Optimization of anastomotic technique and gastric conduit perfusion with hyperspectral imaging and machine learning in an experimental model for minimally invasive esophagectomy.

INTRODUCTION: Esophagectomy is the mainstay of esophageal cancer treatment, but anastomotic insufficiency related morbidity and mortality remain challenging for patient outcome. Therefore, the objective of this work was to optimize anastomotic technique and gastric conduit perfusion with hyperspectral imaging (HSI) for total minimally invasive esophagectomy (MIE) with linear stapled anastomosis. MATERIAL AND METHODS: A live porcine model (n = 58) for MIE was used with gastric conduit formation and simulation of linear stapled side-to-side esophagogastrostomy. Four main experimental groups differed in stapling length (3 vs. 6 cm) and simulation of anastomotic position on the conduit (cranial vs. caudal). Tissue oxygenation around the anastomotic simulation site was evaluated using HSI and was validated with histopathology. RESULTS: The tissue oxygenation (ΔStO2) after the anastomotic simulation remained constant only for the short stapler in caudal position (-0.4 ± 4.4%, n.s.) while it was impaired markedly in the other groups (short-cranial: -15.6 ± 11.5%, p = 0.0002; long-cranial: -20.4 ± 7.6%, p = 0.0126; long-caudal: -16.1 ± 9.4%, p < 0.0001). Tissue samples from avascular stomach as measured by HSI showed correspondent eosinophilic pre-necrotic changes in 35.7 ± 9.7% of the surface area. CONCLUSION: Tissue oxygenation at the site of anastomotic simulation of the gastric conduit during MIE is influenced by stapling technique. Optimal oxygenation was achieved with a short stapler (3 cm) and sufficient distance of the simulated anastomosis to the cranial end of the gastric conduit. HSI tissue deoxygenation corresponded to histopathologic necrotic tissue changes. The experimental model with HSI and ML allow for systematic optimization of gastric conduit perfusion and anastomotic technique while clinical translation will have to be proven.

Telestration with augmented reality for visual presentation of intraoperative target structures in minimally invasive surgery: a randomized controlled study.

AIMS: In minimally invasive surgery (MIS), intraoperative guidance has been limited to verbal communication without direct visual guidance. Communication issues and mistaken instructions in training procedures can hinder correct identification of anatomical structures on the MIS screen. The iSurgeon system was developed to provide visual guidance in the operating room by telestration with augmented reality (AR). METHODS: Laparoscopic novices (n = 60) were randomized in two groups in a cross-over design: group 1 trained only with verbal guidance first and then with additional telestration with AR on the operative screen and vice versa for group 2. Training consisted of laparoscopic basic training and subsequently a specifically designed training course, including a porcine laparoscopic cholecystectomy (LC). Outcome included time needed for training, performance with Global Operative Assessment of Laparoscopic Skills (GOALS), and Objective Structured Assessment of Technical Skills (OSATS) score for LC, complications, and subjective workload (NASA-TLX questionnaire). RESULTS: Telestration with AR led to significantly faster total training time (1163 ± 275 vs. 1658 ± 375 s, p < 0.001) and reduced error rates. LC on a porcine liver was performed significantly better (GOALS 21 ± 5 vs. 18 ± 4, p < 0.007 and OSATS 67 ± 11 vs. 61 ± 8, p < 0.015) and with less complications (13.3% vs. 40%, p < 0.020) with AR. Subjective workload and stress were significantly reduced during training with AR (33.6 ± 12.0 vs. 30.6 ± 12.9, p < 0.022). CONCLUSION: Telestration with AR improves training success and safety in MIS. The next step will be the clinical application of telestration with AR and the development of a mobile version for remote guidance.

Randomized controlled trial of robotic-assisted versus conventional laparoscopic fundoplication: 12 years follow-up.

