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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.

Usefulness of early vascular phase images from contrast-enhanced ultrasonography using Sonazoid for the diagnosis of hypovascular hepatocellular carcinoma

AIM

This study aimed to evaluate the usefulness of early vascular phase images produced by contrast-enhanced ultrasonography (CE-US) with Sonazoid for the diagnosis of hypovascular hepatocellular carcinoma (HCC).

METHODS

Four hundred and seventeen patients with 674 hepatic nodules were evaluated using CE-US with Sonazoid between January 2007 and March 2010. Retrospective analysis was conducted on 49 histologically confirmed nodules showing hypovascularity relative to the surrounding liver tissue in the early vascular phase and no enhancement defect in the Kupffer phase of CE-US with Sonazoid. These nodules were classified according to early vascular phase image enhancement patterns as types I (largest avascular; avascular as a whole), II (second avascular; partially avascular), III (smallest avascular; not avascular, but faintly hypovascular relative to the surrounding liver) and IV (hypovascular as a whole with vessel-like structures passing inside nodules).

RESULTS

Among the 49 nodules, types I, II, III and IV were identified in 19 (38.8%), nine (18.4%), 15 (30.6%) and six (12.2%) cases, respectively. The proportion of tumorous nodules (well-differentiated HCC and high-grade dysplastic nodules) significantly decreased with a reduction of the avascular area (68.4% in the type I, 55.6% in the type II and 33.3% in the type III nodules; P < 0.05). All nodules demonstrating the type IV enhancement pattern were non-tumorous.

CONCLUSION

Based on the size of avascular area in the early vascular phase of CE-US with Sonazoid, we can predict the malignant potential of the nodules. CE-US with Sonazoid is very useful for evaluation of hypovascular hepatic nodules.

Diagnostic and therapeutic management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an increasing health problem, representing the second cause of cancer-related mortality worldwide. The major risk factor for HCC is cirrhosis. In developing countries, viral hepatitis represent the major risk factor, whereas in developed countries, the epidemic of obesity, diabetes and nonalcoholic steatohepatitis contribute to the observed increase in HCC incidence. Cirrhotic patients are recommended to undergo HCC surveillance by abdominal ultrasounds at 6-mo intervals. The current diagnostic algorithms for HCC rely on typical radiological hallmarks in dynamic contrast-enhanced imaging, while the use of α-fetoprotein as an independent tool for HCC surveillance is not recommended by current guidelines due to its low sensitivity and specificity. Early diagnosis is crucial for curative treatments. Surgical resection, radiofrequency ablation and liver transplantation are considered the cornerstones of curative therapy, while for patients with more advanced HCC recommended options include sorafenib and trans-arterial chemo-embolization. A multidisciplinary team, consisting of hepatologists, surgeons, radiologists, oncologists and pathologists, is fundamental for a correct management. In this paper, we review the diagnostic and therapeutic management of HCC, with a focus on the most recent evidences and recommendations from guidelines.

Recent Advances in Tumor Ablation for Hepatocellular Carcinoma

Image-guided tumor ablation for early stage hepatocellular carcinoma (HCC) is an accepted non-surgical treatment that provides excellent local tumor control and favorable survival benefit. This review summarizes the recent advances in tumor ablation for HCC. Diagnostic imaging and molecular biology of HCC has recently undergone marked improvements. Second-generation ultrasonography (US) contrast agents, new computed tomography (CT) techniques, and liver-specific contrast agents for magnetic resonance imaging (MRI) have enabled the early detection of smaller and inconspicuous HCC lesions. Various imaging-guidance tools that incorporate imaging-fusion between real-time US and CT/MRI, that are now common for percutaneous tumor ablation, have increased operator confidence in the accurate targeting of technically difficult tumors. In addition to radiofrequency ablation (RFA), various therapeutic modalities including microwave ablation, irreversible electroporation, and high-intensity focused ultrasound ablation have attracted attention as alternative energy sources for effective locoregional treatment of HCC. In addition, combined treatment with RFA and chemoembolization or molecular agents may be able to overcome the limitation of advanced or large tumors. Finally, understanding of the biological mechanisms and advances in therapy associated with tumor ablation will be important for successful tumor control. All these advances in tumor ablation for HCC will result in significant improvement in the prognosis of HCC patients. In this review, we primarily focus on recent advances in molecular tumor biology, diagnosis, imaging-guidance tools, and therapeutic modalities, and refer to the current status and future perspectives for tumor ablation for HCC.

Usefulness of contrast-enhanced ultrasonography using Sonazoid for the assessment of therapeutic response to percutaneous radiofrequency ablation for hepatocellular carcinoma

AIM

Accurate assessment of the coagulated area is imperative to achieve an excellent outcome from percutaneous radiofrequency ablation (PRFA) for the treatment of hepatocellular carcinoma (HCC). We evaluated the efficacy of contrast-enhanced ultrasonography (CEUS) with the contrast-enhancing agent Sonazoid for precisely assessing the therapeutic effect of PRFA for HCC.

METHODS

We enrolled 87 consecutive patients with solitary naïve HCC of less than 3 cm in diameter. PRFA treatment was performed with a 17-G cool-tip needle, and CEUS was performed to assess the ablative margin 3 h after the procedure, when the coagulated tumor outline was easiest to discern. The treatment was repeated until an ablative margin greater than 5 mm was confirmed. After CEUS assessment of the therapeutic response, the patients were followed to investigate local tumor recurrence.

RESULTS

In 78 patients (89.7%), the outline of the coagulated tumors could be recognized by ultrasonography, and CEUS assessment of the ablative margin was successful. The remaining nine patients were assessed by computed tomography. The 5-year cumulative survival rate after the assessment of the treatment response with CEUS was 58.4%, and the 4-year cumulative total recurrence rate was 72.3%. The 5-year cumulative local tumor recurrence rate was very low (2.3%).

CONCLUSION

The assessment with CEUS at 3 h after the PRFA procedure was successful in the majority of the patients, and it yielded a very low rate of local recurrence.

Combination guidance of contrast-enhanced US and fusion imaging in radiofrequency ablation for hepatocellular carcinoma with poor conspicuity on contrast-enhanced US/fusion imaging

PURPOSE

The purpose of this study was to evaluate the usefulness of the combination guidance of contrast-enhanced US (CEUS) and fusion imaging in radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) with poor conspicuity on B-mode US and CEUS/fusion imaging.

