Contrast-enhanced intraoperative ultrasonography equipped with late Kupffer-phase image obtained by sonazoid in patients with colorectal liver metastases

Diagnostic Accuracy of Sonazoid-Enhanced Ultrasonography for Detection of Liver Metastasis

PURPOSE

To evaluate the potential clinical role and reliability of Sonazoid-enhanced ultrasound (SEUS) as a diagnostic tool for liver metastatic lesions.

METHODS

An extensive literature search was conducted across five electronic databases, PubMed, Scopus, Embase, Cochrane Library, and Web of Science, from their inception up to January 2024 to identify all studies evaluating the use of Sonazoid-enhanced ultrasonography for detecting hepatic metastases. A meta-analysis was performed to assess diagnostic accuracy using the Meta-DiSc 2.0 software.

RESULTS

A total of 31 studies were included, 16 of which were eligible for meta-analysis and diagnostic test accuracy evaluation. A total of 13 studies in the meta-analysis evaluated the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) for 1347 metastatic and 1565 non-metastatic liver lesions. The pooled sensitivity and specificity for CEUS were 0.88 (95% CI: 0.82-0.92) and 0.92 (95% CI: 0.84-0.96), respectively. The combined positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 11.89 (95% CI: 5.42-26.09), 0.12 (95% CI:0.08-0.19), and 91.99 (95% CI: 32.15-263.17), respectively. Additionally, four studies of the meta-analysis assessed the diagnostic performance of contrast-enhanced intraoperative sonography (CE-IOUS) in detecting 664 metastatic and 246 non-metastatic liver lesions. The pooled sensitivity and specificity for CE-IOUS were 0.93 (95% CI: 0.82-0.97) and 0.84 (95% CI: 0.65-0.93), respectively. The aggregated positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were calculated as 5.95 (95% CI: 2.32-15.25), 0.07 (95% CI: 0.02-0.24), and 77.68 (95% CI: 10.33-583.86), respectively.

CONCLUSIONS

CE-IOUS and CEUS are reliable approaches for diagnosing liver metastatic lesions. CE-IOUS, in particular, exhibits higher accuracy in identifying liver metastatic lesions, indicating its potential effectiveness in clinical practice.

Protein-Decorated Microbubbles for Ultrasound-Mediated Cell Surface Manipulation

Delivering cargo to the cell membranes of specific cell types in the body is a major challenge for a range of treatments, including immunotherapy. This study investigates employing protein-decorated microbubbles (MBs) and ultrasound (US) to "tag" cellular membranes of interest with a specific protein. Phospholipid-coated MBs were produced and functionalized with a model protein using a metallochelating complex through an NTA(Ni) and histidine residue interaction. Successful "tagging" of the cellular membrane was observed using microscopy in adherent cells and was promoted by US exposure. Further modification of the MB surface to enable selective binding to target cells was then achieved by functionalizing the MBs with a targeting protein (transferrin) that specifically binds to a receptor on the target cell membrane. Attachment and subsequent transfer of material from MBs functionalized with transferrin to the target cells significantly increased, even in the absence of US. This work demonstrates the potential of these MBs as a platform for the noninvasive delivery of proteins to the surface of specific cell types.

Contrast-Enhanced Intraoperative Ultrasonography with Kupffer Phase May Change Treatment Strategy of Metastatic Liver Tumors - A Single-Centre Prospective Study

Aim

To compare the diagnostic performance of contrast-enhanced intraoperative ultrasonography (CE-IOUS) with Kupffer phase in metastatic liver tumours.

Methods

Twenty-seven consecutive patients with liver metastasis were prospectively recruited from November 2019 to July 2020 in the Department of HPB, Beijing Hospital. MRI and Contrast Enhanced Ultrasonography (CEUS) were obtained preoperatively, and the diagnosis was made by radiologists independently and blindly. Intraoperative ultrasonography (IOUS) and CE-IOUS with Sonazoid were done by the same sophisticated surgeon and sonographer and Kupffer phase was used to detect lesions. The sensitivity and specificity to detect lesions were compared between different radiologic methods. Then, the changes in treatment strategy due to CE-IOUS with Sonazoid were analysed.

Results

Twenty-seven patients were included. In MRI, 91 lesions were detected with sensitivity 93.3% (70/75) and specificity 68.8% (11/16). In CEUS, it was 97.1% (68/70) and 86.7% (13/15) in 85 lesions. Meanwhile, in the Kupffer phase in CE-IOUS, 99 lesions were found and 8 new lesions were discovered in 7 cases, with sensitivity 97.5% (80/82) and specificity 94.1% (16/17). The four imaging methods showed no statistic significance in sensitivity and specificity in detecting lesions (Cochran’s Q 10.825, P=0.055). Treatment strategies were altered in 7 patients, 6 achieved R0 resection or ablation, and 1 patient changed from planned R0 resection to palliative surgery.

Conclusion

CE-IOUS may play a similar or even better role than other radiological methods in diagnosing liver metastasis. The CE-IOUS using Sonazoid demonstrated a high sensitivity and specificity for finding occult metastases intraoperatively and changing the treatment strategy.

Guidelines and Good Clinical Practice Recommendations for Contrast Enhanced Ultrasound (CEUS) in the Liver - Update 2020 - WFUMB in Cooperation with EFSUMB, AFSUMB, AIUM, and FLAUS

The present, updated document describes the fourth iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS), first initiated in 2004 by the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB). The previous updated editions of the guidelines reflected changes in the available contrast agents and updated the guidelines not only for hepatic but also for non-hepatic applications.The 2012 guideline requires updating as previously the differences of the contrast agents were not precisely described and the differences in contrast phases as well as handling were not clearly indicated. In addition, more evidence has been published for all contrast agents. The update also reflects the most recent developments in contrast agents, including the United States Food and Drug Administration (FDA) approval as well as the extensive Asian experience, to produce a truly international perspective.These guidelines and recommendations provide general advice on the use of ultrasound contrast agents (UCA) and are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis to improve the management of patients.

