Contrast-enhanced intraoperative ultrasonography using perfluorobutane microbubbles for the enumeration of 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.

A Review of Ultrasound-Mediated Checkpoint Inhibitor Immunotherapy

Over the past decade, immunotherapy has emerged as a major modality in cancer medicine. However, despite its unprecedented success, immunotherapy currently benefits only a subgroup of patients, may induce responses of limited duration and is associated with potentially treatment-limiting side effects. In addition, responses to immunotherapeutics are sometimes diminished by the emergence of a complex array of resistance mechanisms. The efficacy of immunotherapy depends on dynamic interactions between tumour cells and the immune landscape in the tumour microenvironment. Ultrasound, especially in conjunction with cavitation-promoting agents such as microbubbles, can assist in the uptake and/or local release of immunotherapeutic agents at specific target sites, thereby increasing treatment efficacy and reducing systemic toxicity. There is also increasing evidence that ultrasound and/or cavitation may themselves directly stimulate a beneficial immune response. In this review, we summarize the latest developments in the use of ultrasound and cavitation agents to promote checkpoint inhibitor immunotherapy.

Application of Indocyanine Green Fluorescence Imaging for Tumor Localization during Robot-Assisted Hepatectomy

The efficacy of indocyanine green (ICG) fluorescence imaging for visualizing hepatic tumors in robot-assisted hepatectomy (RAH) should be validated. This study included 30 consecutive patients with 33 collective tumors who underwent RAH. ICG was administered at a dose of 0.5 mg/kg before surgery. ICG fluorescence imaging was performed intraoperatively. In total, 28 patients with a combined total of 31 tumors underwent ICG fluorescence imaging. Further, 26 (84%) tumors were identified on hepatic surfaces prior to hepatic transection. The fluorescence signals of eight tumors were detected on hepatic raw surfaces during parenchymal dissection, thereby enabling surgeons to adjust the transection planes to ensure appropriate surgical margins. One patient with intrahepatic cholangiocarcinoma tested positive for cancer cells at the dissected stump of the bile duct. However, in all patients in whom ICG fluorescence imaging was used, negative surgical margins were achieved at the site of the dissected hepatic parenchyma. On the other hand, one of two patients with ICG contraindications had a positive surgical margin surrounding the dissected hepatic parenchyma. The median operative time and volume of blood loss were 259 (range: 124-594) min and 150 (range: 1-1150) mL, respectively. ICG fluorescence imaging facilitates the easy identification of hepatic tumors, even in RAH. Hence, it can be useful for confirming appropriate surgical margins.

Perfluorocarbons: A perspective of theranostic applications and challenges

Perfluorocarbon (PFC) are biocompatible compounds, chemically and biologically inert, and lacks toxicity as oxygen carriers. PFCs nanoemulsions and nanoparticles (NPs) are highly used in diagnostic imaging and enable novel imaging technology in clinical imaging modalities to notice and image pathological and physiological alterations. Therapeutics with PFCs such as the innovative approach to preventing thrombus formation, PFC nanodroplets utilized in ultrasonic medication delivery in arthritis, or PFC-based NPs such as Perfluortributylamine (PFTBA), Pentafluorophenyl (PFP), Perfluorohexan (PFH), Perfluorooctyl bromide (PFOB), and others, recently become renowned for oxygenating tumors and enhancing the effects of anticancer treatments as oxygen carriers for tumor hypoxia. In this review, we will discuss the recent advancements that have been made in PFC's applications in theranostic (therapeutics and diagnostics) as well as assess the benefits and drawbacks of these applications.

Probe electrospray ionization mass spectrometry-based rapid diagnosis of liver tumors

BACKGROUND AND AIM

Prompt differential diagnosis of liver tumors is clinically important and sometimes difficult. A new diagnostic device that combines probe electrospray ionization-mass spectrometry (PESI-MS) and machine learning may help provide the differential diagnosis of liver tumors.

METHODS

We evaluated the diagnostic accuracy of this new PESI-MS device using tissues obtained and stored from previous surgically resected specimens. The following cancer tissues (with collection dates): hepatocellular carcinoma (HCC, 2016-2019), intrahepatic cholangiocellular carcinoma (ICC, 2014-2019), and colorectal liver metastasis (CRLM, 2014-2019) from patients who underwent hepatic resection were considered for use in this study. Non-cancerous liver tissues (NL) taken from CRLM cases were also incorporated into the analysis. Each mass spectrum provided by PESI-MS was tested using support vector machine, a type of machine learning, to evaluate the discriminatory ability of the device.

RESULTS

In this study, we used samples from 91 of 139 patients with HCC, all 24 ICC samples, and 103 of 202 CRLM samples; 80 NL from CRLM cases were also used. Each mass spectrum was obtained by PESI-MS in a few minutes and was evaluated by machine learning. The sensitivity, specificity, and diagnostic accuracy of the PESI-MS device for discriminating HCC, ICC, and CRLM from among a mix of all three tumors and from NL were 98.9%, 98.1%, and 98.3%; 87.5%, 93.1%, and 92.6%; and 99.0%, 97.9%, and 98.3%, respectively.

CONCLUSION

This study demonstrated that PESI-MS and machine learning could discriminate liver tumors accurately and rapidly.

Improved sensitivity and positive predictive value of contrast-enhanced intraoperative ultrasound in colorectal cancer liver metastasis: a systematic review and meta-analysis

BACKGROUND

Surgery is an effective treatment for improving the survival rate of patients with colorectal cancer liver metastases (CRLM). However, accurately determining the resection margin of liver lesions during surgery remains challenging. Therefore, this study aimed to evaluate the sensitivity and predictive value of intraoperative contrast-enhanced ultrasound (CE-IOUS) in CRLM patients undergoing surgery.