MATERIALS AND METHODS

We conducted a retrospective cohort study, which included 356 patients with 556 HCCs that were inconspicuous on B-mode US. A total of 192 patients with 344 HCCs, 123 patients with 155 HCCs, and 37 patients with 57 HCCs underwent RFA under CEUS guidance, fusion imaging guidance, and the combination of CEUS and fusion imaging guidance.

RESULTS

The average number of treatment sessions was 1.1 (range: 1-2) in the CEUS guidance group, 1.1 (range: 1-2) in the fusion imaging guidance group, and 1.1 (range: 1-3) in the combination of CEUS and fusion imaging guidance group. Treatment analysis did not reveal significantly more RFA treatment sessions in the combination guidance group than in the other groups (p = 0.97, Student's t test). During the follow-up period (1.1-85.3 months, mean ± SD, 43.2 ± 59.5), the 3-year local tumor progression rates were 4.9, 7.2, and 5.9% in the CEUS guidance group, the fusion imaging guidance group, and the combination guidance group, respectively (p = 0.84, log-rank test).

CONCLUSION

In spite of selection bias, session frequency and local tumor progression were not different under the combination guidance with CEUS and fusion imaging in RFA. The combination of fusion imaging and CEUS guidance in RFA therapy is an effective treatment for HCC with poor conspicuity on B-mode US and CEUS/fusion imaging.

New malignant grading system for hepatocellular carcinoma using the Sonazoid contrast agent for ultrasonography

BACKGROUND

The ultrasonography contrast agent Sonazoid provides parenchyma-specific contrast imaging (Kupffer imaging) based on its accumulation in Kupffer cells. This agent also facilitates imaging of the fine vascular architecture in tumors through maximum intensity projection (MIP). We examined the clinical utility of the malignancy grading system for hepatocellular carcinoma (HCC) using a combination of 2 different contrast-enhanced ultrasonography images.

METHODS

We studied 121 histologically confirmed cases of HCC (well-differentiated, 45; moderately differentiated, 70; poorly differentiated, 6). The results of Kupffer imaging were classified as (1) iso-echoic pattern or (2) hypo-echoic pattern. The MIP patterns produced were classified into one of the following categories: fine, tumor vessels were not clearly visualized and only fine vessels were visualized; vascular, tumor vessels were visualized clearly; irregular, tumor vessels were thick and irregular. Based on the combined assessment of Kupffer imaging and the MIP pattern, the samples were classified into 4 grades: Grade 1 (iso-fine/vascular), Grade 2 (hypo-fine), Grade 3 (hypo-vascular), and Grade 4 (hypo-irregular).

RESULTS

The distribution of moderately and poorly differentiated HCCs was as follows: Grade 1, 4 % (1/24); Grade 2, 52 % (15/29); Grade 3, 85 % (44/52); and Grade 4, 100 % (16/16). The grading system also predicted portal vein invasion in 72 resected HCCs: Grade 1, 0 % (0/4); Grade 2, 13 % (1/8); Grade 3, 23 % (11/48); and Grade 4, 67 % (8/12).

CONCLUSIONS

This new malignant grading system is useful for estimation of histological differentiation and portal vein invasion of HCC.

Changes of guidelines diagnosing hepatocellular carcinoma during the last ten-year period

Hepatocellular carcinoma (HCC) is the third most common cause of cancer deaths in the world. There have been many advances in the diagnosis of HCC during the last ten years, especially in the imaging techniques. The Korean Liver cancer study group (KLCSG), European Association for the Study of the Liver (EASL), American Association for the Study of Liver disease (AASLD), and Asian-Pacific Association for the Study of Liver (APASL) have made and changed the HCC guidelines with the advances in the imaging techniques and according to the results of the researches on HCC. We reviewed the changes of the imaging guidelines in HCC diagnosis according to the advances in the imaging techniques. Further studies will be necessary to resolve the controversies in the diagnosis of HCC smaller than 1 cm in size.

Assessment of arterial hypervascularity of hepatocellular carcinoma: comparison of contrast-enhanced US and gadoxetate disodium-enhanced MR imaging

OBJECTIVE

To compare contrast-enhanced (CE) ultrasound with gadoxetate disodium-enhanced magnetic resonance (MR) imaging in the assessment of arterial hypervascularity of hepatocellular carcinoma (HCC) and dysplastic nodule (DN), with CT during hepatic arteriography (CTHA) as the reference standard.

METHODS

This study included 54 consecutively diagnosed patients, with 57 histologically confirmed HCCs and 3 DNs (high-grade). All patients underwent CE ultrasound, gadoxetate disodium-enhanced MR imaging and CTHA. Two trained diagnostic radiologists interpreted the CTHA images and rated the degree of intratumoral arterial vascularity by consensus using a five-point confidence scale as the reference standard. In the observer study, the degrees of vascularity on CE ultrasound and gadoxetate disodium-enhanced MR images were qualitatively analysed by four independent readers using a five-point confidence scale. Diagnostic accuracy was analysed by receiver-operating characteristic (ROC) analysis.

RESULTS

The diagnostic accuracies of the average area under the ROC curve (AUC) were significantly greater with CE ultrasound (average AUC: 0.94; 95% confidence interval [CI]: 0.88-1.00) than with gadoxetate disodium-enhanced MR imaging (average AUC 0.84, 95% CI 0.74-0.93, P = 0.0014).

CONCLUSION

Contrast-enhanced ultrasound yields a significantly higher AUC value than gadoxetate disodium-enhanced MR imaging in the assessment of arterial hypervascularity of HCC and DN.

KEY POINTS

• Arterial hypervascularity is an important feature determining treatment options in hepatocellular carcinoma. • It can be assessed by contrast-enhanced (CE) ultrasound or magnetic resonance (MR) imaging. • CE ultrasound was more accurate than Gd-EOB-DTPA MRI in assessing intratumoral vascularity. • Hypovascular hepatic nodules should be further investigated using CE ultrasound.

