Artificial intelligence in detection of small bowel lesions and their bleeding risk:A new step forward

The present letter to the editor is related to the study with the title“Automatic detection of small bowel(SB)lesions with different bleeding risk based on deep learning models”.Capsule endoscopy(CE)is the main tool to assess SB diseases but it is a time-consuming procedure with a significant error rate.The development of artificial intelligence(AI)in CE could simplify physicians’tasks.The novel deep learning model by Zhang et al seems to be able to identify various SB lesions and their bleeding risk,and it could pave the way to next perspective studies to better enhance the diagnostic support of AI in the detection of different types of SB lesions in clinical practice.

Immune signature of small bowel adenocarcinoma and the role of tumor microenvironment

In this editorial we comment on the article published“Clinical significance of programmed cell death-ligand expression in small bowel adenocarcinoma is determined by the tumor microenvironment”.Small bowel adenocarcinoma(SBA)is a rare gastrointestinal neoplasm and despite the small intestine's significant surface area,SBA accounts for less than 3%of such tumors.Early detection is challenging and the reason arises from its asymptomatic nature,often leading to late-stage discovery and poor prognosis.Treatment involves platinum-based chemotherapy with a 5-fluorouracil combination,but the lack of effective chemotherapy contributes to a generally poor prognosis.SBAs are linked to genetic disorders and risk factors,including chronic inflammatory conditions.The unique characteristics of the small bowel,such as rapid cell renewal and an active immune system,contributes to the rarity of these tumors as well as the high intratumoral infiltration of immune cells is associated with a favorable prognosis.Programmed cell death-ligand 1(PD-L1)expression varies across different cancers,with potential discrepancies in its prognostic value.Microsatellite instability(MSI)in SBA is associated with a high tumor mutational burden,affecting the prognosis and response to immunotherapy.The presence of PD-L1 and programmed cell death 1,along with tumor-infiltrating lymphocytes,plays a crucial role in the complex microenvironment of SBA and contributes to a more favorable prognosis,especially in the context of high MSI tumors.Stromal tumor-infiltrating lymphocytes are identified as independent prognostic indicators and the association between MSI status and a favorable prognosis,emphasizes the importance of evaluating the immune status of tumors for treatment decisions.

Intestinal tuberculosis with small bowel stricture and hemorrhage as the predominant manifestation: Three case reports

BACKGROUND Intestinal tuberculosis is a chronic disease caused by Mycobacterium tuberculosis that mainly affects the ileum and cecum.Small bowel tuberculosis,characterized by predominant involvement of the small intestine,is an extremely rare condition with highly atypical clinical presentations,making diagnosis even more challenging.CASE SUMMARY We report three cases of small intestinal tuberculosis,two of the patients pre-sented primarily with abdominal pain,and one presented with gastrointestinal bleeding.All patients underwent blood tests and imaging examinations.Small bowel endoscopy(SBE)revealed that the main lesions in these patients were in-testinal stenosis or gastrointestinal bleeding caused by small intestinal ulcers.One patient ultimately underwent surgical treatment.Following a complex diagnostic process and comprehensive analysis,all patients were confirmed to have small intestinal tuberculosis and received standard antituberculosis treatment,leading to an improvement in their condition.CONCLUSION Patients with SBTs present with nonspecific symptoms such as abdominal pain,weight loss,and occasional gastrointestinal bleeding.Accurate diagnosis requires a thorough evaluation of clinical symptoms and various tests to avoid misdiagno-sis and complications.

A prospective randomized trial of transnasal ileus tube vs nasogastric tube for adhesive small bowel obstruction

