The role of molecular imaging in detecting fibrosis in Crohn's disease

Fibrosis is a pathological process that occurs due to chronic inflammation, leading to the proliferation of fibroblasts and the excessive deposition of extracellular matrix (ECM). The process of long-term fibrosis initiates with tissue hypofunction and progressively culminates in the ultimate manifestation of organ failure. Intestinal fibrosis is a significant complication of Crohn's disease (CD) that can result in persistent luminal narrowing and strictures, which are difficult to reverse. In recent years, there have been significant advances in our understanding of the cellular and molecular mechanisms underlying intestinal fibrosis in inflammatory bowel disease (IBD). Significant progress has been achieved in the fields of pathogenesis, diagnosis, and management of intestinal fibrosis in the last few years. A significant amount of research has also been conducted in the field of biomarkers for the prediction or detection of intestinal fibrosis, including novel cross-sectional imaging modalities such as positron emission tomography (PET) and single photon emission computed tomography (SPECT). Molecular imaging represents a promising biomedical approach that enables the non-invasive visualization of cellular and subcellular processes. Molecular imaging has the potential to be employed for early detection, disease staging, and prognostication in addition to assessing disease activity and treatment response in IBD. Molecular imaging methods also have a potential role to enabling minimally invasive assessment of intestinal fibrosis. This review discusses the role of molecular imaging in combination of AI in detecting CD fibrosis.

Performance of three predictive scores to avoid delayed diagnosis of significant blunt bowel and mesenteric injury: A 12-year retrospective cohort study

BACKGROUND

Avoiding missed diagnosis and therapeutic delay for significant blunt bowel and mesenteric injuries (sBBMIs) after trauma is still challenging despite the widespread use of computed tomography (CT). Several scoring tools aiming at reducing this risk have been published. The purpose of the present work was to assess the incidence of delayed (>24 hours) diagnosis for sBBMI patients and to compare the predictive performance of three previously published scores using clinical, radiological, and laboratory findings: the Bowel Injury Prediction Score (BIPS) and the scores developed by Raharimanantsoa Score (RS) and by Faget Score (FS).

METHODS

A population-based retrospective observational cohort study was conducted; it included adult trauma patients after road traffic crashes admitted to Lausanne University Hospital, Switzerland, between 2008 and 2019 (n = 1,258) with reliable information about sBBMI status (n = 1,164) and for whom all items for score calculation were available (n = 917). The three scores were retrospectively applied on all patients to assess their predictive performance.

RESULTS

The incidence of sBBMI after road traffic crash was 3.3% (38 of 1,164), and in 18% (7 of 38), there was a diagnostic and treatment delay of more than 24 hours. The diagnostic performances of the FS, the RS, and the BIPS to predict sBBMI, expressed as the area under the receiver operating characteristic curve, were 95.3% (95% confidence interval [CI], 92.7-97.9%), 89.2% (95% CI, 83.2-95.3%), and 87.6% (95% CI, 81.8-93.3%) respectively.

CONCLUSION

The present study confirms that diagnostic delays for sBBMI still occur despite the widespread use of abdominal CT. When CT findings during the initial assessment are negative or equivocal for sBBMI, using a score may be helpful to select patients for early diagnostic laparoscopy. The FS had the best individual diagnostic performance. However, the BIPS or the RS, relying on clinical and laboratory variables, may be helpful to select patients for early diagnostic laparoscopy when there are unspecific CT signs of bowel or mesenteric injury.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level III.

Study of ischemic progression in different intestinal tissue layers during acute intestinal ischemia using swept-source optical coherence tomography angiography

In acute intestinal ischemia, the progression of ischemia varies across different layers of intestinal tissue. We established a mouse model and used swept-source optical coherence tomography (OCT) to observe the intestinal ischemic process longitudinally in different tissue layers. Employing a method that combines asymmetric gradient filtering with adaptive weighting, we eliminated the vessel trailing phenomenon in OCT angiograms, reducing the confounding effects of superficial vessels on the imaging of deeper vasculature. We quantitatively assessed changes in vascular perfusion density (VPD), vessel length, and vessel average diameter across various intestinal layers. Our results showed a significant reduction in VPD in all layers during ischemia. The mucosa layer experienced the most significant impact, primarily due to disrupted capillary blood flow, followed by the submucosa layer, where vascular constriction or decreased velocity was the primary factor.

Bowel Stiffness Assessed by Shear-Wave Ultrasound Elastography Predicts Disease Behavior Progression in Patients With Crohn's Disease

INTRODUCTION

There is a lack of reliable predictors of disease behavior progression in patients with Crohn's disease (CD). Real-time shear-wave elastography (SWE) is a novel method for evaluating tissue stiffness. However, its value for assessing CD has not yet been investigated. We aimed to explore the value of SWE and other ultrasound parameters at diagnosis in predicting CD behavior progression.

METHODS

We retrospectively collected data from patients with CD with the nonstenotic nonpenetrating disease (B1 phenotype based on the Montreal classification). All patients underwent intestinal ultrasound at baseline and were followed up. The end point was defined as disease behavior progression to stricturing (B2) or penetrating (B3) disease. Cox regression analysis was performed for the association between baseline characteristics and subsequent end points. In addition, a multivariate nomogram was established to predict the risk of disease behavior progression quantitatively.

RESULTS

A total of 130 patients with CD with B1 phenotype were enrolled. Twenty-seven patients (20.8%) developed B2 or B3 disease, with a median follow-up of 33 months. Multivariate analysis identified that SWE was the only independent predictor of disease behavior progression (hazard ratio 1.08, 95% confidence interval 1.03-1.12, P = 0.001). A reverse of the HR appeared at the cutoff 12.75 kPa. The nomogram incorporating SWE and other clinical characteristics showed a good prediction performance (area under the curve = 0.792).

DISCUSSION

Intestinal stiffness assessed using SWE is an independent predictor of disease behavior progression in patients with CD. Patients with CD with SWE >12.75 kPa at diagnosis are prone to progress toward stricturing or penetrating diseases.

Photoacoustic Imaging as a Novel Non-invasive Biomarker to Assess Intestinal Tissue Oxygenation and Motility in Neonatal Rats

BACKGROUND

Within the premature infant intestine, oxygenation and motility play key physiological roles in healthy development and disease such as necrotizing enterocolitis. To date, there are limited techniques to reliably assess these physiological functions that are also clinically feasible for critically ill infants. To address this clinical need, we hypothesized that photoacoustic imaging (PAI) can provide non-invasive assessment of intestinal tissue oxygenation and motility to characterize intestinal physiology and health.

METHODS

Ultrasound and photoacoustic images were acquired in 2-day and 4-day old neonatal rats. For PAI assessment of intestinal tissue oxygenation, an inspired gas challenge was performed using hypoxic, normoxic, and hyperoxic inspired oxygen (FiO2). For intestinal motility, oral administration of ICG contrast agent was used to compare control animals to an experimental model of loperamide-induced intestinal motility inhibition.

RESULTS

PAI demonstrated progressive increases in oxygen saturation (sO2) as FiO2 increased, while the pattern of oxygen localization remained relatively consistent in both 2-day and 4-day old neonatal rats. Analysis of intraluminal ICG contrast enhanced PAI images yielded a map of the motility index in control and loperamide treated rats. From PAI analysis, loperamide significantly inhibited intestinal motility, with a 32.6% decrease in intestinal motility index scores in 4-day old rats.

CONCLUSION

These data establish the feasibility and application of PAI to non-invasively and quantitatively measure intestinal tissue oxygenation and motility. This proof-of-concept study is an important first step in developing and optimizing photoacoustic imaging to provide valuable insight into intestinal health and disease to improve the care of premature infants.

Intestinal ultrasound in inflammatory bowel disease

Intestinal ultrasound (IUS) is non-invasive, fast, cheap, and well-tolerated and requires no preparation and is thus applicable as a point-of-care monitoring tool of inflammatory bowel disease (IBD). Evidence suggests that IUS is comparable to other standard monitoring modalities, i.e., endoscopy, MRI, calprotectin, and C-reactive protein and might be more accurate in predicting response to treatment at an early stage consequently allowing for timely optimised treatment. This review finds that integrating IUS as the standard of care in every IBD outpatient clinic and as the primary outcome in future medical trials seems inevitable.

