Recognition accuracy of tumor extent using a prototype 3D endoscope for superficial gastric tumor: an ex vivo crossover study

Usefulness of three-dimensional imaging in a flexible endoscopic surgery platform with multi-degrees-of-freedom articulating devices

BACKGROUND AND AIMS

Recent studies on endoscopic submucosal dissection have aimed to reduce the difficulty of the procedure by using multi-degrees-of-freedom articulating devices. In this study, we evaluated the usefulness of adding three-dimensional (3D) video imaging into simulated endoscopic submucosal dissection tasks using multi-degrees-of-freedom devices.

METHODS

We designed an endoscopic platform with a 3D camera and two multi-degrees-of-freedom devices. Four ex vivo bench tasks were created, and a crossover study comparing 2D and 3D conditions was conducted on 15 volunteers. In each task, performance such as procedure time and accuracy were objectively evaluated. Additionally, a comprehensive visual analogue scale questionnaire was conducted.

RESULTS

In the tasks simulating submucosal flap grasping, marking, and full-area incision, the use of 3D imaging significantly improved the speed and accuracy of the multi-degrees-of-freedom device manipulation (p < .01). No significant differences were observed in the task that simulated the dissection procedure. Furthermore, it appears that the accuracy of recognizing curved surfaces may be reduced in the 3D environment. Operators reported subjective increases in recognizability and operability with the 3D camera, along with an increase in asthenopia (p < .01).

CONCLUSIONS

3D vision improves the technical accuracy of certain simulated multi-degrees-of-freedom endoscopic submucosal dissection tasks and subjectively improved operating conditions, at the cost of increased eye strain.

Advanced diagnostic endoscopy in the upper gastrointestinal tract: Review of the Japan Gastroenterological Endoscopy Society core sessions

We held four upper gastrointestinal tract advanced diagnostic endoscopy sessions from the 89th to the 92nd Congress of the Japan Gastroenterological Endoscopy Society. The most common region addressed was the stomach in 25 presentations, followed by the esophagus in 23, duodenum in five, and other in one. Looking at techniques discussed, the most common image enhancement method discussed was narrowband imaging in 29 presentations, blue laser imaging, and linked color imaging (LCI) in 10 each, dual red imaging in three, and autofluorescence imaging in one. Furthermore, there were presentations of new techniques such as M-Chromo-LCI and acetic acid-indigo carmine mixture LCI. There were also six presentations regarding probe-based confocal laser endomicroscopy, and one of endocytoscopy techniques. We also saw presentations of images of gastric subepithelial tumors within the submucosa, 3D endoscopy, the development of computer-aided detection systems for early cancers, and fluorescent imaging.

Deep focus light-field camera for handheld 3D intraoral scanning using crosstalk-free solid immersion microlens arrays

3D in vivo imaging techniques facilitate disease tracking and treatment, but bulky configurations and motion artifacts limit practical clinical applications. Compact light-field cameras with microlens arrays offer a feasible option for rapid volumetric imaging, yet their utilization in clinical practice necessitates an increased depth-of-field for handheld operation. Here, we report deep focus light-field camera (DF-LFC) with crosstalk-free solid immersion microlens arrays (siMLAs), allowing large depth-of-field and high-resolution imaging for handheld 3D intraoral scanning. The siMLAs consist of thin PDMS-coated microlens arrays and a metal-insulator-metal absorber to extend the focal length with low optical crosstalk and specular reflection. The experimental results show that the immersion of MLAs in PDMS increases the focal length by a factor of 2.7 and the transmittance by 5.6%-27%. Unlike conventional MLAs, the siMLAs exhibit exceptionally high f-numbers up to f/6, resulting in a large depth-of-field for light-field imaging. The siMLAs were fully integrated into an intraoral scanner to reconstruct a 3D dental phantom with a distance measurement error of 82 ± 41 μm during handheld operation. The DF-LFC offers a new direction not only for digital dental impressions with high accuracy, simplified workflow, reduced waste, and digital compatibility but also for assorted clinical endoscopy and microscopy.