AIM:To study the therapeutic efficacy of a new transnasal ileus tube advanced endoscopically for adhesive small bowel obstruction.METHODS:A total of 186 patients with adhesive small bowel obstruction treated from September 2007 to February 2011 were enrolled into this prospective randomized controlled study.The endoscopically advanced new ileus tube was used for gastrointestinal decompression in 96 patients and ordinary nasogastric tube(NGT) was used in 90 patients.The therapeutic efficacy was compared between the two groups.RESULTS:Compared with the NGT group,the ileus tube group experienced significantly shorter time for relief of clinical symptoms and improvement in the findings of abdominal radiograph(4.1 ± 2.3 d vs 8.5 ± 5.0 d) and laboratory tests(P < 0.01).The overall effectiveness rate was up to 89.6% in the ileus tube group and 46.7% in the NGT group(P < 0.01).And 10.4% of the patients in the ileus tube group and 53.3% of the NGT group underwent surgery.For recurrent adhesive bowel obstruction,ileus tube was also significantly more effective than NGT(95.8% vs 31.6%).In the ileus tube group,the drainage output on the first day and the length of hospital stay were significantly different depending on the treatment success or failure(P < 0.05).The abdominal radiographic improvement was correlated with whether or not the patient underwent surgery.CONCLUSION:Ileus tube can be used for adhesive small bowel obstruction.Endoscopic placement of the ileus tube is convenient and worthy to be promoted despite the potential risks.

Decompression of the small bowel by endoscopic long-tube placement

AIM:To investigate and compare the decompression effect on small bowel obstruction of a long tube inserted using either endoscopic or fluoroscopic placement.METHODS:Seventy-eight patients with small bowel obstruction requiring decompression were enrolled in the study and divided into two groups.Intubation of a long tube was guided by fluoroscopy in one group and by endoscopy in the other.The duration of the procedure and the success rate for each group were evaluated.RESULTS:A statistically significant difference in the mean duration of the procedure was found between the fluoroscopic group(32.6±14.6 min)and the endoscopic group(16.5±7.8 min)among the cases classified as successful(P<0.05).The success rate was significantly different between the groups:88.6%in the fluoroscopic group and 100%in the endoscopic group(P <0.05).CONCLUSION:For patients with adhesive small bowel obstruction,long-tube decompression is recommended and long-tube insertion by endoscopy was superior to fluoroscopic placement.

Surgically treated primary malignant tumor of small bowel:A clinical analysis

AIM:To evaluate the clinical presentation,treatment and survival of patients with primary malignant tumor of small bowel(PMTSB).METHODS:Clinicopathologic data about 141 surgically treated PMTSB patients(91 males and 50 females) at the median age of 53.5 years(range 23-79 years) were retrospectively analyzed.RESULTS:The most common initial clinical features of the patients were intermittent abdominal discomfort or vague abdominal pain(67.4%),abdominal mass(31.2%),bowel obstruction(24.1%),hemotochezia(21.3%),jaundice(16.3%),fever(14.2%),coexistence of bowel perforation and peritonitis(5.7%),coexistence of gastrointestinal bleeding and shock(5.0%),and intraabdominal bleeding(1.4%).Ileum was the most common site of tumor(44.7%),followed by jejunum(30.5%)and duodenum(24.8%).PMTSB had a nonspecific clinical presentation.Segmental bowel resection(n=81)was the most common surgical procedure,followed by right hemicolectomy(n=15),pancreaticoduodenectomy(n=10),and others(n=19).Twenty-seven adenocarcinoma patients and 13 malignant lymphoma patients received adjuvant chemotherapy with 5-fluorouracil and cyclophosphamide,adriamycin,vincristine and prednisone,respectively.Information about 120 patients was obtained during the follow-up.The median survival time of PMTSB patients was 20.3 mo.The 1-,3-and 5-year survival rate was 75.0%(90/120),40.0%(48/120)and 20.8%(25/120),respectively.Adenocarcinoma was found in 73.7%(42/57),21.1%(12/57)and 15.8%(9/57)of the patients,respec-tively.Gastrointestinal stromal tumor was observed in 80.0%(20/25),72.0%(18/25)and 36.0%(9/25)of the patients,respectively.Carcinoid was detected in 100.0%(15/15),80.0%(12/15)and 46.7%(7/15)of the patients,respectively.Malignant lymphoma was demonstrated in 69.2%(9/13),30.8%(4/13)and 0%(0/13)of the patients,respectively.CONCLUSION:En bloc resection is the principal therapy for most PMTSB and chemotherapy is the important treatment modality for malignant lymphoma and other malignant tumors of small bowel which cannot be radically removed.

