Imaging techniques in IBD and their role in follow-up and surveillance

Bismuth drug-inspired ultra-small dextran coated bismuth oxide nanoparticles for targeted computed tomography imaging of inflammatory bowel disease

Bismuth (Bi)-based computed tomography (CT) imaging contrast agents (CAs) hold significant promise for diagnosing gastrointestinal diseases due to their cost-effectiveness, heightened sensitivity, and commendable biocompatibility. Nevertheless, substantial challenges persist in achieving an easy synthesis process, remarkable water solubility, and effective targeting ability for the potential clinical transformation of Bi-based CAs. Herein, we show Bi drug-inspired ultra-small dextran coated bismuth oxide nanoparticles (Bi2O3-Dex NPs) for targeted CT imaging of inflammatory bowel disease (IBD). Bi2O3-Dex NPs are synthesized through a simple alkaline precipitation reaction using bismuth salts and dextran as the template. The Bi2O3-Dex NPs exhibit ultra-small size (3.4 nm), exceptional water solubility (over 200 mg mL-1), high Bi content (19.75 %), excellent biocompatibility and demonstrate higher X-ray attenuation capacity compared to clinical iohexol. Bi2O3-Dex NPs not only enable clear visualization of the GI tract outline and intestinal loop structures in CT imaging but also specifically target and accumulate at the inflammatory site in colitis mice after oral administration, facilitating a precise diagnosis and enabling targeted CT imaging of IBD. Our study introduces a novel and clinically promising strategy for synthesizing high-performance Bi2O3-Dex NPs for diagnosing gastrointestinal diseases.

The effect of the size of gold nanoparticle contrast agents on CT imaging of the gastrointestinal tract and inflammatory bowel disease

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD). CT imaging with contrast agents is commonly used for visualizing the gastrointestinal (GI) tract in UC patients. CT is a common imaging modality for evaluating IBD, especially in patients with acute abdominal pain presenting to emergency departments. CT's major limitation lies in its lack of specificity for imaging UC, as the commonly used agents are not well-suited for inflamed areas. Recent studies gastrointestinal tract (GIT) in UC. Further systemic research is needed to explore novel contrast agents that can specifically image disease processes in this disease setting.

A Transformable Mucoadhesive Microgel Network for Noninvasive Multimodal Imaging And Radioprotection of a Large Area of the Gastrointestinal Tract

The lack of noninvasive imaging and modulation of a large area of the gastrointestinal (GI) tract constrain the diagnosis and treatment of many GI-related diseases. Recent advances use novel mucoadhesive materials to coat a part of the GI tract and then modulate its functions. High mucoadhesion is the key factor of the partial coating, but also the limitation for not spreading and covering the lower GI tract. Here, a bismuth-pectin organic-inorganic hybrid complex is screened and engineered into a transformable microgel network (Bi-GLUE) with high flowability and mucoadhesion, such that it can quickly transit through and coat a large area of the GI tract. In murine and porcine models, Bi-GLUE delivers contrast agents to achieve real-time, large-area GI-tract imaging under X-ray or magnetic resonance  modalities and to facilitate the non-invasive diagnosis of familial adenomatous polyposis. Moreover, Bi-GLUE, like an intracorporal radiation shield, decreases the radiotoxicity in a whole-abdomen irradiation rat model. This transformable microgel network offers a new direction that can modulate a large area of the GI tract and may have broad applications for GI-related conditions.

Diagnosis of ulcerative colitis and Crohn's disease using transabdominal ultrasonography

The following are some common features of ulcerative colitis (UC) and Crohn's disease (CD) on transabdominal ultrasonography (TUS). UC, which consists primarily of mucosal inflammation, is seen on TUS as wall thickening with preserved layer structure continuing from the rectum in the active phase of UC. Inflammation confined to the mucosa is seen as thickening of the mucosal/submucosal layers. When the inflammation becomes severe, the echogenicity of the submucosal layer decreases and the layer structure becomes indistinct. CD, which consists primarily of discontinuous transmural inflammation, shows more pronounced hypoechoic wall thickening than UC at the transmural inflammation. On TUS, the layer structure becomes indistinct and gradually disappears due to the depth of the myriad inflammation during the active phase of CD. It is important to evaluate the changes in wall thickening and layer structure when diagnosing UC and CD with TUS. In addition, diagnostic techniques such as color Doppler and contrast-enhanced ultrasonography, which can be used to assess blood flow, and elastography, which can be used to evaluate stiffness, are also used. Thus, TUS is a noninvasive and convenient modality that shows promise as a useful examination for diagnosis of UC and CD.