Clinical Application of Intestinal Ultrasound in Inflammatory Bowel Disease

PURPOSE OF REVIEW

Intestinal ultrasound (IUS) is a non-invasive, accurate, and well-tolerated tool that provides real-time assessment of inflammatory bowel disease (IBD) activity and is therefore an ideal monitoring tool. This review describes the evolving role of IUS in each phase of clinical management of IBD.

RECENT FINDINGS

Accumulating evidence has demonstrated that IUS is an excellent tool for the assessment of suspected IBD, with a very high negative predictive value. It accurately assesses disease activity, disease complications, and in the pre-treatment phase, provides a benchmark for subsequent follow-up. IUS can detect early therapeutic response and correlates well with other established monitoring modalities with arguably superior predictive capabilities and ability to assess a deeper degree of remission, transmural healing (TH). IUS has a crucial role in the management of IBD and has ushered in a new era of monitoring with more rapid evaluation and the opportunity for early optimization, deeper therapeutic targets, and improved outcomes.

Intestinal ultrasonography in pediatric population

Bowel ultrasound (US) is a low-cost, non-invasive, bed side practice and a reproducible procedure that represents a high yield tool in clinical practice and in the diagnostic workup of a consistent group of acute and chronic gastrointestinal (GI) tract disease. Moreover, in case of GI diseases of neonatal and pediatric age, it allows an easier evaluation due to the small body size and scarce presence of fat tissue in the abdominal wall and peritoneal cavity and gas content. No particular preparation of the patient is needed, nevertheless a 3- to 5-hour fasting state improves the quality of the examination. The exam focuses on wall thickness and stratification, lumen content, distensibility and compressibility, presence of peristalsis of explorable segment of the GI tract and includes the investigation of mesentery, perivisceral tissues and nodes features. Color doppler flowmetry admits a qualitative evaluation of GI wall and mesentery vascularization. Healthy GI wall appears at a US evaluation as a multilayered structure in which hyperechoic and hypoechoic layers alternate sequentially. In this article we provide a quickly available overview on findings, signs and applications of US in major GI pediatric diseases.

Automatized Detection of Crohn's Disease in Intestinal Ultrasound Using Convolutional Neural Network

INTRODUCTION

The use of intestinal ultrasound (IUS) for the diagnosis and follow-up of inflammatory bowel disease is steadily growing. Although access to educational platforms of IUS is feasible, novice ultrasound operators lack experience in performing and interpreting IUS. An artificial intelligence (AI)-based operator supporting system that automatically detects bowel wall inflammation may simplify the use of IUS by less experienced operators. Our aim was to develop and validate an artificial intelligence module that can distinguish bowel wall thickening (a surrogate of bowel inflammation) from normal bowel images of IUS.

METHODS

We used a self-collected image data set to develop and validate a convolutional neural network module that can distinguish bowel wall thickening >3 mm (a surrogate of bowel inflammation) from normal bowel images of IUS.

RESULTS

The data set consisted of 1008 images, distributed uniformly (50% normal images, 50% abnormal images). Execution of the training phase and the classification phase was performed using 805 and 203 images, respectively. The overall accuracy, sensitivity, and specificity for detection of bowel wall thickening were 90.1%, 86.4%, and 94%, respectively. The network exhibited an average area under the ROC curve of 0.9777 for this task.

CONCLUSIONS

We developed a machine-learning module based on a pretrained convolutional neural network that is highly accurate in the recognition of bowel wall thickening on intestinal ultrasound images in Crohn's disease. Incorporation of convolutional neural network to IUS may facilitate the use of IUS by inexperienced operators and allow automatized detection of bowel inflammation and standardization of IUS imaging interpretation.

Dye-free visualisation of intestinal perfusion using laser speckle contrast imaging in laparoscopic surgery: a prospective, observational multi-centre study

INTRODUCTION

Intraoperative perfusion imaging may help the surgeon in creating the intestinal anastomoses in optimally perfused tissue. Laser speckle contrast imaging (LSCI) is such a perfusion visualisation technique that is characterized by dye-free, real-time and continuous imaging. Our aim is to validate the use of a novel, dye-free visualization tool to detect perfusion deficits using laparoscopic LSCI.

METHODS

In this multi-centre study, a total of 64 patients were imaged using the laparoscopic laser speckle contrast imager. Post-operatively, surgeons were questioned if the additional visual feedback would have led to a change in clinical decision-making.

RESULTS

This study suggests that the laparoscopic laser speckle contrast imager PerfusiX-Imaging is able to image colonic perfusion. All images were clear and easy to interpret for the surgeon. The device is non-disruptive of the surgical procedure with an average added surgical time of 2.5 min and no change in surgical equipment. The potential added clinical value is accentuated by the 17% of operating surgeons indicating a change in anastomosis location. Further assessment and analysis of both white light and PerfusiX perfusion images by non-involved, non-operating surgeons showed an overall agreement of 80%.

CONCLUSION

PerfusiX-Imaging is a suitable laparoscopic perfusion imaging system for colon surgery that can visualize perfusion in real-time with no change in surgical equipment. The additional visual feedback could help guide the surgeons in placing the anastomosis at the most optimal site.

Insights into acute mesenteric ischaemia: an up-to-date, evidence-based review from a mesenteric stroke centre unit

Radiologists play a central role in the diagnostic and prognostic evaluation of patients with acute mesenteric ischaemia (AMI). Unfortunately, more than half of AMI patients undergo imaging with no prior suspicion of AMI, making identifying this disease even more difficult. A confirmed diagnosis of AMI is ideally made with dynamic contrast-enhanced CT but the diagnosis may be made on portal-venous phase images in appropriate clinical settings. AMI is diagnosed on CT based on the identification of vascular impairment and bowel ischaemic injury with no other cause. Moreover, radiologists must evaluate the probability of bowel necrosis, which will influence the treatment options.AMI is usually separated into different entities: arterial, venous, non-occlusive and ischaemic colitis. Arterial AMI can be occlusive or stenotic, the dominant causes being atherothrombosis, embolism and isolated superior mesenteric artery (SMA) dissection. The main finding in the bowel is decreased wall enhancement, and necrosis can be suspected when dilatation >25 mm is identified. Venous AMI is related to superior mesenteric vein (SMV) thrombosis as a result of a thrombophilic state (acquired or inherited), local injury (cancer, inflammation or trauma) or underlying SMV insufficiency. The dominant features in the bowel are hypoattenuating wall thickening with submucosal oedema. Decreased enhancement of the involved bowel suggests necrosis. Non-occlusive mesenteric ischaemia (NOMI) is related to impaired SMA flow following global hypoperfusion associated with low-flow states. There are numerous findings in the bowel characterised by diffuse extension. An absence of bowel enhancement and a thin bowel wall suggest necrosis in NOMI. Finally, ischaemic colitis is a sub-entity of arterial AMI and reflects localised colon ischaemia-reperfusion injury. The main CT finding is a thickened colon wall with fat stranding, which seems to be unrelated to SMA or inferior mesenteric artery lesions. A precise identification and description of vascular lesions, bowel involvement and features associated with transmural necrosis is needed to determine patient treatment and outcome.

Intestinal ultrasound may be a useful tool in monitoring acute rejection following intestinal transplantation

BACKGROUND

Acute rejection is the leading cause of mortality and morbidity for children following intestinal transplantation. Rapid detection and prompt treatment are critical; however, the only reliable method of diagnosis and monitoring is endoscopic graft biopsies. The required regular anesthetics are particularly problematic in children, and non-invasive strategies are needed.

METHODS

We describe the intestinal ultrasound findings of three children before and after treatment for rejection. Ultrasounds were performed within 24 h of endoscopically obtained biopsies which were used to establish a diagnosis of rejection and to define severity. A single sonographer performed the ultrasounds and was blinded to biopsy results at the time of the scanning. These findings are provided in the context of the ultrasound appearance of seven children who had no features of rejection on surveillance biopsies.

