Benefits of contrast-enhanced sonography for the detection of liver lesions: comparison with histologic findings. AJR Am J Roentgenol. 2008;190:683-690. [PMID: 18287439 DOI: 10.2214/AJR.07.2295]

Contrast-Enhanced Ultrasound Guidance for Interventional Procedures

Since its introduction, contrast-enhanced ultrasound (CEUS) has gained an important role in the diagnosis and management of abdominal and pelvic diseases. Contrast-enhanced ultrasound can improve lesion detection rates as well as success rates of interventional procedures when compared to conventional ultrasound alone. Additionally, CEUS enables the interventionalist to assess the dynamic enhancement of different tissues and lesions, without the adverse effects of contrast-enhanced computed tomography, such as exposure to ionizing radiation and nephrotoxicity from iodinated contrast material. This review article describes the various applications and advantages of the use of CEUS to enhance performance of ultrasound-guided interventions in the abdomen and pelvis.

SIUMB guidelines and recommendations for the correct use of ultrasound in the management of patients with focal liver disease

The present document describes the SIUMB (Italian Society of Ultrasound in Medicine and Biology) guidelines for the use of ultrasound in the management of focal liver disease. The aim of the paper is to provide a clinical practice guideline for Italian physicians who are approaching the ultrasound study of a focal liver lesion. In particular, these guidelines provide simple indications, recommendations and general practice advices for the correct use of contrast-enhanced ultrasound (CEUS) in this scenario. They represent the SIUMB position of the ultrasound role in the diagnostic flow charts of the principal focal liver lesions, and are in agreement with other, previously published national and international guidelines.

Time-intensity curve analysis of contrast-enhanced ultrasound is unable to differentiate renal dysfunction in the early post-transplant period - a prospective study

Background

Contrast enhanced ultrasonography (CEUS) assessment of kidney allografts mainly focuses on graft rejection. However, studies on delayed graft function (DGF) without acute rejection are still lacking. The aim of this study was to build a time-intensity curve (TIC) using CEUS in non-immunological DGF to understand the utility of CEUS in early transplantation.

Methods

Twenty-eight patients in the short-term postoperative period (<14 days) were divided according to the need for dialysis (early graft function [EGF] and [DGF]) and 37 subjects with longer than 90 days follow-up were divided into creatinine tertiles. Time to peak [TTP] and rising time [RT were compared between groups.

Results

EGF and DGF were similar, except for creatinine. In comparison to the late group, medullary TTP and RT were shorter in the early group as well as the delay regarding contrast arrival in the medulla (in relation to cortex) and reaching the medullary peak (in relation to artery and cortex). In the late group, patients with renal dysfunction showed shorter temporal difference to reach medullary peak in relation to artery and cortex.

Conclusions

Although it was not possible to differentiate EGF and DGF using TIC, differences between early and late groups point to blood shunting in renal dysfunction.

Contribution of 3-Dimensional Contrast-Enhanced Ultrasonography (CEUS) Compared With 2-Dimensional CEUS in the Analysis of Liver Tumors

OBJECTIVES

In this study, we investigated the vascular characteristics of liver tumors on 3-dimensional (3D) and 2-dimensional (2D) contrast-enhanced ultrasonography (CEUS). The clinical value of these CEUS methods in the diagnosis of benign and malignant liver tumors was evaluated and compared.

METHODS

A total of 126 liver tumors were examined by conventional ultrasonography (US), 2D CEUS, and dynamic 3D CEUS (frequency range, 1-6 MHz; focusing ability, 2-25 cm in depth; mechanical index, 0.09). Dynamic 3D CEUS images were postprocessed with high-resolution intelligent tomographic technology. The sensitivity and specificity of the CEUS methods in differentiating benign and malignant liver tumors were compared, as were the vascular characteristics (including the number and spatial relationships of the tumor vessels, such as origin and continuity) of the tumors in the arterial phase.

RESULTS

The imaging methods did not significantly differ in their sensitivity and specificity for differentiating benign and malignant liver tumors (P > .05). Dynamic 3D CEUS was significantly better than 2D CEUS in revealing the vascular characteristics of the tumors (P < .05). The vascular morphologic characteristics of benign and malignant hepatic tumors in the arterial phase of dynamic 3D CEUS using intelligent tomographic technology differed significantly (P < .05).

CONCLUSIONS

Dynamic 3D CEUS of liver tumors provides a more intuitive and comprehensive view of the spatial relationships of their blood vessels, including their peripheral and internal distribution. The volume information obtained with dynamic 3D CEUS combined with intelligent tomographic technology can improve the US-based diagnosis of liver tumors and thus guide their 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.

Management of disappearing lesions after chemotherapy for colorectal liver metastases: Relation between detectability and residual tumors

BACKGROUND AND OBJECTIVES

To clarify the detectability of gadolinium ethoxybenzyl diethylene-triamine pantaacetic acid enhanced magnetic resonance imaging (EOB-MRI) and contrast-enhanced intraoperative-ultrasonography (CE-IOUS) for residual disease in disappearing colorectal liver metastases (DLMs) and to seek a better management for DLMs.

METHODS

Eighty-two patients who underwent hepatectomy after chemotherapy for colorectal liver metastases were retrospectively reviewed. Lesions which disappear on post-chemotherapy contrast-enhance CT were defined as DLMs. All the patients underwent EOB-MRI and CE-IOUS. With pathologic evaluation for resected specimens and clinical observation of anatomically corresponding site for non-resected lesions, detectability of residual disease in DLMs were estimated between these two imaging modalities.

RESULTS

Twenty (18%) patients presented with 111 DLMs, and EOB-MRI and CE-IOUS identified 64 (57.6%) and 62 (55.9%), respectively. Residual disease was pathologically confirmed for 69.2% in resected specimens and clinically estimated in 33.3% for non-resected DLMs. EOB-MRI showed a higher accuracy of prediction of residual disease compared with CE-IOUS (0.90 vs 0.70). Of the 11 non-resected lesions which were undetected with CE-IOUS and regrew after surgery, 9 (81.8%) were detected on EOB-MRI.

