Wide-angle Endoscope Research Articles

Artificial Intelligence for Colonic Polyp and Adenoma Detection: The Way Forward

Colorectal cancer (CRC) is one of the leading cause of cancer deaths worldwide and increasing use of screening colonoscopy has reduced the CRC related mortality.[1] [2] The adenoma miss rate has been shown to be 25% for any adenoma and 27% for serrated polyps in a meta-analysis.[3] This may explain the occurrence of interval cancer. Adenoma detection rate (ADR) is one of the important quality indicators of colonoscopy. An improvement in the ADR is associated with lower interval CRCs and lower mortality.[4] [5] New technologies have been reported in the literature to improve ADR, including enhanced optics, endocuff attachments, extra wide angle endoscopes and cap-assisted techniques to have a better mucosa visualization and eventually reduce the adenoma miss rate.

How I Do It: endoscope-assisted resection of a large dumbbell-shaped cervical schwannoma.

Cervical dumbbell-shaped schwannomas are often challenging in terms of complete resection. There are few reports on the use of endoscope-assisted surgery for foraminal schwannomas. We used the wide-angle endoscope to assist in resecting a large cervical 3-4 dumbbell-shaped schwannoma. The well-designed set-up allowed the surgeon to achieve easier manipulation ins a straight surgical trajectory with minimal intraoperative adjustment. The endoscope allowed surgeons to visualize and operate in regions beyond the straight line of sight, without the need for facetectomy and subdural inspection. We believe that this case demonstrates the feasibility of applying endoscope-assisted surgery for large cervical dumbbell-shaped schwannomas.

Panoramic colonoscopy in colorectal cancer screening - a randomized controlled trial.

IntroductionColonoscopy is considered the gold standard for colorectal cancer screening. Panoramic colonoscopy offers better visualization to decrease the adenoma miss rate.AimTo assess the influence of 330° panoramic view colonoscopy on adenoma and polyp detection rate, cecal intubation time, and examiner’s comfort.Material and methodsThe study enrolled 421 patients aged 18–80 years who were eligible for colonoscopy screening. Patients with prior abdominal surgery, inflammatory bowel disease or after colorectal resections were excluded from the study. Patients were randomized to either standard frontal view (SFV) (Olympus Evis Exera III 190 CF-HQ190L) or the panoramic view colonoscopy (PVC) (FUSE CDVL slim c38). The study was approved by the local bioethics committee and registered at ClinicalTrial.gov (NCT02929381).ResultsThere were 214 patients examined with SFV and 207 with PVC. The mean age of patients was 64 ±12.26 years. The two groups were comparable. The median cecal intubation time was 234 s with SFV vs. 311 s with PVC (p < 0.001). There were no significant differences in CIR or withdrawal time. PVC made it possible to discover more diverticula in the ascending colon (p = 0.009). PDR with SFV was 34.6% and 40.1% with PVC (p = 0.242). A higher number of polyps was found in the transverse colon in the PVC group (p = 0.006). ADR and advanced ADR (aADR) in both groups were similar (26.4% vs. 27.1% and 14, 2% vs. 13.9%).ConclusionsColonoscopy with wide-angle endoscopes lasts longer and allows for the detection of more polyps and diverticula without affecting ADR and aADR. Our study did not reveal the superiority of wide-angle colonoscopy in colorectal cancer screening

A hands-free region-of-interest selection interface for solo surgery with a wide-angle endoscope: preclinical proof of concept

A hands-free region-of-interest (ROI) selection interface is proposed for solo surgery using a wide-angle endoscope. A wide-angle endoscope provides images with a larger field of view than a conventional endoscope. With an appropriate selection interface for a ROI, surgeons can also obtain a detailed local view as if they moved a conventional endoscope in a specific position and direction. To manipulate the endoscope without releasing the surgical instrument in hand, a mini-camera is attached to the instrument, and the images taken by the attached camera are analyzed. When a surgeon moves the instrument, the instrument orientation is calculated by an image processing. Surgeons can select the ROI with this instrument movement after switching from 'task mode' to 'selection mode.' The accelerated KAZE algorithm is used to track the features of the camera images once the instrument is moved. Both the wide-angle and detailed local views are displayed simultaneously, and a surgeon can move the local view area by moving the mini-camera attached to the surgical instrument. Local view selection for a solo surgery was performed without releasing the instrument. The accuracy of camera pose estimation was not significantly different between camera resolutions, but it was significantly different between background camera images with different numbers of features (P<0.01). The success rate of ROI selection diminished as the number of separated regions increased. However, separated regions up to 12 with a region size of 160×160 pixels were selected with no failure. Surgical tasks on a phantom model and a cadaver were attempted to verify the feasibility in a clinical environment. Hands-free endoscope manipulation without releasing the instruments in hand was achieved. The proposed method requires only a small, low-cost camera and an image processing. The technique enables surgeons to perform solo surgeries without a camera assistant.