AIMS: Numerous reports have addressed the feasibility and safety of robotic-assisted (RALF) and conventional laparoscopic fundoplication (CLF). Long-term follow-up after direct comparison of these two minimally invasive approaches is scarce. The aim of the present study was to assess long-term disease-specific symptoms and quality of life (QOL) in patients with gastroesophageal reflux disease (GERD) treated with RALF or CLF after 12 years in the randomized ROLAF trial. METHODS: In the ROLAF trial 40 patients with GERD were randomized to RALF (n = 20) or CLF (n = 20) between August 2004 and December 2005. At 12 years after surgery, all patients were invited to complete the standardized Gastrointestinal Symptom Rating Scale (GSRS) and the Quality of Life in Reflux and Dyspepsia questionnaire (QOLRAD). Failure of treatment was assessed according to Lundell score. RESULTS: The GSRS score was similar for RALF (n = 15) and CLF (n = 15) at 12 years´ follow-up (2.1 ± 0.7 vs. 2.2 ± 1.3, p = 0.740). There was no difference in QOLRAD score (RALF 6.4 ± 1.2; CLF 6.4 ± 1.5, p = 0.656) and the QOLRAD score sub items. Long-term failure of treatment according to the definition by Lundell was not different between RALF and CLF [46% (6/13) vs. 33% (4/12), p = 0.806]. CONCLUSION: In accordance with previous short-term outcome studies, the long-term results 12 years after surgery showed no difference between RALF and CLF regarding postoperative symptoms, QOL and failure of treatment. Relief of symptoms and patient satisfaction were high after both procedures on the long-term. REGISTRATION NUMBER: DRKS00014690 ( https://www.drks.de ).

[Microvascular changes in COVID-19]. / Mikrovaskuläre Veränderungen bei COVID-19.

BACKGROUND: Clinically, coronavirus disease 2019 (COVID-19) is associated with a wide range of symptoms, which can range from mild complaints of an upper respiratory infection to life-threatening hypoxic respiratory insufficiency and multiorgan failure. OBJECTIVE: The initially identified pulmonary damage patterns, such as diffuse alveolar damage in acute lung failure, are accompanied by new findings that draw a more complex scenario. These include microvascular involvement and a wide range of associated pathologies of multiple organ systems. A back-scaling of microstructural vascular changes is possible via targeted correlation of pathological autopsy results with radiological imaging. MATERIAL AND METHODS: Radiological and pathological correlation as well as microradiological imaging to investigate microvascular involvement in fatal COVID-19. RESULTS: The cases of two COVID-19 patients are presented. Patient 1 showed a relative hypoperfusion in lung regions that did not have typical COVID-19 infiltrates; the targeted post-mortem correlation also showed subtle signs of microvascular damage even in these lung sections. Patient 2 showed both radiologically and pathologically advanced typical COVID-19 destruction of lung structures and the case illustrates the damage patterns of the blood-air barrier. The perfusion deficit of the intestinal wall shown in computed tomography of patient 2 could not ultimately clearly be microscopically attributed to intestinal microvascular damage. CONCLUSION: In addition to microvascular thrombosis, our results indicate a functional pulmonary vasodysregulation as part of the pathophysiology during the vascular phase of COVID-19. The clinical relevance of autopsies and the integration of radiological imaging findings into histopathological injury patterns must be emphasized for a better understanding of COVID-19.

LapTrain: multi-modality training curriculum for laparoscopic cholecystectomy-results of a randomized controlled trial.

BACKGROUND: Multiple training modalities for laparoscopy have different advantages, but little research has been conducted on the benefit of a training program that includes multiple different training methods compared to one method only. This study aimed to evaluate benefits of a combined multi-modality training program for surgical residents. METHODS: Laparoscopic cholecystectomy (LC) was performed on a porcine liver as the pre-test. Randomization was stratified for experience to the multi-modality Training group (12 h of training on Virtual Reality (VR) and box trainer) or Control group (no training). The post-test consisted of a VR LC and porcine LC. Performance was rated with the Global Operative Assessment of Laparoscopic Skills (GOALS) score by blinded experts. RESULTS: Training (n = 33) and Control (n = 31) were similar in the pre-test (GOALS: 13.7 ± 3.4 vs. 14.7 ± 2.6; p = 0.198; operation time 57.0 ± 18.1 vs. 63.4 ± 17.5 min; p = 0.191). In the post-test porcine LC, Training had improved GOALS scores (+ 2.84 ± 2.85 points, p < 0.001), while Control did not (+ 0.55 ± 2.34 points, p = 0.154). Operation time in the post-test was shorter for Training vs. Control (40.0 ± 17.0 vs. 55.0 ± 22.2 min; p = 0.012). Junior residents improved GOALS scores to the level of senior residents (pre-test: 13.7 ± 2.7 vs. 18.3 ± 2.9; p = 0.010; post-test: 15.5 ± 3.4 vs. 18.8 ± 3.8; p = 0.120) but senior residents remained faster (50.1 ± 20.6 vs. 25.0 ± 1.9 min; p < 0.001). No differences were found between groups on the post-test VR trainer. CONCLUSIONS: Structured multi-modality training is beneficial for novices to improve basics and overcome the initial learning curve in laparoscopy as well as to decrease operation time for LCs in different stages of experience. Future studies should evaluate multi-modality training in comparison with single modalities. TRIAL REGISTRATION: German Clinical Trials Register DRKS00011040.

