Focal liver lesions: role of contrast-enhanced ultrasound

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.

Instant evaluation of contrast enhanced endoscopic ultrasound helps to differentiate various solid pancreatic lesions in daily routine

BACKGROUND

Contrast enhanced harmonic endoscopic ultrasound (CEH-EUS) is a spreading technique; some studies have shown its value in the diagnosis of pancreatic adenocarcinoma using quantitative analysis.

AIM

To examine the value of CEH-EUS for differentiating various pancreatic lesions in everyday routine with qualitative and quantitative analysis.

METHODS

Data of 55 patients with pancreatic lesions who underwent CEH-EUS were analysed retrospectively. Perfusion characteristics were classified by the investigator qualitatively immediately upon investigation, quantitative analysis was performed later on. Samples from fine needle aspiration (EUS-FNA) or surgical specimen served as gold standard.

RESULTS

CEH-EUS showed 39 hypoenhanced lesions, 3 non-enhanced and 13 hyperenhanced lesions. Concordance of the investigators qualitative classification of peak contrast enhancement with quantitative analysis later on was 100%, while other parameters such as arrival time, time to peak or area under the curve did not show additional value. 34 of 39 hypoenhanced lesions were pancreatic adenocarcinoma; of the hyperenhanced lesions 4 were inflammatory, 3 neuroendocrine carcinomas, 1 lymphoma, 1 insulinoma and 4 metastases (2 of renal cell carcinoma, 2 of lung cancer). Non-enhanced lesions showed up as necroses. Sensitivity for the detection of pancreatic adenocarcinoma was 100%, specificity 87.2% for hypoenhancement alone; in otherwise healthy pancreatic tissue all hypoenhanced lesions were pancreatic adenocarcinoma (sensitivity and specificity 100%, PPV and NPV for adenocarcinoma 100%).

CONCLUSION

This study again shows the excellent value of CEH-EUS in everyday routine for diagnostics of various focal pancreatic lesions suggesting that qualitatively assessed hypoenhancement is highly predictive for adenocarcinoma. Additional quantitative analysis of perfusion parameters does not add diagnostic yield. In case of the various hyperenhanced pancreatic lesions in our data set, histologic sampling is essential for further treatment.

Histology-Based Assessment of Sonazoid-Enhanced Ultrasonography for the Diagnosis of Liver Metastasis

This retrospective study aimed to assess the diagnostic performance of contrast-enhanced ultrasound with Sonazoid (S-CEUS) for liver metastasis. We enrolled in this study 98 patients with 148 histologically proven liver lesions, with 121 metastases and 27 non-metastases. The S-CEUS technique showed sensitivity in 95.0% (115 of 121), specificity in 44.4% (12 of 27) and accuracy in 85.8% (127 of 148) for the diagnosis of metastasis. Higher body mass index had a negative influence on the positive predictive value and accuracy, and a greater depth of the lesion had a negative influence on the accuracy. The management was changed in 8 patients (8.2%) because of S-CEUS findings. In conclusion, the addition of S-CEUS may offer a great benefit by improvement of the quality of diagnosis and management for patients with cancer who have a tentative diagnosis of liver metastasis by contrast-enhanced computed tomography.

Contrast-enhanced ultrasound in the diagnosis of orbital space-occupying lesions

AIM

To summarise the sonographic findings and assess the feasibility of contrast-enhanced ultrasound (CEUS) as an imaging method for the diagnosis of orbital space-occupying lesions.

MATERIALS AND METHODS

This was a prospective study of 53 patients who underwent orbital ultrasound at Xijing Hospital. Two-dimensional ultrasound, colour Doppler flow imaging (CDFI), and CEUS imaging were obtained and compared in patients with orbital haemangioma, pseudotumour, melanoma of the choroid, and retinoblastoma.

RESULTS

CEUS imaging cannot only visualise the location, shape, border, acoustic properties of a lesion, and interactions between the lesion and surrounding tissues, but also display the microvasculature and tissue perfusion within the lesion. The information obtained from CEUS imaging is valuable for diagnosis and differential diagnosis of orbital space-occupying lesions.

CONCLUSION

CEUS imaging allowed better visualisation of the lesions, enabled detection of vascular changes, increased the signal-to-noise ratio, and increased the sensitivity of detection of changes in perfusion in the microcirculation. It has relatively high sensitivity and specificity in the diagnosis of orbital space-occupying lesions and increases the accuracy of diagnosis.