Diagnostic yield for video capsule endoscopy in gastrointestinal graft- versus -host disease: a systematic review and metaanalysis

BACKGROUND

The gastrointestinal tract is the second most involved organ for graft-versus-host disease where involvement of the small intestine is present in 50% of the cases. Therefore, the use of a non-invasive investigation i.e., video capsule endoscopy (VCE) seems ideal in the diagnostic work-up, but this has never been systematically evaluated before.

OBJECTIVE

The aim of this systematic review was to determine the efficacy and safety of VCE, in comparison with conventional endoscopy in patients who received hematopoietic stem cell transplantation.

METHOD

Databases searched were PubMed, Scopus, EMBASE, and Cochrane CENTRAL. All databases were searched from their inception date until June 17, 2022. The search identified 792 publications, of which 8 studies were included in our analysis comprising of 232 unique patients. Efficacy was calculated in comparison with the golden standard i.e., histology. Risk of bias assessment was performed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool.

RESULTS

The pooled sensitivity was higher for VCE at 0.77 (95% CI: 0.60-0.89) compared to conventional endoscopy 0.62 (95% CI: 0.47-0.75) but the difference was not statistically significant (p = 0.155, Q = 2.02). Similarly, the pooled specificity was higher for VCE at 0.68 (95% CI: 0.46-0.84) than for conventional endoscopy at 0.58 (95% CI: 0.40-0.74) but not statistically significant (p = 0.457, Q = 0.55). Moreover, concern for adverse events such as intestinal obstruction or perforation was not justified since none of the capsules were retained in the small bowel and no perforations occurred in relation to VCE. A limitation to the study is the retrospective approach seen in 50% of the studies.

CONCLUSION

The role of video capsule endoscopy in diagnosing or dismissing graft-versus-host disease is not yet established and requires further studies. However, the modality appears safe in this cohort.

How to Evaluate Fibrosis in IBD?

In this review, we will describe the importance of fibrosis in inflammatory bowel disease (IBD) by discussing its distinct impact on Crohn's disease (CD) and ulcerative colitis (UC) through their translation to histopathology. We will address the existing knowledge on the correlation between inflammation and fibrosis and the still not fully explained inflammation-independent fibrogenesis. Finally, we will compile and discuss the recent advances in the noninvasive assessment of intestinal fibrosis, including imaging and biomarkers. Based on the available data, none of the available cross-sectional imaging (CSI) techniques has proved to be capable of measuring CD fibrosis accurately, with MRE showing the most promising performance along with elastography. Very recent research with radiomics showed encouraging results, but further validation with reliable radiomic biomarkers is warranted. Despite the interesting results with micro-RNAs, further advances on the topic of fibrosis biomarkers depend on the development of robust clinical trials based on solid and validated endpoints. We conclude that it seems very likely that radiomics and AI will participate in the future non-invasive fibrosis assessment by CSI techniques in IBD. However, as of today, surgical pathology remains the gold standard for the diagnosis and quantification of intestinal fibrosis in IBD.

Targeted Computed Tomography Visualization and Healing of Inflammatory Bowel Disease by Orally Delivered Bacterial-Flagella-Inspired Polydiiododiacetylene Nanofibers

Accurate diagnosis and timely therapeutic intervention of inflammatory bowel disease (IBD) is essential in preventing the progression of the disease, although it still represents an insurmountable challenge. Here we report the design of bacterial-flagella-inspired polydiiododiacetylene (PIDA) nanofibers and its performance in targeted computed tomography (CT) imaging and on-demand therapeutic intervention of IBD. With a morphology mimicking bacterial flagella, PIDA nanofibers attach on the mucus layer of the gastrointestinal (GI) tract after oral administration, evenly distributing on the GI surface to portray the GI lining under CT scan within 2 h. PIDA can retain for a longer time in the damaged mucosa at the inflamed lesions than in normal GI tissues to enable the targeted CT visualization of IBD. PIDA also scavenges reactive oxygen species and ameliorates gut dysbiosis attributed to its iodine-substituted polydiacetylene structure, so that the enriched PIDA nanofibers at the targeted IBD lesions can alleviate the inflammation while maintaining the gut microbiota homeostasis, thus promoting the rebalance of GI microenvironment and the mucosal healing.

