Characterization of liver lesions by real-time contrast-enhanced ultrasonography

Benign liver lesions 2022: Guideline for clinical practice of Associazione Italiana Studio del Fegato (AISF), Società Italiana di Radiologia Medica e Interventistica (SIRM), Società Italiana di Chirurgia (SIC), Società Italiana di Ultrasonologia in Medicina e Biologia (SIUMB), Associazione Italiana di Chirurgia Epatobilio-Pancreatica (AICEP), Società Italiana Trapianti d'Organo (SITO), Società Italiana di Anatomia Patologica e Citologia Diagnostica (SIAPEC-IAP) - Part I - Cystic lesions

Benign liver lesions are increasingly diagnosed in daily clinical practice due to the growing use of imaging techniques for the study of the abdomen in patients who have non-specific symptoms and do not have an increased risk of hepatic malignancy. They include simple or parasitic cysts and solid benign tumors which differ widely in terms of prevalence, clinical relevance, symptoms and natural history and often lead to significant clinical problems relating to diagnosis and clinical management. Following the need to have updated guidelines on the management of benign focal liver lesions, the Scientific Societies mainly involved in their management have promoted the drafting of a new dedicated document. This document was drawn up according to the present Italian rules and methodologies necessary to produce clinical, diagnostic, and therapeutic guidelines based on evidence. Here we present the first part of the guideline, concerning the characterization of focal hepatic lesions detected by ultrasound, and the diagnosis and clinical management of simple and parasitic hepatic cysts, and of polycystic liver disease.

Quantitative Ultrasound Elastography Methods in Focal Liver Lesions Including Hepatocellular Carcinoma: From Diagnosis to Prognosis

ABSTRACT

The ability of ultrasound elastography to diagnose focal liver lesions and determine their prognoses including hepatocellular carcinoma (HCC) is unclear. At present, radiofrequency ablation and liver resection are the most common treatments for HCC. However, the survival rate remains disappointing because of recurrences and postoperative liver failure, necessitating the development of noninvasive approaches. There is currently no systematic definition of an elastic technique for measuring liver stiffness to predict the recurrence of HCC after radiofrequency ablation and postoperative liver failure. In this review, recent advances in ultrasound elastography for the diagnosis and prognosis of focal liver lesions are discussed including HCC.

ACR Appropriateness Criteria® Liver Lesion-Initial Characterization

Incidental liver masses are commonly identified on imaging performed for other indications. Since the prevalence of benign focal liver lesions in adults is high, even in patients with primary malignancy, accurate characterization of incidentally detected lesions is of paramount clinical importance. This document reviews utilization of various imaging modalities for characterization of incidentally detected liver lesions, discussed in the context of several clinical scenarios. For each clinical scenario, a summary of current evidence supporting the use of a given diagnostic modality is reported. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Multimodality Approach in Detection and Characterization of Hepatic Metastases

Early detection of liver metastases is important in patients with known primary malignancies. This plays an important role in treatment planning and impacts on further management of certain primary malignancies.

Magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography-computed tomography scans are reported to have high accuracy in the diagnosis of intrahepatic lesions. MRI in particular has the advantages of its high tissue sensitivity and its multiparametric approach.

Hepatic metastatic lesions have considerable overlap in their radiological appearance, and in this article the imaging appearance of various hepatic metastasis and approach is described.

Safety Profile of Musculoskeletal Contrast-Enhanced Ultrasound with Sulfur Hexafluoride Contrast Agent

PURPOSE

Muscle, bone and tendon regeneration depend on the microperfusion of the corresponding tissue which can be quantified with contrast-enhanced ultrasound (CEUS) using sulfur hexafluoride contrast agent (SonoVue®). This study investigated the incidence of adverse events (AEs) in musculoskeletal patients and gives an overview of musculoskeletal CEUS applications.

PATIENTS AND METHODS

Based on 13 studies in a standardized monocentric setting, a total of 2268 CEUS examinations in 764 patients were performed and AEs due to the administration of sulfur hexafluoride contrast agent were classified as either mild, moderate or severe.

RESULTS

No fatal events occurred. AEs were reported in three cases, of which only one was classified as severe and two as mild. The total rate of all AEs was 0.13% and 0.04% for severe AEs.

CONCLUSION

The present analysis confirms the safety of musculoskeletal CEUS using sulfur hexafluoride contrast agent with a lower rate of AEs than that reported for other contrast agents even in elderly patients with concomitant diseases.

Nodular focal fat sparing of liver mimicking hepatocellular carcinoma in contrast-enhanced ultrasound: A case report

INTRODUCTION

Focal fatty sparing is a manifestation of fatty liver. Nodular focal fatty sparing of liver sometimes is a mimicker of malignant lesion, especially metastatic tumor. There are some case reports about this kind of tricks revealed by computed tomography (CT) and magnetic resonance imaging. However, few reports described nodular focal sparing of liver presenting an enhancement mode of hepatocellular carcinoma (HCC) in contrast-enhanced ultrasound (CEUS).

PATIENT CONCERNS

A 37-year-old male had a long history of alcohol abuse and hepatitis B virus infection. Routine blood examination showed an elevation of triglyceride, and tumor markers were unremarkable. Conventional ultrasound indicated a diffuse fatty liver with a hypoechoic nodular lesion. CEUS revealed hyperenhancement in arterial phase and washout in late phase of this hypoechoic lesion. Contrast-enhanced CT showed a similar enhancement mode of the mass with CEUS.

DIAGNOSIS

A clinical diagnosis of HCC was made. Then, liver resection was conducted. Postoperative histopathologic and immunohistochemical results of the lesion revealed no presence of tumor cells except for heterogeneous hepatic steatosis. So a final diagnosis of hepatic focal fatty sparing was determined.

INTERVENTIONS

Liver resection was conducted according to the clinical diagnosis of HCC.

OUTCOMES

After general postoperative administration, the patient was told to discharge. Then, he had been undergoing regular serological tests and imaging examinations in our hospital for 39 months and found no manifestation of liver tumor.

