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Purpose: Contrast-enhanced ultrasound (CEUS) shows different enhancement patterns depending on the time after administration of the contrast agent. The aim of this study was to evaluate the diagnostic performance of liver nodule characterization using our proposed deep learning model with input of nine CEUS images. Methods: A total of 181 liver lesions (48 benign, 78 hepatocellular carcinoma (HCC), and 55 non-HCC malignant) were included in this prospective study. CEUS were performed using the contrast agent Sonazoid, and in addition to B-mode images before injection, image clips were stored every minute up to 10 min. A deep learning model was developed by arranging three ResNet50 transfer learning models in parallel. This proposed model allowed inputting up to nine datasets of different phases of CEUS and performing image augmentation of nine images synchronously. Using the results, the correct prediction rate, sensitivity, and specificity between "benign" and "malignant" cases were analyzed for each combination of the time phase. These accuracy values were also compared with the washout score judged by a human. Results: The proposed model showed performance superior to the referential standard model when the dataset from B-mode to the 10-min images were used (sensitivity: 93.2%, specificity: 65.3%, average correct answer rate: 60.1%). It also maintained 90.2% sensitivity and 61.2% specificity even when the dataset was limited to 2 min after injection, and this accuracy was equivalent to or better than human scoring by experts. Conclusion: Our proposed model has the potential to identify tumor types earlier than the Kupffer phase, but at the same time, machine learning confirmed that Kupffer-phase Sonazoid images contain essential information for the classification of liver nodules. [ABSTRACT FROM AUTHOR]

Purpose: The risk of pelvic floor muscle injury is commonly considered to be higher in vaginal than in cesarean delivery. This study aimed to compare levator ani muscle (LAM) elasticity after vaginal and cesarean delivery using shear wave elastography (SWE). Methods: Postpartum women who underwent a single SWE evaluation 1 month after their first delivery were divided into vaginal and cesarean delivery groups. The elastic moduli of both sides of the LAM were measured in a horizontal section and compared between the groups. In addition, a subgroup analysis was performed to compare LAM elasticity according to the delivery method within the vaginal delivery group—normal vaginal delivery, episiotomy, and operative vaginal delivery. Results: Sixty-two women were included (vaginal delivery, n = 47; elective cesarean section, n = 15). Multiple regression analysis revealed that the LAM elastic modulus was significantly lower in the vaginal delivery group than in the cesarean delivery group (right LAM: 44.2 vs. 72.7 kPa, p = 0.0036; left LAM 40.4 vs. 82.7 kPa, p < 0.0001). In the subgroup analysis, the right LAM elastic modulus was significantly lower in the operative vaginal delivery subgroup than in the normal vaginal delivery subgroup (p = 0.0131). However, there was no significant difference in the left LAM elastic modulus between the three subgroups. Conclusion: LAM elasticity was significantly lower after vaginal delivery than after cesarean delivery. Furthermore, the elasticity of the right LAM was lower after operative vaginal delivery than after normal vaginal delivery. SWE has the potential to provide an objective quantitative assessment of postpartum pelvic floor muscle recovery. [ABSTRACT FROM AUTHOR]

Purpose: Deep attenuation transducers (DAX) are capable of imaging at diagnostic depths of up to 40 cm. The feasibility of DAX for liver stiffness measurement (LSM) has not been reported clinically. We aimed to assess the feasibility and reliability of DAX for LSM. Methods: Overall, 219 patients with chronic liver disease were enrolled. The success rate (acquired after ≥ 10 valid measurements) and inadequate measurements (interquartile range/median ≥ 0.3) for DAX were compared with those of conventional convex (c-convex) probes and M and XL probes of vibration-controlled transient elastography. Results: LSM was successfully performed for all patients using DAX through all degrees of skin-to-liver capsular distance (SCD). Especially in patients with an SCD ≥ 30 mm, the difference in the rate of acquisition of 10 valid measurements was remarkable: M probe (8/33, 24.2%), XL probe (26/33, 78.8%), c-convex probe (33/43, 76.7%), and DAX (44/44, 100%). In patients with an SCD ≥ 30 mm, the inadequate measurement rate of M probe (1/8, 12.5%), XL probe (8/26, 30.8%), and c-convex probe (6/33, 18.2%) was higher than that of DAX (1/43, 2.3%). The areas under the curve for diagnosis of F4 with shear wave speed by c-convex and DAX were 0.916 and 0.918, respectively. Between DAX and c-convex probes, the intraclass correlation coefficient of 0.937 (95% CI 0.918–0.952) was excellent. Bland–Altman plots revealed that there was no statistically significant bias. Conclusion: Liver stiffness measured by DAX is feasible and reliable for all patient populations, while the XL probe is limited to use in obese patients. [ABSTRACT FROM AUTHOR]

