Small-bowel neuroendocrine tumors (NETs) are slow growing, clinically silent tumors whose prognosis depends on disease stage. Members of kindreds with a familial form of small intestinal NETs (SI-NETs) represent a high-risk population for whom early detection improves disease outcome. Our aim was to determine the utility of small-bowel capsule endoscopy (SB-CE) for screening high-risk asymptomatic relatives from kindreds with familial carcinoid.

One hundred seventy-four asymptomatic subjects with a family history (≥2 family members) of SI-NETs were screened under Protocol NCT00646022, Natural History of Familial Carcinoid Tumor at the National Institutes of Health. All patients were imaged with SB-CE and 18fluoro-dihydroxphenylalanine (18F-DOPA) positron emission tomography (PET)/CT, and results were independently analyzed. Patients with a positive imaging study underwent surgical exploration.

Thirty-five of 174 asymptomatic subjects screened for SI-NETs were positive on either SB-CE or 18F-DOPA PET. Thirty-two of 35 patients with a positive study were confirmed at surgery. SB-CE was positive in 28 of 32 patients with confirmed tumors for a per-patient sensitivity of 87.5%. SB-CE had a specificity of 97.3% and a negative predictive value of 96.5%. The average tumor number and size were 7.7 and 5.0 mm, respectively, and 81.2% of patients had multiple tumors. 18F-DOPA PET/CT had a similar sensitivity of 84% versus surgery.

SB-CE is a sensitive and specific method comparable with 18F-DOPA PET/CT for screening high-risk patients with familial SI-NET. (Clinical trial registration number: NCT00646022.).

Endoscopic investigation plays a critical role in the diagnosis of gastrointestinal (GI) diseases. Since 2001, Wireless Capsule Endoscopy (WCE) has been available for small bowel exploration and is in continuous development. Over the last decade, WCE has achieved impressive improvements in areas such as miniaturisation, image quality and battery life. As a result, WCE is currently a very useful alternative to wired enteroscopy in the investigation of various small bowel abnormalities and has the potential to become the leading screening technique for the entire gastrointestinal tract. However, commercial solutions still have several limitations, namely incomplete examination and limited diagnostic capacity. These deficiencies are related to technical issues, such as image quality, motion estimation and power consumption management. Computational methods, based on image processing and analysis, can help to overcome these challenges and reduce both the time required by reviewers and human interpretation errors. Research groups have proposed a series of methods including algorithms for locating the capsule or lesion, assessing intestinal motility and improving image quality.In this work, we provide a critical review of computational vision-based methods for WCE image analysis aimed at overcoming the technological challenges of capsules. This article also reviews several representative public datasets used to evaluate the performance of WCE techniques and methods. Finally, some promising solutions of computational methods based on the analysis of multiple-camera endoscopic images are presented.

Capsule endoscopy (CE) opened a new method for visualization of the small intestine. We here further explore its clinical implications.We retrospectively analyzed the clinical benefit of CE in view of medical history, diagnostics, and therapy. Our patient collective consisted of 203 patients. CE was investigated in the context of bleeding, anemia, abdominal pain, diarrhea, Crohn's disease, and suspected tumors.The study collective consisted of 118 male and 85 female patients with a mean age of 58 years (range 8-90 years). Complete bowel transit took place in 82% of the patients. The diagnostic yield in the detection of obscure gastrointestinal bleeding was 80% and for anemia 78%. Mucosal lesions were the most common finding (43%). Unclear abdominal pain had the lowest diagnostic yield (41%). Ensuing therapeutic interventions were mostly medical (66%), and to a minor extent surgical (4.4%) as well as endoscopic (4%).In conclusion, small intestinal CE is a secure method to clarify small intestinal diseases, especially obscure gastrointestinal bleeding, even in pre-operated patients without stenosis symptoms. Our study emphasizes in a collective of patients with extensive prior diagnostics that due to CE therapeutic measures resulted in 73%.

In recent years, wireless capsule endoscopy (WCE) has been a state-of-the-art tool to examine disorders of the human gastrointestinal tract painlessly. However, system miniaturization, enhancement of the image-data transfer rate and power consumption reduction for the capsule are still key challenges. In this paper, a video capsule endoscopy system with a low-power controlling and processing application-specific integrated circuit (ASIC) is designed and fabricated. In the design, these challenges are resolved by employing a microimage sensor, a novel radio frequency transmitter with an on-off keying modulation rate of 20 Mbps, and an ASIC structure that includes a clock management module, a power-efficient image compression module and a power management unit. An ASIC-based prototype capsule, which measures Φ11 mm × 25 mm, has been developed here. Test results show that the designed ASIC consumes much less power than most of the other WCE systems and that its total power consumption per frame is the least. The image compression module can realize high near-lossless compression rate (3.69) and high image quality (46.2 dB). The proposed system supports multi-spectral imaging, including white light imaging and autofluorescence imaging, at a maximum frame rate of 24 fps and with a resolution of 400 × 400. Tests and in vivo trials in pigs have proved the feasibility of the entire system, but further improvements in capsule control and compression performance inside the ASIC are needed in the future.

