Assessment of small bowel motility in patients with chronic intestinal pseudo-obstruction using cine-MRI

Quantitative Analysis of Small Intestinal Motility in 3D Cine-MRI Using Centerline-Aware Motion Estimation

BACKGROUND

Currently available tools for noninvasive motility quantification of the small intestine are limited to dynamic 2D MRI scans, which are limited in their ability to differentiate between types of intestinal motility.

PURPOSE

To develop a method for quantification and characterization of small intestinal motility in 3D, capable of differentiating motile, non-motile and peristaltic motion patterns.

STUDY TYPE

Prospective.

SUBJECTS

Fourteen healthy volunteers (127 small intestinal segments) and 10 patients with Crohn's disease (87 small intestinal segments).

FIELD STRENGTH/SEQUENCE

3.0 T, 3D balanced fast field echo sequence, 1 volume per second.

ASSESSMENT

Using deformable image registration between subsequent volumes, the local velocity within the intestinal lumen was quantified. Average velocity and average absolute velocity along intestinal segments were used with linear classifiers to differentiate motile from non-motile intestines, as well as erratic motility from peristalsis. The mean absolute velocity of small intestinal content was compared between healthy volunteers and Crohn's disease patients, and the discriminative power of the proposed motility metrics for detecting motility and peristalsis was determined. The consensus of two observers was used as referenced standard.

STATISTICAL TESTS

Student's t-test to assess differences between groups; area under the receiver operating characteristic curve (AUC) to assess discriminative ability. P < 0.001 was considered significant.

RESULTS

A significant difference in the absolute velocity of intestinal content between Crohn's patients and healthy volunteers was observed (median [IQR] 1.06 [0.61, 1.56] mm/s vs. 1.84 [1.37, 2.43] mm/s), which was consistent with manual reference annotations of motile activity. The proposed method had a strong discriminative performance for detecting non-motile intestines (AUC 0.97) and discernible peristalsis (AUC 0.81).

DATA CONCLUSION

Analysis of 3D cine-MRI using centerline-aware motion estimation has the potential to allow noninvasive characterization of small intestinal motility and peristaltic motion in 3D.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.

Chronic intestinal pseudo-obstruction in adults: A practical guide to identify patient subgroups that are suitable for more specific treatments

Chronic intestinal pseudo-obstruction is a rare and heterogeneous syndrome characterized by recurrent symptoms of intestinal obstruction with radiological features of dilated small or large intestine with air/fluid levels in the absence of any mechanical occlusive lesion. Several diseases may be associated with chronic intestinal pseudo-obstruction and in these cases, the prognosis and treatment are related to the underlying disease. Also, in its "primary or idiopathic" form, two subgroups of patients should be determined as they require a more specific therapeutic approach: patients whose chronic intestinal pseudo-obstruction is due to sporadic autoimmune/inflammatory mechanisms and patients whose neuromuscular changes are genetically determined. In a context of a widely heterogeneous adult population presenting chronic intestinal pseudo-obstruction, this review aims to summarize a practical diagnostic workup for identifying definite subgroups of patients who might benefit from more specific treatments, based on the etiology of their underlying condition.

Imaging in pediatric disorders of the gut-brain interactions: current best practice and future directions

INTRODUCTION

Disorders of Gut-Brain Interactions (DGBI) are a common clinical problem in children and pose significant challenges to the attending pediatrician. Radiological investigations are commonly ordered to evaluate these children.

AREA COVERED

This review focuses on the current best practice of using radiological investigations in DGBIs and how novel radiological investigations could revolutionize the assessment and therapeutic approach of DGBI in children.

EXPERT OPINION

We believe imaging in DGBI is still in its early stages, but it has the potential to revolutionize how we diagnose and treat children with DGBI. As the understanding of the gut-brain axis continues to grow, we can expect to see the disappearance of conventional imaging techniques and the emergence of more sophisticated imaging techniques with less radiation exposure in the future which provide more clinically meaningful information regarding the gut-brain axis and its influence on intestinal function. Some of the novel imaging modalities will be able to broaden our horizon of understanding DGBI in children providing more useful therapeutic options to minimize their suffering.

Enteroscopy versus Video Capsule Endoscopy for Automatic Diagnosis of Small Bowel Disorders-A Comparative Analysis of Artificial Intelligence Applications

BACKGROUND

Small bowel disorders present a diagnostic challenge due to the limited accessibility of the small intestine. Accurate diagnosis is made with the aid of specific procedures, like capsule endoscopy or double-ballon enteroscopy, but they are not usually solicited and not widely accessible. This study aims to assess and compare the diagnostic effectiveness of enteroscopy and video capsule endoscopy (VCE) when combined with artificial intelligence (AI) algorithms for the automatic detection of small bowel diseases.

MATERIALS AND METHODS

We performed an extensive literature search for relevant studies about AI applications capable of identifying small bowel disorders using enteroscopy and VCE, published between 2012 and 2023, employing PubMed, Cochrane Library, Google Scholar, Embase, Scopus, and ClinicalTrials.gov databases.

RESULTS

Our investigation discovered a total of 27 publications, out of which 21 studies assessed the application of VCE, while the remaining 6 articles analyzed the enteroscopy procedure. The included studies portrayed that both investigations, enhanced by AI, exhibited a high level of diagnostic accuracy. Enteroscopy demonstrated superior diagnostic capability, providing precise identification of small bowel pathologies with the added advantage of enabling immediate therapeutic intervention. The choice between these modalities should be guided by clinical context, patient preference, and resource availability. Studies with larger sample sizes and prospective designs are warranted to validate these results and optimize the integration of AI in small bowel diagnostics.

CONCLUSIONS

The current analysis demonstrates that both enteroscopy and VCE with AI augmentation exhibit comparable diagnostic performance for the automatic detection of small bowel disorders.

Technical Feasibility of Quantitative Measurement of Various Degrees of Small Bowel Motility Using Cine Magnetic Resonance Imaging

OBJECTIVE

Cine magnetic resonance imaging (MRI) has emerged as a noninvasive method to quantitatively assess bowel motility. However, its accuracy in measuring various degrees of small bowel motility has not been extensively evaluated. We aimed to draw a quantitative small bowel motility score from cine MRI and evaluate its performance in a population with varying degrees of small bowel motility.

MATERIALS AND METHODS

A total of 174 participants (28.5 ± 7.6 years; 135 males) underwent a 22-second-long cine MRI sequence (2-dimensional balanced turbo-field echo; 0.5 seconds per image) approximately 5 minutes after being intravenously administered 10 mg of scopolamine-N-butyl bromide to deliberately create diverse degrees of small bowel motility. In a manually segmented area of the small bowel, motility was automatically quantified using a nonrigid registration and calculated as a quantitative motility score. The mean value (MV) of motility grades visually assessed by two radiologists was used as a reference standard. The quantitative motility score's correlation (Spearman's ρ) with the reference standard and performance (area under the receiver operating characteristics curve [AUROC], sensitivity, and specificity) for diagnosing adynamic small bowel (MV of 1) were evaluated.

RESULTS

For the MV of the quantitative motility scores at grades 1, 1.5, 2, 2.5, and 3, the mean ± standard deviation values were 0.019 ± 0.003, 0.027 ± 0.010, 0.033 ± 0.008, 0.032 ± 0.009, and 0.043 ± 0.013, respectively. There was a significant positive correlation between the quantitative motility score and the MV (ρ = 0.531, P < 0.001). The AUROC value for diagnosing a MV of 1 (i.e., adynamic small bowel) was 0.953 (95% confidence interval, 0.923-0.984). Moreover, the optimal cutoff for the quantitative motility score was 0.024, with a sensitivity of 100% (15/15) and specificity of 89.9% (143/159).

CONCLUSION

The quantitative motility score calculated from a cine MRI enables diagnosis of an adynamic small bowel, and potentially discerns various degrees of bowel motility.