Eosinophilic gastroenteritis presenting as small bowel obstruction: A case report and review of the literature

Eosinophilic gastroenteritis is a rare disease of unknown etiology. It is characterized by eosinophilic infiltration of the bowel wall to a variable depth and symptoms associated with gastrointestinal tract. Recently, the authors experienced a case of eosinophilic gastroenteritis presenting as small bowel obstruction. A 51-year old woman was admitted to our hospital complaining of abdominal pain and vomiting. Physical examination revealed a distended abdomen with diffuse tenderness. Complete blood count showed mild leukocytosis without eosinophilia. Computed tomography confirmed a dilatation of the small intestine with ascites. An emergency laparotomy was performed for a diagnosis of peritonitis due to intestinal obstruction. Segmental resection of the ileum and end to end anastomosis were performed. Histologically, there was a dense infiltration of eosinophils throughout the entire thickness of ileal wall and eosinophilic enteritis was diagnosed. The patient recovered well, and was free from gastrointestinal symptoms at the time when we reported her disease.

Lymphangioma of the small bowel mesentery: A case report and review of the literature

Lymphangioma is a rare benign condition characterized by proliferation of lymphatic spaces. It is usually found in the head and neck of affected children. Lymphangioma of the small-bowel mesentery is rare, having been reported for less than 1% of all lymphangiomas. Importantly, it can cause fatal complications such as volvulus or involvement of the main branch of the mesenteric arteries, requiring emergency surgery. Moreover, the gross and histopathologic findings may resemble benign multicystic mesothelioma and lymphangiomyoma. Immunohistochemical study for factor Ⅷ-related antigen, D2-40, calretinin and human melanoma black-45 (HMB-45) are essential for diagnosis. Factor Ⅷ-related antigen and D2-40 are positive in lymphangioma but negative in benign multicystic mesothelioma. HMB-45 shows positive study in the smooth-muscle cells around the lymphatic spaces of the lymphangiomyoma. We report a case of smallbowel volvulus induced by mesenteric lymphangioma in a 2-year-and-9-mo-old boy who presented with rapid abdominal distension and vomiting. The abdominal computed tomography scan showed a multiseptated mass at the right lower quadrant with a whirllike small-bowel dilatation, suggestive of a mesenteric cyst with midgut volvulus. The intraoperative findings revealed a huge, lobulated, yellowish pink, cystic mass measuring 20 cm × 20 cm × 10 cm, that was originated from the small bowel mesentery with small-bowel volvulus and small-bowel dilatation. Cut surface of the mass revealed multicystic spaces containing a milky white fluid. The patient underwent tumor removal with small-bowel resection and end-to-end anastomosis. Microscopic examination revealed that the cystic walls were lined with flat endothelial cells and comprised of smooth muscle in the walls. The flat endothelial cells were positive for factor Ⅷ-related antigen and D2-40 but negative for calretinin. HMB-45 showed negative study in the smooth-muscle cells around the lymphatic spaces. Thus, the diagnosis was lymphangioma of the small bowel mesentery with associated small bowel volvulus.

Role of small bowel capsule endoscopy in the diagnosis and management of iron deficiency anemia in elderly: A comprehensive review of the current literature

Iron deficiency anemia(IDA)is common and often under recognized problem in the elderly.It may be the result of multiple factors including a bleeding lesion in the gastrointestinal tract.Twenty percent of elderly patients with IDA have a negative upper and lower endoscopy and two-thirds of these have a lesion in the small bowel(SB).Capsule endoscopy(CE)provides direct visualization of entire SB mucosa,which was not possible before.It is superior to push enteroscopy,enteroclysis and barium radiography for diagnosing clinically significant SB pathology resulting in IDA.Angioectasia is one of the commonest lesions seen on the CE in elderly with IDA.The diagnostic yield of CE for IDA progressively increases with advancing age,and is highest among patients over 85 years of age.Balloon assisted enteroscopy is used to treat the lesions seen on CE.CE has some limitations mainly lack of therapeutic capability,inability to provide precise location of the lesion and false positive results.Overall CE is a very safe and effective procedure for the evaluation of IDA in elderly.