Radiosynthesis and in silico bioevaluation of 131 I-Sulfasalazine as a highly selective radiotracer for imaging of ulcerative colitis

This study demonstrated the tracking of ulcerative colitis, which is considered a stressful immune disease. Although there are many ways to test for this disease including dependence on gases, dyes, and painful anal endoscopy, these treatment modalities have many disadvantages. Hence, it is the utmost need of time to discover new methods to detect this chronic immune disease and to avoid the defects of traditional methodologies. Sulfasalazine (SSD) was labeled with iodine-131 (half-life: 8 days, Energy: 971 keV) under optimum reaction conditions including the amount of reducing agent, pH factor, chloramine-T (Ch-T) amount, and incubation period. Characterization was performed using ¹ H/ ¹³ C-NMR, ESI-MS, and HPLC (UV/ Radio) techniques. The biodistribution study was performed in normal and ulcerative mice models, and in silico molecular docking study was performed to evaluate the possible mechanism of action to target peroxisome proliferator-activated receptor gamma (PPARγ). The high radiolabeling yield of [¹³¹ I]-sulfasalazine ([¹³¹ I]-SSD) was achieved ≥90% through the direct labeling method with radioactive iodine-131 in the presence of chloramine-T (100 μg). The radiotracer [¹³¹ I]-SSD was observed to be stable in normal saline and freshly eluted serum up to 12 hr at ambient temperature (37℃ ± 2℃). The radiotracer [¹³¹ I]-SSD showed the highest uptake in the targeted organ (i.e., ulcerative colon) which was observed to be ≥75% injected dose per gram (% ID/g) organ for 24 hr postinjection (p.i). Furthermore, in silico data collected from molecular modeling analysis of SSD and [¹³¹ I]-SSD with antimicrobial protein (PDB code: 3KEG) and peroxisome proliferator-activated receptor gamma (PPARγ) (PDB code: 4XTA) showed azoreductase activity and high binding potential for PPAR-γ site, respectively. The results of biological studies obtained in this study enlighten the usefulness of radiotracer [¹³¹ I]-SSD as a potential imaging agent for ulcerative colitis.

Recent Progress in the Diagnosis and Precise Nanocarrier-Mediated Therapy of Inflammatory Bowel Disease

The effective colon drug delivery remains to be an international frontier research in inflammatory bowel disease (IBD) therapy. The exploration and research of nanocarrier-based nanomedicine with great potential brings new opportunities for IBD therapy and diagnoses. Functional nanocarriers with varying morphology and characteristics can not only effectively avoid the destruction of the complex gastrointestinal (GI) tract microenvironment but also endow drugs with target therapy and improved bioavailability, thus elevating therapeutic efficacy. In this review, we illustrated several challenges in IBD therapy, then emphasis on some latest research progress of nanoparticles based therapy of oral administration, rectal administration and parenteral administration, as well as IBD diagnoses. Finally, we described the future perspective of nanocarriers in the treatment and diagnoses of IBD.

Dextran-Coated Cerium Oxide Nanoparticles: A Computed Tomography Contrast Agent for Imaging the Gastrointestinal Tract and Inflammatory Bowel Disease

Computed tomography (CT) is an X-ray-based medical imaging technique commonly used for noninvasive gastrointestinal tract (GIT) imaging. Iodine- and barium-based CT contrast agents are used in the clinic for GIT imaging; however, inflammatory bowel disease (IBD) imaging is challenging since iodinated and barium-based CT agents are not specific for sites of inflammation. Cerium oxide nanoparticles (CeNP) can produce strong X-ray attenuation due to cerium's k-edge at 40.4 keV but have not yet been explored for CT imaging. In addition, we hypothesized that the use of dextran as a coating material on cerium oxide nanoparticles would encourage accumulation in IBD inflammation sites in a similar fashion to other inflammatory diseases. In this study, therefore, we sought to develop a CT contrast agent, i.e., dextran-coated cerium oxide nanoparticles (Dex-CeNP) for GIT imaging with IBD. We synthesized Dex-CeNP, characterized them using various analytical tools, and examined their in vitro biocompatibility, CT contrast generation, and protective effect against oxidative stress. In vivo CT imaging was done with both healthy mice and a dextran sodium sulfate induced colitis mouse model. Dex-CeNP's CT contrast generation and accumulation in inflammation sites were compared with iopamidol, an FDA approved CT contrast agent. Dex-CeNP was found to be protective against oxidative damage. Dex-CeNP produced strong CT contrast and accumulated in the colitis area of large intestines. In addition, >97% of oral doses were cleared from the body within 24 h. Therefore, Dex-CeNP can be used as a potential CT contrast agent for imaging GIT with IBD while protecting against oxidative damage.

Utilization of Diagnostic Imaging and Ionizing Radiation Exposure-Has the Tide Already Turned?

Inflammatory bowel diseases require repetitive abdominal imaging for diagnosis, follow-up, or management of complications. This editorial comments on the large incident-based case-control study on utilization of diagnostic imaging and ionizing radiation exposure by Nguyen and colleagues published in this issue.

