Lin-Xue Qian

Contrast-enhanced ultrasound versus conventional ultrasound in the diagnosis of polypoid lesion of gallbladder: A multi-center study of dynamic microvascularization

OBJECTIVE To assess the value of contrast-enhanced ultrasound (CEUS) in the diagnosis of polypoid lesions of gallbladder (PLGs). METHODS CEUS was performed to 116 patients (mean age, 49.6 years; range, 21-80 years) with PLGs from 8 university hospitals. 9 cases of biliary sludge were proven by surgery and the remaining 107 cases were confirmed by histopathological examination. The confidence level, diagnostic performance, inter-observer agreement of two independent readers with different experience was assessed. The readers were blind to the imaging and clinical results of the patients. RESULTS There were significant differences between benign and malignant PLGs in patient age, gender, lesion size, echogenicity, stalk, time-to-peak, vascularity on CEUS, enhancement pattern, and wall destruction. The confidence levels increased significantly and the interobserver agreement increased from 0.425 to 0.601 after CEUS. The sensitivity increased from 22.2 to 77.8% after CEUS in the staff radiologist, and from 22.2 to 66.7% in the resident radiologist. The correctly characterized lesions were 64.7% before versus 87.1% after CEUS (P=0.125) for the staff radiologist, and 57.8% versus 70.7% for the resident radiologist (P=0.007). No significance was found in the subgroup of lesions≤1.0 cm before and after CEUS for the two radiologists. CONCLUSIONS CEUS using convex multifrequency probes could detect the dynamic microvascularization of PLGs greater than 1.0 cm and facilitate the differentiation between benign and malignant tumors.

HEPATIC PERFUSION PARAMETERS OF CONTRAST-ENHANCED ULTRASONOGRAPHY CORRELATE WITH THE SEVERITY OF CHRONIC LIVER DISEASE

In the study described here, we introduced a new ratio acquired with contrast-enhanced ultrasonography (CEUS): a liver parenchyma blood supply ratio that differentiates arterial and portal phases. Our purpose was to determine whether this ratio and other liver parenchyma perfusion parameters acquired with CEUS can be correlated with the severity of chronic liver disease. Twelve patients with non-cirrhotic chronic liver disease, 35 patients with cirrhosis (child class A: n = 10; child class B: n = 13; child class C: n = 12) and 21 healthy volunteers were examined by CEUS. Time-intensity curves were drawn for regions of interest located in liver parenchyma and right kidney cortex using QLAB quantification software. The arterial and portal phases were differentiated by the time to the maximum enhancement of right kidney and liver parenchyma perfusion data acquired from the time-intensity curves: the intensity of liver parenchyma perfused by hepatic arterial flow (I(ap)), the intensity of total perfusion of liver parenchyma (I(peak)), the intensity of liver parenchyma perfused by portal venous flow (I(pp)) and the ratio of portal perfusion to total perfusion of liver parenchyma expressed by the parameters I(pp)/I(peak), I(peak), I(pp) and I(pp)/I(peak) significantly decreased in patients with cirrhosis and in patients with non-cirrhotic chronic liver disease, whereas Iap increased. The parameters I(pp), I(peak), I(pp)/I(peak) and Iap correlated with the severity of chronic liver disease (r = -0.938, p < 0.001; r = -0.790, p < 0.001; r = -0.931 p < 0.001; r = 0.31, p < 0.05). The diagnostic accuracy rates for cirrhosis expressed as areas under receiver operating characteristic curves were 0.93 for I(peak), 0.98 for I(pp), 0.98 for I(pp)/I(peak), and 0.69 for I(ap). Liver parenchyma perfusion parameters obtained by CEUS were correlated with the severity of chronic liver disease and have the potential to assess cirrhosis non-invasively.

Shear wave elastography results correlate with liver fibrosis histology and liver function reserve