Guidelines and Good Clinical Practice Recommendations for Contrast-Enhanced Ultrasound (CEUS) in the Liver-Update 2020 WFUMB in Cooperation with EFSUMB, AFSUMB, AIUM, and FLAUS

The present, updated document describes the fourth iteration of recommendations for the hepatic use of contrast-enhanced ultrasound, first initiated in 2004 by the European Federation of Societies for Ultrasound in Medicine and Biology. The previous updated editions of the guidelines reflected changes in the available contrast agents and updated the guidelines not only for hepatic but also for non-hepatic applications. The 2012 guideline requires updating as, previously, the differences in the contrast agents were not precisely described and the differences in contrast phases as well as handling were not clearly indicated. In addition, more evidence has been published for all contrast agents. The update also reflects the most recent developments in contrast agents, including U.S. Food and Drug Administration approval and the extensive Asian experience, to produce a truly international perspective. These guidelines and recommendations provide general advice on the use of ultrasound contrast agents (UCAs) and are intended to create standard protocols for the use and administration of UCAs in liver applications on an international basis to improve the management of patients.

Contrast-Enhanced Ultrasound of Focal Liver Masses: A Success Story

The epidemic of increasing fatty liver disease and liver cancer worldwide, and especially in Western society, has given new importance to non-invasive liver imaging. Contrast-enhanced ultrasound (CEUS) using microbubble contrast agents provides unique advantages over computed tomography (CT) and magnetic resonance imaging (MRI), the currently established methods. CEUS provides determination of malignancy and allows excellent differential diagnosis of a focal liver mass, based on arterial phase enhancement patterns and assessment of the timing and intensity of washout. Today, increased use of CEUS has provided safe and rapid diagnosis of incidentally detected liver masses, improved multidisciplinary management of nodules in a cirrhotic liver, facilitated ablative therapy for liver tumors and allowed diagnosis of hepatocellular carcinoma without biopsy. Benefits of CEUS include the dynamic real-time depiction of tumor perfusion and the fact that it is a purely intravascular agent, accurately reflecting tumoral and inflammatory blood flow. CEUS has many similarities to contrast-enhanced CT and MRI but also unique differences, which are described. The integration of CEUS into a multimodality imaging setting optimizes patient care.

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.

Imaging Methods for Ultrasound Contrast Agents

Microbubble contrast agents were introduced more than 25 years ago with the objective of enhancing blood echoes and enabling diagnostic ultrasound to image the microcirculation. Cardiology and oncology waited anxiously for the fulfillment of that objective with one clinical application each: myocardial perfusion, tumor perfusion and angiogenesis imaging. What was necessary though at first was the scientific understanding of microbubble behavior in vivo and the development of imaging technology to deliver the original objective. And indeed, for more than 25 years bubble science and imaging technology have evolved methodically to deliver contrast-enhanced ultrasound. Realization of the basic bubbles properties, non-linear response and ultrasound-induced destruction, has led to a plethora of methods; algorithms and techniques for contrast-enhanced ultrasound (CEUS) and imaging modes such as harmonic imaging, harmonic power Doppler, pulse inversion, amplitude modulation, maximum intensity projection and many others were invented, developed and validated. Today, CEUS is used everywhere in the world with clinical indications both in cardiology and in radiology, and it continues to mature and evolve and has become a basic clinical tool that transforms diagnostic ultrasound into a functional imaging modality. In this review article, we present and explain in detail bubble imaging methods and associated artifacts, perfusion quantification approaches, and implementation considerations and regulatory aspects.

Flash Imaging Used in the Post-vascular Phase of Contrast-Enhanced Ultrasonography is Useful for Assessing the Progression in Patients with Hepatitis C Virus-Related Liver Disease

Sonazoid is a commonly used contrast agent for characterizing liver tumors in ultrasonography (US). We performed flash imaging in the post-vascular phase of contrast-enhanced US (CEUS) to investigate associations between collapse of Sonazoid microbubbles (MB) and progression of liver disease. This study enrolled 409 patients (205 men, 204 women) with hepatitis C virus-related liver disease (CLD) between 2007 and 2017 (mean age 60 ± 14 y; range 20-90 y). In the post-vascular phase, 10 min after administering Sonazoid, flash imaging was performed to burst MB in the liver parenchyma; the range of bubble destruction was measured from the surface of the liver. The range of bubble destruction, stage of fibrosis, shear wave velocity (Vs), serologic markers and fibrosis-4 (FIB4) index were analyzed in 259 patients who underwent liver biopsy. Fibrosis stage was F0-1 in 108 patients, F2 in 73, F3 in 38 and F4 in 40. In 150 patients with cirrhosis, diagnosis was made based on imaging findings. The range of bubble destruction was 42.0 ± 10.4 mm in F0-1 patients, 42.9 ± 13.2 mm in F2, 51.5 ± 15.9 mm in F3 and 55.4 ± 17.3 mm in F4 and was significantly increased according to progression of fibrosis staging. The range of bubble destruction was positively correlated with Vs (r = 0.34; p < 0.01), total bilirubin (r = 0.25; p < 0.01) and FIB4 index (r = 0.38; p < 0.01). In contrast, the range of bubble destruction was negatively correlated with serum levels of albumin (r = -0.34; p < 0.01), platelet count (r = -0.35; p < 0.01) and prothrombin time (r = -0.36; p < 0.01). The results indicated that flash imaging in the post-vascular phase of CEUS was a non-invasive assessment and could predict disease progression in patients with CLD.

A radiologist's point of view in the presurgical and intraoperative setting of colorectal liver metastases

Multidisciplinary management of patients with metastatic colorectal cancer requires in each phase an adequate choice of the most appropriate imaging modality. The first challenging step is liver lesions detection and characterization, using several imaging modality ultrasound, computed tomography, magnetic resonance and positron emission tomography. The criteria to establish the metastases resectability have been modified. Not only the lesions number and site but also the functional volume remnant after surgery and the quality of the nontumoral liver must be taken into account. Radiologists should identify the liver functional volume remnant and during liver surgical procedures should collaborate with the surgeon to identify all lesions, including those that disappeared after the therapy, using intraoperative ultrasound with or without contrast medium.