Increased Postoperative Use of Computed Tomography Following Emergency Surgery for Ileocaecal Crohn Disease

INTRODUCTION

Multiple imaging modalities are often required for the relapsing nature of Crohn disease (CD). Computed tomography (CT) offers a rapid acquisition of images and shows high specificity and sensitivity. However, CT imaging exposes to a higher dose of ionizing radiation than other abdominal imaging modalities. The aim of this study was to compare the use of preoperative and postoperative CT scan in patients undergoing emergency and elective surgery for CD.

METHODS

All patients undergoing emergency and elective surgery for ileocaecal CD January 2014 to December 2018 were included in this prospective observational study. The study objective was to evaluate the frequency of use of CT scan perioperatively with the number and findings of preoperative and postoperative CT being the primary outcomes. The secondary outcomes were operating time, length of hospital stay, reoperations, and rehospitalization.

RESULTS

A total of 75 patients were included, 33 in the emergency group (43%) and 44 in the elective group (57%). There was a higher use of preoperative CT scan in the emergency surgery group, with 14 patients (42%) having a CT scan before surgery compared with 2 (5%) in the elective group (P=0.14). Thirteen patients (39.4%) had a postoperative CT scan in the emergency surgery group, compared with 10 patients (23.8%) in the elective surgery group.

CONCLUSION

Patients undergoing emergency surgery for CD are at increased risk of exposure to ionizing radiations due to high perioperative use of CT scan.

"Can Magnetic Resonance Enterography (MRE) replace ileo-colonoscopy for evaluating disease activity in Crohn's disease?"

Crohn's disease is a form of chronic inflammatory bowel disease that can lead to structural bowel damage due to transmural inflammation. Ileo-colonosocopy is currently essential for initial diagnosis. Reassessment of disease burden is frequently needed during episodes of active disease and when evaluating treatment efficacy. This review compares the role of Magnetic Resonance Enterography (MRE) and ileocolonoscopy in Crohn's disease management and whether cross-sectional imaging can replace invasive endoscopic tests. MRE can give information on the small bowel not visible at ileo-colonoscopy, and on extra-luminal complications. Evaluation of the bowel by MRE allows assessment of the submucosa and serosa, and thus transmural healing. MRE offers a well tolerated investigation and additional information on disease activity to better manage patients with Crohn's disease. Increasingly, there are a range of newer techniques such as diffusion weighted imaging, magnetisation transfer and motility MRI which provide greater information on fibrosis and predictors to treatment response which has been lacking despite the use of ileo-colonoscopy for several decades.

In vivo redox imaging of dextran sodium sulfate-induced colitis in mice using Overhauser-enhanced magnetic resonance imaging

In ulcerative colitis, an inflammatory bowel disease of unknown cause, diagnosis of the degree and location of colitis at an early stage is required to control the symptoms. Changes in redox status, including the production of reactive oxygen and nitrogen species (RONS), have been associated with ulcerative colitis in humans and dextran sodium sulfate (DSS)-induced colitis in rodents. In this study, the in vivo redox status of colons of DSS-induced colitis mice were monitored by Overhauser-enhanced magnetic resonance imaging (OMRI), and the relationship between redox status and colitis development was investigated. Colitis was induced by administering 5% DSS in drinking water to male Slc:ICR mice, which are a strain classified as closed colony outbred mice (5-week-old, 25-30 g). On the 3rd day of the DSS challenge, when no symptoms of colitis were displayed, the contrast decays of ¹⁵N-CmP and ¹⁴N-CxP tended to show enhancement in the whole colon and were not altered by DMSO. On the 5th day of the DSS challenge, with histological damage of the rectum being displayed, the contrast decay of ¹⁵N-CmP was significantly enhanced not only in the rectum, but also in the proximal colon, and this was suppressed by DMSO. On the 7th day of the DSS challenge, with the mice displaying severe colitis symptoms, the image contrasts of ¹⁵N-labeled 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (¹⁵N-CmP) and ¹⁴N-labeled 3-carboxyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (¹⁴N-CxP) showed much faster decay than those of healthy mice, while the increased decays of both probes were restored by the membrane-permeable reactive oxygen species (ROS) scavenger dimethyl sulfoxide (DMSO). Image differencing between the decay rate images of ¹⁵N-CmP and ¹⁴N-CxP showed the DSS-induced redox imbalance spreading over the whole colon, and a histogram of the difference image showed a smaller peak and broader distribution with the DSS treatment. These data indicate that ROS are produced intracellularly in the distal and proximal colon in the initiation stage of DSS-induced colitis, and that ROS are produced intracellularly and extracellularly in the advanced stage of DSS-induced colitis.

