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

Evaluation of the clinical utility of temporal subtraction using bone suppression processing in digital chest radiography

Rationale and objectives

To evaluate the usefulness of temporal subtraction using the bone suppression method in digital chest radiography for the detection of pulmonary lesions.

Materials and methods

The images of 31 patients with pulmonary lesions and 19 normal cases were included in the study. Conventional and bone suppression temporal subtraction were performed in the 50 cases selected and used for an observer performance study. Five radiologists participated in the study, and the differences between using conventional and bone suppression temporal subtraction were assessed using jackknife free-response receiver operating characteristic analysis.

Results

The average figure-of-merit values for all radiologists increased significantly using the bone suppression method, from 0.619 (conventional) to 0.696 (p = 0.032). The average sensitivity for detecting pulmonary lesions improved from 67.9% to 75.4%, and the average number of false-positive per case decreased from 0.336 to 0.252 using bone suppression temporal subtraction.

Conclusion

Bone suppression temporal subtraction processing can assist with the detection of subtle pulmonary lesions in digital chest radiographs.

Protocol of Kupffer phase whole liver scan for metastases: A single-center prospective study

Introduction

As the presence of hepatic metastases is very important to cancer patients' clinical stage which would directly affect the selection and application of anti-cancer treatments. Although conventional ultrasound is commonly performed as a screening tool, most of the examinations have relatively poor sensitivity and specificity for detecting liver metastases. Contrast-enhanced ultrasound (CEUS) with Sonazoid has been reported to have the advantage of the diagnosis and therapeutic support of focal hepatic lesions and its specific Kupffer phase whole liver scan (KPWLS) is believed to be sensitive to detect liver metastases. And the purpose of this study is to determine the number, size, location and diagnosis of metastatic lesions, and to compare the results with conventional ultrasound and contrast-enhanced computed tomography (CECT), thus to clarify the application value, indications of Sonazoid-CEUS in screening liver metastasis.

Methods and analysis

Kupffer phase whole liver scan for metastases (KPWLSM) is a self-control, blind map-reading, single-center, prospective superiority trial. Approved by the institutional review committee, the study period is planned to be from 1 January 2022 to 31 December 2025. Our study will include 330 patients with history of malignant tumors that cling to metastasize to liver. All patients will undergo the examinations of conventional ultrasound, Sonazoid-CEUS, and contrast-enhanced magnetic resonance imaging (CEMRI), and 65 of them should have additional CECT scans. The primary endpoint is the comparative analysis of the numbers of detected liver metastatic lesions among Sonazoid-CEUS, conventional ultrasound and CECT in screening liver metastases. Subjective conditions of patient after injection of Sonazoid will be followed up 3 and 30 days after KPWLSM, and any short-term and long-term adverse events are to be recorded with telephone interviews.

Ethics and dissemination

This study has been granted by the Ethics Committee of Shanghai Jiao Tong University Affiliated Sixth People's Hospital (Approval No: 2021-197). When the KPWLSM is completed, we will publish it in an appropriate journal to promote further widespread use.

Registration

Trial Registration Number and Date of Registration: Chinese Clinical Trial Registry, ChiCTR2100054385, December 16, 2021.

Usefulness of Modified CEUS LI-RADS for the Diagnosis of Hepatocellular Carcinoma Using Sonazoid

The Contrast-Enhanced Ultrasound Liver Imaging Reporting and Data System (CEUS LI-RADS) was introduced for classifying suspected hepatocellular carcinoma (HCC). However, it cannot be applied to Sonazoid. We assessed the diagnostic usefulness of a modified CEUS LI-RADS for HCC and non-HCC malignancies based on sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Patients with chronic liver disease at risk for HCC were evaluated retrospectively. Nodules ≥1 cm with arterial phase hyperenhancement, no early washout (within 60 s), and contrast defects in the Kupffer phase were classified as LR-5. Nodules showing early washout, contrast defects in the Kupffer phase, and/or rim enhancement were classified as LR-M. A total of 104 nodules in 104 patients (median age: 70.0 years; interquartile range: 54.5-78.0 years; 74 men) were evaluated. The 48 (46.2%) LR-5 lesions included 45 HCCs, 2 high-flow hemangiomas, and 1 adrenal rest tumor. The PPV of LR-5 for HCC was 93.8% (95% confidence interval (CI): 82.8-98.7%). The 22 (21.2%) LR-M lesions included 16 non-HCC malignancies and 6 HCCs. The PPV of LR-M for non-HCC malignancies, including six intrahepatic cholangiocarcinomas, was 100% (95% CI: 69.8-100%). In conclusion, in the modified CEUS LI-RADS for Sonazoid, LR-5 and LR-M are good predictors of HCC and non-HCC malignancies, respectively.