CONCLUSIONS

EOB-MRI may be superior to CE-IOUS in detecting residual tumors for DLMs. Maximum attempt of resection would be needed for visualized lesions in EOB-MRI.

Centralization of Liver Cancer Surgery and Impact on Multidisciplinary Teams Working on Stage IV Colorectal Cancer

Surgical resection is the most effective treatment approach for colorectal liver metastases but only a minority of patients is suitable for upfront surgery. The treatment strategies of stage IV colorectal cancer have shifted towards a continuum of care in which medical and surgical treatment combinations are tailored to the clinical setting of the individual patient. The optimization of treatment through appropriate decision-making and multimodal therapy for stage IV colorectal cancer require a joint multidisciplinary meeting in a centralized liver cancer unit.

Real-time contrast-enhanced sonographically guided biopsy or radiofrequency ablation of focal liver lesions using perflurobutane microbubbles (sonazoid): value of Kupffer-phase imaging

OBJECTIVES

To evaluate the utility of Kupffer-phase imaging by real-time contrast-enhanced sonography using the perflurobutane microbubble contrast agent Sonazoid (GE Healthcare, Oslo, Norway) in guiding biopsy or radiofrequency (RF) ablation of focal liver lesions.

METHODS

A total of 75 patients (mean age, 59.7 years) who were referred for percutaneous biopsy (n = 42) or RF ablation (n = 33) were included in the study. Grayscale sonography and contrast-enhanced sonography using Sonazoid were performed in all patients before the procedure. The conspicuity of each targeted liver lesion on grayscale sonography, vascular-phase contrast-enhanced sonography, and Kupffer-phase contrast-enhanced sonography was graded using a 5-point scale. Lesion detection rates were calculated, and the conspicuity of the lesions among the imaging modalities was compared. The technical success of the procedures was also assessed.

RESULTS

The procedures were conducted in 66 patients (biopsy in 41 and RF ablation in 25) under real-time guidance by Kupffer-phase contrast-enhanced sonography. Lesion detection rates were 77.3% (58 of 75), 84.0% (63 of 75), and 92.0% (69 of 75) on grayscale sonography, vascular-phase contrast-enhanced sonography, and Kupffer-phase contrast-enhanced sonography, respectively, and were significantly different among the 3 modalities (P= .034). Overall, lesion conspicuity was significantly increased on vascular-phase and Kupffer-phase contrast-enhanced sonography compared to grayscale sonography (P < .001). Technical success rates for the procedures were 95.2% (40 of 42) for biopsy and 69.7% (23 of 33) for RF ablation.

CONCLUSIONS

Kupffer-phase imaging by contrast-enhanced sonography using Sonazoid increases the conspicuity of the liver lesions compared to grayscale sonography, and it is useful for real-time guidance of percutaneous biopsy or RF ablation of focal liver lesions.

Value of contrast-enhanced ultrasound in assessing differentiation degree and pathological type of small hepatocellular carcinoma

AIM: To investigate the value of contrast-enhanced ultrasonography (CEUS) in assessing differentiation degree and pathological type of small hepatocellular carcinoma (SHCC).

METHODS: Ninety SHCC lesions examined by CEUS were retrospectively analyzed. The enhancement time and patterns were compared and analyzed according to the differentiation degree and pathological type of SHCC.

RESULTS: Of the 90 lesions, 48 had high differentiation, 30 had moderate differentiation, and 12 had low differentiation; 56 were trabecular type, 16 glandular type, 11 compact type and 7 cirrhotic type. Compared with patients with moderate or low differentiation lesions, those with high differentiation lesions showed significantly longer washout time (P = 0.000, P = 0.006). In the portal venous and late phases, the enhancement patterns showed statistically significant differences among lesions with different differentiation degrees (P = 0.000): compared with patients with moderate and high differentiation lesions, those with lower differentiation lesions showed a significantly higher rate of hypoechoic nodules and fast wash-in and wash-out enhancement pattern (P < 0.05). The difference of washout time was statistically significant among pathological types of SHCC (P = 0.021). Compared with the trabecular (100.12 s ± 33.00 s) and glandular types (98.98 s ± 30.20 s), the washout time was significantly shorter for the compact type (66.20 s ± 10.54 s). In the portal venous and late phases, the difference of enhancement patterns was statistically significant among pathological types of SHCC (P = 0.000, P = 0.000). In the trabecular, glandular and compact types, 77%, 75%, and 100% of lesions exhibited a fast wash-in and wash-out enhancement pattern, respectively. However, for the cirrhotic type, all lesions exhibited a fast wash-in and slow wash-out enhancement pattern.

CONCLUSION: CEUS may provide valuable information for assessing differentiation degree and histopathologic type of SHCC. More studies are needed to provide more evidence.

The surgical treatment of patients with colorectal cancer and liver metastases in the setting of the "liver first" approach

A surgical resection is the only curative method in the therapy of colorectal carcinoma and liver metastases. Along with the development of interventional radiological techniques the indications for surgery widen. The number of metastases and patients age should not present a contraindication for surgical resection. However, there are still some doubts concerns what to resect first in cases of synchronous colorectal carcinoma and liver metastases and how to ensure the proper remnant liver volume in order to avoid postoperative liver failure and achieve the best results. Through this review the surgical therapy of colorectal carcinoma and liver metastases was revised in the setting of "liver-first" approach and the problem of ensuring of remnant liver volume.

Intraoperative contrast-enhanced sonographic portography combined with indigo carmine dye injection for anatomic liver resection in hepatocellular carcinoma: a new technique

We present a method of intraoperative contrast-enhanced sonographic portography combined with indigo carmine dye injection for anatomic liver resection in hepatocellular carcinoma. During surgery, before dye infusion into the feeding portal vein, the targeted portal vein branch was directly punctured, and a microbubble contrast agent was administered under sonographic guidance. Simultaneous enhancement of the resected hepatic parenchyma with a microbubble contrast agent and blue dye improved estimation of the segmental border in the cutting plane and the tumor resection margin during liver surgery.