AIM To evaluate the correlation of shear wave elastography (SWE) results with liver fibrosis histology and quantitative function reserve. METHODS Weekly subcutaneous injection of 60% carbon tetrachloride (1.5 mL/kg) was given to 12 canines for 24 wk to induce experimental liver fibrosis, with olive oil given to 2 control canines. At 24 wk, liver condition was evaluated using clinical biochemistry assays, SWE imaging, lidocaine metabolite monoethylglycine-xylidide (MEGX) test, and histologic fibrosis grading. Clinical biochemistry assays were performed at the institutional central laboratory for routine liver function evaluation. Liver stiffness was measured in triplicate from three different intercostal spaces and expressed as mean liver stiffness modulus (LSM). Plasma concentrations of lidocaine and its metabolite MEGX were determined using high-performance liquid chromatography repeated in duplicate. Liver biopsy samples were fixed in 10% formaldehyde, and liver fibrosis was graded using the modified histological activity index Knodell score (F0-F4). Correlations among histologic grading, LSM, and MEGX measures were analyzed with the Pearson linear correlation coefficient. RESULTS At 24 wk liver fibrosis histologic grading was as follows: F0, n = 2 (control); F1, n = 0; F2, n = 3; F3, n = 7; and F4, n = 2. SWE LSM was positively correlated with histologic grading (r = 0.835, P < 0.001). Specifically, the F4 group had a significantly higher elastic modulus than the F3, F2, and F0 groups (P = 0.002, P = 0.003, and P = 0.006, respectively), and the F3 group also had a significantly higher modulus than the control F0 group (P = 0.039). LSM was negatively associated with plasma MEGX concentrations at 30 min (r = -0.642; P = 0.013) and 60 min (r = -0.651; P = 0.012), time to ½ of the maximum concentration (r = -0.538; P = 0.047), and the area under the curve (r = -0.636; P = 0.014). Multiple comparisons showed identical differences in these three measures: significantly lower with F4 (P = 0.037) and F3 (P = 0.032) as compared to F0 and significantly lower with F4 as compared to F2 (P = 0.032). CONCLUSION SWE LSM shows a good correlation with histologic fibrosis grading and pharmacologic quantitative liver function reserve in experimental severe fibrosis and cirrhosis.

Comparison of Different Pulse Waveforms for Local Pulse Wave Velocity Measurement in Healthy and Hypertensive Common Carotid Arteries in Vivo.

Pulse wave velocity (PWV), a measurement of arterial stiffness, can be estimated locally by determining the time delay of the pulse waveforms for a known distance as measured in an ultrasound image. Our aim was to compare three ultrasound-based methods for estimation of local PWV based on the measurement of diameter distension waveforms, displacement waveforms of the anterior wall and displacement waveforms of the posterior wall, respectively, in human common carotid arteries in vivo. The local PWVs at both systolic foot (PWVsf) and dicrotic notch (PWVdn) were estimated from ultrasound radiofrequency data of 25 healthy and 24 hypertensive patients for each method. PWV estimation using the distension waveform method was found to have the highest precision in both groups. Both PWVsf and PWVdn were significantly higher in the hypertensive group compared with the healthy group using the distension waveform method (PWVsf: 6.08 ± 1.70 m/s vs. 4.75 ± 0.92 m/s, p = 0.000014; PWVdn: 7.83 ± 2.26 m/s vs. 5.21 ± 0.95 m/s, p < 0.000001), whereas there was no significant difference at a significance level of 0.01 between the two groups when the anterior or posterior wall waveform method was used. Thus, the difference in arterial stiffness between the two groups could be discriminated well by the distension waveform method. The local PWV estimated using distension waveforms might be a promising index for arterial stiffness characterization and hypertension management.

Contrast-enhanced ultrasound for quantitative assessment of portal pressure in canine liver fibrosis

AIM To explore the feasibility of non-invasive quantitative estimation of portal venous pressure by contrast-enhanced ultrasound (CEUS) in a canine model. METHODS Liver fibrosis was established in adult canines (Beagles; n = 14) by subcutaneous injection of carbon tetrachloride (CCl4). CEUS parameters, including the area under the time-intensity curve and intensity at portal/arterial phases (Qp/Qa and Ip/Ia, respectively), were used to quantitatively assess the blood flow ratio of the portal vein/hepatic artery at multiple time points. The free portal venous pressures (FPP) were measured by a multi-channel baroreceptor using a percutaneous approach at baseline and 8, 16, and 24 wk after CCl4 injections in each canine. Liver biopsies were obtained at the end of 8, 16, and 24 wk from each animal, and the stage of the fibrosis was assessed according to the Metavir scoring system. A Pearson correlation test was performed to compare the FPP with Qp/Qa and Ip/Ia. RESULTS Pathologic examination of 42 biopsies from the 14 canines at weeks 8, 16, and 24 revealed that liver fibrosis was induced by CCl4 and represented various stages of liver fibrosis, including F0 (n = 3), F1 (n = 12), F2 (n = 14), F3 (n = 11), and F4 (n = 2). There were significant differences in the measurements of Qp/Qa (19.85 ± 3.30 vs 10.43 ± 1.21, 9.63 ± 1.03, and 8.77 ± 0.96) and Ip/Ia (1.77 ± 0.37 vs 1.03 ± 0.12, 0.83 ± 0.10, and 0.69 ± 0.13) between control and canine fibrosis at 8, 16, and 24 wk, respectively (all P < 0.001). There were statistically significant negative correlations between FPP and Qp/Qa (r = -0.707, P < 0.001), and between FPP and Ip/Ia (r = -0.759, P < 0.001) in the canine fibrosis model. Prediction of elevated FPP based on Qp/Qa and Ip/Ia was highly sensitive, as assessed by the area under the receiver operating curve (0.866 and 0.895, respectively). CONCLUSION CEUS is a potential method to accurately, but non-invasively, estimate portal venous pressure through measurement of Qp/Qa and Ip/Ia parameters.