The AFSUMB Consensus Statements and Recommendations for the Clinical Practice of Contrast-Enhanced Ultrasound using Sonazoid

The first edition of the guidelines for the use of ultrasound contrast agents was published in 2004, dealing with liver applications. The 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 nonliver applications. The third edition of the contrast-enhanced ultrasound (CEUS) guidelines was the joint World Federation for Ultrasound in Medicine and Biology-European Federation of Societies for Ultrasound in Medicine and Biology (WFUMB-EFSUMB) venture in conjunction with other regional US societies such as Asian Federation of Societies for Ultrasound in Medicine and Biology, resulting in a simultaneous duplicate on liver CEUS in the official journals of both WFUMB and EFSUMB in 2013. However, no guidelines were described mainly for Sonazoid due to limited clinical experience only in Japan and Korea. The new proposed consensus statements and recommendations provide general advice on the use of Sonazoid and are intended to create standard protocols for the use and administration of Sonazoid in hepatic and pancreatobiliary applications in Asian patients and to improve patient management.

The AFSUMB Consensus Statements and Recommendations for the Clinical Practice of Contrast-Enhanced Ultrasound using Sonazoid

The first edition of the guidelines for the use of ultrasound contrast agents was published in 2004, dealing with liver applications. The 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 nonliver applications. The third edition of the contrast-enhanced ultrasound (CEUS) guidelines was the joint World Federation for Ultrasound in Medicine and Biology-European Federation of Societies for Ultrasound in Medicine and Biology (WFUMB-EFSUMB) venture in conjunction with other regional US societies such as Asian Federation of Societies for Ultrasound in Medicine and Biology, resulting in a simultaneous duplicate on liver CEUS in the official journals of both WFUMB and EFSUMB in 2013. However, no guidelines were described mainly for Sonazoid due to limited clinical experience only in Japan and Korea. The new proposed consensus statements and recommendations provide general advice on the use of Sonazoid and are intended to create standard protocols for the use and administration of Sonazoid in hepatic and pancreatobiliary applications in Asian patients and to improve patient management.

Perfluorobutane contrast-enhanced ultrasonography: a new standard for ultrasonography-guided thermal ablation of sonographically occult liver tumours?

INTRODUCTION

Image-guided thermal ablation, preferably with ultrasonography (US), is increasingly used for treatment of small liver tumours. Perfluorobutane-contrast enhanced US (pCEUS) is a promising tool that may allow for targeting of tumours that are otherwise imperceptible on greyscale US. Although pCEUS has been reported to be effective, the literature has been limited outside of Japan and South Korea. We aimed to provide data that supports the use of pCEUS in thermal ablation of sonographically occult liver tumours.

METHODS

We conducted a retrospective single-centre study of 35 consecutive patients who underwent pCEUS-guided ablation of 48 liver tumours with a median size of 1.2 cm. Periprocedural, one-month post-treatment, and relevant follow-up imaging studies were reviewed. Electronic records were also obtained, with long-term follow-up data of 12-28 months being available for 32 patients.

RESULTS

36 (75%) of tumours that were imperceptible on greyscale US became visible with pCEUS. Overall, complete tumour ablation at one month was 89%. 1 (3%) patient developed a major complication following treatment, while 6 (17%) had minor post-treatment complaints. The local tumour progression rate was 17% with a median time of 14 months.

CONCLUSION

pCEUS has a role in US-guided thermal ablation of liver tumours, offering a high technical success rate that is comparable to reported data. Additional benefits may include improved procedural time and freedom from ionising radiation.

Value of Perfusion Parameters for Differentiating Hepatocellular Carcinoma and Liver Metastasis With Hypervascularity and a Normal Hepatic Background on Contrast-Enhanced Ultrasound Imaging

OBJECTIVES

To retrospectively evaluate the value of contrast-enhanced ultrasound (CEUS) perfusion parameters in the differential diagnosis of hepatocellular carcinomas (HCCs) and metastatic liver tumors (MLTs) with hypervascularity.

