Background
Though theoretically superior to standard 2D visualization, 3D video systems have not yet achieved a breakthrough in laparoscopy. The latest 3D monitors, including autostereoscopic ...displays and high-definition (HD) resolution, are designed to overcome the existing limitations.
Methods
We performed a randomized study on 48 individuals with different experience levels in laparoscopy. Three different 3D displays (glasses-based 3D monitor, autostereoscopic display, and a mirror-based theoretically ideal 3D display) were compared to a 2D HD display by assessing multiple performance and mental workload parameters and rating the subjects during a laparoscopic suturing task. Electromagnetic tracking provided information on the instruments’ pathlength, movement velocity, and economy. The usability, the perception of visual discomfort, and the quality of image transmission of each monitor were subjectively rated.
Results
Almost all performance parameters were superior with the conventional glasses-based 3D display compared to the 2D display and the autostereoscopic display, but were often significantly exceeded by the mirror-based 3D display. Subjects performed a task faster and with greater precision when visualization was achieved with the 3D and the mirror-based display. Instrument pathlength was shortened by improved depth perception. Workload parameters (NASA TLX) did not show significant differences. Test persons complained of impaired vision while using the autostereoscopic monitor. The 3D and 2D displays were rated user-friendly and applicable in daily work. Experienced and inexperienced laparoscopists profited equally from using a 3D display, with an improvement in task performance about 20 %.
Conclusion
Novel 3D displays improve laparoscopic interventions as a result of faster performance and higher precision without causing a higher mental workload. Therefore, they have the potential to significantly impact the further development of minimally invasive surgery. However, as shown by the custom-built 3D mirror display, this effect can be improved, thus stimulating further research.
Endoscopic resection of gastric subepithelial tumors (SETs) carries a high risk of perforation. New techniques such as use of the over-the-scope clip (OTSC) may enable secure endoscopic closure of ...perforations. We aimed to evaluate the feasibility of endoscopic resection of small gastric SETs using a grasp-and-snare technique followed by OTSC closure of the gastric wall if necessary.
In this prospective study 20 consecutive patients who presented with gastric SETs ≤ 3 cm were enrolled. Endoscopic resection was performed using a double-channel endoscope, a tissue anchor and a monofilament snare. If perforation occurred, the aim was to achieve complete closure with a tissue twin grasper and the OTSC. Procedures were performed under laparoscopic control using a 5-mm optic, which was introduced via a single 5-mm trocar through the umbilicus. All patients were followed up for 3 months after the procedure.
In 6 /20 patients a pure endoscopic approach was impossible and a switch to laparoscopic wedge resection was necessary (large tumor size in 2 /6 patients; mainly extraluminal growth in 4 /6 patients). Solely endoscopic resection was successfully performed in the remaining 14 patients. Amongst these, laparoscopic control was impossible in two cases. Perforation occurred in 6 /14 patients but gastric closure with the OTSC was performed successfully in all these cases. No complications occurred and follow-up was unremarkable.
Endoscopic snare resection enables safe treatment of small gastric SETs (diameter ≤ 3 cm) and seems faster and easier to perform than other endoscopic resection techniques, such as endoscopic submucosal dissection (ESD) or submucosal tunneling. Perforations occurring after full-thickness resection can be adequately managed by OTSC closure. Solely endoscopic resection without laparoscopic control seems possible in selected patients with tumors known to have purely intraluminal growth.
Objectives
To evaluate a new iterative reconstruction (IR) algorithm for radiation dose, image quality (IQ), signal-to-noise-ratio (SNR), and contrast-to-noise-ratio (CNR) in multidetector computed ...tomography (MDCT) dynamic myocardial perfusion imaging (MPI).
Methods
ECG-gated 256-slice MDCT dynamic MPI was performed in six pigs after subtotal balloon occlusion of one artery. Two 100 kVp protocols were compared: high dose (HD): 150 mAs; low dose (LD): 100 mAs. HD images were reconstructed with filtered back projection (FBP), LD images with FBP and different strengths of IR (L1, L4, and L7). IQ (5-point scale), SNR, and CNR (ischemic vs. normal myocardium) values derived from the HD (FBP) images and the different LD images were compared.
Results
Mean SNR values for myocardium were 16.3, 11.3, 13.1, 17.1, and 28.9 for the HD, LD (FBP), LD (L1), LD (L4), and LD (L7) reconstructions, respectively. Mean CNR values were 8.9, 6.3, 7.8, 9.3, and 12.8. IQ was scored as 4.6, 3.3, 4.4, 4.7, and 3.4, respectively. A significant loss of IQ was observed for the LD (L7) images compared to the HD (FBP) images (
P
< 0.05).
