Americas Hepato-Pancreato-Biliary Association HPB Ultrasound and Advanced Technology post-graduate course: Overview and review.

Background: Americas Hepato-Pancreato-Biliary Association (AHPBA) established the Hepato-Pancreato-Biliary (HPB) ultrasound (US) and Advanced Technology Post-Graduate Course in 2012 in response to a perceived gap in training and practice. Methods: The HPB US and Advanced Technology Post-Graduate Course consists of both didactic and hands-on skills sessions. The didactic sessions are divided into foundational, organ-focused, and application content. Hands-on sessions are constructed to immediately practice skills in the simulation setting which were taught during the didactic sessions. Course participant demographic data (practice location and practice type) and participant evaluations were reported. Results: Since the first course in 2012, 298 participants have taken the post-graduate course. Most participants reported the content quality, delivery effectiveness, and practice relevance to be either excellent or above average (93.6 %, 91.1 %, 93.6 %, respectively). Participants' motivations to take the course included to enhance skills, knowledge, to incorporate US into practice, or to obtain formal training or qualification/certification, or to teach. Conclusion: The HPB US and Advanced Technology Post-Graduate Course has filled a gap in HPB US training for practicing HPB surgeons. The annual course has been well-received by participants (Kirkpatrick Level 1 Program Evaluation) and will continue to fill the gap in training in operative US for the HPB surgeon. Key message: Americas Hepato-Pancreato-Biliary Association established the HPB Ultrasound and Advanced Technology Post-Graduate Course in 2012. The Course has been well-received by participants and will continue to address a gap in surgical HPB training.

Serum micro-RNA Identifies Early Stage Colorectal Cancer in a Multi-Ethnic Population.

OBJECTIVE: Certain microRNAs (miR) have been previously described to be dysregulated in cancers and can be detected in blood samples. Studies examining the utility of miRs for colon cancer screening have primarily been performed in ethnically homogeneous groups of patients, thus the performance of miRs in multiethnic populations is unknown. METHODS: Four miRs were selected that were shown to be aberrantly expressed in the blood or stool of patients with colorectal cancer (CRC) of various ethnicities. In this study, the ability of these miRs to discern early stage CRC was determined in a previously untested multiethnic population of 73 CRC cases and 18 controls. RESULTS: The ratios of non-vesicular to extracellular vesicular levels of miR's -21, -29a, and -92a were statistically and quantitatively related to CRC stage compared to controls. CONCLUSION: Serum levels of miR-21, miR-29a and miR-92a were able to significantly detect early stage CRC in a multiethnic and previously untested population.
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Segmentation of 3-D High-Frequency Ultrasound Images of Human Lymph Nodes Using Graph Cut With Energy Functional Adapted to Local Intensity Distribution.

Previous studies by our group have shown that 3-D high-frequency quantitative ultrasound (QUS) methods have the potential to differentiate metastatic lymph nodes (LNs) from cancer-free LNs dissected from human cancer patients. To successfully perform these methods inside the LN parenchyma (LNP), an automatic segmentation method is highly desired to exclude the surrounding thin layer of fat from QUS processing and accurately correct for ultrasound attenuation. In high-frequency ultrasound images of LNs, the intensity distribution of LNP and fat varies spatially because of acoustic attenuation and focusing effects. Thus, the intensity contrast between two object regions (e.g., LNP and fat) is also spatially varying. In our previous work, nested graph cut (GC) demonstrated its ability to simultaneously segment LNP, fat, and the outer phosphate-buffered saline bath even when some boundaries are lost because of acoustic attenuation and focusing effects. This paper describes a novel approach called GC with locally adaptive energy to further deal with spatially varying distributions of LNP and fat caused by inhomogeneous acoustic attenuation. The proposed method achieved Dice similarity coefficients of 0.937±0.035 when compared with expert manual segmentation on a representative data set consisting of 115 3-D LN images obtained from colorectal cancer patients.

Reliability and acceptability of six station multiple mini-interviews: past-behavioural versus situational questions in postgraduate medical admission.