Contrast-enhanced ultrasound of malignant liver lesions

Contrast-enhanced ultrasound (CEUS) is a safe, relatively inexpensive, and widely available imaging technique using dedicated imaging ultrasound sequences and FDA-approved contrast microbubbles that allow detection and characterization of malignant focal liver lesions with high diagnostic accuracy. CEUS provides dynamic real-time imaging with high spatial and temporal capability, allowing for unique contributions to the already established protocols for diagnosing focal liver lesions using CT and MR imaging. In patients with lesions indeterminate on CT and MRI, CEUS is a helpful problem-solving complementary tool that improves patient management. Furthermore, CEUS assists guidance of liver biopsies and local treatment. Variations of CEUS such as DCE-US and ultrasound molecular imaging are emerging for quantitative monitoring of treatment effects and possible earlier detection of cancer. In this review, basic principles of CEUS techniques and ultrasound contrast agents along with a description of the enhancement patterns of malignant liver lesions are summarized. Also, a discussion of the role of CEUS for treatment guidance and monitoring, intraoperative CEUS, and an outlook on emerging applications is provided.

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.

Intraoperative ultrasound for the colorectal surgeon: current trends and barriers

Up to two thirds of patients diagnosed with colorectal cancer (CRC) develop colorectal liver metastases (CRLMs) and one quarter of patients present with synchronous metastases. Early detection of CRLM widens the scope of potential treatment. Surgery for CRLM offers the best chance of a cure. Current preoperative staging of CRC relies on computerized tomography and magnetic resonance imaging. Intraoperative ultrasound (IOUS) scans and contrast-enhanced IOUS (CE-IOUS) have been demonstrated to detect additional metastases not seen on routine preoperative imaging. IOUS is not widely used by colorectal surgeons during primary resection for CRC. Confident use of IOUS/CE-IOUS during primary resection of CRC may improve decision-making by providing the most sensitive form of liver staging even when compared with magnetic resonance imaging. This may be particularly important in the era of laparoscopic resections, where the colorectal surgeon loses the opportunity to palpate the liver. There are several implied barriers to the routine use of IOUS/CE-IOUS by colorectal surgeons. These include time pressure, familiarity with techniques, a perceived learning curve, cost implications and limitation of the modality due to operator variations. Inclusion of IOUS in the training of colorectal surgeons and further investigation of potential benefits of IOUS/CE-IOUS could potentially reduce these barriers, enabling usage during primary resection for CRC to become more widespread.

Routine Preoperative Liver-specific Magnetic Resonance Imaging Does Not Exclude the Necessity of Contrast-enhanced Intraoperative Ultrasound in Hepatic Resection for Colorectal Liver Metastasis

OBJECTIVES

To assess the usefulness of contrast-enhanced intraoperative ultrasound (CE-IOUS) during surgery for colorectal liver metastases (CRLM) when gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI) is performed as a part of preoperative imaging work-up.

BACKGROUND

EOB-MRI is expected to supersede CE-IOUS, which is reportedly indispensable in surgery for CRLM.

METHODS

One hundred consecutive patients underwent EOB-MRI, contrast-enhanced computed tomography (CE-CT), and contrast-enhanced ultrasound within 1 month before surgery for CRLM. Conventional IOUS and subsequent CE-IOUS using perflubutane were performed after the laparotomy. All the nodules identified in any of the preoperative or intraoperative examinations were resected and were submitted for histological examination, in principle.

RESULTS

Preoperative imaging examinations identified 242 nodules; 25 additional nodules were newly identified using IOUS, 22 additional nodules were newly identified during CE-IOUS, and a histological examination further identified 4 nodules. Among the 25 nodules newly identified using IOUS, all 21 histologically proven CRLMs and 3 of the 4 benign nodules were correctly diagnosed using CE-IOUS. Among the 22 nodules newly identified using CE-IOUS, 17 nodules in 16 patients were histologically diagnosed as CRLMs. The planned surgical procedure was modified on the basis of IOUS and CE-IOUS findings in 12 and 14 patients, respectively. The sensitivity, positive-predictive value, and accuracy of CE-IOUS were 99%, 98%, and 97%, respectively. Those values of EOB-MRI (82%, 99%, 83%, respectively) were similar to CE-CT (81%, 99%, 81%, respectively).

CONCLUSIONS

CE-IOUS is useful in hepatic resection for CRLM, even if EOB-MRI and CE-CT are performed.

Is Strain Elastography (IO-SE) Sufficient for Characterization of Liver Lesions before Surgical Resection--Or Is Contrast Enhanced Ultrasound (CEUS) Necessary?

Aim

To evaluate the diagnostic accuracy of IO-SE in comparison to IO-CEUS for the differentiation between malignant and benign liver lesions.

Material and Methods

In a retrospective diagnostic study IO-CEUS and SE examinations of 49 liver lesions were evaluated and compared to histopathological examinations. Ultrasound was performed using a multifrequency linear probe (6–9 MHz). The loops of CEUS were evaluated up to 5 min. The qualitative characterization of IO-SE was based on a color coding system (blue = hard, red = soft). Stiffness of all lesions was quantified by a specific scaling of 0–6 (0 = low, 6 = high) using 7 ROIs (2 central, 5 peripheral).

Results

All malignant lesions displayed a characteristic portal venous washout and could be diagnosed correctly by IO-CEUS. 3/5 benign lesions could not be characterized properly either by IO-CEUS or IO-SE prior to resection. Thus for IO-CEUS sensitivity, specificity, positive and negative predictive value and accuracy were 100%, 40%, 94%, 100% and 94%. Lesion sizes were between 8 and 59 mm in diameter. Regarding the IO-SE, malignant lesions showed a marked variability. In qualitative analysis, 31 of the malignant lesions were blue colored denoting overall induration. Thirteen malignant lesions showed an inhomogenous color pattern with partial indurations. Two of the benign lesions also displayed overall induration. The other benign lesions showed an inhomogenous color mapping. Calculated sensitivity of the SE was 70.5%, specificity 60%, PPV 94%, NPV 18.75%, and accuracy 69%.