Design of a foveated wide-angle endoscopic lens

Recent improvements in optics miniaturization have led to the development of multiple techniques in order to perform minimally invasive endoscopic procedures. Among them, the wide-angle lens is often used for its simplicity and ability to collect a large amount of information in one capture. We report the design and analysis of two versions of a wide-angle endoscope with a full field of view of 180 deg. The difference between the two designs resides in the direct control over distortion that was used in order to achieve foveated imaging. By doing so, the local magnification at the center of the image can be controlled during the design process, allowing for a better resolution in the center of the field of view. The design is also folded in order to address certain issue concerning the region of interest during an endoscopic procedure.

Region of Interest Selection Interface for Wide-Angle Arthroscope

We have proposed a new interface for an wide-angle endoscope for solo surgery. The wide-angle arthroscopic view and magnified region of interest (ROI) within the wide view were shown simultaneously. With a camera affixed to surgical instruments, the position of the ROI could be determined by manipulating the surgical instrument. Image features acquired by the A-KAZE approach were used to estimate the change of position of the surgical instrument by tracking the features every time the camera moved. We examined the accuracy of ROI selection using three different images, which were different-sized square arrays and tested phantom experiments. When the number of ROIs was twelve, the success rate was best, and the rate diminished as the size of ROIs decreased. The experimental results showed that the method of using a camera without additional sensors satisfied the appropriate accuracy required for ROI selection, and this interface was helpful in performing surgery with fewer assistants.

Screening colonoscopy: should we focus more on technique and less on technology?

Several large studies have confirmed that high quality colonoscopic surveillance can improve outcomes with substantial reduction in colorectal cancer rates. In order to improve outcomes from screening colonoscopy and help detect adenomas, the emphasis has been mainly on improvements in technology like high-resolution scopes, computerized as well as dye-based chromoendoscopy and wide-angle endoscopes. In addition to the equipment and technological innovation in the equipment used, a number of other factors like experience of the endoscopist, optimal withdrawal techniques, position changes during colonoscopy and bowel preparation can all influence adenoma detection and thereby the quality of colonoscopic surveillance. In this review we will focus on recent studies investigating these aspects of colonoscopy and their impact on adenoma or polyp detection.

Development of high-speed and wide-angle visible observation diagnostics on Experimental Advanced Superconducting Tokamak using catadioptric optics

A new wide-angle endoscope for visible light observation on the Experimental Advanced Superconducting Tokamak (EAST) has been recently developed. The head section of the optical system is based on a mirror reflection design that is similar to the International Thermonuclear Experimental Reactor-like wide-angle observation diagnostic on the Joint European Torus. However, the optical system design has been simplified and improved. As a result, the global transmittance of the system is as high as 79.6% in the wavelength range from 380 to 780 nm, and the spatial resolution is <5 mm for the full depth of field (4000 mm). The optical system also has a large relative aperture (1:2.4) and can be applied in high-speed camera diagnostics. As an important diagnostic tool, the optical system has been installed on the HT-7 (Hefei Tokamak-7) for its final experimental campaign, and the experiments confirmed that it can be applied to the investigation of transient processes in plasma, such as ELMy eruptions in H-mode, on EAST.