METHODS

We performed a literature search of the PubMed, Cochrane Central Register of Controlled Trials, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang, and Weipu databases using the following search terms: metastatic liver cancer, colorectal cancer, sensitivity, contrast-enhanced intraoperative ultrasound, CE-IOUS, colorectal liver metastases, and CRLM. The search period was set from the date of establishment of the database to September 2021. Quality assessment of diagnostic accuracy studies 2 (QUADAS-2) recommended by the Cochrane Collaboration was used to assess the methodological quality of the included studies, and network meta-analysis was performed using Stata 15.0 software.

RESULTS

A total of 10 articles met the inclusion criteria. The meta-analysis results showed that the overall sensitivity and specificity of CE-IOUS were 0.96 [95% confidence interval (CI), 0.95-0.97] and 0.75 (95% CI, 0.70-0.80), respectively. The overall sensitivity and specificity of IOUS were 0.84 (95% CI, 0.82-0.86) and 0.82 (95% CI, 0.77-0.87), respectively. The area under the summary receiving operating characteristic (SROC) curves (AUCs) of CE-IOUS and IOUS were 0.9753 and 0.8590, respectively. The odds ratio (OR) and 95% CI of CE-IOUS changed the surgical margin were 0.205 and 0.071-0.465, P=0.000, the difference was statistically significant.

DISCUSSION

Based on the results of this meta-analysis, CE-IOUS improved the sensitivity and predictive value of CRLM detection compared with IOUS, and is more suitable for intraoperative planning of surgical margins. At present, it is the most sensitive imaging method available, and is recommended for use during liver resection to provide doctors with more reliable information during surgery.

Contrast-Enhanced Intraoperative Ultrasound Improved Sensitivity and Positive Predictive Value in Colorectal Liver Metastasis: a Systematic Review and Meta-Analysis

BACKGROUND

The diagnostic accuracy of imaging modalities in colorectal cancer liver metastases (CRLM) has improved in recent years, therefore the role of current imaging techniques needs to be defined.

OBJECTIVE

The aim of this study was to assess the diagnostic performance of magnetic resonance imaging, preoperative imaging (magnetic resonance imaging or computed tomography), intraoperative ultrasound, and contrast-enhanced intraoperative ultrasound in the detection of CRLM.

MATERIALS AND METHODS

Eligible trials published before 30 March 2020 were identified from the EMBASE, PubMed, Web of Science, and Cochrane Library databases, and descriptive and quantitative data were extracted. Study quality was evaluated for the identified studies and a random-effects model was used to determine the integrated diagnosis estimation. Meta-regression was implemented to explore the possible contributors to heterogeneity.

RESULTS

Overall, 13 studies were included for analysis, comprising 682 patients with a total of 2303 liver lesions. The pooled sensitivity, specificity, and diagnostic odds ratio of contrast-enhanced intraoperative ultrasound were 0.94 (95% confidence interval [CI] 0.89-0.97), 0.83 (95% CI 0.67-0.92), and 79 (95% CI 32-196), respectively. The overall weighted area under the curve was 0.96 (95% CI 0.94-0.97). In univariate meta-regression analysis, disappearing liver metastasis, contrast agent, and Kupffer phase were the potent sources of heterogeneity; however, in multivariate meta-regression, no definite variable was the source of the study heterogeneity.

CONCLUSION

Contrast-enhanced intraoperative ultrasound demonstrated a high sensitivity and specificity for screening CRLM.

Identification of Glisson's Capsule Invasion During Hepatectomy for Colorectal Liver Metastasis by Contrast-Enhanced Ultrasonography Using Perflubutane

BACKGROUND

Glisson invasion by CLM is associated with a risk of margin-positive resection, leading to poor long-term outcomes after hepatectomy. This study was performed to evaluate the efficacy of intraoperative ultrasonography (IOUS) for the diagnosis of Glisson's capsule invasion by colorectal liver metastasis (CLM).

METHODS

This prospective study involved 50 consecutive patients undergoing hepatectomy for CLM. Preoperatively, all patients had undergone gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI). During hepatectomy, a contrast agent (perflubutane) was intravenously injected and Glisson invasion was estimated based on three characteristic findings: a tumor thrombus, peripheral dilatation, and border irregularity/caliber change. The diagnostic abilities of the preoperative and intraoperative imaging studies were evaluated based on pathological examinations of resected specimens.

RESULTS

Among 187 CLMs resected, pathological examinations proved Glisson invasion in 24 tumors (13%). IOUS revealed a tumor thrombus in 3 tumors (1.6%), peripheral dilatation in 4 (2.1%), and border irregularity and/or caliber change in 24 (12.8%). The sensitivity and specificity of IOUS with any of the above three findings for diagnosis of Glisson invasion was 79% and 96%, respectively, while preoperative EOB-MRI detected Glisson invasion in only four tumors (sensitivity/specificity, 17%/100%). The cutoff value of caliber change for diagnosis of Glisson invasion was set at 140% by receiver operating characteristic analysis. The R0 resection rates were not significantly different between patients with (82%) and without (85%) Glisson invasion.

CONCLUSIONS

Identification of characteristic findings (tumor thrombus, peripheral dilatation, and border irregularity/caliber change) by contrast-enhanced IOUS is useful for the prediction of Glisson invasion by CLM.

