How to characterize non-hypervascular hepatic nodules on contrast-enhanced computed tomography in chronic liver disease: feasibility of contrast-enhanced ultrasound with a microbubble contrast agent

Characterization of Early Hepatocellular Carcinoma and High-Grade Dysplastic Nodules on Contrast-Enhanced Ultrasound: Correlation With Histopathologic Findings

OBJECTIVES

To explore the enhancement features of early hepatocellular carcinoma (HCC, including well-differentiated HCC and high-grade dysplastic nodules with a focus of HCC) and high-grade dysplastic nodules (HGDNs) on contrast-enhanced ultrasound (CEUS), correlated with the histopathologic findings.

METHODS

This retrospective study enrolled 81 patients with 85 pathologically confirmed hepatic lesions (69 early HCCs and 16 HGDNs). All of the hepatic lesions were examined by CEUS with SonoVue (Bracco SpA, Milan, Italy) before surgery or biopsy. The enhancement features of early HCCs and HGDNs were evaluated and compared with histopathologic findings.

RESULTS

Thirty-eight (55.1%) early HCCs showed arterial-phase hyperenhancement (APHE). The major enhancement pattern of early HCCs was APHE without portal venous/late-phase wash-out (20 of 69 [29.0%]). Eight (11.6%) early HCCs manifested APHE. Wash-out was observed in 30 (43.5%) early HCCs. Sixteen (23.2%) early HCCs showed very-late wash-out (>120 seconds). Wash-out was not observed in all HGDNs. Of the 16 HGDNs, arterial-phase isoenhancement without portal venous/late-phase wash-out was the major enhancement pattern (n = 7 [43.8%]). The degree of CD34 expression of sinusoidal endothelial cells was more diffuse in early HCCs than in HGDNs (56.5% versus 12.5%; P = .001). Arterial-phase enhancement patterns of early HCCs on CEUS were correlated with the degree of CD34 expression (P = .039).

CONCLUSIONS

Enhancement patterns were significantly different between early HCCs and HGDNs on CEUS. Diffuse CD34 expression of sinusoidal endothelial cells in early HCC was correlated with APHE on CEUS.

Intensity-Based Assessment of Microbubble-Enhanced Ultrasonography: Phase-Related Diagnostic Ability for Cellular Differentiation of Hepatocellular Carcinoma

This prospective study aimed to elucidate the effect of phase-related quantitative parameters of contrast-enhanced ultrasound (CEUS) with perflubutane microbubble agent to assess the cellular differentiation of hepatocellular carcinoma (HCC). Intensity was analyzed in 94 lesions (19.4 ± 4.9 mm, 86 patients), 47 well-differentiated HCCs (wHCCs) and 47 moderately-differentiated HCCs (mHCCs): I(e) (early phase) = I(te) (tumor) - I(le) (liver), I(p) (post-vascular phase) = I(tp) (tumor) - I(lp) (liver), I(ep) = I(e) - I(p). The area under the receiver operating characteristic curve with the best cutoff value (I(e), 13.2, I(p), -4.5, I(ep), 21.3) for discriminating between wHCC and mHCC was 0.6922 for Ie, 0.7680 for Ip and 0.7925 for Iep, which indicated a significantly greater ability to differentiate between wHCC and mHCC compared with visual/qualitative assessment (early phase, 0.6170, p = 0.04; post-vascular phase, 0.6702, p = 0.01; both phases, 0.7021, p = 0.04). In conclusion, I(ep) was found to have the highest diagnostic ability, suggesting it is a promising parameter for the cellular differentiation of HCCs with CEUS.

Contrast enhancement ultrasound application in focal liver lesions characterization: a retrospective study about guidelines application (SOCEUS-CEUS survey)

INTRODUCTION

The SOCEUS survey aims to evaluate how contrast-enhanced ultrasound (CEUS) is effectively used in the focal liver lesions characterization.

MATERIALS AND METHODS

In the survey were involved Verona, Brescia and Trieste Radiological Centers and Arezzo and Bologna Non-radiological Centers. Inclusion criteria were liver focal lesion detection at conventional ultrasound and studied by means of CEUS, with or without CT or MRI examinations, done previous or subsequent to CEUS.

RESULTS

1069 forms were collected. Patients with benign lesions, who did not undergo any other studies, were 255/561 (45.5 %). Among patients with diagnosis of hemangioma at CEUS, those who had no other investigations were 129/267 (48.3 %). Patients with malignant lesions who had studies pre-CEUS (CT and/or MRI) were 328/508 (65 %), whereas those who had examinations post-CEUS (CT and/or MRI) were 218/508 (42.9 %). Concordance rate between CEUS and CT investigations pre- and post-CEUS was, respectively, 66 and 89 %. Concordance rate between CEUS and MRI studies pre- and post-CEUS was, respectively, 87.5 and 81.5 %.

CONCLUSION

This study proves contrast-enhanced ultrasound correct application in the involved centers.

Characterization of hepatic lesions (≤ 30 mm) with liver-specific contrast agents: a comparison between ultrasound and magnetic resonance imaging

PURPOSE

Imaging-based differentiation of hepatic lesions (≤ 30 mm) between well-differentiated hepatocellular carcinomas (w-HCC) and regenerative nodules (RN) presents difficulties. The aim was to compare the diagnostic abilities to differentiate w-HCC from RN using contrast-enhanced ultrasound and magnetic resonance imaging (MRI) both with liver-specific contrast agents.