Ultrasound in the management of pleural disease

INTRODUCTION

Pleural disease encompasses a large range of conditions, is a common presentation to the acute medical take and often requires comprehensive investigation and treatment. Ultrasound is well recognised as a useful investigative tool in pleural disease especially in the field of pleural effusion, pleural thickening and interventional procedures. Thoracic ultrasound (TUS) has gained widespread use by physicians as evidence has shown a reduced rate of complications when performing pleural procedures with ultrasound guidance. Areas covered: This article will review studies assessing the role of TUS in the management of pleural disease and examine ongoing research into how TUS could advance our knowledge and understanding over the next decade. Expert commentary: Physician lead thoracic ultrasound has become commonplace over the last decade, and now represents a minimum standard of safety in conducting the majority of 'bedside' pleural procedures. The current evidence points to important diagnostic and procedural roles of the use of bedside thoracic ultrasound. In the future, research developments are likely to lead to the use of thoracic ultrasound in prognostication, targeted treatment and understanding pathogenesis in pleural disease.

Impact of Modified Anisotropic Diffusion-based Enhancement Method in Computer-Aided Classification of Focal Liver Lesions

This work is presented with the objective to assess quantitatively the impact of modified anisotropic diffusion-based enhancement method of Mittal et al. in computer-aided classification of focal liver lesions. This assessment was made before and after enhancement of clinically acquired ultrasound images with the comparison of (a) discrimination capability of radiologically important texture contrast feature using box plot and p-value statistics and (b) test results of designed computer-aided classification schemes to detect/classify focal liver tissues using receiver operating characteristic curves. The results reveal that the application of enhancement method on clinically acquired ultrasound image may effectively improve the confidence of clinicians/radiologists in computer-aided diagnostic solutions to detect and classify focal liver lesions.

Visualization of Small-Diameter Vessels by Reduction of Incoherent Reverberation With Coherent Flow Power Doppler

Power Doppler (PD) imaging is a widely used technique for flow detection. Despite the wide use of Doppler ultrasound, limitations exist in the ability of Doppler ultrasound to assess slow flow in the small-diameter vasculature, such as the maternal spiral arteries and fetal villous arteries of the placenta and focal liver lesions. The sensitivity of PD in small vessel detection is limited by the low signal produced by slow flow and the noise associated with small vessels. The noise sources include electronic noise, stationary or slowly moving tissue clutter, reverberation clutter, and off-axis scattering from tissue, among others. In order to provide more sensitive detection of slow flow in small diameter vessels, a coherent flow imaging technique, termed coherent flow PD (CFPD), is characterized and evaluated with simulation, flow phantom experiment studies, and an in vivo animal small vessel detection study. CFPD imaging was introduced as a technique to detect slow blood flow. It has been demonstrated to detect slow flow below the detection threshold of conventional PD imaging using identical pulse sequences and filter parameters. In this paper, we compare CFPD with PD in the detection of blood flow in small-diameter vessels. The results from the study suggest that CFPD is able to provide a 7.5-12.5-dB increase in the signal-to-noise ratio (SNR) over PD images for the same physiological conditions and is less susceptible to reverberation clutter and thermal noise. Due to the increase in SNR, CFPD is able to detect small vessels in high channel noise cases, for which PD was unable to generate enough contrast to observe the vessel.

Contrast-Enhanced Sonographic Characteristics of Hepatic Inflammatory Pseudotumors

A hepatic inflammatory pseudotumor, which can be misdiagnosed as a malignant tumor, is a relatively uncommon tumor with nonspecific imaging manifestations. As a new diagnostic technique, contrast-enhanced sonography has become increasingly important in the diagnosis of liver focal lesions. Here we present 3 cases of histologically confirmed hepatic inflammatory pseudotumors diagnosed with contrast-enhanced sonography. "Fast-in and centrifugal-out" may be a characteristic contrast-enhanced sonographic enhancement pattern in the diagnosis of hepatic inflammatory pseudotumors, which needs confirmation in further studies.

The diagnostic value of endoscopic ultrasonography and contrast-enhanced harmonic endoscopic ultrasonography in gastrointestinal stromal tumors

Objective:

To evaluate the diagnostic value of endoscopic ultrasonography (EUS) and contrast-enhanced harmonic (CEH) EUS in patients with gastrointestinal stromal tumors (GISTs).

Patients and Methods:

About 19 patients with suspected GISTs underwent EUS and CEH-EUS before tumor resection. The malignant potential was assessed according to the modified Fletcher classification system. Patients were divided into lower (Group I) and higher (Group II) malignant potential group. The clinical characteristics and EUS/CEH-EUS features were compared between two groups.