Diagnostic imaging of hepatocellular carcinoma: recent progress

The diagnostic imaging of hepatocellular carcinoma (HCC) has recently undergone marked progress. The advent of the ultrasound (US) contrast agent Sonazoid, approved in January 2007, and magnetic resonance imaging (MRI) with the liver-specific MRI contrast agent gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA-MRI), approved in January 2008, are of particular significance. Sonazoid contrast-enhanced US (Sonazoid-CEUS) is useful not only for the diagnosis of HCC, but also for guiding treatment and assessing treatment response. Sonazoid-CEUS has proven to be particularly effective for screening and staging, which used to be considered impossible with CEUS, through the introduction of the newly developed diagnostic technique of defect reperfusion imaging. It is still not possible if other vascular agents such as SonoVue and Definity are used. In particular, Gd-EOB-DTPA-MRI has been suggested to be much more reliable in the differentiation of early HCC from precancerous dysplastic nodules than any other modalities such as multidetector raw computed tomography, dynamic MRI, and superparamagnetic iron oxide-MRI. A decrease in contrast uptake in the hepatocyte phase observed on EOB-MRI is strongly suggestive of cancer, and the absence of early staining in the arterial phase suggests early HCC. The differential diagnostic capacity of Gd-EOB-DTPA-MRI is considered to far exceed that of what were previously the most useful imaging techniques, computed tomography (CT) during hepatic arteriography or CT during arterial portography, and to be comparable to that of the pathological diagnosis by pathologists specialized in liver.

Biologic and clinical features of benign solid and cystic lesions of the liver

The widespread use of imaging analyses, either routinely or to evaluate symptomatic patients, has increased the detection of liver lesions (tumors and cysts) in otherwise healthy individuals. Although some of these incidentally discovered masses are malignant, most are benign and must be included in the differential diagnosis. The management of benign hepatic tumors ranges from conservative to aggressive, depending on the nature of the lesions. New imaging modalities, increased experience of radiologists, improved definition of radiologic characteristics, and a better understanding of the clinical features of these lesions have increased the accuracy of diagnoses and reduced the need for invasive diagnostic tests. These advances have led to constant adjustments in management approaches to benign hepatic lesions. We review the biologic and clinical features of some common hepatic lesions, to guide diagnosis and management strategies.

Diagnostic accuracy of contrast-enhanced ultrasound in differentiating benign and malignant focal liver lesions: a retrospective study

PURPOSE

The purpose of this study was to assess the diagnostic accuracy of our early experience with contrast-enhanced ultrasound (CEUS) in the characterisation of focal liver lesions (FLLs) using histopathology, contrast-enhanced computed tomography (CT), magnetic resonance imaging (MRI) or other imaging follow-up as the standard of reference.

MATERIALS AND METHODS

Seventy-three patients with 82 FLLs who underwent liver CEUS from January 2006 to December 2008 were retrospectively reviewed. CEUS was performed with up to 4.8 mL of SonoVue® (Bracco, Milan, Italy) using a low mechanical index mode. The CEUS findings were compared with histopathology, or where histopathology was not available, clinical and imaging follow-up over at least 12 months was used as the standard of reference.

RESULTS

Of the 82 FLLs, 50 were malignant and 32 were benign at final diagnosis. CEUS correctly identified 43 malignant FLLs, with final diagnosis confirmed by histopathology in 13 lesions and clinico-radiological follow-up in 30 lesions. Twenty-nine lesions were correctly identified as benign on CEUS, with all these lesions confirmed on clinico-radiological follow-up. CEUS demonstrated a sensitivity of 86.0% and a specificity of 90.6% in the characterisation of liver lesions as malignant, with an overall accuracy of 87.8% (P < 0.05).

CONCLUSION

Our early experience has shown that CEUS can be accurate in differentiating malignant from benign FLLs and may become a useful first-line imaging tool where CT or MRI are not available or contra-indicated.

Estimation of malignant potential of GI stromal tumors by contrast-enhanced harmonic EUS (with videos)

BACKGROUND

Contrast-enhanced harmonic EUS (CEH-EUS) is a new sonographic technique that uses US contrast agents and depicts intratumoral vessels in real time.

OBJECTIVE

To evaluate whether assessment of tumor vascularity by CEH-EUS can predict the preoperative malignancy risk of GI stromal tumors (GISTs).

DESIGN

Prospective study to observe GIST vascularity.

SETTING

Kinki University School of Medicine.

PATIENTS

Between June 2007 and September 2009, 76 consecutive patients suspected of having subepithelial lesions underwent CEH-EUS.

INTERVENTION

CEH-EUS was performed by using a prototype echoendoscope in an extended pure harmonic detection mode.

MAIN OUTCOME MEASUREMENTS

Resected GIST specimens in 29 patients who underwent surgical resection were divided into high-grade (n=16) and low-grade (n=13) malignancy groups based on mitotic activity. The abilities of EUS-guided FNA and CEH-EUS to diagnose the malignant potential were compared. The sensitivities with which contrast-enhanced multidetector CT, power-Doppler EUS, and CEH-EUS detected intratumoral vessels in high-grade malignancy GISTs also were compared.

RESULTS

CEH-EUS identified irregular vessels and thereby predicted GIST malignancies with a sensitivity, specificity, and accuracy of 100%, 63%, and 83%, respectively. Diagnosis of high-grade malignancy GISTs by EUS-guided FNA had a sensitivity, specificity, and accuracy of 63%, 92%, and 81%, respectively. Contrast-enhanced multidetector CT, power-Doppler EUS, and CEH-EUS detected intratumoral vessels in high-grade malignancy GISTs with sensitivities of 31%, 63%, and 100%, respectively (P<.05).

LIMITATIONS

A single center was involved in this study.

CONCLUSIONS

CEH-EUS successfully visualized intratumoral vessels and may play an important role in predicting the malignancy risk of GISTs.

Contrast-enhanced 3D ultrasonography in minute hepatocellular carcinoma

PURPOSE

The study aimed to clarify whether contrast-enhanced (CE) three-dimensional (3D) ultrasonography (US) can depict characteristic hyperstain and washout patterns in minute nodules ≤10 mm of hepatocellular carcinoma (minute HCC), and whether it serves as a potent diagnostic modality.

METHODS

CE 3D US was carried out to depict hyperstain and washout of a solitary nodule ≤10 mm in patients with liver cirrhosis. When both patterns were depicted with success, CE computed tomography (CT) and CE magnetic resonance imaging (MRI) were also carried out as part of a comparative study, and then a histological specimen was obtained by needle biopsy. The final diagnosis was based on the histopathological findings and a follow-up on the growth of nodules.

RESULTS

All 12 minute nodules exhibiting hyperstain and washout showed evidence of HCC when examined by CE 3D US. The CE CT and CE MRI examinations could depict both of these patterns, characteristic of HCC, in most of the nodules but rather less successfully than CE 3D US.