Conclusion

IO-CEUS is useful for localization and characterization of liver lesions prior to surgical resection whereas IO-SE provided correct characterization only for a limited number of lesions.

The role of intraoperative ultrasonography in the diagnosis and management of focal hepatic lesions

Intraoperative ultrasonography (IOUS) has been widely utilized in hepatic surgery both as a diagnostic technique and in the course of treatment. Since IOUS involves direct-contact imaging of the target organ, it can provide high spatial resolution without interference from the surrounding structures. Therefore, IOUS may improve the detection, characterization, localization, and local staging of hepatic tumors. IOUS is also a real-time imaging modality capable of providing interactive information and valuable guidance in a range of procedures. Recently, contrast-enhanced IOUS, IOUS elastography, and IOUS-guided hepatic surgery have attracted increasing interest and are expected to lead to the broader implementation of IOUS. Herein, we review the various applications of IOUS in the diagnosis and management of focal hepatic lesions.

Usefulness of contrast-enhanced ultrasound with Sonazoid for evaluating liver abscess in comparison with conventional B-mode ultrasound

AIM

The purpose of this study was to evaluate the usefulness of contrast-enhanced ultrasound (CEUS) with Sonazoid (perfluorobutane) in patients with liver abscess. Sonazoid is a contrast agent with a low mechanical index and is phagocytosed by Kupffer cells.

METHODS

Twenty-two patients with liver abscess were evaluated with conventional US, real-time CEUS with Sonazoid, and enhanced computed tomography (CT). After 0.5 mL of Sonazoid was administrated i.v., CEUS images in the vascular and post-vascular phases were observed.

RESULTS

Conventional US showed hypoechoic lesions in 13 (59.1%), isoechoic in four (18.2%), hyperechoic in two (9.1%), mixed echoic in two (9.1%) and undetected in one (4.8%) patient. CEUS showed perilesional enhancement in 19 (86.4%) lesions in the vascular phase and well-defined unenhanced areas in 22 (100%) lesions in the post-vascular phase. CEUS revealed that 18 abscesses were cystic type and three were honeycomb type. Twenty-one abscesses (95.5%) had clearer appearances on CEUS than on conventional US in regard to the extent of necrotic or liquefied lesions seen. We could confirm reduction of the lesions after therapy in 13 (92.9%) of 14 patients followed up by CEUS.

CONCLUSION

Most of the liver abscesses showed perilesional enhancement in the vascular phase and unenhanced areas in the post-vascular phase. The appearance of liver abscesses was clearer on CEUS than on conventional US. CEUS with Sonazoid can be a more effective diagnostic and therapeutic tool for liver abscess.

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.

Targeted ultrasound microbubble contrast agents for enhanced tumor imaging

In the field of medical ultrasound, ultrasound microbubbles are a new class of ultrasound contrast agents. Ultrasound microbubbles can be divided into two types: ordinary and targeted microbubbles. Ordinary microbubbles have been widely used in clinical practice. Targeted microbubbles are a special class of contrast agents and can be divided into micron- and nano-scale targeted microbubbles according to particle size. The former cannot pass through the endothelial gap due to the larger particle size, while the latter can pass through the vascular endothelium and allows for imaging of the extravascular tissues. Ultrasound combined with targeted microbubbles in enhancing tumor imaging shows greater advantages and has become an important topic of research; however, its unknown toxicity limits its wider application. In addition, ultrasound parameters still need to be optimized.

Usefulness of intraoperative diagnosis of hepatic tumors located at the liver surface and hepatic segmental visualization using indocyanine green-photodynamic eye imaging

BACKGROUND

To improve the diagnostic accuracy for hepatic tumors on the liver surface, we investigated the usefulness of an indocyanine green-photodynamic eye (ICG-PDE) system by comparison with Sonazoid intraoperative ultrasonography (IOUS) in 117 patients. Hepatic segmentation by ICG-PDE was also evaluated.

METHODS

ICG was administered preoperatively for functional testing and images of the tumor were observed during hepatectomy using a PDE camera. ICG was injected into portal veins to determine hepatic segmentation.

RESULTS

Accurate diagnosis of liver tumors was achieved with ICG-PDE in 75% of patients, lower than with IOUS (94%). False-positive and false-negative diagnosis rates for ICG-PDE were 24% and 9%, respectively. New small HCCs were detected in 3 patients. The ICG fluorescent pattern in tumors was strong staining in 41%, weak staining in 13%, rim staining in 20% and no staining in 26%. Hepatocellular carcinoma predominantly showed strong staining (61%), while rim staining predominated in cholangiocellular carcinoma (60%) and liver metastasis (55%). Hepatic segmental staining was performed in 28 patients, proving successful in 89%.

CONCLUSION

ICG-PDE is a useful tool for detecting the precise tumor location at the liver surface, identifying new small tumors, and determining liver segmentation for liver resection.

Potential value of sonazoid-enhanced intraoperative laparoscopic ultrasonography for liver assessment during laparoscopy-assisted colectomy

Purpose

Laparoscopy-assisted colectomy (LAC) has gained acceptance for the treatment of colorectal cancer. However, conventional palpation of the liver and adequate observation of the abdominal cavity are not achievable during LAC. The aim of this study was to assess the clinical value of using Sonazoid (contrast enhanced)-intraoperative laparoscopic ultrasonography (S-IOLUS) in patients with primary colorectal cancer.

Methods

From May 2005 to August 2008, 454 patients underwent 339 LACs and 115 open colectomies for colorectal cancer. One hundred forty-eight patients with clinical stage II or III colorectal cancer, as determined by preoperative imaging, who were undergoing LACs were prospectively enrolled.