[The way from cost approval to bariatric surgery : Analysis of resource utilization in a maximum care hospital]. / Vom Antrag auf Kostengutsprache bis zur bariatrischen Operation : Personelle Ressourcenanalyse an einem Zentrum der Maximalversorgung.

BACKGROUND: Morbid obesity is a medical and economic challenge. Patients who have the indications for bariatric surgery face a long way from the first visit until surgery and a high utilization of resources is required. OBJECTIVES: The present study aimed to evaluate labor costs and labor time required to supervise obese patients from their first visit until preparation of a bariatric report to ask for cost acceptance of bariatric surgery from their health insurance. In addition, the reasons for not receiving bariatric surgery after receiving cost acceptance from the health insurance were evaluated. MATERIAL AND METHODS: Patients who had indications for bariatric surgery according to the S3 guidelines between 2012 and 2013, were evaluated regarding labor costs and labor time of the process from the first visit until receiving cost acceptance from their health insurance. Furthermore, body mass index (BMI), age, sex, Edmonton Obesity Staging System (EOSS) stage and comorbidities were evaluated. Patients who had not received surgery up to December 2015 were contacted via telephone to ask for the reasons. RESULTS: In the present study 176 patients were evaluated (110 females, 62.5%). Until preparation of a bariatric report the patients required an average of 2.7 combined visits in the department of surgery with the department of nutrition, 1.7 visits in the department of psychosomatic medicine, 1.5 separate visits in the department of nutrition and 1.4 visits in the department of internal medicine. Average labor costs from the first visit until the bariatric survey were 404.90 ± 117.00 euros and 130 out of 176 bariatric reports were accepted by the health insurance (73.8%). For another 40 patients a second bariatric survey was made and 20 of these (50%) were accepted, which results in a total acceptance rate of 85.2% (150 out of 176). After a mean follow-up of 2.8 ± 1.1 years only 93 out of 176 patients had received bariatric surgery (53.8%). Of these 16 had received acceptance of surgery by their health insurance only after a second bariatric survey. CONCLUSION: A large amount of labor and financial resources are required for treatment of obese patients from first presentation up to bariatric surgery. The cost-benefit calculation of an obesity center needs to include that approximately one half of the patients do not receive surgery within more than 2.5 years.

[Intelligent operating room suite : From passive medical devices to the self-thinking cognitive surgical assistant]. / Der intelligente Operationssaal : Vom passiven Gerätepark zum mitdenkenden, kognitiven Assistenten.

Modern operating room (OR) suites are mostly digitally connected but until now the primary focus was on the presentation, transfer and distribution of images. Device information and processes within the operating theaters are barely considered. Cognitive assistance systems have triggered a fundamental rethinking in the automotive industry as well as in logistics. In principle, tasks in the OR, some of which are highly repetitive, also have great potential to be supported by automated cognitive assistance via a self-thinking system. This includes the coordination of the entire workflow in the perioperative process in both the operating theater and the whole hospital. With corresponding data from hospital information systems, medical devices and appropriate models of the surgical process, intelligent systems could optimize the workflow in the operating theater in the near future and support the surgeon. Preliminary results on the use of device information and automatically controlled OR suites are already available. Such systems include, for example the guidance of laparoscopic camera systems. Nevertheless, cognitive assistance systems that make use of knowledge about patients, processes and other pieces of information to improve surgical treatment are not yet available in the clinical routine but are urgently needed in order to automatically assist the surgeon in situation-related activities and thus substantially improve patient care.

Electromagnetic organ tracking allows for real-time compensation of tissue shift in image-guided laparoscopic rectal surgery: results of a phantom study.

