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Ultrasonography (US) has the overwhelming advantages of not entailing radiation exposure and being a noninvasive, real-time, convenient, easy-to-perform, and relatively inexpensive imaging modality. It is used as the first-line imaging modality for screening, detection, and diagnosis of focal liver lesions (FLLs) [small hepatocellular carcinomas (HCCs), in particular]. However, with the increasing demand for accurate and early diagnosis of small HCCs, newer radiologic methods need to be explored to overcome certain limitations of US. For example, the imaging is easily negatively affected by the presence of gas, rib cage, and subcutaneous fat, and is insensitive for capturing the subtle but vital information on the blood flow. It was in response to this need that new promising technologies such as contrast-enhanced ultrasound and fusion imaging were introduced for the detection of liver lesions. This paper presents an overview of the epidemiology and mechanisms of the development of HCCs, with an emphasis on the application of US in the diagnosis and treatment of FLLs. The aim of this article is to provide the state-of-the-art developments in the imaging diagnosis of FLLs and evaluation of ablation treatment of early HCCs. By keeping abreast of these recent advances, we hope that doctors and researchers working in the field of diagnosis/treatment of liver diseases will be able to discriminate benign FLLs such as regenerative nodules and focal nodular hyperplasia from HCCs, so as to avoid unnecessary repeated tumor biopsies and overtreatment. In particular, we expect that small HCCs or precancerous nodules (such as dysplastic nodules) can be accurately diagnosed and appropriately treated even at an early stage.

Purpose This study evaluated the usefulness of intraprocedural contrast-enhanced ultrasound (CEUS)/ultrasound (US) fusion imaging using a perflubutane-based contrast agent combined with preprocedural auto sweep three-dimensional US to obtain volume data for guidance and evaluation of the therapeutic efficacy of radiofrequency ablation (RFA). Methods This uncontrolled clinical trial included 50 hepatocellular carcinomas (HCCs) with a mean diameter of 15.3 mm that had been treated by RFA. The efficacy of RFA was evaluated by CEUS/US fusion imaging during the procedure. If the ablation was deemed to be inadequate, further ablation was performed until adequate ablation was achieved. Contrast-enhanced computed tomography (CECT) or contrast-enhanced magnetic resonance imaging (CEMRI) was performed a month after RFA, and the images obtained using each modality were reviewed to evaluate the efficacy of RFA. Results Thirty-three of the 50 lesions were evaluated by CEUS/US fusion imaging as having been adequately ablated after the first RFA procedure. The ablation was evaluated as inadequate in the remaining 17 lesions, for which additional ablation was performed. Ninety-eight (49/50) of all HCCs were evaluated as having been eventually adequately ablated on intraprocedural CEUS/US fusion imaging. The concordance rate for evaluations between intraprocedural CEUS/US fusion imaging and CECT/CEMRI performed 1 month after RFA was 88% (44/50). The kappa value for agreement between the two methods of evaluation was 0.792. Conclusion Intraprocedural fusion imaging combining CEUS and auto sweep three-dimensional US appears to be a useful modality for RFA guidance and evaluation of therapeutic efficacy of RFA in patients with HCC.

Background This study aimed to compare the value of Sonazoid contrast-enhanced ultrasound (SCEUS) with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid magnetic resonance imaging (EOB-MRI) for histological grading diagnosis, especially for early hepatocellular carcinoma (eHCC). Methods A total of 163 histopathologically confirmed HCC lesions were retrospectively collected, including 71 eHCCs (27 hypervascular, 44 non-hypervascular) and 92 advanced HCCs (adHCC) (73 hypervascular, 19 non-hypervascular). We performed SCEUS to evaluate the lesions' vascularity during the portal phase (PP) and the echogenicity during the post-vascular phase (PVP). EOB-MRI was used to determine the signal intensity between lesions and the surrounding liver parenchyma on unenhanced T1-weighted images (pre-contrast ratio) in the hepatobiliary phase (HBP) (post-contrast ratio). Results For the PP and PVP of SCEUS (for all lesions), the pre-and post-contrast ratios of EOB-MRI (for all hypervascular lesions) showed statistical differences in the diagnosis of some (but not all) histological grades. For the diagnosis of eHCC, isoechogenicity in the PVP achieved the best diagnostic efficacy [area under the receiver operating characteristic curve (AUC) =0.892]. Whether used independently or in a combination of any form, all indicators failed to produce a higher diagnostic efficacy than PVP. Post- (≥0.610) and pre-contrast ratios (≥0.981) yielded acceptable diagnostic efficacy, with, respectively, accuracy levels of 69.3% and 75.5% and AUC values of 0.719 and 0.736. For eHCC diagnosis, the post-contrast ratio (≥0.625) and combined diagnosis using pre- (≥0.907) and post-contrast ratios (≥0.609) revealed the highest sensitivity (92.6%) for hypervascular lesions and perfect specificity (100%) for non-hypervascular lesions. Conclusions Unenhanced T1-weighted images and the HBP of EOB-MRI [regardless of the vascularity in the arterial phase (AP)], and the PP and PVP of SCEUS showed their value in the histological grading diagnosis of HCC. In particular, isoechogenicity in the PVP may have promising diagnostic utility for eHCC.