Results:

The tumor size in Group II was significantly larger than that in Group I (14.6 ± 5.8 mm vs. 32.1 ± 8.4 mm, P < 0.05). Heterogeneous echogenicity was observed in 4 (4/8) cases in Group II and none in Group I (P < 0.05). Irregular intratumoral vessels were detected in 6 cases in Group II and none in Group I (P < 0.05). The sensitivity and specificity of irregular vessel detection for discriminating higher from lower malignant potential GISTs were 75% and 100%, respectively. The positive predictive value and negative predictive value of detection of irregular vessels to high malignant potential GISTs were 33% and 100%, respectively.

Conclusion:

Detection of irregular intratumoral vessels can predict higher malignant potential before tumor resection. The tumor size and echogenicity are assistant factors for malignant potential assessment. Endoscopic resection is an efficacious treatment with good security for appropriate patients.

Hepatic filling rate of a microbubble agent: a novel predictor of long-term outcomes in patients with cirrhosis

The aim of the study described here was to evaluate the significance of the hepatic filling rate of a perflubutane microbubble agent in predicting long-term outcomes and prognoses in 32 patients with cirrhosis (37-76 y, 20 females, Child-Pugh A16, B16). The time from delivery of the contrast agent to the hepatic artery to maximum enhancement of the liver parenchyma on the sonogram was defined as the hepatic filling rate (mean = 18.6 s). Hepatic filling rate did not correlate significantly with the Child-Pugh score or the model for end-stage liver disease score. However, the survival rate was lower (93.3% at 1 y, 60.2% at 3 y) and the rate of occurrence of hepatocellular carcinoma (HCC) was higher (13.3% at 1 y, 33.3% at 3 y) in the group with the slow filling rate (≥18 s) than in the group with the rapid filling rate (<18 s) (93.3% at 1 and 3 y for survival, 6.3% at 1 and 3 y for HCC occurrence). Hepatic filling rate may constitute a non-invasive marker for the occurrence of HCC and prognosis of cirrhosis.

Diagnostic performance of contrast-enhanced sonography and acoustic radiation force impulse imaging in solid liver lesions

OBJECTIVES

The purpose of this study was to evaluate the diagnostic performance of contrast-enhanced sonography and acoustic radiation force impulse imaging (ARFI) in differential diagnosis of benign and malignant liver lesions.

METHODS

A total of 156 patients with liver lesions were included in the study. The images from conventional sonography and contrast-enhanced sonography and the shear wave velocity values of the liver lesions were obtained. The diagnostic performance of conventional sonography, contrast-enhanced sonography, and ARFI was assessed by using pathologic examination (needle biopsy or surgery) or clinical imaging inspection as the reference standard.

RESULTS

The sensitivity and specificity of conventional sonography for malignant liver lesions were 57.1% and 43.1%, respectively, and the sensitivity and specificity of ARFI were 81.3% and 74.1%. When using contrast-enhanced sonography for the diagnosis of malignant liver lesions, the sensitivity and specificity were 92.9% and 89.7%. The sensitivity and specificity of contrast-enhanced sonography were significantly higher than those of ARFI and conventional sonography (P < .05).

CONCLUSIONS

The differential diagnostic performance of contrast-enhanced sonography is most predictive of malignant liver lesions. Contrast-enhanced sonography and ARFI have complementary effects in the differential diagnosis of benign and malignant liver lesions.

Natural history of postvascular-phase iso-enhanced lesions on the sonogram in chronic liver diseases

BACKGROUND AND AIM

This study examined the natural history of postvascular-phase iso-enhanced lesions (PIELs) on contrast-enhanced sonograms to determine the potential risk and predictive factors for developing hepatocellular carcinoma (HCC) in chronic liver diseases.

METHODS

This prospective study included 87 PIELs on contrast-enhanced sonograms (postvascular-phase: 10 min post-injection of perflubutane microbubbles) in 72 patients with chronic liver diseases (45 males and 27 females; age 65.0 ± 10.8y; PIEL diameter 12.5 ± 4.2 mm). The PIELs were followed up by ultrasound/contrast-enhanced ultrasound, computed tomography, or magnetic resonance imaging at 3 to 6 months intervals.

RESULTS

Twenty patients developed HCCs during the study period (median, 22.0 months). The cumulative risk of HCC occurrence was 7.9% at 1 year and 36.0% at 3 years. The presence of coexistent HCC (hazard ratio [HR], 4.975; 95% confidence interval [CI], 1.729-14.316; P = 0.003) and alpha-fetoprotein > 20 ng/mL (HR, 4.104; 95% CI, 1.621-10.392; P = 0.003) were significant factors for the risk of HCC occurrence. Fourteen of these lesions were diagnosed as HCCs that developed from iso-enhanced lesions. Cumulative HCC occurrence rates from PIEL > 14 mm was 23.5% at 1 year and 46.3% at 3 years. Cox regression analysis showed that PIEL > 14 mm (HR, 6.780; 95% CI, 2.060-22.32; P = 0.002) and alpha-fetoprotein > 20 ng/mL (HR, 4.892; 95% CI, 1.559-15.350; P = 0.007) were statistically significant factors for HCC occurrence.