CONCLUSION

According to guidelines, it is typical that hepatic focal fatty change (FFC) presents a mode of persistent iso-enhancement in CEUS. However, atypical enhancement presence of FFC in imaging examinations may occur and lead to misdiagnosis, which calls for more attention.

ACR Appropriateness Criteria® Suspected Liver Metastases

Liver metastases are the most common malignant liver tumors. The accurate and early detection and characterization of liver lesions is the key to successful treatment strategies. Increasingly, surgical resection in combination with chemotherapy is effective in significantly improving survival if all metastases are successfully resected. MRI and multiphase CT are the primary imaging modalities in the assessment of liver metastasis, with the relative preference toward multiphase CT or MRI depending upon the clinical setting (ie, surveillance or presurgical planning). The optimization of imaging parameters is a vital factor in the success of either modality. PET/CT, intraoperative ultrasound are used to supplement CT and MRI. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Contrast enhanced ultrasound guided biopsies of liver lesions not visualized on standard B-mode ultrasound-preliminary experience

Background

To assess the technical success of contrast enhanced ultrasound (CEUS) guided biopsies of liver lesions poorly visualized on B-mode ultrasound.

Methods

Patients were selected during the procedure based on the real-time clinical scenario of unsatisfactory B-mode ultrasound lesion visualization and all patients would have otherwise undergone CT guided liver lesion biopsy. A total of 26 patients underwent CEUS guided biopsy and were included in this retrospective analysis. The review of the patients' files included demographic information, lesion characteristics on imaging, procedural details and pathology outcome. Technical success was defined as concordance between the radiological findings, pathology report and clinical follow-up-demonstrating lack of need for re-biopsy or re-biopsy with identical pathological results. Patients with less than 2 months follow-up were excluded from the study.

Results

CEUS guided liver biopsy was successful in 23 out of 26 patients (88.5%). The average procedure time was 30.7±12.3 minutes and the average lesion size was 2.2±1.7 cm. The majority of lesions (80.8%) were hypoenhancing on the delayed phase of CEUS. The mean number of samples taken from each lesion per procedure was 3.2 (±1.7).

Conclusions

CEUS guidance biopsies of focal liver lesions (FLL) that were difficult to visualize on B-mode ultrasound demonstrated high success rate and may be an evolving image guidance modality in selected patients to avoid CT guided procedures.

Clinical Application of Contrast-Enhanced Ultrasound Using High-Frequency Linear Probe in the Detection of Small Colorectal Liver Metastases

To compare the performance of contrast-enhanced ultrasound (CEUS) using high-frequency linear and convex probes in the detection of small colorectal liver metastases (CRLMs). A total of 85 patients with 143 small CRLMs were evaluated. High-frequency ultrasound (US) and CEUS detected significantly more superficial lesions within 60 mm below the skin than a convex probe (p <0.05). The detection rate decreased in the chemotherapy group, especially when using a convex probe for US (p <0.05). By combining convex and linear probes, detection rates of US and CEUS were significantly higher than that of a convex or a linear probe alone (p <0.05). High-frequency US and CEUS helped to improve detection of small CRLMs and reduce the influence of chemotherapy. For patients with a high risk of CRLMs and those after chemotherapy, we recommend first scanning the liver by using a convex probe and subsequently screening the surface area of the liver and suspicious small lesions by using a linear probe.

Contrast-enhanced US for characterization of focal liver lesions: a comprehensive meta-analysis

OBJECTIVES

This meta-analysis was performed to evaluate the accuracy of contrast-enhanced ultrasound (CEUS) in differentiating malignant from benign focal liver lesions (FLLs).

METHODS

Cochrane Library, PubMed and Web of Science databases were systematically searched and checked for studies using CEUS in characterization of FLLs. Data necessary to construct 2×2 contingency tables were extracted from included studies. The QUADAS tool was utilized to assess the methodologic quality of the studies. Meta-analysis included data pooling, subgroup analyses, meta-regression and investigation of publication bias was comprehensively performed.

RESULTS

Fifty-seven studies were included in this meta-analysis and the overall diagnostic accuracy in characterization of FLLs was as follows: pooled sensitivity, 0.92 (95%CI: 0.91-0.93); pooled specificity, 0.87 (95%CI: 0.86-0.88); diagnostic odds ratio, 104.20 (95%CI: 70.42-154.16). Subgroup analysis indicated higher diagnostic accuracy of the second-generation contrast agents (CAs) than the first-generation CA (Levovist; DOR: 118.27 vs. 62.78). Furthermore, Sonazoid demonstrated the highest diagnostic accuracy among three major CAs (SonoVue, Levovist and Sonazoid; DOR: 118.82 vs. 62.78 vs. 227.39). No potential publication bias was observed of the included studies.

CONCLUSION

CEUS is an accurate tool to stratify the risk of malignancy in FLLs. The second-generation CAs, especially Sonazoid may greatly improve diagnostic performance.

KEY POINTS

• CEUS shows excellent diagnostic accuracy in differentiating malignant from benign FLLs. • The second-generation CAs have higher diagnostic accuracy than first-generation CAs. • Sonazoid demonstrates the highest diagnostic accuracy among three major CAs.

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.

Contrast-enhanced ultrasound features of histologically proven small (≤20 mm) liver metastases

OBJECTIVE

We analyzed contrast-enhanced ultrasound (CEUS) features of histologically proved small (≤20 mm) liver metastases, in comparison to small (≤20 mm) hepatocellular carcinomas (HCC), to define the differentiate diagnoses value of CEUS in clinical practice.

MATERIAL AND METHODS

Eighty-two cases of small (≤20 mm) liver metastases and 84 cases of small (≤20 mm) HCC were retrospectively reviewed. All patients had CEUS images. Two radiologists assessed CEUS enhancement pattern and time of enhancement in consensus. Statistical analyses were performed using SPSS v.19.0 (SPSS Inc., Chicago, IL). The χ² test and the independent sample t-test were used to compare the differences.