Determining the in vivo elastic properties of dermis layer of human skin using the supersonic shear imaging technique and inverse analysis

PURPOSE Human skin consists of several layers including epidermis, dermis, and hypodermis. The determination of the in vivo mechanical properties of an individual skin layer represents a great challenge to date. In this study, the authors explore the use of the supersonic shear imaging (SSI) technique and inverse analysis to determine the in vivo elastic properties of the dermis layer of human skin. METHODS The measurements are conducted on the volar forearms and dorsal forearms of 18 healthy volunteers (nine females and nine males) using the SSI technique that gives the velocities of the shear wave generated by the acoustic force. Finite element analysis is carried out to simulate the propagation of the shear wave in the multilayer soft media and the results are used to interpret the experimental data and deduce the shear modulus of the dermis layer. RESULTS The shear moduli of the skin dermis layer obtained for the 18 healthy volunteers exhibit significant anisotropy. A standard statistical analysis demonstrates the differences between sexes. CONCLUSIONS This study demonstrates that the SSI technique together with the inverse analysis represents a useful tool to characterize the in vivo elastic properties of human skin.

Sonographic measurement of thyroid nodule changes after microwave ablation: relationship between multiple parameters

Abstract Objective: Microwave ablation (MWA) is an effective technique for the treatment of benign thyroid nodules. The aim of this study was to investigate whether it is necessary to study changes in variables other than the volume reduction between follow-up intervals. This study also introduced the index R (Ssurface/V) to explore whether it could reflect features of shape between follow-up intervals. Materials and methods: A total of 236 complex benign thyroid nodules in 230 patients who underwent MWA in our department from October 2013 to February 2017 were included. The Dmax, volume (V), volume reduction ratio (VRR) and index R (Ssurface/V) parameters were evaluated before treatment and postoperatively at 1, 3, 6 and >12 months. Multiple comparisons of these parameters were performed between the baseline and each follow-up period for the entire patient group and subgroups based on diameter and volume. Results: All of the thyroid nodules underwent a significant decrease in size after MWA. The mean decrease in the volume of the thyroid nodules was from 17.40 ± 22.52 mL to 1.31 ± 2.71 mL, with a mean percent decrease of 0.90 ± 0.15% after 12 months. Index R increased over time from 2.55 ± 1.08 to 8.10 ± 5.01, which increased the effectiveness of shape parameterisation between the follow-up periods after the three-month time point, regardless of the initial volume size. For the nodules with a baseline Dmax ≤ 3.4 cm, the V, VRR and index R demonstrated similar capabilities in the evaluation of efficiency before the six-month follow-up visit. Conclusions: Long-term follow-up emphasises changes in the shape and spatial structure of complex benign thyroid nodules, rather than size variations, after effective MWA. Index R, which is the surface area to volume ratio, can also reflect the shape change to some degree.

Diagnostic potential of real-time elastography (RTE) and shear wave elastography (SWE) to differentiate benign and malignant thyroid nodules: A systematic review and meta-analysis

Background: Real-time elastography (RTE) and shear wave elastography (SWE) are noninvasive and easily available imaging techniques that measure the tissue strain, and it has been reported that the sensitivity and the specificity of elastography were better in differentiating between benign and malignant thyroid nodules than conventional technologies. Methods: Relevant articles were searched in multiple databases; the comparison of elasticity index (EI) was conducted with the Review Manager 5.0. Forest plots of the sensitivity and specificity and SROC curve of RTE and SWE were performed with STATA 10.0 software. In addition, sensitivity analysis and bias analysis of the studies were conducted to examine the quality of articles; and to estimate possible publication bias, funnel plot was used and the Egger test was conducted. Results: Finally 22 articles which eventually satisfied the inclusion criteria were included in this study. After eliminating the inefficient, benign and malignant nodules were 2106 and 613, respectively. The meta-analysis suggested that the difference of EI between benign and malignant nodules was statistically significant (SMD = 2.11, 95% CI [1.67, 2.55], P < .00001). The overall sensitivities of RTE and SWE were roughly comparable, whereas the difference of specificities between these 2 methods was statistically significant. In addition, statistically significant difference of AUC between RTE and SWE was observed between RTE and SWE (P < .01). Conclusion: The specificity of RTE was statistically higher than that of SWE; which suggests that compared with SWE, RTE may be more accurate on differentiating benign and malignant thyroid nodules.

