A neuroglia-based interpretation of glaucomatous neuroretinal rim thinning in the optic nerve head

Neuroretinal rim thinning (NRR) is a characteristic glaucomatous optic disc change. However, the precise mechanism of the rim thinning has not been completely elucidated. This review focuses on the structural role of the glioarchitecture in the formation of the glaucomatous NRR thinning. The NRR is a glia-framed structure, with honeycomb geometry and mechanically reinforced astrocyte processes along the transverse plane. When neural damage selectively involves the neuron and spares the glia, the gross structure of the tissue is preserved. The disorganization and loss of the glioarchitecture are the two hallmarks of optic nerve head (ONH) remodeling in glaucoma that leads to the thinning of NRR tissue upon axonal loss. This is in contrast to most non-glaucomatous optic neuropathies with optic disc pallor where hypertrophy of the glioarchitecture is associated with the seemingly absent optic disc cupping. Arteritic anterior ischemic optic neuropathy is an exception where pan-necrosis of ONH tissue leads to NRR thinning. Milder ischemia indicates selective neuronal loss that spares glia in non-arteritic anterior ischemic optic neuropathy. The biological reason is the heterogeneous glial response determined by the site, type, and severity of the injury. The neuroglial interpretation explains how the cellular changes underlie the clinical findings. Updated understandings on glial responses illustrate the mechanical, microenvironmental, and microglial modulation of activated astrocytes in glaucoma. Findings relevant to the possible mechanism of the astrocyte death in advanced glaucoma are also emerging. Ultimately, a better understanding of glaucomatous glial response may lead to glia-targeting neuroprotection in the future.     

实时剪切波弹性成像评价先天性肌性斜颈胸锁乳突肌

目的 应用实时剪切波弹性成像（SWE）技术评价先天性肌性斜颈（CMT）患儿胸锁乳突肌（SCM）。方法 对130例初诊CMT患儿进行二维超声检查,根据二维超声表现确定其二维分型（Ⅰ~Ⅳ型）,采用SWE测量患侧、健侧SCM弹性模量平均值（E_mean）;对患侧二维超声表现分型与E_mean进行相关性分析;运用ROC曲线计算各型的E_mean截断值。结果 CMT患儿各二维超声表现分型健侧与患侧SCM的E_mean差异有统计学意义（P<0.05）。各二维超声表现分型与患侧E_mean呈正相关（r_s=0.76,P<0.05）。利用ROC曲线获得Ⅰ~Ⅳ型E_mean截断值分别为15.35 kPa、29.60 kPa、38.05 kPa及47.80 kPa。结论 SWE技术可客观量化显示SCM硬度,评估CMT患儿胸锁乳突肌纤维化严重程度,具有较高临床价值。     

Assessment of Structural Heterogeneity and Viscosity in the Cervix Using Shear Wave Elasticity Imaging: Initial Results from a Rhesus Macaque Model

Shear wave elasticity imaging has shown promise in evaluation of the pregnant cervix. Changes in shear wave group velocity have been attributed exclusively to changes in stiffness. This assumes homogeneity within the region of interest and purely elastic tissue behavior. However, the cervix is structurally/microstructurally heterogeneous and viscoelastic. We therefore developed strategies to investigate these complex tissue properties. Shear wave elasticity imaging was performed ex vivo on 14 unripened and 13 misoprostol-ripened cervix specimens from rhesus macaques. After tests of significant and uniform shear wave displacement, as well as reliability of estimates, group velocity decreased significantly from the distal (vaginal) to proximal (uterine) end of unripened, but not ripened, specimens. Viscosity was quantified by the slope of the phase velocity versus frequency. Dispersion was observed in both groups (median: 5.5 m/s/kHz, interquartile range: 1.5–12.0 m/s/kHz), also decreasing toward the proximal cervix. This work suggests that comprehensive assessment of complex tissues such as cervix requires consideration of structural heterogeneity and viscosity.     