Dual-mode registration of dynamic contrast-enhanced ultrasound combining tissue and contrast sequences

This study proposes a new method for automatic, iterative image registration in the context of dynamic contrast-enhanced ultrasound (DCE-US) imaging. By constructing a cost function of image registration using a combination of the tissue and contrast-microbubble responses, this new method, referred to as dual-mode registration, performs alignment based on both tissue and vascular structures. Data from five focal liver lesions (FLLs) were used for the evaluation. Automatic registration based on the dual-mode registration technique and tissue-mode registration obtained using the linear response image sequence alone were compared to manual alignment of the sequence by an expert. Comparison of the maximum distance between the transformations applied by the automatic registration techniques and those from expert manual registration reference showed that the dual-mode registration provided better precision than the tissue-mode registration for all cases. The reduction of maximum distance ranged from 0.25 to 9.3mm. Dual-mode registration is also significantly better than tissue-mode registration for the five sequences with p-values lower than 0.03. The improved sequence alignment is also demonstrated visually by comparison of images from the sequences and the video playbacks of the motion-corrected sequences. This new registration technique better maintains a selected region of interest (ROI) within a fixed position of the image plane throughout the DCE-US sequence. This should reduce motion-related variability of the echo-power estimations and, thus, contribute to more robust perfusion quantification with DCE-US.

Comparison of contrast-enhanced ultrasonography with grey-scale ultrasonography and contrast-enhanced computed tomography in diagnosing focal fatty liver infiltrations and focal fatty sparing

PURPOSE

Fatty liver infiltrations and fatty sparing impair diagnostic performance of grey-scale ultrasonography in differentiating malignant and benign focal liver lesions. In the study, we present our experience in diagnosing focal fatty liver infiltrations and focal fatty sparing with contrastenhanced ultrasonography (CEUS) in comparison to grey-scale ultrasonography and contrast-enhanced computed tomography (CECT).

MATERIAL AND METHOD

The retrospective study group (n=82 patients), included 44 (53.7%) men, 38 (46.3%) women (aged 29- 81 years, mean 55.8 years) with 48 focal fatty liver infiltrations and 34 focal fatty sparing. All patients underwent grey-scale ultrasonography (US), CEUS using SonoVue® and CECT executed within the 7 days.

RESULTS

With US, CEUS and CECT focal fatty liver infiltrations were diagnosed in 22, 46 and 44 cases, respectively. The following values were obtained: sensitivity - 45.8%, 95.8% and 91.7%, specificity - 100% for all, accuracy - 95.2%, 99.6% and 99.3%, respectively. Focal fatty sparing was diagnosed in 16, 31 and 30 cases, respectively. The following values were obtained: sensitivity - 47.1%, 91.2% and 88.2%, specificity - 99.8%, 100% and 100%, accuracy - 95.6%, 99.4% and 99.3%, respectively. No statistically significant differences were found in sensitivity of diagnosing focal fatty liver infiltrations and focal fatty liver sparing between CEUS and CECT. Sensitivity of grey-scale ultrasonography was significantly lower when compared to those of CEUS and CECT (p<0.001).

CONCLUSION

CEUS is as sensitive as CECT in focal fatty infiltrations and focal fatty sparing diagnosing. However, CEUS provides more information than CECT about the vasculature and enhancement pattern of focal fatty liver infiltrations.

Comparison of percutaneous cryoablation with microwave ablation in a porcine liver model

We compared imaging and pathological changes between argon-helium cryosurgical (AH) and microwave (MW) ablation in a porcine liver model. Immediately after ablation, computed tomography (CT) imaging showed that the area affected by MW ablation was considerably greater than that affected by AH ablation; moreover, the surface area of necrotic tissue was considerably greater in the AH group, whereas the depth of the necrotic area was similar. Seven days after ablation, the affected area had not changed much in the AH group, but it had significantly increased in the MW group; similarly, the surface and depth of the necrotic areas had not changed much in the AH group, but they had increased significantly in the MW group. The pathological findings showed similar definitive areas for both groups at both time points. The findings indicated that long time after both therapies, complete tissue necrosis can be achieved, but the extent and depth of necrosis differ: necrosis foci after AH ablation could be predicted by ice ball under CT image, and necrosis foci after MW ablation will increase obviously. MW ablation might therefore be suitable for tumors with a larger volume and simple anatomical structures, and AH ablation might be suitable for tumors with complex anatomical structures or those located near important organs. These two methods could therefore be used in combination in clinical settings, but details of the procedure need to be studied.

Fusion imaging-guided percutaneous biopsy of focal hepatic lesions with poor conspicuity on conventional sonography

OBJECTIVES

The purpose of this study was to evaluate the effectiveness of real-time fusion imaging (sonography combined with computed tomography or magnetic resonance imaging) for percutaneous sonographically guided biopsy of focal hepatic lesions with poor sonographic conspicuity.

METHODS

This study was conducted as a retrospective analysis of a prospective database and was approved by the Institutional Review Board. Patients who had target lesions with poor conspicuity on B-mode sonography for percutaneous biopsy were enrolled in the study. Lesion conspicuity was assessed by conventional B-mode sonography first and then by fusion imaging later in the same session. We compared lesion conspicuity and detection rates between B-mode sonography and fusion imaging and evaluated how many cases of initially invisible lesions on B-mode sonography became visible on fusion imaging. The technical success rate was evaluated on the basis of the final diagnoses, which were established by pathologic examination of the biopsy specimens as well as follow-up clinical and radiologic examinations.

RESULTS

A total of 22 patients were enrolled in the study. On fusion imaging, lesion conspicuity was increased in 63.6% of focal hepatic lesions (14 of 22). Moreover, 66.7% of lesions (6 of 9) that were invisible on B-mode sonography became visible on fusion imaging. The true-positive detection rate was significantly different between B-mode sonography and fusion imaging (9 of 22 versus 19 of 22; P = .0044). Percutaneous biopsy was performed for all lesions, including 3 target lesions that were invisible even on fusion imaging. The technical success rate was 95.5% (21 of 22).

CONCLUSIONS

Fusion imaging is effective for percutaneous biopsy of focal hepatic lesions with poor sonographic conspicuity.

What is the optimal neo-adjuvant treatment for liver metastasis?