METHODS

Sixty-seven HCCs and 55 MLTs with arterial homogeneous/heterogeneous hyperenhancement on CEUS imaging and a normal liver background were included in this retrospective study. Six CEUS perfusion parameters were compared between HCCs and MLTs with different sizes and HCC differentiations: rise time (RT), time to peak (TTP), mean transit time, wash-out time (WT), maximum intensity (IMAX), and area under the curve (AUC). The area under the receiver operating characteristic curve (AUROC) was determined to compare the diagnostic efficacy of the parameters.

RESULTS

The RT, TTP, and WT were significant longer and the IMAX and AUC were significantly higher in HCCs than in MLTs. In distinguishing between HCCs and MLTs, the AUROC was highest for the WT (0.922; sensitivity, 85.1%; specificity, 89.6%); the AUC and IMAX had the second and third highest AUROCs (AUC: 0.855; sensitivity, 76.1%; specificity, 80.6%; IMAX: 0.827; sensitivity, 76.1%; specificity, 77.6%). The AUROC was lowest for the TTP and RT (TTP: 0.719; sensitivity, 70.1%; specificity, 61.2%; RT: 0.707; sensitivity, 67.2%; specificity, 65.7%). In HCCs, both the tumor size and degree of differentiation affected the IMAX, AUC, and WT. In MLTs, perfusion parameters were not influenced by the tumor size.

CONCLUSIONS

In HCCs and MLTs with hypervascularity and a normal liver background on CEUS imaging, various CEUS perfusion parameters, including IMAX, AUC, WT, RT, and TTP, differed significantly between tumor types. The WT may be the most useful parameter for differentiating between these tumors.

Visibility of focal liver lesions: Comparison between kupffer phase of CEUS with sonazoid and hepatobiliary phase of gadoxetic acid-enhanced MRI

BACKGROUND

To investigate the agreement between Kupffer phase of Sonazoid contrast-enhanced sonography (CEUS) and hepatobiliary phase of gadoxetic acid-enhanced MRI in the evaluation of focal liver lesions (FLLs).

METHODS

One hundred fifty-four FLLs in 154 patients who underwent both Sonazoid CEUS and gadoxetic acid-enhanced liver MRI were included in this retrospective study. FLL visibility on the Kupffer-phase images was graded as one (invisible or isoenhancing), two (vaguely visible or vaguely hypoenhancing), or three (clearly visible or clearly hypoenhancing), and that on the hepatobiliary-phase images of MRI was graded as one (invisible or hyper/isointense), two (vaguely visible or weakly hypointense), or three (clearly visible or strongly hypointense). Pairwise comparison of lesion visibility between the two modalities was performed, and intermodality agreement was assessed.

RESULTS

On Kupffer-phase CEUS, 31 (20.1%) lesions were invisible, 17 (11.1%) were vaguely visible, and 106 (68.9%) were clearly visible. On the hepatobiliary-phase MRI, 9 (5.9%) lesions were invisible, 45 (29.2%) were vaguely visible, and 100 (64.9%) were clearly visible. Overall, lesion visibility scores were not significantly different between the two modalities (p = 0.121), but the visibility was significantly better on MRI in smaller lesions. Twenty-eight lesions (18.2%) showed discrepancy in the visibility on CEUS and MRI, and most of the cases (89.7%) were lesions that were invisible on CEUS but visible on MRI.

CONCLUSIONS

The overall visibility of FLLs was comparable between the Kupffer phase of Sonazoid-CEUS and the hepatobiliary-phase images of gadoxetic acid-enhanced MRI, with a discrepancy between the two modalities in 18% of the cases. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:542-550, 2017.

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 features of histologically proven small (≤20 mm) liver metastases

OBJECTIVE

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Evaluation of Liver Metastases Using Contrast-Enhanced Ultrasound: Enhancement Patterns and Influencing Factors

BACKGROUND/AIMS

To evaluate the enhancement patterns of liver metastases and their influencing factors using dynamic contrast-enhanced ultrasound (CEUS).

METHODS

A total of 240 patients (139 male and 101 female; 58.5 ± 11.2 years of age) diagnosed with liver metastases in our hospital were enrolled in this study to evaluate tumor characteristics using CEUS. A comparison of enhancement patterns with tumor size and primary tumor type was performed using the chi-square test. The differences between quantitative variables were evaluated with the independent-sample t-test and one-way analysis of variance.