CONCLUSIONS

Patients with coexistent HCC, alpha-fetoprotein > 20 ng/mL, or PIEL > 14 mm should be carefully monitored because of the high potential for HCC occurrence.

Contrast ultrasound in hepatocellular carcinoma at a tertiary liver center: First Indian experience

AIM: To assess the role of contrast enhanced ultrasonography in evaluation of hepatocellular carcinoma (HCC) at the first Indian tertiary liver center.

METHODS: Retrospective analysis of contrast enhanced ultrasound (CEUS) examinations over 24 mo for diagnosis, surveillance, characterization and follow up of 50 patients in the context of HCC was performed. The source and indication of referrals, change in referral rate, accuracy and usefulness of CEUS in a tertiary liver center equipped with a 64 slice dual energy computer tomography (CT) and 3 tesla magnetic resonance imaging (MRI) were studied. Sonovue (BR1, Bracco, Italy, a second generation contrast agent) was used for contrast US studies. Contrast enhanced CT/MRI or both were performed in all patients. The findings were taken as a baseline reference and correlation was done with respect to contrast US. Contrast enhanced MRI was performed using hepatocyte specific gadobenate dimeglumine (Gd-BOPTA). Iomeron (400 mg; w/v) was used for dynamic CT examinations.

RESULTS: About 20 (40%) of the examinations were referred from clinicians for characterization of a mass from previous imaging. About 15 (30%) were performed for surveillance in chronic liver disease; 5 (10%) examinations were performed for monitoring lesions after radiofrequency ablation (RFA); 3 (6%) were post trans-arterial chemo-embolization (TACE) assessments and 3 (6%) were patients with h/o iodinated contrast allergy. About 2 (4%) were performed on hemodynamically unstable patients in the intensive care with raised alpha fetoprotein and 2 (4%) patients were claustrophobic. The number of patients referred from clinicians steadily increased from 12 in the first 12 mo of the study to 38 in the last 12 mo. CEUS was able to diagnose 88% of positive cases of HCC as per reference standards. In the surveillance group, specificity was 53.3% vs 100% by CT/MRI. Post RFA and TACE specificity of lesion characterization by CEUS was 100% in single/large mass assessment, similar to CT/MRI. For non HCC lesions such as regenerative and dysplastic nodules, the specificity was 50% vs 90% by CT/MRI. The positive role of CEUS in imaging spectrum of HCC included a provisional urgent diagnosis of an incidentally detected mass. It further led to a decrease in time for further management. A confident diagnosis on CEUS was possible in cases of characterization of an indeterminate mass, in situations where the patient was unfit for CT/MRI, was allergic to iodinated contrast or had claustrophobia, etc. CEUS was also cost effective, radiation free and an easy modality for monitoring post RFA or TACE lesions.

CONCLUSION: CEUS is a valuable augmentation to the practice of ultrasonography, and an irreplaceable modality for confounding cases and interpretation of indeterminate lesions in imaging of HCC.

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

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

Contrast-enhanced harmonic endoscopic ultrasound is able to discriminate benign submucosal lesions from gastrointestinal stromal tumors

BACKGROUND

Although endoscopic ultrasound (EUS) has improved the diagnostic of potential malignancies, gastric lesions with suspicion of gastrointestinal stromal tumors (GIST) or benign lesions like lipoma or leiomyoma can often not be accurately differentiated by EUS, therefore, requiring tissue sampling with the risk of bleeding complications especially in GIST. As with the newest generation of EUS machines, contrast-enhanced harmonic endoscopic ultrasound (CEH-EUS) has become a new option to determine perfusion characteristics. The aim of this analysis was to evaluate whether CEH-EUS may help to discriminate various submucosal lesions.

METHODS

Data sets of 17 patients with suspicious gastric or esophageal lesions, who were investigated with CEH-EUS were analyzed. Perfusion characteristics were classified by the investigator immediately and statistically analyzed after investigation. Samples from EUS-fine needle aspirates, biopsy samples after needle cut or surgical specimen served as gold standard.

RESULTS

CEH-EUS showed nine lesions with reduced contrast enhancement (maximum intensity 6.2 ± 1.9 db) and eight lesions with hyperenhancement (47.3 ± 11.6 db). The latter eight lesions were all histologically identified as GIST, while the nine hypoenhanced lesions emerged to be four lipoma and five leiomyoma. Statistical analysis corresponded with initial perfusion classification in all cases.