Purpose: Previous reports suggest that contrast-enhanced ultrasonography (CEUS) is useful for predicting the efficacy of sorafenib and lenvatinib treatment. However, there are no reports on the utility of CEUS for predicting the efficacy of atezolizumab plus bevacizumab combination therapy (Atezo + Bev). This study aimed to identify CEUS parameters for predicting the efficacy of Atezo + Bev. Methods: A total of 30 patients with hepatocellular carcinoma (HCC) treated with Atezo + Bev who underwent CEUS before and 5 weeks after treatment initiation were included. Results: Post area under the curve (post AUC) was identified as a predictive factor for early progressive disease (PD). The optimal cut-off value of post AUC for predicting progression-free survival (PFS) was 61.3. Conclusion: The results of this study suggest that CEUS at 5 weeks after initiation of Atezo + Bev may predict PFS in HCC patients. Changes to the treatment plan may need to be considered in patients with post AUC > 61.3. [ABSTRACT FROM AUTHOR]

Purpose: Blood flow reduction after initiation of lenvatinib therapy may not always indicate tumor necrosis. This study aimed to compare the blood flow detectability of contrast-enhanced ultrasonography (CEUS), contrast-enhanced computed tomography (CT), and contrast-enhanced magnetic resonance imaging (MRI) in hepatocellular carcinoma (HCC) during lenvatinib therapy. Methods: A total of 12 cases underwent CEUS and contrast-enhanced CT/MRI within 2 weeks during lenvatinib therapy. Vascularity on CEUS and CT/MRI was compared. Results: At the time of CEUS examination, the median period from the start of lenvatinib was 227 ± 210 (31–570) days. CEUS showed hyperenhancement in eight cases (66.7%), hypoenhancement in two cases (16.7%), and no enhancement in one case (8.3%), while CT/MRI showed hyperenhancement in one case (8.3%), ring enhancement in three cases (25.0%), and hypoenhancement in eight cases (66.7%) (p = 0.007). Transarterial chemoembolization (n = 3), radiofrequency ablation (n = 2), and stereotactic body radiation therapy (n = 2) were performed after blood flow detection by CEUS. Conclusions: The viability of the HCC should be confirmed using CEUS when contrast-enhanced CT/MRI reveals lesion hypoenhancement during lenvatinib therapy. [ABSTRACT FROM AUTHOR]

The accuracy of attenuation coefficients and B-mode ultrasound for distinguishing between S0 (healthy, < 5% fat) and S1–3 (steatosis ≥ 5%) livers compared to a controlled attenuation parameter is unclear. This meta-analysis aimed to comprehensively assess the diagnostic performance of B-mode ultrasound imaging for evaluating steatosis of ≥ 5%. We searched the PubMed, Embase, and Web of Science databases for studies on the accuracy of B-mode ultrasound for differentiating S0 from S1–3 in adults with chronic liver disease. A bivariate random-effects model was performed to estimate the pooled sensitivity, specificity, positive (PLR) and negative likelihood ratios (NLR), and diagnostic odds ratios (DORs). Subgroup analyses by attenuation coefficient, conventional B-mode ultrasound findings, and B-mode ultrasound findings without semi-quantification methods were performed. Liver steatosis was scored as follows: S0, < 5%; S1, 5–33%; S2, 33–66%; and S3, > 66%. Nineteen studies involving 3240 patients were analyzed. The pooled sensitivity and specificity of B-mode ultrasound for detecting S1 were 0.70 (95% confidence interval [CI], 0.63–0.77) and 0.86 (95% CI 0.82–0.89), respectively. The pooled PLR, NLR, and DOR were 4.90 (95% CI 3.69–6.51), 0.35 (95% CI 0.27– 0.44), and 14.1 (95% CI 8.7–23.0), respectively. The diagnostic accuracy was better in patients with attenuation coefficients (area under the curve [AUC], 0.89; sensitivity, 0.75; specificity, 0.86) than in those with conventional B-mode findings (AUC, 0.80; sensitivity, 0.59; specificity, 0.83). In particular, the diagnostic value was better when the attenuation coefficient guided by B-mode ultrasound was utilized. To screen patients with steatosis of ≥ 5%, attenuation coefficient should be used. [ABSTRACT FROM AUTHOR]