RESULTS

The enhancement patterns of liver metastases on CEUS were categorized as diffuse homogeneous hyperenhancement (133/240, 55.4%), rim-like hyperenhancement (80/240, 33.3%), heterogeneous hyperenhancement (10/240, 4.2%), and isoenhancement (17/240, 7.1%). There were significant differences in the enhancement patterns during the arterial phase based on the nodule size (p=0.001). A total of 231 of the nodules showed complete washout during the portal phase, and 237 nodules were hypoenhanced during the delayed phase. The washout time was correlated with tumor vascularity, with a longer washout time observed in hypervascular metastases compared to hypovascular metastases (p=0.033).

CONCLUSIONS

Diffuse homogeneous hyperenhancement followed by rapid washout was the most common enhancement pattern of liver metastases on CEUS and was affected by the nodule size and tumor vascularity. Small metastases were prone to show diffuse homogeneous hyperenhancement. Hypervascular metastases showed a significantly longer washout time compared to hypovascular metastases.

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.

Kupffer-phase findings of hepatic hemangiomas in contrast-enhanced ultrasound with sonazoid

The aim of this study was to assess quantitatively the Kupffer-phase enhancement patterns of hepatic hemangiomas in contrast-enhanced ultrasound (CEUS) with Sonazoid. A total of 46 patients with 46 hepatic hemangiomas (17.1 ± 6.2 mm in diameter, 34 typical type and 12 high-flow type) underwent CEUS in the Kupffer phase. The lesion-to-liver contrast ratio in the Kupffer phase was quantitatively assessed for both types of hemangioma. Most of the hepatic hemangiomas, whether or not they were the high-flow type, were iso- to hypo-echoic relative to the surrounding liver parenchyma. The contrast ratio was -5.33 ± 6.70 dB for the high-flow hemangiomas and -4.54 ± 6.28 dB for the typical hemangiomas. There was no significant difference in contrast ratio between the two types of lesions (p = 0.73). All of the hemangiomas, whether of typical or high-flow type, are iso- to hypo-echoic relative to the surrounding liver parenchyma on Kupffer-phase imaging.

Usefulness of contrast-enhanced intraoperative ultrasound in identifying disappearing liver metastases from colorectal carcinoma after chemotherapy

BACKGROUND

Preoperative chemotherapy sometimes makes colorectal liver metastases disappear or diminish. Contrast-enhanced intraoperative ultrasound (CE-IOUS) using perflubutane may identify such metastases.

METHODS

Among 131 consecutive patients who underwent hepatic resection, 86 had received preoperative chemotherapy. Of these patients, 72 were examined using contrast-enhanced computed tomography (CE-CT), gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI), contrast-enhanced ultrasound (CEUS), intraoperative ultrasound (IOUS), and CE-IOUS; these patients were the subject of the present study. Effects of IOUS and CE-IOUS to search for disappearing liver metastases (DLM) and tumors with a diameter of 1 cm or less based on the preoperative imaging were assessed.

RESULTS

A total of 32 DLMs were noted in 11 patients. Four DLMs were identified using IOUS, and 16 DLMs (including the four DLMs identified using IOUS) were identified using CE-IOUS. Of the 16 DLMs that were missed using both IOUS and CE-IOUS, nine were resected using anatomical resection and seven were not resected. One of the nine resected DLMs was histologically proven to be adenocarcinoma. Three of the seven unresected DLMs showed tumor regrowth during a postoperative follow-up examination. CE-IOUS identified 79 % of the 19 DLMs that were ultimately confirmed as liver metastases, whereas IOUS identified 21 % of them (p < 0.004). Among the 202 tumors that were identified using preoperative imaging, 54 were 1 cm or less in diameter. The sensitivity of CE-IOUS for these tumors were superior to CE-CT (p < 0.04) and IOUS (p < 0.04), respectively.

CONCLUSIONS

CE-IOUS might be necessary after preoperative chemotherapy for colorectal liver metastasis.

