Segmentation of breast ultrasound images based on active contours using neutrosophic theory

Purpose

Ultrasound imaging is an effective approach for diagnosing breast cancer, but it is highly operator-dependent. Recent advances in computer-aided diagnosis have suggested that it can assist physicians in diagnosis. Definition of the region of interest before computer analysis is still needed. Since manual outlining of the tumor contour is tedious and time-consuming for a physician, developing an automatic segmentation method is important for clinical application.

Methods

The present paper represents a novel method to segment breast ultrasound images. It utilizes a combination of region-based active contour and neutrosophic theory to overcome the natural properties of ultrasound images including speckle noise and tissue-related textures. First, due to inherent speckle noise and low contrast of these images, we have utilized a non-local means filter and fuzzy logic method for denoising and image enhancement, respectively. This paper presents an improved weighted region-scalable active contour to segment breast ultrasound images using a new feature derived from neutrosophic theory.

Results

This method has been applied to 36 breast ultrasound images. It generates true-positive and false-positive results, and similarity of 95%, 6%, and 90%, respectively.

Conclusion

The purposed method indicates clear advantages over other conventional methods of active contour segmentation, i.e., region-scalable fitting energy and weighted region-scalable fitting energy.

     

Intravascular ultrasound-guided drug-eluting stent implantation is associated with improved clinical outcomes in patients with unstable angina and complex coronary artery true bifurcation lesions

Stenting coronary artery bifurcation lesion is associated with suboptimal clinical results. Clinical improvement by intravascular ultrasound (IVUS) guided bifurcation stenting is controversial because small-side-branch (SB), low-risk patients and false bifurcations were included in previous studies that had no exact IVUS criteria for optimal stent expansion. We sought determine whether IVUS guidance is superior to angiography guidance for patients with true and complex bifurcation lesions. Between July 2006 and July 2012, 1465 patients with unstable angina and Medina 1,1,1 or 0,1,1 coronary bifurcation lesions were prospectively studied. 310 patients in the IVUS guidance (defined as stent symmetry index?>?0.7, stent expansion index?>?0.9, well apposition, and no Type B/C dissection) group were paired with 620 patients in the angiography group by propensity score-matching. The primary endpoint was the rate of composite major adverse cardiac events (MACE) (cardiac death, myocardial infarction (MI), or clinically-driven target vessel revascularization) at 1-year and at the end of study after indexed procedure. Use of IVUS guidance was mainly driven by stenting technique selection and identification of lesions’ specificities. IVUS criteria for optimal stent expansion were achieved in 82.9% of patients which contribute to IVUS group data assessment and the rest did not meet optimal criteria. MACE occurred in 10.0% of patients at 1-year follow-up and 15.2% at the 7-year follow-up in the IVUS group, significantly different from 15.0% (p?=?0.036) and 22.4% (p?=?0.01) in the angiography group, respectively. Compared to angiography guidance, IVUS guidance also resulted in a lower 7-year cardiac death rate (6.5 versus 1.3%, p?=?0.002) and MI (8.4 versus 2.3%, P?<?0.001). Any revascularization was also statistically lower in the IVUS group through whole study period, compared to the angiography group. Lower MACE rates were observed in IVUS guidance group in a 7-year follow-up compared with angiography guidance alone.     

Impact of different annuloplasty rings on geometry of the mitral annulus with fibroelastic deficiency: the significance of aorto–mitral angle

We sought to investigate the impact of full annuloplasty rings versus C-shape bands on mitral annular geometry in the presence of fibroelastic deficiency (FED), as assessed by intraoperative three-dimensional transesophageal echocardiography (3DTEE). We retrospectively selected 65 patients who underwent mitral valve repair for severe mitral regurgitation caused by FED using full rings (the Ring group, n?=?30) and C-shape bands (the Band group, n?=?35). 71 controls without valvular heart disease were also included. Thorough 3DTEE inspections were performed for the entire cohort to measure morphological parameters of mitral annulus before and after surgery. Mid-term repair durability and left atrial diameter were followed up. The preoperative 3DTEE parameters, including annular diameters, area, height and aorto–mitral angle, were significantly larger in the FED groups than normal, and were comparable between two groups using different annuloplasty devices. After repair, the anterior–posterior diameter, annulus circumference and area were significantly larger in the Band group than in the Ring group. The aorto–mitral angle became comparable with normal value in the Ring group (p?=?0.728), but not in the Band group (p?=?0.011). Follow-up echocardiographic data showed a significant correlation between postoperative aorto–mitral angle and reduced left atrial diameter at 50.3 months after surgery (r?=?0.63; p?<?0.001). In conclusion, compared with C-shape bands, full rings may impose less narrowing on aorto–mitral angle, which correlates well with mid-term left atrial reverse remodeling.     

