Factors determining the sensitivity of intraoperative ultrasonography in detecting colorectal liver metastases in the modern era

Assessment and treatment considerations for patients with colorectal liver metastases: AHPBA consensus guideline and update for surgeons

BACKGROUND

Colorectal cancer most commonly metastasizes to the liver. While various treatment strategies have been developed, surgical management of these patients has vital implications on the prognosis and survival of this group of patients. There remains a need for a consensus guideline regarding the surgical evaluation and management of patients with colorectal liver metastases (CRLM).

METHODS

This review article is a consensus guideline established by the members of the AHPBA Professional Standards Committee, as an amalgamation of existent literature and a guide to surgeons managing this complex disease.

RESULTS

These guidelines reports the benefits and shortcomings of various diagnostic modalities including imaging and next-generation sequencing in the management of patients with CRLM. While surgery has established survival benefits in patients with resectable disease, this report notes the importance of treatment sequencing with non-surgical modalities as well as between colon and liver resection. Finally, the guidelines address the various treatment modalities for patients with unresectable disease, that may have significant impact on survival.

CONCLUSION

CRLM is a complex diagnosis which warrants multidisciplinary approach with early surgical involvement in both assessment and management of the disease, to optimize patient outcomes and survival.

Value and prognostic factors of repeat hepatectomy for recurrent colorectal liver metastasis

BACKGROUND

More than 50% of patients with colorectal cancer develop liver metastases. Hepatectomy is the preferred treatment for resectable liver metastases. This review provides a perspective on the utility and relevant prognostic factors of repeat hepatectomy in recurrent colorectal liver metastasis (CRLM).

DATA SOURCES

The keywords "recurrent colorectal liver metastases", "recurrent hepatic metastases from colorectal cancer", "liver metastases of colorectal cancer", "repeat hepatectomy", "repeat hepatic resection", "second hepatic resection", and "prognostic factors" were used to retrieve articles published in the PubMed database up to August 2020. Additional articles were identified by a manual search of references from key articles.

RESULTS

Despite improvements in surgical methods and perioperative chemotherapy, recurrence remains common in 37%-68% of patients. Standards or guidelines for the treatment of recurrent liver metastases are lacking. Repeat hepatectomy appears to be the best option for patients with resectable metastases. The commonly reported prognostic factors after repeat hepatectomy were R0 resection, carcinoembryonic antigen level, the presence of extrahepatic disease, a short disease-free interval between initial and repeat hepatectomy, the number (> 1) and size (≥ 5 cm) of hepatic lesions, requiring blood transfusion, and no adjuvant chemotherapy after initial hepatectomy. The median overall survival after repeat hepatectomy ranged from 19.3 to 62 months, and the 5-year overall survival ranged from 21% to 73%. Chemotherapy can act as a test for the biological behavior of tumors with the goal of avoiding unnecessary surgery, and a multimodal approach involving aggressive chemotherapy and repeat hepatectomy might be the treatment of choice for patients with early recurrent CRLM.

CONCLUSIONS

Repeat hepatectomy is a relatively safe and effective treatment for resectable recurrent CRLM. The presence or absence of prognostic factors might facilitate patient selection to improve short- and long-term outcomes.

Artificial intelligence for identification of focal lesions in intraoperative liver ultrasonography

PURPOSE

Intraoperative ultrasonography (IOUS) of the liver is a crucial adjunct in every liver resection and may significantly impact intraoperative surgical decisions. However, IOUS is highly operator dependent and has a steep learning curve. We describe the design and assessment of an artificial intelligence (AI) system to identify focal liver lesions in IOUS.

METHODS

IOUS images were collected during liver resections performed between November 2020 and November 2021. The images were labeled by radiologists and surgeons as normal liver tissue versus images that contain liver lesions. A convolutional neural network (CNN) was trained and tested to classify images based on the labeling. Algorithm performance was tested in terms of area under the curves (AUCs), accuracy, sensitivity, specificity, F1 score, positive predictive value, and negative predictive value.

RESULTS

Overall, the dataset included 5043 IOUS images from 16 patients. Of these, 2576 were labeled as normal liver tissue and 2467 as containing focal liver lesions. Training and testing image sets were taken from different patients. Network performance area under the curve (AUC) was 80.2 ± 2.9%, and the overall classification accuracy was 74.6% ± 3.1%. For maximal sensitivity of 99%, the classification specificity is 36.4 ± 9.4%.

CONCLUSIONS

This study provides for the first time a proof of concept for the use of AI in IOUS and show that high accuracy can be achieved. Further studies using high volume data are warranted to increase accuracy and differentiate between lesion types.

Ultrasound-based navigation for open liver surgery using active liver tracking

PURPOSE

Despite extensive preoperative imaging, intraoperative localization of liver lesions after systemic treatment can be challenging. Therefore, an image-guided navigation setup is explored that links preoperative diagnostic scans and 3D models to intraoperative ultrasound (US), enabling overlay of detailed diagnostic images on intraoperative US. Aim of this study is to assess the workflow and accuracy of such a navigation system which compensates for liver motion.

METHODS

Electromagnetic (EM) tracking was used for organ tracking and movement of the transducer. After laparotomy, a sensor was attached to the liver surface while the EM-tracked US transducer enabled image acquisition and landmark digitization. Landmarks surrounding the lesion were selected during patient-specific preoperative 3D planning and identified for registration during surgery. Endpoints were accuracy and additional times of the investigative steps. Accuracy was computed at the center of the target lesion.

RESULTS

In total, 22 navigated procedures were performed. Navigation provided useful visualization of preoperative 3D models and their overlay on US imaging. Landmark-based registration resulted in a mean fiducial registration error of 10.3 ± 4.3 mm, and a mean target registration error of 8.5 ± 4.2 mm. Navigation was available after an average of 12.7 min.

CONCLUSION

We developed a navigation method combining ultrasound with active liver tracking for organ motion compensation, with an accuracy below 10 mm. Fixation of the liver sensor near the target lesion compensates for local movement and contributes to improved reliability during navigation. This represents an important step forward in providing surgical navigation throughout the procedure.