Magnetic Resonance Imaging of the Gastrointestinal Tract: Current Role, Recent Advancements and Future Prospectives

This review focuses on the role of magnetic resonance imaging (MRI) in the evaluation of the gastrointestinal tract (GI MRI), analyzing the major technical advances achieved in this field, such as diffusion-weighted imaging, molecular imaging, motility studies, and artificial intelligence. Today, MRI performed with the more advanced imaging techniques allows accurate assessment of many bowel diseases, particularly inflammatory bowel disease and rectal cancer; in most of these diseases, MRI is invaluable for diagnosis, staging, and disease monitoring under treatment. Several MRI parameters are currently considered activity biomarkers for inflammation and neoplastic disease. Furthermore, in younger patients with acute or chronic GI disease, MRI can be safely used for short-term follow-up studies in many critical clinical situations because it is radiation-free. MRI assessment of functional gastro-esophageal and small bowel disorders is still in its infancy but very promising, while it is well established and widely used for dynamic assessment of anorectal and pelvic floor dysfunction; MRI motility biomarkers have also been described. There are still some limitations to GI MRI related to high cost and limited accessibility. However, technical advances are expected, such as faster sequences, more specific intestinal contrast agents, AI analysis of MRI data, and possibly increased accessibility to GI MRI studies. Clinical interest in the evaluation of bowel disease using MRI is already very high, but is expected to increase significantly in the coming years.

Imaging Review of Gastrointestinal Motility Disorders

The motor function of the gastrointestinal tract relies on the enteric nervous system, which includes neurons spanning from the esophagus to the internal anal sphincter. Disorders of gastrointestinal motility arise as a result of disease within the affected portion of the enteric nervous system and may be caused by a wide array of underlying diseases. The etiology of motility disorders may be primary or due to secondary causes related to infection or inflammation, congenital abnormalities, metabolic disturbances, systemic illness, or medication-related side effects. The symptoms of gastrointestinal dysmotility tend to be nonspecific and may cause diagnostic difficulty. Therefore, evaluation of motility disorders requires a combination of clinical, radiologic, and endoscopic or manometric testing. Radiologic studies including fluoroscopy, CT, MRI, and nuclear scintigraphy allow exclusion of alternative pathologic conditions and serve as adjuncts to endoscopy and manometry to determine the appropriate diagnosis. Additionally, radiologist understanding of clinical evaluation of motility disorders is necessary for guiding referring clinicians and appropriately imaging patients. New developments and advances in imaging techniques have allowed improved assessment and diagnosis of motility disorders, which will continue to improve patient treatment options. Online supplemental material is available for this article. ^©RSNA, 2022.

Changing Flows Balance Nutrient Absorption and Bacterial Growth along the Gut

Small intestine motility and its ensuing flow of luminal content impact both nutrient absorption and bacterial growth. To explore this interdependence we introduce a biophysical description of intestinal flow and absorption. Rooted in observations of mice we identify the average flow velocity as the key control of absorption efficiency and bacterial growth, independent of the exact contraction pattern. We uncover self-regulation of contraction and flow in response to nutrients and bacterial levels to promote efficient absorption while restraining detrimental bacterial overgrowth.

Impact of bowel dilation on small bowel motility measurements with cine-MRI: assessment of two quantification techniques

Objectives

To evaluate the effect of bowel dilation on cine-MRI small bowel motility measurements, by comparing a conventional motility score (including bowel wall and lumen) with a bowel wall-specific motility score in healthy and diseased populations.

Methods

Four populations were included: 10 Crohn's patients with a stricture and prestricture dilation for segmental motility analysis, and 14 mannitol-prepared healthy subjects, 15 fasted healthy subjects and eight chronic intestinal pseudo-obstruction (CIPO) patients (characterized by dilated bowel loops) for global small bowel motility analysis. All subjects underwent a cine-MRI scan from which two motility scores were calculated: a conventional score (including bowel wall and lumen) and a bowel wall-specific score. The difference between the two scores was calculated per population and compared between groups with a one-way ANOVA and Tukey-Kramer analysis.

Results

In Crohn's patients, the median (IQR) change between the conventional and wall-specific motility score was 0% (-2 to +4%) within the stricture and 0% (-1 to +7%) in the prestricture dilation. For the global small bowel, this was -1% (-5 to 0%) in mannitol-prepared healthy subjects, -2% (-6 to +2%) in fasted healthy subjects and +14% (+6 to+20%) in CIPO patients. The difference between the two motility scores in CIPO patients differed significantly from the four other groups (p = 0.002 to p < 0.001).

Conclusions

The conventional small bowel motility score seems robust in Crohn's disease patients and healthy subjects. In patients with globally and grossly dilated bowel loops, a bowel-wall specific motility score may give a better representation of small bowel motility.

Advances in knowledge

These findings support researchers and clinicians with making informed choices for using cine-MRI motility analysis in different populations.

Pediatric Intestinal Pseudo-Obstruction: Progress and Challenges

BACKGROUND

Chronic intestinal pseudo-obstruction is a rare disorder and represents the most severe form of gastrointestinal dysmotility with significant morbidity and mortality. Emerging research shows considerable differences between the adult and pediatric population with intestinal pseudo-obstruction and the term Pediatric Intestinal Pseudo-Obstruction (PIPO) was recently proposed.

PURPOSE

The aim of this article is to provide pediatric gastroenterologists and pediatricians with an up to date review of the etiology and underlining pathophysiology, clinical features, diagnostic and management approaches currently available for PIPO and to discuss future perspectives for the diagnosis and management of this rare disease.

New cine magnetic resonance imaging parameters for the differential diagnosis of chronic intestinal pseudo-obstruction

Chronic intestinal pseudo-obstruction (CIPO) is a severe and refractory intestinal motility disorder whose diagnosis currently relies on subjective imaging assessments. Cine magnetic resonance imaging (MRI) may potentially improve the quantitative analysis of gastrointestinal motility; however, suitable CIPO detection parameters should be determined. Cine MRI was performed in seven patients with CIPO and 11 healthy controls. The logarithm of the Mahalanobis distance (x₁) and distance variation per time (x₂) were used as the original parameters to determine CIPO diagnostic thresholds. Furthermore, the correlation between cine MRI findings and CIPO severity was investigated. Threshold values of α = 1.10 and β = 0.15 for x₁ and x₂, respectively, produced a CIPO diagnosis sensitivity of 1.00 (7/7) and specificity of 0.82 (9/11). The resulting error was 0.11 (2/18). The two parameters were correlated (Pearson's correlation coefficient: - 0.52). Any of the intestinal tracts of patients with severe CIPO requiring home parenteral nutrition belonged to the region defined by x₁ ≥ 1.10 and x₂ ≤ 0.15. Cine MRI is effective for the quantitative evaluation of small intestinal motility and CIPO diagnosis when using the abovementioned parameters and can be useful for treatment decision-making. However, these parameters have a wide distribution in healthy volunteers; this may complicate the detection of other disorders.

Esophageal High-Resolution Manometry for Diagnosing the Severity of the Chronic Intestinal Pseudo-Obstruction: A Case Series

BACKGROUND

Chronic intestinal pseudo-obstruction (CIPO) is a severe and refractory intestinal motility disorder. However, due to its rarity and difficult histological investigation, its pathophysiology has not been characterized.

AIM

Therefore, in this study, we aimed to determine the role of esophageal high-resolution manometry (HRM) in CIPO and the histological and clinical characteristics of the disease.

METHODS

Patients with CIPO were analyzed for clinical characteristics; histological findings; and clinical courses after therapeutic intervention. In addition, HRM was performed to determine the esophageal involvement.

RESULTS

Eleven patients were diagnosed with CIPO, and five required the long period of parenteral nutrition showing impaired esophageal motility including achalasia and absent contractility diagnosed with HRM. The four of these five cases showed acute onset of the CIPO following the triggering events of pregnancy, appendicitis, and surgery. In contrast, other six patients with normal or Jackhammer esophagus on HRM had moderate severity of CIPO with gradual onset. The histological analyses revealed that the loss of the intestinal neural ganglion cells and layers by inflammation, destruction, and atrophy are related to the severity of the clinical course of the disease and esophageal HRM findings of achalasia and absent contractility.

CONCLUSIONS

HRM may be useful to diagnose the severity of the clinical course and to determine the therapeutic options for CIPO.

Fasted and fed small bowel motility patterns at cine-MRI in chronic intestinal pseudo-obstruction

BACKGROUND

Chronic intestinal pseudo-obstruction (CIPO) is a severe intestinal motility disorder of which the pathophysiology is largely unknown. This study aimed at gaining insight in fasted and fed small bowel motility in CIPO patients using cine-MRI with caloric stimulation.

