剪切波弹性成像鉴别乳腺影像报告和数据系统(BI-RADS)4类乳腺肿块

目的探讨剪切波弹性成像(SWE)鉴别乳腺影像报告和数据系统(BI-RADS)4类乳腺肿块的价值。方法回顾性分析经术后病理证实的96个BI-RADS 4类乳腺肿块,比较良性(良性组,n=43)及恶性肿块(恶性组,n=53)剪切波参数,包括弹性最大值(SWE max)、最小值(SWE min)和平均值(SWE mean);以受试者工作特征(ROC)曲线确定SWE max、SWE min及SWE mean的截断值,比较其ROC曲线下面积(AUC)、敏感度、特异度和准确率,评价并比较SWE对BI-RADS 4a、4b及4c亚分类的诊断准确率。结果良性组SWE max和SWE mean均低于恶性组(P均<0.01),组间SWE min差异无统计学意义(P>0.05);SWE max、SWE mean的AUC分别为0.86、0.83,均高于SWE min的AUC(0.59,P均<0.01);SWE max诊断敏感度、特异度和准确率分别为96.23%、81.40%和89.58%,SWE mean分别为94.34%、76.74%和86.46%,均明显高于SWE min的34.00%、37.21%和35.42%(P均<0.01);SWE max和SWE mean的AUC及其诊断BI-RADS 4类乳腺良恶性肿块的敏感度、特异度、准确率差异均无统计学意义(P均>0.05)。SWE max和SWE mean对BI-RADS 4a、4b及4c乳腺肿块的诊断准确率明显高于SWE min(P<0.05)。结论BI-RADS 4类乳腺恶性肿块的SWE max和SWE mean均高于良性肿块。高频超声SWE可有效鉴别BI-RADS 4类乳腺良恶性肿块,SWE max和SWE mean的诊断效能优于SWE min。     

剪切波弹性成像技术定量评价亚临床性甲状腺功能减退症患者颈动脉弹性

目的 观察剪切波弹性成像（SWE）技术定量评价亚临床性甲状腺功能减退症（SCH）患者颈动脉弹性的价值,并与射频超声技术进行对比。方法 纳入84例SCH患者（观察组）及82名健康志愿者（对照组）,以射频超声技术获取双侧颈动脉内-中膜厚度（IMT）、膨胀系数（DC）、顺应系数（CC）、α系数、β系数及脉搏波传导速度（PWV）,以SWE技术测量平均、最大及最小弹性模量（ME_mean、ME_max、ME_min）,并比较各参数组间差异。采用线性回归评价各射频超声参数与ME_mean间相关性。绘制受试者工作特征（ROC）曲线,计算曲线下面积（AUC）,评价ME_mean诊断SCH患者动脉弹性改变的效能。结果 观察组DC及CC均明显低于对照组（P均<0.05）,α系数、β系数、PWV、ME_mean及ME_max均明显高于对照组（P均<0.05）。α系数、β系数、PWV与ME_mean均呈正相关（r=0.453、0.521、0.717,P均<0.05）。ME_mean预测SCH患者动脉弹性改变的AUC为0.822,敏感度为76.2%,特异度为63.8%。结论 SWE技术可用于评价SCH患者颈动脉弹性改变。     

Mild carbon monoxide poisoning impairs left ventricular diastolic function

Rationale:

Carbon monoxide (CO) poisoning is associated with direct cardiovascular toxicity. In mild CO poisoning in which cardiovascular life support is not required, the effects of CO on left and right ventricular functions are unknown in patients without cardiac failure.

Objectives:

Echocardiography was used to determine whether or not mild CO poisoning impairs ventricular function. Twenty otherwise healthy patients with CO poisoning and 20 age- and gender-matched controls were studied. Echocardiographic examinations were performed at the time of admission and 1 week after poisoning.

Results:

The impairment observed in the left and right ventricular diastolic function at the time of admission was greater than the impairment 1 week after poisoning. Mild CO poisoning did not have a significant effect on systolic function. Carboxyhemoglobin levels were positively correlated with left ventricular diastolic dysfunction, whereas the levels were not correlated with right ventricular diastolic function.

Conclusions:

In CO intoxication, the development of left and right ventricular diastolic dysfunction precedes systolic abnormality. Patients with mild CO poisoning do not manifest cardiovascular symptoms; however, it should be borne in mind that most of these patients have myocardial involvement.     