TRIAL REGISTRATION

This study is registered in the Netherlands Trial Register (number NL7951).

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.

Intraoperative (Contrast-Enhanced) Ultrasound Has the Highest Diagnostic Accuracy of Any Imaging Modality in Resection of Colorectal Liver Metastases

AIM

Defining sensitivity, specificity, diagnostic accuracy for detection of colorectal liver metastases in imaging compared to intraoperative assessment. Defining a cutoff, where accuracy of detection is impaired.

METHODS

Prospective single-institution clinical trial (clinicaltrials.gov: NCT01522209). Patients underwent CEUS, MDCT, and 3 Tesla EOB-MRI within 2 weeks preoperatively. Intraoperative palpation, IOUS, and CEIOUS were performed. A patient and lesion-based database was analyzed for accuracy of detection of CEUS, CT, MRI, and Palp/IOUS/CEIOUS combined read. Histology was standard of reference.

RESULTS

Forty-seven high tumor load (mean 5, 4 lesions) patients were analyzed. Histopathology confirmed 264 lesions (245 malignant: 19 benign). Accuracy for detection of all lesions: CEUS 63%, CT 71%, MRI 92%, and PALP/IOUS/CEIOUS 98%. ROC analysis for lesion size showed severe impairment of accuracy in lesion detection smaller than 5mm. Intraoperative imaging was not impaired by lesion size. Patient-based analysis revealed a change of resection plan after IOUS/CEIOUS in 35% of patients.

CONCLUSION

At 5-mm lesion size, preoperative imaging shows a drop in accuracy of detection. In patients with multiple lesions, addition of MRI to MDCT seems useful. Accuracy of intraoperative ultrasound is not impacted by lesion size and should be mandatory. CEIOUS can improve intraoperative decision-making.

TRIAL REGISTRATION

Study registered with clinicaltrials.gov : NCT01522209.

The use of intra-operative ultrasound in gynecological surgery: a review

Ultrasound is a readily available, safe and portable imaging modality that is widely applied in gynecology. However, there is limited guidance for its use intra-operatively especially with complex gynecological procedures. This narrative review examines the existing literature published on the use of intraoperative ultrasound (IOUS) in benign gynecology and in gynecological oncology. We searched for the following terms: ‘intraoperative,’ ‘ultrasonography,’ ‘gynecology’ and ‘oncology’ using Pubmed/Medline. IOUS can minimize complications and facilitate difficult benign gynecological procedures. There is also a role for its use in gynecological oncology surgery and fertility-sparing surgery. The use of IOUS in gynecological surgery is an emerging field which improves visualization in the surgical field and aids completion of minimally invasive techniques.

Ultrasound (US) is a portable and safe imaging method that uses high frequency sound waves to visualize structures within the body. While most US examinations are done outside the body there is an emerging field which uses US devices within the body during surgery to aid complex procedures. This review examines the published literature on this technique in benign gynecology and in gynecological oncology. This review demonstrates the use of intraoperative US improves visualization and minimizes surgical complications.

Operative Microwave Ablation for the Multimodal Treatment of Neuroendocrine Liver Metastases

Background and Purpose: Operative microwave ablation (MWA) is a safe modality for treating hepatic tumors. The aim of this study is to present our 10-year, single-center experience of operative MWA for neuroendocrine liver metastases (NLM). Methods: A single-institution retrospective review of patients who underwent operative MWA for NLM was performed (2008-2018). Demographics, primary tumor site, operative approach, combined surgical operations, and carcinoid symptoms were recorded. Clinical outcomes for major complications, readmission, and mortality were analyzed 30 days postoperatively. Postablation imaging was evaluated for incomplete ablation/missed lesions, and surveillance imaging reviewed for local, regional, and metastatic recurrence. Results: Of the 50 patients (166 targeted lesions) who received MWA for NLM, 41 (82%) were treated with a minimally invasive approach, and 22 (44%) underwent MWA concomitant with hepatectomy and/or primary tumor resection. Within the study cohort 70% of patients were treated with curative intent with a 77% (27/35) success rate. Carcinoid symptoms were reported in 40% (20/50) of patients preoperatively, and MWA treatment improved symptoms in 19/20 patients. Incomplete ablation occurred in 1/166 treated lesions. Recurrence-free survival at 1 and 5 years was 86% and 28%, respectively. Overall survival at 1 and 5 years was 94% and 70%, respectively (median follow-up 32 months, range 0-116 months). Conclusion: Operative MWA is a versatile modality, which can be safe and effectively performed alone or combined with hepatectomy for NLM, preferably using a minimally invasive approach, to achieve symptom control and possibly improve survival.

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.

Hepatic resection in children: highlighted and revisited steps

Background

Hepatectomy in children deserves exhaustive preoperative and intraoperative tools to define the anatomy, minimize blood loss, and confirm adequacy of liver tissue left. The aim of this study is to report our experience in surgical management of liver tumors.

Results

All liver resections performed in Ain-Shams University Hospital, by the same team, between July 2013 and June 2018 were retrospectively reviewed. Data related to basic demographics, indication for resection, methods of parenchymal resection, blood loss, hospital stay, morbidity, and mortality was collected. The study included 27 patients who underwent different types of hepatectomies. There was a male predominance. Age ranged from 6 months to 13 years. Weight ranged from 5.7 to 33.7 kg. Total operative time ranged from 68 to 322 min, while resection time ranged from 34 to 144 min. Blood loss ranged from 53 to 259 ml. Surgical morbidities included five patients with minor biliary leak, three patients had surgical site infection, and one patient had torsion of the remnant liver necessitating repositioning. Recurrence of the mass was faced in three patients with hepatoblastoma. There were two mortalities; one occurred as a sequela of massive intraoperative bleeding and the other took place due to postoperative hepatic insufficiency.

Conclusion

For a safe hepatectomy, thorough familiarity of the hepatic segmental anatomy together with the various techniques for parenchymal resection and vascular control is fundamental. Complications such as biliary leak and torsion of remnant can be easily avoided by simple measures.