The safety and feasibility of endoscopic submucosal dissection using a flexible three-dimensional endoscope for early gastric cancer and superficial esophageal cancer: A prospective observational study

BACKGROUND AND AIM

Endoscopic submucosal dissection (ESD) is performed as one of standard treatments for patients with early gastric cancer (EGC) and superficial esophageal squamous cancer (SESCC). A prototype of a flexible endoscope with a 3-D system has been recently developed. This study aimed to investigate the safety and feasibility of ESD using a 3-D flexible endoscope (3-D ESD) for EGC and SESCC.

METHODS

This single-center, prospective, observational study enrolled patients who underwent planned 3-D ESD. The clinical outcomes, including the incidence of adverse events and treatment results, were analyzed. Visibility and manipulation during 3-D ESD were evaluated using a visual analog scale (VAS). We also evaluated the effect of the 3-D system on the endoscopist using VAS and the critical flicker fusion frequency (CFFF).

RESULTS

We analyzed 47 EGC and 20 SESCC cases. There are no bleeding cases that required transfusion and perforation during 3-D ESD in both EGC and SESCC patients. However, the incidence of delayed bleeding and delayed perforation was 1.5% (one case) each. The mean VAS scores for recognizing the submucosal layer during the submucosal dissection, visual perception of blood vessel, and depth perception were 72.7 ± 22.2, 74.7 ± 21.8, and 78.2 ± 19.9, respectively. In contrast, the mean VAS score for manipulation was 25.4 ± 19.7. Among endoscopists, there was no significant difference in the VAS of eyestrain and headache before and after ESD, and there was no significant difference in the CFFF.

CONCLUSION

The safety and feasibility of 3-D ESD for EGC and SESCC are acceptable in both patients and endoscopists.

Three-dimensional visualization improves the endoscopic diagnosis of superficial gastric neoplasia

BACKGROUND

Three-dimensional (3D) technology has been used in many fields, including flexible endoscopy. We evaluated the usefulness of 3D visualization for endoscopically diagnosing superficial gastric neoplasia.

METHODS

Twelve participants (4 novices, 4 trainees and 4 experts) evaluated two-dimensional (2D) and 3D endoscopic still images of 28 gastric neoplasias, obtained before ESD with white-light imaging (WLI) and narrow-band imaging (NBI). Assessments of the delineation accuracy of tumor extent and tumor morphology under 2D and 3D visualization were based on the histopathological diagnosis of ESD specimens. Participants answered visual analog scale (VAS) questionnaires (0-10, worst to best) concerning the (a) ease of recognition of lesion morphology, (b) lesion extent and (c) comprehensive endoscopic cognition under 2D and 3D visualization. The endpoints were the accuracy of tumor extent and morphology type and the degree of confidence in assessing (a)-(c).

RESULTS

The delineation accuracy of lesion extent [mean (95% confidence interval)] with WLI under 3D visualization [60.2% (56.1-64.3%)] was significantly higher than that under 2D visualization [52.3% (48.2-56.4%)] (P < 0.001). The accuracy with NBI under 3D visualization [70.3% (66.8-73.7%)] was also significantly higher than that under 2D visualization [64.2% (60.7-67.4%)] (P < 0.001). The accuracy of the morphology type with NBI under 3D visualization was significantly higher than that under 2D visualization (P = 0.004). The VAS for all aspects of endoscopic recognition under 3D visualization was significantly better than that under 2D visualization (P < 0.01).

CONCLUSIONS

Three-dimensional visualization can enhance the diagnostic quality for superficial gastric tumors.

Three-dimensional flexible endoscopy enables more accurate endoscopic recognition and endoscopic submucosal dissection marking for superficial gastric neoplasia: a pilot study to compare two- and three-dimensional imaging

BACKGROUND

Three-dimensional (3D) visualization offers better depth recognition than two-dimensional (2D) imaging, thus helping to provide more useful information. We compared 3D and 2D endoscopy with regard to endoscopic recognition and endoscopic submucosal dissection (ESD) marking for superficial gastric neoplasia.

