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

Effects of opium tincture on gastrointestinal function and motility in healthy volunteers: A magnetic resonance imaging study

BACKGROUND

Opioids inhibit motility and secretion of the gut and have been used for antidiarrheal treatment for centuries. However, the underlying mechanisms of opium tincture are not evident.

AIM

To investigate the effects of opium tincture on gastrointestinal motility, intestinal volumes, and water content of different gut segments assessed by magnetic resonance imaging (MRI).

METHODS

Twenty healthy volunteers were included in a randomized, placebo-controlled, crossover study of 9 days of treatment with 30 drops of opium tincture per day. MRI was performed on day 1 (before treatment) and day 9 (during treatment). Measurements included assessments of gastric volume, gastric emptying, gastric motility, small bowel volume, small bowel water content, small bowel motility, colon volume, colon water content, and whole gut transit.

KEY RESULTS

Opium tincture delayed gastric emptying by a mean difference of 5.6 min [95% CI: 1.8-9.4], p = 0.004, and increased postprandial gastric meal volume (17-21%, p = 0.02). Small bowel endpoints did not change. Opium tincture delayed whole gut transit time (p = 0.027) and increased ascending colon volume by 59 mL [95% CI: 15-103], p = 0.004, and transverse colon volume by 48 mL [95% CI: 4-92], p = 0.027. T1-relaxation time of the descending colon chyme was decreased during opium treatment, indicating dryer feces (difference: -173 ms [95% CI: -336 -11], p = 0.03).

CONCLUSION AND INFERENCES

Opium tincture induced changes in the stomach and colon in healthy volunteers. An improved understanding of how opioids affect gut functions may lead to a better understanding and optimized management of diarrhea.

The Challenge of Small Intestine Length Measurement: A Systematic Review of Imaging Techniques

BACKGROUND

Short bowel syndrome is the most common cause of intestinal failure, with morbidity and mortality linked to remanent small intestine length. There is no current standard for noninvasive bowel length measurement.

MATERIALS AND METHODS

The literature was systematically searched for articles describing measurements of small intestine length from radiographic studies. Inclusion required reporting intestinal length as an outcome and use of diagnostic imaging for length assessment compared to a ground truth. Two reviewers independently screened studies for inclusion, extracted data, and assessed study quality.

RESULTS

Eleven studies met the inclusion criteria and reported small intestinal length measurement using four imaging modalities: barium follow-through, ultrasound, computed tomography, and magnetic resonance. Five barium follow-through studies reported variable correlations with intraoperative measurements (r = 0.43-0.93); most (3/5) reported underestimation of length. US studies (n = 2) did not correlate with ground truths. Two computed tomography studies reported moderate-to-strong correlations with pathologic (r = 0.76) and intraoperative measurements (r = 0.99). Five studies of magnetic resonance showed moderate-to-strong correlations with intraoperative or postmortem measurements (r = 0.70-0.90). Vascular imaging software was used in two studies, and a segmentation algorithm was used for measurements in one.

CONCLUSIONS

Noninvasive measurement of small intestine length is challenging. Three-dimensional imaging modalities reduce the risk of length underestimation, which is common with two-dimensional techniques. However, they also require longer times to perform length measurements. Automated segmentation has been trialed for magnetic resonance enterography, but this method does not translate directly to standard diagnostic imaging. While three-dimensional images are most accurate for length measurement, they are limited in their ability to measure intestinal dysmotility, which is an important functional measure in patients with intestinal failure. Future work should validate automated segmentation and measurement software using standard diagnostic imaging protocols.

Hirschsprung disease and Paediatric Intestinal Pseudo-obstruction

Hirschsprung disease (HSCR) and Paediatric Intestinal Pseudo-obstruction (PIPO) comprise two of the most recognized and severe disorders of gastrointestinal (GI) motility. HSCR is a developmental disorder of the enteric nervous system invariably affecting the large intestine, whereas the majority of PIPO conditions represent congenital disorders of one or more components of the neuromusculature and more diffusely affect the GI tract. Histopathology is deemed the gold standard for the diagnosis of HSCR and, arguably, of PIPO, but, other diagnostic modalities such as manometric and genetic studies have seen recent advances that may increase their utility. Especially for PIPO, management is multidisciplinary and best performed in specialist referral centres. Surgery remains the only viable treatment for HSCR and appears essential to optimize and sustain feeding and viability of intestinal function in PIPO patients. Novel therapies such as neural stem cell transplants show promise for the future.