BACKGROUND: The multiple mini-interview (MMI) is increasingly used for postgraduate medical admissions and in undergraduate settings. MMIs use mostly Situational Questions (SQs) rather than Past-Behavioural Questions (PBQs). A previous study of MMIs in this setting, where PBQs and SQs were asked in the same order, reported that the reliability of PBQs was non-inferior to SQs and that SQs were more acceptable to candidates. The order in which the questions are asked may affect reliability and acceptability of an MMI. This study investigated the reliability of an MMI using both PBQs and SQs, minimising question order bias. Acceptability of PBQs and SQs was also assessed. METHODS: Forty candidates applying for a postgraduate medical admission for 2016-2017 were included; 24 examiners were used. The MMI consisted of six stations with one examiner per station; a PBQ and a SQ were asked at every station, and the order of questions was alternated between stations. Reliability was analysed for scores obtained for PBQs or SQs separately, and for both questions. A post-MMI survey was used to assess the acceptability of PBQs and SQs. RESULTS: The generalisability (G) coefficients for PBQs only, SQs only, and both questions were 0.87, 0.96, and 0.80, respectively. Decision studies suggested that a four-station MMI would also be sufficiently reliable (G-coefficients 0.82 and 0.94 for PBQs and SQs, respectively). In total, 83% of participants were satisfied with the MMI. In terms of face validity, PBQs were more acceptable than SQs for candidates (p = 0.01), but equally acceptable for examiners (88% vs. 83% positive responses for PBQs vs. SQs; p = 0.377). Candidates preferred PBQs to SQs when asked to choose one, though this difference was not significant (p = 0.081); examiners showed a clear preference for PBQs (p = 0.007). CONCLUSIONS: Reliability and acceptability of six-station MMI were good among 40 postgraduate candidates; modelling suggested that four stations would also be reliable. SQs were more reliable than PBQs. Candidates found PBQs more acceptable than SQs and examiners preferred PBQs when they had to choose between the two. Our findings suggest that it is better to ask both PBQs and SQs during an MMI to maximise acceptability.

Local Transverse-Slice-Based Level-Set Method for Segmentation of 3-D High-Frequency Ultrasonic Backscatter From Dissected Human Lymph Nodes.

OBJECTIVE: To detect metastases in freshly excised human lymph nodes (LNs) using three-dimensional (3-D), high-frequency, quantitative ultrasound (QUS) methods, the LN parenchyma (LNP) must be segmented to preclude QUS analysis of data in regions outside the LNP and to compensate ultrasound attenuation effects due to overlying layers of LNP and residual perinodal fat (PNF). METHODS: After restoring the saturated radio-frequency signals from PNF using an approach based on smoothing cubic splines, the three regions, i.e., LNP, PNF, and normal saline (NS), in the LN envelope data are segmented using a new, automatic, 3-D, three-phase, statistical transverseslice-based level-set (STS-LS) method that amends Lankton's method. Due to ultrasound attenuation and focusing effects, the speckle statistics of the envelope data vary with imaged depth. Thus, to mitigate depth-related inhomogeneity effects, the STS-LS method employs gamma probabilitydensity functions to locally model the speckle statistics within consecutive transverse slices. RESULTS: Accurate results were obtained on simulated data. On a representative dataset of 54 LNs acquired from colorectal-cancer patients, the Dice similarity coefficient for LNP, PNF, and NS were 0.938 ± 0.025, 0.832 ± 0.086, and 0.968 ± 0.008, respectively, when compared to expert manual segmentation. CONCLUSION: The STS-LS outperforms the established methods based on global and local statistics in our datasets and is capable of accurately handling the depth-dependent effects due to attenuation and focusing. SIGNIFICANCE: This advance permits the automatic QUS-based cancer detection in the LNs. Furthermore, the STS-LS method could potentially be used in a wide range of ultrasound-imaging applications suffering from depth-dependent effects.

Past-behavioural versus situational questions in a postgraduate admissions multiple mini-interview: a reliability and acceptability comparison.