Conclusion
Appropriate levels of iterative reconstruction can improve SNR and CNR, facilitating radiation dose savings in CT-MPI without influencing diagnostic quality.
Key Points
•
Iterative reconstruction (IR) can reduce radiation dose in myocardial perfusion CT.
•
Our study also demonstrated improvements in image quality (noise, SNR, and CNR).
•
Dynamic CT-MPI could help determine the hemodynamic significance of coronary artery disease
.
•
With dynamic CT MPI, myocardial blood flow can be determined quantitatively.
Purpose
Surgical documentation is an important yet time-consuming necessity in clinical routine. Beside its core function to transmit information about a surgery to other medical professionals, the ...surgical report has gained even more significance in terms of information extraction for scientific, administrative and judicial application. A possible basis for computer aided reporting is phase detection by convolutional neural networks (CNN). In this article we propose a workflow to generate operative notes based on the output of the TeCNO CNN.
Methods
Video recordings of 15 cholecystectomies were used for inference. The annotation of TeCNO was compared to that of an expert surgeon (HE) and the algorithm based annotation of a scientist (HA). The CNN output then was used to identify aberrance from standard course as basis for the final report. Moreover, we assessed the phenomenon of ‘phase flickering’ as clusters of incorrectly labeled frames and evaluated its usability.
Results
The accordance of the HE and CNN was 79.7% and that of HA and CNN 87.0%. ‘Phase flickering’ indicated an aberrant course with AUCs of 0.91 and 0.89 in ROC analysis regarding number and extend of concerned frames. Finally, we created operative notes based on a standard text, deviation alerts, and manual completion by the surgeon.
Conclusion
Computer-aided documentation is a noteworthy use case for phase recognition in standardized surgery. The analysis of phase flickering in a CNN’s annotation has the potential of retrieving more information about the course of a particular procedure to complement an automated report.
Background
A reliable and sterile access through the intestinal wall to ease flexible endoscopic transluminal interventions is still appealing but lacks a suitable port system.
Methods
In a granted ...industry cooperation, we developed the MIEO-Port, a flexible three components overtube system that provides a temporary hermetic sealing of the intestinal wall to allow endoscopic disinfection and manipulation to gain access to the abdominal cavity. The port features an innovative head part which allows for coupling the port to the intestinal wall by vacuum suction and for controlled jetting the isolated intestinal surface with a disinfectant. The device was tested in vivo in 6 pigs for acute and long-term usability. All animal tests were approved by the local ethics committee.
Results
In the acute experiment, the port system supported sealed endoscopic mucosa resection and transluminal cholecystectomy. In the survival study on 5 animals, the MIEO-Port proved its reliability after transcolonic peritoneoscopy. In one animal, a port dislocation occurred after extensive retroperitoneal preparation, one animal revealed bacterial contamination at necropsy; however, all animals showed a favourable course over ten days and offered no signs of peritonitis or abscedation during post-mortem examination.
Discussion
To the best of our knowledge, the MIEO-Port system is the first device to provide a reliable and sterile flexible access to the peritoneal cavity that can be used throughout the entire gastrointestinal tract regardless of the access route and which combines hermetic sealing with local sterilization. Further studies are warranted.
Background
Subepithelial gastric tumors are common findings during upper gastrointestinal endoscopy. Tumor resection is mostly done laparoscopically, but there is still discussion concerning the size ...of lesion for which the treatment may be minimally invasive; additionally there is very little data available concerning patient outcome after minor access surgery.
Methods
Clinicopathologic features and survival data of 93 consecutive patients undergoing a combined laparoscopic-endoscopic approach for gastric submucosal tumors were prospectively analyzed. Analysis included preoperative diagnostic work-up, perioperative data, and postoperative complications. Follow-up was carried out for patients with GIST to check for tumor recurrence.
Results
It was possible to resect 88 of 93 lesions by the laparoscopic-endoscopic approach, with tumor-free margins in all patients. Intraoperative endoscopy facilitated exact tumor localization in 92 patients. Most lesions were removed by endoscopic-laparoscopic wedge resection or, less frequently, by a combined transgastric approach. Mean operative time was 90.7 min; the postoperative hospitalization was 7.3 days. Adverse events appeared in 7.5%, and conversion to open surgery was required in 6.5%. For patients suffering from gastrointestinal stromal tumors, there was no tumor recurrence at a mean follow-up of 40 months.
Conclusions
Combined laparoscopic-endoscopic “rendez-vous” procedures are easy to perform and offer a curative approach for almost all gastric submucosal lesions. The technique is associated with low morbidity and short hospitalization. Though even patients with large GISTs of intermediate and high risk were treated, no tumor recurrence has been observed to date.
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