Open and/or laparoscopic one-stage resections of primary colorectal cancer and synchronous liver metastases: An observational study

One-stage resections of primary colorectal cancer and liver metastases have been reported to be feasible and safe. Minimally invasive approaches have become more common for both colorectal and hepatic surgeries. This study aimed to investigate outcomes of these combined surgical procedures among different approaches.We retrospectively analyzed patients diagnosed as having primary colorectal cancer with synchronous liver metastases and who underwent 1-stage primary resection and hepatectomy with curative intent in our hospital. According to the surgical approach for the primary tumor and hepatic lesions, namely open laparotomy (Op) or laparoscopic approach (Lap), patients were classified into Op-Op, Lap-Op (laparoscopic colorectal resection plus open hepatectomy), and Lap-Lap groups, respectively. Clinicopathological factors were reviewed, and short- and long-term outcomes were compared among the groups.The Op-Op, Lap-Op, and Lap-Lap groups comprised 36, 18, and 17 patients, respectively. The superior/posterior hepatic segments were more frequently resected via an open approach. There was no laparoscopic major hepatectomy. The median volume of intraoperative blood loss was smaller in the Lap-Lap and Lap-Op groups (290 and 270 mL) than in the Op-Op group (575 mL, P = .008). The hospital stay after surgery was shorter in the Lap-Lap and Lap-Op groups (median: 17 days and 15 days, vs 19 days for the Op-Op group, P = .033). The postoperative complication rates and survivals were similar among the groups.Application of laparoscopy to 1-stage resections of primary colorectal cancer and liver metastases may offer advantages of enhanced recovery from surgical treatment, given appropriate patient selection.

A new rapid diagnostic system with ambient mass spectrometry and machine learning for colorectal liver metastasis

BACKGROUND

Probe electrospray ionization-mass spectrometry (PESI-MS) can rapidly visualize mass spectra of small, surgically obtained tissue samples, and is a promising novel diagnostic tool when combined with machine learning which discriminates malignant spectrum patterns from others. The present study was performed to evaluate the utility of this device for rapid diagnosis of colorectal liver metastasis (CRLM).

METHODS

A prospectively planned study using retrospectively obtained tissues was performed. In total, 103 CRLM samples and 80 non-cancer liver tissues cut from surgically extracted specimens were analyzed using PESI-MS. Mass spectra obtained by PESI-MS were classified into cancer or non-cancer groups by using logistic regression, a kind of machine learning. Next, to identify the exact molecules responsible for the difference between CRLM and non-cancerous tissues, we performed liquid chromatography-electrospray ionization-MS (LC-ESI-MS), which visualizes sample molecular composition in more detail.

RESULTS

This diagnostic system distinguished CRLM from non-cancer liver parenchyma with an accuracy rate of 99.5%. The area under the receiver operating characteristic curve reached 0.9999. LC-ESI-MS analysis showed higher ion intensities of phosphatidylcholine and phosphatidylethanolamine in CRLM than in non-cancer liver parenchyma (P < 0.01, respectively). The proportion of phospholipids categorized as monounsaturated fatty acids was higher in CRLM (37.2%) than in non-cancer liver parenchyma (10.7%; P < 0.01).

CONCLUSION

The combination of PESI-MS and machine learning distinguished CRLM from non-cancer tissue with high accuracy. Phospholipids categorized as monounsaturated fatty acids contributed to the difference between CRLM and normal parenchyma and might also be a useful diagnostic biomarker and therapeutic target for CRLM.

Impact on operative outcomes of laparoscopic simultaneous resection of colorectal cancer and synchronous liver metastases

INTRODUCTION

The efficacy of laparoscopic simultaneous resection of primary colorectal cancer and synchronous colorectal liver metastases (SCRLM) remains unclear.

METHODS

We retrospectively evaluated data from 258 patients who had undergone simultaneous curative resection of the primary tumor and SCRLM from 2006 to 2017. We compared surgical outcomes between open, hybrid (laparoscopic colorectal resection and open hepatectomy), and pure laparoscopic approaches. Surgical outcomes were also evaluated between the open hepatectomy (OH) group (ie, open/hybrid surgery) and the laparoscopic hepatectomy (LH) group (ie, pure laparoscopic surgery) in 141 patients later in the study period (2013-2017), when the clinical indications for laparoscopic hepatectomy were restricted to simple wedge resection and/or left lateral sectionectomy in our center.

RESULTS

The pure laparoscopic approach was associated with significantly less intraoperative blood loss and a significantly shorter postoperative hospital stay than the open and hybrid approaches. Late in the study period, operative outcomes in the LH group (n = 37) were more favorable than for the OH group (n = 104) in terms of intraoperative blood loss and postoperative hospital stay. In patients with rectal cancer, however, earlier postoperative recovery in the LH group did not differ significantly from the OH group.

CONCLUSION

Laparoscopic simultaneous resection of SCRLM with the primary tumor by simple hepatectomy is safe and may enhance patients' postoperative recovery, especially in patients with colon cancer.