BACKGROUND: The Multiple Mini-Interview (MMI) mostly uses 'Situational' Questions (SQs) as an interview format within a station, rather than 'Past-Behavioural' Questions (PBQs), which are most frequently adopted in traditional single-station personal interviews (SSPIs) for non-medical and medical selection. This study investigated reliability and acceptability of the postgraduate admissions MMI with PBQ and SQ interview formats within MMI stations. METHODS: Twenty-six Japanese medical graduates, first completed the two-year national obligatory initial postgraduate clinical training programme and then applied to three specialty training programmes - internal medicine, general surgery, and emergency medicine - in a Japanese teaching hospital, where they underwent the Accreditation Council for Graduate Medical Education (ACGME)-competency-based MMI. This MMI contained five stations, with two examiners per station. In each station, a PBQ, and then an SQ were asked consecutively. PBQ and SQ interview formats were not separated into two different stations, or the order of questioning of PBQs and SQs in individual stations was not changed due to lack of space and experienced examiners. Reliability was analysed for the scores of these two MMI question types. Candidates and examiners were surveyed on this experience. RESULTS: The PBQ and SQ formats had generalisability coefficients of 0.822 and 0.821, respectively. With one examiner per station, seven stations could produce a reliability of more than 0.80 in both PBQ and SQ formats. More than 60% of both candidates and examiners felt positive about the overall candidates' ability. All participants liked the fairness of this MMI when compared with the previously experienced SSPI. SQs were perceived more favourable by candidates; in contrast, PBQs were perceived more relevant by examiners. CONCLUSIONS: Both PBQs and SQs are equally reliable and acceptable as station interview formats in the postgraduate admissions MMI. However, the use of the two formats within the same station, and with a fixed order, is not the best to maximise its utility as an admission test. Future studies are required to evaluate how best the SQs and PBQs should be combined as station interview formats to enhance reliability, feasibility, acceptability and predictive validity of the MMI.

Modeling the envelope statistics of three-dimensional high-frequency ultrasound echo signals from dissected human lymph nodes.

This work investigates the statistics of the envelope of three-dimensional (3D) high-frequency ultrasound (HFU) data acquired from dissected human lymph nodes (LNs). Nine distributions were employed, and their parameters were estimated using the method of moments. The Kolmogorov Smirnov (KS) metric was used to quantitatively compare the fit of each candidate distribution to the experimental envelope distribution. The study indicates that the generalized gamma distribution best models the statistics of the envelope data of the three media encountered: LN parenchyma, fat and phosphate-buffered saline (PBS). Furthermore, the envelope statistics of the LN parenchyma satisfy the pre-Rayleigh condition. In terms of high fitting accuracy and computationally efficient parameter estimation, the gamma distribution is the best choice to model the envelope statistics of LN parenchyma, while, the Weibull distribution is the best choice to model the envelope statistics of fat and PBS. These results will contribute to the development of more-accurate and automatic 3D segmentation of LNs for ultrasonic detection of clinically significant LN metastases.

Intestinal anisakiasis as a rare cause of small bowel obstruction.

Anisakiasis, a parasitic infection by larvae of the nematode Anisakis found in raw or undercooked saltwater fish, mostly involves stomach but rarely small intestine. We report a rare case of a 61-year-old man who presented with abdominal pain and developed small bowel obstruction caused by intestinal anisakiasis. Abdominal computed tomography revealed segmental edema of the intestinal wall with proximal dilatation. The patient underwent urgent laparotomy because strangulated small bowel obstruction was suspected. A localized portion of the intestine around jejunoileal junction was found to be erythematous, edematous, and hardened, which was resected. The resected specimen showed a linear whitish worm, Anisakis simplex, penetrating into the intestinal mucosa. It is often clinically challenging to consider intestinal anisakiasis in the differential diagnosis because of its nonspecific abdominal symptoms and findings. Although gastrointestinal anisakiasis is still rare in the United States, the incidence is expected to rise given the growing popularity of Japanese cuisine such as sushi or sashimi. Anisakiasis should be considered as one of the differential diagnoses in patients with nonspecific abdominal symptoms after consumption of raw or undercooked fish.

Three-dimensional quantitative ultrasound for detecting lymph node metastases.

PURPOSE: Detection of metastases in lymph nodes (LNs) is critical for cancer management. Conventional histological methods may miss metastatic foci. To date, no practical means of evaluating the entire LN volume exists. The aim of this study was to develop fast, reliable, operator-independent, high-frequency, quantitative ultrasound (QUS) methods for evaluating LNs over their entire volume to effectively detect LN metastases. METHODS: We scanned freshly excised LNs at 26 MHz and digitally acquired echo-signal data over the entire three-dimensional (3D) volume. A total of 146 LNs of colorectal, 26 LNs of gastric, and 118 LNs of breast cancer patients were enrolled. We step-sectioned LNs at 50-µm intervals and later compared them with 13 QUS estimates associated with tissue microstructure. Linear-discriminant analysis classified LNs as metastatic or nonmetastatic, and we computed areas (Az) under receiver-operator characteristic curves to assess classification performance. The QUS estimates and cancer probability values derived from discriminant analysis were depicted in 3D images for comparison with 3D histology. RESULTS: Of 146 LNs of colorectal cancer patients, 23 were metastatic; Az = 0.952 ± 0.021 (95% confidence interval [CI]: 0.911-0.993); sensitivity = 91.3% (specificity = 87.0%); and sensitivity = 100% (specificity = 67.5%). Of 26 LNs of gastric cancer patients, five were metastatic; Az = 0.962 ± 0.039 (95% CI: 0.807-1.000); sensitivity = 100% (specificity = 95.3%). A total of 17 of 118 LNs of breast cancer patients were metastatic; Az = 0.833 ± 0.047 (95% CI: 0.741-0.926); sensitivity = 88.2% (specificity = 62.5%); sensitivity = 100% (specificity = 50.5%). 3D cancer probability images showed good correlation with 3D histology. CONCLUSIONS: These results suggest that operator- and system-independent QUS methods allow reliable entire-volume LN evaluation for detecting metastases. 3D cancer probability images can help pathologists identify metastatic foci that could be missed using conventional methods.