BACKGROUND: Laparoscopic resection is a minimally invasive treatment option for rectal cancer but requires highly experienced surgeons. Computer-aided technologies could help to improve safety and efficiency by visualizing risk structures during the procedure. The prerequisite for such an image guidance system is reliable intraoperative information on iatrogenic tissue shift. This could be achieved by intraoperative imaging, which is rarely available. Thus, the aim of the present study was to develop and validate a method for real-time deformation compensation using preoperative imaging and intraoperative electromagnetic tracking (EMT) of the rectum. METHODS: Three models were compared and evaluated for the compensation of tissue deformation. For model A, no compensation was performed. Model B moved the corresponding points rigidly to the motion of the EMT sensor. Model C used five nested linear regressions with increasing level of complexity to compute the deformation (C1-C5). For evaluation, 14 targets and an EMT organ sensor were fit into a silicone-molded rectum of the OpenHELP phantom. Following a computed tomography, the image guidance was initiated and the rectum was deformed in the same way as during surgery in a total of 14 experimental runs. The target registration error (TRE) was measured for all targets in different positions of the rectum. RESULTS: The mean TRE without correction (model A) was 32.8 ± 20.8 mm, with only 19.6% of the measurements below 10 mm (80.4% above 10 mm). With correction, the mean TRE could be reduced using the rigid correction (model B) to 6.8 ± 4.8 mm with 78.7% of the measurements being <10 mm. Using the most complex linear regression correction (model C5), the error could be reduced to 2.9 ± 1.4 mm with 99.8% being below 10 mm. CONCLUSION: In laparoscopic rectal surgery, the combination of electromagnetic organ tracking and preoperative imaging is a promising approach to compensating for intraoperative tissue shift in real-time.

Computer-assisted abdominal surgery: new technologies.

BACKGROUND: Computer-assisted surgery is a wide field of technologies with the potential to enable the surgeon to improve efficiency and efficacy of diagnosis, treatment, and clinical management. PURPOSE: This review provides an overview of the most important new technologies and their applications. METHODS: A MEDLINE database search was performed revealing a total of 1702 references. All references were considered for information on six main topics, namely image guidance and navigation, robot-assisted surgery, human-machine interface, surgical processes and clinical pathways, computer-assisted surgical training, and clinical decision support. Further references were obtained through cross-referencing the bibliography cited in each work. Based on their respective field of expertise, the authors chose 64 publications relevant for the purpose of this review. CONCLUSION: Computer-assisted systems are increasingly used not only in experimental studies but also in clinical studies. Although computer-assisted abdominal surgery is still in its infancy, the number of studies is constantly increasing, and clinical studies start showing the benefits of computers used not only as tools of documentation and accounting but also for directly assisting surgeons during diagnosis and treatment of patients. Further developments in the field of clinical decision support even have the potential of causing a paradigm shift in how patients are diagnosed and treated.

OpenHELP (Heidelberg laparoscopy phantom): development of an open-source surgical evaluation and training tool.

BACKGROUND: Apart from animal testing and clinical trials, surgical research and laparoscopic training mainly rely on phantoms. The aim of this project was to design a phantom with realistic anatomy and haptic characteristics, modular design and easy reproducibility. The phantom was named open-source Heidelberg laparoscopic phantom (OpenHELP) and serves as an open-source platform. METHODS: The phantom was based on an anonymized CT scan of a male patient. The anatomical structures were segmented to obtain digital three-dimensional models of the torso and the organs. The digital models were materialized via rapid prototyping. One flexible, using an elastic abdominal wall, and one rigid method, using a plastic shell, to simulate pneumoperitoneum were developed. Artificial organ production was carried out sequentially starting from raw gypsum models to silicone molds to final silicone casts. The reproduction accuracy was exemplarily evaluated for ten silicone rectum models by comparing the digital 3D surface of the original rectum with CT scan by calculating the root mean square error of surface variations. Haptic realism was also evaluated to find the most realistic silicone compositions on a visual analog scale (VAS, 0-10). RESULTS: The rigid and durable plastic torso and soft silicone organs of the abdominal cavity were successfully produced. A simulation of pneumoperitoneum could be created successfully by both methods. The reproduction accuracy of ten silicone rectum models showed an average root mean square error of 2.26 (0-11.48) mm. Haptic realism revealed an average value on a VAS of 7.25 (5.2-9.6) for the most realistic rectum. CONCLUSION: The OpenHELP phantom proved to be feasible and accurate. The phantom was consecutively applied frequently in the field of computer-assisted surgery at our institutions and is accessible as an open-source project at www.open-cas.org for the academic community.

Polypropylene, polyester or polytetrafluoroethylene-is there an ideal material for mesh augmentation at the esophageal hiatus? Results from an experimental study in a porcine model.