OBJECTIVES We evaluated the detection rates for perfusion defects in hypervascular hepatocellular carcinomas comparing the low mechanical index (MI) and high MI contrast modes during the post-vascular phase (PVP) of contrast-enhanced ultrasonography. METHODS Seventy-eight patients with 84 hypervascular hepatocellular carcinomas (mean diameter, 23.4 ± 11.2 mm) were selected for this retrospective study. All the patients underwent whole-liver scanning using conventional ultrasonography before injection of a perflubutane-based contrast agent (Sonazoid), and all the detected nodules were classified as either hypoechoic or hyperechoic nodules. Next, hypoechoic and hyperechoic nodules were evaluated using contrast-enhanced ultrasonography, and the presence of a perfusion defect was assessed for each nodule using both the low MI (0.2-0.3) and the high MI (0.7-1.2) contrast modes during the PVP (10 minutes after injection). The data were analyzed using the McNemar test. RESULTS Forty-four nodules were classified as hypoechoic nodules, and the remaining 40 nodules were classified as hyperechoic nodules using conventional ultrasonography. The detection rate for perfusion defects determined using the high MI contrast mode was higher than that determined using the low MI contrast mode in hyperechoic nodules during the PVP (low MI, 58% [23 of 40]; high MI, 90% [36 of 40]; P

Radiotherapy is one of the available curative therapies for hepatocellular carcinoma (HCC). We investigate the use of contrast-enhanced ultrasound using Sonazoid (SCEUS) in evaluating the efficacy of radiotherapy for HCC. We enrolled 59 patients with 59 HCCs in this retrospective study. Tumor size and tumor vascularity were evaluated using SCEUS before and 1, 3, 7, 10, and 13 months after radiotherapy. The median follow-up period was 44.5 months (range: 16–82 months). Of the HCCs, 95% (56/59) had no local recurrence, while 5% (3/59) did. At 13 months after radiotherapy, in cases with no local recurrence, SCEUS showed a reduction in tumor vascularity in all cases, while tumor size reduction (>30% reduction, compared with pre-radiotherapy) was observed in 82.1% (46/56). In all three cases of local recurrence, vascularity and tumor size reduction were not observed during the follow-up period and residual HCCs were demonstrated pathologically. Compared with cases with local recurrence, tumor size reduction and reduction in tumor vascularity (p < 0.001) were significantly greater in cases with no local recurrence at 13 months after radiotherapy. SCEUS may be useful in evaluating radiotherapy efficacy for HCC.

To estimate the role of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced MRI (EOB-MRI) in predicting hypervascularization outcome of non-hypervascular hypointense hepatic lesions in high-risk patients for hepatocellular carcinoma (HCC). Under the premise of non-hyperenhance in arterial phase (AP) and hypointensity in hepatobiliary phase (HBP) of EOB-MRI, 29 fresh lesions from 22 patients with chronic viral hepatitis (median (range) age: 69(57–82) years) were prospectively enrolled. During continuously followed-up by EOB-MRI, lesional vascularity in AP, the signal intensity (SI) ratios of lesions-to-parenchyma in HBP images (post-contrast ratio) and adjusted enhancement with reference of unenhanced images (EOB enhancement ratio) were examined. After 644 (220–2912) days of follow-up, 20 lesions changed into hyperenhancement in AP of EOB-MRI (hypervascularized group), while nine remained non-hyperenhanced (maintained non-hypervascular group). There is no statistical difference of post-contrast ratio at the initial detection. The post-contrast ratios in hypervascularized group were different between each follow-up time point when followed-up ≥ three (P