CONCLUSION

This is the first study showing that CEH-EUS can discriminate GIST from benign lesions with good accuracy. In the future, CEH-EUS-guided discrimination may lead to individualized diagnostic and therapeutic strategies in handling submucosal lesions.

Contrast-enhanced ultrasonography parameters in neural network diagnosis of liver tumors

AIM: To study the role of time-intensity curve (TIC) analysis parameters in a complex system of neural networks designed to classify liver tumors.

METHODS: We prospectively included 112 patients with hepatocellular carcinoma (HCC) (n = 41), hypervascular (n = 20) and hypovascular (n = 12) liver metastases, hepatic hemangiomas (n = 16) or focal fatty changes (n = 23) who underwent contrast-enhanced ultrasonography in the Research Center of Gastroenterology and Hepatology, Craiova, Romania. We recorded full length movies of all contrast uptake phases and post-processed them offline by selecting two areas of interest (one for the tumor and one for the healthy surrounding parenchyma) and consecutive TIC analysis. The difference in maximum intensities, the time to reaching them and the aspect of the late/portal phase, as quantified by the neural network and a ratio between median intensities of the central and peripheral areas were analyzed by a feed forward back propagation multi-layer neural network which was trained to classify data into five distinct classes, corresponding to each type of liver lesion.

RESULTS: The neural network had 94.45% training accuracy (95% CI: 89.31%-97.21%) and 87.12% testing accuracy (95% CI: 86.83%-93.17%). The automatic classification process registered 93.2% sensitivity, 89.7% specificity, 94.42% positive predictive value and 87.57% negative predictive value. The artificial neural networks (ANN) incorrectly classified as hemangyomas three HCC cases and two hypervascular metastases, while in turn misclassifying four liver hemangyomas as HCC (one case) and hypervascular metastases (three cases). Comparatively, human interpretation of TICs showed 94.1% sensitivity, 90.7% specificity, 95.11% positive predictive value and 88.89% negative predictive value. The accuracy and specificity of the ANN diagnosis system was similar to that of human interpretation of the TICs (P = 0.225 and P = 0.451, respectively). Hepatocellular carcinoma cases showed contrast uptake during the arterial phase followed by wash-out in the portal and first seconds of the late phases. For the hypovascular metastases did not show significant contrast uptake during the arterial phase, which resulted in negative differences between the maximum intensities. We registered wash-out in the late phase for most of the hypervascular metastases. Liver hemangiomas had contrast uptake in the arterial phase without agent wash-out in the portal-late phases. The focal fatty changes did not show any differences from surrounding liver parenchyma, resulting in similar TIC patterns and extracted parameters.

CONCLUSION: Neural network analysis of contrast-enhanced ultrasonography - obtained TICs seems a promising field of development for future techniques, providing fast and reliable diagnostic aid for the clinician.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Contrast-enhanced gray-scale ultrasound for quantitative evaluation of tumor response to chemotherapy: preliminary results with a mouse hepatoma model

OBJECTIVE

The purpose of this study was to quantify tumor blood perfusion with contrast-enhanced gray-scale ultrasound in the evaluation of tumor response to chemotherapy.

MATERIALS AND METHODS

Mice bearing H22 hepatoma were treated with cisplatin or placebo by intraperitoneal injection. Contrast-enhanced gray-scale ultrasound was performed on day 8 after bolus injection of a lipid-based ultrasound contrast agent. Regions of interest within the tumor were analyzed offline to determine area under the curve, maximum intensity, perfusion index, mean transit time, time to peak, and quality of fit. Immediately after imaging, mice were euthanized, and tumor tissue was removed for fixation in 10% formalin solution. Microvascular density was measured after anti-CD34 staining.

RESULTS

The volume of treated tumors was significantly smaller than that of control tumors (p < 0.001). Treatment with cisplatin resulted in a significant decrease in perfusion index and maximum intensity compared with control tumors (p < 0.05). There were no significant differences between control and treated tumors (p > 0.05) with respect to area under the curve, mean transit time, and time to peak. The microvascular density of treated tumors was significantly lower than that of control tumors (p < 0.001).

CONCLUSION

Quantitative analysis of tumor blood perfusion with contrast-enhanced ultrasound can be used for noninvasive assessment of functional changes in tumors after chemotherapy.

Contrast-enhanced ultrasound for characterisation of hepatic lesions appearing non-hypervascular on CT in chronic liver diseases

OBJECTIVES

The purpose of this prospective study was to elucidate the efficacy of using contrast-enhanced ultrasound to characterise focal hepatic lesions appearing non-hypervascular on contrast-enhanced CT in chronic liver diseases.