METHODS

Eight adult patients with manometrically confirmed CIPO were prospectively included. Patients underwent a cine-MRI protocol after an overnight fast, comprising fasting-state scans and scans after ingestion of a meal (Nutridrink, 300 kcal). Small bowel motility was quantified resulting in a motility score in arbitrary units (AU) and visually assessed by three radiologists. Findings were compared with those in 16 healthy volunteers.

KEY RESULTS

Motility scores (median, IQR) in CIPO patients were 0.21 (0.15-0.30) in the fasting state and 0.23 (0.15-0.27) directly postprandially. In healthy volunteers, corresponding motility scores were 0.15 (0.13-0.18) and 0.22 (0.19-0.25), respectively. The postprandial change in motility score was +1% (-19 to +21%) in CIPO and +39% (+23 to +50%) in healthy volunteers (p = 0.001*). Visual analysis revealed increased small bowel contractility in four, normal in two, and decreased in two CIPO patients.

CONCLUSIONS & INFERENCES

Surprisingly, we found hyperactive small bowel motility in half of the CIPO patients, suggestive of uncoordinated motility. A wide variation in motility patterns was observed, both higher, lower, and comparable contractility compared with healthy subjects. No clear postprandial activation was seen in patients. Cine-MRI helps to gain insight in this complex disease and can potentially impact treatment decisions in the future.

A 3D cine-MRI acquisition technique and image analysis framework to quantify bowel motion demonstrated in gynecological cancer patients

PURPOSE

Magnetic resonance imaging (MRI) is increasingly used in radiation oncology for target delineation and radiotherapy treatment planning, for example, in patients with gynecological cancers. As a consequence of pelvic radiotherapy, a part of the bowel is irradiated, yielding risk of bowel toxicity. Existing dose-effect models predicting bowel toxicity are inconclusive and bowel motion might be an important confounding factor. The exact motion of the bowel and dosimetric effects of its motion are yet uncharted territories in radiotherapy. In diagnostic radiology methods on the acquisition of dynamic MRI sequences were developed for bowel motility visualization and quantification. Our study aim was to develop an imaging technique based on three-dimensional (3D) cine-MRI to visualize and quantify bowel motion and demonstrate it in a cohort of gynecological cancer patients.

METHODS

We developed an MRI acquisition suitable for 3D bowel motion quantification, namely a balanced turbo field echo sequence (TE = 1.39 ms, TR = 2.8 ms), acquiring images in 3.7 s (dynamic) with a 1.25 × 1.25 × 2.5 mm³ resolution, yielding a field of view of 200 × 200 × 125 mm³ . These MRI bowel motion sequences were acquired in 22 gynecological patients. During a 10-min scan, 160 dynamics were acquired. Subsequent dynamics were deformably registered using a B-spline transformation model, resulting in 159 3D deformation vector fields (DVFs) per MRI set. From the 159 DVFs, the average vector length was calculated per voxel to generate bowel motion maps. Quality assurance was performed on all 159 DVFs per MRI, using the Jacobian Determinant and the Harmonic Energy as deformable image registration error metrics. In order to quantify bowel motion, we introduced the concept of cumulative motion-volume histogram (MVH) of the bowel bag volume. Finally, interpatient variation of bowel motion was analyzed using the MVH parameters M10%, M50%, and M90%. The M10%/M50%/M90% represents the minimum bowel motion per frame of 10%/50%/90% of the bowel bag volume.

RESULTS

The motion maps resulted in a visualization of areas with small and large movements within the bowel bag. After applying quality assurance, the M10%, M50%, and M90% were 4.4 (range 2.2-7.6) mm, 2.2 (range 0.9-4.1) mm, and 0.5 (range 0.2-1.4) mm per frame, on average over all patients, respectively.

CONCLUSION

We have developed a method to visualize and quantify 3D bowel motion with the use of bowel motion specific MRI sequences in 22 gynecological cancer patients. This 3D cine-MRI-based quantification tool and the concept of MVHs can be used in further studies to determine the effect of radiotherapy on bowel motion and to find the relation with dose effects to the small bowel. In addition, the developed technique can be a very interesting application for bowel motility assessment in diagnostic radiology.

Simultaneous assessment of colon motility in children with functional constipation by cine-MRI and colonic manometry: a feasibility study

BACKGROUND

Colonic manometry is the current reference standard for assessing colonic neuromuscular function in children with intractable functional constipation (FC). Recently, cine magnetic resonance imaging (cine-MRI) has been proposed as a non-invasive alternative. We compared colonic motility patterns on cine-MRI with those obtained by manometry in children, by stimulating high-amplitude propagating contractions (HAPCs) with bisacodyl under manometric control while simultaneously acquiring cine-MRI.

METHODS

After Institutional Review Board approval, adolescents with FC scheduled to undergo colonic manometry were included. A water-perfused 8-lumen catheter was used for colonic manometry recordings. After an intraluminal bisacodyl infusion, cine-MRI sequences of the descending colon were acquired for about 30 min simultaneously with colonic manometry. Manometry recordings were analysed for HAPCs. MRI images were processed with spatiotemporal motility MRI techniques. The anonymised motility results of both techniques were visually compared for the identification of HAPCs in the descending colon.

RESULTS

Data regarding six patients (three males) were analysed (median age 14 years, range 12-17). After bisacodyl infusion, three patients showed a total of eleven HAPCs with colonic manometry. Corresponding cine-MRI recorded high colonic activity during two of these HAPCs, minimal activity during seven HAPCs, while two HAPCs were not recorded. In two of three patients with absent HAPCs on manometry, colonic activity was recorded with cine-MRI.

CONCLUSIONS

Simultaneous acquisition of colonic cine-MRI and manometry in children with FC is feasible. Their motility results did not completely overlap in the identification of HAPCs. Research is needed to unravel the role of cine-MRI in this setting.

Could Chronic Idiopatic Intestinal Pseudo-Obstruction Be Related to Viral Infections?

Chronic idiopathic intestinal pseudo-obstruction (CIIPO) is a disease characterized by symptoms and signs of small bowel obstruction in the absence of displayable mechanical obstruction. Due to the known neuropathic capacity of several viruses, and their localization in the intestine, it has been hypothesized that such viruses could be involved in the pathogenesis of CIIPO. The most frequently involved viruses are John Cunningham virus, Herpesviridae, Flaviviruses, Epstein–Barr virus and Citomegalovirus. Therefore, the present narrative review aims to sum up some new perspectives in the etiology and pathophysiology of CIIPO.

Radiological evaluation of a case of chronic intestinal pseudo-obstruction (CIPO)

Chronic intestinal pseudo-obstruction (CIPO) is a severe form of gastrointestinal dysmotility (often due to derangement of the innervation and/or smooth muscle and/or interstitial cells of Cajal) with recurrent episodes of intestinal sub-occlusion. We describe a clinical setting and radiological features of CIPO in an 11-year-old girl with periodic relapses. Our attention was focused firstly on surgical causes, leading to a delay in the diagnosis; thus, is important detecting equivocal symptoms and considering the possible correlation to the CIPO for an early diagnosis and related prevention of acute episodes improving prognosis and quality of life of pediatric patients.

An international survey on clinicians' perspectives on the diagnosis and management of chronic intestinal pseudo-obstruction and enteric dysmotility

BACKGROUND

Chronic intestinal pseudo-obstruction (CIPO) and enteric dysmotility (ED) are small intestinal motility disorders defined by radiological and manometric criteria. In the absence of consensus guidelines, we surveyed opinions on the diagnosis and management of CIPO and ED among experts from different countries.

METHODS

A survey questionnaire was circulated electronically to members of the European society for Clinical Nutrition and Metabolism, European Society of Neurogastroenterology and Motility, and United European Gastroenterology. Only responses from participants completing all required components were included.

KEY RESULTS

Of 154 participants, 93% agreed that CIPO and ED should be classified separately. Overall, 73% reported an increasing incidence of CIPO and ED, with hypermobile Ehlers-Danlos Syndrome the group with the largest increase in referrals (37%), particularly in the UK (P < .0001). The majority (95%) find diagnosing CIPO and ED difficult. Notably, antroduodenal manometry, a test mandated to diagnose ED, is infrequently used (only 21% respondents use in >50% cases) and full thickness biopsies were reported to seldom influence medical treatment, nutritional management, and prognosis. Respondents reported that very few treatments are useful for most patients, with bacterial overgrowth treatment, prucalopride, and psychological therapies felt to be the most useful. While only 23% of clinicians felt that parenteral nutrition (PN) improves gastrointestinal symptoms in >50% of cases, 68% reported PN dependency at 5 years in the majority of cases.