Colorectal cancer is the third most common cancer in the Western population and has a 5-year overall survival of 5-10% when metastatic. Approximately 30% of the patients with metastatic colorectal cancer have limited disease apparently isolated to the liver and, if this can be resected, the 5-year overall survival is improved to 30-60%. Therefore, it is important to identify patients who have both resectable disease and those with initially unresectable tumors who can potentially be downsized with chemotherapy to allow resection. First-line doublet chemotherapy regimens lead to response rates of 50-60%, triplet chemotherapy regimens may result in a response rate of up to 70%, and biological agents may add to responses or induce morphologic changes that facilitate disease resection. Surgical advances in recent years have also increased resectability rates and have challenged prior rules of resectability. Local therapies including ablation and radiation, often performed in conjunction with resection, may further aid in control of disease. The aim of this article is to focus on the role of neoadjuvant therapy in the treatment of colorectal liver metastases.

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.

Selection for hepatic resection of colorectal liver metastases: expert consensus statement

Hepatic resection offers a chance of a cure in selected patients with colorectal liver metastases (CLM). To achieve adequate patient selection and curative surgery, (i) precise assessment of the extent of disease, (ii) sensitive criteria for chemotherapy effect, (iii) adequate decision making in surgical indication and (iv) an optimal surgical approach for pre-treated tumours are required. For assessment of the extent of the disease, contrast-enhanced computed tomography (CT) and/or magnetic resonance imaging (MRI) with gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) is recommended depending on the local expertise and availability. Positron emission tomography (PET) and PET/CT may offer additive information in detecting extrahepatic disease. The RECIST criteria are a reasonable method to evaluate the effect of chemotherapy. However, they are imperfect in predicting a pathological response in the era of modern systemic therapy with biological agents. The assessment of radiographical morphological changes is a better surrogate of the pathological response and survival especially in the patients treated with bevacizumab. Resectability of CLM is dependent on both anatomic and oncological factors. To decrease the surgical risk, a sufficient volume of liver remnant with adequate blood perfusion and biliary drainage is required according to the degree of histopathological injury of the underlying liver. Portal vein embolization is sometimes required to decrease the surgical risk in a patient with small future liver remnant volume. As a complete radiological response does not signify a complete pathological response, liver resection should include all the site of a tumour detected prior to systemic treatment.

Guidelines and good clinical practice recommendations for Contrast Enhanced Ultrasound (CEUS) in the liver - update 2012: A WFUMB-EFSUMB initiative in cooperation with representatives of AFSUMB, AIUM, ASUM, FLAUS and ICUS

Initially, a set of guidelines for the use of ultrasound contrast agents was published in 2004 dealing only with liver applications. A second edition of the guidelines in 2008 reflected changes in the available contrast agents and updated the guidelines for the liver, as well as implementing some non-liver applications. Time has moved on, and the need for international guidelines on the use of CEUS in the liver has become apparent. The present document describes the third iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS) using contrast specific imaging techniques. This joint WFUMB-EFSUMB initiative has implicated experts from major leading ultrasound societies worldwide. These liver CEUS guidelines are simultaneously published in the official journals of both organizing federations (i.e., Ultrasound in Medicine and Biology for WFUMB and Ultraschall in der Medizin/European Journal of Ultrasound for EFSUMB). These guidelines and recommendations provide general advice on the use of all currently clinically available ultrasound contrast agents (UCA). They are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis and improve the management of patients worldwide.

The oncosurgery approach to managing liver metastases from colorectal cancer: a multidisciplinary international consensus

An international panel of multidisciplinary experts convened to develop recommendations for the management of patients with liver metastases from colorectal cancer (CRC). The aim was to address the main issues facing the CRC hepatobiliary multidisciplinary team (MDT) when managing such patients and to standardize the treatment patients receive in different centers. Based on current evidence, the group agreed on a number of issues including the following: (a) the primary aim of treatment is achieving a long disease-free survival (DFS) interval following resection; (b) assessment of resectability should be performed with high-quality cross-sectional imaging, staging the liver with magnetic resonance imaging and/or abdominal computed tomography (CT), depending on local expertise, staging extrahepatic disease with thoracic and pelvic CT, and, in selected cases, fluorodeoxyglucose positron emission tomography with ultrasound (preferably contrast-enhanced ultrasound) for intraoperative staging; (c) optimal first-line chemotherapy-doublet or triplet chemotherapy regimens combined with targeted therapy-is advisable in potentially resectable patients; (d) in this situation, at least four courses of first-line chemotherapy should be given, with assessment of tumor response every 2 months; (e) response assessed by the Response Evaluation Criteria in Solid Tumors (conventional chemotherapy) or nonsize-based morphological changes (antiangiogenic agents) is clearly correlated with outcome; no imaging technique is currently able to accurately diagnose complete pathological response but high-quality imaging is crucial for patient management; (f) the duration of chemotherapy should be as short as possible and resection achieved as soon as technically possible in the absence of tumor progression; (g) the number of metastases or patient age should not be an absolute contraindication to surgery combined with chemotherapy; (h) for synchronous metastases, it is not advisable to undertake major hepatic surgery during surgery for removal of the primary CRC; the reverse surgical approach (liver first) produces as good an outcome as the conventional approach in selected cases; (i) for patients with resectable liver metastases from CRC, perioperative chemotherapy may be associated with a modestly better DFS outcome; and (j) whether initially resectable or unresectable, cure or at least a long survival duration is possible after complete resection of the metastases, and MDT treatment is essential for improving clinical and survival outcomes. The group proposed a new system to classify initial unresectability based on technical and oncological contraindications.

Semiquantitative strain elastography of liver masses

OBJECTIVES

This study was designed to determine the utility of semiquantitative strain elastography in differential diagnosis of solid liver masses.

METHODS

A total of 103 patients with focal liver masses underwent abdominal sonographic examinations and freehand elastography of focal hepatic lesions. Eighty-two patients (79.7%) with 93 focal hepatic lesions were included in the study. Twenty-one patients (20.3%) were excluded from the study because of technical limitations of semi-quantitative strain elastography and difficulty in detection of normal liver parenchyma on gray-scale sonography. We evaluated different focal hepatic lesions such as hemangiomas, focal nodular hyperplasia, nodular regenerative hyperplasia, adenomas, hepatocellular carcinomas, metastases, and cholangiocarcinomas. The stiffness of the lesions was determined by measurement of strain values on semiquantitative strain elastography. The strain index value (strain ratio of liver parenchyma and focal lesions) of each lesion was calculated. Mean strain index values of benign and malignant liver lesions were compared.

