Contrast enhancement patterns of hepatic tumours during the vascular phase using coded harmonic imaging and Levovist to differentiate hepatocellular carcinoma from other focal lesions

Diagnostic value of contrast-enhanced ultrasound in hepatocellular carcinoma: a meta-analysis with evidence from 1998 to 2016

Background

This meta-analysis is aimed at determining the diagnostic value of hepatocellular carcinoma (HCC) with contrast-enhanced ultrasound (CEUS).

Materials and Methods

A comprehensive literature search of Pubmed, Web of Science, and the Cochrane Library was performed to identify published studies. The methodological quality of the included studies was evaluated. Data from eligible studies were used to estimate the pooled sensitivity, specificity, diagnostic odds ratio (DOR), positive and negative likelihood ratio (LR) and summary receiver operating characteristic (SROC) curve. Meta-Disc and STATA softwares were utilized for all statistical analyses.

Results

Fifty-three eligible studies (publication years ranged from 1998 to 2016) were selected according to inclusion criteria. The meta-analysis showed that the pooled sensitivity and specificity of CEUS to detect HCC were 0.85 (95% CI: 0.84–0.86) and 0.91 (95% CI: 0.90–0.92), respectively. The pooled positive and negative LRs were 6.28 (95% CI: 4.49–8.77) and 0.16 (95% CI: 0.12–0.22), respectively. The pooled DOR was 55.01 (95% CI: 35.25–83.47). The area under the SCOR curve was 0.9432. Meta-regression and funnel plot indicated that sample size, type of contrast agents and publication bias might be the major sources of heterogeneity.

Conclusions

CEUS is a valuable diagnostic tool for identifying HCC in clinic with highly sensitive and specific.

Utility of combined gray-scale and perflubutane contrast-enhanced ultrasound for diagnosing early hepatocellular carcinomas: Comparison of well differentiated and distinctly nodular types

AIM

To clarify the value of gray-scale ultrasound (US) combined with contrast-enhanced US (CEUS) with perflubutane in diagnosing early hepatocellular carcinoma (HCC).

METHODS

A total of 57 surgically resected, well differentiated HCCs were analyzed. Hepatocellular carcinomas were macroscopically diagnosed as vaguely nodular or distinctly nodular types, which correspond to early HCC or progressed HCC, respectively. Gray-scale US findings were evaluated in terms of shape (round or roundish, or irregular), border and contour (well-defined and smooth, or poorly defined), and intratumor echo levels (hyper, hypo, iso, heterogeneous, or mosaic). Contrast-enhanced US findings were evaluated during the arterial phase (vascularity [finely homogeneous, dendritic, or chaotic] and perfusion enhancement [homogeneous or heterogeneous]), portal phase (presence or absence of washout), and post-vascular phase (echo intensity level [defect, incomplete defect, or iso-enhancing]).

RESULTS

Eighteen HCCs were categorized as early HCCs and the remaining 39 were categorized as progressed HCCs. Receiver operating characteristic curve analysis for the diagnosis of early HCC yielded area under the receiver operating characteristic curve (A_z ) values for border and contour on gray-scale US and echo intensity level in the CEUS post-vascular phase of 0.782 and 0.828, respectively. Multiple logistic regression analysis also indicated that both of these gray-scale US and CEUS findings were independently associated with early HCC. The A_z value for the combination of border and contour and echo intensity for the diagnosis of early HCC was 0.907, corresponding to a high diagnostic value.

CONCLUSION

The combination of gray-scale US and CEUS can provide high-quality imaging assessment for diagnosing early HCC.

Utility of Contrast-enhanced Ultrasonography with Perflubutane for Determining Histologic Grade in Hepatocellular Carcinoma

The purpose of this study was to clarify the diagnostic value of contrast-enhanced ultrasonography (CEUS) with perflubutane in determining the histologic grade in hepatocellular carcinoma (HCC). A total of 147 surgically resected HCCs were dichotomized as well differentiated HCC (wd-HCC) and moderately- or poorly-differentiated HCC (mp-HCC). CEUS findings were evaluated during the arterial phase (vascularity, level and shape of enhancement), portal phase (presence or absence of washout) and post-vascular phase (echo intensity and shape). Receiver operating characteristic (ROC) curve analysis for the diagnosis of mp-HCC yielded area under the ROC curve (Az) values for arterial phase vascularity and portal phase washout of 0.910 and 0.807, respectively. The Az value for the combination of vascularity and washout for the diagnosis of mp-HCC was 0.956 (95% confidence interval, 0.910-0.979), corresponding to high diagnostic value. In conclusion, CEUS can provide high-quality imaging assessment for determining the histologic grade of HCCs.

Utility of contrast-enhanced ultrasound with perflubutane for diagnosing the macroscopic type of small nodular hepatocellular carcinomas

OBJECTIVE

To clarify the diagnostic value of contrast-enhanced ultrasound (CEUS) with perflubutane in the macroscopic classification of small nodular hepatocellular carcinomas (HCCs).