CONCLUSIONS AND INFERENCES

These data highlight the difficulties with diagnosing and managing CIPO and ED and underscore the urgent need for international, multidisciplinary, clinical practice guidelines.

Cine magnetic resonance urography for postoperative evaluation of reconstructive urinary tract after ileal ureter substitution: initial experience

AIM

To report the initial experiences with functional cine magnetic resonance urography (cine MRU) and assess its usefulness as a novel postoperative evaluation method of ileal ureter substitution.

MATERIALS AND METHODS

The medical records of 17 patients from who underwent cine MRU during June 2010 to December 2019 during their follow-up after ileal ureter substitution were collected. The cine MRU videos of reconstructive urinary tract were observed, and the luminal diameter, contraction ratio, peristaltic waves, and ureteral jets were measured.

RESULTS

Seventeen patients underwent cine MRU after ileal ureter substitution during their follow-up. Based on their cine MRU videos assessing the morphology and the peristaltic motility of the reconstructive urinary tract, there was resolution of preoperative hydronephrosis, which matched their ameliorative renal function. Clearly, peristaltic motility of the ileal graft was observed in 14 patients with obvious peristaltic waves and ureteral jets.

CONCLUSION

This study is the first to assess the clinical utility of functional cine MRU during the patient follow-up after ileal ureter substitution. Cine MRU is a radiation-free, non-invasive imaging method that can clearly show the morphology and the peristaltic motility of the ileal graft. Therefore, cine MRU, as a novel technique, will be extremely useful in the postoperative evaluation of patients after ileal ureter substitution.

Small Bowel Dysmotility, Pseudoobstruction, and Functional Correlation with Histopathology: Lessons Learned

PURPOSE OF REVIEW

Small bowel dysmotility is a broad heterogeneous term that encompasses a wide range of gastrointestinal disorders resulting from abnormal gut motility. Chronic intestinal pseudo-obstruction (CIPO) is a severe, rare, and complex small bowel motility disorder at the extreme end of this spectrum. It is characterized by failure of the intestinal tract to propel contents, which results in signs and symptoms of bowel obstruction albeit in the absence of any obstructive lesion(s). In this article, we discuss up-to-date diagnostic techniques, management options, and histopathological findings in CIPO.

RECENT FINDINGS

We will emphasize the latest diagnostic methodologies and therapeutic options as well as enteric histopathologic abnormalities in patients with CIPO. CIPO continues to be a clinical challenge. Several novel pharmacological agents hold promise including gastrointestinal hormone agonists and prokinetics. Furthermore, histopathologic findings may help guide therapy and provide further prognostic significance. At present, nutritional support, symptom management, and avoidance of long-term complications are the mainstay of treatment in CIPO.

A Systematic Review of Technical Parameters for MR of the Small Bowel in non-IBD Conditions over the Last Ten Years

Technical guidelines for magnetic resonance imaging (MRI) of the small bowel (SB) in the setting of inflammatory bowel diseases (IBDs) were detailed in a 2017 consensus issued by European Society of Gastrointestinal and Abdominal Radiology (ESGAR) and European Society of Pediatric Radiology (ESPR); however, MRI for non-IBD conditions was not addressed. Hence, we performed a systematic review collecting researches on SB MRI for non-IBDs. The literatures were then divided into morphologic group and functional group. Information about the MRI techniques, gastrointestinal preparation, and details of cine-MRI protocols was extracted. We found that a 1.5 T MRI system, prone positioning, and MR enterography were frequently utilized in clinical practice. Gadolinium contrast sequences were routinely implemented, while diffusion-weighted imaging (DWI) was much less performed. The gastrointestinal preparation varied throughout the studies. No uniform protocols for cine imaging could be established. SB MRI examinations for non-IBDs are far from standardized, especially for functional studies. Recommendations for standard parameters in cine-MRI sequences are difficult to make due to lack of evidentiary support. MRI investigations in non-IBD conditions are needed and the standardization of non-IBD imaging in clinical practice is required.

Spatio-temporal motility MRI analysis of the stomach and colon

BACKGROUND

MRI is increasingly used to objectively assess gastrointestinal motility. However, motility metrics often do not offer insights into the nature of contractile action. This study introduces a systematic method of making spatio-temporal measurements of contractions, based on changes in bowel lumen diameter.

METHODS

Two heterogeneous cohorts of subjects were selected displaying gastric (n = 15) and colonic motility (n = 20) on which to test the spatio-temporal motility MRI (STMM) technique. STMM involved delineating the bowel lumen along with inner and outer bowel wall along a section of the gastrointestinal tract. A series of diameter measurements were made automatically across the central axis of the lumen. Measurements were automatically propagated through the time series using a previously validated algorithm. Contractions were quantitatively summarized with two methods measuring (a) normalized contraction plot (NCP) and (b) combined velocity distance (CVD) both of which can be visualized as spatio-temporal motility maps. Both metrics were correlated against subjective visual scoring systems.

KEY RESULTS

Good correlation was seen between reader scores and both motility metrics (NCP, R = 0.85, P < 0.001, CVD, R = 0.93, R < 0.001) in the gastric data. Good correlation was also seen between the reader scores and the two metrics in the colonic data (NCP, R = 0.82, P < 0.001, CVD, R = 0.78, R < 0.001).

CONCLUSIONS AND INFERENCES

Spatio-temporal motility MRI analysis of the stomach and colon correlates well with reader scores in a range of datasets and provides both a quantitative and qualitative means of assessing contractile activity in the gastrointestinal tract.

Detecting the effects of a standardized meal challenge on small bowel motility with MRI in prepared and unprepared bowel

OBJECTIVE

MRI is increasingly used to evaluate small bowel contractility. The objective of this study was to validate a clinically practical stimulation test (300-kcal meal) for small bowel motility.

METHODS

Thirty-one healthy subjects underwent dynamic MRI to capture global small bowel motility after ±10h fasting, of which 15 underwent bowel preparation consisting of 1 L 2.5% mannitol solution and 16 did not. Each subject underwent (1) a baseline motility scan (2) a food challenge (3) a post-challenge scan, and (4) second post-challenge scan (after ±20 minutes). This protocol was repeated within 2 weeks. Motility was quantified using a validated motility assessment technique.

KEY RESULTS

Motility in prepared subjects at baseline was significantly higher than motility in unprepared subjects (0.36 AU vs 0.18 AU, P < 0.001). In the prepared group, the food challenge produced an 8% increase in motility (P = 0.33) while in the unprepared subjects a significant increase of 30% was observed (P < 0.001). Responses to food remained insignificant (P = 0.21) and significant (P = 0.003), for the prepared and unprepared subjects, respectively, ±20 minutes post food challenge. These results were confirmed in the repeated scan session.

CONCLUSION & INFERENCES

A significant response to a 300-kcal meal was measured within 10 minutes in unprepared bowel, supporting the clinical use of this challenge to provoke and assess motility changes. A caloric challenge did not produce an observable increase in motility in mannitol prepared subjects.

Will MRI of gastrointestinal function parallel the clinical success of cine cardiac MRI?

Cine cardiac MRI is generally accepted as the "gold-standard" for functional myocardial assessment. It only took a few years after the development of commercial MRI systems for functional cardiac imaging to be developed, with electrocardiogram (ECG)-gated cine imaging first reported in 1988. The function of the gastrointestinal (GI) tract is more complex to study compared to the heart. However, the idea of having a non-invasive tool to study the GI function that also allows the concurrent assessment of different aspects of this function has become more and more attractive in the gastroenterological field. This review summarises key literature of the last 5 years to describe the current status of MRI in respect to the evaluation of GI function, highlighting the gaps and challenges and the future prospects. As the clinical application of a new technique requires that its clinical utility is confirmed by demonstration of its ability to enable clinicians to make a diagnosis and/or predict the treatment response, this review also considers whether or not this has been achieved, and how MRI has been validated against techniques currently recognised as the gold standard in clinical practice.