Internal hernia due to mesenteric defect.

Internal hernia is one of the rare causes of small bowel obstruction. A congenital mesenteric defect is very rare, but can potentially cause internal hernia with consequent incarceration or strangulation of the small intestine. An 18-year-old woman was brought to our emergency department with sudden onset lower abdominal pain. She had no remarkable past medical history and took no medications. An emergency laparotomy was performed. On exploring the abdominal cavity, the mesenteric defect was detected in the jejunal region, 3 cm in size. Loops of small intestine had gone through the defect three times in a complex manner and strangulated. Gangrenous intestine was resected and a primary anastomosis was performed. An adult congenital mesenteric defect is rare; however, it should be considered as one of the differential diagnoses in a relatively young patient with bowel obstruction without external hernia, previous abdominal surgery or trauma.

Three-dimensional quantitative ultrasound to guide pathologists towards metastatic foci in lymph nodes.

The detection of metastases in freshly-excised lymph nodes from cancer patients during lymphadenectomy is critically important for cancer staging, treatment, and optimal patient management. Currently, conventional histologic methods suffer a high rate of false-negative determinations because pathologists cannot evaluate each excised lymph nodes in its entirety. Therefore, lymph nodes are undersampled and and small but clinically relevant metastatic regions can be missed. In this study, quantitative ultrasound (QUS) methods using high-frequency transducers (i.e., > 20 MHz) were developed and evaluated for their ability to detect and guide pathologists towards suspicious regions in lymph nodes. A custom laboratory scanning system was used to acquire radio-frequency (RF) data in 3D from excised lymph nodes using a 26-MHz center-frequency transducer. Overlapping 1-mm cylindrical regions-of-interest (ROIs) of the RF data were processed to yield 13 QUS estimates quantifying tissue microstructure and organization. These QUS methods were applied to more than 260 nodes from more than 160 colorectal-, gastric-, and breast-cancer patients. Cancer-detection performance was assessed for individual estimates and linear combinations of estimates. ROC results demonstrated excellent classification. For colorectal- and gastric-cancer nodes, the areas under the ROC curves (AUCs) were greater than 0.95. Slightly poorer results (AUC=0.85) were obtained for breast-cancer nodes. Images based on QUS parameters also permitted localization of cancer foci in some micrometastatic cases.

Entire-volume serial histological examination for detection of micrometastases in lymph nodes of colorectal cancers.

The purpose of this study was to accurately detect lymph-node micrometastases, i.e., metastatic cancer foci that have a size between 2.0 and 0.2 mm, in nodes excised from colorectal cancer (CRC) patients, and to determine how frequently micrometastases might be missed when standard histological examination procedures are used. A total of 311 lymph nodes were removed and examined from 90 patients with Stage I to IV CRC. The number of slices of histology sections ranged from 6 to 75 per node (average = 25.5; SD = 11.1), which provided a total of 7,943 slices. Lymph nodes were examined in their entire volume at every 50-µm and 100-µm intervals for nodes smaller and larger than 5 mm respectively. The total number of thin sections examined in each node and the number of thin sections where metastatic foci were present were counted. The number of thin sections with metastatic foci and the total number of slices was determined for each node. In addition, the presence or absence of metastatic foci in the "central" slice was determined. Micrometastases were found in 12/311 (3.9%) of all lymph nodes. In the 12 lymph nodes with micrometastases, the rate of metastatic slices over all slices was 39.4% (range = 6.3 to 81.3%; SD = 25.8%) In the central slice of each node, micrometastases were present only in 6 of 12 lymph nodes (50%); accordingly, they were not present in the central slice for half the micrometastatic nodes. These 6 nodes represented 1.9% of the 311 nodes and 11.1% of the 54 metastatic nodes. This study suggests that a significant fraction of micrometastases can be missed by traditional singleslice sectioning; half of the micrometastases would have been overlooked in our data set of 311 nodes.

