The effect of paclitaxel plus carboplatin chemotherapy on subclinical cardiotoxicity in patients with non-small cell lung cancer: A speckle tracking echocardiography-based study

BackgroundAlthough chemotherapy-induced cardiotoxicity is an emerging problem, limited information is available on the effects of chemotherapy on left ventricular (LV) mechanical functions in patients with non-small cell lung cancer (NSCLC).ObjectiveWe aimed to explore chemotherapy-induced alterations in cardiac mechanical functions in patients with NSCLC using speckle tracking echocardiography (STE).MethodsSeventy-one patients with NSCLC and 34 age and sex matched control subjects were consecutively included. Based on their good performance status (Eastern Cooperative Oncology Group performance status), 39 patients were treated with paclitaxel plus carboplatin (PC) regimen and 32 patients were treated with vinorelbine plus cisplatin (VC) regimen. All patients and controls underwent conventional two-dimensional echocardiography and STE at baseline to assess their LV functions. The echocardiographic examinations of NSCLC patients were repeated after the chemotherapy regimens.ResultsNone of the NSCLC patients developed any signs or symptoms of clinical heart failure during or after the chemotherapy. There were not any significant differences in LV ejection fraction between NSCLC patients and controls before and after chemotherapy. There were not any significant differences in baseline LV global longitudinal strain (GLS), radial strain (RS), and circumferential strain (CS) between NSCLC patients and controls. However, all LV GLS, RS and CS significantly decreased in patients treated with the PC regimen resulting in a significant difference compared to both VC group and controls while no significant decreases were observed in strain measures in VC group.ConclusionPaclitaxel plus carboplatin, but not VC, may induce subclinical cardiotoxicity in patients with NSCLC, which may be detected by STE.     

Comparison of Displacement Tracking Algorithms for in Vivo Electrode Displacement Elastography

Hepatocellular carcinoma and liver metastases are common hepatic malignancies presenting with high mortality rates. Minimally invasive microwave ablation (MWA) yields high success rates similar to surgical resection. However, MWA procedures require accurate image guidance during the procedure and for post-procedure assessments. Ultrasound electrode displacement elastography (EDE) has demonstrated utility for non-ionizing imaging of regions of thermal necrosis created with MWA in the ablation suite. Three strategies for displacement vector tracking and strain tensor estimation, namely coupled subsample displacement estimation (CSDE), a multilevel 2-D normalized cross-correlation method, and quality-guided displacement tracking (QGDT) have previously shown accurate estimations for EDE. This paper reports on a qualitative and quantitative comparison of these three algorithms over 79 patients after an MWA procedure. Qualitatively, CSDE presents sharply delineated, clean ablated regions with low noise except for the distal boundary of the ablated region. Multilevel and QGDT contain more visible noise artifacts, but delineation is seen over the entire ablated region. Quantitative comparison indicates CSDE with more consistent mean and standard deviations of region of interest within the mass of strain tensor magnitudes and higher contrast, while Multilevel and QGDT provide higher CNR. This fact along with highest success rates of 89% and 79% on axial and lateral strain tensor images for visualization of thermal necrosis using the Multilevel approach leads to it being the best choice in a clinical setting. All methods, however, provide consistent and reproducible delineation for EDE in the ablation suite.     

Effect of hydration and crack orientation on crack-tip strain,crack opening displacement and crack-tip shielding in elephant dentin

Objectives

To quantify the extent of crack-tip plasticity, crack opening displacement (COD) and crack bridging for crack growth perpendicular (HAH) and parallel (RAR) to the tubules in elephant dentin under both hydrated and dry conditions to better understand their influence on intrinsic and extrinsic toughening during crack growth.

实时剪切波弹性成像评价兔单纯性脂肪肝肝硬度

目的 采用实时剪切波弹性成像(SWE)技术监测兔单纯性脂肪肝在不同时间段的硬度。方法 将60只雄性日本大耳白兔随机分为两组,高脂组及对照组各30只。对高脂组喂养高脂饲料建立单纯性脂肪肝模型,对照组喂饲基础饲料,采用SWE测量两组肝脏不同时间段(喂养前,喂养后4、8、12、16周)的弹性模量值。结果 12周后,高脂组肝脏弹性模量最大值和平均值均高于对照组,差异有统计学意义(P均<0.05)。平均弹性模量值与病理分期呈正相关(r=0.60,P=0.03)。结论 SWE可定量测量脂肪肝硬度并准确地评价脂肪肝程度。     