Mimicking conditions of intestinal Crohn's disease: magnetic resonance enterography findings

Crohn's disease is a chronic inflammatory condition characterized by a transmural involvement of intestinal walls. Its diagnosis comes from a combination of clinical data, imaging findings and, above all, endoscopy with biopsy results, which are mandatory for achieving a definitive diagnosis. Even so, endoscopy information may be unavailable, for instance due to technical impairments or patient intolerance. On the radiological side, Magnetic Resonance Enterography is currently considered the imaging technique of choice for Crohn's disease assessment, either at first diagnosis or follow-up. Nevertheless, the lack of radiation exposure as well as invasiveness has made this imaging approach suitable also for the evaluation of a number of small and large bowel diseases over recent years. However, it is important to remember that Magnetic Resonance Imaging findings are non-specific and that a wide overlap exists among Crohn's disease and other intestinal conditions. The aim of this work was to provide a series of intestinal affections evaluated through Magnetic Resonance Enterography that resemble Crohn's disease and that can be helpful in avoiding misinterpretation, especially when endoscopy data are missing.

Nodular lymphoid hyperplasia of terminal ileum: how to avoid overdiagnosis of Crohn's terminal ileitis in MR enterography?

PURPOSE

To investigate the magnetic resonance enterography (MRE) characteristics of nodular lymphoid hyperplasia (NLH) and Crohn's terminal ileitis (CTI).

METHODS

Of 1552 MREs from November 2011 to July 2018, 61 individuals with biopsy-proven NLH (n = 24) and CTI (n = 37, 27 with active CTI) were selected based on the inclusion criteria. NLH cases were also followed up for median (range) of 40 (21-61) months. Two board-certified radiologists, blind to clinical data and diagnosis, reviewed MRE in consensus. Conventional, morphological, enhancement, and diffusion parameters were assessed. Mann-Whitney, χ², and logistic regression analyses were conducted.

RESULTS

No NLH patient developed inflammatory bowel disease or lymphoproliferative disorders during the follow-up. Serosal surface irregularity (65% vs. 8%), pseudo-diverticula (27% vs. 0), and mesenteric fat involvement (38% vs. 4%) were more frequent in CTI than NLH (p < 0.01), while mucosal nodularity was more prevalent in NLH (71%) than CTI (19%) (p < 0.001). The upstream luminal diameter (15.0 vs. 12.5 mm, p = 0.015) and mural thickness (6.0 vs. 4.0 mm, p < 0.001) of the terminal ileum showed higher values in CTI than NLH.

CONCLUSIONS

Unlike enhancement and diffusion parameters, morphological features (mucosal nodularity, serosal surface irregularity, and mesenteric fat involvement) could distinguish NLH from CTI regardless of CTI activity.

Cause inhabituelle d´une occlusion colique, sténose anale post-radique: à propos d´un cas et revue de la littératurePost-radiation anal stenosis as an unusual cause of colic occlusion: case study and literature review

Résumé

L´occlusion radique est une complication grave de l´entéropathie radique. Elle survient chez les patients sous radiothérapie suivis pour cancer gynécologique ou du rectum. Sa prise en charge nécessite une attention particulière pour améliorer la survie de ces patients. A partir d´un cas ayant été opéré pour cancer du rectum et qui a présenté une occlusion sur sténose serrée post-radique du canal anal et de la partie distale du sigmoïde, nous allons décrire la physiopathologie de cette entité rare et illustrer la valeur de l´imagerie dans la prise en charge de cette pathologie.

English abstract

Post-radiation occlusion is a serious complication of radiation enteropathy. It occurs in patients undergoing radiotherapy for gynecologic or rectal cancer. Accurate management is essential to improve patients' survival. We here report the case of a patient undergoing surgery for rectal cancer. He had post-radiation stricture due to tight stenosis of the anal canal and of the distal end of the sigmoid colon. This study describes the pathophysiology of this rare entity and highlights the role of imaging tests in the management of this disorder.