RESULTS

The mean strain index value of malignant liver lesions ± SD (2.82 ± 1.82) was significantly higher than that of benign liver lesions (1.45 ± 1.28; P< .0001). Hemangiomas had a significantly lower mean strain index value than other benign lesions (P < .0034). There was no statistically significant difference between strain index values of different types of malignant lesions (P > .05).

CONCLUSIONS

Semiquantitative strain elastography may be helpful for differentiating benign and malignant liver masses. The substantial overlap between strain index values of benign and malignant liver masses limits clinical usefulness of this technique.

Contrast-enhanced ultrasound in abdominal imaging

The administration of a contrast agent is considered an essential tool to evaluate abdominal diseases using Ultrasound. The most targeted organ is the liver, especially to characterize focal liver lesions and to assess the response to percutaneous treatment. However, the expanding abdominal indications of contrast-enhanced ultrasound make this technique an important tool in the assessment of organ perfusion including the evaluation of ischemic, traumatic, and inflammatory diseases.

Current and potential renal applications of contrast-enhanced ultrasound

The combination of microbubble technology and complementary ultrasound techniques has resulted in the development of contrast-enhanced ultrasound (CEUS) and, although initial clinical applications largely focussed on the liver, these are now becoming more diverse. With regard to the kidney, it is a safe, well-tolerated, and reproducible technique, and in selected cases, can obviate the need for computed tomography or magnetic resonance imaging. A clear advantage is the absence of nephrotoxicity. With respect to the current and potential renal applications, it is a useful technique in the evaluation of pseudotumours, acute pyelonephritis, renal tumours, cystic lesions, vascular insults, and renal transplantation. It may also be of value for monitoring the kidney following anti-angiogenic treatment or nephron-sparing interventional techniques for renal tumours. Assessment of microvascular perfusion using time-intensity curves is also likely to have further far-reaching applications in the kidney as well as other organs.

[Detection and characterization of liver metastases]

Since the advent of second generation ultrasound (US) contrast agents, ultrasound has caught up with other imaging modalities for the detection and characterization of liver metastases and as a result of its high temporal and spatial resolution it can in some cases even be superior to computed tomography (CT) and magnetic resonance imaging (MRI). Many studies have demonstrated a sensitivity and specificity of over 90%. Due to its high temporal resolution contrast-enhanced US (CEUS) is capable of detecting even a very short duration of hyper-enhancement during the arterial phase. Radiation protection and lack of adverse effects on renal or thyroid function are additional arguments why CEUS should be recommended as the first imaging modality in the evaluation of hepatic metastases in cases of favorable scanning conditions.

Short-term evaluation of liver tumors after transarterial chemoembolization: limitations and feasibility of contrast-enhanced ultrasonography

PURPOSE

To evaluate the limitations and the feasibility of contrast-enhanced ultrasonography (CEUS) for the assessment of tumor response shortly after transarterial chemoembolization (TACE).

MATERIALS AND METHODS

Fifty seven patients (41 patients with hepatomas, 16 patients with metastases) were studied with CEUS before, 1 day after, and 30 days after TACE. A CEUS-efficiency score (CEUS-ES) was calculated, which evaluated: (a) the completeness of visualization of the target tumor(s) (2: good, 1: adequate, 0: poor) and (b) the quality of delineation of post-TACE necroses (2: good, 1: adequate, 0: poor). A CEUS study was considered as "diagnostic," if each of the aforementioned parameters was associated with grade 1 or 2.

RESULTS

CEUS studies were "diagnostic" in 36/57 patients (63.1%). Patients with hepatomas were more likely to undergo "diagnostic" CEUS than patients with metastases (70.7% vs. 43.7%, P = 0.0728). Lesions' multiplicity, deep location, hypoenhancement on pretreatment CEUS, and diffuse growth had a statistically significant (P < 0.05) negative impact on CEUS-ES. Hyperechogenicity on pre-treatment, unenhanced US had a non-statistically significant (P = 0.176) negative impact. Differences between "diagnostic" CEUS studies and CT/MR regarding detection of residual tumor were insignificant (P = 0.8178).

CONCLUSION

The percentage of lesions which are unsuitable for post-TACE evaluation with CEUS is not negligible. For the rest, the respective role of CEUS is promising.

Screening for liver metastases in women with mammary carcinoma: comparison of contrast-enhanced ultrasound and magnetic resonance imaging

OBJECTIVE

The objective of the present study was to compare conventional B-mode ultrasound (BMU), contrast-enhanced ultrasound (CEUS), and magnetic resonance imaging (MRI) in the detection of liver metastases at the primary staging and follow-up of women with histologically confirmed mammary carcinoma.

PATIENTS AND METHODS

Included in the study were 55 women (aged 57.5 ± 11.0 years, range 27-75 years; mean disease duration 57.5 months, range 5-168 months); of these, 17 women were examined as part of primary staging (staging group) and 38 women at follow-up (follow-up group). All patients underwent BMU (Philips HDI 5000), CEUS (Philips HDI 5000; 4.8 ml SonoVue), and MRI (Siemens Avanto 1.5 T) of the liver.

RESULTS

In the staging group (n = 17), a mass was detected by BMU in 24% (n = 4), by CEUS in 29% (n = 5), and by MRI in 47% (n = 8); masses suspicious for malignancy were identified in 6% of patients with BMU and in 12% each by CEUS and MRI. Malignancy was not confirmed in any case by cytology or surgery. In the follow-up group (n = 38), masses were identified by MRI in 53% of patients with suspicion of malignancy in 18%. Malignancy was confirmed in 16% of cases identified at MRI, in 13% of cases identified with CEUS, and in 11% of cases identified with BMU. The Pearson coefficients of correlation were r = .29 (P = .03) for MRI vs. BMU; r = .42 (P = .002) for MRI vs. CEUS; and r = .75 (P ≤ .001) for BMU vs. CEUS. With respect to malignancy, the Pearson coefficients of correlation were r = .40 (P = .099) for BMU vs. MRI and r = .71 (P = .0009) for CEUS vs. MRI.