RESULTS

Comparing to small HCCs, rapid rim-like hyper-enhancement in arterial phase (56.1% in liver metastases vs. 2.3% in HCCs, p < .01), rapid wash-out and become hypo-enhancement in late arterial phase or early portal venous phase (96.4% in liver metastases vs. 22.6% in HCCs, p < .01) with central non-enhanced area in late phase were characteristic CEUS features of small metastases.

CONCLUSIONS

CEUS imaging enhancement findings reliably offer typical signs of small liver metastases, differentiate effectively with small HCCs. CEUS can help to improve the diagnostic confidence of small liver metastases.

Contrast-enhanced ultrasonography in the evaluation of incidental focal liver lesions: A cost-effectiveness analysis

AIM

To determine whether contrast-enhanced ultrasonography (CEUS) as the first-line method is more cost-effective in evaluating incidentally discovered focal liver lesions (FLLs) than is computed tomography (CT) and magnetic resonance imaging (MRI).

METHODS

Between 2010 and 2015, our prospective study enrolled 459 patients with incidentally found FLLs. The biological nature of FLLs was assessed by CEUS in all patients. CT or MRI examinations were added in unclear cases. The sensitivity and specificity of CEUS were calculated. The total costs of CEUS examinations and of the added examinations performed in inconclusive cases were calculated. Afterwards, the theoretical expenses for evaluating incidentally discovered FLLs using CT or MRI as the first-line method were calculated. The results were compared.

RESULTS

The total cost of the diagnostic process using CEUS for all enrolled patients with FLLs was 75884 USD. When the expenses for additional CT and MRI examinations performed in inconclusive cases were added, the total cost was 90540 US dollar (USD). If all patients had been examined by CT or MR as the first-line method, the costs would have been 78897 USD or 384235 USD, respectively. The difference between the cost of CT and CEUS was 3013 USD (4%) and that between MRI and CEUS was 308352 USD (406.3%). We correctly described 97.06% of benign or malignant lesions, with 96.99% sensitivity and 97.09% specificity. Positive predictive value was 94.16% and negative predictive value was 98.52%. In cases with 4 and more lesions, malignancy is significantly more frequent and inconclusive findings significantly less frequent (P < 0.001).

CONCLUSION

While the costs of CEUS and CT in evaluating FLLs are comparable, CEUS examination is far more cost-effective in comparison to MRI.

Dynamic enhancement pattern of intrahepatic cholangiocarcinoma on contrast-enhanced ultrasound: the correlation with cirrhosis and tumor size

PURPOSE

To retrospectively evaluate the dynamic enhancement pattern of contrast-enhanced ultrasound (CEUS) in intrahepatic cholangiocarcinoma (ICC) of varying sizes and hepatic backgrounds.

MATERIALS AND METHODS

CEUS was performed in 98 pathologically confirmed ICCs (n = 39 < 30 mm, n = 59 > 30 mm; n = 45 with cirrhosis and n = 53 with normal liver). The dynamic enhancement pattern of CEUS was retrospectively analyzed.

RESULTS

In the arterial phase, heterogeneous hyper-enhancement was more frequent in ICCs with cirrhosis (21/45, 46.7% vs. 11/53, 20.8% in ICCs with normal liver, p = 0.009), while peripheral hyper-enhancement and hypo-enhancement were more common in ICCs with normal liver (14/53, 26.4%; 11/53, 20.8% vs. 2/45, 4.4%; 2/45, 4.4% in ICCs with cirrhosis, p = 0.005 and 0.033, respectively). There were no significant differences between portal and delayed phases. In ICCs < 30 mm, homogeneous hyper-enhancement was more frequently identified (27/39, 69.2% vs. 10/59, 16.9% in ICCs > 30 mm, p < 0.001), whereas in ICCs > 30 mm, heterogeneous, and peripheral hyper-enhancement were more commonly observed (26/59, 44.1% vs. 6/39, 15.4% in ICCs < 30 mm, p = 0.004, and 14/59, 23.7% vs. 2/39, 5.1% in ICCs < 30 mm, p = 0.023, respectively). The washout pattern in portal and delayed phases were not significantly different in ICCs with different sizes. 60.7% (17/28) ICCs < 30 mm and 85.2% (23/27) ICCs > 30 mm with cirrhosis, together with 66.7% (14/21) ICCs < 30 mm with normal liver displayed intense contrast agent uptake (homogeneous or heterogeneous hyper-enhancement) in arterial phase followed by washout in portal and delayed phase, which was much higher than that in ICCs > 30 mm with normal liver (34.4%, 11/32, p < 0.001, <0.001 and =0.027, respectively).

CONCLUSION

The CEUS dynamic enhancement pattern of ICC varies with size and hepatic background. The enhancement pattern is indistinguishable from hepatocellular carcinoma on CEUS in most ICCs with cirrhosis and in most ICCs < 30 mm with normal liver.

Non-invasive diagnostic imaging of colorectal liver metastases

Colorectal cancer is one of the few malignant tumors in which synchronous or metachronous liver metastases [colorectal liver metastases (CRLMs)] may be treated with surgery. It has been demonstrated that resection of CRLMs improves the long-term prognosis. On the other hand, patients with un-resectable CRLMs may benefit from chemotherapy alone or in addition to liver-directed therapies. The choice of the most appropriate therapeutic management of CRLMs depends mostly on the diagnostic imaging. Nowadays, multiple non-invasive imaging modalities are available and those have a pivotal role in the workup of patients with CRLMs. Although extensive research has been performed with regards to the diagnostic performance of ultrasonography, computed tomography, positron emission tomography and magnetic resonance for the detection of CRLMs, the optimal imaging strategies for staging and follow up are still to be established. This largely due to the progressive technological and pharmacological advances which are constantly improving the accuracy of each imaging modality. This review describes the non-invasive imaging approaches of CRLMs reporting the technical features, the clinical indications, the advantages and the potential limitations of each modality, as well as including some information on the development of new imaging modalities, the role of new contrast media and the feasibility of using parametric image analysis as diagnostic marker of presence of CRLMs.