Quantitative ultrasound in cancer imaging.

Ultrasound is a relatively inexpensive, portable, and versatile imaging modality that has a broad range of clinical uses. It incorporates many imaging modes, such as conventional gray-scale "B-mode" imaging to display echo amplitude in a scanned plane; M-mode imaging to track motion at a given fixed location over time; duplex, color, and power Doppler imaging to display motion in a scanned plane; harmonic imaging to display nonlinear responses to incident ultrasound; elastographic imaging to display relative tissue stiffness; and contrast-agent imaging with simple contrast agents to display blood-filled spaces or with targeted agents to display specific agent-binding tissue types. These imaging modes have been well described in the scientific, engineering, and clinical literature. A less well-known ultrasonic imaging technology is based on quantitative ultrasound (QUS), which analyzes the distribution of power as a function of frequency in the original received echo signals from tissue and exploits the resulting spectral parameters to characterize and distinguish among tissues. This article discusses the attributes of QUS-based methods for imaging cancers and providing improved means of detecting and assessing tumors. The discussion will include applications to imaging primary prostate cancer and metastatic cancer in lymph nodes to illustrate the methods.

Three-dimensional high-frequency backscatter and envelope quantification of cancerous human lymph nodes.

Quantitative imaging methods using high-frequency ultrasound (HFU) offer a means of characterizing biological tissue at the microscopic level. Previously, high-frequency, 3-D quantitative ultrasound (QUS) methods were developed to characterize 46 freshly-dissected lymph nodes of colorectal-cancer patients. 3-D ultrasound radiofrequency data were acquired using a 25.6 MHz center-frequency transducer and each node was inked before tissue fixation to recover orientation after sectioning for 3-D histological evaluation. Backscattered echo signals were processed using 3-D cylindrical regions-of-interest (ROIs) to yield four QUS estimates associated with tissue microstructure (i.e., effective scatterer size, acoustic concentration, intercept and slope). These QUS estimates, obtained by parameterizing the backscatter spectrum, showed great potential for cancer detection. In the present study, these QUS methods were applied to 112 lymph nodes from 77 colorectal and gastric cancer patients. Novel QUS methods parameterizing the envelope statistics of the ROIs using Nakagami and homodyned-K distributions were also developed; they yielded four additional QUS estimates. The ability of these eight QUS estimates to classify lymph nodes and detect cancer was evaluated using receiver operating characteristics (ROC) curves. An area under the ROC curve of 0.996 with specificity and sensitivity of 95% were obtained by combining effective scatterer size and one envelope parameter based on the homodyned-K distribution. Therefore, these advanced 3-D QUS methods potentially can be valuable for detecting small metastatic foci in dissected lymph nodes.

Improvement of long-term survival of colorectal cancer in Japanese-Americans of Hawaii from 1990 to 2001.

BACKGROUND: To compare the long-term survival of colorectal cancer (CRC) during two 6-year periods using patients with similar characteristics of the same ethnicity in Hawaii. METHODS: A retrospective review of Japanese-American patients in Hawaii with CRC surgically resected and followed more than 5 years in a single institution. Patients were divided into two groups by date that patients had surgery: Group 1; 1990-1995, and Group 2; 1996-2001 (introduction of newer chemotherapy, aggressive surgery for liver metastases including radiofrequency thermal ablation). RESULTS: A total of 344 patients in Group 1 (median age 69.5 years) and 330 patients in Group 2 (median age 71.7 years) were included. There were no differences between two groups in gender, age, anatomic site, carcinoembryonic antigen, tumor size, histologic grade, and TNM stage distribution, including pT, pN, and pM status. Overall 5-year survival rate difference approached significance between two groups (Group 1: 73.2% vs. Group 2: 78.9%; p = 0.097). Particularly, there was significant difference in stage IV patients (Group 1; 8.7% vs. Group 2: 26.0%; p = 0.030) and histologic grade 3 (Group 1; 41.67% vs. Group 2: 67.73%; p = 0.032). Subgroup analyses showed significant difference (p < 0.05) for more advanced cancers (larger tumor, node positive, metastatic disease, poorly differentiated cancer). CONCLUSIONS: In this study of patients with the same ethnicity, the better survival outcome in latter (Group 2) patients suggests improvement of treatment, especially for patients with more advanced and metastatic cancer (stage IV).