中老年血液透析病人心理弹性水平评价及其影响因素调查

目的:探讨中老年血液透析病人心理弹性水平及其影响因素。方法:选择我院收治的中老年血液透析病人200例,回顾性分析病人临床资料以获取基础信息,采取中文版心理弹性量表(CD-RISC)实施评价,统计心理弹性中高水平(≥50分)、心理弹性低水平(<50分)病人例数,借助多因素Logistic回归分析筛选中老年血液透析病人心理弹性水平的影响因素。结果:病人心理弹性评分为(62.16±2.53)分,中高水平病人158例,低水平病人42例;多因素Logistic回归分析显示,中老年血液透析病人心理弹性水平的影响因素有年龄≥60岁、透析龄<3年、初中及以下文化水平、健康教育缺失、自我效能低(<24分)、自我管理行为差(<40分)、屈服或回避应对、社会支持不足(<22分)(P<0.05)。结论:影响中老年血液透析病人心理弹性的因素复杂,提示应关注年龄≥60岁、透析龄<3年、初中及以下文化水平、健康教育缺失、自我效能低(<24分)、自我管理行为差(<40分)、屈服或回避应对、社会支持不足(<22分)的中老年血液透析病人,积极开展健康教育,加强护理指导,以改善心理性水平。     

An economic analysis of the demand for cannabis: some results from South Africa

Abstract

Background: The full legalization of cannabis is currently being deliberated in South Africa. We aim to better understand how the market operates by investigating how cannabis consumers respond to price changes and what factors are associated with the price that consumers pay.

Methods: We estimate the conditional price elasticity of demand using data on price, quantity, and quality from a cross-sectional survey of cannabis consumers across South Africa. We also investigate to what extent quality, quantity bought, income, and demographic variables influence the price paid for cannabis.

Results: The price of cannabis differs greatly by quality: medium-quality is almost double the price of low quality, while the price of high-quality cannabis is nine times that of low-quality cannabis. Depending on the model specification, we estimate that a 10% increase in the price per gram of cannabis is associated with an approximate 5–6% decrease in the quantity demanded. There is some evidence that the demand for medium- and high-quality cannabis is more price elastic than low quality. The price per gram is negatively associated with the quantity purchased and positively associated with income.

Conclusions: Price is a significant determinant of cannabis consumption. Increases in prices result in a decrease in quantity demanded.     

Acute decrease in the stiffness of resting muscle belly due to static stretching

The purpose of the study was to examine the acute effect of static stretching exercise on the resting stiffness of gastrocnemius muscle belly. Ten healthy young adults performed standing wall stretching in dorsiflexion for 1 min at a time and repeated five times. Before and after stretching, the shear modulus was measured in medial and lateral heads of the resting gastrocnemius muscle with ultrasound shear‐wave elastography. After the stretching, dorsiflexion range of motion (ROM) of the ankle joint increased (P < 0.01) by 3.9° and returned in 20 min. Immediately after stretching, shear modulus decreased (P < 0.01) by 14%, compared with before stretching across muscle heads. The decrease in shear modulus returned in 20 min after stretching. In the comparison group of 10 additional subjects, the standing intervention without stretching had no influence on these measures. There was a negative correlation between dorsiflexion ROM and shear modulus in either head before and after stretching. The results demonstrate the transient decreases in the stiffness of the resting gastrocnemius muscle belly and indicate that joint flexibility is greater in individuals with lower resting stiffness of the muscle belly.     

病变深度对乳腺良恶性病变超声弹性成像诊断效果的影响

目的 探讨占位性病变的深度对乳腺良、恶性病变超声弹性成像诊断效果的影响.方法 选取2010年2月～2014年10月进行超声弹性成像诊断的乳腺占位患者190例,按照能否获得满意弹性图像为标准分为满意组(170例)和不满意组(20例),收集两组患者病灶位置、病灶直径大小等资料,计算不同深度病灶的超声弹性成像的灵敏度、特异度、准确度,并进行统计学分析.结果 深度≤2.0 cm的病灶获得满意弹性成像的数量明显多于＞2.0 cm的病灶,二者图像满意率差异有统计学意义(P＜0.05);直径≤2.0 cm的病灶,图像满意组人数多于图像不满意组(P＜0.05);病灶深度＜0.5 cm时,准确度和特异度最高,＞1.5 cm时灵敏度降低.结论 病灶越浅、脂肪越少、乳房层越薄,越容易得到满意的弹性图像;同等深度时,病灶直径越大,对成像越有利,病灶病变深度会影响成像的准确度、特异度、灵敏度.     