Intraoperative Ultrasound Staging for Colorectal Liver Metastases in the Era of Liver-Specific Magnetic Resonance Imaging: Is It Still Worthwhile?

Background

To assess the efficacy of intraoperative ultrasound (IOUS) compared with liver-specific magnetic resonance imaging (MRI) in patients with colorectal liver metastases (CRLMs).

Methods

From January 2010 to December 2017, 721 patients underwent MRI as a part of preoperative workup within 1 month before hepatectomy and were considered for the study. Early intrahepatic recurrence (relapse at cut surface excluded) was assessed 6 months after the resection and was considered as residual disease undetected by IOUS and/or MRI. IOUS and MRI performance was compared on a patient-by-patient basis. Long-term results were also studied.

Results

A total of 2845 CRLMs were detected by MRI, and the median number of CRLMs per patient was 2 (1–31). Preoperative chemotherapy was administered in 489 patients (67.8%). In 177 patients, 379 new nodules were intraoperatively found and resected. Among 379 newly identified nodules, 317 were histologically proven CRLMs (11.1% of entire series). The median size of new CRLMs was 6 ± 2.5 mm. Relationships between intrahepatic vessels and tumors differed between IOUS and MRI in 128 patients (17.7%). The preoperative surgical plan was intraoperatively changed for 171 patients (23.7%). Overall, early intrahepatic recurrence occurred in 8.7% of cases. To assess the diagnostic performance, 24 (3.3%) recurrences at the cut surface were excluded; thus, 5.4% of early relapses were considered for analysis. The sensitivity of IOUS was superior to MRI (94.5% vs 75.1%), while the specificity was similar (95.7% vs 95.9%). Multivariate analysis at the hepatic dome or subglissonian and mucinous histology revealed predictive factors of metastases missing at MRI. The 5-year OS (52.1% vs 37.8%, p=0.006) and DF survival (45.1% vs 33%, p=0.002) were significantly worse among patients with new CRLMs than without.

Conclusions

IOUS improves staging in patients undergoing resection for CRLMs even in the era of liver-specific MRI. Intraoperative detection of new CRLMs negatively affects oncologic outcomes.

Impact of Genetics on Neoadjuvant Therapy with Complete Pathological Response in Metastatic Colorectal Cancer: Case Report and Review of the Literature

Treatment of colorectal metastatic cancer is still challenging, despite recent improvements in chemotherapy. A genetic cancer profile, such as the KRAS (Kirsten rat sarcoma) gene status, plays a key role in individualized tailored therapy. Molecular targeted therapy added to neo-adjuvant chemotherapy can achieve a better pathological response and prolong survival. Pathological complete response of colorectal cancer stage IV is rare. A 47-year-old female patient presented with rectal adenocarcinoma and three liver metastases (cT3d/4, N2, Ml). After seven cycles of Bevacizumab and CAPOX in neoadjuvant setting, we noted more than 70.0% regression of metastases and complete regression of the primary tumor. We performed low anterior resection of rectum and synchronous subsegmental resection of S3, because the other two lesions were not detectable. Pathology revealed complete response of the primary and also secondary tumors. After 8 months, diagnostic tests did not show any sign of recurrence and the remaining liver lesions disappeared. Colorectal cancer is a heterogeneous disease and it is necessary to identify patients who are at-risk of recurrence and suitable for neoadjuvant therapy. Genetic biomarkers play an important role in metastatic colorectal cancer treatment. Because of the mutated KRAS gene, Bevacizumab was added to cytotoxic therapy achieving a complete pathological response of primary tumor and metastasis. This case is unique because all reported cases with similar results, described staged surgery and one of reverse staged surgery, but with similar results. This neoadjuvant therapy has extraordinary results for colorectal cancer stage IV and can help disease-free and long-term survival.

Can echogenic appearance of neuroendocrine liver metastases on intraoperative ultrasonography predict tumor biology and prognosis?

BACKGROUND

Determining the biologic behavior of neuroendocrine liver metastases (NELM) is important when managing patients with this disease. We sought to define the intraoperative ultrasound (IOUS) characteristics of NELM and correlate with tumor biology and prognosis.

METHODS

Prospective data on patients who underwent IOUS and surgical intervention for NELM were collected, with images digitally recorded, blindly reviewed, and scored for echogenicity. Association between sonographic appearance, clinicopathologic factors and long-term outcomes was analyzed.

RESULTS

A total of 216 lesions from 65 patients were analyzed, with IOUS identifying at least one additional metastasis than preoperative imaging in 41 patients (63.1%) with subsequent change of surgical strategy in 14 patients (21.5%). Most NELM appeared hypoechoic (49.1%) on IOUS, while 38.9% demonstrated hyperechogenicity and 12% isoechogenicity. Hypoechoic lesions were associated with poorly-differentiated tumor (p = 0.005) and smaller tumor size (p = 0.004). Patients with hypoechoic metastases demonstrated significantly shorter median disease-free survival compared with isoechoic or hyperechoic lesions (9 vs 20 vs 18 months, p = 0.049).

DISCUSSION

In addition to improved tumor detection of NELM, IOUS was found to be associated with features of tumor biology, specifically tumor grade and risk-of-recurrence. Echogenicity should be considered a potential prognostic factor in the management of patients with neuroendocrine tumors.

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.

Pathological complete response after neoadjuvant chemotherapy for rectal cancer with synchronous multiple liver metastases: a report of an unusual case

Background

Systemic chemotherapy for stage IV colorectal cancer has advanced markedly in the recent years. We report an unusual case of 13 synchronous liver metastases for which a pathological complete response was achieved with neoadjuvant chemotherapy (NAC) consisting of a combination of 5-fluorouracil (5-FU), oxaliplatin, leucovorin (mFOLFOX6), and bevacizumab.