Contrast-enhanced intraoperative ultrasonography for vascular imaging of hepatocellular carcinoma: clinical and biological significance

Abnormal tumor vascularity is one of the typical features of hepatocellular carcinoma (HCC). In this study, the significance of contrast-enhanced intraoperative ultrasonography (CEIOUS) images of HCC vasculature was evaluated by clinicopathological and gene expression analyses. We enrolled 82 patients who underwent curative hepatic resection for HCC with CEIOUS. Clinicopathological and gene expression analyses were performed according to CEIOUS vasculature patterns. CEIOUS images of HCC vasculatures were classified as reticular HCC or thunderbolt HCC. Thunderbolt HCC was significantly correlated with higher alpha-fetoprotein levels, tumor size, histological differentiation, portal vein invasion, and tumor-node-metastasis stage, and these patients demonstrated a significantly poorer prognosis for both recurrence-free survival (P = 0.0193) and overall survival (P = 0.0362) compared with patients who had reticular HCC. Gene expression analysis revealed that a rereplication inhibitor geminin was significantly overexpressed in thunderbolt HCCs (P = 0.00326). In vitro knockdown of geminin gene reduced significantly the proliferation of human HCC cells. Immunohistochemical analysis confirmed overexpression of geminin protein in thunderbolt HCC (P < 0.0001). Multivariate analysis revealed geminin expression to be an independent factor in predicting poor survival in HCC patients (P = 0.0170).

CONCLUSION

CEIOUS vascular patterns were distinctly identifiable by gene expression profiling associated with cellular proliferation of HCC and were significantly related to HCC progression and poor prognosis. These findings might be clinically useful as a determinant factor in the postoperative treatment of HCC.

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.

Comparison of Kupffer-phase Sonazoid-enhanced sonography and hepatobiliary-phase gadoxetic acid-enhanced magnetic resonance imaging of hepatocellular carcinoma and correlation with histologic grading

OBJECTIVES

To determine the relative wash-out of hepatocellular carcinomas and dysplastic nodules using Kupffer-phase sonography with Sonazoid (Daiichi-Sankyo, Tokyo, Japan) enhancement and hepatobiliary-phase gadoxetic acid-enhanced magnetic resonance imaging (MRI) in the evaluation of the histopathologic grades of individual nodules.

METHODS

This retrospective study included 66 consecutive patients with 78 histologically confirmed hepatocellular carcinomas and dysplastic nodules. In patients with carcinomas, 33 were well differentiated; 29 were moderately differentiated; and 11 were poorly differentiated; and there were 5 dysplastic nodules. All patients underwent both gadoxetic acid-enhanced MRI and Sonazoid-enhanced sonography. The interval between the two imaging examinations was less than 30 days. Six radiologists independently reviewed both images and rated the degree of relative wash-out between the tumorous and nontumorous areas on Kupffer- and hepatobiliary-phase images using a continuous rating scale. We compared these results with the histopathologic grade of each nodule, and the results were then analyzed with multireader multicase receiver operating characteristic analysis.

RESULTS

The average Kupffer-phase (P < .001) and hepatobiliary-phase (P = .004) rating scores increased as the carcinomas became less differentiated (Kruskal-Wallis test). The diagnostic accuracies of the average area under the receiver operating characteristic curve, which were estimated using the confidence levels of the relative wash-out of the Kupffer- and hepatobiliary-phase images, were 0.705 and 0.785 for dysplastic nodules versus well-, moderately, and poorly differentiated carcinomas (P = .517), 0.791 and 0.687 for dysplastic nodules and well-differentiated carcinomas versus moderately and poorly differentiated carcinomas (P = .093), and 0.871 and 0.716 for dysplastic nodules and well-and moderately differentiated carcinomas versus poorly differentiated carcinomas (P = .005), respectively.

CONCLUSIONS

Kupffer-phase Sonazoid-enhanced sonography and hepatobiliary-phase gadoxetic acid-enhanced MRI may be useful in estimating the histologic grade, although Kupffer-phase Sonazoid-enhanced sonography may be more accurate in distinguishing hepatocellular carcinomas, especially moderately and poorly differentiated types.

Contrast enhanced ultrasound in the detection of liver metastases: a prospective multi-centre dose testing study using a perfluorobutane microbubble contrast agent (NC100100)

OBJECTIVE

To conduct a dose testing analysis of perfluorobutane microbubble (NC100100) contrast-enhanced ultrasound (CEUS) to determine the optimal dose for detection of liver metastases in patients with extra-hepatic primary malignancy.