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease, with an incidence of 20–40% worldwide, making it a major healthcare problem. Because NAFLD can progress to liver fibrosis and cirrhosis through non-alcoholic steatohepatitis, early detection and monitoring of hepatic steatosis are essential for management of NAFLD patients. Even though conventional B-mode ultrasound (US) has been widely used for the evaluation of NAFLD owing to its safety and easy accessibility, its subjective nature and limited accuracy in detecting mild steatosis are major limitations. To overcome the current limitations of conventional B-mode US, attenuation imaging (ATI) based on two-dimensional B-mode US has been developed. ATI can quantitatively assess the degree of hepatic steatosis by calculating the attenuation coefficient, which reflects the degree of US beam attenuation transmitted into the liver tissue. After the first study was published in 2019, several clinical studies using ATI to evaluate hepatic steatosis have reported promising results. In this review, the basic physics, measurement protocol, and reported diagnostic accuracy of ATI in evaluating hepatic steatosis will be discussed. [ABSTRACT FROM AUTHOR]

Although new ultrasound (US) methods able to quantitatively assess liver fat content have been recently developed, B-mode US is still the major method for detecting liver steatosis during medical checkups. However, some pathological cases yield false-positive or false-negative liver steatosis results using B-mode US. In addition, histologically, the degree of fat deposits and the size of fat droplets in the liver can affect the sensitivity and specificity of the diagnosis of liver steatosis using B-mode US. As B-mode US evaluation of fatty liver relies on operator expertise, the operator should be aware that there are some cases of liver steatosis that are difficult to evaluate with B-mode US. Here, we describe the pathological findings of liver steatosis that is difficult to evaluate with US. [ABSTRACT FROM AUTHOR]

Purpose: Attenuation imaging (ATI) is a new noninvasive ultrasound technique for assessing steatosis grade (S). However, validated region-of-interest (ROI) sampling strategies are not currently available. We investigated the diagnostic performance of various ATI-ROI positions for determining histopathologic S in patients with nonalcoholic fatty liver disease (NAFLD). Methods: This retrospective study included 105 patients with biopsy-proven NAFLD. All attenuation coefficient (AC, dB/cm/MHz) measurements were obtained by the same hepatologist using a commercially available ultrasound system on the same day as liver biopsy. Mean (± standard deviation) age and body mass index of the patients were 53 (± 18) years and 27.1 (± 4.1) kg/m2, respectively. The numbers of patients with steatosis affecting < 5%, 5–33%, 33–66%, and > 66% of hepatocytes were 8, 50, 29, and 18, respectively. The ATI-ROI was placed at three different positions for AC measurement using a dedicated workstation: the upper edge of the area ROI, twice the depth of the liver capsule, and the lower edge of the area ROI. Diagnostic performance was evaluated using the area under the receiver-operating characteristic curve (AUC). Results: The AUCs of AC at the three ATI-ROI positions were 0.734 (95% confidence interval [CI]: 0.470–0.998), 0.750 (0.639–0.861), and 0.878 (0.788–0.968) for S ≥ 1; 0.503 (0.392–0.615), 0.824 (0.741–0.907), and 0.809 (0.724–0.895) for S ≥ 2; and 0.606 (0.486–0.726), 0.849 (0.767–0.932), and 0.737 (0.626–0.848) for S = 3, respectively. Conclusion: For accurate steatosis grade assessment, the ATI-ROI should not be placed at the upper edge of the area ROI. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the diagnostic accuracy of the ultrasound-guided attenuation parameter (UGAP) using the LOGEQ E10 for hepatic steatosis in non-alcoholic fatty liver disease (NAFLD) patients and directly compare UGAP with attenuation imaging (ATI) and controlled attenuation parameter (CAP). We prospectively analyzed 105 consecutive patients with NAFLD who underwent UGAP, ATI, CAP, and liver biopsy on the same day between October 2019 and April 2021. The diagnostic ability of the UGAP-determined attenuation coefficient (AC) was evaluated using receiver operating characteristic (ROC) curve analysis, and its correlation with ATI-determined AC values or CAP values was investigated. The success rate of UGAP was 100%. The median IQR/med obtained by UGAP was 4.0%, which was lower than that of ATI and CAP (P < 0.0001). The median ACs obtained by UGAP for grades S0 (control), S1, S2, and S3 were 0.590, 0.670, 0.750, and 0.845 dB/cm/MHz, respectively, demonstrating a stepwise increase with increasing hepatic steatosis severity (P < 0.0001). The areas under the ROC curve of UGAP for identifying ≥ S1, ≥ S2, and S3 were 0.890, 0.906, and 0.912, respectively, which were significantly better than the results obtained with CAP for identifying S3. Furthermore, the correlation coefficient between UGAP-AC and ATI-AC values was 0.803 (P < 0.0001), indicating a strong relationship. Our results indicate that UGAP has high diagnostic accuracy for detecting and grading hepatic steatosis in patients with NAFLD. [ABSTRACT FROM AUTHOR]