Cine MRI assessment of motility in the unprepared small bowel in the fasting and fed state: Beyond the breath-hold

BACKGROUND

The symptoms of functional bowel disorders are common in postprandial but investigations are generally undertaken in the fasted state using invasive procedures. MRI provides a noninvasive tool to study the gastrointestinal tract in an unperturbed, fed state. The aim of this study was to develop a technique to assess small bowel motility from cine MRI data in the unprepared bowel in fasting and fed states.

METHODS

Fifteen healthy volunteers underwent a baseline MRI scan after which they consumed a 400 g soup. Subjects then underwent a postprandial scan followed by further scans at regular intervals. Small bowel motility was assessed using single-slice bTFE cine MRI. An optimized processing technique was used to generate motility data based on power spectrum analysis of voxel-signal changes with time. Interobserver variability (n = 15) and intra-observer (n = 6) variability were assessed. Changes in the motility index were compared between fasted and immediate postprandial state.

KEY RESULTS

Excellent agreement between observers was seen across the range of motility measurements acquired, with intraclass correlation coefficient (ICC) of 0.979 (P < 0.0001) and Bland-Altman limits of agreement 95% CI: -28.9 to 45.9 au. Intra-observer variability was low with ICC of 0.992 and 0.960 (2 observers, P < 0.0001). Changes from the fasted to immediately postprandial state showed an average increase of 122.4% ± 98.7% (n = 15).

CONCLUSIONS & INFERENCES

This optimized technique showed excellent inter and intra observer agreement. It was sensitive to changes in motility induced feeding. This technique will be useful to study contractile activity and regional patterns along the gastrointestinal tract under physiological conditions.

The evolution of magnetic resonance enterography in the assessment of motility disorders in children

Gastrointestinal symptoms including constipation, diarrhoea, pain and bloating represent some of the most common clinical problems for patients. These symptoms can often be managed with cheap, widely available medication or will spontaneously resolve. However, for many patients, chronic GI symptoms persist and frequently come to dominate their lives. At one end of the spectrum there is Inflammatory Bowel Disease (IBD) with a clearly defined but expensive treatment pathway. Contrasting with this is Irritable Bowel Syndrome (IBS), likely a collection of pathologies, has a poorly standardised pathway with unsatisfactory clinical outcomes. Managing GI symptoms in adult populations is a challenge. The clinical burden of gastrointestinal disease is also prevalent in paediatric populations and perhaps even harder to treat. In this review we explore some of the recent advances in magnetic resonance imaging (MRI) to study the gastrointestinal tract. Complex in both its anatomical structure and its physiology we are likely missing key physiological markers of disease through relying on symptomatic descriptors of gut function. Using MRI we might be able to characterise previously opaque processes, such as non-propulsive contractility, that could lead to changes in how we understand even common symptoms like constipation. This review explores recent advances in the field in adult populations and examines how this safe, objective and increasingly available modality might be applied to paediatric populations.

Pathophysiology, Diagnosis, and Management of Chronic Intestinal Pseudo-Obstruction

Chronic intestinal pseudo-obstruction (CIPO) is a rare disorder characterized by an impairment of coordinated propulsive activity in the gastrointestinal (GI) tract, which clinically mimics mechanical intestinal obstruction. CIPO is the most severe and debilitating form of GI dysmotility. CIPO may be primary or be secondary to pathology at any level of the brain-gut axis as well as systemic disease. The clinical features of CIPO are pleomorphic and largely depend on the site and extent of the segment of the GI tract involved. The diagnostic approach includes the need for investigations to exclude mechanical GI obstruction, screening for causes of secondary CIPO and the identification of the disease phenotype as well as the prompt recognition and treatment of complications such as malnutrition and small intestinal bacterial overgrowth. In managing this disorder, a holistic, multidisciplinary approach is needed with judicious use of pharmacotherapeutic agents. While currently there are no specific therapeutic modalities for CIPO, treatment is largely directed at maintaining adequate nutrition and electrolyte balance and enhancing coordinated GI motility. Surgery should be avoided unless advisable for carefully selected patients and may include stoma formation. This narrative review provides a concise overview of the literature on this rare, severe and complex disorder, and highlights the need and areas for further research to improve both diagnostics and therapeutics.

Paediatric Intestinal Pseudo-obstruction: Evidence and Consensus-based Recommendations From an ESPGHAN-Led Expert Group

OBJECTIVES

Chronic intestinal pseudo-obstructive (CIPO) conditions are considered the most severe disorders of gut motility. They continue to present significant challenges in clinical care despite considerable recent progress in our understanding of pathophysiology, resulting in unacceptable levels of morbidity and mortality. Major contributors to the disappointing lack of progress in paediatric CIPO include a dearth of clarity and uniformity across all aspects of clinical care from definition and diagnosis to management. In order to assist medical care providers in identifying, evaluating, and managing children with CIPO, experts in this condition within the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition as well as selected external experts, were charged with the task of developing a uniform document of evidence- and consensus-based recommendations.

METHODS

Ten clinically relevant questions addressing terminology, diagnostic, therapeutic, and prognostic topics were formulated. A systematic literature search was performed from inception to June 2017 using a number of established electronic databases as well as repositories. The approach of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) was applied to evaluate outcome measures for the research questions. Levels of evidence and quality of evidence were assessed using the classification system of the Oxford Centre for Evidence-Based Medicine (diagnosis) and the GRADE system (treatment). Each of the recommendations were discussed, finalized, and voted upon using the nominal voting technique to obtain consensus.

RESULTS

This evidence- and consensus-based position paper provides recommendations specifically for chronic intestinal pseudo-obstruction in infants and children. It proposes these be termed paediatric intestinal pseudo-obstructive (PIPO) disorders to distinguish them from adult onset CIPO. The manuscript provides guidance on the diagnosis, evaluation, and treatment of children with PIPO in an effort to standardise the quality of clinical care and improve short- and long-term outcomes. Key recommendations include the development of specific diagnostic criteria for PIPO, red flags to alert clinicians to the diagnosis and guidance on the use of available investigative modalities. The group advocates early collaboration with expert centres where structured diagnosis and management is guided by a multi-disciplinary team, and include targeted nutritional, medical, and surgical interventions as well as transition to adult services.

CONCLUSIONS

This document is intended to be used in daily practice from the time of first presentation and definitive diagnosis PIPO through to the complex management and treatment interventions such as intestinal transplantation. Significant challenges remain to be addressed through collaborative clinical and research interactions.

Dynamic MRI for bowel motility imaging-how fast and how long?

Objective:

Dynamic imaging of small intestinal motility is an increasingly common research method to examine bowel physiology in health and disease. However, limited data exist to guide imaging protocols with respect to quantitative analysis. The purpose of this study is to define the required temporal resolution and scan duration in dynamic MRI for small bowel motility assessment.

Methods:

Six healthy volunteers underwent motility imaging with MR enterography using breath-hold protocol. A coronal two-dimensional balanced fast field echo sequence was used to acquire dynamic data at a high temporal resolution of 10 frames per second (fps). Motility was quantified by generating a registration-derived motility index for local and global regions of bowel. To evaluate temporal resolution and scan duration, the data were undersampled and the scan length was varied to determine the impact on motility index.

Results:

The mean motility index stabilizes at a temporal resolution of 1 fps (median absolute percentage change 1.4% for global and 1.9% for local regions of interest). The mean motility index appears to stabilize for scan durations of 15 s or more in breath-hold (median absolute % change 2.8% for global and 1.7% for local regions of interest).

Conclusion:

A temporal resolution of at least 1 fps and a scan duration of at least 15 s is necessary in breath-hold scans for consistent motility observations. The majority of small bowel motility studies to date are in line with these requirements.

Advances in knowledge:

This study suggests the minimum temporal resolution and scan duration required in breath-hold scans to obtain robust measurements of small bowel motility from MRI.