METHODS

The study population included 22 patients with cirrhosis or chronic hepatitis, who between them had 27 focal hepatic lesions smaller than 20 mm (mean 13.9 ± 3.4) that appeared non-hypervascular on contrast-enhanced CT. Contrast-enhanced ultrasound with perflubutane microbubble agent (Sonazoid, 0.0075 ml kg(-1)) was performed prior to ultrasound-guided needle biopsy, and intensity analysis was done for hepatic lesions in the early phase (-60 s) and late phase (600 s post injection).

RESULTS

All seven early-phase hyperenhanced lesions were hepatocellular carcinoma (HCC). 20 lesions iso- or hypoenhanced during the early phase consisted of 11 regenerative nodules (RNs) and 9 HCCs. HCC was more frequent in early-phase hyperenhanced lesions than in iso- or hypoenhanced lesions (p=0.0108). Both late-phase hypoenhanced lesions were HCCs, whereas 25 late-phase isoenhanced lesions consisted of 11 RNs and 14 HCCs. The enhancement patterns of the 11 RNs included isoenhanced appearance in both the early and late phases in 8 lesions, and early-phase hypoenhancement combined with late-phase isoenhancement in the remaining 3. Both of these enhancement patterns (i.e. either iso-iso or hypo-iso) were found in 9 malignant lesions, 9 (75%) of the 12 well-differentiated HCCs.

CONCLUSION

Hypervascularity on contrast-enhanced ultrasound with Sonazoid strongly suggested HCC regardless of non-hypervascularity on CT, and late-phase hypoenhancement was another possible finding of HCC. However, characterisation of hepatic lesions with other enhancement patterns was difficult using our technique.

Assessment and management of methotrexate hepatotoxicity in psoriasis patients: report from a consensus conference to evaluate current practice and identify key questions toward optimizing methotrexate use in the clinic

Experts in psoriasis, hepatology, pharmacokinetics and pharmacogenetics convened to discuss the safety and monitoring of methotrexate with respect to hepatotoxicity when used in the treatment of psoriasis. Methotrexate is an efficacious and cost-effective treatment for psoriasis, but is associated with significant safety issues, particularly relating to hepatotoxicity. Current British, Dutch, German, EU and US guidelines for baseline evaluations, monitoring and prevention of hepatotoxicity in patients with psoriasis receiving methotrexate were evaluated. Liver safety monitoring is currently reliant upon multiple methods, including biopsy, serological tests for biomarkers such as type III procollagen amino terminal propeptide (PIIINP), and liver function tests based on liver enzymes. Monitoring of patients receiving long-term therapy is expected to be improved by the utilization of serum biomarkers currently in development such as the Enhanced Liver Fibrosis (ELF) panel and other non-invasive tests of hepatic architecture, such as fibroelastography, microbubbles and magnetic resonance imaging. Appropriate studies to determine optimal dosing to maximize efficacy and minimize toxicity, potentially utilizing pharmacogenetic principles, are clearly needed. Key questions for future research are identified including needs for optimal screening and monitoring, identification of appropriate biomarkers, assessment of relationships between dosing and safety, utility of liver biopsy, optimal dosing regimens (including route of administration), methods to measure methotrexate levels in blood, and use of methotrexate as a standardized active comparator in trials of experimental drugs used to treat psoriasis.

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

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

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

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

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

Prognostic value of portal vein involvement in patients undergoing liver transplantation for hepatocellular carcinoma

AIM: To evaluate the prognostic value of portal vein involvement in patients undergoing liver transplantation for hepatocellular carcinoma (HCC).

METHODS: One hundred and forty-eight HCC patients who underwent liver transplantation at West China Hospital of Sichuan University from January 2000 to October 2006 were included in the study. The pathological, clinical and ultrasound imaging data for these patients were analyzed retrospectively.

RESULTS: The median follow-up was 16.4 months (range: 2.8-69.5 months). During the follow-up, the overall tumor recurrence rate was 43.2%. Ultrasound examination revealed intrahepatic portal vein involvement in 32 patients, main portal vein involvement in 14 patients, and no portal vein involvement in 102 patients. Univariate COX model analysis showed that portal vein involvement was an independent predictor of actuarial survival [relative risk (RR) = 2.673, P = 0.000] and recurrence-free survival (RR = 2.951, P = 0.000). Multivariate COX proportional hazards model analysis also showed portal vein involvement was an independent predictor of actuarial survival (RR = 2.426, P = 0.000) and recurrence-free survival (RR = 2.258, P = 0.000).