RESULTS

Intestinal ultrasound demonstrated increased bowel wall thickness, vascularity, and mesenteric inflammation during moderate to severe rejection episodes. The submucosal layer was particularly thickened, which may represent a finding more specific for rejection. All patients demonstrated improvement in all quantitative ultrasound features correlating with the resolution of acute cellular rejection on histology. Patients with no evidence of rejection on biopsy had a bowel wall thickness range of 0.9-2.8 mm, suggesting a normal upper limit of 3 mm.

CONCLUSION

Moderate and severe acute rejection may be detected and response to treatment can be monitored by intestinal ultrasound and, correlating with clinical improvement, can aid in follow-up.

Wide field-of-view fluorescence imaging for organ-level lineage tracing of rare intestinal stem cell populations

Significance

Lineage tracing using fluorescent reporters is a common tool for monitoring the expression of genes and transcription factors in stem cell populations and their progeny. The zinc-binding protein 89 (ZBP-89/Zfp148 mouse gene) is a transcription factor that plays a role in gastrointestinal (GI) stem cell maintenance and cellular differentiation and has been linked to the progression of colon cancer. While lineage tracing is a useful tool, it is commonly performed with high-magnification microscopy on a small field of view within tissue sections, thereby limiting the ability to resolve reporter expression at the organ level. Furthermore, this technique requires extensive tissue processing, which is time consuming and requires euthanizing the animal. Further knowledge could be elucidated by measuring the expression of fluorescent reporters across entire organs with minimal tissue processing.

Aim

We present the application of wide-field fluorescence imaging for whole-organ lineage tracing of an inducible Zfp148-tdTomato-expressing transgenic mouse line to assess the expression of ZBP-89/Zfp148 in the GI tract.

Approach

We measured tdTomato fluorescence in ex vivo organs at time points between 24 h and 6 months post-induction. Fluctuations in tdTomato expression were validated by fluorescence microscopy of tissue sections.

Results

Quantification of the wide field-of-view images showed a statistically significant increase in fluorescent signal across the GI tract between transgenic mice and littermate controls. The results also showed a gradient of decreasing reporter expression from proximal to distal intestine, suggesting a higher abundance of ZBP-89 expressing stem cells, or higher expression of ZBP-89 within the stem cells, in the proximal intestine.

Conclusions

We demonstrate that wide-field fluorescence imaging is a valuable tool for monitoring whole-organ expression of fluorescent reporters. This technique could potentially be applied in vivo for longitudinal assessment of a single animal, further enhancing our ability to resolve rare stem cell lineages spatially and temporally.

New score models for assessing disease activity in Crohn's disease based on bowel ultrasound and biomarkers: Ideal surrogates for endoscopy or imaging

Disease activity evaluation is important in Crohn's disease (CD). We aimed to establish new disease activity indices for CD based on noninvasive parameters. The data of 110 patients with CD were retrospectively analyzed. Parameters from bowel ultrasound and biomarkers were measured to select the variables included in the models by univariate analysis. Logistic regression analysis was performed to predict mucosal and transmural activities defined by ileocolonoscopy or computed tomography enterography, respectively. The models' performance was measured by the area under the receiver operating characteristic (ROC) curve (AUC). Leave-one-out cross validation (LOOCV) was applied to adjust for overconfidence in the newly established score models. To predict mucosal activity, erythrocyte sedimentation rate (ESR) and (LimG × BWT)-SUM (the sum of the product of Limberg grade [LimG] and bowel wall thickness [BWT] of each bowel segment) were selected for model A, and the equation was A = 2 × ESR + 9.3 × (LimG × BWT)-SUM. The AUC of ROC, sensitivity, and specificity were 0.927%, 89.8%, and 86.4%, respectively. The AUC of the ROC curve verified by LOOCV was 0.913. To predict transmural activity, albumin (ALB) and LimG-SUM (the sum of the LimG of all the bowel segments) were selected for model B, which was established as B = -1.3 × ALB +1.7 × LimG-SUM. The AUC of ROC, sensitivity, and specificity were 0.851%, 78.0%, and 84.2%, respectively. The AUC of the ROC curve verified by LOOCV was 0.833. Nomograms were developed for two score models. New score models based on noninvasive parameters established in this study showed good abilities in detecting active disease and performed well in the validation phase.

The Role of Noninvasive Surrogates of Inflammation in Monitoring Pediatric Inflammatory Bowel Diseases: The Old and the New

Effectiveness of limited available therapies for pediatric inflammatory bowel disease has reached stagnation. Previous non-invasive monitoring strategies have relied upon cumbersome tools to evaluate clinical symptoms and biochemical markers that do not reflect endoscopic activity or respond quickly to treatments. Novel, patient-centric, and highly accurate, monitoring strategies with a focus on intestinal ultrasound for a direct, precise monitoring of activity to achieve disease modification are now possible. Ultimately, research on the optimal tight control monitoring strategies, individualized to each pediatric inflammatory bowel disease patient, are in development and offer a hope to potential therapeutic ceiling breakthrough on the horizon.

A Prospective Management Strategy for Heterotaxy Syndrome with Intestinal Rotation Abnormalities: Imaging Does Not Predict Need for Surgery

PURPOSE

Heterotaxy syndrome (HS) affects right-left anatomical development in 3% of children with congenital heart disease. Commonly, these patients have intestinal rotation abnormalities (IRA) that differ from typical malrotation. In this prospective study, we examine the development of a management pathway, imaging findings, and clinical course of patients with HS and IRA.

METHODS

After literature review, a multispecialty focus group designed a pathway for HS. Participants from a single institution were prospectively enrolled from 2016 to 2019. They underwent an abdominal ultrasound and UGI, however timing was variable based on symptoms. Symptomatic IRA was defined as feeding intolerance, bilious or non-bilious vomiting, bloating, severe reflux, and intermittent pain or abdominal distention. Screening for symptoms occurred every three months for the first two years and then annually.

RESULTS

18 participants were followed for a median of 5.0 years. Three clinical categories were identified: 1) asymptomatic, not requiring intestinal surgery, 72.2%, 2) symptomatic with feeding intolerance or failure to thrive requiring gastrostomy placement and diagnostic laparoscopy with Ladd procedure, 16.7%, and 3) symptomatic requiring urgent exploration for suspicion of volvulus, 11.1%. Need for surgery did not necessarily correlate with US and/or UGI findings.

CONCLUSIONS

In children with HS and IRA, postnatal imaging did not inform the need for intestinal surgery. Although rare, volvulus or other forms of proximal obstruction can be anticipated, and symptomatic patients should be offered surgical intervention. A multidisciplinary care pathway for patients with HS and IRA can coordinate care and help counsel families on the likelihood of needing intestinal surgery for IRA.

LEVEL OF EVIDENCE

Level II.

TYPE OF STUDY

Prospective Cohort Study.

NAD(P)H Fluorescence Lifetime Imaging for the Metabolic Analysis of the Murine Intestine and Parasites During Nematode Infection

Parasites generally have a negative effect on the health of their host. They represent a huge health burden, as they globally affect the health of the infested human or animal in the long term and, thus, impact agricultural and socio-economic outcomes. However, parasite-driven immune-regulatory effects have been described, with potential therapeutic relevance for autoimmune diseases. While the metabolism in both the host and parasites contributes to their defense and is the basis for nematode survival in the intestine, it has remained largely understudied due to a lack of adequate technologies. We have developed and applied NAD(P)H fluorescence lifetime imaging to explanted murine intestinal tissue during infection with the natural nematode Heligmosomoides polygyrus to study the metabolic processes in both the host and parasites in a spatially resolved manner. The exploitation of the fluorescence lifetime of the co-enzymes nicotinamide adenine dinucleotide (NADH) and nicotinamide adenine dinucleotide phosphate (NADPH), hereafter NAD(P)H, which are preserved across species, depends on their binding status and the binding site on the enzymes catalyzing metabolic processes. Focusing on the most abundantly expressed NAD(P)H-dependent enzymes, the metabolic pathways associated with anaerobic glycolysis, oxidative phosphorylation/aerobic glycolysis, and NOX-based oxidative burst, as a major defense mechanism, were distinguished, and the metabolic crosstalk between the host and parasite during infection was characterized.