Purpose: Measurement of spleen stiffness (SS) using ultrasound (US) elastography is useful for predicting portal hypertension. However, the mechanism leading to increased SS remains unclear. We jointly developed a new US elastography system (Aplio i-series, Canon Medical Systems) that can easily measure organ viscosity (dispersion slope: DS). We analyzed the cause of increased SS by calculating the shear wave speed (SWs, which reflects fibrosis) and DS of the spleen in carbon tetrachloride (CCL4) rat liver cirrhosis models. Methods: A total of 13 Sprague–Dawley rats were randomly divided into four groups (C group: 3 rats as control, 2D group: 3 rats injected with CCL4 twice in 1 week, 4D group: 4 rats injected 4 times in 1 week, 6W group: 3 rats injected twice a week for 6 weeks). The SWs and the DS of each group were calculated, and histopathological analysis was performed. Results: The spleen SWs of the 6W group was significantly higher than that of the C group (p = 0.044). The spleen DS did not change after CCL4. The liver SWs of the 4D and 6W groups was significantly higher than that of the C group (p = 0.012 and 0.007, respectively) with fibrosis change on histopathology, and the DS of the 4D group was significantly higher than that of the C group (p = 0.033). Splenic fibrosis was confirmed in the 6W group, but inflammation and necrosis were not seen. Conclusion: SS increased due to fibrosis and can be predicted based on SWs and DS values. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to clarify the normal values obtained by simultaneous use of shear wave imaging and strain imaging (combinational elastography) in liver and reveal how aging influences them. Methods: In our checkup center, 257 examinees were diagnosed with normal liver based on questionnaires about liver disease and their drinking history, liver function test results, and ultrasound B-mode study findings. We estimated the values of combinational elastography and considered the correlation between the values and age. A multivariate analysis was performed concerning several features and the liver fibrosis (LF) index. We divided examinees into a younger group (< 65 years old) and an older group (≥ 65 years old), and assessed the effect of age on the LF index. Results: The mean shear wave velocity (Vs) of shear wave measurement (SWM) was 1.10 ± 0.17 m/s (range 0.84–1.93), and the mean LF index of real-time tissue elastography (RTE) was 1.371 ± 0.458 (range 0.258–3.173). There was no significant correlation between Vs and age. However, the LF index increased significantly with age. The multivariate analysis showed that age (P < 0.001) and BMI (P < 0.05) significantly affected the LF index. Indeed, the LF index in the older group was significantly higher than that in the younger group (P < 0.001). Conclusion: In adult liver, the normal Vs of SWM was 1.10 ± 0.17 m/s, and the normal LF index of RTE was 1.371 ± 0.458. The LF index increased significantly with age in contrast to Vs; therefore, the influence of age should be considered when using combinational elastography. [ABSTRACT FROM AUTHOR]

Purpose: By analyzing possible factors contributing to imaging misevaluation of arterial phase (AP) vascularity, we aimed to provide a more proper way to detect AP hypervascularity of hepatocellular carcinomas (HCCs) using the noninvasive imaging modalities magnetic resonance imaging (MRI) and contrast-enhanced ultrasound (CEUS). Methods: We retrospectively recruited 164 pathologically confirmed HCC lesions from 128 patients. Using CEUS with Sonazoid (SCEUS) and gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid MRI (EOB-MRI), AP vascularity of the lesions was evaluated and inconsistencies in interpretation were examined. Indicators of margin, echogenicity, and halo and mosaic signs of lesions on grayscale US; depth of lesions on SCEUS; and tumoral homogeneity, signal contrast ratio of lesions to the surrounding area on precontrast and AP images on EOB-MRI, and histological grade were investigated. Results: When precontrast images were used to adjust the AP enhancement ratio, the proportion of inconsistent interpretations of AP vascularity declined from 26.2% (43/164; 29 non-hypervascularity instances using EOB-MRI and 14 using SCEUS) to 16.5% (27/164; 7 using EOB-MRI and 20 using SCEUS). Greater lesion depth (P = 0.017), ill-defined tumoral margin (P = 0.028), absence of halo sign (P = 0.034), and histologically early HCC (P = 0.007) on SCEUS, and small size (P = 0.012) and heterogeneity (P = 0.013) of lesions and slight enhancement (low AP enhancement ratio) (P = 0.018 and 0.009 before and after adjustment) on EOB-MRI, may relate to undetectable hypervascularity. Conclusions: SCEUS and EOB-MRI may show discrepancies in evaluating AP vascularity in the case of deep, ill-defined, heterogeneous, slightly enhanced lesions, and histologically early HCCs. We recommend adjusting AP with precontrast images in EOB-MRI, and combining both modalities to detect hypervascularity. [ABSTRACT FROM AUTHOR]