Colorectal liver metastases: Current management and future perspectives

The liver is the commonest site of metastatic disease for patients with colorectal cancer, with at least 25% developing colorectal liver metastases (CRLM) during the course of their illness. The management of CRLM has evolved into a complex field requiring input from experienced members of a multi-disciplinary team involving radiology (cross sectional, nuclear medicine and interventional), Oncology, Liver surgery, Colorectal surgery, and Histopathology. Patient management is based on assessment of sophisticated clinical, radiological and biomarker information. Despite incomplete evidence in this very heterogeneous patient group, maximising resection of CRLM using all available techniques remains a key objective and provides the best chance of long-term survival and cure. To this end, liver resection is maximised by the use of downsizing chemotherapy, optimisation of liver remnant by portal vein embolization, associating liver partition and portal vein ligation for staged hepatectomy, and combining resection with ablation, in the context of improvements in the functional assessment of the future remnant liver. Liver resection may safely be carried out laparoscopically or open, and synchronously with, or before, colorectal surgery in selected patients. For unresectable patients, treatment options including systemic chemotherapy, targeted biological agents, intra-arterial infusion or bead delivered chemotherapy, tumour ablation, stereotactic radiotherapy, and selective internal radiotherapy contribute to improve survival and may convert initially unresectable patients to operability. Currently evolving areas include biomarker characterisation of tumours, the development of novel systemic agents targeting specific oncogenic pathways, and the potential re-emergence of radical surgical options such as liver transplantation.

Comparison of laparoscopic ultrasound and liver-specific magnetic resonance imaging for staging colorectal liver metastases

BACKGROUND

Intraoperative liver ultrasound appears superior to liver-specific contrast-enhanced magnetic resonance imaging (MRI) to stage colorectal liver metastases (CRLMs). Most of the data come from studies on open surgery. Laparoscopic ultrasound (LUS) is technically demanding and its reliability is poor investigated. Aim of the study was to assess the accuracy of LUS staging for CRLMs compared to MRI.

METHODS

All patients with CRLMs scheduled for laparoscopic liver resection (LLR) between 01/2010 and 06/2019 who underwent preoperative MRI were considered for the study. LUS and MRI performance was compared on a patient by patient basis. Reference standards were final pathology and 6 months follow-up results.

RESULTS

Amongst 189 LLR for CRLMs, 146 met inclusion criteria. Overall, 391 CRLMs were preoperatively detected by MRI. 24 new nodules in 16 (10.9%) patients were found by LUS and resected. Median diameter of new nodules was 5.5 mm (2-10 mm) and 10 (41.6%) were located in the hepatic dome. Pathology confirmed 17 newly detected malignant nodules (median size 4 mm) in 11 (7.5%) patients. Relationships between intrahepatic vessels and tumours differed between LUS and MRI in 9 patients (6.1%). Intraoperative surgical strategy changed according LUS findings in 19 (13%) patients, requiring conversion to open approach in 3 (15.8%) of them. The sensitivity of LUS was superior to MRI (93.1% vs 85.6% whilst specificity was similar (98.6% MRI vs 96.5% LUS).

CONCLUSIONS

Laparoscopic liver ultrasound improves liver staging for CRLMs compared to liver-specific MRI.

The history of liver surgery: Achievements over the past 50 years

We reviewed the progress made in the field of liver surgery over the past 50 years. The widespread use and improved outcomes of the hepatectomy were, primarily, due to pioneer surgeons who were responsible for technological advances and rapid improvements in the safety of the procedure in the last century. These advances included the hepatic functional evaluation used to determine the safety limit of liver resections, the introduction of intraoperative ultrasonography, and the development of innovative techniques such as portal vein embolization to increase the remnant liver volume. Cadaveric liver transplantation has been attempted since 1963. However, the clinical outcomes only began improving and becoming acceptable in the 1970s-1980s due to refinements in technology and the development of new immunosuppressants. Partial liver transplantation from living donors, which was first attempted in 1988, required further technological innovation and sophisticated perioperative management plans. Moreover, these developments allowed for further overall improvements to take place in the field of liver surgery. Since the turn of the century, advances in computation and imaging technology have made it possible for safer and more elaborate surgeries to be performed. In Japan, preoperative 3-dimensional simulation technology has been covered by health insurance since 2012 and is now widely used. An urgent need for real-time navigation tools will develop in the future. Indocyanine green (ICG) fluorescence imaging was first used in 2007 and has led to the creation of a new surgical concept known as fluorescence navigation surgery. Laparoscopic surgery and robotic surgery have solved the issue of large incisions, which used to be a major drawback of open liver surgery; however, further improvements are required in order to achieve the level of safety and accuracy observed during open liver resection when performing all minimally invasive procedures. In the near future, liver surgery will become more precise and less invasive due to substantial progress including the development of navigation surgery, cancer imaging, and minimally invasive surgery. This overview of the history of liver surgery over the past 50 years may provide useful insights for further innovation in the next 50 years.

Liver resection for recurrent hepatocellular carcinoma after radiofrequency ablation therapy

AIM

Although radiofrequency ablation (RFA) is an effective local treatment of hepatocellular carcinoma (HCC), local recurrence is relatively frequent. We aimed to elucidate the validity of salvage liver resection for recurrent HCC after RFA.

METHODS

Patients who underwent liver resection for recurrent HCC after RFA (LR after RFA) and those who underwent second liver resection for recurrent HCC (second LR) were included. The short-term outcomes were compared between the two groups. The survival rates between the two groups were compared after propensity-score matching to adjust for the variables, including patient background, liver function, and tumor status.

RESULTS

Major resection was frequently carried out in the LR after RFA group, but there was no significant difference both in operative data and complication rate between LR after RFA (n = 54) and second LR (n = 266) groups. After a median follow-up period of 1.8 years (range, 0.2-10.5), the median overall survival was 4.4 years (95% confidence interval [CI], 2.2 - not applicable) and 5.6 years (95% CI, 4.5-7.3; P = 0.023) in the LR after RFA group (n = 54) and second LR group (n = 54), respectively, and recurrence-free survival was 1.3 years (0.4-2.2) and 1.2 years (0.5-1.8, P = 0.469), respectively. The only independent factor for overall survival of the LR after RFA group was local recurrence (hazard ratio, 2.73; 1.06-9.00).