Implications of small-bowel transit time in the detection rate of capsule endoscopy: A multivariable multicenter study of patients with obscure gastrointestinal bleeding

AIMTo define the role of small-bowel transit time in the detection rate of significant small-bowel lesions.METHODSSmall-bowel capsule endoscopy records, prospectively collected from 30 participating centers in the Lombardy Registry from October 2011 to December 2013, were included in the study if the clinical indication was obscure gastrointestinal bleeding and the capsule reached the cecum. Based on capsule findings, we created two groups: P2 (significant findings) and P0-1 (normal/negligible findings). Groups were compared for age, gender, small-bowel transit time, type of instrument, modality of capsule performance (outpatients vs inpatients), bowel cleanliness, and center volume.RESULTSWe retrieved and scrutinized 1,433 out of 2,295 capsule endoscopy records (62.4%) fulfilling the inclusion criteria. Patients were 67 &#x000b1; 15 years old, and 815 (57%) were males. In comparison with patients in the P0-1 group, those in the P2 group (n = 776, 54%) were older (P &#x0003c; 0.0001), had a longer small-bowel transit time (P = 0.0015), and were more frequently examined in low-volume centers (P &#x0003c; 0.001). Age and small-bowel transit time were correlated (P &#x0003c; 0.001), with age as the sole independent predictor on multivariable analysis. Findings of the P2 group were artero-venous malformations (54.5%), inflammatory (23.6%) and protruding (10.4%) lesions, and luminal blood (11.5%).CONCLUSIONIn this selected, prospectively collected cohort of small-bowel capsule endoscopy performed for obscure gastrointestinal bleeding, a longer small-bowel transit time was associated with a higher detection rate of significant lesions, along with age and a low center volume, with age serving as an independent predictor.

Biomarkers for radiation-induced small bowel epithelial damage:An emerging role for plasma Citrulline

Reduction of cancer treatment-induced mucosal injury has been recognized as an important target for improving the therapeutic ratio as well as reducing the economic burden associated with these treatment related sequellae. Clinical studies addressing this issue are hampered by the fact that specif ic objective parameters, which enable monitoring of damage in routine clinical practice, are lacking. This review summarizes pros and cons of currently available endpoints for intestinal injury. The metabolic background and characteristics of plasma citrulline, a recently investigated biomarker specifically for small intestinal injury, are discussed in more detail.

Experimental small bowel preservation using Polysol: A new alternative to University of Wisconsin solution, Celsior and histidine-tryptophan-ketoglutarate solution?

AIM: To evaluate the potential of Polysol, a newly developed preservation solution, in cold storage of small bowel grafts, compared with the current standards, University of Wisconsin solution (UW), Celsior and histidine-tryptophan-ketoglutarate solution (HTK). METHODS: Male Wistar rats were used as donors. Small bowels were retrieved, flushed and then stored in the respective 4 solutions for 18 h at 4℃. Functional integrity of the grafts was evaluated by isolated reperfusion with oxygenated Krebs-Henseleit buffer at 37℃ for 30 min in all 4 groups. RESULTS: Polysol preservation exhibited the highest tissue ATP concentration and the lowest release of LDH. Malondialdehyde, an index for tissue lipid peroxidation, was also the lowest in Polysol. Tissue oxygen consumption was significantly higher in Polysol than in the others. Of interest, UW-storage promoted 10-fold higher apoptosis than in the others. Moreover, electron microscopy revealed that the mucosal villi/micro-villi formation and the cell organelles, including mitochondria, were both significantly better preserved in Polysol, while deleterious alterations were apparent in the others, most notably in UW. Although Celsior and HTK exhibited the better trend of results than UW in some parameters, but could not reach the over-all superiority to UW.CONCLUSION: Cold storage using Polysol resulted in significantly better integrity and function of small bowel grafts than UW. Hence, Polysol may be a novel alternative for the small bowel preservation.