Purpose: Shear wave elastography (SWE) using transabdominal ultrasonography (US) is widely used for diagnosis of tissue stiffness. Ultrasound shear wave dispersion (SWD) enables evaluation of tissue viscosity using SWE. The objective of this study was to investigate the reliability and clinical significance of SWD in pancreatic screening. Methods: SWE and SWD were measured in 76 patients examined by US in pancreatic screenings performed between November 2017 and November 2018. The median pancreatic elastic modulus (PEM) and dispersion slope were obtained from at least five measurements. The reproducibility of these values and their correlations with patient characteristics, pancreatic echogenicity, and the pancreas-to-spleen attenuation ratio (P/S) on plain CT, which is associated with fatty change in pancreatic parenchyma, were investigated retrospectively. Results: The median PEM and dispersion slope were 7.4 kPa and 15.7 (m/sec)/kHz, respectively, and both values had high intraclass correlation coefficients, showing high reproducibility (ρ = 0.869 and ρ = 0.867, respectively). The interquartile range/median value of PEM and dispersion slope were 0.36 and 0.28, respectively. PEM had a positive correlation with age (rs = 0.348, p = 0.002), and dispersion slope was positively correlated with age (rs = 0.278, p = 0.016) and BMI (rs = 0.397, p < 0.001). The hyperechoic pancreas had significantly higher PEM (6.6 vs. 7.8 kPa, p = 0.037) and dispersion slope (13.2 vs. 16.3 (m/sec)/kHz, p < 0.001). On plain CT performed in 50 patients, the P/S was not correlated with PEM (rs = − 0.180, p = 0.221), but was inversely correlated with dispersion slope (rs = − 0.338, p = 0.019). Conclusion: Measurement of SWD in pancreatic screening was highly reproducible and may permit objective evaluation of fatty change of the pancreas. [ABSTRACT FROM AUTHOR]

Ultrasonography (US) is a major, sustainable hepatocellular carcinoma (HCC) surveillance method as it provides inexpensive, real-time, and noninvasive detection. Since US findings are based on pathological features, knowledge of pathological features is essential for delivering a correct US diagnosis. Recent advances in US equipment have made it possible to provide more information, such as malignancy potential and accurate localization diagnosis of HCC. Evaluation of malignancy potential is important to determine the treatment strategy, especially for small HCC. Diagnosis of blood flow dynamics using color Doppler and contrast-enhanced US is one of the most definitive approaches for evaluating HCC malignancy potential. Recently, a new Doppler microvascular imaging technique, superb microvascular imaging, which can detect Doppler signals generated by low-velocity blood flow, was developed. A fusion imaging system, another innovative US technology, has already become an indispensable technology over the last few years not only for US-guided radiofrequency ablation but also for the detection of small, invisible HCC. This article reviews the evidence on the use of ultrasound and contrast-enhanced ultrasound with Sonazoid for the practical management of HCC. [ABSTRACT FROM AUTHOR]

With advances in imaging technology, images from ultrasound (US) and computed tomography (CT) or magnetic resonance imaging (MRI) can be displayed simultaneously and in real time, according to the angle of the transducer. CT/MR–US fusion imaging improves the visualization of inconspicuous hepatocellular carcinoma (HCC) and helps us to understand the three-dimensional relationship between the liver vasculature and HCC. US fusion imaging guidance facilitates improvement in the treatment response for HCC with poor conspicuity, and the rates of technical success of ablation and local tumor progression for inconspicuous HCC range from 94.4 to 100% and 0 to 8.3%, respectively. Moreover, the development of image fusion has made it possible to compare and overlay pre- and post-ablation US images. This US–US fusion imaging allows side-by-side comparison of the ablative margin, while US–US overlay fusion can visualize the ablative margin because the tumor image is projected onto the ablative hyperechoic zone. Thus, US–US overlay fusion guidance is highly effective for safety margin achievement in local ablation therapy for HCC, providing a lower risk of local tumor progression. This manuscript reviews the current status of ultrasound fusion imaging for percutaneous ablation therapy of HCC. [ABSTRACT FROM AUTHOR]