Although many groups have attempted to develop an automated computerized method to detect pathology of the small intestinal mucosa caused by celiac disease, the efforts have thus far failed. This is due in part to the occult presence of the disease. When pathological evidence of celiac disease exists in the small bowel it is visually often patchy and subtle. Due to presence of extraneous substances such as air bubbles and opaque fluids, the use of computerized automation methods have only been partially successful in detecting the hallmarks of the disease in the small intestine-villous atrophy, fissuring, and a mottled appearance. By using a variety of computerized techniques and assigning a weight or vote to each technique, it is possible to improve the detection of abnormal regions which are indicative of celiac disease, and of treatment progress in diagnosed patients. Herein a paradigm is suggested for improving the efficacy of automated methods for measuring celiac disease manifestation in the small intestinal mucosa. The suggestions are applicable to both standard and videocapsule endoscopic imaging, since both methods could potentially benefit from computerized quantitation to improve celiac disease diagnosis.

This review presents issues pertaining to lesion detection in small-bowel capsule endoscopy (SBCE). The use of prokinetics, chromoendoscopy, diagnostic yield indicators, localization issues and the use of 3D reconstruction are presented. The authors also review the current status (and future expectations) in automatic lesion detection software development. Automatic lesion detection and reporting, and development of an accurate lesion localization system are the main software challenges of our time. The 'smart', selective and judicious use (before as well as during SBCE) of prokinetics in combination with other modalities (such as real time and/or purge) improves the completion rate of SBCE. The tracking of the capsule within the body is important for the localization of abnormal findings and planning of further therapeutic interventions. Currently, localization is based on transit time. Recently proposed software and hardware solutions are proposed herein. Moreover, the feasibility of software-based 3D representation (attempt for 3D reconstruction) is examined.

Three-dimensional imaging in capsule endoscopy is not currently feasible due to hardware limitations. However, software algorithms that enable three-dimensional reconstruction in capsule endoscopy are available.

Feasibility study. A phantom was designed to test the accuracy of three-dimensional reconstruction. Thereafter, 192 small-bowel capsule endoscopy images (of vascular: 50; inflammatory: 73; protruding structures: 69) were reviewed with the aid of a purpose-built three-dimensional reconstruction software. Seven endoscopists rated visualisation improved or non-improved. Subgroup analyses performed for diagnostic category, diagnosis, image surface morphology and colour and SBCE equipment used (PillCam(®) vs. MiroCam(®)).

Overall, phantom experiments showed that the three-dimensional reconstruction software was accurate at 90% of red, 70% of yellow and 45% of white phantom models. Enhanced visualisation for 56% of vascular, 23% of inflammatory and <10% of protruding structures was noted (P=0.007, 0.172 and 0.008, respectively). Furthermore, three-dimensional software application enhanced 53.7% of red, 21.8% of white, 17.3% of red and white, and 9.2% of images of lesions with colour similar to that of the surrounding mucosa, P<0.0001.

Application of a three-dimensional reconstruction software in capsule endoscopy leads to image enhancement for a significant proportion of vascular, but less so for inflammatory and protruding lesions. Until optics technology allows hardware-enabled three-dimensional reconstruction, it seems a plausible alternative.

The introduction of capsule endoscopy (CE) in clinical practice increased the interest for the study of the small-bowel. Consequently, in about 10 years, an impressive quantity of literature on indications, diagnostic yield (DY), safety profile and technical evolution of CE has been published as well as several reviews. At present time, there are 5 small-bowel capsule enteroscopy (SBCE) models in the worldwide market. Head-to-head trials have showed in the great majority of studies comparable results in terms of DY, image quality and completion rate. CE meta-analyses formed the basis of national/international guidelines; these guidelines place CE in a prime position for the diagnostic work-up of patients with obscure gastrointestinal bleeding, known and/or suspected Crohn's disease and possible small-bowel neoplasia. A 2-L polyethylene glycol-based purge, administered the day before the procedure, is the most widely practiced preparation regimen. Whether this regimen can be further improved (i.e., by further decreasing its volume, changing the timing of administration, coupling it with prokinetics and/or other factors) or if it can really affect the DY, is still under discussion. Faecal calprotectin has been used in SBCE studies in two settings: in patients taking non-steroidal anti-inflammatory drugs, to evaluate the type and extent of mucosal damage and, more importantly from a clinical point of view, in patients with known or suspected Crohn's disease for assessment of inflammation activity. Although there is still a lot of debate around the exact reasons of SBCE poor performance in various small-bowel segments, it is worth to remember that the capsule progress is non-steerable, hence more rapid in the proximal than in lower segments of the small-bowel. Capsule aspiration, a relatively unexpected complication, has been reported with increasing frequency. This is probably related with the increase in the mean age of patients undergoing CE. CE video review is a time-consuming procedure. Therefore, several attempts have been made to develop technical software features, in order to make CE video analysis easier and shorter (without jeopardizing its accuracy). Suspected Blood Indicator, QuickView and Fujinon Intelligent Chromo Endoscopy are some of the software tools that have been checked in various clinical studies to date.

