超声弹性成像技术在乳腺肿块诊断中的研究进展及应用

超声弹性成像技术(UE)是一种新的超声成像技术,能够根据组织硬度进行成像,估计出组织内部的弹性信息,从而反映它的结构特点,该技术较传统触诊检查更加客观,在乳腺肿块的鉴别诊断中有较高的价值,其临床应用广泛并且得到了快速的发展。现就国内外文献对UE技术的原理、图像分析方法、技术研究进展及其在乳腺肿块鉴别诊断中的应用进行综述。     

Comparing Visually Assessed BI-RADS Breast Density and Automated Volumetric Breast Density Software: A Cross-Sectional Study in a Breast Cancer Screening Setting

Introduction

The objective of this study is to compare different methods for measuring breast density, both visual assessments and automated volumetric density, in a breast cancer screening setting. These measures could potentially be implemented in future screening programmes, in the context of personalised screening or screening evaluation.

Materials and Methods

Digital mammographic exams (N = 992) of women participating in the Dutch breast cancer screening programme (age 50–75y) in 2013 were included. Breast density was measured in three different ways: BI-RADS density (5^th edition) and with two commercially available automated software programs (Quantra and Volpara volumetric density). BI-RADS density (ordinal scale) was assessed by three radiologists. Quantra (v1.3) and Volpara (v1.5.0) provide continuous estimates. Different comparison methods were used, including Bland-Altman plots and correlation coefficients (e.g., intraclass correlation coefficient [ICC]).

Results

Based on the BI-RADS classification, 40.8% of the women had ‘heterogeneously or extremely dense’ breasts. The median volumetric percent density was 12.1% (IQR: 9.6–16.5) for Quantra, which was higher than the Volpara estimate (median 6.6%, IQR: 4.4–10.9). The mean difference between Quantra and Volpara was 5.19% (95% CI: 5.04–5.34) (ICC: 0.64). There was a clear increase in volumetric percent dense volume as BI-RADS density increased. The highest accuracy for predicting the presence of BI-RADS c+d (heterogeneously or extremely dense) was observed with a cut-off value of 8.0% for Volpara and 13.8% for Quantra.

Conclusion

Although there was no perfect agreement, there appeared to be a strong association between all three measures. Both volumetric density measures seem to be usable in breast cancer screening programmes, provided that the required data flow can be realized.     

Randomization in the Canadian National Breast Screening Study: a review for evidence of subversion

The authors assess the randomization strategy that had been used in the Canadian National Breast Screening Study (NBSS). Document experts at a private investigation and security company were hired to assist in reviewing instances in which names of subjects were altered in the "allocation books" (the basic instrument used to assign, at random, participants to either the mammography or the usual-care arm). The review was restricted to records from 3 NBSS centres where women assigned to the mammography arm had a distinctly higher (not necessarily significant) number of deaths from breast cancer than those assigned to the usual-care arm, and to records from 2 centres where, for limited periods, administrative problems were reported. In most cases the underlying, original name could be identified. The document experts found no evidence of a deliberate attempt to conceal the alterations. A search of the NBSS database for the underlying and superimposed names revealed that only 1 of the women whose name had been deleted or superimpsed died of breast cancer. She was in the mammography arm. The authors'' thorough review of ways in which the randomization could have been subverted failed to uncover credible evidence of it. They conclude that even if there had been acts of subversion, they could only have been few in number and, given that there was only 1 death from breast cancer in the group reviewed, the alterations could have had only a trivial effect on the study findings as reported in 1992.     

产前超声在中孕期胎儿严重先天性心脏病筛查中的应用

目的:探究产前超声检查在中孕期胎儿严重先天性心脏病(CHD)筛查中的应用。方法:选择2012年1月至2014年1月在我院妇产科进行产前常规超声检查的孕妇12076例,年龄22-41岁,平均(28.6±8.3)岁,孕周20-36周,平均(25.2±6.7)周。将符合纳入排除标准的孕妇8953例作为研究对象,其中初产妇6023例,经产妇2930例。对纳入研究的孕妇行彩色多普勒超声检查,并对妊娠结局进行追踪,将确诊情况与筛查结果进行比较分析。结果:产前彩色多普勒超声诊断出胎儿CHD38例,经尸检或新生儿彩色多普勒超声检查均确诊为CHD,对胎儿期未筛查出CHD的孕妇进行新生儿彩色多普勒超声检查,确诊4例,产前超声检查胎儿CHD检出率为90.48%(38/42),检出准确率100%(38/38)。结论:彩色多普勒超声筛查孕中期胎儿CHD,灵敏度和特异性高,安全无创伤,操作简便快速,值得推广为产前筛查的首选方法。     

Estimating key parameters in periodic breast cancer screening—Application to the Canadian National Breast Screening Study data