METHODS

ESD marking was performed on half of a neoplasia margin under 2D observation and the on other half under 3D observation for 28 gastric lesions (26 early gastric cancers and 2 adenomas). The accuracy of ESD marking was evaluated based on the distance between the pathological and endoscopic neoplasia margins measured on histology sections of ESD specimens. The technical ease of ESD marking and endoscopic lesion recognition (lesion morphology, lesion extent, and comprehensive endoscopic cognition) were assessed using visual analog scale (VAS) questionnaires.

RESULTS

The mean distance between the pathological and endoscopic margins under 3D observation (1.03 ± 0.80 mm) was significantly (p = 0.002) shorter than that under 2D observation (1.94 ± 1.96 mm). The VAS for technical ease of ESD marking under 3D observation was significantly better (p < 0.01) than that under 2D observation. The VAS for all aspects of endoscopic recognition under 3D observation was significantly better (p < 0.01) than under 2D observation.

CONCLUSIONS

3D flexible endoscopy achieved more accurate endoscopic recognition and ESD marking for superficial gastric neoplasia than a 2D approach in a clinical setting of ESD.

Three-Dimensional Flexible Endoscopy Can Facilitate Efficient and Reliable Endoscopic Hand Suturing: An ex-vivo Study

BACKGROUND/AIMS

Three-dimensional (3D) flexible endoscopy, a new imaging modality that provides a stereoscopic view, can facilitate endoscopic hand suturing (EHS), a novel intraluminal suturing technique. This ex-vivo pilot study evaluated the usefulness of 3D endoscopy in EHS.

METHODS

Four endoscopists (two certified, two non-certified) performed EHS in six sessions on a soft resin pad. Each session involved five stitches, under alternating 3D and two-dimensional (2D) conditions. Suturing time (sec/session), changes in suturing time, and accuracy of suturing were compared between 2D and 3D conditions.

RESULTS

The mean suturing time was shorter in 3D than in 2D (9.8±3.4 min/session vs. 11.2±5.1 min/session) conditions and EHS was completed faster in 3D conditions, particularly by non-certified endoscopists. The suturing speed increased as the 3D sessions progressed. Error rates (failure to grasp the needle, failure to thread the needle, and puncture retrial) in the 3D condition were lower than those in the 2D condition, whereas there was no apparent difference in deviation distance.

CONCLUSION

3D endoscopy may contribute to increasing the speed and accuracy of EHS in a short time period. Stereoscopic viewing during 3D endoscopy may help in efficient skill acquisition for EHS, particularly among novice endoscopists.

Stereoscopic versus monoscopic displays: Learning fine manual dexterity skills using a microsurgical task simulator

We investigated the learning of fine manual dexterity with a microsurgical instrument and a new simulator in a context of microsurgery. 30 subjects were divided into two groups. One (3D group) interacted with a stereoscopic and the other (2D group) with a monoscopic display. Visual information for the displays was captured from a surgical stereomicroscope. In 20 trials, both groups performed the repetitive tasks of picking up small rods from a funnel-shaped cavity and placing them outside. In analysing learning curves, we found that the initial learning process for hand-eye coordination is easier with a 3D display, and that performance persists at a higher level of proficiency than with the 2D display option. Thus stereoscopic displays can be especially beneficial for novices, for those learning new procedures, or for providing orientation to operators facing a new or altered spatial situation. Simulators with few reliefs or spatial textures should not be used for comparison between 3D and 2D viewing conditions.