CONCLUSIONS

Beginning in tumor stage III, the use of CEUS and MRI is associated with a significantly greater benefit in the detection of malignant tumors of the liver compared with conventional BMU. BMU appears to be adequate for primary staging and the follow-up of lower tumor stages.

Sonographically guided transthoracic biopsy of peripheral lung and mediastinal lesions: role of contrast-enhanced sonography

OBJECTIVES

The purpose of this study was to assess the impact of contrast-enhanced sonography on sonographically guided transthoracic needle biopsy of lung lesions.

METHODS

A total of 121 patients underwent sonographically guided transthoracic needle cutting biopsy. Of the 121 patients, 62 (contrast-enhanced sonography group) underwent contrast-enhanced sonography before biopsy, and the information from contrast-enhanced sonography was used to optimize the biopsy procedure. The remaining 59 patients constituted the non-contrast-enhanced sonography group. The enhancement patterns and echogenicity were evaluated by the consensus of 2 sonographers. The diagnostic efficacy was compared between the contrast-enhanced and non-contrast-enhanced sonography groups.

RESULTS

The enhancement intensity and extent varied greatly among different thoracic lesions, and an anechoic area (necrosis) was revealed in 26 of 62 lesions (41.9%) lesions after administration of the contrast agent. The overall diagnostic accuracy of sonographically guided transthoracic biopsy in this study was 85.9% (104 of 121). In the contrast-enhanced sonography group, the initial biopsy led to correct diagnosis in 58 of 62 lesions (93.6%). In the non-contrast-enhanced sonography group, the initial biopsy led to correct diagnosis in 46 of 59 lesions (78.0%). The difference in the diagnostic accuracy between the contrast-enhanced and non-contrast-enhanced sonography groups was statistically significant (P < .05).

CONCLUSIONS

Contrast-enhanced sonography enables differentiation of viable from necrotic portions of thoracic lesions and has a positive impact on the diagnostic efficacy of sonographically guided transthoracic needle biopsy.

Evaluation of focal hepatic lesions with ultrasound contrast agents

Ultrasound contrast agents have gained wide acceptance for the detection and characterization of focal liver lesions. This pictorial essay reviews the growing body of evidence that supports the use of modern ultrasound contrast agents and illustrates the enhancement characteristics of commonly encountered focal liver lesions. Pathologies discussed include metastases, hepatocellular carcinomas, focal nodular hyperplasia, hepatocellular adenomas, hemangiomas, abscesses, complex cysts, and focal fatty deposition.

Diagnosis value of focal liver lesions with SonoVue®-enhanced ultrasound compared with contrast-enhanced computed tomography and contrast-enhanced MRI: a meta-analysis

PURPOSES

This study is aimed at evaluating diagnostic value of focal liver lesions (FLLs) with SonoVue(®)-enhanced ultrasound compared with contrast-enhanced computed tomography (CECT) and contrast-enhanced magnetic resonance imaging (CEMRI).

METHODS

PubMed, EMBASE, and the Cochrane Central Register were searched for English language articles published from January 2000 to May 2011. Histopathologic analysis and/or close clinical and imaging follow-up (except CECT or CEMRI) for at least 6 months were used as golden reference. Sensitivity, specificity, summary receiver operating characteristic (SROC) curves, and area under the curve (AUC) were extracted to test heterogeneity.

RESULTS

In 21 included studies, for the SonoVue(®)-enhanced ultrasound studies, sensitivity was 88% (95% CI 87-90), specificity was 81% (95% CI 79-84), and 38.62 (95% CI 13.64-109.35) for diagnostic odds ratio (DOR); for the CECT studies, sensitivity was 90% (95% CI 88-92), specificity was 77% (95% CI 71-82), and 30.84 (95% CI 11.11-85.61) for DOR; for the CEMRI studies, sensitivity was 86% (95% CI 83-88), specificity was 81% (95% CI 76-85), and 27.63 (95% CI 11.28-67.70) for DOR.

CONCLUSIONS

In comparison, SonoVue(®)-enhanced ultrasound had high pooled sensitivity and pooled specificity. SROC analysis showed the diagnostic value of FLLs with SonoVue(®)-enhanced ultrasound has no significant difference compared with CECT and CEMRI. SonoVue(®)-enhanced ultrasound is highly sensitive and specific in the characterization of FLLs to support an effective diagnostic method.

Contrast-enhanced ultrasound-guided microwave ablation for hepatocellular carcinoma inconspicuous on conventional ultrasound

OBJECTIVE

To evaluate the efficiency and feasibility of contrast-enhanced ultrasound (CEUS)-guided microwave ablation for hepatocellular carcinoma inconspicuous on conventional US.

MATERIALS AND METHODS

From March 2006 to February 2010, 107 patients (93 male, 14 female; mean age 58.9±11.0 years) with 107 hepatocellular carcinoma (HCC) nodules (mean maximum diameter 19.5±8.5 mm) inconspicuous on conventional US underwent microwave (MW) ablation under CEUS guidance in this study. US contrast agent was SonoVue (Bracco, Milan, Italy), a second-generation contrast agent. CEUS was performed first, and then MW ablation was carried out by means of CEUS guidance under unconscious intravenous anaesthesia if the tumours were displayed on CEUS.

RESULTS

105 tumours were successfully visualised on CEUS by using 1-2 times contrast agent injection and MW ablation was performed under CEUS guidance. The technical success rate was 98.13% (105/107). The number of antenna insertions for each tumour was 1.89±0.92, and the mean session of MW ablation for each tumour was 1.08±0.28. The mean duration of energy application for each tumour was 7.05±4.03 min. The follow-up time was 12-54 months (median 18 months). The technique effectiveness rate was 99.05% (104/105). The local tumour progression rate was 1.9% (2/105). There were no severe complications in any patients.

CONCLUSION

CEUS-guided MW ablation is an efficient and feasible treatment method for patients with hepatocellular carcinoma inconspicuous on conventional US.