METHODS

A total of 99 surgically resected nodular HCCs with a maximum diameter of 3 cm or less were analysed. HCCs were macroscopically categorized as simple nodular (SN) and non-SN. CEUS findings were evaluated during the arterial phase (vascularity, level and shape of enhancement), portal phase (presence or absence of washout) and post-vascular phase (echo intensity and shape).

RESULTS

Sixty-eight HCCs were categorized as SN and the remaining 31 were categorized as non-SN. For diagnosis of non-SN HCC, the areas under the receiver operating characteristic curve (A z) value for the shape of enhancement in the late arterial phase and the shape of the post-vascular image were 0.824 (95 % confidence interval [CI] 0.721-0.895) and 0.878 (95 % CI 0.788-0.933), respectively. The A z value for the combination of the shape of enhancement in the late arterial phase and the shape of the post-vascular image for the diagnosis of non-SN HCC was 0.907 (95 % CI 0.815-0.956), corresponding to a high diagnostic value.

CONCLUSION

CEUS can provide high-quality imaging assessment for determining the macroscopic classification of small nodular HCCs.

KEY POINTS

• Non-SN is one of the poor prognostic factors in patients with HCC • Assessment of macroscopic type provides valuable information for the management of HCC • CEUS can provide high-quality imaging assessment for macroscopic classification of HCC • For non-SN HCC diagnosed using CEUS, hepatectomy is preferred as curative treatment.

The gross classification of hepatocellular carcinoma: usefulness of contrast-enhanced US

BACKGROUND

This study investigated the usefulness of postvascular images of contrast-enhanced ultrasonography (CE-US) in the gross classification of hepatocellular carcinoma (HCC) in comparison with contrast-enhanced CT (CE-CT) findings.

METHODS

This is a prospective study with consecutive HCC patients who had both CE-US and CE-CT prior to surgical resection. Fifty-one patients (32 men, 19 women; mean age, 68.9 years) with 61 HCCs were enrolled. The maximal diameters of all tumors ranged from 1.0 to 5.0 cm (mean ± SD, 2.5 cm ± 1.1). Weighted kappa statistics were used to assess the agreement of the sonographic or CT findings versus the results of macroscopic configurations.

RESULTS

Thirty-nine tumors were macroscopically diagnosed as simple nodule type; 19 tumors were macroscopically diagnosed as simple nodular type with extranodular growth, and 3 were macroscopically diagnosed as confluent multinodular type from the resected specimen. The diagnostic accuracy was 86.9% (53/61) for CE-US and 65.6% (40/61) for CE-CT. The differences in accuracy between CE-US and CE-CT were statistically significant (McNemar; p = 0.007). Agreement analysis between gross classification using CE-US and final macroscopic results gave a kappa value of 0.74 (95% CI: 0.65–0.82), which was considered a good agreement. On the other hand, kappa coefficient value was 0.38 (95% CI: 0.28–0.48) between gross classification using CE-CT and final macroscopic results.

CONCLUSIONS

CE-US is a more reliable tool than CE-CT to evaluate the gross type of HCC than CE-CT. Accurate gross classification using imaging is considered to be essential for the determination of the correct treatment strategy and the estimates of the patients' prognosis.

Current consensus and guidelines of contrast enhanced ultrasound for the characterization of focal liver lesions

The application of ultrasound contrast agents (UCAs) is considered essential when evaluating focal liver lesions (FLLs) using ultrasonography (US). Microbubble UCAs are easy to use and robust; their use poses no risk of nephrotoxicity and requires no ionizing radiation. The unique features of contrast enhanced US (CEUS) are not only noninvasiveness but also real-time assessing of liver perfusion throughout the vascular phases. The later feature has led to dramatic improvement in the diagnostic accuracy of US for detection and characterization of FLLs as well as the guidance to therapeutic procedures and evaluation of response to treatment. This article describes the current consensus and guidelines for the use of UCAs for the FLLs that are commonly encountered in US. After a brief description of the bases of different CEUS techniques, contrast-enhancement patterns of different types of benign and malignant FLLs and other clinical applications are described and discussed on the basis of our experience and the literature data.

Review of dynamic contrast-enhanced ultrasound guidance in ablation therapy for hepatocellular carcinoma

Local ablative techniques-percutaneous ethanol injection, microwave coagulation therapy and radiofrequency ablation (RFA)-have been developed to treat unresectable hepatocellular carcinoma (HCC). The success rate of percutaneous ablation therapy for HCC depends on correct targeting of the tumor via an imaging technique. However, probe insertion often is not completely accurate for small HCC nodules, which are poorly defined on conventional B-mode ultrasound (US) alone. Thus, multiple sessions of ablation therapy are frequently required in difficult cases. By means of two breakthroughs in US technology, harmonic imaging and the development of second-generation contrast agents, dynamic contrast-enhanced harmonic US imaging with an intravenous contrast agent can depict tumor vascularity sensitively and accurately, and is able to evaluate small hypervascular HCCs even when B-mode US cannot adequately characterize the tumors. Therefore, dynamic contrast-enhanced US can facilitate RFA electrode placement in hypervascular HCC, which is poorly depicted by B-mode US. The use of dynamic contrast-enhanced US guidance in ablation therapy for liver cancer is an efficient approach. Here, we present an overview of the current status of dynamic contrast-enhanced US-guided ablation therapy, and summarize the current indications and outcomes of reported clinical use in comparison with that of other modalities.