OMOM capsule endoscopy in diagnosis of small bowel disease

Objective： To assess the diagnostic efficiency of OMOM capsule endoscopy （CE） in a group of patients with different indications. Methods： Data from 89 consecutive patients （49 males, 40 females） with suspected small bowel disease who underwent OMOM CE （Jinshan Science and Technology Company, review. The patients＇ indications of the disease consisted of the Chongqing, China） examination were obtained by retrospective following： obscure gastrointestinal bleeding （OGIB）, abdominal pain or diarrhea, partial intestinal obstruction, suspected inflammatory bowel disease, tumor of unknown origin, hypoproteinemia, constipation, weight loss, and elevated tumor markers. Results： CE failed in one patient. Visualization of the entire small bowel was achieved in 75.0%. Capsules were naturally excreted by all patients. The detection rate of abnormalities was 70.5% for patients with suspected small bowel disease, and the diagnostic yield for patients with OGIB was higher than that for patients with abdominal pain or diarrhea （85.7% vs 53.3%, P〈0.005）. Angiodysplasia was the most common small bowel finding. Active bleeding sites were noted in the small intestine in 11 cases. Conclusion： OMOM CE is a useful diagnostic tool for the diagnosis of variably suspected small bowel disease, whose diagnostic efficiency is similar to that of the Pillcam SB （small bowel） CE （Given Imaging, Yoqneam, Israel）.

Multi-detector CT enterography with iso-osmotic mannitol as oral contrast for detecting small bowel disease

AIM: To assess the feasibility and usefulness of multi-detector CT enterography with orally administered iso-osmotic mannitol as negative contrast in demonstrating small bowel disease.METHODS: Thirteen volunteers and 38 patients with various kinds of small bowel disease were examined. We administered about 1 500 mL iso-osmotic mannitol as negative contrast agent and then proceeded with helical CT scanning on a Siemens Sensation 16 scanner. All volunteers and patients were interviewed about their tolerance of the procedure. Two radiologists postprocessed imaging data with MPR, thin MIP, VRT and INSPACE when necessary and then interpreted the scans,and adequacy of luminal distention was evaluated on a four-point scale. Demonstration of features of various kinds of small bowel disease was analyzed.RESULTS: The taste of iso-osmotic mannitol is good (slightly sweet) and acceptable by all. Small bowel distention was excellent and moderate in most volunteers and patients. CT features of many kinds of diseases such as tumors, Crohn's disease,and small bowel obstruction,etc. were clearly displayed.CONCLUSION: Multi-detector CT enterography with iso-osmotic mannitol as negative contrast to distend the small bowel is a simple, rapid, noninvasive and effective method of evaluating small bowel disease.

Diagnostic yield of small bowel capsule endoscopy depends on the small bowel transit time

AIM： To investigate whether the small bowel transit time （SBTT） influences the diagnostic yield of capsule endoscopy （CE）. METHODS： Six hundred and ninety-one consecutive CE procedures collected in a database were analyzed. SBTT and CE findings were recorded. A running mean for the SBl-I- was calculated and correlated to the diagnostic yield with a Spearman＇s correlation test. Subgroup anal- yses were performed for the various indications for the procedure. RESULTS： There was a positive correlation between the diagnostic yield and SBT1- （Spearman＇s rho 0.58, P 〈 0.01）. Positive correlations between diagnostic yield and SB-FI-were found for the indication obscure gastro- intestinal bleeding （r = 0.54, P 〈 0.01）, for polyposis and carcinoid combined （r = 0.56, P 〈 0.01） and for the other indications （r = 0.90, P 〈0.01）, but not for suspected Crohn＇s disease （r = -0.40） CONCLUSION： The diagnostic yield in small bowel capsule endoscopy is positively correlated with the small bowel transit time. This is true for all indications except for suspected Crohn＇s disease.

Interventional digital subtraction angiography for small bowel gastrointestinal stromal tumors with bleeding

AIM: To retrospectively evaluate the diagnostic efficacy of interventional digital subtraction angiography (DSA) for bleeding small bowel gastrointestinal stromal tumors (GISTs).

Double-balloon enteroscopy-assisted dilatation avoids surgery for small bowel strictures: A systematic review

AIM To evaluate the therapeutic role of double-balloon enteroscopy(DBE) in small bowel strictures and to propose a standard approach to small bowel strictures.METHODS Systematic review of studies involving DBE in patients with small bowel strictures. Only studies limited to small bowel strictures were included and those with ileo-colonic strictures were excluded. RESULTS In total 13 studies were included,in which 310 patients were dilated. The average follow-up time was 31.8 mo per patient. The complication rate was 4.8% per patient and 2.6% per dilatation. Surgery was avoided in 80% of patients. After the first dilatation,46% were treated with re-dilatation and only 17% required surgery.CONCLUSION DBE-assisted dilatation avoids surgery in 80% of patients with small bowel strictures and is safe and effective. We propose a standardized approach to small bowel strictures.