Aspirated Voice Prosthesis: A Unique Complication of Post Total Laryngectomy Voice Rehabilitation

ABSTRACTBackground/objectivesProsthetic voice rehabilitation after total laryngectomy has proven to be successful in restoring proper speech function in over 90% of patients. The possibility of achieving effective speech using the voice prosthesis is superior to esophageal speech and electrolarynx.SettingDepartment of Head and Neck Oncosurgery, Kidwai Memorial Institute of Oncology, Bengaluru.Case reportA 75-year-old female who had undergone wide field laryngectomy 14 months back came with history of lost voice prosthesis which was later found aspirated. It was removed by the bronchoscopic forceps under topical anesthesia by visualizing it by a nasal 0° wide angle endoscope. The puncture site was cleaned and allowed to cicatrize and narrow down. The fistula was closed by topical application of silver nitrate.ConclusionTracheoesophageal puncture and prosthesis rehabilitation has emerged as the standard voice rehabilitation of laryngectomized patients. Patient education regarding maintenance of the prosthesis and the care for the tracheostoma is important in reducing the complications.How to cite this articleNaik SM. Aspirated Voice Prosthesis: A Unique Complication of Post Total Laryngectomy Voice Rehabilitation. Int J Phonosurg Laryngol 2012;2(1):41-45.

Water Infusion in Lieu of Air Insufflation and Suction Removal of Residual Air (Water Method) Significantly Increased Adenoma Detection Rate (ADR) in the Proximal Colon Based on Data Derived from Two RCT in U.S. Veterans

Purpose: Case-control reports suggested that colonoscopy failed to reduce incident cancers and cancer mortality in the right colon (Gastro 2004;127:452; AIM 2009;150:1; JNCI 2010;102:89). ADR, but not cecal intubation rate, was an independent predictor of the risk of interval colorectal cancer after screening colonoscopy (NEJM 2010; 362: 1795). The impact of high-definition, wide-angle endoscope (Gastro 2008; 135: 1062), narrow band imaging (Gastro 2009; 136: 410), dye-spray chromoendoscopy (Endoscopy 2006; 38: 444), withdrawal time >6 min (Gastro 2008; 135: 1892) or modifying bowel preparation (AJG doi:10.1038/ajg.2010.160) on ADR was inconclusive. A “colonoscopist-controlled” technique to obviate “missed” right-sided lesions is needed. The water method, albeit awkward, cumbersome and non conventional; but when executed “correctly” increases proximal ADR (GIE 2010; 71: AB248) merits consideration. The purpose of the report is to determine if the water method significantly increases proximal colon ADR in the results of two RCT with non-ADR-related primary outcomes. Methods: The water method was implemented by turning off the air pump prior to insertion of the colonoscope into the rectum. Residual air was suctioned to minimize angulations of flexures. Warm water was infused to assist in identification of the lumen. Residual fecal matter was aspirated before additional clean water was infused. Two RCT were conducted at two VA facilities to determine if the water method increased the proportion of patients who could complete colonoscopy without sedation when the option of scheduled, unsedated (N=82) or on demand sedation (N=100) was used. As part of the protocol overall ADR (proportion of patients with at least one adenoma) and ADR in the proximal colon were tracked in both RCT. Results: Randomization revealed balanced demographic and clinical variables. The water method yielded significantly higher ADR in the proximal colon. Conclusion: The data derived from two RCT revealed that the water method significantly increased ADR in the proximal colon. The results support the hypothesis that the “correct” use of the water method was associated with fewer “missed lesions” in the right colon. Assessment of its impact on interval colorectal cancer after screening colonoscopy deserves to be supported (Supported in part by ACG clinical research award).Table

Comparison of standard vs high‐definition, wide‐angle colonoscopy for polyp detection: a randomized controlled trial

We sought to compare the performance of colonoscopy using a high-definition, wide-angle endoscope vs a standard colonoscope for the detection of polyps. A total of 390 patients were prospectively randomized into high-definition colonoscopy group (HD, n = 193) and standard colonoscopy group (SC, n = 197). Analysis demonstrated that there were significant differences between the two groups, as far as the overall rate of polyps (SC, 1.31 ± 1.90; HD, 1.76 ± 2.31; P = 0.03) and the rate of small hyperplastic polyps (size < 5 mm; SC, 0.10 ± 0.36; HD, 0.25 ± 0.61; P = 0.003) were concerned. No significant differences between the two groups were observed, regarding large polyps (size ≥ 10 mm; SC, 0.39 ± 0.89; HD, 0.48 ± 0.80; P = 0.10), medium polyps (10 mm > size ≥ 5 mm; SC, 0.60 ± 1.46; HD, 0.58 ± 1.25; P = 0.31) and small polyps (size < 5 mm; SC, 0.32 ± 0.86; HD, 0.71 ± 1.65; P = 0.09). Similarly, no significant differences were demonstrated in the detection rate of adenomas and hyperplastic polyps, large adenomas, medium adenomas, small adenomas and large and medium hyperplastic polyps. High-definition colonoscopy led to a significant increase in the polyp detection.