Acceleration of small bowel motility after oral administration of dai-kenchu-to (TJ-100) assessed by cine magnetic resonance imaging

Dai-kenchu-to (TJ-100) is an herbal medicine used to shorten the duration of intestinal transit by accelerating intestinal movement. However, intestinal movement in itself has not been evaluated in healthy volunteers using radiography, fluoroscopy, and radioisotopes because of exposure to ionizing radiation. The purpose of this study was to evaluate the effect of TJ-100 on intestinal motility using cinematic magnetic resonance imaging (cine MRI) with a steady-state free precession sequence. Ten healthy male volunteers received 5 g of either TJ-100 or lactose without disclosure of the identity of the substance. Each volunteer underwent two MRI examinations after taking the substances (TJ-100 and lactose) on separate days. They drank 1200 mL of tap water and underwent cine MRI after 10 min. A steady-state free precession sequence was used for imaging, which was performed thrice at 0, 10, 20, 30, 40, and 50 min. The bowel contraction frequency and distention score were assessed. Wilcoxon signed-rank test was used, and differences were considered significant at a P-value <0.05. The bowel contraction frequency tended to be greater in the TJ-100 group and was significantly different in the ileum at 20 (TJ-100, 8.95 ± 2.88; lactose, 4.80 ± 2.92; P < 0.05) and 50 min (TJ-100, 9.45 ± 4.49; lactose, 4.45 ± 2.65; P < 0.05) between the groups. No significant differences were observed in the bowel distention scores. Cine MRI demonstrated that TJ-100 activated intestinal motility without dependence on ileum distention.

Evaluation of gastrointestinal motility with MRI: Advances, challenges and opportunities

Dynamic magnetic resonance imaging (MRI) of gastrointestinal motility has developed rapidly over the past few years. The non-invasive and non-ionizing character of MRI is an important advantage together with the fact that it is fast and can visualize the entire gastrointestinal tract. Advances in imaging and quantification techniques have facilitated assessment of gastric, small intestinal, and colonic motility in a clinical setting. Automated quantitative motility assessment using dynamic MRI meets the need for non-invasive techniques. Recently, studies have begun to examine this technique in patients, including those with IBD, pseudo-obstruction and functional bowel disorders. Remaining challenges for clinical implementation are processing the large amount of data, standardization and validation of the numerous MRI metrics and subsequently assessment of the potential role of dynamic MRI. This review examines the methods, advances, and remaining challenges of evaluation of gastrointestinal motility with MRI. It accompanies an article by Khalaf et al. in this journal that describes a new protocol for assessment of pan-intestinal motility in fasted and fed state in a single MRI session.

Efficacy of percutaneous endoscopic gastro-jejunostomy (PEG-J) decompression therapy for patients with chronic intestinal pseudo-obstruction (CIPO)

BACKGROUNDS

Chronic intestinal pseudo-obstruction (CIPO) is an intractable rare digestive disease manifesting persistent small bowel distension without any mechanical cause. Intestinal decompression is a key treatment, but conventional method including a trans-nasal small intestinal tube is invasive and painful. Therefore, a less invasive and tolerable new decompression method is urgently desired. We conducted a pilot study and assessed the efficacy and safety of percutaneous endoscopic gastro-jejunostomy (PEG-J) decompression therapy in CIPO patients.

METHODS

Seven definitive CIPO patients (2 males and 5 females) were enrolled. All patients received PEG-J decompression therapy. The number of days with any abdominal symptoms in a month (NODASIM), body mass index (BMI), serum albumin level (Alb), and small intestinal volume before and after PEG-J were compared in all patients.

RESULTS

Percutaneous endoscopic gastro-jejunostomy was well tolerated and oral intake improved in all patients. NODASIM has significantly decreased (24.3 vs 9.3 days/months) and BMI/Alb have significantly increased (14.9 vs 17.2 kg/m² and 2.6 vs 3.8 g/dL, respectively), whereas total volume of the small intestine has not significantly reduced (4.05 vs 2.59 L, P=.18). Reflux esophagitis and chemical dermatitis were observed in one case but was successfully treated conservatively.

CONCLUSIONS & INFERENCES

Percutaneous endoscopic gastro-jejunostomy decompression therapy can contribute greatly to improvement of abdominal symptoms and nutritional status in CIPO patients. Although sufficient attention should be paid to acid reflux symptoms, PEG-J has the potential to be a non-invasive novel decompression therapy for CIPO available at home. However, accumulation of more CIPO patients and long-term observation are needed (UMIN000017574).

Magnetic resonance evaluation for small bowel strictures in Crohn's disease: comparison with balloon enteroscopy

BACKGROUND

Magnetic resonance (MR) imaging is the recommended technique for detection of small bowel lesions in Crohn's disease. We aimed to evaluate the impact of stricture findings obtained by MR imaging on patient outcomes using balloon-assisted enteroscopy (BAE) as a reference.

METHODS

Two hundred Crohn's disease patients undergoing both MR enterocolonography and BAE were prospectively followed up for at least 1 year. The presence of strictures detected by MR enterocolonography was compared with endoscopic findings. Moreover, the relationship between MR findings and surgery was evaluated.

RESULTS

The accuracy of MR imaging for detection of small bowel strictures was defined by a sensitivity of 60.6% and a specificity of 93.4%. Major strictures (diameter less than 10 mm or with internal fistula), long strictures (length 10 mm or greater), and prestenotic dilatation were predictors of stricture detection by MR imaging (P = 0.001, 0.017, and 0.002 respectively). Surgery was performed in 31.6% of patients (18 of 57) in the MR-positive-BAE-positive stricture group and in 10.8% of patients (4 of 37) in the MR-negative-BAE-positive stricture group. Multiple regression analysis showed MR-positive-BAE-positive strictures were an independent risk factor for surgery (P = 0.002 at 6 months and P < 0.001 at 1 year). The surgery-free rate in the MR-negative-BAE-positive stricture group was significantly lower than that in nonstricture group at 1 year (P = 0.001).

CONCLUSIONS

The specificity of MR imaging for detection of small bowel strictures was clinically sufficient, and the MR procedure could detect critical strictures, which was a predictive factor for surgery. But MR-negative-BAE-positive strictures were also associated with an increased risk compared with no strictures after 1 year of follow-up.

Small Bowel Motility

PURPOSE OF REVIEW

Small bowel motility disorders constitute a relatively small but important segment of clinical gastroenterology. Presenting features encompass a broad range of symptom manifestations and severity: from chronic functional-type complaints to life-threatening nutritional impairment. Diagnostic assessment of patients with suspected intestinal motility disorders is often hampered by the complexity of measuring intestinal contractile activity in humans. In this review, we describe and critically comment the main current and forthcoming methodologies.

RECENT FINDINGS

Beyond conventional small bowel manometry, radiological methods, and intestinal transit tests that have been available for several decades, now we focus on novel methodologies such as high-resolution manometry, magnetic resonance methodology, and endoluminal capsule image analysis. Gradual introduction of new approaches to diagnostic investigation of patients with suspected intestinal motility disorders should facilitate a less invasive and more accurate characterization of disturbed motor function. Enhanced understanding of the pathophysiological basis of clinical conditions should allow better application of therapeutic approaches that are also highlighted in this review.

Clinical importance of cine-MRI assessment of small bowel motility in patients with chronic intestinal pseudo-obstruction: a retrospective study of 33 patients

BACKGROUND

Although chronic intestinal pseudo-obstruction (CIPO) is a rare and extremely severe functional digestive disorder, its clinical course and severity show various patterns. We assessed small bowel peristalsis in CIPO patients using cine-MRI (video-motion MRI) and their clinical characteristics to evaluate the clinical importance of performing cine-MRI in patients with this intractable disease.

METHODS

The medical records of 131 patients referred to our institution with a suspected diagnosis of CIPO between 2010 and 2015 were retrospectively evaluated. Thirty-three patients (22 female/11 male; age range 16-79 years) who met the criteria for CIPO and underwent cine-MRI were enrolled. Mean luminal diameter (MLD), contraction ratio (CR), and contraction cycle (CC) were determined and compared with these parameters in healthy volunteers. Clinical outcomes in patients with CIPO were also evaluated.

RESULTS

The median follow-up time was 25.2 months (range, 1-65 months). Of the 33 patients with CIPO, 23 (70 %) showed apparently disturbed small intestinal peristalsis, whereas 10 (30 %) did not. The percentage of patients requiring intravenous alimentation was significantly higher (p = 0.03), and the mean serum albumin level was significantly lower (p = 0.04), in patients with than without impaired small intestinal peristalsis. Although both cine-MRI and CT findings in the latter ten cases were within the normal range, MLD and CR differed significantly from healthy volunteers.

CONCLUSIONS

Cine-MRI is useful in predicting severe clinical features in patients with CIPO, and in detecting slightly impaired small contractility that cannot be detected on CT.