CONCLUSIONS

Salvage liver resection of recurrent HCC after RFA could be recommended due to the safety of the procedure, especially in patients without local tumor progression after RFA.

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

BACKGROUND AND OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Contrast-Enhanced Ultrasound of the Liver: Optimizing Technique and Clinical Applications

OBJECTIVE

The purpose of this article is to review the general principles, technique, and clinical applications of contrast-enhanced ultrasound of the liver.

CONCLUSION

Proper technique and optimization of contrast-enhanced ultrasound require a balance between maintaining the integrity of the microbubble contrast agent and preserving the ultrasound signal. Established and emerging applications in the liver include diagnosis of focal lesions, aiding ultrasound-guided intervention, monitoring of therapy, and aiding surgical management.

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

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

Intraoperative Ultrasound as a Screening Modality for the Detection of Liver Metastases during Resection of Primary Colorectal Cancer - A Systematic Review

Colorectal cancer (CRC) is one of the most common cancer diseases worldwide. One in 4 patients with CRC will have a disseminated disease at the time of diagnosis and often in the form of synchronous liver metastases. Studies suggest that up to 30% of patients have non-recognized hepatic metastases during primary surgery for CRC. Intraoperative ultrasonography examination (IOUS) of the liver to detect liver metastases was considered the gold standard during open CRC surgery. Today laparoscopic surgery is the standard procedure, but laparoscopic ultrasound examination (LUS) is not performed routinely. Aim To perform a systematic review of the test performance of IOUS and LUS regarding the detection of synchronous liver metastases in patients undergoing surgery for primary CRC. Method The literature was systematically reviewed using the search engines: PubMed, Cochrane, Embase and Google. 21 studies were included in the review and the key words: intraoperative ultrasound, laparoscopic ultrasound, staging colon and rectum cancer. Results Intraoperative ultrasound showed a higher sensitivity, specificity, positive predictive value and overall accuracy for the detection liver metastases during surgery for primary CRC, compared to preoperative imaging modalities (ultrasound, computed tomography (CT) and contrast-enhanced computed tomography (CE-CT)). LUS showed a higher detection rate for liver metastases compared to CT, CE-CT and magnetic resonance imaging (MRI). Conclusion This systematic review found that both IOUS and LUS had a higher detection rate regarding liver metastases during primary CRC surgery, especially liver metastases<10 mm in diameter, when compared to US, CT, CE-CT and MRI.

Applications of fusion-fluorescence imaging using indocyanine green in laparoscopic hepatectomy

BACKGROUND

Indocyanine green (ICG)-fluorescence imaging has been developed for real-time identification of hepatic tumors and segmental boundaries during hepatectomy. Fusion ICG-fluorescence imaging (real-time visualization of pseudocolor-fluorescence signals on white-light color images) may serve as a reliable navigation tool especially in laparoscopic hepatectomy, in which gross inspection and palpation are limited.

METHODS

The study population consisted of 41 patients undergoing laparoscopic hepatectomy. Hepatic tumors were identified by fluorescence imaging following the preoperative intravenous administration of ICG (0.5 mg/kg body weight). To visualize hepatic perfusion and segmental boundaries, ICG (1.25 mg) was injected intravenously during surgery, following closure of the proximal portal pedicle. A laparoscopic imaging system, which enabled superimposition of the pseudocolor-fluorescence images on white color images, was used for the fusion ICG-fluorescence imaging.

RESULTS

Among the 53 malignant tumors resected, fusion ICG-fluorescence imaging revealed 45 nodules (85%), including three nodules of colorectal liver metastasis unidentifiable by white-light color images or intraoperative ultrasonography. It also delineated the segmental boundaries on the hepatic raw surfaces as well as on the phrenic/visceral surfaces in all 12 patients evaluated using this technique.

CONCLUSIONS

Fusion imaging enhances the feasibility of intraoperative ICG-fluorescence imaging in the identification of hepatic tumors and segmental boundaries. It may therefore help surgeons in the safe and accurate completion of laparoscopic hepatectomies.

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.

Survival benefit of repeat resection of successive recurrences after the initial hepatic resection for colorectal liver metastases

BACKGROUND

Relapse is common after the resection of colorectal liver metastases (CLM); however, the optimal treatment for such recurrent disease remains uncertain. We investigated whether repeat resections for successive recurrences of CLM provide survival benefit on the postrecurrence survival.

METHODS

We reviewed patients who underwent upfront, curative resection for CLM at our center during a 15-year period. Of these, 263 patients who had not received any other perioperative treatment for the metastases were eligible for our analysis. The recurrence-free survival (RFS0) after the initial hepatic resection and after the first (n = 108), second (n = 43), and third (n = 15) repeat resections for recurrent disease were assessed (RFS1-3). The overall survival after the initial hepatic resection and the postrecurrence survival (n = 198) also was assessed.

RESULTS

The median RFS0 was 0.8 years, and RFS1, RFS2, and RFS3 were 1.3, 1.1, and 2.0 years, respectively. The hazard ratio for RFS for the first, second, and third resections versus the initial hepatic resection was 0.9 (95% confidence interval [95% CI] 0.7-1.1; P = .34), 1.00 (95% CI 0.7-1.4; P = .97), and 0.7 (95% CI 0.4-1.3; P = .29). The 5-year and 10-year OS rates were 54.6% and 42.2%, and the 5-year and 10-year postrecurrence survival was 34.3% and 28.6%, respectively.