Case presentation

A 44-year-old man was diagnosed with colorectal cancer with synchronous liver metastases. We resected the primary rectal tumor first. Further, after providing NAC for hepatic metastases, lateral segmentectomy and partial resection of the liver were performed. The subsequent result was compatible with a complete pathological response. The postoperative course was uneventful, and the patient is currently alive 5 years after the first surgery without evidence of recurrence and without adjuvant chemotherapy.

Conclusions

For patients with initially resectable colorectal liver metastases, the survival benefits of NAC are still unclear. We report a rare case of 13 synchronous liver metastatic lesions from rectal cancer with a complete pathological response after neoadjuvant bevacizumab-containing chemotherapy.

Minimally Invasive Liver Surgery for Hepatic Colorectal Metastases

Minimally invasive surgery has been cautiously introduced in surgical oncology over the last two decades due to a concern of compromised oncological outcomes. Recently, it has been adopted in liver surgery for colorectal metastases. Colorectal cancer is a major cause of cancer-related death in the USA. In addition, liver metastasis is the most common site of distant disease and its resection improves survival. While open resection was the standard of care, laparoscopic liver surgery has become the standard of care for minor liver resections. Laparoscopic liver surgery provides equivalent oncological outcomes with better perioperative results compared to open liver surgery. Robotic liver surgery has been introduced as it is believed to overcome some of the limitations of laparoscopy. Finally, laparoscopic radio-frequency ablation and microwave coagulation can be used as adjuncts in minimally invasive surgery to complement or replace surgical resection when not possible.

Intraoperative ultrasonography and surgical strategy in hepatic resection: What difference does it make?

BACKGROUND

With modern advancements in preoperative imaging for liver surgery, intraoperative ultrasonography (IOUS) may be perceived as superfluous. Our aim was to determine if IOUS provides new information that changes surgical strategy in hepatic resection.

METHODS

We retrospectively analyzed 121 consecutive liver resections performed at a single institution. Preoperative computed tomography and/or magnetic resonance imaging determined the initial surgical strategy. The size, location and number of lesions were compared between IOUS and preoperative imaging. Reviewing the operative report helped determine if new IOUS findings led to changes in surgical strategy. Pathology reports were analyzed for margins.

RESULTS

Of 121 procedures analyzed, IOUS was used in 88. It changed the surgical plan in 15 (17%) cases. Additional tumours were detected in 10 (11%) patients. A change in tumour size and location were detected in 2 (2%) and 3 (4%) patients, respectively. Surgical plans were altered in 7 (8%) cases for reasons not related to IOUS. There was no significant difference (p = 0.74) in average margin length between the IOUS and non-IOUS groups (1.09 ± 1.18 cm v. 1.18 ± 1.05 cm).

CONCLUSION

Surgical strategy was altered owing to IOUS results in a substantial number of cases, and IOUS-guided resection planes resulted in R0 resections in nearly all procedures. The best operative plan in hepatic resection includes IOUS.

Segmentation of Uterus Using Laparoscopic Ultrasound by an Image-Based Active Contour Approach for Guiding Gynecological Diagnosis and Surgery

In laparoscopic gynecologic surgery, ultrasound has been typically implemented to diagnose urological and gynecological conditions. We applied laparoscopic ultrasonography (using Esaote 7.5~10MHz laparoscopic transducer) on the retrospective analyses of 42 women subjects during laparoscopic extirpation and excision of gynecological tumors in our hospital from August 2011 to August 2013. The objective of our research is to develop robust segmentation technique for isolation and identification of the uterus from the ultrasound images, so as to assess, locate and guide in removing the lesions during laparoscopic operations. Our method enables segmentation of the uterus by the active contour algorithm. We evaluated 42 in-vivo laparoscopic images acquired from the 42 patients (age 39.1 ± 7.2 years old) and selected images pertaining to 4 cases of congenital uterine malformations and 2 cases of pelvic adhesions masses. These cases (n = 6) were used for our uterus segmentation experiments. Based on them, the active contour method was compared with the manual segmentation method by a medical expert using linear regression and the Bland-Altman analysis (used to measure the correlation and the agreement). Then, the Dice and Jaccard indices are computed for measuring the similarity of uterus segmented between computational and manual methods. Good correlation was achieved whereby 84%-92% results fall within the 95% confidence interval in the Student t-test) and we demonstrate that the proposed segmentation method of uterus using laparoscopic images is effective.

A novel ultrasound based approach for lesion segmentation and its applications in gynecological laparoscopic surgery

Laparoscopic ultrasound (LUS) has been widely utilized as a surgical aide in general, urological, and gynecological applications. Our study summarizes the clinical applications of laparoscopic ultrasonography in laparoscopic gynecologic surgery. Retrospective analyses were performed on 42 women subjects using laparoscopic surgery during laparoscopic extirpation and excision of gynecological tumors in our hospital from August 2011 to August 2013. Specifically, the Esaote 7.5 × 10 MHz laparoscopic transducer was used to detect small residual lesions, as well as to assess, locate and guide in removing the lesions during laparoscopic operations. The findings of LUS were compared with those of preoperative trans-vaginal ultrasound, postoperative, and pathohistological examinations. In addition, a novel method for lesion segmentation was proposed in order to facilitate the laparoscopic gynecologic surgery. In our experiment, laparoscopic operation was performed using a higher frequency and more close to pelvic organs via laparoscopic access. LUS facilitates the ability of gynaecologists to find small residual lesions under laparoscopic visualization and their accurate diagnosis. LUS also helps to locate residual lesions precisely and provides guidance for the removal of residual tumor and eliminate its recurrence effectively. Our experiment provides a safer and more valuable assistance for clinical applications in laparoscopic gynecological surgery that are superior to trans-abdominal ultrasound and trans-vaginal ultrasound.

Usefulness of intraoperative ultrasonography in liver resections due to colon cancer metastasis

INTRODUCTION

Intraoperative ultrasonography (IOUS) of the liver has been used both as an aid for intraoperative anatomical definition and for the detection of new lesions. The present study aimed to evaluate the impact of IOUS and to identify factors that can predict the detection of new lesions intraoperatively.