Results

Although IOLUS did not detect any lesions, small hypoechoic lesions were detected by the S-IOLUS (n = 71) in the Kupffer-phase view of two patients (2.8 %). None of the 71 patients who underwent S-IOLUS showed liver metastases within 6 months after LAC. In the conventional IOLUS group (n = 77), metastatic lesions were identified in two patients (2.6 %). The new liver metastases in these two patients were detected within 6 months after LAC.

Conclusions

S-IOLUS of the liver during colorectal cancer surgery is useful for staging and as a diagnostic modality. It can identify lesions that are undetectable by preoperative imaging, and may be considered for routine use during LAC.

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.

Contrast-enhanced intraoperative ultrasound for hepatocellular carcinoma: high sensitivity of diagnosis and therapeutic impact

BACKGROUND

Postoperative early recurrence is a crucial issue in the treatment of hepatocellular carcinoma (HCC) patients. Some early recurrences seem to occur from minute tumors which were overlooked during both preoperative and intraoperative investigations. Therefore, it is urgently necessary to increase detectability of minute HCCs during operation. If they could be detected and resected during surgery, the prognosis should be improved. The purpose of this study is to investigate the usefulness of contrast-enhanced intraoperative ultrasound (CEIOUS) for the diagnosis and treatment of HCC.

METHODS

Institutional ethics committee approval and informed consent were obtained. Fifty-two patients (mean age 65 years; 38 males and 14 females) who underwent liver resection with either preoperative computed tomography during angiography (CTA) or CEIOUS with Sonazoid (perflubutane microbubble contrast agent) were studied. We determined the presence of HCC on the basis of the histopathological findings of resected specimens.

RESULTS

The sensitivity of CEIOUS [97.6% (95% CI 91.8-99.4)] was higher than that of CTA [89.4% (95% CI 81.1-94.3)]. The positive predictive values of CEIOUS [91.2% (95% CI 83.6-95.5) and CTA [91.6% (95% CI 83.6-95.9)] were similar. Eight new HCCs from 7 patients, which accounted for 9.4% (8/85) of the total HCCs, were correctly detected and diagnosed by CEIOUS, and we performed an additional partial hepatectomy in 3 of these 7 patients.

CONCLUSIONS

CEIOUS with Sonazoid provided increased sensitivity of detection of small HCCs compared with preoperative CTA, thereby leading to a more appropriate surgical procedure and contributing to complete tumor removal.

20 years of ultrasound contrast agent modeling

The merits of ultrasound contrast agents (UCAs) were already known in the 1960s. It was, however, not until the 1990s that UCAs were clinically approved and marketed. In these years, it was realized that the UCAs are not just efficient ultrasound scatterers, but that their main constituent, the coated gas microbubble, acts as a nonlinear resonator and, as such, is capable of generating harmonic energy. Subharmonic, ultraharmonic, and higher harmonic frequencies of the transmitted ultrasound frequency have been reported. This opened up new prospects for their use and several detection strategies have been developed to exploit this harmonic energy to discriminate the contrast bubbles from surrounding tissue. This insight created a need for tools to study coated bubble behavior in an ultrasound field and the first models were developed. Since then, 20 years have elapsed, in which a broad range of UCAs and UCA models have been developed. Although the models have helped in understanding the responses of coated bubbles, the influence of the coating has not been fully elucidated to date and UCA models are still being improved. The aim of this review paper is to offer an overview in these developments and indicate future directions for research.

Fate of metastatic foci after chemotherapy and usefulness of contrast-enhanced intraoperative ultrasonography to detect minute hepatic lesions

BACKGROUND/PURPOSE

Along with advances in the chemotherapy for colorectal cancer, the strategy for hepatic metastasis has been changed. One of the most striking issues is that initially unresectable hepatic metastases can be resectable after chemotherapy with considerably high frequency. In addition, advanced chemotherapy leads to the downsizing of the metastatic foci in the liver, which is sometimes difficult to detect with conventional intraoperative ultrasonography (IOUS). To discover the undetectable hepatic lesions with IOUS, we have introduced contrast-enhanced intraoperative ultrasonography (CEIOUS). In the present study, we present evidence that viable cancer cells exist in even the shrunken tumors with high frequency and that CEIOUS contributes to detecting the minute foci.

METHODS

This study was composed of eight patients; four of them had initially unresectable metastasis, and the remaining four had either H2 or H3 status of hepatic metastases. All of them underwent hepatic resection after chemotherapy.

RESULTS

A total of 57 metastatic lesions were detected before chemotherapy. Thirty lesions were demonstrated by CEIOUS with perflubutane and resected. In the pathological examination, tumor cells were not found in 12 of the 30 resected lesions. The degree of pathological liver damage was grade 1 or less in all patients, and no serious complication occurred after surgery in any of the patients.

CONCLUSION

The present study showed that viable cancer cells remained with high frequency, even in the minute hepatic metastasis which was reduced in size after chemotherapy, and CEIOUS was a useful examination for detecting the minute hepatic foci.

Contrast-enhanced intraoperative ultrasonography using perfluorobutane microbubbles for the enumeration of colorectal liver metastases

BACKGROUND

Intraoperative ultrasonography (IOUS) is considered the standard for the identification of liver metastases. Use of lipid-stabilized perfluorobutane microbubbles as an ultrasound contrast agent may improve this. The value of contrast-enhanced IOUS (CE-IOUS) in enumerating colorectal liver metastases was studied here.

METHODS

CE-IOUS was performed in consecutive resections for colorectal liver metastases in 2007-2010. All patients underwent preoperative computed tomography. Magnetic resonance imaging was not carried out routinely. Conventional intraoperative examination including IOUS, and CE-IOUS with peripherally injected contrast were performed. The histopathological findings and 6-month follow-up images were used as the reference standard.

RESULTS

The study group of 102 patients had a total of 315 lesions identified on preoperative imaging (2·4 lesions per operation; 129 operations). Conventional intraoperative examination including IOUS identified 350 lesions (2·7 per operation). CE-IOUS identified 370 lesions (2·9 per operation). The sensitivity, specificity and accuracy of CE-IOUS were 97·1, 59·1 and 93·2 per cent respectively. The CE-IOUS findings altered the surgical plan in 19 operations (14·7 per cent).

