought to attenuate Th2-mediated allergic reactions. The aim of this study was to investigate the effect of 4-1BB on allergic airway inflammation in a murine asthma model.MethodsBALB/c mice were sensitized to and challenged with ovalbumin (OVA). Hu.4-1BB-Fc was administered 1 day before the first OVA sensitization or 1 day after the second OVA sensitization. Following antigen challenge, airway responsiveness to methacholine was assessed and bronchoalveolar lavage (BAL) fluid was analyzed. Total immunoglobulin (Ig) E, OVA-specific IgE, IgG1, and IgG2a levels in sera were measured by enzyme-linked immunosorbent assay. Lung pathology was also evaluated.ResultsIn mice treated with Hu.4-1BB-Fc before the first OVA sensitization, there was a marked decrease in airway hyperresponsiveness, total cell count, and eosinophil count in the BAL fluid. In addition, Hu.4-1BB-Fc treatment decreased serum OVA-specific IgG1 levels and increased serum IgG2a level significantly compared with the corresponding levels in mice sensitized to and challenged with OVA. Hu.4-1BB-Fc-treated mice also showed suppressed peribronchial and perivascular inflammatory cell infiltration. In contrast, treatment with Hu.4-1BB-Fc 1 day after sensitization had no effect on airway hyperresponsiveness and showed less suppression of inflammation in lung tissue.ConclusionAdministration of Hu.4-1BB-Fc can attenuate airway inflammation and hyperreactivity in a mouse model of allergic airway inflammation. In addition, administration before sensitization may be more effective. These findings suggest that 4-1BB may be a useful therapeutic molecule against asthma

Additive Value of B-Type Natriuretic Peptide on Rest 201Tl-Dipyridamole Stress 99mTc-Sestamibi Gated Myocardial SPECT in Patients with Normal Left Ventricular Systolic Function

We evaluated whether BNP has additive value to SPECT in patients with normal left ventricular (LV) systolic function. Data from 224 consecutive patients who underwent rest 201Tl-dipyridamole stress 99mTc-sestamibi gated SPECT and coronary angiography due to chest pain were analyzed. Patients with true positive SPECT showed significant higher BNP level than those with false positive defect (38.5 (19.0–79.8) versus 19.0 (9.3–35.8), P = .01). Patients with true negative SPECT also showed significantly lower BNP level than those with false negative SPECT (39.0 (23.0–77.0) versus 22.0 (15.0–43.0), P = .002). In multivariate analyses, elevated BNP level (using a cut-off value of 23.0 pg/mL) was the strongest and independent predictor of CAD in overall patients (OR 2.75, 95% CI: 1.50–5.023, P = .001) and patients with positive SPECT (OR 3.34, 95% CI: 1.51–7.37, P = .003). The area under the receiver-operating characteristic curve for CAD in overall patients and patients with positive SPECT was 0.673 (95% CI: 0.603–0.743, P < .001) and 0.694 (95% CI: 0.602–0.786, P < .001), respectively. This study suggests that BNP level has additive diagnostic value to SPECT findings in predicting CAD in patients with normal LV systolic function

Antioxidant and Anti-Inflammatory Effects of Herbal Formula SC-E3 in Lipopolysaccharide-Stimulated RAW 264.7 Macrophages

SC-E3 is a novel herbal formula composed of five oriental medicinal herbs that are used to treat a wide range of inflammatory diseases in Korean traditional medicine. In this study, we sought to determine the effects of SC-E3 on free radical generation and inflammatory response in lipopolysaccharide- (LPS-) treated RAW 264.7 macrophages and the molecular mechanism involved. The ethanol extract of SC-E3 showed good free radical scavenging activity and inhibited LPS-induced reactive oxygen species generation. SC-E3 significantly inhibited the production of the LPS-induced inflammatory mediators, nitric oxide and prostaglandin E2, by suppressing the expressions of inducible nitric oxide synthase and cyclooxygenase-2, respectively. SC-E3 also prevented the secretion of the proinflammatory cytokines, IL-1β, TNF-α, and IL-6, and inhibited LPS-induced NF-κB activation and the mitogen-activated protein kinase (MAPK) pathway. Furthermore, SC-E3 induced the expression of heme oxygenase-1 (HO-1) by promoting the nuclear translocation and transactivation of Nrf2. Taken together, these results suggest that SC-E3 has potent antioxidant and anti-inflammatory effects and that these effects are due to the inhibitions of NF-κB and MAPK and the induction of Nrf2-mediated HO-1 expression in macrophages. These findings provide scientific evidence supporting the potential use of SC-E3 for the treatment and prevention of various inflammatory diseases

Dental students perception of their educational environment in relation to their satisfaction with dentistry major: a cross-sectional study

Abstract Background Students perception of their educational environment and satisfaction with their major can reveal the extent of their readiness to practice their profession after graduation. This study aimed to evaluate dental students perception of their educational environment and satisfaction with their major in dentistry, as well as the relationship between these two factors. Methods An online survey was conducted in 2022 among first- to fourth-year students across 11 dental schools in Korea. The Dundee Ready Education Environment Measure (DREEM) and Academic Major Satisfaction Scale (AMSS) were used to measure the students perception of the educational environment and satisfaction with their major in dentistry, respectively. Results A total of 539 students participated in the survey (response rate = 18.1%). The overall mean scores of the DREEM and AMSS were 125.03 (maximum score 200) and 22.01 (maximum score 30), respectively. Fourth-year students had the lowest scores in the overall DREEM, DREEM subscales (excluding students perceptions of atmosphere), and AMSS. The overall DREEM scores and all DREEM subscales showed statistically significant positive and moderate correlations with AMSS (p < 0.001). Conclusion Using the DREEM, we identified areas that need improvement and the academic year (fourth year) that require proactive support. Considering the positive correlation between all DREEM subscales and the AMSS, measures to comprehensively improve the educational environment are needed to improve dental students satisfaction with their major