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.

Contrast-enhanced ultrasound in liver cancer

Contrast-enhanced ultrasound (CEUS) is a sure, noninvasive, repeatable imaging technique widely used in the characterization of benign and malignant liver lesions. The European Federation of Societies for Ultrasound in Medicine and Biology guidelines suggest the typical CEUS features of liver lesions as criteria for the noninvasive diagnosis in cirrhotic and not-cirrhotic patients. The clinical application of CEUS in the liver study is summarized in this review; the contrast-enhanced patterns of the most frequent liver lesions are described (hepatocellular and cholangiocellular carcinoma, liver metastases, hemangioma, focal nodular hyperplasia, adenoma). The role of this imaging technique in the diagnostic algorithm of liver malignancy is illustrated and the CEUS application in hepatologic and oncological settings is depicted.

High correlation between microbubble contrast-enhanced ultrasound, magnetic resonance and histopathology in the evaluation of hepatocellular carcinoma

OBJECTIVES

To evaluate the efficacy of microbubble contrast ultrasound in diagnosis of hepatocellular carcinoma and to compare its results with those of magnetic resonance and histopathology.

METHODS

A total of 29 patients suffering from chronic liver diseases and awaiting liver transplants at Hospital Israelita Albert Einstein were subject to magnetic resonance, microbubble contrast ultrasound, and excision liver biopsies.

RESULTS

Excellent agreement between magnetic resonance and microbubble contrast ultrasound was observed in this study. There was moderate agreement between both imaging methods and histopathology results.

CONCLUSION

Microbubble contrast ultrasound was as accurate as magnetic resonance to evaluate hepatocellular carcinoma. These results were confirmed by comparing both methods to histopathological diagnosis.

Dynamic enhancing vascular pattern of intrahepatic peripheral cholangiocarcinoma on contrast-enhanced ultrasound: the influence of chronic hepatitis and cirrhosis

PURPOSE

To analyse the dynamic enhancing features by real-time contrast-enhanced ultrasound (CEUS) of intrahepatic peripheral cholangiocarcinoma (ICC) in patients with chronic hepatitis and cirrhosis.

MATERIALS AND METHODS

CEUS was performed by using contrast pulse sequencing (CPS) imaging with mechanical index of <0.2 after injection of 2.4 mL of contrast agent. CEUS images of histologically confirmed ICC in 54 patents (15 patents with chronic hepatitis B, 16 patents with cirrhosis, and 23 patents with normal underlying liver) were analyzed.

RESULTS

Heterogeneous hyperenhancement was more frequently identified in ICC with chronic hepatitis (9 of 15, 60.0%, p = 0.000) and cirrhosis (8 of 16, 50.0%, p = 0.010) than in patients with normal liver (6 of 23, 26.1%) during arterial phase. The majority of ICC in patients with normal liver displayed peripheral hyperenhancement (13 of 23, 56.5%), than in patients with chronic hepatitis (4 of 15, 26.7%, p = 0.000) and cirrhosis (5 of 16, 31.3%, p = 0.001). Intense contrast uptake during the arterial phase (heterogeneous hyperenhancement or global hyperenhancement) followed by washout in venous phases was more frequently displayed in ICC patients with chronic hepatitis (11 of 15, 73.3%, p = 0.000) and in patients with cirrhosis (11 of 16, 68.8%, p = 0.000) than in ICC patients with normal underlying liver (8 of 23, 34.8%).

CONCLUSION

The enhancing vascular pattern of ICC on CEUS in patients with chronic hepatitis and cirrhosis is different from that in ICC without underlying liver disease. The enhancing vascular pattern is indistinguishable from HCC on CEUS in most ICC patients with chronic hepatitis or cirrhosis.

Contrast-enhanced ultrasound in the preoperative, intraoperative and postoperative assessment of liver lesions

The use of contrast agents (CA) with liver ultrasound (US) has gained recently an established role for the diagnosis of various hepatic diseases due to their safety, high versatility and low costs (contrast-enhanced ultrasound: CEUS). The purpose of this review is to provide a state-of-the-art summary of the available evidence for their use in the characterization of focal liver lesions. A published work search was conducted for all preclinical and clinical studies involving CA on hepatic US imaging. CEUS increases the sensitivity for lesion detection and the specificity to differentiate between benign and malignant diseases due to the enhanced visualization of the tumor microcirculation. Results achieved seem at least equivalent to those of spiral computed tomography or magnetic resonance imaging. The association of CA with intraoperative ultrasound has changed the surgical approach in 25% of patients and guarantees complete ablations by a single session in most of them. CEUS provides detailed information about tumor vasculature, improves the preoperative characterization and therefore the therapeutic strategy, and can evaluate the intraoperative completeness of the ablation.

Patterns of appearance and risk of misdiagnosis of intrahepatic cholangiocarcinoma in cirrhosis at contrast enhanced ultrasound

AIM

Primary aim was to validate the percentage of intrahepatic cholangiocarcinomas (ICC) which have a contrast vascular pattern at contrast enhanced ultrasound (CEUS) at risk of misdiagnosis with hepatocellular carcinoma (HCC) and, secondary aim, to verify if any characteristics in the CEUS pattern helps to identify ICC.

METHODS

All ICC on cirrhosis seen in three Italian centres (Bologna, Milan and Pavia) between 2003 and 2011, in which CEUS and at least another imaging technique (CT or MRI) had been performed, were retrospectively identified. Those patients with ICC size comparable to the early HCC stage (Milan criteria, considered as small ICC) were enrolled for this study. The enhancement pattern at CEUS was analysed and compared with CT or MRI.

RESULTS

A total of 25 small ICC made this study group. CEUS was at risk of misdiagnosis of ICC for HCC in a significantly higher number of cases than in CT (performed in 24 ICC) (52% vs. 4.2%, P = 0.009) and MRI (11 ICC) (52% vs. 9.1%, P = 0.02). A different contrast pattern among all techniques was found in 6 of 10 ICC lesions submitted to the three imaging methods. In the arterial phase, ICC lacked global hyperenhacement in approximately 50% of cases at CEUS and the degree of intensity of wash-out in the late phase was marked in 24% of nodules.