METHODS

In this observational and prospective study, with a cross-sectional design, patients with colorectal cancer metastases who underwent hepatectomy were selected. Abdominal computed tomography, magnetic resonance imaging, and positron emission tomography were the preoperative evaluation tests. All patients underwent IOUS performed by the same surgeon. The intraoperative findings were compared with the preoperative tests results.

RESULTS

In total, 56 hepatectomies were evaluated. Half of the patients were men, with a mean age of 57 (30-85) years. New lesions were found intraoperatively in 12 patients (21.4% of cases) and were detected on both palpation and ultrasonography in 11 of these patients. Ultrasonography helped to revise the surgical plans by providing additional information in 35.7% of cases. On multivariate analysis, the presence of more than 4 preoperative nodules was predictive of the intraoperative occurrence of new lesions.

CONCLUSIONS

IOUS remains the only way to evaluate the relationships between tumors, liver vascular structures, and bile ducts intraoperatively. Alone, IOUS was not useful for identifying new lesions intraoperatively, as all new lesions were also detected on palpation. The number of lesions diagnosed on preoperative tests influenced the probability of identifying new lesions intraoperatively. There may be additional influential factors.

The current role of intraoperative ultrasound during the resection of colorectal liver metastases: A retrospective cohort study

INTRODUCTION

Liver resections with negative margins improve survival in patients with colorectal liver metastases (CRLM). Intraoperative ultrasound (IOUS) is a valuable tool that gives information about lesions that ultimately changes surgical strategy to ensure complete removal, which subsequently improves disease free survival (DFS).

METHODS

A retrospective review of patients who underwent a resection for CRLM from 2009 to 2012 was completed to determine the impact of IOUS.

RESULTS

A total of 103 patients had a hepatic resection for CRLM. All patients had preoperative imaging to assist with operative planning. IOUS was performed in 72 cases. Surgical strategy changed in 31 (43.1%) cases with IOUS, compared to three (9.7%) with no IOUS (P < 0.001). A new lesion was detected in 13 (18.1%) of the cases. A higher proportion of nonanatomic liver resections were performed in the IOUS group (N = 27, 37.5%) compared to the non-IOUS group (N = 6, 19.4%) (P = 0.07).

CONCLUSION

Achievement of a negative resection margin was comparable between the two groups. However, there was a trend toward improved DFS in the IOUS group. Despite advances in preoperative imaging, IOUS demonstrates utility in providing novel information that allows removal of the entire tumor burden, using parenchymal-preserving techniques when feasible, leading to improved DFS.

Total anatomical laparoscopic liver resection of segment 4 (S4), extended S4, and subsegments S4a and S4b for hepatocellular carcinoma

BACKGROUND

When a tumor is located in segment 4 (S4), it is preferable to perform only limited resection of S4, even in laparoscopic surgery. Here we describe anatomical laparoscopic S4, subdivision of S4 (S4a and S4b), and extended S4 segmentectomy for hepatocellular carcinoma (HCC), using the Glissonian pedicle transection method for each, and evaluate the feasibility of laparoscopic liver resection (LLR) for tumors located in S4.

PATIENTS AND METHODS

Among 417 patients who underwent LLR for malignant tumors between March 2003 and February 2014, we performed retrospective analysis of the clinical and perioperative outcomes of 10 patients who underwent anatomical liver resection for tumors located in the S4 area of the liver.

RESULTS

Total laparoscopic anatomic liver resection (S4, extended S4, and S4a and S4b segmentectomies) were performed in 10 patients. There was no open conversion or postoperative mortality. The mean operation time was 316.5 minutes (range, 175-460 minutes), and mean estimated blood loss was 592 mL (range, 100-1600 mL). An intraoperative transfusion was necessary in 2 (20%) of the 10 patients. All patients had negative resection margins. Three patients (30%) had postoperative complications (intraabdominal fluid collection). The mean postoperative hospital stay was 7.7 days (range, 3-13 days). The median follow-up period was 18 months. Intrahepatic recurrence occurred in 2 (20%) of the 10 patients, which was managed by radiofrequency ablation with transarterial chemoembolization in 1 patient and by transarterial chemoembolization alone in the other patient.

CONCLUSIONS

Total laparoscopic anatomical S4, extended S4, or S4a or S4b segmentectomy is a feasible procedure for HCC. The Glissonian pedicle transection method is an effective technique for rapid and safe control and subdivision of the S4 pedicle that facilitates anatomical laparoscopic S4, extended S4, and S4a and S4b segmentectomy.

Ultrasound-guided laparoscopic liver resections

BACKGROUND

Intraoperative liver ultrasound has an established role in liver surgery to complete staging and to guide resection. The same performances should be expected by laparoscopic ultrasound (LUS).

METHODS

LUS is first performed to identify relationships between tumor and vasculo-biliary pedicles. The planes where the main vascular structures run are marked on the liver surface. Parenchymal transection is performed and each vessel recognized during LUS exploration is divided.

RESULTS

From 01/2009 to 10/2013, in 61 out of 742 liver resections (8.2 %), a laparoscopic approach was attempted. The conversion rate was 9.8 % (six patients). No conversion was related to bleeding or intraoperative complications. The remnant 55 patients were affected by benign lesions in 11 cases and malignant tumors in 44. The resections included 3 left hepatectomies, 14 bisegmentectomies Sg2-3, 5 segmentectomies, and 38 wedge resections. Associated procedures were performed in eight patients (14.5 %), including four colorectal resections. Median duration of surgery was 150 min (60-345 min). Median operative blood loss was 100 mL (0-500 mL). Median size of resected tumor was 2.5 cm (0.9-8 cm). Median surgical margin in oncological resections was 7 mm (0-50 mm). Postoperative complications occurred in four patients (7.2 %), all grade 2 according to Dindo classification. No liver-related morbidity occurred. Median length of hospital stay was 5 days (3-9 days).

CONCLUSIONS

Ultrasound-guided liver resections can be performed by laparoscopic approach with the same accuracy than open surgery.