CONCLUSION

CE 3D US can depict hyperstain and washout patterns in minute HCC and serves as a potent modality for diagnosis.

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.

Differentiation of focal liver lesions using three-dimensional ultrasonography: Retrospective and prospective studies

AIM: To differentiate focal liver lesions based on enhancement patterns using three-dimensional ultrasonography (3D US) with perflubutane-based contrast agent.

METHODS: Two hundred and eighty two patients with focal liver lesions, including 168 hepatocellular carcinomas (HCCs), 63 metastases, 40 hemangiomas and 11 focal nodular hyperplasias (FNHs), were examined by 3D US with perflubutane-based contrast agent. Tomographic ultrasound images and sonographic angiograms were reconstructed. Among 282 lesions, enhancement patterns of 163 lesions between January 2007 and October 2007 were analyzed retrospectively. Then from November 2007 to May 2008, compared with contrast-enhanced (CE) 2D US, CE 3D US was performed on 119 lesions for prospective differential diagnosis. Sensitivity, specificity, area under receiver operating characteristic curve (A_z) and inter-reader agreement were assessed.

RESULTS: With the tridimensional view, dominant enhancement patterns were revealed as diffuse enhancement or peripheral ring-like enhancement, followed with washout change for HCCs or metastases, respectively, and peripheral nodular enhancement or diffuse enhancement with spoke-wheel arteries, followed by persistent enhancement for hemangiomas or FNHs, respectively. At CE 3D US, the prospective differentiation of lesions showed sensitivity 92% (mean for two readers), specificity 91% and A_z value 0.95 for HCCs, 84%, 97%, and 0.95 for metastases, 91%, 98%, and 0.98 for hemangiomas and 80%, 99%, and 0.99 for FNHs, respectively, while good to excellent inter-reader agreement was achieved. No significant difference exists between prospective diagnosis accuracy at CE 3D US and that at CE 2D US.

CONCLUSION: CE 3D US provides a spatial perspective for liver tumor enhancement, and could help in differentiating focal liver lesions.

Hypervascular liver masses on contrast-enhanced ultrasound: the importance of washout

OBJECTIVE

The objective of our study was to determine the role of negative enhancement (washout), its presence and timing, in the differential diagnosis of hypervascular liver masses on contrast-enhanced ultrasound.

MATERIALS AND METHODS

One-hundred forty-six hypervascular liver lesions (mean size, 3.9 cm; range, 1.0-17.0 cm) were evaluated with contrast-enhanced ultrasound over a 6-month period. Seventy-four were benign (29 hemangiomas, 31 focal nodular hyperplasia [FNH] lesions, seven adenomas, five inflammatory lesions, two other) and 72, malignant (41 hepatocellular carcinomas [HCCs], 25 metastases, six other). Two independent reviewers retrospectively recorded the presence and timing of washout in the portal venous phase, observing until 4 minutes after injection, of a contrast agent (perflutren microspheres). Diagnoses were confirmed by histopathology (n = 68) or clinicoradiologic follow-up (n = 78). Timing of washout was compared between types of lesion using Fisher's exact test.

RESULTS

Washout occurred in both benign (27/74, 36%) and malignant (70/72, 97%) lesions but was more frequently seen in malignancy (p < 0.001) (kappa = 0.91). Metastases showed more rapid washout than HCCs (p < 0.001): 20 of 25 metastases showed washout by 30 seconds after injection and 23 of 41 HCCs, later than 75 seconds. All malignant lesions without washout were HCCs (2/41). Among the benign lesions, all five inflammatory lesions showed rapid washout before 75 seconds and six of seven adenomas showed washout, mostly later than 75 seconds (5/6). Washout also occurred in hemangiomas (6/29) and FNH lesions (9/31), mostly later than 75 seconds after injection (12/15).

CONCLUSION

Hypervascular malignant lesions show washout except infrequent cases of HCC. Rapid washout characterizes metastases, whereas HCCs show variable, often slow, washout. However, washout is not unique to malignancy and may be seen in benign lesions.

Characterization of focal liver lesions with contrast-enhanced ultrasound

The introduction of second generation microbubble ultrasound (US) contrast agents, such as SonoVue (Bracco, Milan, Italy), has considerably improved the diagnostic yield of US imaging for the evaluation of focal hepatic lesions in recent years because of its ability to very sensitively depict tumoral vascularity. In addition, contrast-enhanced US (CEUS) has the advantage of the absence of ionizing radiation, the widespread availability, even at the bedside, and the possibility to characterize a lesion as soon as detected on conventional B-mode US, commonly used as the first technique for exploration of the liver. The present review focuses on the basic principles of the technique and the various patterns of benign and malignant hepatic lesions at CEUS, contributing to their characterization. Understanding of these enhancement features at CEUS according to the type of tumors enables to make more accurate characterization of focal liver lesions as well as give better advice to oncologists, hepatologists or other clinicians in case of suspected liver tumors.

Asian Pacific Association for the Study of the Liver consensus recommendations on hepatocellular carcinoma

INTRODUCTION

The Asian Pacific Association for the Study of the Liver (APASL) convened an international working party on the management of hepatocellular carcinoma (HCC) in December 2008 to develop consensus recommendations.

METHODS

The working party consisted of expert hepatologist, hepatobiliary surgeon, radiologist, and oncologist from Asian-Pacific region, who were requested to make drafts prior to the consensus meeting held at Bali, Indonesia on 4 December 2008. The quality of existing evidence and strength of recommendations were ranked from 1 (highest) to 5 (lowest) and from A (strongest) to D (weakest), respectively, according to the Oxford system of evidence-based approach for developing the consensus statements.

RESULTS

Participants of the consensus meeting assessed the quality of cited studies and assigned grades to the recommendation statements. Finalized recommendations were presented at the fourth APASL single topic conference on viral-related HCC at Bali, Indonesia and approved by the participants of the conference.

Asian Pacific Association for the Study of the Liver consensus recommendations on hepatocellular carcinoma

INTRODUCTION

The Asian Pacific Association for the Study of the Liver (APASL) convened an international working party on the management of hepatocellular carcinoma (HCC) in December 2008 to develop consensus recommendations.