CONCLUSIONS

CEUS misdiagnosed as HCC a significantly higher number of ICC lesions in cirrhotic patients than CT and MRI. However, some CEUS contrast features can help suspect ICC, especially in some cases with inconclusive CT or MRI.

Contrast-Enhanced Ultrasound for the differentiation of benign and malignant focal liver lesions: a meta-analysis

BACKGROUND

International guidelines of Ultrasound recommend the performance of contrast-enhanced ultrasound (CEUS) as the first method of choice after conventional ultrasound for the diagnostic work-up of focal liver lesions. However, these recommendations are based on the results of multiple single studies and only few large multicentre studies.

AIMS

The rationale of the present systematic review and meta-analysis was to assess the overall sensitivity and specificity of CEUS for the diagnosis of malignant liver lesions.

METHODS

Literature databases were searched up to March 2012. Inclusion criteria were evaluation of CEUS, assessment of sensitivity and specificity of CEUS for the diagnosis of malignant liver lesions. The meta-analysis was performed using the random-effects model based on the DerSimonian Laird method. Quality analyses were carried out to assess sources of heterogeneity.

RESULTS

A total of 45 studies with 8147 focal liver lesions were included in the analysis. Overall sensitivity and specificity of CEUS for the diagnosis of malignant liver lesions was 93% (95%-CI: 91-95%) and 90% (95%-CI: 88-92%) respectively. Significant heterogeneity was found between studies. However, subanalysis revealed no significant difference when evaluating studies using histology for all liver lesions, when comparing high-quality and low-quality studies, and blinded vs non-blinded studies.

CONCLUSION

The results of this meta-analysis support the international recommendations on CEUS for the diagnostic work-up of focal liver lesions selecting patients who need further diagnostics.

Contrast-enhanced computed tomography and ultrasound-guided liver biopsy to diagnose dysplastic liver nodules in cirrhosis

BACKGROUND

Dysplastic nodules in cirrhosis herald a very high risk of transition to hepatocellular carcinoma. A better understanding of the relationships between dysplastic nodules and hepatocellular carcinoma development may help refining strategies of enhanced follow-up.

METHODS

All consecutive cirrhotics with a histologically proven de novo dysplastic nodule, were retrospectively identified and underwent alternating abdominal ultrasound and contrast-computed tomography every 3 months. An ultrasound-guided liver biopsy was the diagnostic gold standard, whereas surveillance and recall policies were according to current guidelines.

RESULTS

Among 36 patients with dysplastic nodule (21 low-grade, 15 high-grade, 17.4 ± 2.6mm), 17 (47%) showed arterial wash-in, 15 (42%) portal/venous hypodensity whereas 4 (11%) had neither pattern. During 6-128 (median 36) months, 21 patients developed a hepatocellular carcinoma at a rate of 13.8% per year, intranodular=8.7% vs extranodular=7.1% per year. Hepatocellular carcinoma occurred more frequently in high-grade than low-grade dysplastic nodules (32.2% vs 9.3% per year, p=0.0039); the maximum time to hepatocellular carcinoma transformation was 27 months for intranodular vs 67 months for extranodular tumours (p=0.025). No contrast-computed tomography pattern predicted neoplastic transformation of dysplastic nodules.

CONCLUSION

The histological examination of liver nodules in cirrhosis lacking the imaging hallmark of hepatocellular carcinoma improves both prognostication and outcome of surveillance, since it dictates the intensity of the radiological follow-up.

Assessment of early hepatic echinococcus multilocularis infection in rats with real-time contrast-enhanced ultrasonography

The aim of this study was to demonstrate characteristic imaging and accurate evaluation of blood perfusion in early stage of hepatic alveolar echinococcosis (HAE) by contrast-enhanced ultrasonography (CEUS). The early stage of experimentally induced secondary HAE in 45 rats was studied. Thirty-six HAE lesions in 33 rats, confirmed by pathologic examination, were examined by ultrasound (US), color Doppler flow imaging (CDFI) and then CEUS. Thirty-three lesions were found in 30 rats by US, and 30 lesions were detected in 27 rats by CEUS. The sensitivity of US and CEUS was 92% (95% CI 76%-98%) and 82% (95% CI 65%-93%), respectively. US imaging characteristics were categorized into four types: hyperechoic spot (type 1, 45.5%, 15/33), granular hyperechoic spots (type 2, 12.1%, 4/33), hyperechoic lesion (type 3, 30.3%, 10/33) and mixed pattern (type 4, 12.1%, 4/33). CDFI failed to detect blood flow signals in any lesions. CEUS results for 30 lesions showed ring enhancement in the peripheral area during the arterial phase and no filling effect in either the portal or the delayed phase (46.7%, 14/30); ring enhancement combined with central septa enhancement during the arterial phase and portal venous phase (46.7, 14/30), and no enhancement (6.6%, 2/30). The enhanced area, confirmed by pathologic examination, was an inflammatory reaction belt surrounding the lesion. The results of this study suggest that US, with high sensitivity, can be used as a screening method for early HAE lesions in the animal model, while CEUS can be used for displaying the peripheral blood perfusion and vesicle structure.

Intrahepatic cholangiocarcinomas in cirrhosis are hypervascular in comparison with those in normal livers

BACKGROUND AND AIMS

Intrahepatic cholangiocarcinomas (ICCs) are usually adenocarcinomas with fibrotic and hypovascular stroma. Intrahepatic cholangiocarcinomas in cirrhosis and precirrhotic liver (ICC-cirrhosis) are increasingly being diagnosed, and can display hypervascular enhancement resembling a hepatocellular carcinoma on dynamic imaging.

METHODS

In this study using ICC-cirrhosis (71 cases), ICC with non-specific reactive changes (ICC-reactive) (72 cases) and the cholangiocarcinoma component of combined hepatocellular cholangiocarcinoma (HCC-ICC) (30 cases), we tried to compare the tumour vasculature.