Contrast-enhanced ultrasound for surveillance of choroidal carcinoma patients: features of liver metastasis arising several years after treatment of the primary tumor

Choroidal carcinoma is an insidious tumor frequently causing late liver metastases which are associated with a poor outcome. Since metastatic liver lesions are potentially resectable with curative intention, tight follow-up schedules after treatment of primary tumors for the early detection of liver metastasis have been proposed. The methods employed so far, however, have proven to be of limited sensitivity, and it is likely that a combined approach comprising the use of both imaging techniques and biohumoral markers will, in the future, improve the sensitivity of methods aiming at detecting liver metastasis early. Contrast-enhanced ultrasound (CEUS) is increasingly used in the clinic due to its advantage over conventional sonography for the early detection of tumor lesions and thus represents a promising accurate and cost-effective diagnostic tool. Its use for the early diagnosis of metastatic choroidal cancer has never been proposed before in the literature. Here, we describe for the first time the CEUS features of a large liver metastasis originating from choroidal cancer occurring 13 years after diagnosis in comparison to PET-CT, MRI and conventional sonography. Furthermore, we propose CEUS as a routine follow-up method for the early detection of liver metastasis of patients affected by choroidal carcinoma.

Diagnostic value of contrast-enhanced ultrasound, computed tomography and magnetic resonance imaging for focal liver lesions: a meta-analysis

The diagnostic performance of contrast-enhanced ultrasound (CEUS), contrast-enhanced computed tomography (CECT) and contrast-enhanced magnetic resonance imaging (CEMRI) was determined in patients with focal liver lesions (FLLs) in a meta-analysis. Meta-Disc version 1.4 was used to describe and calculate sensitivity, specificity, summary receiver operating characteristic (SROC) curves and area under the curve (AUC). In the 25 included studies, the pooled estimate of CEUS studies for sensitivity, specificity and diagnostic odds ratio (DOR) was 87% (95% CI 85-88), 89% (95% CI 87-91) and 78.84 (95% CI 29.40-211.40), respectively. Sensitivity, specificity and DOR were 86% (95% CI 84-88), 82% (95% CI 77-86) and 26.34 (95% CI 8.32-83.39), respectively, for the CECT studies. Sensitivity, specificity and DOR were 85% (95% CI 82-88), 87% (95% CI 83-91) and 48.37 (95% CI 15.87-147.45), respectively, for the CEMRI studies. SROC analysis indicated that the diagnostic value of CEUS for FLLs is not significantly different from that of CECT and CEMRI.

Contrast-enhanced ultrasound of the spleen: an introduction and pictorial essay

A wide variety of pathologies can produce focal lesions within the spleen. These are being more frequently encountered as imaging technology improves. It is vital that radiologists are aware of these pathologies to enable accurate diagnosis. The role of ultrasound contrast in splenic disease will be discussed and illustrated with cases likely to be encountered by general and abdominal radiologists.

Liver metastases: Sulphur hexafluoride-enhanced ultrasonography for lesion detection: a systematic review

This is a systematic review to evaluate the accuracy of contrast-enhanced ultrasonography (CEUS) performed with "SonoVue" (sulphur hexafluoride) in the detection of hepatic metastases. The MEDLINE, EMBASE and COCHRANE Databases were searched, regardless of language, for relevant articles published before December 2009. Two reviewers independently assessed study eligibility using a standardized form and methodological quality using the quality assessment of diagnostic accuracy studies (QUADAS) Checklist. Sensitivity estimates were calculated on a per-patient and/or per-lesion basis. The search for published articles yielded 718 potentially relevant abstracts. Of these, 14 papers were eligible but only three articles fulfilled the inclusion criteria, which comprised a total of 450 patients (patient sample number: range 12 to 365; cancer prevalence: 14.8 to 71.2%). Estimated per-patient sensitivity ranged from 79-100%. Although the quality assessment of diagnostic accuracy studies checklist showed the papers were of good quality, a meta-analysis was not applicable because of the lack of eligible studies. In conclusion, CEUS seems to be promising in the detection of liver metastases; however, there have not been enough studies to conduct meta-analysis. Further studies are required before this promising method can be widely used.

Laparoscopic ultrasound: a survey of its current and future use, requirements, and integration with navigation technology

BACKGROUND

Laparoscopic ultrasound (LUS) increases surgical safety by allowing the surgeon to see beyond the organ surface, by visualizing vascular structures and by improving surgical precision of tumor resection. A questionnaire-based survey was used to investigate the current use and future expectations of LUS technology.

METHODS

A questionnaire consisting of 26 questions was distributed manually at four different conferences (60% at the European Association for Endoscopic Surgery (EAES) conference, Stockholm 2008). The answers were summarized with descriptive statistics and nonparametric tests at a significance level of 0.05.

RESULTS

The questionnaire was answered by 177 surgeons from 40 different countries (85% from Europe). Of these surgeons, 43% use ultrasound during laparoscopic procedures. Generally, more LUS users are found at university hospitals than at general community hospitals. Surgeons use LUS primarily in procedures related to the liver (67% of the surgeons who use LUS), but LUS also is used in other procedures related to the pancreas, biliary tract, and colon. In a 5-year perspective, 82% of surgeons believe in an increased use of LUS, and 79% of surgeons also think that the use of LUS combined with navigation technology will increase and that the most important requirements for such a system are good image quality, easy interpretation, and a high degree of precision.

CONCLUSIONS

Although the surgeons believe LUS has advantages, only 43% of the respondents reported using it. The surveyed surgeons were largely positive toward an increased use of LUS in a 5-year perspective and believe that LUS combined with navigation technology will contribute to improving the surgical precision of tumor resection.

The nodular form of hepatic tuberculosis: contrast-enhanced ultrasonographic findings with pathologic correlation

OBJECTIVE

The purposes of this study were to describe the ultrasonographic findings in hepatic tuberculosis (TB) after administration of a second-generation sulfur hexafluoride-filled microbubble contrast agent and to correlate these findings with pathologic characteristics.