Primary squamous cell carcinoma of the liver: an uncommon finding in contrast-enhanced ultrasonography imaging

Primary squamous cell carcinoma (SCC) of the liver is rare tumor with an unfavorable prognosis. We report a case of advanced primary SCC of the liver arising adjacent to a nonparasitic liver cyst, invading into the right diaphragm and the right lung tissue. Contrast-enhanced ultrasonography (CE-US) demonstrated unique enhancement in the late vascular phase, which was incompatible with those observed in hepatocellular carcinoma, cholangiocellular carcinoma, or metastatic adenocarcinoma. The patient underwent surgical resection of the tumor followed by systemic chemotherapy with 5-fluorouracil (5-FU) and cisplatin (CDDP), while radiation chemotherapy was not applied because of relatively poor performance status. Although postoperative image analysis revealed no recurrence 4 months later, the patient died 13 months after the operation from recurrence. Immunohistological analysis of the resected specimen revealed that this SCC contained many capillary endothelial vessels expressing CD31 or CD34, possibly reflecting the unique imaging pattern in the late vascular phase of CE-US, which has been reported in choangiolocellular carcinoma. In addition, we reviewed which kind of treatment would be suitable for advanced hepatic primary SCC in the literature. From the review, it could be proposed that a combination of radiation therapy, systemic chemotherapy (5-FU and CDDP) and surgical resection, if possible, is appropriate for advanced primary SCC of the liver.

Contrast-enhanced ultrasound study of primary hepatic angiosarcoma: a pitfall of non-enhancement

OBJECTIVE

To investigate the contrast-enhanced ultrasound (CEUS) characteristics of primary hepatic angiosarcoma (PHA).

METHODS

The sonographic findings and CEUS images of PHA in three patients were retrospectively analyzed.

RESULTS

In our study, 3 cases of PHA (2 multiple nodules and 1 solitary mass) showed similar enhancement pattern on CEUS, characterized by remarkable central non-enhancement and peripheral irregular enhancement in the arterial and portal phase, and complete wash-out in the late phase. Furthermore, we unexpectedly found that abundant neoplastic tissues were present in the central area of non-enhancement on pathological evaluation. Based on literature review, we supposed that the unusual finding may be associated with the very low velocity of blood flow in the central region of tumors.

CONCLUSION

CEUS could well depict PHA with some common features, which may provide valuable clues in diagnosis of this rare disease. And non-necrotic tumor tissue of PHA could also demonstrate non-enhancement on CEUS, which warrant further investigations.

Hepatic malignancies: Correlation between sonographic findings and pathological features

Ultrasonography (US) findings are inevitably based on pathological features. Knowledge of the pathological features of hepatic malignancies such as hepatocellular carcinoma (HCC), liver metastasis and intrahepatic cholangiocarcinoma is essential for correct US diagnosis and appropriate management. One type of hepatocarcinogenesis is step-wise development from a low-grade dysplastic nodule (DN), high-grade DN, high-grade DN with malignant foci, and well-differentiated HCC, to classical HCC. The intranodular blood supply changes in accordance with this progression. Moreover, the malignant potential tends to change as the macroscopic configuration progresses. Therefore, typical US findings of advanced HCC are a mosaic pattern, septum formation, peripheral sonolucency (halo), lateral shadow produced by fibrotic pseudocapsule, posterior echo enhancement, arterial hypervascularity with dilated intratumoral blood sinusoids, and perinodular daughter nodule formation. Bull's eye appearance is a common presentation of metastases from gastrointestinal (GI) adenocarcinomas, and represents histological findings that show an area of central necrosis surrounded by a zonal area of viable tumor. Thick zonal area reflects the layer of viable cells that are fed by minute tumor vessels. US imaging features of liver metastases from the GI tract are as follows: Bull's eye appearance, multiple masses, irregular tumor border, arterial rim-like enhancement, and hypoenhancement in the late vascular phase. Most intrahepatic cholangiocarcinomas are ductal adenocarcinomas. The bile ducts peripheral to the tumor are usually dilated because of obstruction by tumors. US imaging features of mass-forming cholangiocarcinoma are as follows: peripheral bile duct dilatation, irregular tumor border, arterial enhancement due to minute intratumoral blood sinusoids, and hypoenhancement in the late vascular phase.

Intrahepatic cholangiocarcinoma and hepatocellular carcinoma: differential diagnosis with contrast-enhanced ultrasound

OBJECTIVE

We assessed the usefulness of contrast-enhanced ultrasound (CEUS) in the differentiation of intrahepatic cholangiocarcinoma (ICC) and hepatocellular carcinoma (HCC).

METHODS

The CEUS enhancement patterns of 50 ICCs were retrospectively analysed and compared with 50 HCCs. Two readers independently reviewed the baseline ultrasound (BUS) and CEUS images and the diagnostic performances were evaluated by receiver operating characteristic (ROC) analysis. Time-intensity curves (TIC) were plotted for quantification analysis.