RESULTS

It was found that ICC-cirrhosis and the cholangiocarcinoma component of HCC-ICC showed a higher density of arteries and microvessels (1.59 ± 0.58/mm(2) (mean ± SD) and 140 ± 43/mm(2) in ICC-cirrhosis and 1.74 ± 0.67/mm(2) and 131 ± 46/mm(2) in the cholangiocarcinoma component of HCC-ICC) than in ICC-reactive (1.26 ± 0.61/mm(2) and 103 ± 45/mm(2) ). Dynamic computed tomography (CT) and magnetic resonance imaging (MRI) showed that a majority of ICC-cirrhosis displayed strong hypervascular enhancement, whereas one-third of ICC-reactive each showed strong, weak and no or minimal enhancement respectively. The increased vascular density was positively correlated with enhanced arterial phase of dynamic CT and MRI.

CONCLUSION

The density of arteries and microvessels of ICC-cirrhosis was higher than that in ICC-reactive and comparable to that in the cholangiocarcinoma component of HCC-ICC, and the higher density of arteries and microvessels in ICC may be responsible for the hypervascular enhancement of ICC-cirrhosis.

Contrast-enhanced ultrasound in oncology

In patients with known malignant disease, 51% of liver lesions less than 1.5 cm turn out to be benign. Whether the probability of malignancy is high or low, further investigations are often necessary to definitely exclude malignancy. Contrast-enhanced ultrasonography has a prominent role in lesion characterization with a diagnostic accuracy comparable with computed tomography and magnetic resonance imaging. Anti-angiogenic treatment is common in most oncological institutions and the response evaluation is a new challenge with a research focus on the change in tumour vasculature and perfusion. In planning biopsies, CEUS can identify necrotic and viable areas of tumours and improve the diagnostic accuracy.

Real-time contrast-enhanced ultrasonography of resected and immunohistochemically proven hepatic angiomyolipomas

PURPOSE

The purpose of this study was to assess real-time contrast-enhanced ultrasound in patients with hepatic angiomyolipomas with respect to contrast-enhancing kinetics and enhancement patterns.

MATERIALS AND METHODS

Nonlinear, low mechanical index (mechanical index less than 0.2), real-time contrast-enhanced ultrasonography was performed in 18 patients with 19 tumors after 2.4 mL bolus injection of contrast agent SonoVue. All the 19 tumors were surgically resected and immunohistochemically proven sporadic hepatic angiomyolipomas.

RESULTS

Inhomogeneous hyperenhancing pattern was detected 16 tumors (84.2%) and homogeneous hyperenhancing pattern in 1 tumor (0.5%) in arterial phase and portal phase, 16 lesions remained hyperenhancement but one lesion became isoenhancement in late phase. Two lesions (10.5%) were detected inhomogeneously hypoenhancement compared to liver parenchyma during arterial, portal, and late phases, with only punctiform internal enhancement. The margin of all the lesions were smooth and well defined on contrast-enhanced ultrasonography, whereas no peripheral nodular arterial enhancement, centripetal filling, or spoke-wheel like enhancement pattern were depicted. Early strong enhancement in arterial phase, rapid washout of contrast agent, and appear hypoechoic to surrounding liver tissue during portal or late phase was not at all observed.

CONCLUSION

Real-time contrast-enhanced ultrasonography can demonstrate typical imaging characteristics of hepatic angiomyolipomas in most cases, that is, inhomogeneous hyperenhancing pattern in arterial phase, prolonged hyperenhancement during portal and late phase with smooth and well-defined margin. This real-time dynamic imaging technique may therefore improve noninvasive characterization and differentiation of this rare, benign, hepatic mesenchymal neoplasm.

Molecular imaging: current status and emerging strategies

In vivo molecular imaging has a great potential to impact medicine by detecting diseases in early stages (screening), identifying extent of disease, selecting disease- and patient-specific treatment (personalized medicine), applying a directed or targeted therapy, and measuring molecular-specific effects of treatment. Current clinical molecular imaging approaches primarily use positron-emission tomography (PET) or single photon-emission computed tomography (SPECT)-based techniques. In ongoing preclinical research, novel molecular targets of different diseases are identified and, sophisticated and multifunctional contrast agents for imaging these molecular targets are developed along with new technologies and instrumentation for multi-modality molecular imaging. Contrast-enhanced molecular ultrasound (US) with molecularly-targeted contrast microbubbles is explored as a clinically translatable molecular imaging strategy for screening, diagnosing, and monitoring diseases at the molecular level. Optical imaging with fluorescent molecular probes and US imaging with molecularly-targeted microbubbles are attractive strategies as they provide real-time imaging, are relatively inexpensive, produce images with high spatial resolution, and do not involve exposure to ionizing irradiation. Raman spectroscopy/microscopy has emerged as a molecular optical imaging strategy for ultrasensitive detection of multiple biomolecules/biochemicals with both in vivo and ex vivo versatility. Photoacoustic imaging is a hybrid of optical and US techniques involving optically-excitable molecularly-targeted contrast agents and quantitative detection of resulting oscillatory contrast agent movement with US. Current preclinical findings and advances in instrumentation, such as endoscopes and microcatheters, suggest that these molecular imaging methods have numerous potential clinical applications and will be translated into clinical use in the near future.

Molecular ultrasound assessment of tumor angiogenesis

Angiogenesis, the growth of new blood vessels, plays a critical role in progression of tumor growth and metastasis, making it an attractive target for both cancer imaging and therapy. Several molecular markers, including those that are involved in the angiogenesis signaling pathway and those unique to tumor angiogenic vessels, have been identified and can be used as targets for molecular imaging of cancer. With the introduction of ultrasound contrast agents that can be targeted to those molecular markers, targeted contrast-enhanced ultrasound (molecular ultrasound) imaging has become an attractive imaging modality to non-invasively assess tumor angiogenesis at the molecular level. The advantages of molecular ultrasound imaging such as high temporal and spatial resolution, non-invasiveness, real-time imaging, relatively low cost, lack of ionizing irradiation and wide availability among the imaging community will further expand its roles in cancer imaging and drug development both in preclinical research and future clinical applications.