METHODS

Twenty-four hepatic TB lesions in 15 patients were studied with conventional ultrasonography (CUS) and contrast-enhanced ultrasonography (CEUS). Pathologic characteristics of the lesions were evaluated and were then correlated with enhancement patterns.

RESULTS

The appearance of hepatic TB on CUS was variable and nonspecific with respect to the shape, echogenicity, and boundary of the lesions. The diameters of the lesions obtained from CEUS were statistically larger than those from CUS, with largest diameters +/- SD of 4.2 +/- 1.8 and 3.1 +/- 1.9 cm, respectively. During the arterial phase, 13 of 24 lesions (54.2%) showed a rapidly and markedly enhanced rim with a hypoenhanced or nonenhanced center; 9 of 24 lesions (37.5%) showed transient enhancement of the whole lesion with inconsistent intensities. During the portal phase, most lesions showed distinct wash-out of the contrast agent and maintained a hypoechoic appearance. Pathologic studies confirmed that the different appearances of hepatic TB on CEUS were related to the different pathologic stages of the lesions.

CONCLUSIONS

Findings of hepatic TB on CEUS may be helpful in differentiating the diagnosis from other hepatic focal lesions. Correlation with pathologic findings would enrich the understanding of CEUS findings in hepatic TB.

Radiofrequency ablation guided by contrast harmonic sonography using perfluorocarbon microbubbles (Sonazoid) for hepatic malignancies: an initial experience

AIM

Conventional contrast harmonic sonography has the technical problem of a short enhancement time during targeting of hepatic malignancies for radiofrequency (RF) ablation. This study investigated the effectiveness of contrast harmonic sonographic guidance using perfluorocarbon microbubbles (Sonazoid) during RF ablation of hepatic malignancies.

MATERIALS AND METHODS

Nodules were detected on contrast-enhanced computed tomography, but could not be resolved clearly by B-mode sonography. Sixty-six patients (51 men, 15 women; mean age, 65.8 years) with 108 hepatic malignancies were enrolled. Fifty-one patients with hepatocellular carcinoma and 15 patients with liver metastases were treated by RF ablation guided by contrast harmonic sonography using perfluorocarbon microbubbles for a target lesion identified as a defect image after the administration of contrast medium.

RESULTS

The maximal diameters of all tumours ranged from 0.7 to 3.5 cm (mean +/- SD, 1.7 cm +/- 0.9) on sonography. Complete tumour necrosis was achieved by a single session of RF ablation in 62 (94%) of the 66 patients, while two sessions were required for the remaining four (6%) patients. The average number of treatment sessions was 1.1 +/- 0.3. In the post-vascular phase, 105 (97%) of a total of 108 malignant hepatic tumours were depicted as a defect with a margin. Clinical courses have been satisfactory without any signs of local tumour progression during 1-12 months of follow-up (mean, 4.3 months).

CONCLUSION

Using perfluorocarbon microbubbles, contrast harmonic sonographic-guided RF ablation is an efficient approach for guiding further ablation of hepatic malignancies that are not clearly demarcated by B-mode sonography.

Real-time contrast-enhanced ultrasound-guided biopsy of focal hepatic lesions not localised on B-mode ultrasound

OBJECTIVE

To prospectively evaluate the technical feasibility of percutaneous real-time contrast-enhanced ultrasound (CEUS) guided biopsy of focal hepatic lesions that are not confidently localised on B-mode US.

METHODS

The study included 44 patients (mean age, 61.3 years) whose biopsy target could not be confidently localised on B-mode US performed by two independent radiologists. Biopsy was attempted under the guidance of both CEUS and B-mode US simultaneously displayed on a single monitor. Final diagnosis was established based on the pathological examination of the biopsy specimen as well as on clinical and radiological follow-up.

RESULTS

The size and depth of the target lesions were 18.0 +/- 9.0 mm (mean +/- SD) and 41.8 +/- 17.2 mm respectively. Five patients with negative or indistinct CEUS findings did not undergo biopsy, while 39 patients completed the biopsy. In 38 of the 39 patients, the biopsy result was concordant with the final diagnosis. In the remaining one patient, the biopsy failed to prove metastasis. As there were six cases of technical failure, the technical success rate was 86% (38/44). The sensitivity in diagnosing malignancy was 88% (30/34).

CONCLUSION

Real-time CEUS-guided biopsy is technically feasible for hepatic focal lesions that are not confidently localised on B-mode US.

Improved detection of hepatic metastases with contrast-enhanced low mechanical-index pulse inversion ultrasonography during the liver-specific phase of sonazoid: observer performance study with JAFROC analysis

RATIONALE AND OBJECTIVES

To compare B-mode ultrasonography (US) alone with the combination of B-mode and contrast-enhanced (Sonazoid) late-phase pulse-inversion US for the detection of hepatic metastases by use of jackknife free-response receiver-operating characteristic (JAFROC) analysis.

MATERIALS AND METHODS

Twenty-seven patients with 57 hepatic metastases and 6 patients without hepatic metastases underwent B-mode and contrast-enhanced US. We used the diagnoses established by contrast-enhanced computed tomography and contrast-enhanced US as the standard of reference. All ultrasonographic scanning was performed by an experienced radiologist with a routine clinical procedure. All scanning data were archived with digital cine clips. A review system, which can display pairs of cine clips for B-mode and contrast-enhanced US side by side, was developed for off-site observer study. Seven radiologists interpreted each case individually first by B-mode US only, and then by the combination with contrast-enhanced US by identifying locations of possible candidates for hepatic metastasis with their confidence ratings. The figure-of-merit (FOM) values, sensitivity, and false-positives per case were estimated for B-mode US alone, and for the combination of B-mode and contrast-enhanced US.

RESULTS

The sensitivities of the combined ultrasonographic imaging (mean, 72.2%) were clearly improved from that of B-mode US alone (mean, 41.6%) while reducing the average number of false positives from 1.1 to 0.5 per case. In the jackknife analysis, there was a statistically significant difference between mean FOM values for the combined imaging (0.76) and for B-mode US alone (0.44, P < .00001).

CONCLUSION

Evaluating cine clips of contrast-enhanced liver US together with B-mode US could improve physicians' accuracy for detection of hepatic metastases.