Liver failure after hepatectomy: A risk assessment using the pre-hepatectomy shear wave elastography technique

ObjectiveTo determine the efficacy of liver stiffness (LS) measurements utilizing the Shear Wave Elastography (SWE) technique for predicting post-hepatectomy liver failure (PHLF) among patients with hepatocellular carcinoma (HCC).MethodsData from eighty consecutive patients who were undergoing hepatectomy for HCC were prospectively identified and evaluated with preoperative SWE. The SWE was measured with advanced ultrasound equipment (Philips EPIQ7; Philips Healthcare, Seattle, WA, USA). PHLF classification was defined according to the International Study Group of Liver Surgery Recommendations (ISGLS).ResultsSWE was successfully performed in 77 patients. According to the ISGLS criteria, PHLF occurred in 35.1% of patients (27 patients), including 2/25 patients with Grade A/B, respectively. Elevated SWE values (P = 0.002) and histological cirrhosis (P = 0.003) were independent predictors of PHLF according to the multivariate analysis. Patients with SWE values higher than or equal to 6.9 kPa were identified at higher risk of PHLF (area under the curve: 0.843, sensitivity: 77.8% and specificity: 78.0%). Postoperative dynamic course of the median the Model For End-stage Liver Disease (MELD) score showed irregular changes among patients with an SWE >6.9 kPa. Patients with an SWE <6.9 kPa, postoperative dynamic course of the median MELD score gradually decreased.ConclusionLS measured with SWE is a valid and reliable method for the prediction of PHLF grade A/B among patients with HCC. SWE could become a routine examination for the preoperative evaluation of PHLF.     

A new qualitative pattern classification of shear wave elastograghy for solid breast mass evaluation

ObjectivesTo examine the efficacy of qualitative shear wave elastography (SWE) in the classification and evaluation of solid breast masses, and to compare this method with conventional ultrasonograghy (US), quantitative SWE parameters and qualitative SWE classification proposed before.MethodsFrom April 2015 to March 2016, 314 consecutive females with 325 breast masses who decided to undergo core needle biopsy and/or surgical biopsy were enrolled. Conventional US and SWE were previously performed in all enrolled subjects. Each mass was classified by two different qualitative classifications. One was established in our study, herein named the Qual1. Qual1 could classify the SWE images into five color patterns by the visual evaluations: Color pattern 1 (homogeneous pattern); Color pattern 2 (comparative homogeneous pattern); Color pattern 3 (irregularly heterogeneous pattern); Color pattern 4 (intralesional echo pattern); and Color pattern 5 (the stiff rim sign pattern). The second qualitative classification was named Qual2 here, and included a four-color overlay pattern classification (Tozaki and Fukuma, Acta Radiologica, 2011). The Breast Imaging Reporting and Data System (BI-RADS) assessment and quantitative SWE parameters were recorded. Diagnostic performances of conventional US, SWE parameters, and combinations of US and SWE parameters were compared.ResultsWith pathological results as the gold standard, of the 325 examined breast masses, 139 (42.77%) samples were malignant and 186 (57.23%) were benign. The Qual1 showed a higher Az value than the Qual2 and quantitative SWE parameters (all P < 0.05). When applying Qual1 = Color pattern 1 for downgrading and Qual1 = Color pattern 5 for upgrading the BI-RADS categories, we obtained the highest Az value (0.951), and achieved a significantly higher specificity (86.56%, P = 0.002) than that of the US (81.18%) with the same sensitivity (94.96%).ConclusionsThe qualitative classification proposed in this study may be representative of SWE parameters and has potential to be relevant assistance in breast mass diagnoses.     

Usefulness of noninvasive methods including assessment of liver stiffness by 2-dimensional shear wave elastography for predicting esophageal varices

BackgroundThe aim of this study was to predict the presence of esophageal varices (EVs) by noninvasive tools combined with 2-dimensional shear wave elastography (2D-SWE), and to compare the diagnostic capabilities of 2D-SWE with those of transient elastography (TE).MethodsBetween January 2015 and December 2017, 289 patients with compensated advanced chronic liver disease (cACLD) who underwent consecutive 2D-SWE and EGD were enrolled. Capabilities for predicting the presence of EVs of 2D-SWE and models combining 2D-SWE with other noninvasive tools (modified LS-spleen-diameter-to-platelet-ratio score [mLSPS], platelet-spleen ratio score) were compared. A subgroup analysis was performed on 177 patients who also underwent simultaneous TE.ResultsThe area under receiver operating characteristics (AUROCs) for detecting EVs for 2D-SWE alone vs. mLSPS, which included 2D-SWE, were 0.757 (95% confidence interval [CI], 0.701–0.810) and 0.813 (95% CI, 0.763–.857), respectively. The AUROCs for predicting varices needing treatment (VNT) for 2D-SWE and mLSPS were 0.712 (95% CI, 0.621–0.738) and 0.834 (95% CI, 0.785–0.875), respectively. For the 195 patients who underwent simultaneous TE and 2D-SWE, no differences in diagnostic performance were observed.ConclusionsThe diagnostic performance of 2D-SWE is similar to that of TE for predicting the presence of EVs. The mLSPS, which includes 2D-SWE, seemed to be useful for predicting EVs.     