METHODS

The working party consisted of expert hepatologist, hepatobiliary surgeon, radiologist, and oncologist from Asian-Pacific region, who were requested to make drafts prior to the consensus meeting held at Bali, Indonesia on 4 December 2008. The quality of existing evidence and strength of recommendations were ranked from 1 (highest) to 5 (lowest) and from A (strongest) to D (weakest), respectively, according to the Oxford system of evidence-based approach for developing the consensus statements.

RESULTS

Participants of the consensus meeting assessed the quality of cited studies and assigned grades to the recommendation statements. Finalized recommendations were presented at the fourth APASL single topic conference on viral-related HCC at Bali, Indonesia and approved by the participants of the conference.

The 2008 Okuda lecture: Management of hepatocellular carcinoma: from surveillance to molecular targeted therapy

Hepatocellular carcinoma (HCC) is responsible for approximately 600,000-700,000 deaths worldwide. It is highly prevalent in the Asia-Pacific region and Africa, and is increasing in Western countries. Alpha fetoprotein (AFP) alone is insufficient for HCC screening. A combination with other tumor markers, such as PIVKA-II and AFP-L3, and periodical ultrasound surveillance is necessary. Sensitivity of AFP in depicting HCC is highest, followed by PIVKA-II and AFP-L3, but the order of the specificity is inverse, AFP-L3, PIVKA-II, and AFP. Sonazoid-enhanced ultrasound (US) is extremely useful to characterize hepatic tumors equal to or more than multidetector row computed tomography (MDCT). Sonazoid-enhanced US with defect re-perfusion imaging is a breakthrough technique in the treatment of HCC. Defect re-perfusion imaging will markedly change the therapeutic strategy for liver cancer. Gd-EOB-DTPA-magnetic resonance imaging is a newly developed imaging technique in the detection and diagnosis of HCC. It is the most sensitive tool in the differentiation of early HCC from dysplastic nodules. Regarding the treatment strategy, there has been no established systemic chemotherapy for advanced HCC, except for Sorafenib. Empirically, intrahepatic arterial infusion chemotherapy using implanted reservoir port is known to be effective in response rate and overall survival for advanced HCC with vascular invasion. Sorafenib in combination with transcatheter arterial chemoembolization or adjuvant use after ablation or resection will significantly prolong the life expectancy if ongoing clinical trials provide positive results. In conclusion, it is expected that readers will gain deeper insight into the latest progress and updated diagnosis and treatment of HCC described in this review.

Effect of observer experience in the differentiation between benign and malignant liver tumors after ultrasound contrast agent injection

OBJECTIVE

The purpose of this study was to assess the impact of the observer level of experience on the diagnostic performance of contrast-enhanced ultrasound imaging (CEUS) for differentiation between benign and malignant liver tumors.

METHODS

From a computerized search, we retrospectively identified 286 biopsy-proven liver tumors (105 hepatocellular carcinomas, 48 metastases, 7 intra-hepatic cholangiocarcinomas, 33 liver hemangiomas, and 93 nonhemangiomatous benign lesions) in 235 patients (140 male and 95 female; mean age +/- SD, 56 +/- 11 years) who underwent CEUS after sulfur hexafluoride-filled microbubble injection. The digital cine clips recorded during the arterial (10-35 seconds from injection), portal (50-120 seconds), and late (130-300 seconds) phases were analyzed by 6 independent observers without experience (group 1, observers 1-3) or with 2 to 10 years of experience in CEUS (group 2, observers 4-6). Specific training in the diagnostic and interpretative criteria was provided to the inexperienced observers. Each observer used a 5-point scale to grade diagnostic confidence: 1, definitely benign; 2, probably benign; 3, indeterminate; 4, probably malignant; or 5, definitely malignant on the basis of the enhancement pattern during the arterial phase and enhancement degree during the portal and late phases compared with the liver (hypoenhancement indicating malignant and isoenhancement to hyperenhancement indicating benign).

RESULTS

The analysis of observer diagnostic confidence revealed higher intragroup (kappa = 0.63-0.83) than intergroup (kappa = 0.47-0.63) observer agreement. The experienced observers showed higher diagnostic performance in malignancy diagnosis than did inexperienced observers (overall accuracy: group 1, 63.3%-72.8%; group 2, 75.9%-93.1%; P < .05, chi(2) test).

CONCLUSIONS

The diagnostic performance of CEUS in liver tumor characterization was dependant on the observer's level of experience.

Usefulness of Sonazoid contrast-enhanced ultrasonography for hepatocellular carcinoma: comparison with pathological diagnosis and superparamagnetic iron oxide magnetic resonance images

OBJECTIVE

We investigated the usefulness of Sonazoid contrast-enhanced ultrasonography (Sonazoid-CEUS) in the diagnosis of hepatocellular carcinoma (HCC). The examination was performed by comparing the images during the Kupffer phase of Sonazoid-CEUS with superparamagnetic iron oxide magnetic resonance (SPIO-MRI).

METHODS

The subjects were 48 HCC nodules which were histologically diagnosed (well-differentiated HCC, n=13; moderately differentiated HCC, n=30; poorly differentiated HCC, n=5). We performed Sonazoid-CEUS and SPIO-MRI on all subjects. In the Kupffer phase of Sonazoid-CEUS, the differences in the contrast agent uptake between the tumorous and non-tumorous areas were quantified as the Kupffer phase ratio and compared. In the SPIO-MRI, it was quantified as the SPIO-intensity index. We then compared these results with the histological differentiation of HCCs.

RESULTS

The Kupffer phase ratio decreased as the HCCs became less differentiated (P<0.0001; Kruskal-Wallis test). The SPIO-intensity index also decreased as HCCs became less differentiated (P<0.0001). A positive correlation was found between the Kupffer phase ratio and the SPIO-MRI index (r=0.839). In the Kupffer phase of Sonazoid-CEUS, all of the moderately and poorly differentiated HCCs appeared hypoechoic and were detected as a perfusion defect, whereas the majority (9 of 13 cases, 69.2%) of the well-differentiated HCCs had an isoechoic pattern. The Kupffer phase images of Sonazoid-CEUS and SPIO-MRI matched perfectly (100%) in all of the moderately and poorly differentiated HCCs.

CONCLUSION

Sonazoid-CEUS is useful for estimating histological grading of HCCs. It is a modality that could potentially replace SPIO-MRI.