CONCLUSION

Repeat resection in patients with recurrent disease after CLM resection is beneficial, offering the potential for cure in a small proportion of patients with recurrent disease.

Disappearing liver metastases from colorectal cancer: impact of modern imaging modalities

BACKGROUND

Chemotherapy is often used before a resection for colorectal liver metastases. After chemotherapy, metastases may disappear on cross-sectional imaging but residual metastatic disease may still exist. The aim of this retrospective study was to investigate the impact of new advancements in imaging technology such as magnetic resonance imaging (MRI) with liver-specific contrast (Gd-EOB-DTPA) and contrast-enhanced intra-operative ultrasound (CE-IOUS) on disappearing liver metastases (DLM).

METHODS

Twenty-nine patients with one or more DLM undergoing surgical exploration were included. Pre-operative imaging consisted of contrast-enhanced multi-detector computed tomography (MDCT) and/or MRI with liver-specific contrast. At surgery, CE-IOUS was used when tumours known from pre-chemotherapy imaging were not found by inspection or intra-operative ultrasound.

RESULTS

Patients presented 66 DLM. At surgical exploration, 42 DLM were identified and treated (64%). CE-IOUS detected one additional DLM not found by intra-operative ultrasound. For metastases ≤10 mm on histological analysis, imaging sensitivities for MRI and MDCT before surgery but after chemotherapy were 26/49 (53%) and 24/66 (36%), respectively.

CONCLUSION

A majority of DLM are identified during surgery using intra-operative ultrasound, with only little additional value of CE-IOUS. The sensitivities of post-chemotherapy imaging modalities for small metastases are low in the setting of DLM. For surgical planning, an optimized pre-chemotherapy imaging is essential.

Predicting early intrahepatic recurrence after curative resection of colorectal liver metastases with molecular markers

BACKGROUND

The aim of this case-control study was to identify clinicopathological factors and test three relevant biomarkers for their ability to predict early intrahepatic recurrence after curative liver resection for colorectal liver metastases (CLM).

METHODS

Of the 184 patients with CLM undergoing hepatectomy between January 2007 and December 2009, thirty patients had intrahepatic disease recurrence within 6 months. The control group was randomly selected from a cohort of patients between April 1997 and December 2005 who have survived without disease recurrence after CLM resection for over 5 years. Both groups were matched for size of metastasis greater than 5.0 cm, the presence of multiple metastases, and synchronous versus metachronous CLM. The final study population consisted of 60 patients with CLM undergoing R0 hepatectomy, 30 of whom had early intrahepatic-only recurrences (study group) and 30 patients without recurrence for more than 5 years (control group). Both groups were analyzed and compared for the presence of clinical factors and expression levels of CD133, survivin, and Bcl-2 within tumor tissue.

RESULTS

Characteristics of patients were similar between the two groups except primary tumor location and administration of postoperative chemotherapy. Expression level of CD133 and survivin were significantly increased in tumors of patients with recurrence compared to patients without recurrence. On multivariate analysis high tumor expression levels of CD133 (odds ratio [OR] 14.7, confidence interval [CI] 1.8-121.3, p = 0.012) and survivin (OR 9.5, CI 2.1-44.3, p = 0.004) and postoperative chemotherapy (OR 4.8, CI 1.01-22.9, p = 0.049) were independent factors associated with early intrahepatic recurrence.

CONCLUSIONS

Tumor expression levels of CD133 and survivin may be a useful predictor of early intrahepatic recurrence after hepatectomy for CLM. Administration of postoperative chemotherapy may prevent early intrahepatic recurrence.

Advances in Assessment and Planning for Surgical Treatment of Hepatocellular Carcinoma

This chapter covers recent important topics relevant to ensuring safe liver resection. In particular, preoperative and intraoperative techniques, such as 3-dimensional CT, intraoperative ultrasonography with contrast agent and fluorescence imaging using indocyanine green are reportedly useful and have been applied to liver resection and liver transplantation. We, herein, describe the performance of liver resection under the guidance of these techniques and present tips for more accurate intraoperative tumor detection and safer surgical procedures.

Anatomical Liver Resections Guided by 3-Dimensional Parenchymal Staining Using Fusion Indocyanine Green Fluorescence Imaging

OBJECTIVE

To investigate the feasibility and efficacy of anatomical liver resection (ALR) guided by fused images comprising a macroscopic view and indocyanine green fluorescence imaging (fusion IGFI).

BACKGROUND

ALR is established in treating hepatocellular carcinoma or other malignancies to achieve curability and functional preservation. However, the conventional demarcation technique (CDT) marks only the organ surface and sometimes fails to execute a completely valid demarcation.

METHODS

Twenty-four consecutive ALRs for focal liver malignancy were studied using fusion IGFI. Indocyanine green was administered systemically after selective inflow clamping in 12 patients or by portal puncture and direct injection in 12 patients, and we compared demarcation findings between fusion IGFI and CDT. The strength of contrast between target and nontarget areas was quantitatively calculated as contrast index and compared between IGFI and CDT according to injection technique or state of the liver surface.

RESULTS

Fusion IGFI achieved valid demarcation in 23 of 24 patients (95.8%), whereas CDT achieved valid demarcation in only 10 patients (41.7%) (P < 0.0001). The contrast index of fusion IGFI was 0.81 (0.18-2.51), which was significantly higher than that of CDT at 0.12 (0.01-0.42) (P < 0.0001), and the same result was obtained regardless of the injection method or liver surface state used. ALR was conducted referring to 3-dimensional staining of target parenchyma, with no related perioperative adverse events.