Raman photostability of off-resonant gap-enhanced Raman tags

Surface-enhanced Raman scattering (SERS) nanoprobes show promising potential for biosensing and bioimaging applications due to advantageous features of ultrahigh sensitivity and specificity. However, very limited research has been reported on the SERS photostability of nanoprobes upon continuous laser irradiation, which is critical for high-speed and time-lapse microscopy. The core–shell off-resonant gap-enhanced Raman tags (GERTs) with built-in Raman reporters, excited at near-infrared (NIR) region but with a plasmon resonance at visible region, allow decoupling the plasmon resonance behaviors with the SERS performance and therefore show ultrahigh Raman photostability during continuous laser irradiation. In this work, we have synthesized five types of off-resonant GERTs with different embedded Raman reporters, numbers of shell layer, or nanoparticle shapes. Via thorough examination of time-resolved SERS trajectories and quantitative analysis of photobleaching behaviors, we have demonstrated that double metallic-shell GERTs embedded with 1,4-benzenedithiol molecules show the best photostability performance, to the best of our knowledge, among all SERS nanoprobes reported before, with a photobleaching time constant up to 4.8 × 10⁵ under a laser power density of 4.7 × 10⁵ W cm⁻². Numerical calculations additionally support that the local plasmonic heating effect in fact can be greatly minimized using the off-resonance strategy. Moreover, double-shell BDT-GERTs are highly potential for high-speed and high-resolution Raman-based cell bioimaging.

Off-resonant gap-enhanced Raman tags (GERTs) show ultrahigh Raman enhancement and photostabilities and therefore can be used as ideal highly photostable nanoprobes for high-speed and high-resolution Raman bioimaging.

The surface-enhanced Raman scattering (SERS) effect strongly boosts the Raman signal of reporter molecules adsorbed on the surface of metallic plasmonic nanoparticles with the intense electromagnetic field enhancement.^1–7 With the unique fingerprint spectral feature, SERS nanoprobes, namely, metallic nanoparticles together with molecules as Raman reporters, have been extensively investigated for the biomedical applications including biosensing and bioimaging similar to the fluorescent nanoprobes.^8–14 In contrast to fluorophores, SERS nanoprobes exhibit a much larger multiplexing capability due to the narrow spectral linewidth. In addition, SERS nanoprobes show better stability than fluorophores since fluorophores easily suffer the photobleaching issue caused by modification of covalent bonds or non-specific reactions between the fluorophores and surrounding molecules upon singlet state-triplet state transition,^15,16 which is especially problematic in time-lapse microscopy.¹⁷ Typically the photobleaching in SERS nanoprobes does not follow this process and is much less problematic than that in fluorophores. It can be further minimized by decreasing the laser power and prolonging the laser exposure time. However, the photobleaching is still not favorable for high-contrast SERS-based bioimaging, which recently shows great potential for intraoperative precise identification of tumor margins and microscopic tumor invasion^18–21 and inevitably requires high-speed and a number of imaging cycles.Recently a new type of SERS nanoprobes, namely, gap-enhanced Raman tags (GERTs), have been reported to show excellent SERS enhancement,^7,22,23 which is favorable for high-speed SERS imaging.^13,22,24 GERTs are composed of plasmonic Au core–shell nanomatryoshka structures^25–27 with a uniform and nanometer-sized interior gap between the metallic core and the shell in addition to an external mesoporous silica layer if needed.²² Such nanoprobes show strong near-infrared (NIR) Raman enhancement due to the combined near-field electromagnetic and chemical enhancement in the subnanometer core–shell junction geometry while they only present one localized surface plasmon resonance (LSPR) in the visible range in the far-field spectrum.²⁷ Therefore GERTs with the built-in nanogap geometry allow decoupling the LSPR spectrum with the SERS performance. This off-resonance NIR excitation strategy is able to minimize the excitation laser induced photo-thermal effect to GERTs, leading to their ultrahigh SERS photostability during 30 min continuous cell and tumor SERS imaging without being photobleached.²² The off-resonant NIR GERTs as imaging probes are also favorable for generating minimal photothermal damage to the biological samples during the imaging process, as demonstrated by monitoring the changes in mitochondrial membrane potential of cancer cells during imaging.²⁸ The core–shell structure of GERTs additionally offers a variety of embedded Raman reporters and the numbers of shell layer,²⁹ but it remains a question and a challenge to understand how these factors of nanoprobe composition and morphology affect their SERS photostability.In this work, we synthesized five types of off-resonant GERTs either with different embedded Raman reporters (including 1,4-benzenedithiol (BDT), 4,4′-biphenyldithiol (BPDT), 4,4′-terphenyldithiol (TPDT), and 4-nitrobenzenethiol (NBT)), numbers of shell layer, or nanoparticle (NP) shapes. We have compared their particle morphologies, optical properties, and SERS photostability under continuous laser irradiation. Careful examination of time-resolved SERS trajectories and quantitative analysis of photobleaching behaviors indicate that double metallic-shell GERTs embedded with BDT molecules show the best photostability performance to the best of our knowledge. Numerical calculations are additionally performed to estimate the local laser-induced lattice temperature change of GERTs at on-resonance and off-resonance conditions. Further investigations of Raman-based cell imaging have demonstrated that those double-shell GERTs are great nanoprobes for high-speed and high-resolution Raman bioimaging.     