CONCLUSION: Portal vein involvement is an independent prognostic factor for survival in patients undergoing liver transplantation for HCC. Ultrasound assessment of portal vein involvement can help identify indications for liver transplantation in patients with HCC.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Imaging features of hepatic angiomyolipomas on real-time contrast-enhanced ultrasound

The aim of this study was to evaluate the imaging features of hepatic angiomyolipoma (AML) on contrast-enhanced ultrasound (CEUS). The imaging features of 12 pathologically proven hepatic AML lesions in 10 patients who had undergone baseline ultrasound (BUS) and CEUS examinations were evaluated retrospectively. The enhancement extent, pattern and dynamic change, along with the enhancement process, on CEUS were analysed. The diagnostic results of BUS and CEUS before pathological examination were also recorded. The results showed that 75% (9/12) of the AML lesions exhibited mixed echogenicity on BUS and most showed remarkable hyperechogenicity in combination with a hypoechoic or anechoic portion. Arterial flow signals were detected in 75% (9/12) of the lesions on colour Doppler imaging. On CEUS, 66.7% (n = 8) of the 12 lesions exhibited hyperenhancement in the arterial phase, slight hyperenhancement (n = 2) or isoenhancement (n = 6) in the portal phase, and slight hyperenhancement (n = 1) or isoenhancement (n = 7) in the late phase. Three (25%) lesions exhibited hyperenhancement in the arterial phase and hypoenhancement in both portal and late phases. One (8.3%) lesion exhibited hypoenhancement throughout the CEUS process. Before pathological examination with BUS, only 3 (25%) lesions were correctly diagnosed as hepatic AML. Conversely, on CEUS, correct diagnoses were made for 66.8% (8/12) of hepatic AMLs. Therefore, arterial hyperenhancement and subsequent sustained enhancement on CEUS were found in the majority of hepatic AMLs. The combination of BUS and CEUS leads to the correct diagnosis in the majority of hepatic AMLs, and is higher than the success rate achieved by BUS alone.

Contrast enhanced ultrasound should be the initial radiological investigation to characterise focal liver lesions

INTRODUCTION

Contrast enhanced ultrasound (CEUS) involves the administration of a microbubble contrast agent followed by a US scan to evaluate the liver lesion through all phases of enhancement. Although technical difficulty and operator dependence can be encountered, CEUS is thought to be superior to conventional US and CT. This study aims to determine how effective CEUS is at characterising focal liver lesions and to establish its role in the diagnostic algorithm.

METHODS

All patients who underwent a liver CEUS performed by a single consultant radiologist were identified over a 5 year period. The CEUS report, CT, MRI and/or PET report, histopathology report and case notes were reviewed.

RESULTS

127 patients were included. CEUS correctly identified 71 of 77 malignant lesions and all of the benign liver lesions. The sensitivity of CEUS for detecting and correctly characterising a malignant FLL is therefore 92% with a specificity of 100%.

CONCLUSION

Our study shows that CEUS has a high sensitivity and specificity for characterising focal liver lesions. CEUS has advantages over CT and MRI of a high degree of safety, good patient tolerance and often availability at the time of initial detection. We therefore suggest that CEUS should be used as the initial study in the characterisation of FLLs. The study should be followed, as appropriate, by CT and MRI or PET studies. Biopsy, with its risks of tumour seeding and false negative results should only be considered after review of the imaging studies and full MDT discussion.

Efficacy of perflubutane microbubble-enhanced ultrasound in the characterization and detection of focal liver lesions: phase 3 multicenter clinical trial

OBJECTIVE

The purpose of this study was to assess the efficacy and safety of contrast-enhanced ultrasound performed with perflubutane microbubbles in comparison with unenhanced ultrasound and dynamic CT in the characterization of focal liver lesions during the vascular phase of imaging and in the detection of lesions during the Kupffer phase.

SUBJECTS AND METHODS

A total of 196 patients were enrolled at 15 centers in Japan. Vascular phase images were obtained before contrast injection until 1 minute after injection. Kupffer phase images were obtained 10 minutes after injection. Dual-phase CT was performed as determined by standard clinical practice at each center. Unenhanced ultrasound, contrast-enhanced ultrasound, and CT images were read by blinded reviewers, and the results they reached regarding characterization and detection were compared with reference standard findings made by onsite investigators. The safety observation period was 72 hours after contrast administration.