The aim of this study was to determine the detection rate of the ampulla of Vater (AoV) during small bowel capsule endoscopy (SBCE) examinations and compare the two SBCE systems used in our center.

SBCE procedures performed in our center from March 2005 to June 2011 were reviewed retrospectively. A single reviewer, following a detailed protocol, analyzed 30 min of each recording to identify the AoV.

A total of 619 SBCE procedures were enrolled in the study, including 262 with a PillCam SB1, 148 with a PillCam SB2 and 209 with a MiroCam. AoV was identified in 59 SBCE examinations (9.5%), consisting of 28 with a PillCam SB1 (28/262, 10.7%), 13 with a PillCam SB2 (13/148, 8.8%) and 18 with a MiroCam (18/209, 8.6%) (P = 0.665). The AoV was visualized in 53.2 frames (median 12 frames, range 1-1056 frames); and the detection rate was low regardless of indication, patients' characteristics, SBCE system used or capsule transit parameters. Bile spout was associated with a higher AoV detection (P = 0.003).

The persistently low AoV detection rate using two different SBCE systems underlines the weakness of non-steerable capsule endoscopy. Furthermore, if AoV detection is taken as a surrogate marker of small polyp detection, it becomes obvious both that non-steerable SBCE cannot replace a side-viewing endoscope in the evaluation of periampullary polyps in familial adenomatous polyposis and that it is an infallible method in other small bowel polyposis states.

Wireless capsule endoscopy (WCE) is a device that allows the direct visualization of gastrointestinal tract with minimal discomfort for the patient, but at the price of a large amount of time for screening. In order to reduce this time, several works have proposed to automatically remove all the frames showing intestinal content. These methods label frames as {intestinal content- clear} without discriminating between types of content (with different physiological meaning) or the portion of image covered. In addition, since the presence of intestinal content has been identified as an indicator of intestinal motility, its accurate quantification can show a potential clinical relevance. In this paper, we present a method for the robust detection and segmentation of intestinal content in WCE images, together with its further discrimination between turbid liquid and bubbles. Our proposal is based on a twofold system. First, frames presenting intestinal content are detected by a support vector machine classifier using color and textural information. Second, intestinal content frames are segmented into {turbid, bubbles, and clear} regions. We show a detailed validation using a large dataset. Our system outperforms previous methods and, for the first time, discriminates between turbid from bubbles media.

Prior work has shown that videocapsule endoscopy image features are a useful tool for quantitatively distinguishing the intestinal mucosal surface of untreated celiac patients from that of controls. The use of dynamic estimates of wall motility may further help to improve classification.

Videocapsule endoscopy clips (200 frames each, 2 frames/s, 576 × 576 pixels/frame) were acquired at five small intestinal locations in 11 untreated celiac patients (celiacs) and ten controls. Color images were converted to grayscale and analyzed frame-by-frame. Variations in the position and width of the center of the small intestinal lumen were quantitatively estimated. The darkest grayscale pixels were used as an estimate of the lumen center. Over 200 frames, the standard deviation of the lumen center xy position and the mean and standard deviation in lumen center width were used as dynamic estimates of wall motility. These parameters were plotted in three-dimensional space, and the best discriminant function was used to classify celiacs versus controls at each of the following five locations: (1) duodenal bulb, (2) distal duodenum, (3) jejunum, (4) ileum, and (5) distal ileum.

The overall sensitivity for the classification of celiacs versus controls at all five locations was 98.2 %, while the specificity was 96.0 %. From location 1 to 5, there was a tendency for the lumen center width to diminish in terms of frame-to-frame variability by 7.6 % in celiacs (r (2) = 0.4) and 9.7 % in controls (r (2) = 0.7).

In addition to examining the mucosal surface, videocapsule endoscopy can assess small bowel intestinal motility and aid in distinguishing celiac patients from controls.

Videocapsule endoscopy can be useful to detect small intestinal pathology in celiac disease patients. However, presence of extraneous features including air bubbles and opaque fluids can complicate the analysis. A technique for quantitative analysis of videocapsule images is presented that is robust to presence of extraneous features.