Contrast-Enhanced Ultrasonography Diagnostic Evaluation of Esophageal Varices in Patients With Cirrhosis.

Abstract The purpose of this study was to clarify the usefulness of contrast-enhanced ultrasonography (CEUS) for the diagnosis of esophageal varices (EVs) in patients with cirrhosis. A total of 81 cases (56 patients with EVs and 25 control subjects without EV) were examined by CEUS and by esophagogastroduodenoscopy. According to the esophagogastroduodenoscopy results, we divided the subjects into 3 groups: G0, G1, and G2. The G0 group had 25 patients who exhibited no liver abnormality other than liver cyst or hemangioma without EVs, G1 comprised 9 patients with small EVs and 13 with medium EVs. G2 was composed of 34 cases of severe EVs. Under CEUS, the following parameters were measured: the thickness of double-layer mucosa and submucosa in the lower esophagus (Tm), the maximum anteroposterior diameter of the lower esophagus (De), and the ratio of Tm to De (Tm/De). Time-intensity curves of the lower esophagus and aorta were drawn using QLAB software. One-factor analysis of variance was used to compare means between the 3 groups. The diagnostic value of CEUS was assessed by receiver operating characteristic curves. Bayes discriminant analysis was adopted for building discriminant equations. Tm, De, Tm/De, Tep, and Iep/Iap were greater in patients with EVs (G1 and G2) than in those without EVs (G0). The Tms for the G0, G1, and G2 groups were 4.16 ± 0.59 mm, 7.06 ± 0.89 mm, and 10.10 ± 1.77 mm (P < 0.01), respectively, with 7.65 mm being the best cutoff value for diagnosing ≥ G2 (sensitivity 96.9%, specificity 90.0%). The area under the receiver operating characteristic curve was 0.987. Three discriminant equations were obtained by Bayes discriminant analysis: y 0 = −6.2 + 2.5Tm, y 1 = −15.1 + 4.1Tm and y 2 = −31.7 + 6.0Tm, respectively. The equations correctly classified 91.7% of cases in the study, making an error rate of 8.3%. Tm attained from CEUS can be a new, convenient, noninvasive parameter for evaluating esophageal varices in patients with liver cirrhosis.

New Noninvasive Assessment of Liver Fibrosis in Chronic Hepatitis B Maximal Accumulative Respiration Strain

Objective. A novel parameter acquired from conventional B‐mode sonographic videos was introduced in this study, and its diagnostic accuracy for evaluation of hepatic fibrosis was investigated. Methods. Twenty‐eight patients with chronic hepatitis B and 8 patients with hepatic cysts in the right lobe (controls) were enrolled. B‐mode sonographic videos of hepatic motion under the ensisternum in the sagittal plane were captured during peaceful breathing. Maximal accumulative respiration strain (MARS) values of hepatic tissue were obtained after image analysis. METAVIR scoring after liver biopsy was considered the standard. First, the relationship between MARS and the fibrotic stage was studied; and second, receiver operating characteristic (ROC) curves were used to assess the accuracy of MARS for evaluation of the fibrotic stage. Results. When the transducer was placed in the sagittal imaging plane under the ensisternum during the whole respiratory period, the hepatic tissue motion was almost in the same plane. The MARS values (mean ± SD) were 29.44% ± 10.44% in the F0 group (no fibrosis; n = 8), 19.30% ± 9.10% in the F1 group (portal fibrosis without septa; n = 8), 18.09% ± 7.36% in the F2–F3 group (portal fibrosis with few septa or numerous septa without cirrhosis; n = 12), and 14.16% ± 4.18% in the F4 group (cirrhosis; n = 8). The Spearman correlation coefficient between MARS and the fibrotic stage was 0.516 (P = .001). The diagnostic accuracy rates, expressed as areas under the ROC curves, were 0.87 for mild fibrosis (F ≥ 1), 0.72 for substantial fibrosis (F ≥ 2), and 0.75 for cirrhosis (F = 4). Conclusions. Maximal accumulative respiration strain attained from B‐mode sonographic videos of hepatic tissue is a new, convenient, economical, and promising noninvasive parameter for assessment of hepatic fibrosis in patients with chronic hepatitis B.