Hard superconducting nitrides

Detailed study of the equation of state, elasticity, and hardness of selected superconducting transition-metal nitrides reveals interesting correlations among their physical properties. Both the bulk modulus and Vickers hardness are found to decrease with increasing zero-pressure volume in NbN, HfN, and ZrN. The computed elastic constants from first principles satisfy c11 > c12 > c44 for NbN, but c11 > c44 > c12 for HfN and ZrN, which are in good agreement with the neutron scattering data. The cubic delta-NbN superconducting phase possesses a bulk modulus of 348 GPa, comparable to that of cubic boron nitride, and a Vickers hardness of 20 GPa, which is close to sapphire. Theoretical calculations for NbN show that all elastic moduli increase monotonically with increasing pressure. These results suggest technological applications of such materials in extreme environments.     

Aortic elasticity and size in bicuspid aortic valve syndrome.

AIMS: To investigate the relation between aortic elastic properties and size in bicuspid aortic valves (BAVs). METHODS AND RESULTS: 127 BAV outpatients (121 males; age 23 +/- 10 years) with no or mild valvular impairment, were recruited with 114 control subjects comparable for age, gender, and body size. Aortic distensibility (DIS) and stiffness index (SI) were derived by M-mode evaluation of the aortic root together with blood pressure measured by cuff sphygmomanometer. BAVs vs. controls had increased aortic diameter (P < 0.0001), higher systolic (P = 0.02) and pulse (P = 0.04) pressures. DIS was lower in BAVs than in controls (4.71 +/- 3.67 vs. 7.44 +/- 3.94 10(-6) cm(2)dyne(-1), respectively; P < 0.0001) and SI was greater in BAVs (7.21 +/- 4.93 vs. 3.57 +/- 1.88, respectively; P < 0.0001). Definite impairment in aortic elasticity was present in 53 (42%) BAVs. Both DIS and SI were related (P < 0.0001) to aortic size in BAVs and controls. After adjusting for aortic size and blood pressure, the regression relations between SI and aortic diameter of BAVs were significantly different from controls (P = 0.0052). CONCLUSION: Abnormal aortic elasticity is a common finding in BAVs with no or mild aortic valve impairment. However, impaired aortic stiffness is not due to aortic dilation. Simple assessment of aortic size may thus fail to identify early abnormal load bearing characteristics of the aortic wall in BAVs.     

Value of shear wave elastography with maximal elasticity in differentiating benign and malignant solid focal liver lesions

BACKGROUNDIt is important to differentiate benign and malignant focal liver lesions (FLLs) accurately. Despite the wide use and acceptance of shear wave elastography (SWE), its value for assessing the elasticity of FLLs and differentiating benign and malignant FLLs is still investigational. Previous studies of SWE for FLLs used mean elasticity as the parameter to reflect the stiffness of FLLs. Considering the inhomogeneity of tumor stiffness, maximal elasticity (Emax) might be the suitable parameter to reflect the stiffness of FLLs and to differentiate malignant FLLs from benign ones.AIMTo explore the value of SWE with Emax in differential diagnosis of solid FLLs.METHODSWe included 104 solid FLLs in 95 patients and 50 healthy volunteers. All the subjects were examined using conventional ultrasound (US) and virtual touch tissue quantification(VTQ) imaging. A diagnosis of benign or malignant FLL was made using conventional US. Ten VTQ values were acquired after 10 consecutive measurements for each FLL and each normal liver, and the largest value was recorded as Emax.RESULTSThere were 56 cases of malignant FLLs and 48 cases of benign FLLs in this study. Emax of malignant FLLs (3.29 ± 0.88 m/s) was significantly higher than that of benign FLLs (1.30 ± 0.46 m/s, P < 0.01) and that of livers in healthy volunteers (1.15 ± 0.17 m/s, P < 0.01). The cut-off point of Emax was 1.945, and the area under the curve was 0.978. The sensitivity and specificity of Emax were 92.9% and 91.7%, respectively, higher (but not significantly) than those of conventional US (80.4% for sensitivity and 81.3% for specificity). Combined diagnosis of conventional US and Emax using parallel testing improved the sensitivity to 100% with specificity of 75%.CONCLUSIONSWE is a convenient and easy method to obtain accurate stiffness information of solid FLLs. Emax is useful for differential diagnosis of FLLs, especially in combination with conventional US.