Performance and mechanism of free nitrous acid on the solubilization of waste activated sludge

Free nitrous acid (FNA) is a promising chemical reagent for excess sludge reduction. The distinctive properties of FNA treatment on waste activated sludge (WAS) disposal have previously been demonstrated, however, the cellular response, permeabilization, and disruption caused by low-concentration FNA and the direct cell solubilization of WAS using concentrated FNA should be better understood. In this study, the parameters that influence the sludge solubilization efficiency were optimized over a wide range of FNA concentrations. The sludge solubilization efficiency was found to be superior when the sludge was exposed to FNA (when the dosage of NaNO₂ was 0.12 g g⁻¹ TSS and the pH was 3.0, FNA = 20.94 mg L⁻¹) for 10 h at 25 °C, and the TSS removal and COD dissolution efficiencies were found to be prominent at 38% and 7%, respectively. In the FNA treatment of WAS, some FNA-tolerable cells increased the K⁺, Ca²⁺, and H⁺ effluxes under low concentrations of FNA, and finally achieved ion homeostasis based on the results using a scanning ion-selective electrode measurement technique. This could cause the cells in WAS to maintain cytoactivity and integrity under a low-concentration FNA treatment. Furthermore, flow cytometry was used to assess the permeabilization and disruption of sludge cells toward a concentration gradient of FNA. Flow cytometry results indicated that cells in sludge flocs were disrupted within 30 minutes when the FNA concentration was above 8 mg L⁻¹.

The mechanism of sludge solubilization induced by free nitrous acid over a large concentration range was investigated using SIET and FCM.     

中国儿童青少年代谢综合征患病率Meta分析

目的 通过Meta分析了解我国儿童青少年MS的流行现状, 为早期防治提供科学依据。 方法 检索2004-2014年在中国期刊全文数据库(CNKI)、万方数据资源系统(Wanfangdata)、维普数据库(VIP)及PubMed中收录的有关中国地区儿童青少年MS患病率研究的文献。根据加强观察性流行病学研究报告规范(STROBE)声明中横断面研究评价标准进行文献质量评价, 采用Stata 12.0软件进行数据合并估算患病率, 并对性别、体重状态等因素进行亚组分析, 采用漏斗图及Egger检验发表偏倚, 通过排除其中任意一篇文献对合并效应值的影响进行敏感性分析。 结果 共纳入19篇文献(5篇英文、14篇中文)。依据国际糖尿病联盟(IDF)标准、美国国家胆固醇教育计划成人治疗专家组Ⅲ修订(NCEPⅢ)标准、中国儿童青少年代谢综合征定义和防治建议(CHN2012)标准, 我国儿童青少年MS患病率分别为1.8%、2.6%及2.0%。按IDF标准, 男、女童MS患病率分别为2.9%、1.8%, 正常、超重、肥胖儿童中MS患病率分别为0.2%、4.7%、17.3%。NCEPⅢ标准、CHN2012标准结果均呈现男生MS患病率高于女生、肥胖组MS患病率> 超重组> 正常组。 结论 儿童青少年MS呈流行趋势, 应用不同诊断标准对MS检出率影响较大。肥胖是MS的重要危险因素, 因此应遏制肥胖, 对儿童超重、肥胖尽早识别干预, 以减少儿童MS的发生。     

江汉平原地方性砷中毒病区地下水砷含量变化及沉积物砷化学特征研究

目的 了解江汉平原地方性砷中毒(地砷病)病区地下水砷含量变化,探讨该区域高砷水赋存环境、地下水系统砷的来源.方法 在湖北省仙桃市和洪湖市分别以地砷病患者家为中心点,在3 km半径内各采集30份地下水样品和3个地质钻孔沉积物样芯;水砷含量比较采用配对t检验或配对符号秩和检验进行分析.结果 仙桃市南洪村2011－2012年水砷浓度低于2006－2007年(t=4.645 3,P< 0.000 1),洪湖市姚河村2011－2012年水砷浓度高于2006－2007年(S=-150,P< 0.000 1);高砷水呈弱酸、弱氧化性,水砷浓度与水样Cl^-、HCO₃^-、Fe、Mn浓度正相关,与水样SO₄^2-、NO₃^-浓度负相关;研究区沉积物中砷浓度为1.500～17.289 mg/kg,砷含量最大值均出现在泥土层,最小值均出现在沙层.结论 江汉平原地砷病病区高砷水砷含量的时空间变化程度较大,与中国山西大同盆地、山阴地区、内蒙古河套平原等原生高砷水地区有明显差异,为典型的高砷水赋存环境;研究区沉积物样品中砷含量与岩性结构有密切关系.