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This study aimed to assess liver fibrosis by contrast-enhanced ultrasound (CEUS) and point shear-wave elastography (pSWE) in rabbits and compare the performance of the two techniques. Eighty rabbits were divided into experimental (n=60) and control group (n=20). In the experimental group, liver fibrosis (F1-F4) was induced by subcutaneous injection of carbon tetrachloride. CEUS and pSWE of the liver was performed for the two groups at a 4-week interval for 40 weeks. The portal vein rise time (PV-RT), time to peak (PV-TTP), mean transit time (PV-MTT) and the maximum signal intensity (PV-Imax) were analyzed with time-intensity curves (TICs). Liver stiffness value (LSV) was obtained through pSWE. Histologic examination of liver specimens of the rabbits was performed to evaluate the fibrosis stage. PV-RT, PV-TTP, PV-Imax and LSV were significantly different among five liver fibrosis stages (F0-F4) (P<0.01). PV-Imax and LSV displayed better diagnostic performance than PV-RT, PV-TTP, PV-MTT. For diagnosing≥F1 stage fibrosis, the area under the receiver operating characteristic curve (AUROC) of PV-Imax was 0.870, which was similar to that of LSV 0.874 (P=0.94). For diagnosing ≥F2, ≥F3 and ≥F4 stage fibrosis, the AUROC of PV-Imax and LSV was 0.845 vs. 0.956 (P=0.04), 0.789 vs. 0.954 (P=0.01) and 0.707 vs. 0.933 (P=0.03). Both CEUS and pSWE had the potential to be complementary imaging tools in the evaluation of liver fibrosis. The performance of pSWE may be better than CEUS.

This study aimed to assess the severity of fatty liver (FL) by analyzing ultrasound radiofrequency (RF) signals in rats. One hundred and twenty rats (72 in the FL group and 48 in the control group) were used for this purpose. Histological results were the golden standard: 42 cases had normal livers (N), 30 cases had mild FL (L1), 25 cases had moderate FL (L2), 13 cases presented with severe FL (L3), and 10 cases were excluded from the study. Four RF parameters (Mean, Mean/SD ratio [MSR], skewness [SK], and kurtosis [KU] were extracted. Univariate analysis, spearman correlation analysis, and stepwise regression analysis were used to select the most powerful predictors. Receiver operating characteristic (ROC) analysis was used to compare the diagnostic efficacy of single indexes with a combined index (Y) expressed by a regression equation. Mean, MSR, SK, and KU were significantly correlated with FL grades (r=0.71, P<0.001; r=0.81, P<0.001; r=-0.79, P<0.001; and r=-0.74, P<0.001). The regression equation was Y=-4.48 + 3.20 × 10 -2 X1 + 3.15X2 (P<0.001), where Y=hepatic steatosis grade, X1 =Mean, and X2 =MSR. ROC analysis showed that the curve areas of the combined index (Y) were superior to simple indexes (Mean, MSR, SK, and KU) in evaluating hepatic steatosis grade, and they were 0.95 (L≥L1), 0.98 (L≥L2), and 0.99 (L≥L3). Ultrasound radiofrequency signal quantitative technology was a new, noninvasive, and promising sonography-based approach for the assessment of FL.

The purpose of this study was to investigate whether ultrasound elastography reflects liver function reserve relative to liver fibrosis histology. Sixty-five New Zealand rabbits were divided into an experimental group (n = 45) and a control group (n = 20). In the experimental group, liver fibrosis (F1-F4) was induced by subcutaneous injection of carbon tetrachloride. Point shear wave elastography and the indocyanine green (ICG) elimination test were performed for the two groups at 4-wk intervals for 56 wk. The liver stiffness value (LSV) and the ICG retention rate at 15 min (ICGR15) were obtained, and the correlation between them was investigated. The median LSVs of stages F0-F4 were 3.92 kPa (1.91-8.53 kPa), 5.02 kPa (2.39-8.91 kPa), 7.87 kPa (5.21-12.26 kPa), 12.83 kPa (5.92-16.79 kPa) and 16.64 kPa (9.76-29.50 kPa), respectively. The median ICGR15 values of stages F0-F4 were 8.7% (4.8%-15.6%), 10.8% (5.6%-20.3%), 19.2% (12.3%-26.7%), 31.0% (20.9%-41.0%) and 45.6% (22.1%-60.9%). There were significant differences in LSVs and ICGR15 values among the different stages of liver fibrosis (p <0.01). A positive correlation was observed between LSV and ICGR15 (r = 0.7497, p < 0.0001). A strong correlation was observed between liver stiffness and liver function reserve, indicating ultrasound elastography may reflect liver function reserve in different degrees of liver fibrosis., (Copyright © 2018. Published by Elsevier Inc.)