[Contrast-enhanced ultrasound and liver imaging: review of the literature]

The advent of second-generation microbubble ultrasound contrast agents and the development of contrast specific ultrasound techniques improved the ability of contrast enhanced ultrasound (CEUS) in detecting and characterizing focal liver lesions, opening new prospects in liver imaging. A Medline search in June 2008 identified 72 published studies that used CEUS in focal liver lesion detection, characterization, and follow-up to monitor tumor ablation procedures and antiangiogenic treatment. The purpose of this paper, based on literature review, is to describe the technical recommendations when using CEUS for liver imaging and to define the different vascular patterns of the most relevant benign and malignant lesions. Diagnostic performance of CEUS and the important clinical indications are also presented and discussed. CEUS is increasingly accepted in clinical use for diagnostic imaging and post-interventional workup liver imaging. It may replace many computed tomography and magnetic resonance imaging examinations in the near future, according to the European Federation of Societies for Ultrasound in Medicine and Biology guidelines.

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.

Value of liver parenchymal phase contrast-enhanced sonography to diagnose premalignant and borderline lesions and overt hepatocellular carcinoma

OBJECTIVE

The objective of our study was to investigate whether liver parenchymal phase contrast-enhanced sonography can provide additional information for assessing histologic grades of hepatocellular carcinoma (HCC).

SUBJECTS AND METHODS

Contrast-enhanced sonography using Levovist of 50 hepatic nodules was performed. The vascular and liver parenchymal perfusion patterns were evaluated. The sensitivity, specificity, and accuracy of the histologic diagnosis of the tumors using vascular phase imaging only and systematically combined vascular phase imaging with liver parenchymal phase imaging were calculated. We also performed histologic examination and immunostaining for the detection of Kupffer cells and calculated the Kupffer cell count in the tumorous tissue relative to that in the nontumorous tissue (Kupffer cell ratio) and quantitatively evaluated the relationship between the Kupffer cell ratio and the perfusion patterns seen on liver parenchymal phase imaging.

RESULTS

The specificity and accuracy of contrast-enhanced sonography in the diagnosis of dysplastic nodules and of moderately and poorly differentiated HCCs were improved by adding liver parenchymal phase imaging (dysplastic nodules, 74% and 78% vs 83% and 86%, respectively; moderately and poorly differentiated HCCs, 74% and 86% vs 85% and 92%). The diagnostic accuracy of contrast-enhanced sonography for dysplastic nodules showed a trend of improvement with the addition of liver parenchymal phase imaging (p = 0.07). Kupffer cell ratios for tumors that showed hypoperfusion during the liver parenchymal phase were significantly lower than those for tumors showing isoperfusion (p < 0.05).

CONCLUSION

Adding liver parenchymal phase imaging to contrast-enhanced sonography protocols may yield additional information that can be used to assess histologic grades of tumor and that leads to an improvement in the differential diagnosis of nodular lesions associated with the cirrhotic liver. Further case studies are required in larger numbers of patients for a longer follow-up period.

Multistep human hepatocarcinogenesis: correlation of imaging with pathology

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. The majority of HCCs develop in cirrhotic livers, and the early detection and characterization of this entity is very important. Pathologically, human HCC develops in a multistep fashion in the following sequence: from low-grade dysplastic nodule (LGDN), to high-grade dysplastic nodule (HGDN), early HCC, well-differentiated HCC, nodule-in-nodule HCC, and, finally, to moderately differentiated HCC. Differentiation between early HCC and DN is the most important issue in the clinical setting. CT during hepatic angiography (CTHA) and CT during arterial portography (CTAP) are the most sensitive tools in the differentiation of premalignant/borderline lesions (LGDN and HGDN) and early HCC. Recent progress in imaging modality, especially Sonazoidenhanced US and Gd-EOB-DTPA MRI, is starting to play a very important role in the imaging of multistep hepatocarcinogenesis, resulting in changing the therapeutic strategy of these nodular lesions associated with liver cirrhosis.

Contrast-enhanced ultrasound assessment of arterial vascularization of small nodules arising in the cirrhotic liver

BACKGROUND AND AIM

Aim of this study was to compare contrast-enhanced ultrasound and multi-detector row computed tomography in detecting arterial hypervascularity in small cirrhotic nodules.

PATIENTS AND METHODS

Sixty-two nodules (41 measuring 1.0-2.0 cm, 21 measuring 2.1-3.0 cm) found in 55 cirrhotic patients were examined with both methods. Lesions displaying arterial hypervascularity with washout in the portal/venous phase on both studies were considered hepatocellular carcinomas and treated; all other nodules were subjected to ultrasound-guided fine-needle biopsy.

RESULTS

The larger nodules (2.1-3.0 cm) included 19 hepatocellular carcinomas (90%), 1 macroregenerative nodule type I and 1 macroregenerative nodule type II; 35 (87%) of the smaller nodules were hepatocellular carcinomas, 2 were macroregenerative nodules type I, 2 macroregenerative nodules type II and 2 hemangiomas. The two studies yielded concordant findings for 54 nodules (87%), including 46 hypervascular on both examinations and 8 that were consistently hypovascular. Two of the latter nodules were hepatocellular carcinomas. The other eight nodules displayed arterial hypervascularity on only one of the studies. Six of these (75%) were hepatocellular carcinomas, including five that were negative in the contrast-enhanced ultrasound study.

CONCLUSION

Computed tomography and contrast-enhanced ultrasound show high agreement in the vascular classification of small nodules detected by ultrasound in cirrhotic livers, although the former technique was slightly more sensitive in the detection of arterial hypervascularization.

A novel perfusion imaging technique of the pancreas: contrast-enhanced harmonic EUS (with video)

BACKGROUND

Contrast-enhanced harmonic-imaging techniques have been unavailable for EUS because of the limited frequency bandwidth and acoustic power output of current echoendoscopes.

OBJECTIVE

To investigate the contrast harmonic imaging technique by using a prototype echoendoscope equipped with an adequate broad-band transducer that can detect harmonic signals from the US contrast agents.

DESIGN

Identification of optimal settings (study I) and preliminary clinical investigations (study II).

SETTING

Bethesda General Hospital Bergedorf.

PATIENTS

A total of 104 patients undergoing standard EUS examinations.

INTERVENTIONS

Contrast-enhanced harmonic EUS (CEH-EUS) was performed by using a prototype echoendoscope and extended pure harmonic detection mode, a specific mode for contrast harmonic imaging.