Recent advances in the use of ultrasound in Crohn's disease

INTRODUCTION

A clear consensus exists on the role of IUS for the assessment and monitoring of Crohn's disease (CD) in the 'treat-to-target' strategy.

AREAS COVERED

IUS is an accurate tool for the management of CD. It is noninvasive and well tolerated. IUS has good-to-optimal inter-operator reliability either for assessing disease activity or for evaluating treatment response, especially combining Bowel Wall Thickness (BWT) and Color Doppler Signals (CDS). IUS is able to evaluate transmural remission (TR), the ultimate goal of the 'treat-to-target' strategy. Several studies confirmed its accuracy in the assessment of the post-operative recurrence (POR). Thanks to recent advances in trans-perineal ultrasound technique (TPUS), it allows to characterize peri-anal disease and its complications. Small intestine contrast ultrasound (SICUS) and contrast-enhancement ultrasound (CEUS) may improve IUS performance, particularly in stricturing or penetrating CD. Ultrasound elastography (USE) is raising interest for its accuracy in differentiating CD phenotypes (fibrotic versus inflamed).

EXPERT OPINION

IUS is a pivotal step in the management of CD, in early assessment as in therapeutic monitoring, with advantages of evaluating transmural response. Development and validation of novel ultrasound biomarkers of activity and fibrosis, especially those linked to advanced ultrasound techniques, are expected in the coming years.

Prognostic role of intestinal ultrasound in Crohn’s disease

The majority of patients affected by Crohn’s disease (CD) develop a chronic condition with persistent inflammation and relapses that may cause progressive and irreversible damage to the bowel, resulting in stricturing or penetrating complications in around 50% of patients during the natural history of the disease. Surgery is frequently needed to treat complicated disease when pharmacological therapy failes, with a high risk of repeated operations in time. Intestinal ultrasound (IUS), a non-invasive, cost-effective, radiation free and reproducible method for the diagnosis and follow-up of CD, in expert hands, allow a precise assessment of all the disease manifestations: Bowel characteristics, retrodilation, wrapping fat, fistulas and abscesses. Moreover, IUS is able to assess bowel wall thickness, bowel wall stratification (echo-pattern), vascularization and elasticity, as well as mesenteric hypertrophy, lymph-nodes and mesenteric blood flow. Its role in the disease evaluation and behaviour description is well assessed in literature, but less is known about the potential space of IUS as predictor of prognostic factors suggesting response to a medical treatment or postoperative recurrence. The availability of a low cost exam as IUS, able to recognize which patients are more likely to respond to a specific therapy and which patients are at high risk of surgery or complications, could be a very useful instrument in the hands of IBD physician. The aim of this review is to present current evidence about the prognostic role that IUS can show in predicting response to treatment, disease progression, risk of surgery and risk of post-surgical recurrence in CD.

Intestinal ultrasound as a non-invasive tool to monitor inflammatory bowel disease activity and guide clinical decision making

Intestinal ultrasound (IUS) is a non-invasive, real-time, cross-sectional imaging tool that can be used at the point-of-care to assess disease activity in patients with Crohn’s disease or ulcerative colitis. IUS promotes quick and impactful treatment decisions that can modify disease progression and enhance patient compliance. This review will summarize the technical aspects of IUS, the evidence to support the use of IUS in disease activity monitoring, the comparison of IUS to current standard of care monitoring modalities such as colonoscopy and calprotectin, and the optimal positioning of IUS in a tight-control monitoring strategy.

Usefulness of Intestinal Ultrasound to Detect Small Intestinal Stenosis in Patients With Crohn's Disease

OBJECTIVES

Double balloon enteroscopy (DBE) with retrograde contrast is useful as a monitoring tool for small intestinal lesions in Crohn's disease (CD), but these are burdensome for patients. Intestinal ultrasound (IUS) can be used with ease in daily clinical practice, but there is less evidence regarding the accuracy of detection of small intestinal stenosis in CD. This study aimed to examine the diagnostic power of IUS for small intestinal stenosis in patients with CD.

METHODS

The findings of DBE and IUS in 86 patients with CD with small intestinal lesions were evaluated. Using DBE as the reference standard, we examined the detection rate of IUS for small intestinal stenosis. We evaluated three parameters: luminal narrowing, prestenotic dilation, and to-and-fro movement for determining stenosis using IUS. In addition, we compared the characteristics between the stenosis-detectable and stenosis-undetectable groups by IUS.

RESULTS

Of the 86 patients, 30 had small intestinal stenosis. In IUS findings, when lesions that met two or more of the three parameters were judged as stenosis, the detection rate was 70.0% for sensitivity, 98.2% for specificity, and 88.4% for accuracy. Moreover, there were patients with a younger age at diagnosis (P < 0.05) and more ileocolonic disease location (P < 0.05) in the stenosis-detectable group by IUS. The stenoses detected by IUS were significantly longer than those undetected by IUS (14.1 mm versus 5.2 mm, P < 0.05).

CONCLUSIONS

IUS delivered reliable results for clinically important small intestinal stenosis of CD with high diagnostic accuracy.

Gastroschisis ultrasound bowel characteristics demonstrate minimal impact on perinatal outcomes

BACKGROUND

Bowel dilation and bowel wall thickness are common prenatal ultrasound measurements for fetuses with gastroschisis. Data regarding antenatal sonographic bowel findings and postnatal outcomes are conflicting. Our objective was to evaluate the impact of in utero bowel measurements on perinatal outcomes in gastroschisis pregnancies.

METHODS

Retrospective cohort study of 116 pregnancies complicated by gastroschisis between 2011 and 2020. We reviewed ultrasounds documenting fetal bowel measurements. To evaluate the association of these measurements with antepartum and delivery outcomes, we ran logistic and linear models using generalized estimating equations.

RESULTS

Eleven perinatal outcomes reached statistical significance, although with minimal clinical impact given small magnitude of effect. Intra-abdominal bowel dilation was associated with a 0.5 week decrease in delivery gestational age (GA) (95% CI -0.07, -0.03) and a 6.93 g increase in birth weight (95% CI 1.54, 28.73). Intra-abdominal bowel wall thickness was associated with later GA of non-stress test (NST) start of 0.22 weeks (95% CI 0.07, 0.37), increased delivery GA of 0.08 weeks (95% CI 0.02, 0.15), 0.006 decrease in umbilical artery (UA) pH (95% CI -0.009, -0.003), 0.26 increase in UA base deficit (95% CI 0.09, 0.43), and decreased odds of cesarean delivery (OR = 0.83, 95% CI 0.70, 0.99). Extra-abdominal bowel wall thickness was associated with a 0.1 increase in UA base deficit (95% CI 0.02, 0.19) and a 0.05 increase in 5-min APGAR score (95% CI 0.01, 0.09). Stomach cross-section was associated with a 0.01 week decrease in delivery GA (95% CI -0.02, -0.001) and increased odds of receiving betamethasone (OR = 1.02, 95% CI 1.01, 1.04).

CONCLUSIONS

In utero bowel characteristics reached statistical significance for several outcomes, but with minimal meaningful clinical differences in outcomes.

Prognostic factors in patients with acute mesenteric ischemia-novel tools for determining patient outcomes

BACKGROUND

Acute mesenteric ischemia (AMI) is a devastating disease with poor prognosis. Due to the multitude of underlying factors, prediction of outcomes remains poor. We aimed to identify factors governing diagnosis and survival in AMI and develop novel prognostic tools.

METHODS

This monocentric retrospective study analyzed patients with suspected AMI undergoing imaging between January 2014 and December 2019. Subgroup analyses were performed for patients with confirmed AMI undergoing surgery. Nomograms were calculated based on multivariable logistic regression models.

RESULTS

Five hundred and thirty-nine patients underwent imaging for clinically suspected AMI, with 216 examinations showing radiological indication of AMI. Intestinal necrosis (IN) was confirmed in 125 undergoing surgery, 58 of which survived and 67 died (median 9 days after diagnosis, IQR 22). Increasing age, ASA score, pneumatosis intestinalis, and dilated bowel loops were significantly associated with presence of IN upon radiological suspicion. In contrast, decreased pH, elevated creatinine, radiological atherosclerosis, vascular occlusion (versus non-occlusive AMI), and colonic affection (compared to small bowel ischemia only) were associated with impaired survival in patients undergoing surgery. Based on the identified factors, we developed two nomograms to aid in prediction of IN upon radiological suspicion (C-Index = 0.726) and survival in patients undergoing surgery for IN (C-Index = 0.791).