实时剪切波技术评价急性缺血性脑卒中患者颈动脉纵向弹性模量

目的 探讨采用实时剪切波弹性成像(SWE)检测急性缺血性脑卒中患者颈动脉纵向弹性模量的可行性。方法 选取急性缺血性脑卒中(AIS)患者179例(脑卒中组),其中大动脉粥样硬化性脑梗死(LAA)103例,腔隙性脑梗死(LAC)患者76例。另选取年龄、性别匹配的正常对照组168例。采用超声射频技术测量双侧颈动脉脉搏波传导速度(PWV)。SWE检测双侧颈动脉浅壁20个ROI纵向平均弹性模量的平均值(ME_mean)、最大弹性模量的平均值(ME_max)和最小弹性模量的平均值(ME_min)。分析影响动脉僵硬度的相关因素。结果 ①与对照组相比,脑卒中患者颈动脉僵硬度参数PWV增大、颈动脉浅壁纵向弹性模量参数ME_mean和ME_max增大(P均<0.05)。②所有受试者ME_mean和ME_max与年龄、收缩压、颈动脉管径、PWV和低密度脂蛋白胆固醇呈正相关,与总胆固醇呈负相关(P均<0.05)。结论 采用SWE可通过检测颈动脉纵向弹性模量评价动脉僵硬度。     

Multiparametric Sonography of Testicular Hematomas

We investigated the appearances of intratesticular hematomas on multiparametric sonography combining grayscale, color Doppler, and contrast‐enhanced sonography and strain elastography. Over a 3‐year period, 17 hematomas in 8 patients were analyzed. Blunt trauma (n = 7) and surgery (n = 1) were preceding events. Grayscale sonography showed well‐defined oval or round predominantly hypoechoic and heterogeneous, peripherally (n = 13) or centrally (n = 4) located lesions. Three showed contrast enhancement of septations, and 4 showed peripheral lesion rim enhancement. On strain elastography, the mean strain ratio was 1.19 (range, 0.41–2.36), and elasticity score were 3 or lower (n = 13) and 5 (n = 4). Multiparametric sonography shows nonenhancement with contrast and predominantly “soft” elastographic properties and aids in the interpretation of the benign nature of intratesticular hematomas.     

Validation of in vivo 2D displacements from spiral cine DENSE at 3T

Background

Displacement Encoding with Stimulated Echoes (DENSE) encodes displacement into the phase of the magnetic resonance signal. Due to the stimulated echo, the signal is inherently low and fades through the cardiac cycle. To compensate, a spiral acquisition has been used at 1.5T. This spiral sequence has not been validated at 3T, where the increased signal would be valuable, but field inhomogeneities may result in measurement errors. We hypothesized that spiral cine DENSE is valid at 3T and tested this hypothesis by measuring displacement errors at both 1.5T and 3T in vivo.

Methods

Two-dimensional spiral cine DENSE and tagged imaging of the left ventricle were performed on ten healthy subjects at 3T and six healthy subjects at 1.5T. Intersection points were identified on tagged images near end-systole. Displacements from the DENSE images were used to project those points back to their origins. The deviation from a perfect grid was used as a measure of accuracy and quantified as root-mean-squared error. This measure was compared between 3T and 1.5T with the Wilcoxon rank sum test. Inter-observer variability of strains and torsion quantified by DENSE and agreement between DENSE and harmonic phase (HARP) were assessed by Bland-Altman analyses. The signal to noise ratio (SNR) at each cardiac phase was compared between 3T and 1.5T with the Wilcoxon rank sum test.

Results

The displacement accuracy of spiral cine DENSE was not different between 3T and 1.5T (1.2 ± 0.3 mm and 1.2 ± 0.4 mm, respectively). Both values were lower than the DENSE pixel spacing of 2.8 mm. There were no substantial differences in inter-observer variability of DENSE or agreement of DENSE and HARP between 3T and 1.5T. Relative to 1.5T, the SNR at 3T was greater by a factor of 1.4 ± 0.3.

Conclusions

The spiral cine DENSE acquisition that has been used at 1.5T to measure cardiac displacements can be applied at 3T with equivalent accuracy. The inter-observer variability and agreement of DENSE-derived peak strains and torsion with HARP is also comparable at both field strengths. Future studies with spiral cine DENSE may take advantage of the additional SNR at 3T.