剪切波弹性成像技术联合多参数评估肝硬化患者食管静脉曲张价值研究*

目的 探讨应用剪切波弹性成像(SWE)技术联合多参数评估肝硬化患者并发食管静脉曲张(EV)的价值。方法 2018年3月～2021年3月我院收治的肝硬化患者89例,接受胃镜检查,了解EV发生情况,采用SWE技术检测脾脏杨氏模量最大值(Emax)和杨氏模量平均值(Emean),使用彩色多普勒超声检测肝脏门静脉直径(PVD)、脾脏厚径(ST)、脾脏长径(SD)和脾静脉直径(SVD),应用受试者工作特征曲线下面积(AUC)分析各参数诊断肝硬化患者并发EV的效能。结果 经胃镜检查发现,本组89例肝硬化患者并发EV者53例;EV组在Child-Pugh分级、白蛋白、凝血酶原时间国际标准化比值、血小板计数和有腹水的比率等方面与非EV组比,均存在显著性差异(P<0.05);EV组Emax和Emean分别为(55.9±10.5)kPa和(38.9±9.2)kPa,显著大于非EV组【分别为(45.2±7.3)kPa和(29.3±6.7)kPa,P<0.05】,PVD、ST、SD和SVD分别为(13.6±2.1)mm、(48.0±9.4)mm、(149.1±27.1)mm和(10.1±1.9)mm,均显著大于非EV组【分别为(11.5±1.8)mm、(36.9±8.7)mm、(119.8±24.9)mm和(7.8±1.7)mm,P<0.05】;分别以Emax、Emean、PVD、ST、SD和SVD为53.2 kPa、33.6 kPa、11.9 mm、43.8 mm、136.5 mm和8.9 mm为截断点,其诊断肝硬化并发EV的AUC分别为0.84、0.83、0.73、0.80、0.67和0.82,诊断的敏感度和特异度分别为66.0%和88.9%、75.5%和77.8%、79.3%和61.1%、77.4%和72.2%、58.5%和69.4%、77.4%和80.6%。结论 应用SWE技术测量脾脏Emax和Emean可用于肝硬化患者并发EV的诊断,对帮助判断病情,及时予以预防处理。     

Prediction of pancreatic fistula after pancreatectomy by virtual touch tissue imaging and quantification (VTIQ) technology

ObjectivesThe aim of this study was to quantitatively evaluate the stiffness of pancreatic parenchyma and solid focal pancreatic lesions (FPLs) by virtual touch tissue imaging and quantification (VTIQ) technique and to investigate the potential usefulness of VTIQ method in the prediction of post-operative pancreatic fistula (POPF) after pancreatectomy.MethodsIn this prospective study, patients who scheduled to undergo pancreatectomy were initially enrolled and received VTIQ assessment within one week before surgery. VTIQ elastography (Siemens ACUSON Sequoia, 5C-1 transducer) was used to measure the shear wave velocity (SWV) value of FPLs and the body part pancreatic parenchyma. The palpation stiffness of pancreas was qualitatively evaluated during operation by surgeons. POPF was finally diagnosed and graded through a three-weeks post-operative follow-up according to international study group of pancreatic fistula (ISGPF). SWV values were compared between POPF positive and negative group. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic efficacy of SWV value in predicting POPF.ResultsFrom December 2020 to June 2021, 44 patients were finally enrolled in this study, among which, 26 patients were identified to develop POPF after pancreatectomy. The SWV value of pancreatic parenchyma in POPF positive group was significantly lower than that in POPF negative group (P = 0.001). However, there was no significant difference in palpation stiffness between the two groups (P = 0.124). Besides, neither the SWV value of FPL nor the SWV ratio between FPL to surrounding pancreatic parenchyma differ significantly between POPF positive and negative group (P > 0.05). Taking SWV value of pancreatic parenchyma >1.10 m/s as a cut-off value for predicting POPF, area under the receiver operating characteristic curve (AUROC) was 0.864 with 72.2% sensitivity, 92.3% specificity, 86.7% positive predictive value (PPV) and 82.8% negative predictive value (NPV), respectively.ConclusionsVTIQ technique might be a potential non-invasive imaging method to predict POPF before pancreatectomy in future clinical practice.     