CONCLUSION

CE-IOUS provided additional information to that obtained using contemporary preoperative imaging and conventional intraoperative examinations.

Usefulness of contrast-enhanced intraoperative ultrasound using Sonazoid in patients with hepatocellular carcinoma

OBJECTIVE

To assess the usefulness of contrast-enhanced intraoperative ultrasound (CE-IOUS) using Sonazoid (gaseous perflubutane) in patients with hepatocellular carcinoma (HCC).

BACKGROUND

Contrast-enhanced intraoperative ultrasound using Sonazoid, a novel ultrasonic contrast agent enabling Kupffer imaging, may enable differentiation of HCC among new focal liver lesions found during fundamental intraoperative ultrasound (fundamental-NFLLs).

METHODS

Between February 2007 and February 2009, a total of 192 consecutive patients were enrolled. Fundamental intraoperative ultrasound and CE-IOUS were performed successively after laparotomy. The vascularity of 1 representative lesion was examined in harmonic mode for approximately 1 minute after the intravenous injection of Sonazoid (vascular phase). Approximately 15 minutes after the vascular phase, total liver scanning in the harmonic mode was commenced (Kupffer phase). One additional injection of Sonazoid was allowed to examine the vascularity of another lesion, if necessary. A tentative diagnosis of HCC was made when a lesion was either hypervascular during the vascular phase or hypoechoic during the Kupffer phase. A final diagnosis of HCC was made on the basis of the results of a histological examination or dynamic computed tomography findings obtained during the 12-month postoperative period.

RESULTS

Seventy-nine fundamental-NFLLs were found in 50 patients (26%), 17 (22%) of which were finally diagnosed as HCC. The sensitivity, specificity, and accuracy of CE-IOUS for differentiating HCC among fundamental-NFLLs were 65%, 94%, and 87%, respectively. Contrast-enhanced intraoperative ultrasound identified 21 additional new hypoechoic lesions in 16 patients, of which 14 lesions (67%) in 11 patients were finally diagnosed as HCC. This prospective study protocol was approved by the institutional review board of the Tokyo University Hospital. An English-language summary of the protocol was submitted (registration ID: UMIN000003046) to the Clinical Trials Registry managed by the University Hospital Medical Information Network in Japan (http://www.umin.ac.jp/ctr/index.htm).

CONCLUSIONS

With help of CE-IOUS using Sonazoid, more accurate intraoperative staging for HCC can be performed.

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.

[Hepatectomy for colorectal liver metastases after neoadjuvant chemotherapy]

The majority of patients with colorectal liver metastases receive systemic chemotherapy. In the context of unresectable liver metastases, the objective of chemotherapy based on new and more effective regimens is not only to prolong survival, but also to induce enough response and shrinkage of the tumor to render resectable patients initially not deemed to be surgical candidates. In patients with resectable liver metastases, the goal of chemotherapy is to improve the outcome after surgery and especially to decrease the risk of recurrence. Although the principles of combined modality treatment become widely accepted, this therapeutic strategy is also associated with potential risks related to the preoperative use of chemotherapy.

Targeted renal therapies through microbubbles and ultrasound

Microbubbles and ultrasound enhance the cellular uptake of drugs (including gene constructs) into the kidney. Microbubble induced modifications to the size selectivity of the filtration capacity of the kidney may enable drugs to enter previously inaccessible compartments of the kidney. So far, negative renal side-effects such as capillary bleeding have been reported only in rats, with no apparent damage in larger models such as pigs and rabbits. Although local delivery is accomplished by applying ultrasound only to the target area, efficient delivery using conventional microbubbles has depended on the combined injection of both drugs and microbubbles directly into the renal artery. Conjugation of antibodies to the shell of microbubbles allows for the specific accumulation of microbubbles in the target tissue after intravenous injection. This exciting approach opens new possibilities for both drug delivery and diagnostic ultrasound imaging in the kidney.

Contrast-enhanced sonography-guided radiofrequency ablation for the local recurrence of previously treated hepatocellular carcinoma undetected by B-mode sonography

BACKGROUND.: The purpose of this study was to assess the usefulness of contrast-enhanced sonography (CEUS) with Sonazoid to demonstrate local recurrence of hepatocellular carcinoma previously treated with radiofrequency ablation (RFA) and not seen on conventional sonography, prior to repeat RFA. METHODS.: This study included 16 cirrhotic patients with 17 cases of hypervascular locally recurrent hepatocellular carcinoma found by contrast-enhanced multidetector row CT (MDCT) but not seen on noncontrast sonography. We used Kupffer-phase imaging and vascular-phase imaging after re-injection. The morphologic patterns of local recurrence detected on CEUS were compared with those on MDCT. We performed repeat RFA guided by CEUS using Kupffer-phase imaging after re-injection. RESULTS.: We were able to detect on CEUS the location of all local recurrences with positive enhancement after re-injection. The morphologic patterns of local recurrence on CEUS were in concordance with those found on MDCT in all lesions. Repeat percutaneous RFA was successfully performed in all lesions. CONCLUSIONS.: The CEUS appearance of local recurrences correlated well with those on MDCT. A wider use of CEUS to guide repeat of percutaneous RFA may be possible with Sonazoid.

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.

Evaluation of local recurrence after treatment for hepatocellular carcinoma by contrast-enhanced ultrasonography using Sonazoid: comparison with dynamic computed tomography

PURPOSE

To evaluate the effectiveness of contrast-enhanced ultrasonography (CEUS) using Sonazoid for the diagnosis of the local recurrence after treatment for hepatocellular carcinoma (HCC) by comparing it with dynamic CT.

METHODS

Seventy-one patients with 87 HCC lesions (mean +/- SD; 19.5 +/- 9.6 mm) underwent CEUS using Sonazoid and dynamic CT after radiofrequency ablation (n = 55), transcatheter arterial chemoembolization (n = 22), or radiofrequency ablation combined with transcatheter arterial chemoembolization (n = 10). Two hepatologists (observer 1; 10 years of experience, and 2; 20 years of experience) reviewed the CEUS and dynamic CT images independently and evaluated presence or absence of the local recurrence. Diagnostic performance for the local recurrence was assessed using receiver operating characteristic curve analysis.