Background & aims To explore the ability of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid magnetic resonance imaging (EOB-MRI)/ultrasound (US) fusion imaging (FI) to improve the prognosis of radiofrequency ablation (RFA) by ablating the characteristic findings of hepatocellular carcinoma (HCC) in hepatobiliary phase (HBP) imaging. Methods We retrospectively recruited 115 solitary HCC lesions with size of (15.9 ± 4.6) mm. They were all treated by RFA and preoperative EOB-MRI. According to the modalities guiding RFA performance, the lesions were grouped into contrast enhanced US (CEUS)/US guidance group and EOB-MRI/US FI guidance group. For the latter group, the ablation scope was set to cover the HBP findings (peritumoral hypointensity and irregular protruding margin). The presence of HBP findings, the modalities guided RFA, the recurrence rate were observed. Results After an average follow-up of 377 days, local tumor progression (LTP) and intrahepatic distant recurrence (IDR) were 14.8% and 38.4%, respectively. The lesions having HBP findings exhibited a higher recurrence rate (73.7%) than the lesions without HBP findings (42.9%) (p = 0.002) and a low overall recurrence-free curve using the Kaplan-Meier method (p = 0.038). Using EOB-MRI/US FI as guidance, there was no difference in the recurrence rate between the groups with and without HBP findings (p = 0.799). In lesions with HBP findings, RFA guided by EOB-MRI/US FI (53.8%) produced a lower recurrence rate than CEUS/US (84.0%) (p = 0.045). Conclusions The intraprocedurally application of EOB-MRI/US FI to determine ablation scope according to HBP findings is feasible and beneficial for prognosis of RFA.

We attempted to establish an ultrasound (US) imaging-diagnostic system for histopathological grades of differentiation of hepatocellular carcinoma (HCC). We conducted a retrospective study of histopathologically confirmed 200 HCCs, classified as early (45 lesions), well- (31 lesions), moderately (68 lesions) or poorly differentiated (diff.) (56 lesions) HCCs. We performed grayscale US to estimate the presence/absence of halo and mosaic signs, Sonazoid contrast-enhanced US (CEUS) to determine vascularity (hypo/iso/hyper) of lesion in arterial and portal phase (PP), and echogenicity of lesion in post-vascular phase (PVP). All findings were of significance for the diagnosis of some (but not all) histological grades (p < 0.001–0.05). Combined findings with a relatively high diagnostic efficacy for early, poorly and moderately diff. HCC were a combination of absence of halo sign and isoechogenicity in PVP of CEUS (accuracy: 93.0%, AUC: 0.908), hypovascularity in PP (accuracy: 78.0%, area under the curve (AUC): 0.750), and a combination of isovascularity in PP and hypoechogenicity in PVP (accuracy: 75.0%, AUC: 0.739), respectively. On the other hand, neither any individual finding nor any combination of findings yielded an AUC of over 0.657 for the diagnosis of well-diff. HCC. Our study provides encouraging data on Sonazoid CEUS in the histological differential diagnosis of HCC, especially in early HCC, and the effectiveness of this imaging method should be further proved by prospective, large sample, multicenter studies.

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. 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. 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

We investigated the characteristic findings of regenerative nodules (RNs) for differentiating early hepatocellular carcinoma (HCC) from high-grade dysplastic nodules (HGDNs) using magnetic resonance imaging (MRI) with gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA; EOB-MRI) and contrast-enhanced ultrasonography (CEUS) in patients with chronic liver disease. Pathologically confirmed lesions (100 early HCCs, 7 HGDNs, and 20 RNs with a maximum diameter of more than 1 cm and mean maximal diameters of 15.5, 15.1, and 14.8 mm, respectively) were enrolled in this retrospective study. The signal intensities of these lesions during the hepatobiliary phase of EOB-MRI were investigated, and findings characteristic of RNs using this modality were also evaluated using CEUS. Ninety-eight of the 100 early HCCs that were hypo-intense (n = 95), iso-intense (n = 2), or hyper-intense (n = 1) and the seven HGDNs that were hypo-intense (n = 6) or hyper-intense (n = 1) during the hepatobiliary phase of EOB-MRI exhibited centripetal vessels during the arterial dominant phase of CEUS, although one early HCC that was hypo-intense exhibited both centrifugal and centripetal vessels. Eighteen of the 20 RNs and one early HCC that were hyper-intense with a small central hypo-intensity and the remaining two RNs that were hyper-intense on EOB-MRI exhibited centrifugal vessels during the arterial dominant phase of CEUS. The small central hypo-intense area corresponded to central vascular structures in the lesion, such as the hepatic artery and portal vein running from the center to the periphery, when viewed using CEUS. Central vascular structures may be a characteristic finding of RNs when observed during the hepatobiliary phase of EOB-MRI and the arterial dominant phase of CEUS.