PURPOSE: Knowledge about the influence of underlying biomaterial on behavior of surgical meshes at the esophageal hiatus is rare, but essential for safe and effective hiatal hernia surgery. This study aimed to characterize the influence of polymer material on mesh behavior at the hiatus. METHODS: 24 pigs in three groups of eight underwent implantation of either polypropylene (PP), polyester (PET) or polytetrafluoroethylene (PTFE) mesh placed circularly at the esophageal hiatus. After 8 weeks, necropsy and measurements were performed evaluating mesh deformation, adhesion formation, fixation of the esophagogastric junction and mesh position. Foreign body reaction was assessed by mononuclear cell count and immunostaining of Ki-67. Tissue integration was evaluated by immunostaining of type I and type III collagen fibers. RESULTS: Mesh shrinkage was the highest for PTFE, lower for PP and the lowest for PET (34.9 vs. 19.8 vs. 12.1 %; p = 0.002). Mesh aperture for the esophagus showed an enlargement within all groups, which was highest for PTFE compared to PP and PET (100.8 vs. 47.0 vs. 35.9 %; p = 0.001). The adhesion score was highest for PP, lower for PTFE and the lowest for PET (11.0 vs. 9.5 vs. 5.0; p = 0.001) and correlated positively with the score of esophagogastric fixation (r s = 0.784, p < 0.001). No mesh migration, erosion or stenosis of the esophagus occurred. Evaluation of foreign body reaction and tissue integration showed no significant differences. CONCLUSIONS: In this experimental setting, PP-meshes showed the most appropriate characteristics for augmentation at the hiatus. Due to solid fixation of the esophagogastric junction and low shrinkage tendency, PP-meshes may be effective in preventing hiatal hernia recurrence. The use of PTFE-mesh at the hiatus may be disadvantageous due to high shrinkage rates and correlating enlargement of the aperture for the esophagus.

Magnetic tracking in the operation room using the da Vinci(®) telemanipulator is feasible.

In recent years, robotic assistance for surgical procedures has grown on a worldwide scale, particularly for use in more complex operations. Such operations usually require meticulous handling of tissue, involve a narrow working space and limit the surgeon's sense of orientation in the human body. Improvement in both tissue handling and working within a narrow working space might be achieved through the use of robotic assistance. Soft tissue navigation might improve orientation by visualizing important target and risk structures intraoperatively, thereby possibly improving patient outcome. Prerequisites for navigation are its integration into the surgical workflow and accurate localization of both the instruments and patient. Magnetic tracking allows for good integration but is susceptible to distortion through metal or electro-magnetic interference, which may be caused by the operation table or a robotic system. We have investigated whether magnetic tracking can be used in combination with the da Vinci(®) (DV) telemanipulator in terms of stability and precision. We used a common magnetic tracking system (Aurora(®), NDI Inc.) with the DV in a typical operation setup. Magnetic field distortion was evaluated using a measuring facility, with the following reference system: without any metal (R), operation table alone (T), DV in standby (D) and DV in motion (Dm). The maximum error of the entire tracking volume for R, T, D and Dm was 9.9, 32.8, 37.9 and 37.2 mm, respectively. Limiting the tracking volume to 190 mm (from cranial to caudal) resulted in a maximum error of 4.0, 8.3, 8.5 and 8.9 mm, respectively. When used in the operation room, magnetic tracking shows high errors, mainly due to the operation table. The target area should be limited to increase accuracy, which is possible for most surgical applications. The use of the da Vinci(®) telemanipulator only slightly aggravates the distortion and can thus be used in combination with magnetic tracking systems.

Status of robotic assistance--a less traumatic and more accurate minimally invasive surgery?

PURPOSE: Robotic assistance is considered one innovation within abdominal surgery over the past decade that has the potential to compensate for the drawbacks of conventional laparoscopy, such as limited degree of freedom, 2D vision, fulcrum, and pivoting effect. Robotic systems provide corresponding solutions as 3D view, intuitive motion and enable additional degrees of freedom. This review provides an overview of the history of medical robotics, experimental studies, clinical state-of-the-art and economic impact. METHODS: The Medline database was searched for the terms "robot, telemanipulat, and laparoscop." A total of 2,573 references were found. All references were considered for information on robotic assistance in advanced laparoscopy. Further references were obtained through cross-referencing the bibliography cited in each work. RESULTS: In experimental studies, current robotic systems showed superior handling and ergonomics compared to conventional laparoscopic techniques. In gynecology especially for hysterectomy and in urology especially for prostatectomy, two procedures formerly performed via an open approach, the robot enables a laparoscopic approach. This results in reduced need for pain medication, less blood loss, and shorter hospital stay. Within abdominal surgery, clinical studies were generally unable to prove a benefit of the robot. While the benefit still remains open to discussion, robotic systems are spreading and are available worldwide in tertiary centers. CONCLUSION: Robotic assistance will remain an intensively discussed subject since clinical benefits for most procedures have not yet been proven. The most promising procedures are those in which the robot enables a laparoscopic approach where open surgery is usually required.