RESULTS

In the arterial phase, peripheral rim-like hyperenhancement, heterogeneous hyperenhancement, homogeneous hyperenhancement and heterogeneous hypoenhancement were found in 25, 10, 3 and 12 of the ICCs versus 2, 29, 19 and 0 of the HCCs (P < 0.001), respectively. The diagnostic performance of both readers in terms of the area under the ROC curve (0.745 vs. 0.933 for reader 1, and 0.803 vs. 0.911 for reader 2), sensitivity (28% vs. 90%, and 44% vs. 82%) and accuracy (64% vs. 90%, and 71% vs. 90%) improved significantly after CEUS (all P < 0.05). The interobserver agreement increased from kappa = 0.575 at BUS to kappa = 0.720 after CEUS. TICs demonstrated that the intensities of the peripheral and central portions of the ICCs were lower than those of HCCs (both P < 0.05).

CONCLUSION

CEUS improves the diagnostic performance significantly in the differentiation between ICC and HCC.

Approach to a liver mass

Incidentally discovered liver masses are becoming more common with the increasing application and power of imaging techniques for the evaluation of abdominal conditions. Although such masses are often benign, conclusive diagnoses must be established in order to provide appropriate patient care. Various imaging modalities can be utilized to accurately diagnose such masses without resort to more invasive diagnostic measures.

Enhancement patterns of intrahepatic cholangiocarcinoma: comparison between contrast-enhanced ultrasound and contrast-enhanced CT

The aim of this study was to compare the enhancement pattern of intrahepatic cholangiocarcinoma (ICC) on contrast-enhanced ultrasound (CEUS) with that on contrast-enhanced computed tomography (CECT). 40 pathologically proven ICC lesions in 40 patients were evaluated retrospectively with both CEUS and CECT. The enhancement level and pattern in the dynamic phases on both CEUS and CECT were analysed. The diagnostic results of CEUS and CECT before pathological examination were also recorded. During arterial phases, the number of lesions that appeared as (i) peripheral irregular rim-like hyperenhancement, (ii) diffuse heterogeneous hyperenhancement, (iii) diffuse homogeneous hyperenhancement and (iv) diffuse heterogeneous hypoenhancement were 19 (47.5%), 9 (22.5%), 5 (12.5%) and 7 (17.5%), respectively, on CEUS, and 22 (55.0%), 3 (7.5%), 2 (5.0%) and 13 (32.5%), respectively, on CECT (p = 0.125). In the portal phase, the number of lesions showing hyperenhancement and hypoenhancement were 1 (2.5%) and 39 (97.5%), respectively, on CEUS, and 15 (37.5%) and 25 (62.5%) on CECT (p = 0.0001). CEUS made a correct diagnosis in 32 (80.0%) lesions before pathological examination; CECT made a correct diagnosis in 27 (67.5%) lesions (p = 0.18). In conclusion, the enhancement patterns of ICC on CEUS were consistent with those on CECT in the arterial phase, whereas in the portal phase ICC faded out more obviously on CEUS than on CECT. CEUS had the same accuracy as CECT in diagnosing ICCs, and so can be used as a new modality for the characterization of ICC.

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

BACKGROUND AND AIM

Although hypervascular appearance is characteristic in hepatocellular carcinoma (HCC), hepatic nodules without hypervascular appearance are sometimes found in patients with chronic liver disease (CLD). The aim of the present study was to clarify the efficacy of contrast-enhanced ultrasound (CEUS) with Levovist to characterize small, non-hypervascular hepatic nodules on contrast-enhanced computed tomography (CECT) in patients with CLD.

METHODS

The subject was 41 hepatic nodules (<30 mm, 18.5 +/- 5.6 mm) which showed non-hypervascular appearance on CECT in 35 patients with CLD; their histological results were 31 HCC (15 well, 14 moderate, and two poor) and 10 regenerative nodules (RN). CEUS with Levovist was performed under intermittent scanning (1-s interval) using APLIO at the early phase and the liver-specific phase, and the contrast enhancement of the nodule was assessed in comparison to that of the surrounding liver parenchyma. The contrast-enhanced findings with the time-intensity analysis were compared with the histological results.

RESULTS

Twelve nodules with weak enhancement in the liver-specific phase were HCC, regardless of their early-phase appearances. The other 29 nodules with equivalent or weak enhancement in the early phase and equivalent enhancement in the liver-specific phase were 19 HCC and 10 RN. Among them, the maximum-intensity ratio of tumor to non-tumor in the early phase was significantly higher in HCC than in RN (P < 0.01, n = 16), and the receiver-operating characteristic analysis showed a sensitivity of 1.0 and a specificity of 0.83 for their characterization.

CONCLUSION

CEUS with Levovist may be an alternative to biopsy to characterize small, non-hypervascular hepatic nodules on CECT in patients with CLD.