Impact of Wide-Angle, High-Definition Endoscopy in the Diagnosis of Colorectal Neoplasia: A Randomized Controlled Trial

It is essential to optimize standard colonoscopy technique to be able to increase polyp detection. We sought to compare the performance of colonoscopy using a high-definition, wide-angle endoscope (HDE) versus a standard colonoscope (SC) for the detection of colorectal neoplasia. All consecutive consenting adult patients referred from primary care centers were included and randomly assigned at a 1:1 ratio to undergo HDE or SC. Times to reach and withdraw from the cecum were measured. Morphology, size, location, and pathologic diagnosis of each polyp were recorded. Sample size calculation resulted in a total of 682 patients needed. A total of 693 consecutive patients fulfilled all inclusion criteria (73 excluded owing to insufficient bowel preparation). Each arm included 310 patients with no baseline characteristic differences. Time to reach the cecum was slightly superior for SC (8.9 +/- 4.8 minutes vs 8.2 +/- 4.5 minutes; P = .055). Pathology examination was feasible in 418 lesions (272 adenomas, 109 hyperplastic polyps, and 37 inflammatory lesions). Both techniques detected a similar number and type of lesions, and there were no differences in the distribution along the colon, in the degree of dysplasia, or morphology of adenomas. The per-patient basis analyses demonstrated that there were no differences between the 2 arms of the study in the detection rates of polyps (SC, 0.84 +/- 1.59; HDE, 0.83 +/- 1.30), adenomas (0.45 +/- 1.07 vs 0.43 +/- 0.87), small adenomas (0.22 +/- 0.71 vs 0.28 +/- 0.78), flat adenomas (0.30 +/- 0.91 vs 0.21 +/- 0.63), or hyperplastic polyps (0.16 +/- 0.50 vs 0.18 +/- 0.54). HDE did not detect significantly more colorectal neoplasia than SC.

Clinical Impact of Wide-Angle, High-Resolution Endoscopy in the Diagnosis of Colorectal Neoplasia in a Non-Selected Population: A Prospective Randomized Controlled Trial

Background: Standard colonoscopy (SC) is unable to detect up to 27% of small adenomas. It is therefore essential to optimize SC technique to be able to increase polyp detection. Recently, a new colonoscope with high-resolution and Wide-angle vision has been commercialized. Aim: To compare the performance of colonoscopy using a high-resolution, wide-angle endoscope (HRE) versus a SC for the detection of colorectal neoplasia, in a non-selected population.Patients and methods: All consecutive consenting adult patients referred from primary care centers for outpatient colonoscopy between September 2006 and July 2007 were included. Exclusion criteria were polyposis syndromes or hereditary nonpolyposis CRC, previous surgical resection of the colon or rectum, or inflammatory bowel disease. Patients were randomly assigned at a 1:1 ratio to undergo HRE or SC. Times to reach and withdraw from the cecum were measured using a stopwatch The quality of preparation was graded. The morphology, size, and location of each polyp as well as the pathological diagnosis were recorded. A sample size calculation was performed, assuming from the most recent previous data that the mean number of adenomas per patient in the control group would be 0.5 ± 0.9. The study was powered to establish a 30% significant increase in the rate of adenoma detection in the HRE group (alpha error = 0.05, beta error = 0.1, drop-outs = 10%). Data obtained have been compared using the Student's t-test or the Chi-squared test, depending on whether quantitative or qualitative variables, respectively, were involved. Results: A total of 693 consecutive patients referred from primary care centers and attending for outpatient colonoscopy fulfilled all inclusion criteria but 73 had to be excluded from further analysis due to insufficient bowel preparation. Tree hundred and ten patients were included in each arm with no basal characteristic differences. Time to reach the cecum was slightly superior for SC but the difference was not statistically significant (8,9 ± 4,8 vs 8,2 ± 4,5 min. p = 0,05). In total, 518 lesions were identified (272 adenomas and 106 hyperplasic). There was no difference between the 2 arms of the study in the detection rates of overall polyps (0,84 ± 1,59 vs 0,83 ± 1,3), overall adenomas (0,45 ± 1,07 vs 0,43 ± 0,87), small adenomas, flat adenomas, hyperplasic polyps or adenomas distribution along the colonConclusion: HRE did not detect significantly more adenomas than SC. In addition, no statistically significant difference was detected in the overall detection of polyps, in the ratio of flat or small adenomas, or in the identification of patients at higher risk for developing CRC.