Early recurrence after liver resection for colorectal metastases: risk factors, prognosis, and treatment. A LiverMetSurvey-based study of 6,025 patients

PURPOSE

The aims of this study were to assess the risk of early recurrence after liver resection for colorectal metastases (CRLM) and its prognostic value; identify early recurrence predictive factors; clarify the effect of perioperative chemotherapy on its occurrence; and elucidate the best early recurrence management.

METHODS

Patients of the LiverMetSurvey registry who underwent complete liver resection (R0/R1) between 1998 and 2009 were reviewed. Early recurrence was defined as any recurrence that occurred within 6 months after resection.

RESULTS

A total of 6,025 patients were included; 2,734 (45.4 %) had recurrence, including 639 (10.6 %) early recurrences. Early recurrence was mainly hepatic (59.5 vs. 54.4 % for late recurrences; p = 0.023). Independent risk factors of early recurrence were: T3-4 primary tumor (p = 0.0002); synchronous CRLM (p = 0.0001); >3 CRLM (p < 0.0001); 0-mm margin liver resection (p = 0.003); and associated intraoperative radiofrequency ablation (p = 0.0005). Response to preoperative chemotherapy (complete/partial) and administration of adjuvant chemotherapy reduced early recurrence risk (p = 0.003 and p < 0.0001, respectively). Intraoperative ultrasonography reduced hepatic early recurrence rate (p = 0.025). Early recurrence negatively affected prognosis: 5-year survival 26.9 versus 49.4 % for the late recurrence group (p < 0.0001, median follow-up 34.4 months). Overall, 234 (36.6 %) patients with early recurrence underwent re-resection. These patients had survival rates higher than non-re-resected patients (5-year survival 47.2 vs. 8.9 %; p < 0.0001) and similar to re-resected patients for late recurrence (48.7 %). Chemotherapy before early recurrence resection improved later survival (5-year survival 61.5 vs. 43.7 %; p = 0.028).

CONCLUSIONS

Early recurrence risk is enhanced for extensive disease after poor preoperative disease control and inadequate surgical treatment, but is reduced after adjuvant chemotherapy. Although early recurrence negatively affects prognosis, re-resection may restore better survival. Chemotherapy before early recurrence resection is advocated.

Combined liver and multivisceral resections

Background. Combined liver and multivisceral resections are infrequent procedures, which demand extensive experience and considerable surgical skills. Methods. An electronic search of literature related to this topic published before June 2013 was performed. Results. There is limited scientific evidence of the feasibility and clinical outcomes of these complex procedures. The majority of these cases are simultaneous resections of colorectal tumors with liver metastases. Combined liver and multivisceral resections can be performed with acceptable postoperative morbidity and mortality rates only in carefully selected patients. Conclusion. Lack of experience in these aggressive surgeries justifies a careful selection of patients, considering their comorbidities.

Hepatocellular carcinoma and cholangiocarcinoma: an update

Hepatocellular carcinoma (HCC) is the third most common cause of cancer worldwide and is rising in incidence. Ultrasound is the preferred modality for screening high-risk patients for HCC because it detects clinically significant nodules, widespread availability and lower cost. HCC does not require a biopsy for diagnosis if specific imaging criteria are fulfilled. Transarterial chemoembolization (TACE) is the most common modality used to treat HCC followed by ablation. Cholangiocarcinoma (CCA) is increasing in incidence and the second most common primary malignancy of the liver. There is no effective screening strategy for CCA although magnetic resonance imaging and carbohydrate antigen 19-9 (CA 19-9) are commonly used without proven benefit. Therapy for CCA is challenging and resection, when possible, is the mainstay of therapy. Gemcitabine in combination with cisplatin or biologics may offer a modest survival benefit. Liver transplantation for CCA is associated with reasonable survival in select cases. Molecular diagnostics offer the potential to develop personalized approaches in the management of HCC and CCA.

Intraoperative liver ultrasound still affects surgical strategy for patients with colorectal metastases in the modern era

BACKGROUND

The present study was designed to evaluate the role of intraoperative ultrasound (IOUS) in intrahepatic staging and the impact on surgical strategy for patients with colorectal liver metastases (CRLM).

METHODS

The study included 515 patients who had undergone liver resection for CRLM at two tertiary care referral centers. Data from a prospectively collected database were retrospectively analysed. Early intrahepatic recurrence was assessed at 3 and 6 months after resection and was considered as residual disease undetected by IOUS. Performance of imaging modalities was compared by analysis of studies on individual patients.

RESULTS

A total of 1,370 liver metastases were detected preoperatively with a median of 3 imaging modalities. MRI and PET were performed in 51 and 42 % of the patients, respectively. Median number of days between last imaging and surgery was 18. Contrast-enhanced IOUS was performed in 136 patients (26.4 %). Intraoperatively, 293 new nodules were found in 132 patients: on histology 280 were CRLM (17.6 %). Surgical strategy was changed in 140 patients (27.2 %). On multivariate analysis synchronous and bilobar metastases ≥ 3 in number, BMI ≥ 30, and time between last imaging and surgery longer than 18 days resulted in predictive factors indicating new nodules detected by IOUS. Early intrahepatic recurrences were 3.7 and 7.9 % at 3 and 6 months. Performance of CT, MRI, FDG-PET, and intraoperative staging was compared: sensitivity was 63.6, 68.8, 53.6, and 92 % and specificity was 91, 92.3, 95.8, and 97.8 %, respectively

CONCLUSIONS

The use of IOUS continues to be mandatory for correct staging of patients with CRLM undergoing liver resection.

Recurrence after microwave ablation of liver malignancies: a single institution experience

BACKGROUND

Microwave ablation (MWA) is increasingly used to achieve local control for liver tumours. This study sought to examine a monocentric experience with MWA, with a primary hypothesis that primary tumour histology was a significant predictor of early recurrence.

METHODS

Retrospective single-institution review identified consecutive patients with liver tumours treated by MWA. Cox proportional hazards models assessed significance of prognostic variables.