METHODS

157 patients were investigated with conventional US and CEUS. CEUS was performed following intravenous administration of perfluorobutane microbubbles (using one dose of either 0.008, 0.08, 0.12 or 0.36 μL/kg body weight). Three blinded off-site readers recorded the number and locations of metastatic lesions detected by US and CEUS. Contrast enhanced CT and MRI were used as the "Standard Of Reference" (SOR). Sensitivity, specificity and accuracy of liver metastasis detection with US versus CEUS, for each dose group were obtained. Dose group analysis was performed using the Chi-square test.

RESULTS

165 metastases were present in 92 patients who each had 1-7 lesions present on the SOR. Sensitivity of US versus CEUS (for all doses combined) was 38% and 67% (p = 0.0001). The 0.12 dose group with CEUS (78%) had significantly higher sensitivity and accuracy (70%) compared to other dose groups (p < 0.05).

CONCLUSION

The diagnostic performance of CEUS is dose dependent with the 0.12 μL/kg NC100100 dose group showing the greatest sensitivity and accuracy in detection of liver metastases.

Computer-aided diagnosis for contrast-enhanced ultrasound in the liver

Computer-aided diagnosis (CAD) has become one of the major research subjects in medical imaging and diagnostic radiology. The basic concept of CAD is to provide computer output as a second opinion to assist radiologists’ image interpretations by improving the accuracy and consistency of radiologic diagnosis and also by reducing the image-reading time. To date, research on CAD in ultrasound (US)-based diagnosis has been carried out mostly for breast lesions and has been limited in the fields of gastroenterology and hepatology, with most studies being conducted using B-mode US images. Two CAD schemes with contrast-enhanced US (CEUS) that are used in classifying focal liver lesions (FLLs) as liver metastasis, hemangioma, or three histologically differentiated types of hepatocellular carcinoma (HCC) are introduced in this article: one is based on physicians’ subjective pattern classifications (subjective analysis) and the other is a computerized scheme for classification of FLLs (quantitative analysis). Classification accuracies for FLLs for each CAD scheme were 84.8% and 88.5% for metastasis, 93.3% and 93.8% for hemangioma, and 98.6% and 86.9% for all HCCs, respectively. In addition, the classification accuracies for histologic differentiation of HCCs were 65.2% and 79.2% for well-differentiated HCCs, 41.7% and 50.0% for moderately differentiated HCCs, and 80.0% and 77.8% for poorly differentiated HCCs, respectively. There are a number of issues concerning the clinical application of CAD for CEUS, however, it is likely that CAD for CEUS of the liver will make great progress in the future.

Contrast-enhanced ultrasound: The evolving applications

Contrast-enhanced ultrasound (CEUS) is a major breakthrough for ultrasound imaging in recent years. By using a microbubble contrast agent and contrast-specific imaging software, CEUS is able to depict the micro- and macro-circulation of the targeted organ, which in turn leads to improved performance in diagnosis. Due to the special dual blood supply system in the liver, CEUS is particularly suitable for liver imaging. It is evident that CEUS facilitates improvement for characterization of focal liver lesions (FLLs), detection of liver malignancy, guidance for interventional procedures, and evaluation of treatment response after local therapies. CEUS has been demonstrated to be equal to contrast-enhanced computed tomography or magnetic resonance imaging for the characterization of FLLs. In addition, the applicability of CEUS has expanded to non-liver structures such as gallbladder, bile duct, pancreas, kidney, spleen, breast, thyroid, and prostate. The usefulness of CEUS in these applications is confirmed by extensive literature production. Novel applications include detecting bleeding sites and hematomas in patients with abdominal trauma, guiding percutaneous injection therapy and therefore achieving the goal of using interventional ultrasonography in managing splenic trauma, assessing the activity of Crohn’s disease, and detecting suspected endoleaks after endovascular abdominal aneurysm repair. Contrast-enhanced intraoperative ultrasound (US) and intracavitary use of CEUS have been developed and clinically studied. The potential use of CEUS involves sentinel lymph node detection, drug or gene delivery, and molecular imaging. In conclusion, the advent of CEUS has greatly enhanced the usefulness of US and even changed the status of US in clinical practice. The application of CEUS in the clinic is continuously evolving and it is expected that its use will be expanded further in the future.