High-Definition Endoscopy Improves Adenoma Detection

Backgrounds & Aim: The variability in polyp detection during colonoscopy (∼3 and ∼6 fold for adenomas and advanced adenomas, respectively) presents important clinical and medico-legal challenges for endoscopists (Barclay et al., NEJM 2006). Thus, there has been interest in improving endoscopic equipment to mitigate this issue. The recent development of high-definition wide angle endoscopes have been heralded with promise with initial studies suggesting remarkably improved adenoma detection (Rex DKGastroenterology 2007).

Studies of Visualized Diesohol Combustion Phenomena in IDI Engine(CNG and Alternative Fuels, Oxygenated Fuels)

A diesohol fuel (10% bioethanol, 89% Thailand diesel fuel and 1% additive) may be used as an alternative fuel in a compression ignition engine. However, higher compressibility, lower energy content, and lower cetane number of the diesohol tend to increase the ignition delay and reduce engine efficiency. In this study, to get more knowledge on the diesohol combustion characteristics, an experimental study of luminous combustion in a swirl chamber of an IDI engine was performed to compare the combustion phenomena between diesel and diesohol. Two-color method was applied to obtain spatially and temporally resolved two dimentional distributions of flame temperatures and soot in flame. The imaging system used for this study was based on a wide angle endoscope that is mounted in the cylinder head of the combustion chamber. The experiments were carried out on a commercial 2.5 litre IDI engine. Through systematic experiments, it was explored the effect of ethanol in diesohol blend. Observed diesohol fuel sprays have shown either longer spray tip penetration length or wider spray angle than the reference diesel. Images of spray combustion shown in figure 1 indicate that the period of diesohol combustion phenomena occurred more retard with respect to TDC than diesel. As its consequence, together with the lower heat of combustion, the predicted combustion flame temperature and soot in flame density distribution, shown in figure 2 and 3, are lower than the reference diesel. Observation in swirl chamber shows detail of the complex inflammation and combustion processes.

Anatomic study of femoral vein occlusion during simulated hip arthroplasty

An anatomic study was undertaken to establish whether positioning of the leg and surgical approaches for total hip replacement (THR) cause changes in the femoral v. which may contribute to the development of deep vein thrombosis (DVT). The patency of 32 femoral vv. of 18 cadavers was inspected at different levels during simulated THR. Before and after removal of the femoral head through a transgluteal or posterior approach, a wide-angle endoscope was inserted into the femoral v. via the external iliac v. Blood flow was simulated by proximal irrigation with saline through the popliteal v. After removal of the femoral head distinct changes were observed in both approaches. In the transgluteal approach the changes were dependent on the degree of adduction and the body build of the cadaver. Initially, an oval form was seen in a constricted lumen with an increasingly oblique oval deformation and a final facet-like closure, usually at about 5 to 7.5 cm below the inguinal ligament. In total adduction this stenosis occurred regardless of build. Using a posterior approach, the necessary internal rotation caused a closure of the vein in 50% of cases. In combination with flexion and adduction there was stenosis in all cadavers regardless of body build. Our results indicate that the duration of the adducted position of the thigh during THR via a transgluteal approach should be minimised, as there is a reduction in blood flow with even minor degrees of adduction. In the posterior approach the stenosis occurs earlier, and is independent of the build of the cadaver.