Purpose: We previously reported that hepatocellular carcinoma (HCC) changes to a phenotype producing des-γ-carboxy prothrombin (DCP) during epithelial mesenchymal transition (EMT) in vitro. To confirm this change in vivo, we evaluated the association between DCP production and HCC hemodynamics in patients undergoing resection as EMT and hemodynamic changes are closely associated with each other.Methods: We evaluated HCC hemodynamics by employing Sonazoid-enhanced ultrasound (SEUS) before surgical resection, and sought associations with histological grade and immunohistochemical staining of DCP in 19 areas from 11 patients.Results: In 10 HCC areas showing early washout (3 min ≥) using SEUS, three areas corresponded to poorly differentiated HCC and the remaining seven areas corresponded to moderately differentiated HCC, and positive DCP staining was observed in only two of the seven moderately differentiated HCC areas, whereas no staining was observed in poorly differentiated HCC areas. Six HCC areas showing intermediate washout (3-10 min) using SEUS were moderately differentiated, of which five demonstrated positive DCP staining (83.3%, 5/6). However, all HCC areas without enhancement in the arterial phase were well-differentiated and did not show DCP staining.Conclusion: Our preliminary findings suggest that HCC hemodynamics evaluated by SEUS are associated with histological grade and/or DCP production. [ABSTRACT FROM AUTHOR]

Purpose: To assess the diagnostic accuracy of contrast-enhanced ultrasound (CEUS), contrast-enhanced multiphase CT (CECT), and gadoxetic acid-enhanced MRI (EOB-MRI) in identifying residual tumor in the subacute follow-up of patients with malignant hepatic tumors treated by irreversible electroporation (IRE). Methods: We enrolled 16 patients with 21 hepatic lesions treated by IRE and examined by CEUS and CECT at 1 day after IRE and by EOB-MRI at 7 days after IRE. Follow-up examinations by EOB-MRI or CECT and CEUS were performed at 3-month intervals. Two radiologists independently reviewed the images and assessed the probability of residual tumor using a five-point scale with receiver operating characteristic (ROC) curve analysis. The sensitivity and specificity were also evaluated. Verifiable local recurrence was assessed using follow-up imaging as the reference standard. Results: The mean area under the ROC curve was significantly higher for CEUS (0.980) than for CECT (0.742, P < 0.01) and EOB-MRI (0.806, P < 0.01), as were the sensitivity and specificity (mean 85.7 and 85.7% for CEUS, respectively, vs 64.3 and 46.4% for CECT and 78.6 and 64.3% for EOB-MRI). Conclusion: CEUS was found to be superior to CECT and EOB-MRI for the diagnosis of residual tumor in the subacute phase following IRE. [ABSTRACT FROM AUTHOR]

Purpose: To determine the usefulness of arrival time parametric imaging (AtPI) using contrast-enhanced ultrasonography (CEUS) with Sonazoid in evaluating early response to sorafenib for hepatocellular carcinoma (HCC). Methods: Twenty-one advanced HCC patients with low α-fetoprotein (AFP) levels (≤35 ng/ml) who received sorafenib for at least 4 weeks were enrolled in this study. CEUS was performed before and 2 weeks after treatment, and the images of the target lesion in the arterial phase were analyzed by AtPI. In the color mapping images obtained by AtPI, the mean arrival time of the contrast agent in the target lesion from the reference point (mean time: MT) was calculated. In each patient, differences between MT before and MT 2 weeks after treatment were compared. MT (+) and MT (−) groups were defined as difference of 0 s or greater and less than 0 s, respectively. Overall survival was evaluated between the two groups. Results: In the MT (+) (11 patients) and MT (−) (10 patients) groups, the median survival time was 792 and 403 days, respectively, which was statistically significant. Conclusions: The results suggested that AtPI was useful for evaluating early response to sorafenib for advanced HCC with low AFP level. [ABSTRACT FROM AUTHOR]

Purpose: Using the low mechanical index (MI) contrast mode and the high MI contrast mode of contrast-enhanced ultrasonography, we evaluated which method is more sensitive for detecting Sonazoid microbubbles in the liver of normal subjects. Methods: Thirteen normal subjects received an intravenous bolus injection of 0.2 mL of Sonazoid. We defined the intensity difference as the intensity post-injection minus the intensity pre-injection. We evaluated the intensity difference at the portal vein using both the low MI (0.21-0.23) and the high MI (0.7-1.2) at 1 min, at every 10 min between 10 to 60 min, and at every 30 min between 60 to 300 min post-injection. The intensity difference at the liver parenchyma was also evaluated at eight points (1, 10, 30, 60, 120, 180, 240, and 300 min) using the low MI and at three points (1, 10, and 300 min) using the high MI. Results: The intensity differences at the portal vein measured using high MI were significantly higher than those measured using the low MI at each point between 1 and 240 min ( P < 0.01) and at 270 min post-injection ( P < 0.05). The intensity differences at the liver parenchyma measured using the high MI were also significantly higher than those measured using the low MI at each time point ( P < 0.01). Conclusion: Compared with the low MI, the high MI is more sensitive for detecting Sonazoid microbubbles in the liver of normal subjects. [ABSTRACT FROM AUTHOR]