Single-Chain Variable Fragment Antibody of Vascular Cell Adhesion Molecule 1 as a Molecular Imaging Probe for Colitis Model Rabbit Investigation

Vascular cell adhesion molecule-1 (VCAM-1) can be a promising target for colitis study because of its critical role in inflammation development. Single-chain variable fragment (scFv) antibody presents fast blood clearance when served as an imaging probe. We applied the probe of ^99mTc-scFv-VCAM-1 to colitis rabbit to examine its imaging performance. The colitis model rabbit was prepared, and a typical inflammatory lesion was confirmed in the colon. The probe of ^99mTc-scFv-VCAM-1 was synthesized and injected into the model animal before imaging examination. Scintigraphy detected colitis lesions in both SPECT planar and SPECT/CT fused images, with higher target-to-nontarget ratios in the model group (2.71 ± 0.31) than those in the control group (1.12 ± 0.10). Biodistribution study determined tracer uptake in different organs, and autoradiography (ARG) confirmed probe accumulation in colon lesions. The uptake ratio of the model colon to the control colon was 4.71 ± 0.61 in quantitative analysis of the ARG regions of interest. Stronger VCAM-1 expression in the model colon than that in the control colon was confirmed by western blotting and immunohistochemistry. Our imaging study indicates molecular imaging with scFv-VCAM-1 as a promising way for inflammatory bowel disease diagnosis and evaluation.

Advances in Imaging Specific Mediators of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is characterized by chronic remitting and relapsing inflammation of the lower gastrointestinal tract. The etiology underlying IBD remains unknown, but it is thought to involve a hypersensitive immune response to environmental antigens, including the microbiota. Diagnosis and monitoring of IBD is heavily reliant on endoscopy, which is invasive and does not provide information regarding specific mediators. This review describes recent developments in imaging of IBD with a focus on positron emission tomography (PET) and single-photon emission computed tomography (SPECT) of inflammatory mediators, and how these developments may be applied to the microbiota.

Imaging of the Postoperative Colon

Recognition of postoperative complications is important for the immediate diagnosis and treatment needed for appropriate patient care. Identification of postoperative complications from colon surgery requires not only knowledge of the type of procedure, but also the expected normal postoperative appearance. The purpose of this article is to discuss and review the expected anatomic changes after colorectal surgery, and the appearance of the most common postoperative complications.

New cross-sectional imaging in IBD

PURPOSE OF REVIEW

Cross-sectional imaging, namely ultrasound, CT and MR enterography, complements clinical and endoscopic monitoring of activity and complications in IBD, and emerging new radiological technologies may have clinical applications in the near future. This review offers an update on the potential role of these new imaging methods in the management of IBD.

RECENT FINDINGS

Specific MR techniques [diffusion-weighted imaging (DWI), diffusion kurtosis imaging (DKI) and magnetization transfer] allow accurate detection of inflammation (DWI and maybe DKI) and fibrosis (magnetization transfer) in Crohn's disease, without the need of intravenous gadolinium administration. ultrasonography developments (elastography, contrast-enhanced ultrasonography, small intestine contrast ultrasonography and multispectral optoacoustic tomography) are promising techniques for evaluation of fibrosis (elastography) and inflammation (contrast ultrasonography). Dose-reduction techniques in CT allow similar quality imaging and diagnostic accuracy with lower radiation exposure. Hybrid imaging (PET/MR and PET/CT) hold promise for grading inflammation in Crohn's disease.

SUMMARY

The potential benefits of new cross-sectional imaging techniques in IBD include better inflammation grading, such as identification of mild degree of activity, which may be relevant whenever assessing response to treatment and, of uttermost importance, accurate preoperative detection and grading of fibrosis in stricturing Crohn's disease, facilitating surgical vs. medical therapeutic decisions.

Assessing Mucosal Inflammation in a DSS-Induced Colitis Mouse Model by MR Colonography

Inflammatory bowel disease (IBD) is characterized by a chronic flaring inflammation of the gastrointestinal tract. To determine disease activity, the inflammatory state of the colon should be assessed. Endoscopy in patients with IBD aids visualization of mucosal inflammation. However, because the mucosa is fragile, there is a significant risk of perforation. In addition, the technique is based on grading of the entire colon, which is highly operator-dependent. An improved, noninvasive, objective magnetic resonance imaging (MRI) technique will effectively assess pathologies in the small intestinal mucosa, more specifically, along the colon, and the bowel wall and surrounding structures. Here, dextran sodium sulfate polymer induced acute colitis in mice that was subsequently characterized by multisection magnetic resonance colonography. This study aimed to develop a noninvasive, objective, quantitative MRI technique for detecting mucosal inflammation in a dextran sodium sulfate–induced colitis mouse model. MRI results were correlated with endoscopic and histopathological evaluations.