Chronic intestinal pseudo-obstruction in children and adults: diagnosis and therapeutic options

BACKGROUND

Chronic intestinal pseudo-obstruction (CIPO) represents the most severe form of gastrointestinal dysmotility with debilitating and potentially lethal consequences. Symptoms can be non-specific, and result in this condition being diagnosed incorrectly or too late with consequences for morbidity and even mortality.

PURPOSE

The present article aims to provide pediatric and adult gastroenterologists with an up to date review about clinical features, diagnosis and therapeutic options for CIPO. Although pediatric and adult CIPO share many clinical aspects distinctive features can be identified. There is no single diagnostic test or pathognomonic finding of CIPO, thus a stepwise approach including radiology, endoscopy, laboratory, manometry, and histopathology should be considered in the diagnostic work-up. Treatment of patients with CIPO is challenging and requires a multidisciplinary effort with participation of appropriately experienced gastroenterologists, pathologists, dieticians, surgeons, psychologists, and other subspecialists based on the presence of comorbidities. Current treatment options invariably involve surgery and specialized nutritional support, especially in children. Medical therapies are mainly aimed to avoid complications such as sepsis or intestinal bacterial overgrowth and, where possible, restore intestinal propulsion. More efficacious therapeutic options are eagerly awaited for such difficult patients.

Disorders of gastrointestinal hypomotility

Ingestion and digestion of food as well as expulsion of residual material from our gastrointestinal tract requires normal propulsive, i.e. motor, function. Hypomotility refers to inherited or acquired changes that come with decreased contractile forces or slower transit. It not only often causes symptoms but also may compromise nutritional status or lead to other complications. While severe forms, such as pseudo-obstruction or ileus, may have a tremendous functional impact, the less severe forms of hypomotility may well be more relevant, as they contribute to common disorders, such as functional dyspepsia, gastroparesis, chronic constipation, and irritable bowel syndrome (IBS). Clinical testing can identify changes in contractile activity, defined by lower amplitudes or abnormal patterns, and the related effects on transit. However, such biomarkers show a limited correlation with overall symptom severity as experienced by patients. Similarly, targeting hypomotility with pharmacological interventions often alters gut motor function but does not consistently improve symptoms. Novel diagnostic approaches may change this apparent paradox and enable us to obtain more comprehensive information by integrating data on electrical activity, mechanical forces, patterns, wall stiffness, and motions with information of the flow of luminal contents. New drugs with more selective effects or more specific delivery may improve benefits and limit adverse effects. Lastly, the complex regulation of gastrointestinal motility involves the brain-gut axis as a reciprocal pathway for afferent and efferent signaling. Considering the role of visceral input in emotion and the effects of emotion on visceral activity, understanding and managing hypomotility disorders requires an integrative approach based on the mind-body continuum or biopsychosocial model of diseases.

Comparative quantitative assessment of global small bowel motility using magnetic resonance imaging in chronic intestinal pseudo-obstruction and healthy controls

BACKGROUND

Chronic intestinal pseudo-obstruction (CIPO) is characterized by dilatation of the bowel lumen and abnormal motility. In this study, we aimed to quantify small bowel dysmotility in CIPO using a validated pan-intestinal motility assessment technique based on motion capture magnetic resonance imaging (MRI) compared to normal controls. In addition, we explored if motility responses of CIPO patients to neostigmine challenge differed from healthy volunteers.

METHODS

Twenty healthy volunteers (mean age 28, range 22-48) and 11 CIPO patients (mean age 47, range 19-90) underwent MRI enterography to capture global small bowel motility. Eleven controls and seven CIPO patients further underwent a randomized placebo-controlled crossover study of either intravenous neostigmine (0.5 mg) or saline with motility MRI repeated at a mean of 3 weeks. Motility was quantified in regions of interest placed to encompass the whole small bowel volume using a validated, postprocessing technique to give a global motility index in arbitrary units (AU). Baseline and stimulated motility was compared using Wilcoxon rank-sum paired T-tests.

KEY RESULTS

Baseline global small bowel motility was significantly lower in CIPO patients compared to controls (mean 0.25 AU vs 0.35 AU, p < 0.001). Motility in both groups increased significantly after neostigmine (0.06 AU increase, p = 0.016 in CIPO and 0.06 AU increase, p = 0.002 in controls). Three patients with scleroderma had a reduced response to neostigmine.

CONCLUSIONS & INFERENCES

Global small bowel motility in CIPO patients is significantly lower than controls and response to the pro-kinetic agent neostigmine may differ according to disease phenotype. Software-quantified bowel motility using cine MRI has potential as a future tool to investigate enteric dysmotility.

Avicenna's View on the Etiologies of Intestinal Obstruction

Context:

Bowel obstruction is one of the most common causes of acute abdomen. Because of heterogeneity of patients’ population and variety of causes, therapeutic strategies are not standardized, so treatment of intestinal obstruction is a surgical challenge in many cases. A traditional medicine approach could help detect some issues that were ignored by modern medicine. One of the major schools of medicine, with a history of several thousand years, is Iranian traditional medicine. In this regard, Avicenna, who lived in the medieval period, has had a great influence on the medical knowledge of the world by writing an encyclopedia of medicine entitled “Qanun of Medicine.”

Evidence Acquisition:

The aim of this study was to investigate Avicenna’s views on the causes of intestinal obstruction and comparing them to modern medicine views. This is a review study on an Iranian traditional textbook of medicine by Avicenna, entitled “Qanun of Medicine” (in short “Qanun”). We used Qanun in its original language (Arabic) along with its Persian translation. It consists of 5 books. Part 16 of the third book talks about intestinal anatomy and introduces some intestinal diseases such as “qoolinj” and “ilavos.” Intestinal obstruction can be a kind of “qoolinj” or “ilavos” disease. All intestinal obstruction etiologies in Qanun are searched in international and Iranian databases (Scopus, ISI, SID, and Iranmedex) and similar causes in modern medicine will be discussed in this article.

Results:

According to Qanun, 16 causes are involved in intestinal etiologies of bowel obstruction such as “reeh,” mucoid phlegm, abdominal hot and dry distemperament, decreased bile secretion, job, and so on while modern medicine considers some of them, for instance, volvulus, intestinal herniation, worm, intestinal pseudo-obstruction, and opiate.

Conclusions:

Attention to the similar causes of intestinal obstruction in modern medicine and traditional medicine is the starting point for investigation of noninvasive diagnostic and therapeutic methods that have been mentioned in Qanun. In addition, etiologies which are missed in modern medicine can open new doors to the researchers and gastroenterologists for the study, diagnosis, and prevention of the disease.

Magnetic resonance imaging biomarkers of gastrointestinal motor function and fluid distribution

Magnetic resonance imaging (MRI) is a well established technique that has revolutionized diagnostic radiology. Until recently, the impact that MRI has had in the assessment of gastrointestinal motor function and bowel fluid distribution in health and in disease has been more limited, despite the novel insights that MRI can provide along the entire gastrointestinal tract. MRI biomarkers include intestinal motility indices, small bowel water content and whole gut transit time. The present review discusses new developments and applications of MRI in the upper gastrointestinal tract, the small bowel and the colon reported in the literature in the last 5 years.

Current clinical features in diagnosis and treatment for immaturity of ganglia in Japan: analysis from 10-year nationwide survey

BACKGROUND

To identify the current clinical features in diagnosis and treatment for immaturity of ganglia (IG) in Japan, we retrospectively analyzed data for patients with IG from the nationwide surveys in Japan. This survey was performed by Japanese Study Group of allied disorders of Hirschsprung's disease (ADHD).

METHODS

In primary research, data on totally 355 cases of ADHD were collected for 10 years (2001-2010). Fifteen patients were IG. All IG patients were confirmed by pathological examination. In secondary research, detail questionnaires were sent and collected.

RESULTS

Male/female ratio was 9/6 and mean birth weight was 2474 g. All cases (100 %) were onset in neonatal period. Primary symptoms were abdominal distention (86.7 %), vomiting (53.3 %), and late egestion of meconium (26.7 %). An abnormal distention of intestine was recognized in 86.7 % on X-ray, and microcolon was recognized in 58.3 % on contrast enema. Caliber change was recognized in 58.3 % on laparotomy. An enterostomy was made in 13 patients (86.7 %), and an ileostomy was made in 69.2 %. Pathological diagnosis was performed in 100 %. Enterostomy was closed in 100 %.

CONCLUSIONS

Totally, 15 definitive cases of IG in 10 years were collected and analyzed. All cases were onset in the neonatal period and almost all underwent enterostomy, but no mortalities occurred.