Primary hepatic malignant fibrous histiocytoma: clinicopathologic characteristics and prognostic value of ezrin expression

Primary hepatic malignant fibrous histiocytoma (MFH) is a rare entity with ill-defined clinicopathologic characteristics. We present the largest series to date (7 cases) of primary hepatic MFH, a systematic review of 27 cases published in the English literature, and an analysis of prognostic factors including ezrin expression. The 2 men and 5 women in our series were 34 to 80 years old (average 61 y) and presented with abdominal pain (6/7), systemic symptoms of low-grade fever, malaise, anorexia and weight loss (4/7), and spiking fever (1/7). One case was an incidental finding. Computed tomography and ultrasound revealed a well-demarcated solitary heterogeneous low-density mass ranging from 5.5 to 20 cm (average 12 cm) in largest dimension (5/7), or multiple small nodules up to 2 cm in diameter (1/7) or a 10 cm multiloculated cystic lesion owing to extensive necrosis (1/7). Histologically, a storiform-pleomorphic pattern with variable degrees of necrosis predominated (6/7). A myxoid pattern was seen in only 1 case and this case lacked necrosis. Lymphoplasmacytic infiltration was seen in 3/7 of the cases. Tumors were grade I (1/7), grade II (2/7), grade III (4/7), stage pT1 (4/7), pT2 (1/7), pT4 (1/7), and pT4, cM1 (1/7) at diagnosis. Three patients with tumor cell ezrin immunoreactivity score >or=1 died of tumor within 1 year. Two patients with tumor cell ezrin immunoreactivity score <1 survived >4 years after surgery. Combined analysis of our series and previously reported cases suggest that primary hepatic MFH possess certain characteristic clinicopathologic features that may help in making the diagnosis and in differentiating it from other more common neoplasms in the liver. The prognosis of hepatic MFH depends primarily on tumor size and stage at the time of diagnosis. Ezrin expression in tumor cells can provide additional prognostic information and may be a potential target for new adjuvant therapies.

[Diagnostic imaging of liver tumours. Current status]

Nowadays, contrast enhanced ultrasound (CEUS) is an imaging technique equivalent to multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) for the detection and characterization of focal liver lesions. These methods have comparable sensitivity and specificity in differentiating a liver lesion as "benign" or "malignant". For benign lesions, CEUS is the recommended method of the choice. In unclear cases, or if CEUS is not available, MRI or CT are the methods of the second choice. If a benign tumor remains unclear, then a needle biopsy is recommended. In the case of a malignant tumor, it is necessary to use a second imaging technique besides CEUS. In addition to the detection and characterization of a liver tumor, CT and MRI provide information on the extrahepatic spread of a tumor, particularly into the lung or retroperitoneum. The rapid development of surgical and interventional approaches requires accurate information on the character and number of malignant liver lesions. Therefore, the combined use of CEUS and MDCT or MRI currently represents the most modern and optimal standard of imaging. The standardization of CT and MRI protocols has increased the general diagnostic level of these images. Adequate training and a certificate for the use of CEUS is recommended in order to maintain the high diagnostic level of this method (EFSUMB guide lines). An optimal interdisciplinary imaging strategy for focal liver lesions minimises unnecessary invasive or potentially harmful imaging and reduces health costs.

Focal liver lesions: can SonoVue-enhanced ultrasound be used to differentiate malignant from benign lesions?

OBJECTIVE

To evaluate whether contrast-enhanced ultrasound (CEUS) with SonoVue could differentiate malignant focal liver lesions (FLLs) from benign lesions and provide lesion type diagnoses.

MATERIALS AND METHODS

Four hundred fifty-six patients with 554 FLLs were examined by CEUS with SonoVue using low mechanical index, nonlinear imaging techniques. Each lesion was characterized by 2 independent off-site readers as malignant or benign and given specific lesion type diagnosis, if possible, both at baseline ultrasound (US) and after SonoVue administration (CEUS). The final diagnosis was achieved by histopathology obtained from biopsy or surgical specimens, or by typical manifestation on contrast-enhanced CT or MRI.

RESULTS

The diagnostic accuracies of the 2 readers were 41.9% and 35.2% for baseline US, which improved significantly to 87.2% and 87.9% for CEUS (P < 0.05). Interreader agreement also increased with CEUS compared with baseline US (ê value changed from 0.49 to 0.77). The accuracy for lesion type diagnosis was 38.4% and 32.5% for baseline US, which increased to 77.6% and 78.0% for CEUS (P < 0.05).

CONCLUSIONS

CEUS with SonoVue improves differentiation between malignant and benign FLLs, and also provides improved lesion type (differential) diagnosis.

Terminology for contrast-enhanced sonography: a practical glossary

OBJECTIVE

The purpose of this glossary is to offer an updated guide to the correct terminology for contrast-enhanced sonography.

METHODS

This report was prepared by a panel of radiologists from the Sonography Section of the Italian Association of Medical Radiology. A leading author prepared a list of terms based on a comprehensive literature survey. The draft was analyzed by 3 experts on the topic of contrast-enhanced sonography. These reviewers reached a consensus and prepared the final version.