Detection of reticuloendothelial system (RES) cells is essential for the differential diagnosis of splenic hamartoma. Among the imaging techniques using contrast agents phagocytosed by RES cells, contrast-enhanced ultrasonography (CEUS) with Sonazoid is less invasive and less costly than Tc-labeled colloid scintigraphy. We report a case of non-symptomatic splenic hamartoma in a 40-year-old woman detected as an abdominal tumor by screening ultrasonography. The tumor was 4 cm in diameter, round, slightly hypoechoic, and associated with a cystic lesion. The tumor region was stained on enhanced computed tomography with prolonged enhancement, while the cystic lesion was not. The mass appeared as mainly isointense with partial hyperintensity on T1-weighted and as a mixed hypo- and hyperintense region on T2-weighted magnetic resonance images. Tc-labeled colloid scintigraphy demonstrated uptake in only the tumor region. CEUS with Sonazoid revealed that the tumor was mainly hypervascular with non-enhanced areas in the early vascular phase, but the hypervascular region appeared also as a hyperechoic area (indicating microbubble phagocytosis) in the post-vascular phase. Thus, CEUS with Sonazoid revealed all three cardinal features of splenic hamartoma: hypervascularity, presence of RES cells, and tissue heterogeneity. Splenectomy and histopathology confirmed the presence of a splenic hamartoma with associated hematoma. CEUS with Sonazoid is a promising new diagnostic tool for splenic hamartoma. [ABSTRACT FROM AUTHOR]

Purpose: B-flow is a non-Doppler-based technology for visualizing blood flow and has a high spatial resolution. The aim of this study is to evaluate the blood flow information of liver tumors using B-flow in comparison with color Doppler sonography (CDS). Methods: Seventy-nine patients with 82 hepatic nodules were studied using B-flow and CDS. The study group included 45 HCC nodules, 23 liver metastasis nodules, four intrahepatic cholangiocarcinomas (ICC), and 13 hemangiomas. The visualized vascularity and morphological findings of the hepatic tumor vessel were evaluated. Results: B-flow showed multiple vessels in 48 nodules (58.5 %) and a single vessel in 13 nodules (15.9 %). CDS showed multiple vessels in 44 nodules (53.7 %) and a single vessel in 23 nodules (28.0 %). Multivariate analysis showed basket pattern was significant for HCC (OR 49.263; p = 0.0002), and penetrating vessel was significant for liver metastasis or ICC (OR 14.545; p < 0.0001). Conclusion: B-flow detects hepatic tumor blood flow with sensitivity as high as that of CDS. Vascular structure information obtained using B-flow could be potentially used to diagnose liver tumors. [ABSTRACT FROM AUTHOR]

Mucinous cystic neoplasms (MCNs) of the hepatobiliary system are rare tumors that usually arise within the liver. We encountered a 63-year-old woman with a surgically proven MCN of the liver. We first performed contrast-enhanced ultrasound imaging, and the mass was found to have the appearance of a solid tumor, showing peripheral nodular enhancement in the arterial and portal phases with persistence of enhancement. The lesion remained enhanced in the post-vascular phase (Kupffer phase). Based on these findings, we incorrectly identified the tumor as a cavernous hemangioma, despite negative findings in computed tomography and magnetic resonance imaging. In our immunohistologic analysis using anti-CD68 antibody, the antibody-positive cells were identified as macrophages. Therefore, the Sonazoid microbubbles could have been retained within these macrophages, resulting in late enhancement. These findings appear to be of key importance in accurately diagnosing MCNs and clarifying their pathophysiology. [ABSTRACT FROM AUTHOR]