Imaging of the small bowel in Crohn's disease: A review of old and new techniques

The investigation of small bowel morphology is often mandatory in many patients with Crohn's disease. Traditional radiological techniques (small bowel enteroclysis and small bowel follow-through) have long been the only suitable methods for this purpose. In recent years, several alternative imaging techniques have been proposed. To review the most recent advances in imaging studies of the small bowel, with particular reference to their possible application in Crohn's disease, we conducted a complete review of the most important studies in which traditional and newer imaging methods were performed and compared in patients with Crohn's disease. Several radiological and endoscopic techniques are now available for the study of the small bowel; each of them is characterized by a distinct profile of favourable and unfavourable features. In some cases, they may also be used as complementary rather than alternative techniques. In everyday practice, the choice of the technique to be used stands upon its availability and a careful evaluation of diagnostic accuracy, clinical usefulness, safety and cost. The recent development ofinnovative imaging techniques has opened a new and exciting area in the exploration of the small bowel in Crohn's disease patients.

Prospective evaluation of small bowel preparation with bisacodyl and sodium phosphate for capsule endoscopy

AIM： To determine the effect of Prepacol, a combination of sodium phosphate and bisacodyl, on transit and quality of capsule endoscopy （CE）. METHODS： Fivety two consecutive patients were included in this prospective study. CE was performed following a 12 h fasting period. Twenty six patients were randomized for additional preparation with Prepacol. The quality of CE was assessed separately for the proximal and the distal small bowel by 3 experienced endoscopists on the basis of a graduation which was initially developed with 20 previous CE. RESULTS： Preparation with Prepacol accelerated small bowel transit time （262 ± 55 rain vs 287 ± 97 min）, but had no effect on the quality of CE. Visibility was significantly reduced in the distal compared to the proximal small bowel. CONCLUSION： The significantly reduced visibility of CE in the distal small bowel allocates the need for a good preparation. Since Prepacol has no beneficial effect on CE the modality of preparation and the ideal time of application remains unclear. Further standardized examinations are necessary to identify sufficient preparation procedures and to determine the impact of the volume of the preparation solution.

Video capsule endoscopy vs double-balloon enteroscopy in the diagnosis of small bowel bleeding:A systematic review and metaanalysis

AIM To compare the diagnostic accuracy of video capsule endoscopy(VCE) and double-balloon enteroscopy(DBE) in cases of obscure gastrointestinal bleeding(OGIB) of vascular origin.METHODS MEDLINE(via PubMed), LILACS(via BVS) and Cochrane/CENTRAL virtual databases were searched for studies dated before 2017. We identified prospective and retrospective studies, including observational, cohort, single-blinded and multicenter studies, comparing VCE and DBE for the diagnosis of OGIB, and data of all the vascular sources of bleeding were collected. All patients were subjected to the same gold standard method. Relevant data were then extracted from each included study using a standardized extraction form. We calculated study variables(sensitivity, specificity, prevalence, positive and negative predictive values and accuracy) and performed a meta-analysis using Meta-Disc software.RESULTS In the per-patient analysis, 17 studies(1477 lesions) were included. We identified3150 exams(1722 VCE and 1428 DBE) in 2043 patients and identified 2248 sources of bleeding, 1467 of which were from vascular lesions. Of these lesions, 864(58.5%) were diagnosed by VCE, and 613(41.5%) were diagnosed by DBE. The pretest probability for bleeding of vascular origin was 54.34%. The sensitivity of DBE was 84%(95%CI: 0.82-0.86; heterogeneity: 78.00%), and the specificity was92%(95%CI: 0.89-0.94; heterogeneity: 92.0%). For DBE, the positive likelihood ratio was 11.29(95%CI: 4.83-26.40; heterogeneity: 91.6%), and the negative likelihood ratio was 0.20(95%CI: 0.15-0.27; heterogeneity: 67.3%). Performing DBE after CE increased the diagnostic yield of vascular lesion by 7%, from 83% to90%.CONCLUSION The diagnostic accuracy of detecting small bowel bleeding from a vascular source is increased with the use of an isolated video capsule endoscope compared with isolated DBE. However, concomitant use increases the detection rate of the bleeding source.