Monitoring of small bowel Crohn's disease

In recent years, the therapeutic paradigm in Crohn's disease has shifted from a mere symptom-oriented approach, to aiming to healing of the underlying inflammation and prevention of long-term structural complications. Such 'treat-to-target' approach may allow for a more stable disease course with less hospitalizations, lower requirement for surgery and improved quality of life. In Crohn's disease, the small bowel is affected in the majority of patients; frequently, Crohn's involves only the small bowel, which remains inaccessible to conventional ileocolonoscopic techniques. Thus, non-invasive monitoring techniques are crucial for accurate disease assessment. Areas covered: This review addresses the indications and clinical implications of non-invasive small bowel monitoring modalities (magnetic resonance enterography, intestinal ultrasound, capsule endoscopy) in the assessment and management of Crohn's disease. Expert commentary: This review addresses the limitations of the current knowledge and future areas of research, including the possible utilization of transmural healing as an imaging target and the need to establish clear quantitative target values to guide treatment by imaging findings in Crohn's disease.

Pilot study of endoscopic retrograde 3-dimensional - computed tomography enteroclysis for the assessment of Crohn's disease

Purpose

Endoscopic retrograde ileography (ERIG) is developed in our institute and applied clinically for the diagnosis and assessment of the Crohn’s disease activity. We have further improved the technique using 3-dimensional – computed tomography enteroclysis (3D-CTE) and conducted a retrospective study to determine the feasibility and the diagnostic value of endoscopic retrograde 3D-CTE (ER 3D-CTE) in Crohn’s disease patients in a state of remission.

Methods

Thirteen Crohn’s patients were included in this pilot study. CTE was performed after the infusion of air or CO₂ through the balloon tube following conventional colonoscopy. The primary endpoint of this study was to assess the safety of this method. Secondarily, the specific findings of Crohn’s disease and length of the visualized small intestine were assessed.

Results

The procedures were completed without any adverse events. Gas passed through the small intestine and enterographic images were obtained in 10 out of 13 cases, but, in the remaining patients, insertion of the balloon tubes into the terminal ileum failed. Various features specific to Crohn’s disease were visualized using ER 3D-CTE. A cobble stone appearance or hammock-like malformation was specific and effective for diagnosing Crohn’s disease and the features of anastomosis after the surgical operations were also well described. Therefore, this technique may be useful after surgery.

Conclusion

In this study, ER 3D-CTE was performed safely in Crohn’s disease patients and may be used for the diagnosis and follow-up of this disease.

Colonic obstruction caused by video capsule entrapment in a metal stent

Video capsule endoscopy (VCE) has become the method of choice for visualizing the small bowel mucosa and is generally considered to be a safe method. Although uncommon, the most feared complication of VCE is capsule retention that can potentially lead to life-threatening bowel obstruction. Herein, we present for the first time a case of capsule retention in a colonic stent. The patient had known Crohn's disease with colonic involvement and underwent an uneventful but incomplete small bowel VCE for assessment of disease activity and extension for optimizing medical treatment. Five months later, the patient presented with intestinal obstruction due to a Crohn's-stricture in the sigmoid colon, which was successfully decompressed with a self-expandable metal stent. Nonetheless, two days later the patient showed signs of bowel obstruction again and abdominal X-ray showed that the capsule was trapped in the metal stent in the sigmoid colon. Subsequently, emergency surgery was performed and the patient fully recovered. Intestinal capsule retention necessitating interventional removal is rare. This report describes a unique case of capsule retention in a colonic metal stent and highlights the potential risk of performing capsule endoscopy examinations in patients with gastrointestinal stents.

Capsule Endoscopy and Deep Enteroscopy in Irritable Bowel Disease

In approximately one-third of Crohn's disease patients, the disease is confined to the small bowel, inaccessible to the reach of standard endoscopy. Thorough and complete evaluation of the small bowel is crucial in such patients for the initial diagnosis, prognostication, and disease monitoring. Video capsule endoscopy and device-assisted enteroscopy have revolutionized the ability to visualize the small-bowel mucosa. This article reviews the literature pertaining to the use of capsule endoscopy and deep enteroscopy in established Crohn's disease, including the major indications, applications, and safety issues.

Type 1 Diabetes and Dysfunctional Intestinal Homeostasis

Despite the relatively high frequency of gastrointestinal (GI) disorders in individuals with type 1 diabetes (T1D), termed diabetic enteropathy (DE), the pathogenic mechanisms of these disorders remain to be elucidated. While previous studies have assumed that DE is a manifestation of diabetic autonomic neuropathy, other contributing factors such as enteric hormones, inflammation, and microbiota were later recognized. More recently, the emerging role of intestinal stem cells (ISCs) in several GI diseases has led to a new understanding of DE. Given the absence of diagnostic methods and the lack of broadly efficacious therapeutic remedies in DE, targeting factors and pathways that control ISC homeostasis and are dysfunctional in DE may represent a new path for the detection and cure of DE.