RESULTS

A list of 137 terms is included. These terms are briefly defined. Their proper application is discussed, with special reference to potential misleading uses.

CONCLUSIONS

Contrast-enhanced sonography is a relatively new diagnostic tool, now entering clinical practice in several countries. Use of appropriate, universal terminology is mandatory in the scientific setting to allow comparison between different published experiences. Additionally, use of clear, standardized terminology is necessary in the clinical setting to facilitate report understanding by the referring physician. Standardized, nonequivocal nomenclature may also help future diffusion of sonographic contrast media in countries where their application is still not approved.

Use of accumulation images obtained by arterial-phase contrast-enhanced harmonic grayscale ultrasonography to evaluate tumor vessels in focal nodular hyperplasia and other hepatic tumors

PURPOSE

To evaluate the usefulness of accumulation images obtained by arterial-phase contrast-enhanced harmonic grayscale ultrasonography for examining tumor vessels in focal nodular hyperplasia and other hepatic lesions.

METHODS

After injecting a galactose-palmitic acid contrast agent, we used conventional contrast-enhanced harmonic grayscale ultrasonography to scan 8 focal nodular hyperplasia lesions, 21 hepatocellular carcinomas, 2 cholangiocellular carcinomas, 12 hepatic metastases, 17 hemangiomas, and 2 angiomyolipomas. We then accumulated and superimposed consecutive conventional images (accumulation images) and compared them with corresponding conventional images to evaluate serial images of hepatic tumor vessels.

RESULTS

Serial tumor vessel findings obtained from accumulation images were superior to those obtained from conventional images in 51 (77%) of the 66 various hepatic lesions examined. Evidence of the spoke-wheel artery pattern in 2 of the 8 focal nodular hyperplasia lesions was equivocal in the conventional images, but accumulation images clearly depicted serial images of spoke-wheel arteries, clearly indicating a diagnosis of focal nodular hyperplasia. Accumulation images allowed the diagnosis of two additional focal nodular hyperplasia lesions that had not been correctly diagnosed as focal nodular hyperplasia from conventional images.

CONCLUSION

Accumulation images obtained by arterial-phase contrast-enhanced harmonic grayscale ultrasonography are useful in evaluating hepatic tumor vessels, especially spoke-wheel arteries, which specifically indicate focal nodular hyperplasia.

Recent applications of ultrasound: diagnosis and treatment of hepatocellular carcinoma

Ultrasound (US) has the advantages of real-time observation, simple technique, and a noninvasive procedure compared to other imaging modalities. The recent development of digital technologies has enabled the observation of sonograms with improved signal-to-noise ratio, penetration, and spatial and contrast resolutions. Furthermore, microbubble contrast agents have increased the diagnostic ability of US examination, and the use of three-dimensional sonograms is now not unusual. These advances have furthered the usefulness of US for liver tumors in clinical practice. This article reviews the recent applications of US in the diagnosis and treatment of hepatocellular carcinoma.

Real-time harmonic contrast material-specific US of focal liver lesions

Recent advances in contrast material-enhanced ultrasonography (US) mainly include (a) development of low-acoustic-pressure (low-mechanical-index) harmonic software, capable of obtaining real-time images without disrupting contrast material microbubbles, and (b) commercialization of new contrast media ("second-generation" contrast media), capable of producing intense echo signals in this low-mechanical-index setting. With use of low-mechanical-index continuous-mode contrast-enhanced US, the circulatory kinetic models of various focal liver lesions can be displayed dynamically. Hepatic lesions usually have typical perfusion characteristics and enhancement patterns through the various phases of parenchymal enhancement, which helps characterize lesions and, in most cases, allows definitive diagnosis, even among lesions that exhibit very similar baseline appearances. Because of the use of harmonic technologies at low emission frequencies, there is some loss of spatial resolution and overall image quality, typically resulting in a grainy appearance. In addition, lesion depth affects the detectability of vascularity to some degree in that poor signal arises from deep-seated lesions. Moreover, liver attenuation (eg, in patients with steatosis or chronic liver disease) further reduces the sensitivity of contrast-enhanced US. Nevertheless, with its unique capacity to provide images in real time, low-mechanical-index contrast-enhanced US is the dynamic imaging modality of choice in the differential diagnosis of focal liver lesions.

Evaluation of pathological features of hepatocellular carcinoma by contrast-enhanced ultrasonography: comparison with pathology on resected specimen

Features of hepatocellular carcinoma (HCC) observed by contrast-enhanced ultrasonography (CEUS) were compared to pathological features of corresponding resected HCC specimens, to evaluate the ability of CEUS to depict the pathological features of HCC. We investigated 50 HCC nodules that were treated by surgical resection. All nodules had been examined by CEUS with intravenous contrast agent (Levovist) before surgery. CEUS findings were divided into three phases for evaluation and classification of enhancement patterns: two vascular phases (arterial phase and portal venous phase) and the delayed phase. Pathological examination focused on differentiation and on the presence or absence of a tumor capsule, intratumoral septum, and intratumoral necrosis. All 21 nodules that showed a linear or annular vessel around the tumor margin in the arterial phase had capsular formation. Of the 27 nodules that showed heterogeneous perfusion in the portal venous phase, 21 (77.8%) had an intratumoral septum and 23 (85.2%) showed intratumoral necrosis. All nodules that were depicted as a defect with an unclear margin in the delayed phase were well-differentiated HCCs, whereas all nodules that were depicted as a defect with a clear margin were moderately or poorly differentiated HCCs. From our observations, the arterial, portal venous, and delayed phases of CEUS could reflect different pathological aspects of HCC. Some pathological characteristics of HCC might be evaluated preoperatively and non-invasively, by means of combined analysis of three phases of CEUS findings.