Videocapsule clips were acquired from five small intestinal locations in 12 celiacs with villous atrophy and 11 control patients. Clips were 200 frames in length, their resolution was 576 × 576 pixels and 256 grayscale levels, with 2/s frame rate. The dominant period (DP), defined as the tallest peak in the ensemble average power spectrum, was computed over each clip without removal of extraneous features. Ensemble average basis images were constructed, and measurements were made of their frame-to-frame variation in brightness and texture.

From pooled basis images, celiac images had greater texture than controls and exhibited more brightness variation (p<0.05 in mean and p<0.01 in standard deviation). In celiacs, correlation existed between greater textural alterations versus longer DP (r²=0.47), and between greater brightness variation and longer DP (r²=0.33). There was no significant correlation between quantitative features and DP in controls (r²<0.25).

Using this new method, celiac videoclips were quantitatively distinguishable from control videoclips without manual or computer-assisted detection, masking, and removal of extraneous image features. Furthermore, in celiac but not control basis images, larger textural and brightness alterations were correlated to longer DP. Greater textural and brightness alterations, and thus longer periodicities, are likely related to presence of villous atrophy.

The gastrointestinal tract is home to some of the most deadly human diseases. Exacerbating the problem is the difficulty of accessing it for diagnosis or intervention and the concomitant patient discomfort. Flexible endoscopy has established itself as the method of choice and its diagnostic accuracy is high, but there remain technical limitations in modern scopes, and the procedure is poorly tolerated by patients, leading to low rates of compliance with screening guidelines. Although advancement in clinical endoscope design has been slow in recent years, a critical mass of enabling technologies is now paving the way for the next generation of gastrointestinal endoscopes. This review describes current endoscopes and provides an overview of innovative flexible scopes and wireless capsules that can enable painless endoscopy and/or enhanced diagnostic and therapeutic capabilities. We provide a perspective on the potential of these new technologies to address the limitations of current endoscopes in mass cancer screening and other contexts and thus to save many lives.

Despite being considered the most effective method for colorectal cancer diagnosis, colonoscopy take-up as a mass-screening procedure is limited mainly due to invasiveness, patient discomfort, fear of pain, and the need for sedation. In an effort to mitigate some of the disadvantages associated with colonoscopy, this work provides a preliminary assessment of a novel endoscopic device consisting in a softly tethered capsule for painless colonoscopy under robotic magnetic steering.

The proposed platform consists of the endoscopic device, a robotic unit, and a control box. In contrast to the traditional insertion method (i.e., pushing from behind), a "front-wheel" propulsion approach is proposed. A compliant tether connecting the device to an external box is used to provide insufflation, passing a flexible operative tool, enabling lens cleaning, and operating the vision module. To assess the diagnostic and treatment ability of the platform, 12 users were asked to find and remove artificially implanted beads as polyp surrogates in an ex vivo model. In vivo testing consisted of a qualitative study of the platform in pigs, focusing on active locomotion, diagnostic and therapeutic capabilities, safety, and usability.

The mean percentage of beads identified by each user during ex vivo trials was 85 ± 11%. All the identified beads were removed successfully using the polypectomy loop. The mean completion time for accomplishing the entire procedure was 678 ± 179 s. No immediate mucosal damage, acute complications such as perforation, or delayed adverse consequences were observed following application of the proposed method in vivo.

Use of the proposed platform in ex vivo and preliminary animal studies indicates that it is safe and operates effectively in a manner similar to a standard colonoscope. These studies served to demonstrate the platform's added advantages of reduced size, front-wheel drive strategy, and robotic control over locomotion and orientation.

Lesions missed by capsule endoscopy (CE) have been reported and this may be partly because of the properties of the capsule. We aimed to compare the ability of Pillcam SB1, SB2, ESO1 and ESO2 to identify the ampulla of Vater (AoV).

Patients were divided into four groups: SB1 [single head capsule, 2 frames per second (fps), a 140° field of view, n=50], SB2 (single head, 2 fps, a wider field of view of 156°, n=50), ESO1 (double head, 14 fps, a 140° field of view, n=8) and ESO2 (double head, 18 fps, an extra wide field of view of 169°, n=12). Metoclopramide was administered in 25 out of 50 patients in SB1 group and all patients in SB2 group before CE.

The AoV was not detected in any patients having SB1, irrespective of the use of metoclopramide. The AoV was identified in only nine out of 50 (18%) patients in the SB2 group confirming the benefit of a widened field of view, however, showed that even this capsule failed to visualize the AoV in more than three-quarters of cases. Double-headed capsules with faster frame rates did not improve the detection rate, the AoV was visualized in only one out of 12 (8%) patients in the ESO2 group but none in the ESO1 studies.

Currently, CE is not reliable to visualize the AoV and by inference the proximal duodenum. This is most likely related to the speed at which the capsule passes through the fixed second part of the duodenum. Faster frame rates plus a wider field of view do not overcome this limitation, which could account for missed lesions elsewhere in the small bowel.