CONCLUSIONS

Fusion IGFI is a safe imaging technique for ALR that attained valid 3-dimensional parenchymal demarcation with better feasibility and clearer demarcation than CDT.

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.

Contrast-enhanced ultrasound in liver cancer

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

Reappraisal of the inferior right hepatic vein preserving liver resection

BACKGROUND

To resect tumors infiltrating to the right hepatic vein at its root, right hemihepatectomy or that following portal vein embolization (PVE) is applied. If the IRHV is sizable, the IRHV preserving liver resection can be another option.

METHODS

Between 1994 and 2007, the IRHV preserving liver resection was performed in 21 patients (IRHV group). The short-term outcomes after surgery of them p.

RESULTS

There were no mortality and no significant difference between the IRHV and RH groups concerning the blood loss, the morbidity rates and the duration of hospital stay. The median operation time was shorter in the IRHV group than in the RH group (393 vs. 480 min, p = 0.0409). The median weight of resected specimen of the IRHV group was 293 g (range: 20-982), which was significantly lighter than that of the RH group (median: 680 g [250-4,300], p < 0.001). The median percentage of resected volume to standard liver volume was significantly smaller in the IRHV group than in the RH group (25.8 vs. 52.2%, p < 0.001).

CONCLUSION

The IRHV preserving liver resection remains a safe and useful procedure.

Differential diagnosis of liver tumours using intraoperative real-time tissue elastography

Background

Real-time tissue elastography is an innovative tool that informs the surgeon about tissue elasticity by applying the principle of ultrasonography. The aim of this study was to investigate the accuracy of intraoperative real-time tissue elastography (IORTE) for the detection and characterization of liver tumours.

Methods

Between October 2010 and November 2011, IORTE was performed for liver lesions after the completion of routine B-mode intraoperative ultrasonography (IOUS). The elasticity images of all tumours, except those of cysts, were classified into six categories according to modified criteria (types 1–6), according to the degree of strain contrast with the surrounding liver. The concordance of IORTE with pathological examination of the tumour, B-mode IOUS and clinical diagnosis after follow-up was assessed.

Results

Images were obtained from 92 hepatocellular carcinomas (HCCs), 92 adenocarcinomas, 19 other malignant tumours and 18 benign tumours in 158 patients. Using a minilinear probe, 73 of 88 HCCs were classified as having a ‘HCC pattern’ (type 3, 4 or 5), resulting in a sensitivity of 83·0 per cent, a specificity of 67·2 per cent and an accuracy of 73·7 per cent. Some 66 of 90 adenocarcinomas were classified as ‘adenocarcinoma pattern’ (type 6), resulting in a sensitivity of 73·3 per cent, specificity of 95·1 per cent and accuracy of 85·9 per cent. IORTE detected seven new lesions (8 per cent).

Conclusion

IORTE is useful for the detection and characterization of liver tumours.

"Vanishing liver metastases"-A real challenge for liver surgeons

Expanded surgical intervention in colorectal liver metastasis (LM) and improved chemotherapy led to increasing problem of disappearing liver metastases (DLM). Treatment of those continues to evolve and poses a real challenge for HPB surgeons. This review discusses a clinical approach to DLM, emphasizing crucial steps in clinical algorithm. Particular issues such as imaging, intraoperative detection and surgical techniques are addressed. A step-by-step algorithm is suggested.

Photoacoustic tomography of human hepatic malignancies using intraoperative indocyanine green fluorescence imaging

Recently, fluorescence imaging following the preoperative intravenous injection of indocyanine green has been used in clinical settings to identify hepatic malignancies during surgery. The aim of this study was to evaluate the ability of photoacoustic tomography using indocyanine green as a contrast agent to produce representative fluorescence images of hepatic tumors by visualizing the spatial distribution of indocyanine green on ultrasonographic images. Indocyanine green (0.5 mg/kg, intravenous) was preoperatively administered to 9 patients undergoing hepatectomy. Intraoperatively, photoacoustic tomography was performed on the surface of the resected hepatic specimens (n = 10) under excitation with an 800 nm pulse laser. In 4 hepatocellular carcinoma nodules, photoacoustic imaging identified indocyanine green accumulation in the cancerous tissue. In contrast, in one hepatocellular carcinoma nodule and five adenocarcinoma foci (one intrahepatic cholangiocarcinoma and 4 colorectal liver metastases), photoacoustic imaging delineated indocyanine green accumulation not in the cancerous tissue but rather in the peri-cancerous hepatic parenchyma. Although photoacoustic tomography enabled to visualize spatial distribution of ICG on ultrasonographic images, which was consistent with fluorescence images on cut surfaces of the resected specimens, photoacoustic signals of ICG-containing tissues decreased approximately by 40% even at 4 mm depth from liver surfaces. Photoacoustic tomography using indocyanine green also failed to identify any hepatocellular carcinoma nodules from the body surface of model mice with non-alcoholic steatohepatitis. In conclusion, photoacoustic tomography has a potential to enhance cancer detectability and differential diagnosis by ultrasonographic examinations and intraoperative fluorescence imaging through visualization of stasis of bile-excreting imaging agents in and/or around hepatic tumors. However, further technical advances are needed to improve the visibility of photoacoustic signals emitted from deeply-located lesions.

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.