Three-dimensional high-frequency characterization of cancerous lymph nodes.

High-frequency ultrasound (HFU) offers a means of investigating biologic tissue at the microscopic level. High-frequency, three-dimensional (3-D) quantitative-ultrasound (QUS) methods were developed to characterize freshly-dissected lymph nodes of cancer patients. Three-dimensional ultrasound data were acquired from lymph nodes using a 25.6-MHz center-frequency transducer. Each node was inked prior to tissue fixation to recover orientation after sectioning for 3-D histologic evaluation. Backscattered echo signals were processed using 3-D cylindrical regions-of-interest to yield four QUS estimates associated with tissue microstructure (i.e., effective scatterer size, acoustic concentration, intercept and slope). QUS estimates were computed following established methods using two scattering models. In this study, 46 lymph nodes acquired from 27 patients diagnosed with colon cancer were processed. Results revealed that fully-metastatic nodes could be perfectly differentiated from cancer-free nodes using slope or scatterer-size estimates. Specifically, results indicated that metastatic nodes had an average effective scatterer size (i.e., 37.1 +/- 1.7 microm) significantly larger (p < 0.05) than that in cancer-free nodes (i.e., 26 +/- 3.3 microm). Therefore, the 3-D QUS methods could provide a useful means of identifying small metastatic foci in dissected lymph nodes that might not be detectable using current standard pathology procedures.

The routine use of laparoscopic ultrasound decreases bile duct injury: a multicenter study.

OBJECTIVE: Laparoscopic ultrasound (LUS) has been used for over 15 years to screen the bile duct (BD) for stones and to delineate anatomy during laparoscopic cholecystectomy (LC). LUS as a modality to prevent BD injury has not been investigated in a large series. This study evaluated the routine use of LUS to determine its effect on preventing BD injury. METHODS: A multicenter retrospective study was performed by reviewing clinical outcome of LC in which LUS was used routinely. RESULTS: In five centers, 1,381 patients underwent LC with LUS. LUS was successful to delineate and evaluate the BD in 1,352 patients (98.0%), although it was unsuccessful or incomplete in 29 patients (2.0%). LUS was considered remarkably valuable to safely complete LC, avoiding conversion to open, in 81 patients (5.9%). The use of intraoperative cholangiography (IOC) varied depending on centers; IOC was performed in 504 patients (36.5%). For screening of BD stones (which was positive in 151 patients, 10.9%), LUS had a false-positive result in two patients (0.1%) and a false-negative result in five patients (0.4%). There were retained BD stones in three patients (0.2%). There were minor bile leaks from the liver bed in three patients (0.2%). However, there were no other BD injuries including BD transection (0%). Retrospectively, IOC was deemed necessary in 25 patients (1.8%) to complete LC in spite of routine LUS. CONCLUSION: LUS can be performed successfully to delineate BD anatomy in the majority of patients. The routine use of LUS during LC has obviated major BD injury, compared to the reported rate (1 out of 200-400 LCs). LUS improves the safety of LC by clarifying anatomy and decreasing BD injury.

A multicentre controlled study of the InLine radiofrequency ablation device for liver transection.

BACKGROUND: Surgical resection is the most effective therapy for liver cancer. Intraoperative blood loss during liver resection remains a major concern due to association with higher postoperative complications. The InLine radiofrequency ablation device (ILRFA) has achieved promising results in liver surgery with minimal blood loss and no increase of postoperative complications. In this multicentre controlled study, 108 patients undergoing liver resection were investigated. PATIENTS AND METHODS: A total of 108 patients underwent liver resections in 4 medical centres; the prospective sequential cohort study consisted of 54 ILRFA and 54 ultrasonic surgical aspirator transections as the control group. RESULTS: The type of liver resection performed was very similar in both groups. The median number of RFA deployments was 3 (range 1-12) with a median coagulation time of 9 (range 3-36) min. Median blood loss was 165+/-20 ml (range 5-675) in the ILRFA and 654+/-83 ml (range 80-3600) in the control group (p<0.001). The median transection time was 27 (2-219) min in the ILRFA group and 35 (5-62) min in controls. CONCLUSIONS: Our study indicates that ILRFA device for liver transection is effective in reducing blood loss and is safe. Precoagulation before parenchymal transection appears to be a valid concept in liver surgery. The avoidance of vascular inflow occlusion during parenchymal transection could also be of value.