Problem statement: Breast cancer screening in women of younger age has been controversial. The screening sensitivities, transition probabilities and sojourn time distributions are estimated for females aged 40–49 years and 50–59 years separately, using the Canadian National Breast Screening Study (CNBSS) data. The purpose is to estimate the lead time distribution and the probability of not detecting the cancer early. Approach: Within the 40–49-year-old and 50–59-year-old cohorts separately, the age-independent statistical model was applied. Bayesian estimators along with 95% highest probability density (HPD) credible intervals (CI) were calculated. Bayesian hypothesis testing was used to compare the parameter estimates of the two cohorts. The lead time density was also estimated for both the 40–49 and 50–59-year-old cohorts. Results: The screening sensitivity, transition probability of the disease, and mean sojourn time were all found to increase with age. For the 40–49-year-old and 50–59-year-old cohorts, the posterior mean sensitivities were 0.70 (95% HPD-CI: 0.46, 0.93) and 0.77 (0.61, 0.93), respectively. The posterior mean transition probabilities were 0.0023 (0.0018, 0.0027) and 0.0031 (0.0024, 0.0038), while the posterior mean sojourn times were 2.55 (1.56, 4.26) years and 3.15 (2.12, 4.96) years. Bayes factors for the ratio of posterior probabilities that the respective parameter was larger vs. smaller in the 50–59-year-old cohort were estimated to be 2.09, 40.8 and 3.0 for the sensitivity, transition probability, and mean sojourn time, respectively. All three Bayes factors were larger than two, indicating greater than 2:1 odds in favor of the hypothesis that each of these parameters was greater in the 50–59-year-old cohort. The estimated mean lead times were 0.83 years and 0.96 years if the two cohorts were screened annually. Conclusions: The increase in sensitivity corresponds to an increase in the mean sojourn time. Breast cancer in younger women is more difficult to detect by screening tests and is more aggressive than breast cancer in older women. Women aged 50–59 tend to benefit more from screening compared with women aged 40–49.     

Effect of Calcifications on Breast Ultrasound Shear Wave Elastography: An Investigational Study

PurposeTo investigate the effects of macrocalcifications and clustered microcalcifications associated with benign breast masses on shear wave elastography (SWE).MethodsSuperSonic Imagine (SSI) and comb-push ultrasound shear elastography (CUSE) were performed on three sets of phantoms to investigate how calcifications of different sizes and distributions influence measured elasticity. To demonstrate the effect in vivo, three female patients with benign breast masses associated with mammographically-identified calcifications were evaluated by CUSE.ResultsApparent maximum elasticity (E_max) estimates resulting from individual macrocalcifications (with diameters of 2mm, 3mm, 5mm, 6mm, 9mm, 11mm, and 15mm) showed values over 50 kPa for all cases, which represents more than 100% increase over background (~21kPa). We considered a 2cm-diameter circular region of interest for all phantom experiments. Mean elasticity (E_mean) values varied from 26 kPa to 73 kPa, depending on the macrocalcification size. Highly dense clusters of microcalcifications showed higher E_max values than clusters of microcalcification with low concentrations, but the difference in E_mean values was not significant.ConclusionsOur results demonstrate that the presence of large isolated macrocalcifications and highly concentrated clusters of microcalcifications can introduce areas with apparent high elasticity in SWE. Considering that benign breast masses normally have significantly lower elasticity values than malignant tumors, such areas with high elasticity appearing due to presence of calcification in benign breast masses may lead to misdiagnosis.     

乳腺肿瘤超声图像形态特征参数分析

乳腺肿瘤超声图像的形态特征对判别肿瘤的良恶性具有重要的价值,在前人工作的基础上本文对形状因子,纵横比,成角分叶等几个形态特征参数进行详细的分析与比较,在一定程度上提高了相应参数的特异性和敏感度,将这些性能较好的参数与其他一些检测手段相结合,对于建立性能较好的乳腺癌计算机辅助识别系统有积极的意义。     

转基因玉米种子快速筛查方法研究与应用

转基因种子快速筛查技术研究与应用对于加强农业转基因生物安全管理至关重要。将DNA热碱提取法和复合荧光PCR技术相结合,建立起玉米种子转基因成分快速筛查方法。结果显示,该方法不仅能保证检测的准确性和灵敏性,而且还大大降低假阳性发生率,提高转基因筛查的效率,适合大批量样品的快速检测。     