Visualization of subcapsular hepatic malignancy by indocyanine-green fluorescence imaging during laparoscopic hepatectomy

BACKGROUND

Although laparoscopic hepatectomy has increasingly been used to treat cancers in the liver, the accuracy of intraoperative diagnosis may be inferior to that of open surgery because the ability to visualize and palpate the liver surface during laparoscopy is relatively limited. Fluorescence imaging has the potential to provide a simple compensatory diagnostic tool for identification of cancers in the liver during laparoscopic hepatectomy.

METHODS

In 17 patients who were to undergo laparoscopic hepatectomy, 0.5 mg/kg body weight of indocyanine green (ICG) was administered intravenously within the 2 weeks prior to surgery. Intraoperatively, a laparoscopic fluorescence imaging system obtained fluorescence images of its surfaces during mobilization of the liver.

RESULTS

In all, 16 hepatocellular carcinomas (HCCs) and 16 liver metastases (LMs) were resected. Of these, laparoscopic ICG fluorescence imaging identified 12 HCCs (75%) and 11 LMs (69%) on the liver surfaces distributed over Couinaud's segments 1-8, including the 17 tumors that had not been identified by visual inspections of normal color images. The 23 tumors that were identified by fluorescence imaging were located closer to the liver surfaces than another nine tumors that were not identified by fluorescence imaging (median [range] depth 1 [0-5] vs. 11 [8-30] mm; p < 0.001).

CONCLUSIONS

Like palpation during open hepatectomy, laparoscopic ICG fluorescence imaging enables real-time identification of subcapsular liver cancers, thus facilitating estimation of the required extent of hepatic mobilization and determination of the location of an appropriate hepatic transection line.

Surgical management of disappearing colorectal liver metastases

BACKGROUND

Owing to expanded surgical indications for colorectal liver metastasis (CRLM) and improved systemic therapy, hepatic surgeons are increasingly faced with the problem of disappearing (no longer visible on imaging) liver metastasis (DLM).

METHODS

A review of relevant studies was performed. Studies that reported on DLM associated with preoperative chemotherapy for CRLM were identified, and data were synthesized and tabulated. The PubMed database was searched for relevant articles published between January 2000 and December 2012.

RESULTS

A complete response on imaging does not necessarily equate with a complete clinical or pathological response. Rather, residual macroscopic disease is found in about 25-45 per cent of patients at the time of operation. Even among patients with a complete pathological response, long-term remission occurs in only 20-50 per cent of those treated with systemic therapy. A durable response of DLM is more common following the use of hepatic artery infusion therapy.

CONCLUSION

Liver resection should include all original sites of disease if possible.

Near-infrared fluorescence-guided resection of colorectal liver metastases

BACKGROUND

The fundamental principle of oncologic surgery is the complete resection of malignant cells. However, small tumors are often difficult to find during surgery using conventional techniques. The objectives of this study were to determine if optical imaging, using a contrast agent already approved for other indications, could improve hepatic metastasectomy with curative intent, to optimize dose and timing, and to determine the mechanism of contrast agent accumulation.

METHODS

The high tissue penetration of near-infrared (NIR) light was exploited by use of the FLARE (Fluorescence-Assisted Resection and Exploration) image-guided surgery system and the NIR fluorophore indocyanine green in a clinical trial of 40 patients undergoing hepatic resection for colorectal cancer metastases.

RESULTS

A total of 71 superficially located (< 6.2 mm beneath the liver capsule) colorectal liver metastases were identified and resected using NIR fluorescence imaging. Median tumor-to-liver ratio was 7.0 (range, 1.9-18.7) and no significant differences between time points or doses were found. Indocyanine green fluorescence was seen as a rim around the tumor, which is shown to be entrapment around cytokeratin 7-positive hepatocytes compressed by the tumor. Importantly, in 5 of 40 patients (12.5%, 95% confidence interval = 5.0-26.6), additional small and superficially located lesions were detected using NIR fluorescence, and were otherwise undetectable by preoperative computed tomography, intraoperative ultrasound, visual inspection, and palpation.

CONCLUSIONS

NIR fluorescence imaging, even when used with a nontargeted, clinically available NIR fluorophore, is complementary to conventional imaging and able to identify missed lesions by other modalities.

Segmental and lobar administration of drug-eluting beads delivering irinotecan leads to tumour destruction: a case-control series

BACKGROUND

Irinotecan-loaded drug-eluting beads represent a novel drug delivery method that allows for the locoregional delivery of irinotecan to colorectal liver metastases (CRLM). The method has shown impressive response rates. However, the pathological response to this treatment has not previously been demonstrated.

METHODS

Patients with easily resectable CRLM were treated with drug-eluting beads delivering irinotecan (DEBIRI) 4 weeks prior to resection. Pathological tumour response was graded using a validated system. The intraoperative detection of previously unidentified disease allowed for the assessment of pathological responses directly attributable to bead treatment.

RESULTS

In Patient 1, segmental embolization of the target lesion in segment VIII resulted in 100% necrosis (0% viability). An untreated lesion in segment IV was found to be 30% viable. In Patient 2, subsegmental embolization of the target lesion in segment VI resulted in 60% necrosis and 40% fibrosis (0% viability). An untreated lesion in segment VI remained 60% viable. In Patient 3, lobar embolization of the target lesion in segment II resulted in 0% viability. Two further lesions within the treated hemiliver, both with 0% viability, and one lesion in the untreated hemiliver with 45% viability were discovered at laparotomy.

CONCLUSIONS

This series demonstrates the effectiveness of DEBIRI in the treatment of CRLM. High rates of tumour destruction are possible, even with the proximal lobar administration of DEBIRI. Lobar administration appears to be an appropriate method of delivery for integration into future therapeutic regimens.