RESULTS

The Az value for dynamic CT was significantly lower in observer 1 than 2 (p < 0.05). The sensitivity of CEUS was 79% in observer 1 and 83.9% in observer 2, and that of dynamic CT was 83.9% and 90.3%, respectively. The specificity of CEUS was 96%, and that of dynamic CT was 92%, in both observers.

CONCLUSION

This study suggests that CEUS using Sonazoid is less affected by the observer's experience and is more accurate in the diagnosis of local recurrence after treatment for HCC than dynamic CT.

Contrast-enhanced intraoperative ultrasound improves detection of liver metastases during surgery for primary colorectal cancer

BACKGROUND

Computed tomography (CT) is the most common staging investigation in colorectal cancer (CRC). Up to 25% of patients are found to have previously undetected hepatic lesions when intraoperative ultrasound (IOUS) of the liver is used during CRC resection. We aimed to assess the ability of IOUS to detect additional liver lesions/metastases at primary colorectal resection, and to evaluate whether contrast-enhanced IOUS (CE-IOUS) improves the detection and characterization of hepatic lesions.

METHODS

We performed a single-centre, prospective pilot study. At CRC resection, patients underwent IOUS of the liver. Contrast-enhanced IOUS of the liver was undertaken using i.v. sulphur hexafluoride micro-bubbles (SonoVue, 4.8 ml). Findings of CT, non-enhanced IOUS and CE-IOUS were compared. Changes in staging or management were noted. Additional lesions were corroborated with iron oxide magnetic resonance imaging (MRI).

RESULTS

Among 21 patients, IOUS demonstrated additional lesions in seven (33%). Contrast altered the diagnosis of non-enhanced IOUS in four (20%) and changed the management strategy in three (14%) patients. Thus, IOUS in combination with the contrast agent altered the intraoperative or postoperative management plan in four patients.

CONCLUSIONS

In the first study of its kind, early results suggest that the ability of IOUS to detect additional metastases is improved by CE-IOUS, and that this may impact on surgical staging and management.

Contrast enhanced ultrasound of hepatocellular carcinoma

Sonazoid (Daiichi Sankyo, Tokyo, Japan), a second-generation of a lipid-stabilized suspension of a perfluorobutane gas microbubble contrast agent, has been used clinically in patients with liver tumors and for harmonic gray-scale ultrasonography (US) in Japan since January 2007. Sonazoid-enhanced US has two phases of contrast enhancement: vascular and late. In the late phase of Sonazoid-enhanced US, we scanned the whole liver using this modality at a low mechanical index (MI) without destroying the microbubbles, and this method allows detection of small viable hepatocellular carcinoma (HCC) lesions which cannot be detected by conventional US as perfusion defects in the late phase. Re-injection of Sonazoid into an HCC lesion which previously showed a perfusion defect in the late phase is useful for confirming blood flow into the defects. High MI intermittent imaging at 2 frames per second in the late phase is also helpful in differentiation between necrosis and viable hypervascular HCC lesions. Sonazoid-enhanced US by the coded harmonic angio mode at a high MI not only allows clear observation of tumor vessels and tumor enhancement, but also permits automatic scanning with Sonazoid-enhanced three dimensional (3D) US. Fusion images combining US with contrast-enhanced CT or contrast-enhanced MRI have made it easy to detect typical or atypical HCC lesions. By these methods, Sonazoid-enhanced US can characterize liver tumors, grade HCC lesions histologically, recognize HCC dedifferentiation, evaluate the efficacy of ablation therapy or transcatheter arterial embolization, and guide ablation therapy for unresectable HCC. This article reviews the current developments and applications of Sonazoid-enhanced US and Sonazoid-enhanced 3D US for diagnosing and treating hepatic lesions, especially HCC.

Parametric imaging using contrast-enhanced ultrasound with Sonazoid for hepatocellular carcinoma

PURPOSE

To clarify the usefulness of parametric imaging using contrast-enhanced ultrasound (CE-US) with Sonazoid by comparing parametric images of hepatocellular carcinoma (HCC) with histopathological findings.

METHODS

Two patients with HCCs underwent CE-US with Sonazoid before surgical resection. A single focus point was set at the lower margin of the tumor, and a bolus intravenous injection of Sonazoid (0.5 ml) was administered. Images of the ideal scanning plane were displayed in real-time mode for the early vascular phase. We analyzed these images using prototype PC software. The software watches, pixel by pixel, the increase in the intensity due to the inflow of the microbubbles, and displays colors if the intensity becomes larger than a certain threshold. Parametric images were compared with histopathological findings.

RESULTS

The level of blood flow in the tumor could be visually evaluated using a single image by expressing the detailed hemodynamics of the tumor in terms of differences in color using a time axis appropriate for each case.

CONCLUSIONS

Parametric imaging is a very useful way of facilitating straightforward visualization of the level of blood flow within HCC and the distribution of histopathological findings in single static images.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Secondary hepatic resection as a therapeutic goal in advanced colorectal cancer

Surgery is the only curative option for patients with liver metastases of colorectal cancer, but few patients present with resectable hepatic lesions. Chemotherapy is increasingly used to downstage initially unresectable disease and allow for potentially curative surgery. Standard chemotherapy regimens convert 10%-20% of cases to resectable disease in unselected populations and 30%-40% of those with disease confined to the liver. One strategy to further increase the number of candidates eligible for surgery is the addition of active targeted agents such as cetuximab and bevacizumab to standard chemotherapy. Data from a phase III trial indicate that cetuximab increases the number of patients eligible for secondary hepatic resection, as well as the rate of complete resection when combined with first-line treatment with the FOLFIRI regimen. The safety profiles of preoperative cetuximab or bevacizumab have not been thoroughly assessed, but preliminary evidence indicates that these agents do not increase surgical mortality or exacerbate chemotherapy-related hepatotoxicity, such as steatosis (5-fluorouracil), steatohepatitis (irinotecan), and sinusoidal obstruction (oxaliplatin). Secondary resection is a valid treatment goal for certain patients with initially unresectable liver metastases and an important end point for future clinical trials.