MAIN OUTCOME MEASUREMENTS

In study I, time-intensity curves for peak signal intensity were calculated after infusion of a contrast agent, SonoVue, and the changes in echo intensity were compared for different mechanical indices and interval times. In study II, intermittent and real-time continuous images of pancreatobiliary and gastroduodenal diseases obtained by CEH-EUS were evaluated in comparison with contrast-enhanced power-Doppler EUS (CED-EUS).

RESULTS

In study I, with the optimal mechanical index (0.4), homogeneous parenchymal perfusion images of the pancreas were obtained by intermittent imaging, and finely branching vessels of the pancreas were obtained with real-time continuous imaging. In study II, apparent perfusion and vessel images were observed in pancreatobiliary carcinomas, GI stromal tumors, and lymph-node metastases. CED-EUS failed to depict images of the fine vessels and parenchymal perfusion.

LIMITATIONS

The subjective nature of the findings, with a limited number of patients.

CONCLUSIONS

CEH-EUS successfully visualized parenchymal perfusion and microvasculature in the pancreas and may play an important role in the differential diagnosis of digestive diseases.

Management of hepatocellular carcinoma in Japan: consensus-based clinical practice manual proposed by the Japan Society of Hepatology

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer death not only in Japan but worldwide. Clinical Practice Guidelines for HCC were published in 2001 by the European Society of Study of the Liver (EASL) and in 2005 by the American Association for the Study of Liver Disease (AASLD). However, these guidelines have proven to be somewhat unsuitable for Japanese patients. In 2005, supported by the Japanese Ministry of Health, Labor and Welfare, Evidence-Based Clinical Practice Guidelines for HCC were compiled. Based on 'evidence-based' guidelines and the consensus of an expert panel on HCC, the Japan Society of Hepatology (JSH) published the Consensus-Based Clinical Practice Manual in 2007. In this article, the content of this manual, especially issues on surveillance, diagnosis, staging, and treatment, is summarized.

Can contrast-enhanced ultrasonography characterize focal liver lesions and differentiate between benign and malignant, thus providing a one-stop imaging service for patients?()

PURPOSE

Contrast-enhanced ultrasonography (CEUS) displays high sensitivity and specificity in characterizing focal liver lesions (FLLs). We attempted to determine how often CEUS provides an unequivocal diagnosis of FLLs that does not require additional imaging studies.

MATERIALS AND METHODS

Seventy-three patients with 146 FLLs were scanned with B-mode, Doppler, and contrast-enhanced US (2 × 2.4 ml SonoVue, low MI, 4-6 MHz curved array transducer, Toshiba Aplio/Siemens-Acuson Sequoia). Data were digitally stored and transferred to a work station with the GE PACS system. Images were reviewed by a consultant radiologist experienced in CEUS and interpreted in accordance with the criteria for characterizing FLLs published by the European Federation of Societies for Ultrasound in Medicine and Biology. Diagnoses were compared with those based on computed tomography (CT) and/or magnetic resonance (MR) findings if these were available. However, our aim was to assess the frequency with which CEUS provided diagnoses that were considered reliable enough to exclude the need for other imaging studies. Therefore, the CEUS diagnoses were not necessarily confirmed by other methods.

RESULTS

Based on CEUS findings alone, 130/146 (89.0%) FLLs could be classified as benign or malignant, and in 118/146 (80.8%) cases, the lesion could be specifically identified. The other 28/146 (19.2%) FLLs could not be characterized based on CEUS data alone. In 58 (80.8%) of the 73 patients with multiple FLLs, CEUS findings were sufficient to establish the benign vs. malignant nature of all the patient's lesions; in 51/73 (69.9%) patients, all the lesions could also be characterized with CEUS. In the remaining cases, at least one lesion required additional imaging to determine whether it was malignant (14/73, 19.2%) or to establish its identity (22/73, 30.1%). In 4/73 (5.5%) patients, CEUS revealed additional lesions not detected on B-mode US.

CONCLUSIONS

CEUS alone was sufficient to classify 89.0% of the FLLs as benign or malignant, and in 80.8% it was also regarded as sufficient to identify the lesion. It served as a one-stop diagnostic test for 80.8% of the patients, reducing the need for CT-MR scans and providing savings in terms of radiation exposure, time, and money.

Enhancement patterns of hepatocellular carcinoma at contrast-enhanced US: comparison with histologic differentiation

PURPOSE

To retrospectively compare the arterial and portal venous phase enhancement patterns of hepatocellular carcinoma (HCC) at contrast material-enhanced ultrasonography (US) with the degree of HCC histologic differentiation.

MATERIALS AND METHODS

This study was approved by the research ethics board, and informed consent was obtained. The study population included 112 consecutive patients (91 men, 21 women; aged 25-86 years) with 112 histologically proved HCCs: 23 well differentiated, 77 moderately differentiated, and 12 poorly differentiated. All underwent continuous real-time low-mechanical-index contrast-enhanced US from wash-in of contrast material to 300 seconds by using a blood-pool microbubble agent. Initial image interpretation included arterial enhancement, dysmorphic intratumor arteries, and presence and time of negative enhancement (washout). Enhancement patterns were compared with histologic differentiation by using the Fisher exact test.

RESULTS

In the arterial phase, 97 of 112 (87%) HCCs showed hypervascularity, with a significantly higher proportion in moderately differentiated HCCs (74 of 77, 96%) when compared with well- (14 of 23, 61%; P<.001) and poorly differentiated HCC (nine of 12, 75%; P<.004). Eight of 112 (7%) were isovascular and seven (6%) were hypovascular. Dysmorphic arteries were seen in 81 (72%) HCCs. Of 97 hypervascular tumors, only 42 (43%) showed typical washout by 90 seconds. Late washout appeared in 25 (26%) HCCs in the 91-180 seconds phase and in 21 (22%) in the 181-300 seconds phase. The remaining nine showed no washout up to 300 seconds and seven (78%) were well-differentiated HCCs.

CONCLUSION

Moderately differentiated HCC generally shows classic enhancement features, while well- and poorly differentiated tumors account for most atypical variations. Extended observation in the portal phase is important as late washout occurs with slightly more frequency than washout in the conventionally defined portal venous phase.