An initial trial of quantitative evaluation of autoimmune pancreatitis using shear wave elastography and shear wave dispersion in transabdominal ultrasound

Background/ObjectivesWe aimed to examine therapeutic efficacy and prognosis prediction of autoimmune pancreatitis (AIP) using shear wave elastography (SWE) and shear wave dispersion (SWD) in transabdominal ultrasound (US).MethodsThe subjects were 23 patients with diffuse type 1 AIP who underwent SWE and SWD, and 34 controls with a normal pancreas. Elasticity and dispersion were defined as the pancreatic elastic modulus (PEM) and dispersion slope, respectively. PEM and dispersion slope were compared between AIP and control cases, and the short-term therapeutic effect and long-term prognosis were examined.ResultsPEM (30.9 vs. 6.6 kPa, P < 0.001) and dispersion slope (15.3 vs. 13.0 (m/sec)/kHz, P = 0.011) were significantly higher in AIP cases than in controls. Among the 17 AIP patients followed-up in two weeks after treatment, these parameters were 12.7 kPa and 10.5 (m/sec)/kHz with median decrease rate of 37.2% and 32.8%, respectively, which were significantly higher than the change in the size of pancreatic parenchyma (14.4%, P = 0.026). Fourteen of these subjects were followed up for >12 months, during which 2 had relapse; diabetes improved in 5 and worsened in 2; in 60% of cases, the pancreatic parenchyma was atrophied. The % change in PEM after two weeks was tended to be higher in non-atrophy cases.ConclusionSWE and SWD measurement in US may be useful for quantitative assessment of AIP and evaluation of short-term treatment efficacy.     

利用剪切波弹性成像监控肝脏温度变化的实验研究

目的 进行利用剪切波弹性成像（Shear wave elastography,SWE）监控肝脏温度变化的实验研究,以探讨SEW是否可用于肝肿瘤光热消融治疗时正常肝脏组织温度值的精准评价。方法 以水浴法对新鲜离体猪肝进行加热。利用SWE结合肝组织病理切片分析肝组织自35℃升温至85℃时的组织硬度值;利用SWE结合肝组织病理切片分析肝组织维持一定温度10分钟后组织硬度值的变化。结果 在55℃～85℃时,肝组织硬度值随温度增高而增加,各温度组间比较有统计学差异（P<0.05）,肝组织病理切片有明显变化。当肝组织温度为55-80时,肝组织维持温度值10分钟前后肝组织硬度值比较均无统计学差异（P>0.05）,肝组织病理切片有明显变化。结论 肝组织温度值为55℃～80℃时,可以通过SWE测量肝组织硬度值这一参数精确评价光热治疗时正常肝组织的温度值变化。     

剪切波弹性成像评估腹膜透析患者腹膜硬化程度的应用价值

目的 应用剪切波弹性成像（SWE）评估腹膜透析患者腹膜硬化程度,探讨其临床应用价值。方法 选取我院行持续非卧床腹膜透析（CAPD）患者168例,根据不同腹膜透析时间分为≤3年组71例、3～11年组78例、≥11年组19例,应用常规超声观测各组肠壁、腹膜厚度及回声、有无钙化等,并对其进行超声评分;应用SWE测量肠壁、腹膜杨氏模量平均值（Emean）,比较各组超声评分、SWE参数的差异;分析超声评分、SWE参数与透析时间的相关性。结果 ≤3年组、3～11年组、≥11年组超声评分分别为0(0,0)分、4.9(3.5,7.4)分、7.5(5.7,8.9)分;≤3年组、3～11年组、≥11年组肠壁Emean分别为1.0(0,2.0)kPa、9.9(6.3,14.1)kPa、11.9(6.5,18.6)kPa,腹膜Emean分别为2.0(0,3.0)kPa、11.4(6.5,20.9)kPa、20.3(11.0,30.4)kPa;3～11年组、≥11年组超声评分及肠壁、腹膜Emean均高于≤3年组,差异均有统计学意义（均P<0.01）;3～11年组与≥11年组上述参数比较差异均无统计学意义。...     

The use of external mesh reinforcement to reduce intimal hyperplasia and preserve the structure of human saphenous veins

The saphenous vein is the conduit of choice in bypass graft procedures. Haemodynamic factors play a major role in the development of intimal hyperplasia (IH), and subsequent bypass failure. To evaluate the potential protective effect of external reinforcement on such a failure, we developed an ex vivo model for the perfusion of segments of human saphenous veins under arterial shear stress. In veins submitted to pulsatile high pressure (mean pressure at 100 mmHg) for 3 or 7 days, the use of an external macroporous polyester mesh 1) prevented the dilatation of the vessel, 2) decreased the development of IH, 3) reduced the apoptosis of smooth muscle cells, and the subsequent fibrosis of the media layer, 4) prevented the remodelling of extracellular matrix through the up-regulation of matrix metalloproteinases (MMP-2, MMP-9) and plasminogen activator type I. The data show that, in an experimental ex vivo setting, an external scaffold decreases IH and maintains the integrity of veins exposed to arterial pressure, via increase in shear stress and decrease wall tension, that likely contribute to trigger selective molecular and cellular changes.     