RESULTS

Seventy-two patients (43 female, 60%) underwent 83 MWA procedures for 157 tumours. Tumour histologies included hepatocellular cancer (10 operations), colorectal metastases (39), metastatic carcinoid (20) and other (14). The median tumour size was 2.0 cm. A concomitant liver resection was performed in 50 cases (60%). Crude peri-operative morbidity and mortality rates were 16% and 1%, respectively. The median follow-up was 16 months. Ablations were complete for 149 out of 157 tumours (95%). The median overall and recurrence-free survivals were 36 and 18 months, respectively. There was no difference in time to recurrence between the primary tumour types. In multivariable models, recurrence-free survival was independently associated with the use of neoadjuvant [hazard ratio (HR): 2.90, 95% confidence interval (CI): 1.09-7.76, P = 0.034] and adjuvant chemotherapy (HR: 0.36, 95% CI: 0.15-0.82, P = 0.016).

CONCLUSIONS

MWA is a safe and feasible approach for local control of liver tumours. While chemotherapy administration was associated with time to recurrence after MWA, larger studies are needed to corroborate these findings.

Intraoperative imaging

Intraoperative image is a rapidly expanding field encompassing many applications that use a multitude of technologies. Some of the these applications have been in use for many years and are firmly embedded in, and indispensable to, clinical practice (e.g. the use of X-ray to locate foreign bodies during surgery or oocyte retrieval under ultrasound guidance. In others, the application may have been in use in one discipline but not yet fully explored in another. Examples include the use of intraoperative ultrasound with or without contrast enhancement for the detection of hepatic metastases not identified preoperatively, and the effect of such additional information on the ultimate operative procedure. Intraoperative identification of sentinel lymph nodes has been explored in many specialties to a varying extent, with the aim of fine tuning and avoiding unnecessary surgery. In both these instances, we do not know the long-term effect of these interventions on patient survival or quality of life. In this chapter, we will explore the available evidence on these applications and current advances in the new technology in general, with a specific focus on gynaecology.

Comparison of laparoscopic and open intraoperative ultrasonography for staging liver tumours

BACKGROUND

Laparoscopic liver surgery must reproduce open surgical steps. Intraoperative ultrasonography (IOUS) is mandatory, but reliability of laparoscopic IOUS has been poorly evaluated. The aim of this study was to compare laparoscopic versus open IOUS in staging liver tumours.

METHODS

All patients scheduled for liver resection between September 2009 and March 2011 were considered. Inclusion criteria were primary and metastatic tumours. Exclusion criteria were: hilar/gallbladder cholangiocarcinoma, ten or more lesions, repeat resection, laparoscopic hepatectomy, adhesions and unresectability. Following percutaneous ultrasonography and thoracoabdominal computed tomography (CT), and on indication contrast-enhanced (CE) liver magnetic resonance imaging (MRI) and/or positron emission tomography (PET)-CT, patients were scheduled for laparoscopy, laparoscopic IOUS, then laparotomy, open IOUS and Partial hepatectomy. Data were collected prospectively. Reference standards were final pathology and 6-month follow-up results.

RESULTS

Sixty-five patients were included, who had a median of 3 preoperative imaging studies (ultrasonography/CT 100 per cent, CE-MRI 67 per cent, PET-CT 54 per cent). A total of 119 lesions were diagnosed. Laparoscopic IOUS detected 22 additional lesions (+18·5 per cent) in 14 patients. Open IOUS detected two additional lesions, but did not confirm four lesions; overall 20 additional lesions (+16·8 per cent) were detected in ten patients. Pathology confirmed 14 newly detected malignant nodules (+11·8 per cent) in eight patients. After 6 months ten new nodules were identified in six patients. The sensitivity of preoperative imaging, laparoscopic IOUS and open IOUS was 83·1, 92·3 and 93·0 per cent respectively; accuracy was 79, 82 and 88 per cent. In comparison with open IOUS, the sensitivity and accuracy of laparoscopic IOUS were 98·6 and 94 per cent.

CONCLUSION

Laparoscopic IOUS is a reliable tool for staging liver tumours with a performance similar to that of open IOUS in detecting new nodules.

Usefulness of contrast-enhanced intraoperative ultrasonography (CE-IOUS) in patients with colorectal liver metastases after preoperative chemotherapy

AIMS

The aim of this study was to evaluate the ability of contrast-enhanced intraoperative ultrasonography to detect colorectal liver metastases after preoperative chemotherapy compared with intraoperative ultrasound and preoperative imaging techniques.

METHODS

From January 2010 to December 2011, 28 patients with colorectal liver metastases underwent intraoperative ultrasonography and contrast-enhanced intraoperative ultrasonography during hepatectomy following preoperative chemotherapy. The findings were compared to preoperative imaging using contrast-enhanced ultrasonography, computed tomography, magnetic resonance imaging, and/or fluorodeoxyglucose positron emission tomography.

RESULTS

Preoperative imaging techniques detected 58 metastatic lesions in 28 patients. In 32 % of patients (n = 9), intraoperative ultrasound detected 24 missed hepatic nodules. In 14 % of patients (n = 4), contrast-enhanced intraoperative ultrasonography detected an additional six nodules and change in operative management occurred in 18 % of patients. Using univariate analysis, we found three factors significantly related to detection of additional metastases with contrast-enhanced intraoperative ultrasonography: three or more metastases before chemotherapy (p = 0.047), resolution of at least one metastasis (p = 0.011), and small liver metastases (largest lesion size ≤20 mm) after chemotherapy (p = 0.007).

CONCLUSION

In patients undergoing surgery for colorectal liver metastases after chemotherapy, contrast-enhanced intraoperative ultrasonography improved both the sensitivity of intraoperative ultrasonography to detect liver metastases and the R0 hepatic resection rate.

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.

Gadoxetic acid-enhanced 3.0 T MR imaging versus multidetector-row CT in the detection of colorectal metastases in fatty liver using intraoperative ultrasound and histopathology as a standard of reference

OBJECTIVE

To compare the diagnostic value of gadoxetic acid-enhanced MRI at 3.0 T with 64-row MDCT in the detection of colorectal liver metastases in diffuse fatty infiltration of the liver after neoadjuvant chemotherapy.