Imaging of peripheral cholangiocarcinoma with low-mechanical index contrast-enhanced sonography and SonoVue: initial experience

OBJECTIVE

The purpose of this study was to investigate the imaging findings of peripheral cholangiocarcinoma with low-mechanical index (MI) contrast-enhanced sonography.

METHODS

Eighteen nodules of peripheral cholangiocarcinoma proved by pathologic examination in 18 patients were evaluated with contrast-enhanced sonography. A low-MI real-time contrast-enhanced sonographic mode (ie, contrast pulse sequencing) and a sulfur hexafluoride-filled microbubble contrast agent (SonoVue [BR1]; Bracco SpA, Milan, Italy) were used.

RESULTS

On contrast-enhanced sonographic images, all 18 nodules (100%) of peripheral cholangiocarcinoma showed inhomogeneous enhancement during the arterial phase, and the emergence of nodule enhancement was earlier in 3 nodules (16.7%), simultaneous in 13 (72.2%), and later in 2 (11.1%), respectively, when compared with the adjacent liver tissue. During the arterial phase, 8 nodules (44.4%) showed irregular peripheral rimlike hyperenhancement, 2 (11.1%) showed inhomogeneous hyperenhancement, and 8 (44.4%) showed inhomogeneous hypoenhancement. In portal and late phases, all 18 nodules (100%) showed hypoenhancement. When contrast-enhanced sonography was added for analysis, the confidence levels of the investigators were improved in 15 (83.3%) of 18 nodules, and 17 (94.4%) of 18 peripheral cholangiocarcinomas were correctly characterized.

CONCLUSIONS

The imaging findings of peripheral cholangiocarcinoma had some characteristics on low-MI contrast-enhanced sonography. Knowledge of these characteristics might be beneficial for improving the diagnostic performance of sonography in evaluating this entity.

Foot pedal-activated injector for contrast-enhanced sonography

We assessed the feasibility and convenience of an injector that is electrically activated by a foot pedal for contrast-enhanced sonography. Thirty-seven patients with liver lesions underwent contrast-enhanced sonography using an injector that is activated by a foot pedal. The contrast agent was injected by pressing the foot pedal. All the studies were successfully performed without complications. The device enables the sonologist to keep the probe stationary during the injection and avoids the need for additional personnel. Pedal activated injection is a safe, useful, and convenient method of contrast-enhanced sonography.

Prediction of the ablated area by the spread of microbubbles during radiofrequency ablation of hepatocellular carcinoma

BACKGROUND/AIM

Radiofrequency ablation (RFA) is effective for the treatment of hepatocellular carcinoma (HCC). To prevent the ablation of adjacent organs and vessels, the spread of microbubbles generated by heating during RFA was observed by ultrasonography (US) and used to predict the ablated area; however, several reports documented that discrepancies existed between the spread of microbubbles and the ablated area.

PATIENTS AND METHODS

The spread of microbubbles during RFA was observed by US in 24 patients with HCC and the areas were compared with the defect of enhancement in contrast enhanced (CE)-US, using Levovist in the same plane.

RESULTS

During the ablation, the posterior margin was obscure but the border could be visualized 5 min after the ablation. The size of the area of hyperechogenicity 5 min after ablation and that of the defect observed by CE-US was found to correlate (r(2)=0.91, P<0.0001). The shape of the hyperechogenicity corresponded well to the defect area, even in cases showing irregular spread of the microbubbles.

CONCLUSION

The observation of microbubbles during RFA can predict the ablated area and might be useful to prevent the unfavorable ablation of adjacent organs and vessels.

[Contrast ultrasound imaging in focal liver lesions: diagnostic value and guidelines]

The recent introduction of high quality scanners and contrast agents for ultrasound deeply modifies diagnosis strategy in focal liver lesions by using validated criteria. Non-linear imaging methods using low mechanical index (MI<0.2) and second generation contrast agents allow real-time continuous imaging with concomitant limitation in background tIssue signal and also in agent collapse for a high quality contrast imaging giving dramatic improvement in detection and characterization of lesions. Interpretation is based on the presence of contrast agent within the lesion or not (hyper-, hypo- or isosignal) and the delay after injection (arterial, portal or parenchymal or late phase) as previously used by non-ultrasound methods. This allows an easy differentiation of benign from malignant lesions. Moreover, this allows complete characterization in 85 to 95% of all focal liver lesions and 75% in hepatocellular carcinomas. Those results markedly improve ultrasound accuracy compared to conventional sonography and so put contrast-enhanced sonography among recommended non-invasive imaging methods for focal liver lesions with changes in diagnostic strategy according to the lesion type and actual place of US methods. It is recommended to use contrast ultrasound methods in cancer staging for an optimal detection of liver metastases as well as in characterization of lesions detected during conventional sonography with a consecutive decrease of cost-diagnosis ratio.