实时剪切波弹性成像对正常儿童肝脏硬度的研究

目的 探讨实时剪切波弹性成像（SWE）技术在检测健康儿童肝组织硬度中的应用价值。方法 对243名正常健康儿童行SWE检查,测量肝脏硬度值（LSM）,比较不同性别及肝段间LSM差异。根据年龄将243名儿童分为学龄前期组、学龄期组、青春期组,比较3组间LSM差异。对不同操作者测量值行一致性分析。结果 正常儿童LSM均值为（4.21±0.70）kPa,95%可信区间为（4.11,4.31）kPa;肝S5段的取样成功率高于S4段[（100%（243/243） vs 79.83%（194/243）],S5段LSM平均值[（4.07±0.71）kPa]低于肝S4段[（4.49±0.95）kPa],差异有统计学意义（P<0.01）;LSM随年龄增长有增高趋势,男童LSM较女童稍高,差异均无统计学意义（P均>0.05）。不同操作者测值一致性非常好,组内相关系数为0.92。结论 SWE可客观、定量评估儿童肝脏硬度。     

Evaluation of Non-alcoholic Fatty Liver Disease Using Acoustic Radiation Force Impulse Imaging Elastography in Rat Models

The aim of this study is to evaluate the utility of acoustic radiation force impulse (ARFI) elastography for assessing hepatic fibrosis stage and non-alcoholic fatty liver disease (NAFLD) severity, as well as the relationship among hepatic histologic changes using shear wave velocity (SWV). Animal models with various degrees of NAFLD were established in 110 rats. The right liver lobe was processed and embedded in a fabricated gelatin solution (porcine skin). Liver mechanics were measured using SWV induced by acoustic radiation force. Among the histologic findings, liver elasticity could be used to differentiate normal rats from rats with simple steatosis (SS) as well as distinguish SS from non-alcoholic steatohepatitis (NASH), with areas under the receiver operating characteristic curves (AUROC) of 0.963 (95% confidence interval = 0.871–0.973) and 0.882 (95% confidence interval = 0.807–0.956), respectively. For NAFLD rats, the diagnostic performance of ARFI elastography in predicting significant fibrosis (F ≥ 2) had an AUROC of 0.963. For evaluating steatosis severity, we found a progressive increase in ARFI velocity proportional to steatotic severity in NAFLD rat models, but we observed no significant differences for steatotic severity after excluding the rats with fibrosis. ARFI elastography may be used to differentiate among degrees of severity of NAFLD and hepatic fibrotic stages in NAFLD rat models.     

等剪切场中剪切诱导血小板释放神经肽Y

采用剪切激活血小板的方法，利用特异性放射免疫分析显示大鼠富血小板血浆（ＰＲＰ）与富血小板组分（ＰＥＦ）分别含神经肽Ｙ（ＮＰＹ）免疫活性物质９２．５９±１０．０９μｇ／Ｌ与９７．０２±３１．１１μｇ／Ｌ，高于去血小板血浆（ＰＦＰ）（１．５２±１．３２μｇ／Ｌ），与贫血小板血浆（ＰＰＰ）（１．６６±１．６１μｇ／Ｌ）中的含量（Ｐ＜０．００１）。ＰＲＰ经剪切诱发血小板聚集后，ＰＦＰｓ（剪切后）中ＮＰＹ浓度升高到２．２５±１．３７μｇ／Ｌ（Ｐ＜０．０５），ＰＰＰ经剪切后ＮＰＹ浓度则降为１．２２±１．０７μｇ／Ｌ。结果表明大鼠血小板中含有大量ＮＰＹ，经剪切激活血小板使其聚集时，可以释放。剪切后ＰＲＰｓ与ＰＥＦｓ的ＮＰＹ浓度均升高，分别为１１２．４９±２３．０μｇ／Ｌ与１２１．９１±３１．２９μｇ／Ｌ，提示剪切促进血小板合成ＮＰＹ。