Renal artery embolization combined with radiofrequency ablation in a porcine kidney model: effect of small and narrowly calibrated microparticles as embolization material on coagulation diameter, volume, and shape.

The purpose of this study was to evaluate the effect of renal artery embolization with small and narrowly calibrated microparticles on the coagulation diameter, volume, and shape of radiofrequency ablations (RFAs) in porcine kidneys. Forty-eight RFAs were performed in 24 kidneys of 12 pigs. In 6 animals, bilateral renal artery embolization was performed with small and narrowly calibrated microparticles. Upper and lower kidney poles were ablated with identical system parameters. Applying three-dimensional segmentation software, RFAs were segmented on registered 2 mm-thin macroscopic slices. Length, depth, width, volume_segmented, and volume_calculated were determined to describe the size of the RFAs. To evaluate the shape of the RFAs, depth-to-width ratio (perfect symmetry-to-lesion length was indicated by a ratio of 1), sphericity ratio (perfect sphere was indicated by a sphericity ratio of 1), eccentricity (perfect sphere was indicated by an eccentricity of 0), and circularity (perfect circle was indicated by a circularity of 1) were determined. Embolized compared with nonembolized RFAs showed significantly greater depth (23.4 ± 3.6 vs. 17.2 ± 1.8 mm; p < 0.001) and width (20.1 ± 2.9 vs. 12.6 ± 3.7 mm; p < 0.001); significantly larger volume_segmented (8.6 ± 3.2 vs. 3.0 ± 0.7 ml; p < 0.001) and volume_calculated (8.4 ± 3.0 ml vs. 3.3 ± 1.1 ml; p < 0.001); significantly lower depth-to-width (1.17 ± 0.10 vs. 1.48 ± 0.44; p < 0.05), sphericity (1.55 ± 0.44 vs. 1.96 ± 0.43; p < 0.01), and eccentricity (0.84 ± 0.61 vs. 1.73 ± 0.91; p < 0.01) ratios; and significantly greater circularity (0.62 ± 0.14 vs. 0.45 ± 0.16; p < 0.01). Renal artery embolization with small and narrowly calibrated microparticles affected the coagulation diameter, volume, and shape of RFAs in porcine kidneys. Embolized RFAs were significantly larger and more spherical compared with nonembolized RFAs.

Intravenous 64-multi-detector row CT-cholangiography of porcine livers: a feasibility study with definition of the temporal window for optimal bile duct delineation.

BACKGROUND/PURPOSE: To assess the feasibility of intravenous 64-multi-detector row computed tomography (CT)-cholangiography of porcine livers with definition of the temporal window for optimal bile duct delineation. METHODS: Six healthy Landrace pigs, each weighing 28.97 +/- 2.99 kg, underwent 64-multi-detector row CT-cholangiography. Each pig was infused with 50 ml of meglumine iotroxate continuously over a period of 20 min and, starting with the initiation of the infusion, 18 consecutive CT scans of the abdomen at 2-min intervals were acquired. All series were evaluated for bile duct visualization scores and maximum bile duct diameters as primary study goals and bile duct attenuation and liver enhancement as secondary study goals. RESULTS: Of the 16 analyzed biliary tract segments, maximum bile duct visualization scores ranged between 4.00 +/- 0.00 and 2.83 +/- 1.47. Time to maximum bile duct visualization scores ranged between 10 and 34 min. Average bile duct visualization scores for the 10- to 34-min interval ranged between 3.99 +/- 0.05 and 2.78 +/- 0.10. Maximum bile duct diameters ranged between 6.47 +/- 1.05 and 2.65 +/- 2.23 mm. Time to maximum bile duct diameters ranged between 24 and 34 min. Average bile duct diameters for the 10- to 34-min interval ranged between 6.00 +/- 0.38 and 2.40 +/- 0.13 mm. CONCLUSIONS: Intravenous 64-multi-detector row CT-cholangiography of non-diseased porcine liver is feasible, with the best bile duct delineation acquired between 10 and 34 min after initiation of the contrast agent infusion.