CONCLUSION

As AMI remains a condition with high mortality, we identified factors predicting occurrence of IN with suspected AMI and survival when undergoing surgery for IN. We provide two new tools, which combine these parameters and might prove helpful in treatment of patients with AMI.

The Role of Ultrasound in Chronic Intestinal Diseases in Pediatric Patients

Chronic inflammatory bowel diseases (IBD) are chronic disorders of the gastrointestinal tract, with an increasing incidence in pediatric populations. Ultrasound of the intestinal wall represents the first-line imaging technique in children since it is a noninvasive method, is free of ionizing radiation, and is inexpensive. Furthermore, the absence of intestinal wall thickening has a good negative predictive value for IBD, which is greater for Crohn's disease than for ulcerative colitis. Ultrasound is used for the diagnosis of disease, for the differential diagnosis in IBD, in the follow-up of known IBD, in the definition of the site and extent of the disease, for the diagnosis of intestinal complications, for the evaluation of disease activity, in the definition of prognostic parameters, and in the post-operative follow-up.

Computed tomography enterography predicts surgical-free survival in symptomatic stricturing Crohn's disease

OBJECTIVES

The study aimed to predict surgical risks for patients with symptomatic stricturing Crohn's disease (CD) using computed tomography enterography (CTE) and to assess the association between CTE findings and pathological changes.

METHODS

Crohn's disease patients with symptomatic stricture(s) were included. Exclusion criteria were concomitant penetrating disease, intra-abdominal abscess, previous bowel resection, or asymptomatic. Patients from January 2016 to December 2019 were identified as the primary cohort and those from January 2020 to June 2020 were identified as the validation cohort. Two independent experienced radiologists evaluated CTE variables including mucosal enhancement, mural stratification, wall enhancement, comb sign, lymphadenopathy, thick non-enhancing wall, bowel wall thickness, luminal diameter, and upstream lumen. Receiver operating characteristic, logistic regression, and nomogram were performed to identify the independent predictors of surgical-free survival. Histopathological scores of surgical specimens were also evaluated.

RESULTS

198 patients (primary cohort, 123 with surgery and 75 under non-surgical intervention, and 41 patients (validation cohort) were analyzed. Bowel wall thickness < 5.9 mm, luminal stenosis > 3.35 mm, and upstream lumen < 27.5 mm were predictors of surgical-free survival for symptomatic stricturing CD patients. Logistic analysis showed the three CTE variables were the independent predictors of surgical-free survival (p < 0.001). A nomogram was developed with the concordance indexes of 0.905 and 0.892 in the primary and validation cohorts. Histopathological analysis showed bowel wall muscular hyperplasia/hypertrophy significantly correlated with luminal stenosis (r = - 0.655, p = 0.008) and combined CTE variable (r = - 0.683, p = 0.005).

CONCLUSIONS

CTE is highly predictive of disease course and surgical-free survival for patients with symptomatic stricturing CD, suggesting the important role of CTE in decision-making of treatment.

Treat to transmural healing: how to incorporate intestinal ultrasound into the treatment of inflammatory bowel disease

Intestinal ultrasound (IUS) is emerging as a key tool to achieving the therapeutic target of transmural healing in inflammatory bowel disease (IBD). IUS is a non-invasive, radiation-free, imaging modality comparable to MRI, CT and ileocolonoscopy (IC). With the appropriate training and equipment, IUS can be an easily repeatable bedside test for IBD diagnosis and disease monitoring, including treatment response. Core to successful high quality IUS employment are appropriate training and expert techniques; however, the training pathway will not be explored in this review. Given the increasing shift towards objective assessment for tight disease control, gastroenterologist-led IUS should be incorporated into the armamentarium of imaging modalities alongside radiologists, to enhance our diagnostic and monitoring toolbox. This comprehensive review aims to outline the current literature around IUS and propose the placement of IUS in a treat-to-target algorithm in IBD. Ultimately, IUS facilitates timely management decisions to optimise patient care with potential to revolutionise patient outcomes, moving towards transmural healing as the holy grail of therapy in IBD.

David Against Goliath: Direct Comparison of Handheld Bowel Sonography and Magnetic Resonance Enterography for Diagnosis of Crohn's Disease

BACKGROUND

Diagnosis of Crohn's disease (CD) requires ileo-colonoscopy (IC) and cross-sectional evaluation. Recently, "echoscopy" has been used effectively in several settings, although data about its use for CD diagnosis are still limited. Our aim was to evaluate the diagnostic accuracy of handheld bowel sonography (HHBS) in comparison with magnetic resonance enterography (MRE) for CD diagnosis.

METHODS

From September 2019 to June 2021, we prospectively recruited consecutive subjects attending our third level IBD Unit for suspected CD. Patients underwent IC, HHBS, and MRE in random order with operators blinded about the result of the other procedures. Bivariate correlation between MRE and HHBS was calculated by Spearman coefficient (r). To test the consistency between MRE and HHBS for CD location and complications, the Cohen's k measure was applied.

RESULTS

Crohn's disease diagnosis was made in 48 out of 85 subjects (56%). Sensitivity, specificity, positive predictive values, and negative predictive values for CD diagnosis were 87.50%, 91.89%, 93.33%, and 85% for HHBS; and 91.67%, 94.59%, 95.65%, and 89.74% for MRE, without significant differences in terms of diagnostic accuracy (89.41% for HHBS vs 92.94% for MRE, P = NS). Magnetic resonance enterography was superior to HHBS in defining CD extension (r = 0.67; P < .01) with a better diagnostic performance than HHBS for detecting location (k = 0.81; P < .01), strictures (k = 0.75; P < .01), abscesses (k = 0.68; P < .01), and fistulas (k = 0.65; P < .01).

CONCLUSION

Handheld bowel sonography and MRE are 2 accurate and noninvasive procedures for diagnosis of CD, although MRE is more sensitive in defining extension, location, and complications. Handheld bowel sonography could be used as effective ambulatory (or out-of-office) screening tool for identifying patients to refer for MRE examination due to high probability of CD diagnosis.

Intestinal Ultrasound in Pediatric Inflammatory Bowel Disease: Promising, but Work in Progress

Intestinal ultrasound (IUS) is increasingly used and promulgated as a noninvasive monitoring tool for children with inflammatory bowel disease because other diagnostic modalities such as colonoscopy and magnetic resonance imaging cause significant stress in the pediatric population. The most important parameters of inflammation that can be assessed using IUS are bowel wall thickness and hyperemia of the bowel wall. Research has shown that IUS has the potential to be a valuable additional point-of-care tool to guide treatment choice and to monitor and predict treatment response, although evidence of its accuracy and value in clinical practice is still limited. This review gives an update and overview of the current evidence on the use and accuracy of IUS in children with inflammatory bowel disease.

A high frequency endoscopic ultrasound imaging method combining chirp coded excitation and compressed sensing

Insufficient imaging penetration and large data acquisition are two of the major challenges of high-frequency ultrasound imaging. Based on the good autocorrelation properties of chirp signal and the feasibility of using compressed sensing theory to reconstruct high-quality ultrasound images with low sampling requirements, this paper proposed a chirp coded excitation combined with compressed sensing (CCE-CS) technique for high-frequency endoscopic ultrasound (HFEUS) imaging. The feasibility of the method was verified by a brief theoretical analysis, and the relevant parameters were selected and analyzed according to the actual engineering situation. Simulated phantoms and in-vitro tissue experiments were used to evaluate the performance of the CCE-CS. Simulation results demonstrate that CCE-CS is capable of reducing the impact of reconstruction errors and improving imaging quality through comparison with conventional methods. The reduction of reconstruction data had less impact on penetration depth, resolution and general contrast general contrast-to-noise ratio (gCNR), and the reconstructed image was closer to the original image with a maximum improvement of 37% in peak signal-to-noise ratio (PSNR). Moreover, comparisons were conducted on the digestive tract of swine, and the results show that CCE-CS is also feasible in the in-vitro environment. These results demonstrated that CCE-CS method has good potential for application to improve the imaging quality of HFEUS while reducing the sampling rate.