管径比对全阻塞动脉旁路移植流场影响的数值研究

目的 研究管径比对全阻塞动脉旁路移植流场的影响,为指导动脉旁路移植手术,减少术后再狭窄提供理论依据。方法 采用数值方法研究5种不同移植管与主血管的管径比对全阻塞情况下动脉旁路移植流场的影响,分析速度、二次流、壁面切应力和壁面切应力梯度等血流动力学参数的分布及其随管径比增大的改变。同时,为表明本文所采用模型的合理性,针对目前常使用的两类模型,比较在管径比1.0情况下全阻塞完整模型（Model A）、全阻塞局部模型（Model B）和75％狭窄完整模型（Model C）之间的血流动力学差异。结果 Model A和Model C的血流动力学特性是完全不同的;移植管顶部截面内的速度分布对下游吻合处的主血管底部壁面切应力的影响是显著的,最大相差达79％。大管径比时,主血管底部的壁面低切应力区较大,但壁面切应力分布均匀,壁面切应力梯度较小。而小管径比时,主血管底部的壁面低切应力区较小,但壁面切应力梯度较大。结论 采用整体模型单独研究全阻塞情况下的管径比对流场的影响是有必要的。管径比对全阻塞动脉旁路移植的流场具有显著影响,采用大管径比进行动脉旁路移植将有助于缓解吻合口处由于再狭窄而产生的阻塞。     

流体剪切应力对晚期内皮祖细胞生物学功能的影响

目的 研究流体剪切应力处理对晚期内皮祖细胞（endothelial progenitor cells,EPCs）体外及体内生物学功能的影响。 方法 密度梯度离心法分离大鼠骨髓单核细胞,应用EGM-2MV进行体外培养。以3~4代的EPCs,即晚期EPCs为靶细胞,对其施以1.2 Pa剪切应力处理。采用EdU标记技术、黏附能力测定实验、改良的Boyden小室、Annexin V/PI、β 半乳糖苷酶检测法、Matrigel法、荧光定量RT PCR等方法分别检测剪切应力对晚期EPCs增殖、黏附、迁移、凋亡、衰老、体外成血管及VEGF mRNA表达等生物学功能的影响。应用大鼠颈动脉损伤模型及细胞原位移植等实验手段检测剪切应力预处理对晚期EPCs修复受损内皮的影响。结果1.2 Pa剪切应力处理可不同程度提高晚期EPCs的增殖、黏附、迁移及成血管能力（P＜0.01）,上调VEGF的基因表达,抑制晚期EPCs的衰老及凋亡（P＜0.01）;移植经剪切应力预处理的晚期EPCs可加速损伤内皮的修复,减缓内膜的增生。结论 流体剪切应力可改善晚期EPCs的功能活性,提高晚期EPCs修复损伤血管内皮的能力, 这为EPCs的临床应用及剪切应力介导的细胞疗法提供了实验依据。     

Effects of surface treatment and artificial aging on the shear bond strength of orthodontic brackets bonded to four different provisional restorations

Objective:To evaluate the combined effects of material type, surface treatment, and thermocycling on the bond strength of orthodontic brackets to materials used for the fabrication of provisional crowns.Materials and Methods:Four materials were included in this study (ProTemp, Trim Plus, Trim II, and Superpont C+B). Sixty cylindrical specimens (1 × 3 cm) were prepared from each material and equally divided into three groups. The first group was ground with silica carbide paper, the second was polished with pumice, and the last group was sandblasted with 50-µm aluminum oxide particles. Stainless-steel maxillary central incisor brackets (Victory Series, 3M) were bonded to the provisional material specimens with Transbond XT light-cured composite resin, and half of the specimens from each group were thermocycled 500 times in 5°C and 55°C water baths. Then the brackets were debonded with shear testing, and the results were statistically analyzed by three-way analysis of variance and Tukey''s multiple-comparison tests at α  =  0.05. Adhesive Remnant Index (ARI) was also identified.Results:Before and after thermocycling, ProTemp materials showed the highest shear bond strength with orthodontic brackets (10.3 and 13.1 MPa, respectively). The statistical analysis indicated an interaction among the three independent variables (P < .05) and statistically significant differences in bond strength among provisional materials (P < .001), surface treatments (P < .001), and thermocycling (P < .05). According to the ARI, most groups demonstrated adhesive failure.Conclusions:The provisional material type, surface treatment, and artificial aging have a significant effect on bond strength. Sandblasting treatment exerts a beneficial effect on shear bond strength.