Intrahepatic peripheral cholangiocarcinoma in cirrhosis patients may display a vascular pattern similar to hepatocellular carcinoma on contrast-enhanced ultrasound

The aim of this study was to describe the imaging features by contrast-enhanced ultrasound (CEUS) of intrahepatic cholangiocarcinoma (ICC) in cirrhosis patients. We registered the CEUS images of cirrhosis patients with histologically confirmed ICC. In all cases magnetic resonance imaging (MRI) was done to confirm the diagnosis and/or staging purposes. A total of 21 patients met all the criteria to be included in the study. The median nodule size was 32 mm. All nodules showed contrast enhancement at arterial phase; in 10 cases it was homogeneous and in 11 cases peripheral (rim-like). All nodules displayed washout during the venous phases; it appeared during the first 60 seconds in 10 nodules, between 60-120 seconds in five cases, and in six cases after 2 minutes. Ten nodules (five larger than 2 cm) displayed homogeneous contrast uptake followed by washout and they correspond to the specific pattern of hepatocellular carcinoma according to the American Association for the Study of Liver Diseases criteria. However, none of these lesions displayed washout on MRI.

CONCLUSION

CEUS should not be used as the sole imaging technique for conclusive hepatocellular carcinoma diagnosis and if the MRI does not display the diagnostic vascular pattern, a confirmatory biopsy is mandatory.

Characterization of focal liver lesions with SonoVue®-enhanced sonography: International multicenter-study in comparison to CT and MRI

AIM: To evaluate in a multicenter study whether the sonographic characterization of focal liver lesions can be improved using SonoVue®-enhancement; and to compare this method with computed tomography (CT) and magnetic resonance imaging (MRI).

METHODS: One hundred and thirty four patients with one focal liver lesion detected in baseline ultrasound (US) were examined with conventional US, contrast-enhanced US (n = 134), contrast-enhanced CT (n = 115) and/or dynamic contrast-enhanced MRI (n = 70). The lesions were classified as malignant, benign or indeterminate and the type of lesion was determined. The final diagnosis based on the combined information of all imaging examinations, clinical information and histology (n = 32) was used. Comparisons were made to see whether the addition of contrast-enhanced US led to the improvement of the characterization of doubtful focal liver lesions.

RESULTS: In comparison with unenhanced US, SonoVue® markedly improves sensitivity and specificity for the characterization (malignant/benign) of focal liver lesions. In comparison with CT and/or dynamic MRI, SonoVue®-enhanced sonography applied for characterization of focal liver lesions was 30.2% more sensitive in the recognition of malignancy and 16.1% more specific in the exclusion of malignancy and overall 22.9% more accurate. In the subgroup with confirmative histology available (n = 30), sensitivity was 95.5% (CEUS), 72.2% (CT) and 81.8% (MRI), and specificity was 75.0% (CEUS), 37.5% (CT) and 42.9% (MRI). The sensitivity and specificity of CEUS for the identification of focal nodular hyperplasia (FNH) and hemangiomas was 100% and 87%, resulting in an accuracy of 94.5%.

CONCLUSION: SonoVue®-enhanced sonography emerges as the most sensitive, most specific and thus most accurate imaging modality for the characterization of focal liver lesions.

Detection of colo-rectal liver metastases: prospective comparison of contrast enhanced US, multidetector CT, PET/CT, and 1.5 Tesla MR with extracellular and reticulo-endothelial cell specific contrast agents

BACKGROUND

To compare contrast-enhanced US (CE-US), multidetector-CT (MDCT), 1.5 Tesla MR with extra-cellular (Gd-enhanced) and intracellular (SPIO-enhanced) contrast agents and PET/CT, in the detection of hepatic metastases from colorectal cancer.

MATERIALS AND METHODS

A total of 34 patients with colo-rectal adenocarcinoma underwent preoperatively CE-US, MDCT, Gd- and SPIO-enhanced MR imaging (MRI), and PET/CT. Each set of images was reviewed independently by two blinded observers. The ROC method was used to analyze the results, which were correlated with surgical findings, intraoperative US, histopathology, and MDCT follow-up.

RESULTS

A total of 57 hepatic lesions were identified: 11 hemangiomas, 29 cysts, 1 focal fatty liver, 16 metastases (dimensional distribution: 5/16 < 5 mm; 3/16 between 5 mm and <10 mm; 8/16 ≥ 10 mm). Six of 34 patients were classified as positive for the presence of at least one metastasis. Considering all the metastases and those ≥ 10 mm, ROC areas showed no significant differences between Gd- and SPIO-enhanced MRI, which performed significantly better than the other modalities (P < 0.05). Considering the lesions <10 mm, ROC areas showed no significant differences between all modalities; however MRI presented a trend to perform better than the other techniques. Considering the patients, ROC areas showed no significant differences between all the modalities; however PET/CT seemed to perform better than the others.

CONCLUSIONS

Gd- and SPIO-enhanced MRI seem to be the most accurate modality in the identification of liver metastases from colo-rectal carcinoma. PET/CT shows a trend to perform better than the other modalities in the identification of patients with liver metastases.

[Real-time contrast-enhanced ultrasound in the evaluation of focal liver lesions: diagnostic efficacy and economical issues from a French multicentric study]

The recent introduction of high-end ultrasound equipment combined with recent contrast agents provides marked improvements in the characterization of focal liver lesions as previously reported by monocentric studies. The aim of the present study was to evaluate the diagnostic performance of Contrast-Enhanced Ultrasonography (CEUS) using SonoVue as well as its medico-economic value for characterization of focal liver lesions. These nodules were not characterized on previous CT or conventional sonography. This prospective multicentric study conducted in 15 French centres found diagnostic performances similar to those reported for CT and MRI, with a concordance rate of 84.5%, sensitivity greater than 80% and specificity greater than 90% for all types of lesions. Higher acceptance was found for CEUS compared to other imaging modalities. Economical assessment based on examination reimbursment and contrast agent cost showed a lower cost for contrast ultrasound versus CT and MRI. This French multicentric study confirmed the high diagnostic value of CEUS for focal liver lesion characterization and demonstrated a lower economical impact compared to other imaging modalities such as CT and 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.