METHODS

Twenty-three patients with colorectal liver metastases and at moderate to severe steatosis (25-90%) underwent prospectively preoperative tri-phasic MDCT (Somatom Sensation 64, Siemens) and gadoxetic acid-enhanced MRI (3-T Magnetom Trio, Siemens). All patients underwent surgical resection of liver metastases. Intraoperative ultrasound (IOUS) was carried out, which served as the standard of reference, together with histopathology.

RESULTS

Overall, 68 metastases (range, 0.4-6 cm; 31/68 metastases [46%] ≤ 1 cm) were found at histology. MDCT detected 49/68 lesions (72%), and MRI 66/68 (97%, p < 0.001). For lesions ≤ 1 cm, MDCT detected only 13/31 (41.9%) and MRI 29/31 (93%, p < 0.001). Eight false-positive lesions were detected by MDCT, seven small lesions by MRI. There was no statistically significant difference between the two modalities in the detection of lesions > 1 cm (p = 0.250). IOUS detected all metastases and revealed two false-positive diagnoses.

CONCLUSION

Gadoxetic acid-enhanced 3.0 T MRI is superior to 64-row MDCT in detecting colorectal liver metastases ≤ 1 cm during preoperative staging in patients with liver steatosis. A combination of MRI and IOUS may further improve the outcome of surgical treatment.

Minimally invasive evaluation and treatment of colorectal liver metastases

Minimally invasive techniques used in the evaluation and treatment of colorectal liver metastases (CRLMs) include ultrasonography (US), computed tomography, magnetic resonance imaging, percutaneous and operative ablation therapy, standard laparoscopic techniques, robotic techniques, and experimental techniques of natural orifice endoscopic surgery. Laparoscopic techniques range from simple staging laparoscopy with or without laparoscopic intraoperative US, through intermediate techniques including simple liver resections (LRs), to advanced techniques such as major hepatectomies. Hereins, we review minimally invasive evaluation and treatment of CRLM, focusing on a comparison of open LR (OLR) and minimally invasive LR (MILR). Although there are no randomized trials comparing OLR and MILR, nonrandomized data suggest that MILR compares favorably with OLR regarding morbidity, mortality, LOS, and cost, although significant selection bias exists. The future of MILR will likely include expanding criteria for resectability of CRLM and should include both a patient registry and a formalized process for surgeon training and credentialing.

Robot-assisted laparoscopic ultrasonography for hepatic surgery

INTRODUCTION

This study describes and evaluates a novel, robot-assisted laparoscopic ultrasonographic device for hepatic surgery. Laparoscopic liver surgery is being performed with increasing frequency. One major drawback of this approach is the limited capability of intraoperative ultrasonography (IOUS) using standard laparoscopic devices. Robotic surgery systems offer the opportunity to develop new tools to improve techniques in minimally invasive surgery. This study evaluates a new integrated ultrasonography (US) device with the da Vinci Surgical System for laparoscopic visualization, comparing it with conventional handheld laparoscopic IOUS for performing key tasks in hepatic surgery.

METHODS

A prototype laparoscopic IOUS instrument was developed for the da Vinci Surgical System and compared with a conventional laparoscopic US device in simulation tasks: (1) In vivo porcine hepatic visualization and probe manipulation, (2) lesion detection accuracy, and (3) biopsy precision. Usability was queried by poststudy questionnaire.

RESULTS

The robotic US proved better than conventional laparoscopic US in liver surface exploration (85% success vs 73%; P = .030) and tool manipulation (79% vs 57%; P = .028), whereas no difference was detected in lesion identification (63 vs 58; P = .41) and needle biopsy tasks (57 vs 48; P = .11). Subjects found the robotic US to facilitate better probe positioning (80%), decrease fatigue (90%), and be more useful overall (90%) on the post-task questionnaire.

CONCLUSION

We found this robot-assisted IOUS system to be practical and useful in the performance of important tasks required for hepatic surgery, outperforming free-hand laparoscopic IOUS for certain tasks, and was more subjectively usable to the surgeon. Systems such as this may expand the use of robotic surgery for complex operative procedures requiring IOUS.

Is intra-operative ultrasound still useful for the detection of a hepatic tumour in the era of modern pre-operative imaging?

BACKGROUND

The current role of intra-operative ultrasound (IOUS) is questioned because of recent progress in medical imaging. The aim of the present study was to determine the accuracy of IOUS in the detection of a hepatic tumour (HT) compared with a pre-operative multi-detector computed tomography (MDCT) scan and magnetic resonance imaging (MRI).

METHODS

This retrospective study included 418 patients evaluated using an 8-slice MDCT scan (SCAN8), 64-slice MDCT scan (SCAN64) and MRI alone or combined with a computed tomography (CT) scan. The pathological result was used as a gold standard.

RESULTS

Correlation rates for the number of detected lesions compared with pathology results were 0.627 for SCAN8, 0.785 for SCAN64, 0.657 for MRI and 0.913 for IOUS. Compared with pathology, the rate of concordance was significantly higher with IOUS (0.871) than with SCAN8 (0.736; P=0.011), SCAN64 (0.792; P<0.001) and MRI (0.742; P<0.001). IOUS was responsible for a change in operative strategy in 16.5% of patients. Surgery was extended in 12.4%, limited in 1.7% and abandoned in 2.4%.

CONCLUSIONS

Compared with cross-sectional pre-operative imaging, IOUS is still superior for the detection of HT and the planning of surgery. IOUS remains recommended as a routine procedure in patients having a hepatic resection in the era of modern pre-operative imaging.

Ablative therapies for colorectal liver metastases

Ablative therapies remain a useful adjunct in the multidisciplinary treatment of patients with colorectal liver metastases not amenable to hepatic resection. This review summarizes the rationale, underlying mechanisms, techniques, complications, and outcomes of current and emerging ablative modalities.