Comprehensive review of acute small bowel ischemia: CT imaging findings, pearls, and pitfalls

Acute small bowel ischemia is a life-threatening condition with a high mortality rate due to its lack of specific symptoms and laboratory profile, which render difficulty in establishing early diagnosis. The etiology of acute small bowel ischemia includes occlusive forms (arterial embolism, arterial thrombosis, and venous thrombosis) and nonocclusive mesenteric ischemia, of which arterial causes are far more common than venous causes. CT, the mainstay of accurate diagnoses, allows the identification of the features of vascular abnormalities and intestinal ischemic injuries, and helps clinicians to restore intestinal blood flow. Without treatment, the prognosis for acute small bowel ischemia is poor. A high index of suspicion and familiarity with the CT spectral findings of bowel ischemia are required to ensure rapid recognition of this condition.

Feasibility of Abdominal Magnetic Resonance Imaging in Patients With Residual Concentrated Enteric Contrast After Fluoroscopic Abdominal Examination

OBJECTIVE

This study aimed to evaluate the image quality, image artifacts, radiologist confidence, and ability to provide definitive diagnosis for all patients with magnetic resonance imaging (MRI) performed after an abdominal fluoroscopic examination and to determine the utility of MRI in this setting.

METHODS

Thirty-one MRI examinations performed a median of 2 days after fluoroscopic bowel evaluation (barium, n = 13; iodine, n = 18), 20 within 3 days of MRI, were retrospectively reviewed. The image quality, artifact emanating from bowel, inhomogeneity artifact, radiologist confidence, ability to render a definitive diagnosis, and identification of emergent or important findings for all MRI examinations were assessed. These same features were evaluated on 5 computed tomographies performed after fluoroscopy (before the MRI) in the same cohort.

RESULTS

All 31 MRI examinations performed after fluoroscopic studies with concentrated barium or iodine solutions were diagnostic for answering the clinical question according to radiologist and report review, regardless of magnet strength and type of fluoroscopic contrast ingested. Magnetic resonance imaging after fluoroscopy had excellent overall image quality (mean score, 4.74/5), minimal to no artifact emanating from bowel (mean, 4.63/5), minimal inhomogeneity artifact (mean, 4.38/5), and excellent diagnostic confidence (mean, 4.98/5). No additional imaging was necessary for diagnosis after MRI. Computed tomography after fluoroscopy had lower overall image quality, more image artifacts, and lower diagnostic confidence (P < 0.05).

CONCLUSIONS

Magnetic resonance imaging is a useful tool for evaluating patients with retained concentrated enteric contrast from recent fluoroscopic examinations. In the absence of contraindication, MRI should be considered in the evaluation of urgent clinical problems in patients who recently underwent a fluoroscopic bowel evaluation.

Epithelial Regeneration Ability of Crohn's Disease Assessed Using Patient-Derived Intestinal Organoids

Little is known about the ability for epithelial regeneration and wound healing in patients with inflammatory bowel diseases. We evaluated the epithelial proliferation and wound healing ability of patients with Crohn's disease (CD) using patient-derived intestinal organoids. Human intestinal organoids were constructed in a three-dimensional intestinal crypt culture of enteroscopic biopsy samples from controls and CD patients. The organoid-forming efficiency of ileal crypts derived from CD patients was reduced compared with those from control subjects (p < 0.001). Long-term cultured organoids (≥6 passages) derived from controls and CD patients showed an indistinguishable microscopic appearance and culturing behavior. Under TNFα-enriched conditions (30 ng/mL), the organoid reconstitution rate and cell viability of CD patient-derived organoids were significantly lower than those of the control organoids (p < 0.05 for each). The number of EdU+ cells was significantly lower in TNFα-treated organoids derived from CD patients than in TNFα-treated control organoids (p < 0.05). In a wound healing assay, the unhealed area in TNFα-treated CD patient-derived organoids was significantly larger than that of TNFα-treated control organoids (p < 0.001). The wound healing ability of CD patient-derived organoids is reduced in TNFα-enriched conditions, due to reduced cell proliferation. Epithelial regeneration ability may be impaired in patients with CD.

Communicating multiple tubular enteric duplication with toxic megacolon in an infant: A case report

RATIONALE

Gastrointestinal tract duplication is a rare congenial anomaly which can be found anywhere along the gastrointestinal tract. While many patients are incidentally diagnosed during operation, in some cases it can present with severe gastrointestinal symptoms. In this case report, the patient presented with signs of toxic megacolon leading to rapid aggravation of inflammatory shock.

PATIENT CONCERNS

A 49-day old male infant presented with fever, poor feeding, and severe abdominal distension.

DIAGNOSIS

Abdominal ultrasonography was done. During the examination, a foley catheter was inserted through the anus to evaluate bowel patency and enable rectal decompression. The tip of the foley catheter was located in a separate narrower tubular lumen adjacent to the distended rectum. These findings suggested possibility of a tubular duplication cyst of the rectum as the culprit for the bowel obstruction.

INTERVENTIONS

The patient underwent emergency laparotomy. Findings showed multiple tubular intestinal duplications involving the ileum, appendix, cecum, descending colon, sigmoid colon and rectum. The true lumen of the rectosigmoid colon was completely collapsed while the adjacent tubular cyst remained severely distended and stool passage was not possible. Decompression of the sigmoid colon was done with loop colostomy with both the wall of the true bowel and enteric cyst forming the colostomy orifice.

OUTCOMES

After 40 days of postoperative care, the patient was discharged with no immediate complications. Four months after the initial operation, colostomy take-down and transanal rectal common wall division was done. No complications were observed.

LESSONS

To our knowledge, this is the first case to be reported where a rare presentation of intestinal duplication resulted in an acute presentation toxic megacolon. Such emergency cases can be effectively treated with emergency surgical bowel decompression and elective common wall division.

Trans-illumination intestine projection imaging of intestinal motility in mice

Functional intestinal imaging holds importance for the diagnosis and evaluation of treatment of gastrointestinal diseases. Currently, preclinical imaging of intestinal motility in animal models is performed either invasively with excised intestines or noninvasively under anesthesia, and cannot reveal intestinal dynamics in the awake condition. Capitalizing on near-infrared optics and a high-absorbing contrast agent, we report the Trans-illumination Intestine Projection (TIP) imaging system for free-moving mice. After a complete system evaluation, we performed in vivo studies, and obtained peristalsis and segmentation motor patterns of free-moving mice. We show the in vivo typical segmentation motor pattern, that was previously shown in ex vivo studies to be controlled by intestinal pacemaker cells. We also show the effects of anesthesia on motor patterns, highlighting the possibility to study the role of the extrinsic nervous system in controlling motor patterns, which requires unanesthetized live animals. Combining with light-field technologies, we further demonstrated 3D imaging of intestine in vivo (3D-TIP). Importantly, the added depth information allows us to extract intestines located away from the abdominal wall, and to quantify intestinal motor patterns along different directions. The TIP system should open up avenues for functional imaging of the GI tract in conscious animals in natural physiological states.

Dose-dependent accumulation of glucose in the intestinal wall and lumen induced by metformin as revealed by 18 F-labelled fluorodeoxyglucose positron emission tomography-MRI

AIM

To investigate the relationships between various clinical variables and the metformin-induced accumulation of fluorodeoxyglucose (FDG) in the intestine, with distinction between the intestinal wall and lumen, in individuals with type 2 diabetes who were receiving metformin treatment and underwent ¹⁸ F-labelled FDG ([¹⁸ F]FDG) positron emission tomography (PET)-MRI.

MATERIALS AND METHODS

We evaluated intestinal accumulation of [¹⁸ F]FDG with both subjective (a five-point visual scale determined by two experienced radiologists) and objective analyses (measurement of the maximum standardized uptake value [SUV_max ]) in 26 individuals with type 2 diabetes who were receiving metformin and underwent [¹⁸ F]FDG PET-MRI. [¹⁸ F]FDG accumulation within the intestinal wall was discriminated from that in the lumen on the basis of SUV_max .