Classification of functional bowel disorders by objective physiological criteria based on endoluminal image analysis

We have previously developed an original method to evaluate small bowel motor function based on computer vision analysis of endoluminal images obtained by capsule endoscopy. Our aim was to demonstrate intestinal motor abnormalities in patients with functional bowel disorders by endoluminal vision analysis. Patients with functional bowel disorders (n = 205) and healthy subjects (n = 136) ingested the endoscopic capsule (Pillcam-SB2, Given-Imaging) after overnight fast and 45 min after gastric exit of the capsule a liquid meal (300 ml, 1 kcal/ml) was administered. Endoluminal image analysis was performed by computer vision and machine learning techniques to define the normal range and to identify clusters of abnormal function. After training the algorithm, we used 196 patients and 48 healthy subjects, completely naive, as test set. In the test set, 51 patients (26%) were detected outside the normal range (P < 0.001 vs. 3 healthy subjects) and clustered into hypo- and hyperdynamic subgroups compared with healthy subjects. Patients with hypodynamic behavior (n = 38) exhibited less luminal closure sequences (41 ± 2% of the recording time vs. 61 ± 2%; P < 0.001) and more static sequences (38 ± 3 vs. 20 ± 2%; P < 0.001); in contrast, patients with hyperdynamic behavior (n = 13) had an increased proportion of luminal closure sequences (73 ± 4 vs. 61 ± 2%; P = 0.029) and more high-motion sequences (3 ± 1 vs. 0.5 ± 0.1%; P < 0.001). Applying an original methodology, we have developed a novel classification of functional gut disorders based on objective, physiological criteria of small bowel function.

Advancement in the clinical management of intestinal pseudo-obstruction

Intestinal pseudo-obstruction is more commonly known in its chronic form (CIPO), a cluster of rare diseases characterized by gastrointestinal muscle and nerve impairment, so severe to result in a markedly compromised peristalsis mimicking an intestinal occlusion. The management of CIPO requires the cooperation of a group of specialists: the disease has to be confirmed by a number of tests to avoid mistakes in the differential diagnosis. The treatment should be aimed at relieving symptoms arising from gut dysmotility (ideally using prokinetic agents), controlling abdominal pain (possibly with non-opioid antinociceptive drugs) and optimizing nutritional support. Furthermore, a thorough diagnostic work-up is mandatory to avoid unnecessary (potentially harmful) surgery and to select patients with clear indication to intestinal or multivisceral transplantation.

Quantitative in vivo analysis of small bowel motility using MRI examinations in mice--proof of concept study

Small bowel motility analyses using magnetic resonance imaging (MRI) could reduce current invasive techniques in animal studies and comply with the 'three Rs' rule for human animal experimentation. Thus we investigated the feasibility of in vivo small bowel motility analyses in mice using dynamic MRI acquisitions. All experimental procedures were approved by the institutional animal care committee. Six C57BL/6 mice underwent MRI without additional preparation after isoflurane anaesthetization in the prone position on a 4.7 T small animal imager equipped with a linear polarized hydrogen birdcage whole-body mouse coil. Motility was assessed using a true fast imaging in a steady precession sequence in the coronal orientation (acquisition time per slice 512 ms, in-plane resolution 234 × 234 µm, matrix size 128 × 128, slice thickness 1 mm) over 30 s corresponding to 60 acquisitions. Motility was manually assessed measuring the small bowel diameter change over time. The resulting motility curves were analysed for the following parameters: contraction frequency per minute (cpm), maximal contraction amplitude (maximum to minimum [mm]), luminal diameter (mm) and luminal occlusion rate. Small bowel motility quantification was found to be possible in all animals with a mean small bowel contraction frequency of 10.67 cpm (SD ± 3.84), a mean amplitude of the contractions of 1.33 mm (SD ± 0.43) and a mean luminal diameter of 1.37 mm (SD ± 0.42). The mean luminal occlusion rate was 1.044 (SD ± 0.45%/100). The mean duration needed for a single motility assessment was 185 s (SD ± 54.02). Thus our study demonstrated the feasibility of an easy and time-sparing functional assessment for in vivo small bowel motility analyses in mice. This could improve the development of small animal models of intestinal diseases and provide a method similar to clinical MR examinations that is in concordance with the 'three Rs' for humane animal experimentation.

Dysmotility disorders: a nutritional approach

PURPOSE OF REVIEW

Chronic intestinal pseudo-obstruction (CIPO) results in markedly compromised peristalsis mimicking an intestinal occlusion. The main goals of CIPO management are to improve intestinal propulsion and to maintain adequate nutrition status. The review describes the global management of CIPO including methods of diagnosis and nutritional, pharmacological and surgical therapies.

RECENT FINDINGS

The principles of CIPO management are to perform a physiological assessment of the gastrointestinal tract involved, to improve symptoms and to prevent malnutrition. We shall discuss the place of physiological motility tests such as intestinal manometry and the cine-magnetic resonance imaging to facilitate diagnosis. Home parenteral nutrition (HPN) is a frequently used therapy with a high dependence level. However, recent data are consistent with a good long-term prognosis. Currently, CIPO becomes a significant cause of chronic intestinal failure. We discuss the outcomes of HPN and surgery.

SUMMARY

CIPO is a rare and complex disease. Small bowel manometry remains a gold standard for diagnosis, but new imaging tools appear promising. The management of CIPO requires the cooperation of specialists involved in the intestinal failure field. The better knowledge of CIPO prognosis should encourage clinicians to propose intestinal transplantation in selected cases.

The challenge of segmental small bowel motility quantitation using MR enterography

OBJECTIVE

Analysis of "cine" MRI using segmental regions of interest (ROIs) has become increasingly popular for investigating bowel motility; however, variation in motility in healthy subjects both within and between scans remains poorly described.

METHODS

20 healthy individuals (mean age, 28 years; 14, males) underwent MR enterography to acquire dynamic motility scans in both breath hold (BH) and free breathing (FB) on 2 occasions. Motility data were quantitatively assessed by placing four ROIs per subject in different small bowel segments and applying two measures: (1) contractions per minute (CPM) and (2) Jacobian standard deviation (SD) motility score. Within-scan (between segment) variation was assessed using intraclass correlation (ICC), and repeatability was assessed using Bland-Altman limits of agreement (BA LoA).

RESULTS

Within-scan segmental variation: BH CPM and Jacobian SD metrics between the four segments demonstrated ICC R = 0.06, p = 0.100 and R = 0.20, p = 0.027 and in FB, the CPM and Jacobian SD metrics demonstrated ICC R = -0.26, p = 0.050 and R = 0.19, p = 0.030. Repeatability: BH CPM for matched segments ranged between 0 and 14 contractions with BA LoA of ±8.36 and Jacobian SD ranged between 0.09 and 0.51 with LoA of ±0.33. In FB data, CPM ranged between 0 and 10 contractions with BA LoA of ±7.25 and Jacobian SD ranged between 0.16 and 0.63 with LoA = ±0.28.

CONCLUSION

The MRI-quantified small bowel motility in normal subjects demonstrates wide intersegmental variation and relatively poor repeatability over time.

ADVANCES IN KNOWLEDGE

This article presents baseline values for healthy individuals of within- and between-scan motility that are essential for understanding how this process changes in disease.

Small-bowel dislocation during long-term MRI observation - insights in intestinal physiology

Magnetic resonance imaging (MRI) of the abdomen is a widely established imaging modality in the diagnostic workup of patients suffering from abdominal disorders. Small-bowel motility analyses using MRI have recently been introduced to provide functional information about the intestine not provided by morphological analyses. This is of clinical importance as motility disorders correlate with inflammation. Yet motility analyses mainly rely on a series of acquisitions in coronal orientation. Temporal displacement of small-bowel loops out of the coronal slice could falsify qualitative and quantitative motility analyses. Thus, our study quantified three-dimensional (3D) dislocation of small-bowel loops during abdominal MRI examinations with the patient lying in prone position to investigate its influence on motility analyses. Our study revealed segmental small-bowel displacement during MRI examinations in prone position to predominantly occur in craniocaudal orientation and in a smaller extent in lateral and ventrodorsal orientation. However, the displacement amplitudes are rather small and might not significantly influence small-bowel motility analyses in 2D coronal plane in general.