RESULTS

Among the 190 patients included in the characterization analysis, the accuracy of contrast-enhanced ultrasound (88.9%) was significantly greater than that of unenhanced ultrasound (68.4%) and dynamic CT (80.5%) (p < 0.001 and p = 0.008). Among the 191 patients in the detection analysis, the efficacy of contrast-enhanced ultrasound in detection of lesions was significantly higher than that of unenhanced ultrasound and dynamic CT (p < 0.001 and p = 0.008), predominantly because more metastatic lesions were detected (both p < 0.001). In particular, contrast-enhanced ultrasound was superior to dynamic CT in the detection of metastatic lesions measuring 1 cm or smaller. The incidence of adverse events was 49.2% and that of adverse drug reactions was 10.4%. All adverse drug reactions were mild.

CONCLUSION

Compared with unenhanced ultrasound and dynamic CT, contrast-enhanced ultrasound with perflubutane microbubbles improved diagnostic efficacy in both characterization and detection of focal liver lesions with no serious adverse drug reactions.

[Assessment of tumour angiogenesis using contrast-enhanced ultrasound]

Microbubbles are useful for imaging tumour angiogenesis and relatively crude forms of this approach are now routinely used for subjective diagnosis, especially in the liver. More sophisticated methods use quantitative approaches to measure the amount and the time course of bolus or reperfusion curves and have shown great promise in revealing effective tumour response to anti-angiogenic drugs in humans before tumour shrinkage occurs. These are beginning to be accepted into clinical practice. In the long term, targeted microbubbles for molecular imaging and eventually for directed anti-tumour therapy are expected to be tested.

Natural course of hepatic focal nodular hyperplasia: a long-term follow-up study with sonography

PURPOSE

We aimed to investigate the natural course of hepatic focal nodular hyperplasia (FNH) in a long-term follow-up study with sonography.

METHOD

This study comprised 30 patients (24 women and 6 men) with 34 FNHs. Diagnosis of FNH was made using color Doppler sonography, contrast-enhanced CT, or MRI in combination with needle biopsy. Patients were followed every 3 to 6 months with sonography. Regression or progression of tumor was defined as a change of over 30% in maximal diameter. Disappearance was defined as no vizualization of the tumor on at least 3 follow-up sonographic examinations.

RESULTS

Thirty-four FNHs were followed over a mean period of 42 months (range, 7-95 months). Twenty-four lesions (70.6%) were stable in size, 1 (2.9%) progressed, and 9 (26.5%) regressed. Of those that regressed, 6 (17.6%) disappeared over a mean period of 59 +/- 30 months (range, 20-95 months). Older age (OR 1.26, 95% CI 1.02-1.56; p < 0.05) and longer follow-up time (OR 1.11, 95% CI 1.01-1.21; p < 0.05) were the independent factors associated with complete regression of FNH.

CONCLUSION

Most FNHs were stable or regressed/disappeared after a long follow-up period. Based on the benign course, conservative treatment for asymptomatic FNH should be advocated.

Three-dimensional contrast-enhanced sonography of vascular patterns of focal liver tumors: pilot study of visualization methods

OBJECTIVE

We investigated visualization methods of 3D sonography with a perflubutane-based contrast agent in the imaging evaluation of vascular patterns of focal liver tumors.

MATERIALS AND METHODS

Eighty-four patients with focal liver tumors underwent automatic scanning with 3D sonography 20-60 seconds after administration of a perflubutane contrast agent. The confirmed final diagnoses were 50 hepatocellular carcinomas, 20 metastatic lesions, nine hemangiomas, and five cases of focal nodular hyperplasia. Tomographic sonographic images reconstructed in 3D parallel slices and rendered sonographic images resembling angiograms were reviewed by two readers.

RESULTS

Sonographic angiograms rendered by maximum intensity of gray values in surface smooth mode showed tumor vessels and early tumor enhancement. The average intensity of gray values with surface texture mode showed unenhanced areas within tumors. Interobserver agreement for classifying enhancement patterns with both tomographic sonography and sonographic angiography was excellent (kappa=0.84). The main pattern, intratumoral vessels with early homogeneous or heterogeneous tumor enhancement, had a sensitivity of 97% (average of both readers), specificity of 94%, and positive predictive value (PPV) of 96% for hepatocellular carcinomas. The presence of tumor vessels with early peripheral ringlike tumor enhancement had a sensitivity of 90%, specificity of 95%, and PPV of 86% for metastatic lesions. Peripheral nodular enhancement had a sensitivity of 84%, specificity of 99%, and PPV of 89% for hemangioma. The presence of spoke-wheel arteries with early tumor enhancement had a sensitivity of 80%, specificity of 100%, and PPV of 100% for focal nodular hyperplasia.

CONCLUSION

Three-dimensional sonography with a perflubutane-based contrast agent is useful in the evaluation of vascular patterns of focal liver tumors.