Purpose: To compare sonazoid-enhanced ultrasound (SEUS) and contrast-enhanced computed tomography (CECT) enhancement and washout patterns in hepatic lesions. Methods: Enhancement and washout patterns on SEUS were compared with those on CECT for 61 lesions. There were 36 hepatocellular carcinomas, three intrahepatic cholangiocarcinomas, three metastatic lesions, eight focal nodular hyperplasias, two angiomyolipomas, and nine undetermined benign lesions. Diagnosis was based on histopathology, or CECT and tumor markers, or findings on 2-year follow-up. Results: All 61 lesions (100%) showed arterial enhancement on both SEUS and CECT. The 'washout/no washout' agreement between SEUS and CECT for the 61 lesions was 93.4% ( κ coefficient: 0.816). Of the 42 malignant lesions, 38 lesions (90.5%) showed washout on both SEUS and CECT. The remaining four malignant lesions, of which three lesions contained fibrosis (two intrahepatic cholangiocarcinomas and one scirrhous hepatocellular carcinoma), showed washout on SEUS but not on CECT. For the 19 benign lesions, agreement between SEUS and CECT was 100% ( κ coefficient: 1), with seven lesions showing washout with both methods and 12 lesions showing no washout with both methods. Conclusion: The overall concordance rate between SEUS and CECT was good, but some differences were seen in the washout patterns of malignant lesions. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to assess the characteristic features of hemodynamic changes in portal venous hypertension with spleno-renal shunt on conventional B-mode and color Doppler imaging before and after the Valsalva maneuver. Materials and methods: A total of 11 patients with portal venous hypertension underwent conventional B-mode and color Doppler ultrasound during follow-up examinations. Sonographic imaging of the splenic vein and the left renal vein was performed before and after the Valsalva maneuver. Results: In the six patients with spleno-renal shunt formation, dilated left renal veins were depicted after the Valsalva maneuver. In the five patients without spleno-renal shunt, there was no apparent dilatation of the left renal vein either before or after the Valsalva maneuver. In all six patients with spleno-renal shunt, color flow mapping of the left renal veins was emphasized during the Valsalva maneuver. In the five patients without spleno-renal shunt formation, there were no apparent changes on color flow mapping of the left renal vein before or after the Valsalva maneuver. Conclusion: The sonographic findings of the splenic vein and the left renal vein on conventional B-mode and color Doppler imaging before and after the Valsalva maneuver are useful for diagnosis of spleno-renal shunt and for grading the hemodynamic changes caused by spleno-renal shunt. [ABSTRACT FROM AUTHOR]

This review article provides an overview of the use of contrast-enhanced ultrasound (CEUS) in China. Currently, the only licensed contrast agent is SonoVue, a sulfur hexafluoride-filled microbubble contrast agent. In combination with a low mechanical index contrast-specific imaging mode, SonoVue-enhanced CEUS can be used to visualize the micro and macro-vasculature continuously. Since 2004, CEUS has been widely used in China in various clinical scenarios. The authors compared CEUS with baseline ultrasound or contrast-enhanced computed tomography with regard to characterization of focal liver lesions (FLLs). On CEUS, heterogeneous or homogeneous hyperenhancement during the arterial phase and washout in the portal/late phase are typical findings for hepatocellular carcinoma. The enhancement features of intrahepatic cholangiocarcinoma, infected FLLs, focal fatty infiltration, focal fatty sparing, complex cystic FLLs, and uncommon benign FLLs were carefully depicted. CEUS was also used for patient selection in ablation therapy and evaluation of response to ablation for liver cancer. The utility of three-dimensional CEUS of the liver was also explored. In non-liver use, CEUS in hilar cholangiocarcinoma, gallbladder, breast, and prostate was initially investigated. In addition, CEUS was used in interventional procedures such as CEUS-guided hemostatic injection, intraoperative CEUS in neurosurgery, and evaluation of response to high-intensity focused ultrasound ablation of uterine fibroids. The Chinese experience has resulted in increased use of CEUS. [ABSTRACT FROM AUTHOR]

The renal medullary microcirculation plays an important role in regulating sodium and water excretion, and its impairment is closely associated with various renal diseases. Contrast-enhanced ultrasonography (CEUS) using Sonazoid has not yet been reported as a method for evaluating the renal microcirculation; consequently, this study was carried out to reveal the characteristics of renal microcirculation using CEUS with Sonazoid. CEUS was performed on three healthy volunteers after they had fasted for at least 6 h. A GE LOGIQ7 ultrasound unit was used with a 2.0- to 5.5-MHz convex probe. Within approximately 1 min of intravenous injection of 0.0050 ml/kg Sonazoid, contrast images of the right kidney were acquired using a coded phase-inversion mode. Time-intensity curves were calculated for the cortex and medulla. Peak contrast intensity was significantly higher in the cortex (−56.4 ± 1.9 dB) than in the medulla (−66.7 ± 1.7 dB; P < 0.005). Peak times were significantly earlier in the cortex (17.4 ± 3.7 ms) than in the medulla (28.8 ± 6.3 ms; P < 0.05). CEUS using Sonazoid enables differentiation between the cortical and medullary microcirculation and is useful in clarifying renal pathophysiology and pharmacology. [ABSTRACT FROM AUTHOR]