Focal fatty change (FFC) may mimic liver mass on conventional B-mode ultrasound. Clinical differentiation of mass-like FFC and liver mass is important due to different clinical interventions. Contrast-enhanced imaging (CEI) or biopsy is reliable for this differentiation, but is expensive and invasive. This study aimed to explore utilities of ultrasound elastography for this differentiation.This study enrolled 79 patients with focal liver lesions (FLLs), of which 26 were mass-like FFC confirmed by at least 2 CEI modalities. The other 53 were liver masses, confirmed by pathology (n = 28) or at least 2 CEI modalities (n = 25). Lesion stiffness value (SV), absolute stiffness difference (ASD), and stiffness ratio (SR) of lesion to background were obtained using point shear-wave elastography (pSWE) and compared between FFC group and liver mass group. The performance of SV, ASD, and SR for identifying FFC from liver mass was evaluated.SV was 5.6 ± 2.4 versus 16 ± 12 kPa, ASD was 2.0 ± 1.9 versus 11 ± 12 kPa, and SR was 1.4 ± 0.6 versus 3.0 ± 1.9 for FFC and liver mass group, respectively (P < .0001). The area under the receiver operating characteristic curve of SV, ASD, and SR for discriminating mass-like FFC and liver mass was 0.840, 0.842, and 0.791, respectively (P < .05). Particularly, with cut-off ASD < 1.0 kPa, positive predictive value was 100%, specificity was 100%, and accuracy was 82% for diagnosing FFC.pSWE may be a potential useful modality for identifying mass-like FFC from liver mass, which might help reduce the necessity for further CEI or biopsy for diagnosing mass-like FFC.

Objectives: This study aimed to analyze the patterns of conventional ultrasound (CUS) and contrast-enhanced ultrasound (CEUS) in 20 patients with diagnosis of hepatic epithelioid hemangioendothelioma (HEHE). Methods: Twenty patients (12 females and 8 males) with mean age of 43.6 ± 13.6 years were included in this study from January 2012 to May 2020. CUS, CEUS, computed tomography (CT) and magnetic resonance imaging (MRI) features of the twenty patients with histologically proven HEHE were retrospectively reviewed by two radiologists. The clinical manifestations and the pathological findings of all patients with HEHE are described. Results: There were 3 types of HEHE in imaging, including single nodular (8/20, 40%), multifocal nodular (10/20, 50%), and diffuse type (2/20, 10%). The mean size of lesions was 4.2 ± 2.6 cm. B-mode ultrasound of HEHE showed hypoechoic (15/20, 75%), heterogeneous echogenicity (4/20, 20%), or hyperechoic (1/20, 5%) lesions with regular shape (18/20, 90%) near the liver capsule (17/20, 85%), and occasionally with a halo (4/20, 20%) and calcifications (3/20, 15%). Eight out of the 20 patients also had CEUS. On CEUS, HEHE demonstrated peripheral rim-like (5/8, 62.5%), heterogeneous (2/8, 25%), or homogeneous (1/8, 12.5%) hyperenhancement in the arterial phase. All patients (8/8, 100%) showed hypoenhancement in the portal and late phase. CEUS detected more lesions than CUS in 3 patients (3/8, 37.5%). In addition, central irregular unenhanced zones were observed in 6 patients (6/8, 75%). On contrast-enhanced CT or MRI, most cases presented with capsule retraction sign and lollipop sign. Conclusions: HEHE demonstrated specific findings on ultrasound, which includes multifocal hypoechoic lesions in a subcapsular distribution with typical enhancement characteristics of malignant hepatic tumors. [ABSTRACT FROM AUTHOR]

Purpose: Liver disease causes significant morbidity and mortality worldwide. Liver imaging plays an essential role in the noninvasive liver disease evaluation because of the limitation of liver biopsy. This paper aims to image in vivo liver with thermoacoustic imaging (TAI) and demonstrate this liver imaging technique with a cross‐validation method. Methods: The imaging system composed of a large aperture antenna and a flexible transducer array was used, and we performed the position calibration using the delay and sum algorithm. The localization wire was utilized in the cross‐validation of in vivo liver TAI. Results: We successfully validated in vivo liver TAI. In vivo images of different liver lobes without labels were observed. The imaging depth reached about 4 cm. Conclusions: TAI has the potential to image the liver and provide useful dielectric properties of the liver tissue. This study realized the first in vivo liver TAI, suggesting its prospect in detecting liver disease noninvasively. [ABSTRACT FROM AUTHOR]