MATERIALS AND METHODS

This prospective study included 67 pathologically proven hepatic lesions (17.5 ± 5.4mm, 54 w-HCCs, 13 RNs) in 56 patients with chronic hepatitis/cirrhosis (male 40, female 16; 29-79y). Hepatic-arterial/liver-specific phase enhancements were assessed quantitatively by ultrasound with perflubutane microbubble agent and MRI with gadolinium-ethoxybenzyl-diethylenetriamine with respect to the histological findings.

RESULTS

Sensitivity, specificity and accuracy of hepatic-arterial phase hyper-enhancement for w-HCC were 59.3%, 100% and 67.2% by ultrasound and 46.3%, 100% and 56.7% by MRI without significant difference. Meanwhile, those of liver-specific-phase hypo-enhancement for w-HCC were 44.4%, 100% and 55.2% by ultrasound and 87.0% (p<0.0001), 46.2% (p=0.0052) and 79.1% (p=0.0032) by MRI. Diagnostic accuracies for w-HCC by area under the receiver operating characteristic curves were higher in the hepatic-arterial phase in ultrasound (0.8316) than MRI (0.6659, p=0.0101) and similar in the liver-specific phase in ultrasound (0.7225) and MRI (0.7347, p=0.8814).

CONCLUSIONS

Hypervascularity is a significant feature which distinguishes w-HCC from RN, and ultrasound exerts a beneficial impact better than MRI for such characterization. However, both imaging have comparable abilities in the characterization of non-hypervascular lesions, compensating mutually for the poor sensitivity of ultrasound and the poor specificity of MRI in the liver-specific phase.

Heterogeneity of microbubble accumulation: a novel approach to discriminate between well-differentiated hepatocellular carcinomas and regenerative nodules

This prospective study aimed to elucidate the possibility of differentiating well-differentiated hepatocellular carcinoma (wHCC) from regenerative nodule (RN) on the basis of the heterogeneity of microbubble accumulation. Intensity analysis was conducted on early-phase and late-phase (60 s and 900 s post-injection; perflubutane microbubble) harmonic sonograms in 33 focal hepatic lesions (≤ 15 mm; 30 patients with chronic liver disease) that were histologically proven as wHCC or RN. Heterogeneity of enhancement, an average of standard deviation of late-phase enhancement in three different sections in the lesions with late-phase iso-enhancement, was examined with respect to the histologic findings. Heterogeneity of enhancement was higher in wHCC (28.7 ± 3.8) than RN (19.8 ± 2.1, p = 0.0213) in the 29 late-phase iso-enhancement lesions. The best cut-off value of the heterogeneity for the diagnosis of wHCC was 25.58, and the sensitivity and specificity were 77.8% and 100%, respectively. A novel parameter, heterogeneity of microbubble accumulation, facilitates differentiation between wHCC and RN showing a late-phase, iso-enhancement appearance.

Discrete hypoechoic ring in hepatic cavernous hemangioma resembling a malignant tumor: correlation with histologic features

Differential diagnoses of hepatic nodules include hepatocellular carcinoma, focal nodular hyperplasia, hepatic adenoma, regenerative nodule, focal fatty changes, and hemangioma. However, differentiation of these nodules can often be difficult. Hemangiomas are frequently encountered during ultrasonogram incidentally and can be diagnosed easily because they have an almost distinctive sonographic appearance: a homogeneous hyperechogenicity and discrete posterior acoustic enhancement. They also sometimes have atypical findings, for example an internal echogenicity including hypoechogenicity, heterogeneous echogenicity, hyperechoic rim, central hypoechogenicity due to various changes (e.g., internal hemorrhage, necrosis, thrombosis, myxomatous change, and fibrosis), and (rarely) calcification. We report herein the case of an atypical hemangioma presenting with a hypoechoic peripheral ring, mimicking a hepatic malignancy. To our knowledge, there have been no other reports demonstrating a cavernous hemangioma with a discrete hypoechoic ring and without a pseudocapsule.

Changes in tumor vascularity precede microbubble contrast accumulation deficit in the process of dedifferentiation of hepatocellular carcinoma

PURPOSE

To elucidate the changes in tumor vascularity and microbubble accumulation on contrast-enhanced sonograms, in relation to the dedifferentiation of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

This prospective study enrolled 10 patients with histologically proven HCC (14.4-39.0mm, 26.1+/-7.4) showing nodule-in-nodule appearance upon contrast-enhanced computed tomography. Contrast-enhanced ultrasound was performed by harmonic imaging under a low mechanical index (0.22-0.25) during the vascular phase (agent injection to 1 min) and late phase (15 min) following the injection of Sonazoid (0.0075 ml/kg). Contrast enhancement in the inner and outer nodules was assessed in comparison with that in adjacent liver parenchyma as hyper-, iso-, or hypo-enhanced.

RESULTS

Vascular-phase enhancement of all 10 inner nodules was hyper-enhanced, and that of outer nodules was hyper-enhanced in 3, iso-enhanced in 2, and hypo-enhanced in 5. Late-phase enhancement of inner nodules was hypo-enhanced in 8 and iso-enhanced in 2. Furthermore, late-phase enhancement of outer nodules was iso-enhanced in the 7 lesions that showed iso- or hypo-enhancement in the vascular phase, and hypo-enhanced in the 3 with hyper-enhancement in the vascular phase. Late-phase hypo-enhancement was significantly more frequent in the nodules showing early-phase hyper-enhancement (11/13) than in the nodules showing early-phase iso- or hypo-enhancement (0/7) in both the inner and outer nodules.

CONCLUSION

Dedifferentiation of HCC may be accompanied by changes in tumor vascularity prior to a reduction in microbubble accumulation. Observation of the vascular phase may be more useful than late-phase imaging for the early recognition of HCC dedifferentiation when using contrast-enhanced ultrasound with Sonazoid.