How I do it: Flexible 3-D endoscope for endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) is technically challenging as a result of a lack of depth perception. The present article investigated the 3-D endoscope for carrying out ESD and translated the technique from bench to clinical use. In a preclinical porcine experiment, ESD using a 3-D endoscope was compared between an experienced and a novice endoscopist. All ESD were completed without perforation. Median operative time per surface area was significantly lower for the experienced endoscopist than for the novice (197.9 s/cm² vs 434.7 s/cm² ; P = 0.05). The second part was a prospective clinical experience to evaluate use of the 3-D endoscope for carrying out ESD. Ten patients received ESD using the 3-D endoscope. Four patients had gastric ESD, two had duodenal ESD and four had sigmoid and rectal ESD. There were no complications, whereas ESD failed in one patient who had gastric neoplasia at anastomosis. Mean operative time was 99.4 min, and operative time per surface area resection was 391 s/cm² . The operating endoscopist did not complain of motion sickness, whereas the assistants had some dizziness upon prolonged ESD procedure. This study showed that carrying out ESD was safe and effective using a 3-D endoscope with an excellent 3-D view enhancing depth perception. Future study should be conducted to compare 3-D against 2-D endoscopes for ESD.

Comparison of 3D endoscopy and conventional 2D endoscopy in gastric endoscopic submucosal dissection: an ex vivo animal study

BACKGROUND AND OBJECTIVES

Conventional endoscopy provides two-dimensional (2D) information without depth information. This study compared three-dimensional (3D) endoscopy and 2D endoscopy using an endoscopic submucosal dissection (ESD) training model to evaluate the utility of 3D endoscopy.

METHODS

Porcine stomach specimens (7 × 7 cm) were prepared from commercially available resected porcine stomachs and a 10-mm hypothetical lesion was marked at the center of each specimen. Specimens were individually placed in an ESD training model, and subjected to either 2D or 3D ESD. En bloc resection rate, perforation rate, incision time, dissection time, and levels of five eyestrain symptoms (fatigue, pain, blurred vision, head-heaviness, and headache; 100-mm visual analog scale) were compared between the 2D and 3D procedures. In a crossover design, 8 endoscopists each performed two 2D and two 3D procedures.

RESULTS

All 32 lesions were resected en block, but perforation occurred in one 2D procedure. Incision time was significantly shorter in 3D ESD than in 2D ESD (102.8 ± 42.1 s vs. 135.8 ± 65.7 s, p < 0.05). Dissection time was also significantly shorter in 3D ESD than in 2D ESD (366.3 ± 187.6 s vs. 517.8 ± 282.3 s, p < 0.05). Differences in levels of all symptoms except blurred vision between before and after ESD were larger in 3D ESD than in 2D ESD.

CONCLUSIONS

Incision time and dissection time were significantly shorter in 3D ESD compared with 2D ESD, but eyestrain was increased. Depth information from 3D images appears to facilitate rapid and stable ESD maneuvers.

Operational effectiveness of three-dimensional flexible endoscopy: an ex vivo study using a new model

BACKGROUND AND OBJECTIVES

Two-dimensional (2D) images lack depth information and thus provide probabilistic recognition that do not completely match the actual three-dimensional (3D) information. Here, we investigated the operability of 3D endoscopes.

METHODS

A 3D operation model was developed by passing 20 silk threads through upper and lower plates at 2-mm intervals in front and back rows separated by 1 mm. We evaluated accuracy and time of operating an electrosurgical knife. A successful operation was defined as pulling only a front-row thread; an unsuccessful operation was defined as pulling no thread (miss) or simultaneously pulling front- and back-row threads. Endoscopists (four experts, six trainees) repeated the operation under 2D and 3D conditions until individually accumulating 10 successful attempts under each condition.

RESULTS

Operation accuracy was significantly higher for 3D compared with 2D in all endoscopists (88.5% vs. 61.3%; p < 0.01) and in both experience groups (trainees: 84.5% vs. 61.2%; experts: 95.2% vs. 61.5%; both p < 0.01). Operation time was significantly shorter for 3D compared with 2D in all endoscopists (12.5 ± 4.1 s vs. 14.8 ± 4.7 s; p < 0.01) and in both experience groups (trainees: 12.8 ± 4.2 s vs. 15.2 ± 4.9 s; experts: 12.1 ± 4.0 s vs. 14.3 ± 4.3 s; both p < 0.01).

DISCUSSION

Compared with 2D endoscopy, 3D endoscopy significantly improved operation accuracy and shortened operation time, suggesting that 3D endoscopy enables accurate operation by depth information, aiding spatial recognition.