Ionizing radiation exposure is still increasing in Crohn's disease: Who should be blamed?

BACKGROUND AND AIM

Crohn's disease (CD) patients undergo many radiological studies employing ionizing radiation for diagnosis and management purposes. Our aim was to assess the total radiation exposure of our patients over the years, to estimate the risk factors for exposure to high doses, and to correlate radiation exposure to immunosuppression.

METHODS

The cumulative effective dose of radiation (CEDR) was calculated multiplying the number of imaging studies by the effective dose of each examination.

RESULTS

A total of 451 patients with CD (226 female) were followed during 11.0 years (interquartile range [IQR]: 6.0-16.0), with 52.1% of the patients being classified with penetrating (B3) and 38.6% being steroid-dependent. About 16% were exposed to high-radiation dose levels (CEDR >50 mSv) and 4% were exposed to CEDR >100 mSv. The mean CEDR between age 26 and 35 years was 12.539 mSv and a significant dose of radiation (over 50 mSv) was achieved at a median age of 40 (IQR: 29.0-47.0). Abdominal-pelvic computed tomography scan was the examination that contributed the most for CEDR. Patients with B3 phenotype, previous surgery, azathioprine, and anti-tumor necrosis factor (TNF)-α therapy were exposed earlier on the course of the disease to CEDR >50 mSv (p < 0.001). The value of CEDR in the patients under immunosuppression mainly increased in the first year of immunosuppression.

CONCLUSION

Penetrating phenotype, abdominal surgery, steroid resistance or steroid dependence, and treatment with anti-TNF-α and azathioprine were predictive factors for high CEDR. It was also demonstrated that immunosuppression and anti-TNF-α treatment were followed by a sustained increment of radiation exposure and that a significant dose of radiation was achieved <40 years of age.

PET/MR Versus PET/CT Imaging: Impact on the Clinical Management of Small-Bowel Crohn's Disease

BACKGROUND AND AIMS

The aim of this study was to compare the accuracy and clinical impact of hybrid positron emission tomography [PET]/magnetic resonance-enterography [MR-E] and PET/computed tomography-enterography [CT-E] in patients with Crohn's disease [CD].

METHODS

A total of 35 patients with symptomatic small-bowel CD who were scheduled to undergo operation were evaluated before operation by same-day PET/CT-E and PET/MR-E. PET/MR-E was also compared with MR-E alone. Imaging accuracy for detecting pathological sites and discriminating between fibrotic and inflammatory strictures was assessed. Treatment was adjusted according to imaging findings and change in medical/surgical strategy was also evaluated.

RESULTS

PET/CT-E, PET/MR-E, and MR-E were equally accurate in detecting CD sites. PET/MR-E was more accurate in assessing extra-luminal disease [p = 0.002], which was associated with higher need for stoma [p = 0.022] and distant localisation [p = 0.002]. When the latter was observed, laparoscopy was started with hand-assisted device, reducing operative time [p = 0.022]. PET/MR-E was also more accurate in detecting a fibrotic component compared with PET/CT-E [p = 0.043] and with MR-E [p = 0.024]. Fibrosis was more frequently classified as inflammation with MR-E compared with PET/MR-E [p = 0.019]. Out of 8 patients with predominantly inflammatory CD who received medical treatment, 6 [75%] remained surgery free. Overall, 29 patients received surgery. At median follow-up of 9 [6-22] months, no recurrences occurred in either the medical or the surgical group.

CONCLUSIONS

Preoperative PET/MR-E imaging is highly accurate for assessing CD lesions before operation and contributed to clinical management of patients with small-bowel CD more often than PET/CT-E.

Inflammatory bowel disease imaging: Current practice and future directions

The purpose of this paper is to evaluate the role of imaging in inflammatory bowel disease (IBD), including detection of extraluminal complications and extraintestinal manifestations of IBD, assessment of disease activity and treatment response, and discrimination of inflammatory from fibrotic strictures. IBD is a chronic idiopathic disease affecting the gastrointestinal tract that is comprised of two separate, but related intestinal disorders; Crohn’s disease and ulcerative colitis. The paper discusses, in detail the pros and cons of the different IBD imaging modalities that need to be considered in order to optimize the imaging and clinical evaluation of patients with IBD. Historically, IBD evaluation of the bowel has included imaging to assess the portions of the small bowel that are inaccessible to optical endoscopic visualization. This traditionally was performed using barium fluoroscopic techniques; however, cross-sectional imaging techniques (computed tomography and magnetic resonance imaging) are being increasingly utilized for IBD evaluation because they can simultaneously assess mural and extramural IBD manifestations. Recent advances in imaging technology, that continue to improve the ability of imaging to noninvasively follow disease activity and treatment response, are also discussed. This review article summarizes the current imaging approach in inflammatory bowel disease as well as the role of emerging imaging modalities.