四维彩超技术在筛查胎儿先天性心脏病的应用价值分析

目的:探讨四维彩超技术在筛查胎儿先天性心脏病的应用价值。方法:择取我院2012年3月至2014年3月收治的行产前筛查的300例产妇为研究对象,采用四维彩色多普勒超声择取心脏三血管、四腔观、肺动脉分叉、上下腔静脉回流、动脉导管弓、主动脉弓等常规切面,予以胎心各腔血流及胎心率等多项检测,对胎儿是否存在先心病进行综合诊断,并综合胎儿大体解剖状况,与病理诊断及二维超声检查结果进行对比。结果:四维彩超检出率为6.67%,正确率为90.00%;二维超声检出率为6.00%,正确率为83.33%,两组比较差异具有统计学意义(P0.05)。结论:四维彩超技术在筛查胎儿先天性心脏病中具有至关重要的应用价值,有助于指导胎儿先天性心脏病早期治疗,保证患儿预后,值得临床借鉴。     

生物技术领域中超声波的应用

超声波具有穿透力强、方向性好的特点,在很多领域有着广泛的应用前景。超声波应用于生物技术领域,具有成本低、操作简单、生物效应明显、污染小或无污染等优点。本文概述了超声波生物学效应的产生机制,及其在植物无基质培养、生物活性物质的提取、固定化酶活性的提高及基因转导等生物技术领域中的应用及前景。     

Risk-Specific Optimal Cancer Screening Schedules: An Application to Breast Cancer Early Detection

The optimal schedules for breast cancer screening in terms of examination frequency and ages at examination are of practical interest. A decision-theoretic approach is explored to search for optimal cancer screening programs which should achieve maximum survival benefit while balancing the associated cost to the health care system. We propose a class of utility functions that account for costs associated with screening examinations and value of survival benefit under a non-stable disease model. We consider two different optimization criteria: optimize the number of screening examinations with equal screening intervals between exams but without a prefixed total cost; and optimize the ages at which screening should be given for a fixed total cost. We show that an optimal solution exists under each of the two frameworks. The proposed methods may consider women at different levels of risk for breast cancer so that the optimal screening strategies will be tailored according to a woman’s risk of developing the disease. Results of a numerical study are presented and the proposed models are illustrated with various data inputs. We also use the data inputs from the Health Insurance Plan of New York (HIP) and Canadian National Breast Screening Study (CNBSS) to illustrate the proposed models and to compare the utility values between the optimal schedules and the actual schedules in the HIP and CNBSS trials. Here, the utility is defined as the difference in cure rates between cases found at screening examinations and cases found between screening examinations while accounting for the cost of examinations, under a given screening schedule.     

Observed and Predicted Risk of Breast Cancer Death in Randomized Trials on Breast Cancer Screening

BackgroundThe role of breast screening in breast cancer mortality declines is debated. Screening impacts cancer mortality through decreasing the number of advanced cancers with poor diagnosis, while cancer treatment works through decreasing the case-fatality rate. Hence, reductions in cancer death rates thanks to screening should directly reflect reductions in advanced cancer rates. We verified whether in breast screening trials, the observed reductions in the risk of breast cancer death could be predicted from reductions of advanced breast cancer rates.ResultsThe observed and predicted RR of breast cancer death were 0.72 (0.56–0.94) and 0.98 (0.77–1.24) in the HIP trial, and 0.79 (0.78–1.01) and 0.90 (0.80–1.01) in the Age trial. In the TCT, the observed RR was 0.73 (0.62–0.87), while the predicted RR was 0.89 (0.75–1.05) if overdiagnosis was assumed to be negligible and 0.83 (0.70–0.97) if extra cancers were excluded.ConclusionsIn breast screening trials, factors other than screening have contributed to reductions in the risk of breast cancer death most probably by reducing the fatality of advanced cancers in screening groups. These factors were the better management of breast cancer patients and the underreporting of breast cancer as the underlying cause of death. Breast screening trials should publish stage-specific fatalities observed in each group.     

Alternative Ultrasound Gel for a Sustainable Ultrasound Program: Application of Human Centered Design

This paper describes design of a low cost, ultrasound gel from local products applying aspects of Human Centered Design methodology. A multidisciplinary team worked with clinicians who use ultrasound where commercial gel is cost prohibitive and scarce. The team followed the format outlined in the Ideo Took Kit. Research began by defining the challenge "how to create locally available alternative ultrasound gel for a low-resourced environment? The "End-Users," were identified as clinicians who use ultrasound in Democratic Republic of the Congo and Ethiopia. An expert group was identified and queried for possible alternatives to commercial gel. Responses included shampoo, oils, water and cornstarch. Cornstarch, while a reasonable solution, was either not available or too expensive. We then sought deeper knowledge of locally sources materials from local experts, market vendors, to develop a similar product. Suggested solutions gleaned from these interviews were collected and used to create ultrasound gel accounting for cost, image quality, manufacturing capability. Initial prototypes used cassava root flour from Great Lakes Region (DRC, Rwanda, Uganda, Tanzania) and West Africa, and bula from Ethiopia. Prototypes were tested in the field and resulting images evaluated by our user group. A final prototype was then selected. Cassava and bula at a 32 part water, 8 part flour and 4 part salt, heated, mixed then cooled was the product design of choice.