The use of imaging in the diagnosis and staging of hepatobiliary malignancies

This review addresses the optimal use of imaging in the diagnosis, staging, and treatment planning of patients with hepatobiliary neoplasms. We focus on primary liver cancers, including hepatocellular carcinoma and intrahepatic cholangiocarcinoma as well as extrahepatic biliary tract malignancies, including hilar cholangiocarcinoma and gallbladder cancer. In each section, we provide an overview of the staging requirements for each disease followed by a discussion of various imaging modalities that can be used to optimally stage the disease and plan therapy.

New sonographic techniques for the diagnosis and treatment of hepatocellular carcinoma

Ultrasound (US) contrast agents such as Levovist and Sonazoid are now commercially available in Japan. Innovative contrast agents and ultrasound technologies have dramatically changed both diagnostic and treatment strategies for hepatocellular carcinoma (HCC). Contrast-enhanced US is extremely useful in the differential diagnosis of hepatic tumors as well as in evaluation of post-treatment response of HCC after lipiodol transarterial chemoembolization and radio frequency ablation. Harmonic US sensitively detects residual cancer cells in HCC patients after treatment, to facilitate accurate guidance for needle insertion for US monitoring; no other imaging modalities, including computed tomography (CT) or magnetic resonance imaging (MRI), have such capability. In 2005, the breakthrough technology of pure arterial phase imaging, which depicts only intranodular arterial accumulated maximum intensity projection images, was developed from advanced raw data storing and accumulation technologies. This technique can clearly identify whether blood supplyin the tumor is of arterial or portal origin, to facilitate the non-invasive characterization of nodular lesions associated with liver cirrhosis. Again, CT or MRI do not have such capabilities. This innovative technique can help differentiate premalignant lesions from overt HCC. Concurrent real-time imaging of multi-detector CT and US, known as real-time virtual sonography, has recently become available. This technique greatly facilitates the treatment guidance for HCC. These newly introduced sonographic techniques are dramatically changing the diagnostic and therapeutic strategies for HCC, which are expected to improve the prognosis of HCC patients.

Recent advances in the diagnosis of hepatocellular carcinoma

In the last decade, new imaging techniques have become available, offering the possibility of investigating contrast perfusion of liver nodules in cirrhosis. It is now accepted that a non-invasive diagnosis of hepatocellular carcinoma (HCC) can be established based on the vascular pattern, obtained with pure blood pool contrast agents. The diagnostic pattern includes: hypervascularity in the arterial phase (15-35 s after contrast injection), consisting in a contrast signal in the nodule greater than in the surrounding parenchyma, followed by contrast wash out, which leads the nodule to show the same, or, more specifically, a lower contrast signal, than the surrounding parenchyma in the portal and late phases (>40 s after injection). Such a pattern can be obtained not only by computed tomography or magnetic resonance imaging, but also by contrast-enhanced ultrasonography, most simply with real-time low mechanical index harmonic imaging ultrasound equipment with second-generation ultrasound contrast agents. The risk of false-positive diagnosis of malignancy isnearly abolished when the functional vascular pattern is not the only feature, but is superimposed on a nodule visible also without contrast. One single contrast imaging technique may suffice to make a diagnosis of HCC if the nodule is >1 cm in diameter and has developed during a surveillance program. Other types of contrast agents, such as those taken up by the reticular-endothelial system cells, may offer additional diagnostic clues, but definitive evidence of their efficacy is still to be produced. In conclusion, contrast-enhanced imaging techniques now offer the possibility of a non-invasive diagnosis of HCC in a large number of cases, reducing the need of invasive investigations, such as ultrasound-guided biopsy or angiography.

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.

Diagnosis of gallbladder diseases by contrast-enhanced phase-inversion harmonic ultrasonography

We evaluated the usefulness of contrast-enhanced ultrasonography(US) for detecting and differentiating gallbladder lesions. Contrast-enhanced coded phase-inversion harmonic US was performed on 90 patients with gallbladder abnormalities. After administering Levovist, we observed the gallbladders in real time. Contrast-enhanced coded phase-inversion harmonic ultrasonography was compared with B-mode US and contrast-enhanced computer tomography (CT) with regard to the sensitivity and specificity in depicting the elevated gallbladder lesions. Furthermore, we assessed how the vascular patterns of the elevated gallbladder lesions depicted by contrast-enhanced US correlated with the diagnosis. Contrast-enhanced US efficiently discriminated true lesions from biliary sludge, unlike B-mode US. Consequently, contrast-enhanced US was more specific (100%) than B-mode US (81%), although their sensitivities were similar (98% and 96%, respectively). Contrast-enhanced US was also more sensitive that contrast-enhanced CT (98% versus 79%), although the two methods were equally sensitive (100% versus 95%). We classified the vascular patterns of the abnormalities depicted by contrast-enhanced US in the 90 cases into types 1 to 4, which represent branch-like, heterogeneous, homogeneous, and avascular patterns, respectively. All type 1 and 2 lesions were over 10 mm in size while most (88%) type 3 lesions were 10 mm or less in size. While the majority of carcinomas (86%) were type 1 or 2, three benign lesions also showed these patterns. Thus, the vascular pattern may simply reflect the size of the lesion and therefore its usefulness in diagnosing gallbladder lesions may be limited. Nevertheless, contrast-enhanced US is clearly superior to the other techniques in discriminating biliary sludge from other lesions.

Contrast harmonic sonography-guided radiofrequency ablation therapy versus B-mode sonography in hepatocellular carcinoma: prospective randomized controlled trial

OBJECTIVE

The purpose of this study was to evaluate the effectiveness of contrast harmonic sonographic guidance in radiofrequency ablation of locally progressive hepatocellular carcinoma poorly depicted with B-mode sonography.

SUBJECTS AND METHODS

A series of 40 patients with hepatocellular carcinoma with local tumor progression poorly depicted with B-mode sonography were randomly treated with radiofrequency ablation guided by either contrast harmonic sonography (n = 20) or conventional B-mode sonography (n = 20). Unpaired Student's t tests were performed to compare numbers of treatment sessions.

RESULTS

Treatment analysis showed that the complete ablation rate after a single treatment session was significantly higher in the contrast harmonic sonography group than in the B-mode sonography group (94.7% vs 65.0%; p = 0.043) and that the number of treatment sessions was significantly lower in the contrast harmonic sonography group (mean, 1.1 +/- 0.2 vs 1.4 +/- 0.6; p =0.037).

CONCLUSION

Contrast harmonic sonography-guided radiofrequency ablation is an efficient technique for guiding further ablation of local tumor progression not clearly demarcated with B-mode sonography.