A case of well-differentiated cholangiolocellular carcinoma visualized with contrast-enhanced ultrasonography using Sonazoid

We here report the first case of cholangiolocellular carcinoma (CoCC) visualized with contrast-enhanced ultrasonography (CEUS) using a second-generation contrast agent, Sonazoid. A 76-year-old man was admitted to our hospital for evaluation of a hepatic tumor. The tumor was described as having hyper-enhancement in the early phase and persistent enhancement in the late phase by contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI), as well as hypervascularity by angiography. CEUS assessment of the nodule showed diffuse and homogeneous enhancement in the pure arterial phase, which became progressively hypoechoic relative to the adjacent liver parenchyma during the portal vein and late phases (mixed vascular phase), and showed a contrast defect with an unclear border in the Kupffer phase. Histologically we diagnosed this hepatic tumor as CoCC. In light of the above findings and the rarity of CoCC, it is helpful to incorporate the results of several imagings, such as CT, MRI, angiography and CEUS with a second-generation contrast agent when clinically diagnosing CoCC.

Small liver lesions in oncologic patients: characterization with CT, MRI and contrast-enhanced US

Focal liver lesions (FLLs) are frequently discovered during ultrasound examinations either in healthy subjects without a clinical history of cancer or during staging or follow-up procedures in oncologic patients or in routine surveillance of hepatopathic patients. In oncologic patients, the liver is the most common target of metastatic disease and accurate detection and characterisation of FLLs is prognostically fundamental during the initial staging as well as before and after pre-operative chemotherapy, as it can help to identify patients who are most likely to benefit from liver surgery. Moreover, early detection of primary or secondary liver malignancies increases the possibility of curative surgical resection or successful percutaneous ablation. As many FLLs in these patients are benign, a precise and preferably non-invasive method of differentiation from malignant metastatic nodules is needed. Moreover, the continuous follow-up of cancer patients requires an easily available, reliable and cost-effective diagnostic tool for the detection and characterization of FLLs.

Diagnostic approaches for cholangiocarcinoma

Cholangiocarcinomas arise from the epithelial cells of the bile ducts and are associated with poor prognosis. Despite new diagnostic approaches, the definite diagnosis of this malignancy continues to be challenging. Cholangiocarcinomas often grow longitudinally along the bile duct rather than in a radial direction. Thus, large tumor masses are frequently absent and imaging techniques, including ultrasound, CT, and MRI have only limited sensitivity. Tissue collection during endoscopic (ERCP) and/or percutaneous transhepatic (PTC) procedures are usually used to confirm a definitive diagnosis of cholangiocarcinoma. However, forceps biopsy and brush cytology provide positive results for malignancy in about only 50% of patients. Percutaneous and peroral cholangioscopy using fiber-optic techniques were therefore developed for direct visualization of the biliary tree, yielding additional information about endoscopic appearance and tumor extension, as well as a guided biopsy acquistion. Finally, endoscopic ultrasonography (EUS) complements endoscopic and percutaneous approaches and may provide a tissue diagnosis of tumors in the biliary region through fine-needle aspiration. In the future, new techniques allowing for early detection, including molecular markers, should be developed to improve the diagnostic sensitivity in this increasing tumor entity.

The impact of 18F-FDG PET/CT in patients with liver metastases

PURPOSE

The aim of this study was to assess the performance of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) versus dedicated contrast-enhanced CT (CECT) in the detection of metastatic liver disease.

METHODS

All patients that presented to our Institution with suspected metastatic liver disease who underwent (18)F-FDG PET/CT and CECT within 6 weeks of each other, were retrospectively analyzed, covering a 5-year period. One hundred and thirty-one patients (67 men, 64 women; mean age 62) were identified. Seventy-five had colorectal carcinoma and 56 had other malignancies. The performance of CECT and that of (18)F-FDG-PET/CT in detecting liver metastases were compared. The ability of each to detect local recurrence, extrahepatic metastases and to alter patient management was recorded. The final diagnosis was based on histology, clinical and radiological follow-up (mean 23 months).

RESULTS

In detecting hepatic metastases, (18)F-FDG-PET/CT yielded 96% sensitivity and 75% specificity, whilst CECT showed 88% sensitivity and 25% specificity. (18)F-FDG-PET/CT and CECT were concordant in 102 out of 131 patients (78%). In the colorectal group (18)F-FDG-PET/CT showed 94% sensitivity and 75% specificity, whilst CECT had 91% sensitivity and 25% specificity. In the noncolorectal group (18)F-FDG-PET/CT showed 98% sensitivity and 75% specificity whilst CECT had 85% sensitivity and 25% specificity. Overall, (18)F-FDG-PET/CT altered patient management over CECT in 25% of patients. CECT did not alter patient management over (18)F-FDG-PET/CT alone in any patients.

CONCLUSION

(18)F-FDG-PET/CT performed better in detecting metastatic liver disease than CECT in both colorectal and noncolorectal malignancies, and frequently altered patient management. The future role of CECT in these patients may need to be re-evaluated to avoid potentially unnecessary duplication of investigation where (18)F-PET/CT is readily available.

A revolution in liver ultrasound

Liver ultrasound has been revolutionized by the development of microbubble contrast agents and multipulse software designed to detect their nonlinear resonances. The ability to visualize all parts of the liver's vasculature, including the sinusoids, at high spatial and temporal resolution gives unique insights into the haemodynamics of focal liver lesions. It has enabled ultrasound to detect and, as described by Celli N, et al.Eur J Gastroenterol Hepatol 2007; 3-14, to characterize such lesions with an accuracy comparable to multidetector computed tomography with consequent improvements in patient handling.