Magnetic resonance enterography or video capsule endoscopy - what do Crohn's disease patients prefer?

BACKGROUND

Despite differences in the information obtained by capsule endoscopy (CE) and magnetic resonance enterography (MRE), one of these modalities is usually needed when evaluating disease activity. There are no data on patients' preference that would help guide the choice between these two modalities in these instances.

AIM

To compare patients' tolerance and preference to MRE versus CE.

PATIENTS AND METHODS

Patients with known small bowel Crohn's disease (CD) in clinical remission (Crohn's disease activity index [CDAI] <150) or with mild symptoms (CDAI <220) were prospectively recruited. All patients underwent MRE followed by CE. Patients were asked to fill out a questionnaire addressing specific points regarding inconvenience during the preparation for the procedures, the procedures, and postprocedures. Side effects and procedure preference were addressed. Questionnaires were included for analysis only when more than 95% of the items were addressed.

RESULTS

Fifty-six patients fulfilled inclusion criteria. Pre-exam discomfort, during-exam discomfort, nausea, vomiting, bloating, and abdominal pain were all significantly more prominent in MRE as compared to CE (P<0.0001, P<0.0001, P<0.0001, P=0.009, P=0.0002, P<0.0001, respectively). MRE was perceived as a more difficult procedure (P<0.0001). Furthermore, MRE was associated with a specific adverse event - claustrophobia. Seventy-eight percent of patients (44 patients) preferred to repeat CE as compared to 22% (P<0.0001) who preferred MRE.

CONCLUSION

CE was better tolerated by CD patients compared to MRE and was preferred by 78% of patients. The superior tolerability of CE should be considered along with the diagnostic features, and more data sought when choosing between these two modalities for CD patients for long-term follow-up.

Optimising the Inflammatory Bowel Disease Unit to Improve Quality of Care: Expert Recommendations

INTRODUCTION

The best care setting for patients with inflammatory bowel disease [IBD] may be in a dedicated unit. Whereas not all gastroenterology units have the same resources to develop dedicated IBD facilities and services, there are steps that can be taken by any unit to optimise patients' access to interdisciplinary expert care. A series of pragmatic recommendations relating to IBD unit optimisation have been developed through discussion among a large panel of international experts.

METHODS

Suggested recommendations were extracted through systematic search of published evidence and structured requests for expert opinion. Physicians [n = 238] identified as IBD specialists by publications or clinical focus on IBD were invited for discussion and recommendation modification [Barcelona, Spain; 2014]. Final recommendations were voted on by the group. Participants also completed an online survey to evaluate their own experience related to IBD units.

RESULTS

A total of 60% of attendees completed the survey, with 15% self-classifying their centre as a dedicated IBD unit. Only half of respondents indicated that they had a defined IBD treatment algorithm in place. Key recommendations included the need to develop a multidisciplinary team covering specifically-defined specialist expertise in IBD, to instil processes that facilitate cross-functional communication and to invest in shared care models of IBD management.

CONCLUSIONS

Optimising the setup of IBD units will require progressive leadership and willingness to challenge the status quo in order to provide better quality of care for our patients. IBD units are an important step towards harmonising care for IBD across Europe and for establishing standards for disease management programmes.

Software for enhanced video capsule endoscopy: challenges for essential progress

Video capsule endoscopy (VCE) has revolutionized the diagnostic work-up in the field of small bowel diseases. Furthermore, VCE has the potential to become the leading screening technique for the entire gastrointestinal tract. Computational methods that can be implemented in software can enhance the diagnostic yield of VCE both in terms of efficiency and diagnostic accuracy. Since the appearance of the first capsule endoscope in clinical practice in 2001, information technology (IT) research groups have proposed a variety of such methods, including algorithms for detecting haemorrhage and lesions, reducing the reviewing time, localizing the capsule or lesion, assessing intestinal motility, enhancing the video quality and managing the data. Even though research is prolific (as measured by publication activity), the progress made during the past 5 years can only be considered as marginal with respect to clinically significant outcomes. One thing is clear-parallel pathways of medical and IT scientists exist, each publishing in their own area, but where do these research pathways meet? Could the proposed IT plans have any clinical effect and do clinicians really understand the limitations of VCE software? In this Review, we present an in-depth critical analysis that aims to inspire and align the agendas of the two scientific groups.