Effect of intravenous morphine comedication on bile duct visualization, diameter and volume applying intravenous CT cholangiography in a porcine liver model.

BACKGROUND/AIMS: To determine whether intravenous morphine comedication improves bile duct visualization, diameter and/or volume applying intravenous CT cholangiography in a porcine liver model. METHODS: 12 Landrace pigs underwent intravenous CT cholangiography. Eight minutes after initiation of the contrast material infusion, either morphine sulfate (n = 6 animals) or normal saline (n = 6 animals) was administered. Eighteen consecutive CT scans of the liver were acquired with 2-min intervals starting with initiation of the contrast material infusion. Maximum bile duct visualization scores, diameters and volumes and time to maximum bile duct visualization scores, diameters and volumes were determined. RESULTS: Maximum bile duct visualization scores, diameters and volumes and time to maximum bile duct visualization scores, diameters and volumes were not significantly different when the morphine group was compared to the normal saline group. Maximum bile duct visualization scores ranged between 4.00 ± 0.00 and 2.83 ± 1.47. Maximum bile duct diameters ranged between 6.77 ± 0.40 and 2.10 ± 1.35 mm. Maximum bile duct volume was 16.41 ± 7.33 ml in the morphine group and 16.79 ± 5.65 ml in the normal saline group. CONCLUSION: Intravenous morphine comedication failed to improve bile duct visualization and to increase bile duct diameter and volume applying CT cholangiography.

Increased expression of ALCAM/CD166 in pancreatic cancer is an independent prognostic marker for poor survival and early tumour relapse.

BACKGROUND: ALCAM (activated leucocyte cell adhesion molecule, synonym CD166) is a cell adhesion molecule, which belongs to the Ig superfamily. Disruption of the ALCAM-mediated adhesiveness by proteolytic sheddases such as ADAM17 has been suggested to have a relevant impact on tumour invasion. Although the expression of ALCAM is a valuable prognostic and predictive marker in several types of epithelial tumours, its role as a prognostic marker in pancreatic cancer has not yet been reported. METHODS: In this study, paraffin-embedded samples of 97 patients with pancreatic cancer undergoing potentially curative resection were immunostained against ALCAM, ADAM17 and CK19. Expression of ALCAM and ADAM17 was semiquantitatively evaluated and correlated to clinical and histopathological parameters. RESULTS: We could show that in normal pancreatic tissue, ALCAM is predominantly expressed at the cellular membrane, whereas in pancreatic tumour cells, it is mainly localised in the cytoplasm. In addition, univariate and multivariate analyses show that increased expression of ALCAM is an adverse prognostic factor for recurrence-free and overall survival. Overexpression of ADAM17 in pancreatic cancer, however, failed to be a significant prognostic marker and was not coexpressed with ALCAM. CONCLUSIONS: Our findings support the hypothesis that the disruption of ALCAM-mediated adhesiveness is a relevant step in pancreatic cancer progression. Moreover, ALCAM overexpression is a relevant independent prognostic marker for poor survival and early tumour relapse in pancreatic cancer.

A quality-refinement process for medical imaging applications.

OBJECTIVES: To introduce and evaluate a process for refinement of software quality that is suitable to research groups. In order to avoid constraining researchers too much, the quality improvement process has to be designed carefully. The scope of this paper is to present and evaluate a process to advance quality aspects of existing research prototypes in order to make them ready for initial clinical studies. The proposed process is tailored for research environments and therefore more lightweight than traditional quality management processes. METHODS: Focus on quality criteria that are important at the given stage of the software life cycle. Usage of tools that automate aspects of the process is emphasized. To evaluate the additional effort that comes along with the process, it was exemplarily applied for eight prototypical software modules for medical image processing. RESULTS: The introduced process has been applied to improve the quality of all prototypes so that they could be successfully used in clinical studies. The quality refinement yielded an average of 13 person days of additional effort per project. Overall, 107 bugs were found and resolved by applying the process. CONCLUSIONS: Careful selection of quality criteria and the usage of automated process tools lead to a lightweight quality refinement process suitable for scientific research groups that can be applied to ensure a successful transfer of technical software prototypes into clinical research workflows.