Preparation of targeted microbubbles: ultrasound contrast agents for molecular imaging

Targeted ultrasound contrast agents can be prepared by attaching targeting ligands to the lipid, protein or polymer shell coating of gas-filled microbubbles. These materials are stable on storage, fully biocompatible and can be administered parenterally. Detection of microbubble contrast agents by ultrasound is very efficient (single particles with picogram mass can be visualized). Covalent or noncovalent binding techniques can be used to attach targeting ligands. Ligand-carrying microbubbles adhere to the respective molecular targets in vitro and in vivo. Several biomechanical methods are available to improve targeting efficacy, such as the use of a flexible tether spacer arm between the ligand and the bubble, and the use of folds on the microbubble shell, that project out, enhancing the contact area and increasing the length of the lever arm.

Sonazoid-enhanced sonography for guiding radiofrequency ablation for hepatocellular carcinoma: better tumor visualization by Kupffer-phase imaging and vascular-phase imaging after reinjection

PURPOSE

The purpose of this study was to assess the usefulness of contrast harmonic sonography with a newly developed sonographic contrast agent as a means of guidance for percutaneous radiofrequency (RF) ablation of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

A total of 52 consecutive HCC lesions in 42 patients with HCC who underwent percutaneous RF ablation were included in this study. Altogether, 40 lesions in 35 patients were untreated HCC, and 12 lesions in 7 patients were local tumor progression of an HCC that had already been treated by other methods. We investigated tumors by Kupffer-phase imaging and vascular-phase imaging after reinjection. We performed RF ablation guided by Sonazoid-enhanced sonography using Kupffer-phase imaging and vascular-phase imaging after reinjection.

RESULTS

Conventional sonography identified 30 (57%) of 52 HCCs, whereas Sonazoid-enhanced sonography detected 50 (96%) of 52 HCCs (P < 0.01, McNemar's chi2 test). Complete ablation was achieved at a single session in 48 of 50 tumors.

CONCLUSION

Sonazoid-enhanced sonography is a useful technique for guiding RF ablation of HCCs, even when treating local progression of a previously treated HCC.

Role of Sonazoid-enhanced three-dimensional ultrasonography in the evaluation of percutaneous radiofrequency ablation of hepatocellular carcinoma

OBJECTIVE

We investigated contrast-enhanced three-dimensional ultrasonography (CE 3D US) with contrast agent Sonazoid for evaluating the effect of percutaneous radiofrequency (RF) ablation of hepatocellular carcinomas (HCCs).

METHODS

63 HCCs were treated by US-guided percutaneous RF ablation. CE 3D US after bolus injection of 0.2 mL of Sonazoid was performed 5-7 days before and 1 day after RF ablation. CE 3D computed tomography (CT) was performed 5-7 days before and 1 month after the ablation, and during the follow-up period. Multiplanar images in three orthogonal planes and US/CT angiograms were reconstructed on both modalities. Two blinded observers reviewed the images on both modalities to evaluate the ablation effects.

RESULTS

After RF ablation, the evaluation on CE 3D US and that on CE 3D CT achieved concordance in 61 lesions. Among them, 59 lesions were detected with the absence of tumor vessels and tumor enhancement and evaluated as adequate ablation, and the remaining two lesions were detected with residual tumors. The kappa value for agreement between the findings on the two modalities was 0.65. When 1-month CE 3D CT scans were used as reference standard, the sensitivity, specificity, and accuracy of 1-day CE 3D US for detecting adequate ablation were 97%, 100%, and 97%, respectively.

CONCLUSION

By demonstrating the ablated areas and residual tumors in three dimensions, CE 3D US with Sonazoid was shown to be useful for evaluating the effect of RF ablation of HCCs, and there was good concordance with the results obtained by CE 3D CT.

Sonazoid-enhanced ultrasonography for evaluation of the enhancement patterns of focal liver tumors in the late phase by intermittent imaging with a high mechanical index

OBJECTIVE

The purpose of this study was to evaluate the enhancement patterns of focal liver tumors in the late phase of Sonazoid-enhanced ultrasonography by intermittent imaging with a high mechanical index (MI).

METHODS

A total of 142 patients with 208 lesions, including 109 hepatocellular carcinomas (HCCs), 61 metastases, 30 hemangiomas, and 8 focal nodular hyperplasias (FNHs), were enrolled in this prospective study. Contrast-enhanced ultrasonography with intermittent scanning at 2 frames per second (MI, 0.7-1.2) was conducted in the late phase (>5 minutes after bolus intravenous injection of the perflubutane-based contrast agent Sonazoid; Daiichi Sankyo, Tokyo, Japan). Two blinded readers classified the enhancement patterns of the lesions. The sensitivity, specificity, and positive predictive value (PPV) of the dominant enhancement patterns and inter-reader agreement were assessed.

RESULTS

A combination of diffuse enhancement with intratumoral vessels and intratumoral vessels alone yielded sensitivity of 85% (average of both readers), specificity of 88%, and a PPV of 88% for HCC. For metastasis, a combination of peripheral ringlike enhancement with peritumoral vessels and peripheral ringlike enhancement with intratumoral vessels yielded sensitivity of 79%, specificity of 95%, and a PPV of 85%. For hemangiomas, a combination of peripheral nodular enhancement with peritumoral vessels and peripheral nodular enhancement without peritumoral vessels yielded sensitivity of 75%, specificity of 99%, and a PPV of 92%. Diffuse enhancement with spoked wheel arteries yielded sensitivity of 82%, specificity of 100%, and a PPV of 87% for FNHs. Good inter-reader agreement was achieved.

CONCLUSIONS

Sonazoid-enhanced ultrasonography using intermittent imaging with a high MI can potentially be used for evaluating the enhancement patterns of focal liver tumors in the late phase.