RESULTS

SUV_max for the large intestine was correlated with blood glucose level (BG) and metformin dose, but not with age, body mass index, HbA1c level or estimated glomerular filtration rate (eGFR). SUV_max for the small intestine was not correlated with any of these variables. Visual scale analysis yielded essentially similar results. Metformin dose and eGFR were correlated with SUV_max for the wall and lumen of the large intestine, whereas BG was correlated with that for the wall. Multivariable analysis identified metformin dose as an explanatory factor for SUV_max in the wall and lumen of the large intestine after adjustment for potential confounders including BG and eGFR.

CONCLUSIONS

Metformin dose is an independent determinant of [¹⁸ F]FDG accumulation in the wall and lumen of the large intestine in individuals treated with this drug.

Midgut development in rat embryos using microcomputed tomography

The development of the mammalian gut was first described more than a century ago. Since then, it has been believed that a series of highly orchestrated developmental processes occur before the intestine achieves its final formation. The key steps include the formation of the umbilicus, the so-called "physiological herniation" of the midgut into the umbilical cord, an intestinal "rotation", and the "return of the gut" into the abdominal cavity. However, this sequence of events is predominantly based on histological sections of dissected embryos, a 2D technique with methodological limitations. For a better understanding of spatial relationships in the embryo, we utilized microcomputed tomography (µCT), a nondestructive 3D imaging method. Here, we show the detailed processes and mechanisms of intestinal development in rat embryos, including the development of the umbilicus, the formation of loops inside the umbilical coelom, and the subsequent shift of these loops into the abdominal cavity. Our 3D datasets of developing intestines will substantially advance the understanding of normal mammalian midgut embryology and offer new possibilities to reveal unknown mechanisms in the pathogenesis of congenital disorders.

Management of Crohn Disease: A Review

IMPORTANCE

Crohn disease, a chronic gastrointestinal inflammatory disease, is increasing in incidence and prevalence in many parts of the world. Uncontrolled inflammation leads to long-term complications, including fibrotic strictures, enteric fistulae, and intestinal neoplasia. Therefore, early and effective control of inflammation is of critical importance.

OBSERVATIONS

The optimal management approach for Crohn disease incorporates patient risk stratification, patient preference, and clinical factors in therapeutic decision-making. First-line therapy generally consists of steroids for rapid palliation of symptoms during initiation of anti-tumor necrosis factor α therapy. Other treatments may include monoclonal antibodies to IL-12/23 or integrin α4β7, immunomodulators, combination therapies, or surgery. Effective control of inflammation reduces the risk of penetrating complications (such as intra-abdominal abscesses and fistulae), although more than half of patients will develop complications that require surgery. Adverse reactions to therapy include antibody formation and infusion reactions, infections, and cancers associated with immune modulators and biologics and toxicity to the bone marrow and the liver. Both Crohn disease and corticosteroid use are associated with osteoporosis. Vaccinations to prevent infections, such as influenza, pneumonia, and herpes zoster, are important components of health maintenance for patients with Crohn disease, although live vaccines are contraindicated for patients receiving immune suppression therapy.

CONCLUSIONS AND RELEVANCE

The treatment of patients with Crohn disease depends on disease severity, patient risk stratification, patient preference, and clinical factors, including age of onset and penetrating complications, and includes treatment with steroids, monoclonal antibody therapies, immunomodulators, and surgery. Physicians should be familiar with the advantages and disadvantages of each therapy to best counsel their patients.

Superior Mesenteric Arterial and Venous Thrombosis in COVID-19

Background

Patients with coronavirus disease 2019 (COVID-19) commonly present with fever, constitutional symptoms, and respiratory symptoms. However, atypical presentations are also well known. Though isolated mesenteric arterial occlusion associated with COVID-19 has been reported in literature, combined superior mesenteric arterial and venous thrombosis is rare. We report a case of combined superior mesenteric arterial and venous occlusion associated with COVID-19 infection.

Case Report

We report a case of a 45-year-old man who was a health care worker who presented to the emergency department with severe abdominal pain. The clinical examination was unremarkable, but imaging revealed acute mesenteric ischemia caused by superior mesenteric artery and superior mesenteric vein occlusion. Imaging of the chest was suggestive of COVID-19 infection, which was later confirmed with reverse transcription polymerase chain reaction of his nasopharyngeal swab. To date, only 1 case of combined superior mesenteric artery and superior mesenteric vein thrombosis caused by COVID-19 has been reported.

Why Should an Emergency Physician Be Aware of This?

During the COVID-19 pandemic it is important to keep mesenteric ischemia in the differential diagnosis of unexplained abdominal pain. Routinely adding high-resolution computed tomography of the chest to abdominal imaging should be considered in patients with acute abdomen because it can help to identify COVID-19 immediately. © 2020 Elsevier Inc.

Gastrointestinal Ultrasound (GIUS) in Intestinal Emergencies - An EFSUMB Position Paper

An interdisciplinary group of European experts summarizes the value of gastrointestinal ultrasound (GIUS) in the management of three time-critical causes of acute abdomen: bowel obstruction, gastrointestinal perforation and acute ischemic bowel disease. Based on an extensive literature review, statements for a targeted diagnostic strategy in these intestinal emergencies are presented. GIUS is best established in case of small bowel obstruction. Metanalyses and prospective studies showed a sensitivity and specificity comparable to that of computed tomography (CT) and superior to plain X-ray. GIUS may save time and radiation exposure and has the advantage of displaying bowel function directly. Gastrointestinal perforation is more challenging for less experienced investigators. Although GIUS in experienced hands has a relatively high sensitivity to establish a correct diagnosis, CT is the most sensitive method in this situation. The spectrum of intestinal ischemia ranges from self-limited ischemic colitis to fatal intestinal infarction. In acute arterial mesenteric ischemia, GIUS may provide information, but prompt CT angiography is the gold standard. On the other end of the spectrum, ischemic colitis shows typical ultrasound features that allow correct diagnosis. GIUS here has a diagnostic performance similar to CT and helps to differentiate mild from severe ischemic colitis.

New Oral Coaxial Nanofibers for Gadodiamide-Prospective Intestinal Magnetic Resonance Imaging and Theranostic

PURPOSE

Gadodiamide (GDD) is a widely used magnetic resonance imaging (MRI) contrast agent. It is available only as intravenous injection. Unfortunately, it exhibits a high renal toxicity. In this respect, the author investigated the possibility of developing nanofibers (NFs, one-dimensional (1D) nanostructures) of GDD that would be promising for oral administration in intestinal imaging. NFs are prepared by electrospinning technique in which a strong electrostatic field is applied on a polymer solution.

METHODS

NFs were prepared by coaxial electrospinning technique using Eudragit S100 (ES 100) as a shell layer and GDD loaded with polyvinylpyrrolidone K90 (PVP K90) and hydroxypropyl-beta-cyclodextrin (HP-β-CyD) as core fibers. Compatibility study of the NFs ingredients was attested through ATR and DSC investigations. Thermogravimetric analysis of NFs was done to insure its stability. In vitro release of GDD in the intestinal medium with different pH values was measured. In vitro cytotoxicity test was done to prove its safety. Additionally, stability of NFs to perform its function was examined by X-ray.

RESULTS

NFs experienced high entrapment efficiency of about 94.3% ± 3.1%. The ingredients of NFs were compatible through FT-IR and DSC study. The in vitro release data of GDD from coaxial NFs were slow (˂14%) in pH 1.2 till 2 h, while at pH 7.4 it showed burst release of about 12% in the first 2 min. Thermogravimetric analysis proved the NFs are stable. The in vitro cytotoxicity study proved the safety of NFs. Using mammography, the coaxial NFs behaved the same as GDD plain indicating its ability to be a contrasting agent.

CONCLUSION

Coaxial NFs of GDD as a core with PVP K90 and HP-β-CyD and ES 100 as a shell were stable and efficient as oral imaging dosage form for the intestine. It might be a prospective theranostic.