Imaging the liver

Imaging of the liver is undertaken for the detection and characterization of suspected primary or secondary neoplasms, prior to planning a surgery or chemotherapy pump placement, for assessing treatment response, for evaluating biliary pathology, and for screening for liver neoplasms in high-risk groups. In this article, we review the advantages and disadvantages of various imaging modalities in the evaluation of the liver and formulate guidelines for the imaging of common clinical indications. A brief review of imaging findings in focal and diffuse liver disease is also presented.

CONTRAST HARMONIC ULTRASOUND OF SPONTANEOUS LIVER NODULES IN 32 DOGS

Thirty-two dogs with spontaneous hepatic nodules were given intravenous ultrasound contrast medium (Definity or Sonovue) and imaged with contrast harmonic software on a conventional ultrasound machine system. Digital video images were initially reviewed to describe the perfusion pattern of malignant nodules. The images were reviewed again to test this pattern against all individual nodules. Subjectively, there was improved conspicuity of malignant nodules after contrast enhancement compared with conventional imaging and increased numbers of malignant nodules were often noted. There was decreased conspicuity of benign nodules and no additional nodules were seen after contrast enhancement. There was a highly significant (P < 0.0001) association of malignancy with a hypoechoic nodule at surrounding normal liver peak contrast enhancement. Benign nodules were isoechoic to the surrounding normal liver at peak contrast enhancement. Only one benign nodule (hepatoma) had regions of hypoechogenicity compared with the surrounding normal liver at peak liver contrast enhancement. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were highly significant (P < 0.0001) (100%, 94.1%, 93.8%, 100%, and 96.9%, respectively). No complications or morbidity was noted throughout the course of the study. Contrast harmonic ultrasound appears to be accurate at discriminating between naturally occurring benign and malignant nodules in the liver of dogs.

[The role of contrast-enhanced ultrasonography for the detection of hepatocellular carcinoma]

The incidence of the hepatocellular carcinoma (HCC) is increasing in Occident, as well as in France. Primary prevention is the only solution for early detection. The combination of ultrasound (US) and alphaFP each 4 to 6 Months dosage has many limitations. The sensitivity of US examination is rather poor (less than 70% for lesions below 2 cm in diameter) and serum alphaFP values remain normal in almost 50% of HCC. US contrast agents (USCAs) with perfluorocarbon gases increase the backscattered signals during all phases of the liver transit, including arterial, portal and delayed phases. Hepatocellular lesions exhibit a specific kinetics with strong enhancement during arterial phase, and rapid wash-out during portal and delayed phases. USCAs increase the detection of HCCs and allow characterization of additional focal lesions found in cirrhotic livers (regenerative and dysplastic nodules, haemangiomas.). Indeed, regenerative nodules contrast uptake is synchronous to the surrounding parenchyma, and usually disappear during portal and delayed phases. However, US in cirrhosis remains a difficult examination, with limitations due to limited access to sub-diaphragmatic localization, attenuation of the ultrasound beam and shortness of the arterial phase.

Evaluation of contrast enhancement patterns in pancreatic tumors by coded harmonic sonographic imaging with a microbubble contrast agent

OBJECTIVE

The purpose of the study was to assess patterns of primary pancreatic lesions by contrast-enhanced sonography for differentiating ductal carcinomas from other pancreatic tumors.

METHODS

One hundred six consecutive patients with pancreatic masses, consisting of 83 ductal carcinomas, 7 endocrine carcinomas, 5 intraductal papillary mucinous tumors, 3 cases of autoimmune-related pancreatitis, 3 solid pseudopapillary tumors, 2 cases of chronic pancreatitis, 1 serous cystadenoma, 1 osteoclastoid giant cell tumor, and 1 follicular lymphoma, were examined by contrast-enhanced sonography with coded harmonic imaging in a phase inversion harmonic technique. The contrast enhancement patterns were assessed, and specimens removed during pancreatectomy were subjected to pathologic examination.

RESULTS

Internal tumoral vascularity was detected in 47 (56.6%) of the 83 ductal carcinomas. Vascular image spreading and homogeneous staining throughout the tumors were observed in all endocrine carcinomas. Two of the 5 intraductal papillary mucinous tumors were positive for enhancement effects. Enhancement effects were observed in all 3 cases of autoimmune-related pancreatitis, but the degree varied. There was a significant correlation between the intensity of enhancement effects and the ratio of patent vessels in the tumors (P < .05).

CONCLUSIONS

Vascularity was detected by contrast-enhanced sonography in only about half of the ductal carcinomas, confirming the difficulty in distinguishing those tumors from other pancreatic tumors. There was a correlation between the patency of the vessels in the tumors and their vascularity.