A PMN-PT Composite-Based Circular Array for Endoscopic Ultrasonic Imaging

Endoscopic ultrasound (EUS), an interventional imaging technology, utilizes a circular array to delineate the cross-sectional morphology of internal organs through the gastrointestinal (GI) track. However, the performance of conventional EUS transducers has scope for improvement because of the ordinary piezoelectric parameters of Pb(Zr, Ti) [Formula: see text] (PZT) bulk ceramic as well as its inferior mechanical flexibility which can cause material cracks during the circular shaping process. To achieve both prominent imaging capabilities and high device reliability, a 128-element 6.8-MHz circular array transducer is developed using a Pb(Mg [Formula: see text]Nb [Formula: see text]) [Formula: see text]-PbTiO₃ (PMN-PT) 1-3 composite with a coefficient of high electromechanical coupling ( [Formula: see text]) and good mechanical flexibility. The characterization results exhibit a large average bandwidth of 58%, a high average sensitivity of 100 mV_pp, and a crosstalk of less than -37 dB near the center frequency. Imaging performance of the PMN-PT composite-based array transducer is evaluated by a wire phantom, an anechoic cyst phantom, and an ex-vivo swine intestine. This work demonstrates the superior performance of the crucial ultrasonic device based on an advanced PMN-PT composite material and may lead to the development of next-generation biomedical ultrasonic devices for clinical diagnosis and treatment.

Diagnostic decision-making tool for imaging term neonatal bowel obstruction

Term neonatal bowel obstruction is common, and absence of treatment is potentially catastrophic. There is a relatively narrow differential diagnosis, with causes categorised as either low or high bowel obstruction. The commonest causes of low bowel obstruction include anorectal malformations (ARM), Hirschsprung's disease, ileal atresia, meconium ileus, meconium plug, and colonic atresia. The commonest causes of high bowel obstruction include duodenal atresia, duodenal stenosis/web, jejunal atresia, and malrotation with volvulus (and hypertrophic pyloric stenosis usually presenting in slightly older infants). Diagnosis can be decided using a step-wise binary decision tool that includes the appropriate imaging steps and evaluation of bowel calibre. This paper presents the decision-making tool from the presenting features, through plain radiographic findings and, where necessary, the additional radiological investigations to assist the general radiologist, novice paediatric radiologist and paediatric surgeon. The tool is pictorial, with the radiological findings accompanied by eight schematics, serving as a simplified visual aid for memorizing the imaging patterns of the differential diagnosis. The imaging and decision-making steps allow for a rapid, simplified diagnosis that can benefit patients by recommending when to perform surgery, when to perform further imaging, and when imaging can act in a therapeutic manner.

Modeling and imaging of intestinal electrical impedance based on conjugate gradient method

Colorectal disease is a digestive tract disease of high incidence worldwide. Its preliminary diagnosis methods such as anal digital diagnosis and enteroscopy are somewhat subjective. Moreover, it is difficult to locate precisely the lesions and their infiltration boundaries for an accurate diagnosis of disease. This study combines endoscope with electrodes placed on the inner wall of the intestine to obtain both the traditional image of the intestine lumen and its electrical impedance tomography (EIT). The spatial impedance distribution image is reconstructed from the data collected by different combination of excitation and detection electrodes. The multidimensional and multiparameter intestinal physiological and pathological changes can thus be analyzed by EIT. This study mainly consists of the following three contributions: (a) construct certain physical models that reflect corresponding characteristics of intestinal tissue and its pathological changes; (b) optimize targeted signal acquisition methods suitable for data processing and analysis of intestinal cavity; and (c) establish a method of image reconstruction that conforms to the morphological characteristics of the intestinal cavity, so that comparative analysis can be applied by using different algorithms for image reconstruction. Through the extraction and analysis of impedance information for intestinal characteristics, we aim to make this tool a supplementary diagnosis method of high sensitivity and specificity for related diseases. This may lay a foundation for more accurate clinical screening of high-risk population, more precise diagnosis and localization of lesion characteristics, and thus better treatment guidance.

Utility of bowel ultrasound in assessing disease activity in Crohn's disease

BACKGROUND

Gastrointestinal ultrasound (GIUS) has been used increasingly for monitoring inflammatory bowel disease (IBD) patients. The aim of this study was to assess the utility of GIUS in assessing disease activity in Crohn's disease (CD).

METHODS

Consecutive patients with CD (diagnosis established for at least 6 months) between July 2017 and July 2018 requiring assessment of disease activity were prospectively assessed by magnetic resonance enterography, colonoscopy (CS), and GIUS within a 2-week period and without any change in ongoing treatment. Features on GIUS which correlated with disease activity were assessed. Sensitivity and specificity of the GIUS in assessing disease activity and localization were calculated.

RESULTS

Thirty-five patients were enrolled in the study. Bowel wall thickness (BWT) ≥ 3 mm and Doppler activity ≥ 2 had the highest sensitivity (100% and 95.6%, respectively) for detecting active disease on CS. BWT ≥ 3 mm had sensitivity, specificity, positive predictive value, and negative predictive value of 100%, 83.3%, 92%, and 100%, respectively for assessing active disease. Combination of median BWT, Doppler activity, and loss of bowel wall stratification correlated with simplified endoscopic score (SES) for CD (r = 0.8, p 0.009) and Harvey-Bradshaw index (HBI, r = 0.76, p 0.04). For localizing active disease in the ileum, GIUS had a sensitivity of 93.7%, 80% for lesions in the right colon, 100% for transverse colon, and 89% for the left colon. Specificity was 100% for ileal and colonic lesions.

CONCLUSION

Loss of stratification, BWT, and Doppler activity in the bowel wall correlate with endoscopic and clinical disease activity in CD. GIUS is a sensitive modality in assessing disease activity in CD.

Fast compressive lens-free tomography for 3D biological cell culture imaging

We present a compressive lens-free technique that performs tomographic imaging across a cubic millimeter-scale volume from highly sparse data. Compared with existing lens-free 3D microscopy systems, our method requires an order of magnitude fewer multi-angle illuminations for tomographic reconstruction, leading to a compact, cost-effective and scanning-free setup with a reduced data acquisition time to enable high-throughput 3D imaging of dynamic biological processes. We apply a fast proximal gradient algorithm with composite regularization to address the ill-posed tomographic inverse problem. Using simulated data, we show that the proposed method can achieve a reconstruction speed ∼10× faster than the state-of-the-art inverse problem approach in 3D lens-free microscopy. We experimentally validate the effectiveness of our method by imaging a resolution test chart and polystyrene beads, demonstrating its capability to resolve micron-size features in both lateral and axial directions. Furthermore, tomographic reconstruction results of neuronspheres and intestinal organoids reveal the potential of this 3D imaging technique for high-resolution and high-throughput biological applications.

Superior Mesenteric Artery Thrombosis and Acute Intestinal Ischemia as a Consequence of COVID-19 Infection

BACKGROUND The novel COVID-19 disease caused by the SARS-CoV-2 virus is a highly infectious disease that originated in Wuhan, China, and has rapidly spread throughout the world. In addition to respiratory complications, the virus has also been implicated in damage to other organ systems as well as coagulopathy. The present report describes the first presumptive case of COVID-19-associated acute superior mesenteric artery thrombosis and acute intestinal ischemia. CASE REPORT A 55-year old man presented to the emergency department with nausea, generalized abdominal pain and diarrhea; he denied having a fever or any respiratory symptoms. Computed tomography (CT) of the abdomen and pelvis revealed bilateral pulmonary ground-glass opacities. He tested positive for SARS-CoV-2, and was treated with hydroxychloroquine, azithromycin and ceftriaxone, and was discharged home after five days of inpatient treatment. One week later, the patient returned with recurrent nausea, vomiting and worsening diffuse abdominal pain. A CT scan of the abdomen showed a 1.6-cm clot, causing high grade narrowing of the proximal superior mesenteric artery and bowel ischemia. The patient emergently underwent exploratory laparotomy, thromboembolectomy and resection of the ischemic small bowel. A post-operative complete hypercoagulable workup was unrevealing. CONCLUSIONS Despite the absence of respiratory symptoms, patients infected with SARS-CoV-2 may show atypical presentations, such as gastrointestinal symptoms. Clinicians managing patients with suspected or confirmed SARS-CoV-2 infection during the COVID-19 pandemic should monitor these patients for potential complications that may arise from this disease.