Observational Study
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Sep 28, 2020; 26(36): 5484-5497
Published online Sep 28, 2020. doi: 10.3748/wjg.v26.i36.5484
Motility index measured by magnetic resonance enterography is associated with sex and mural thickness
Sven Månsson, Olle Ekberg, Bodil Ohlsson
Sven Månsson, Medical Radiation Physics, Department of Translational Medicine, Lund University, Skåne University Hospital Malmö, Malmö 20502, Sweden
Olle Ekberg, Department of Translational Medicine, Diagnostic Radiology, Lund University, Skåne University Hospital, Malmö 20502, Sweden
Bodil Ohlsson, Department of Internal Medicine, Skåne University Hospital, Lund University, Malmö S-205 02, Sweden
Author contributions: Ekberg O, Månsson S and Ohlsson B designed and performed the research study; Ekberg O, Månsson S and Ohlsson B analyzed the data; Ohlsson B wrote the initial draft of the paper; all authors contributed to the intellectual process during the writing and finalization of the manuscript.
Supported by the Development Foundation of Region Skåne, No. REGSKANE-619091; the Foundation of Skåne University Hospital, No. 2017-008; and the Dir Albert Påhlsson’s Foundation, No. 2019.
Institutional review board statement: This study was performed in accordance with the Helsinki Declaration and approved by the Ethics Review Board at Lund University (No 2016/330, date of approval 4 August 2016). All patients and healthy volunteers gave their written informed consent before inclusion.
Conflict-of-interest statement: There are no conflicts of interest for any of the authors.
Data sharing statement: Technical appendix, statistical code, and dataset available from the corresponding author at email adress bodil.ohlsson@med.lu.se.
STROBE statement: The guidelines of the STROBE Statement have been adopted.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Bodil Ohlsson, MD, PhD, Professor, Department of Internal Medicine, Skåne University Hospital, Lund University, Jan Waldenströms Street 15, Malmö S-205 02, Sweden. bodil.ohlsson@med.lu.se
Received: June 12, 2020
Peer-review started: June 12, 2020
First decision: July 25, 2020
Revised: July 27, 2020
Accepted: September 4, 2020
Article in press: September 4, 2020
Published online: September 28, 2020
Processing time: 103 Days and 19 Hours
ARTICLE HIGHLIGHTS
Research background

Symptoms in the gastrointestinal tract are common and nonspecific. Magnetic resonance enterography (MRE) is therefore often used to diagnose or exclude the presence of structural lesions related to inflammatory bowel disease (IBD). If MRE does not show any organic lesions, the patients are suspected to be healthy or are diagnosed as irritable bowel syndrome (IBS). Dysmotility of the small bowel is observed both as a primary disease and secondary to several common diseases such as diabetes and neurological diseases. Dysmotility may cause similar symptoms as IBD, but dysmotility is difficult to diagnose and the condition is often over-looked. In the absence of proper investigation, which are often invasive and not easily available, patients with gastrointestinal dysmotility may be without any treatment.

Research motivation

Studies have described that MRE also can be used to assess motility by calculating motility index (MI), based on displacement mapping. If MRE could be used also to assess gastrointestinal motility, patients with dysmotility could possibly be identified earlier in the disease course, and selected patients could be referred to further examinations. Thus, patients with gastrointestinal dysmotility could be treated appropriately.

Research objectives

The objective of the present study was to evaluate the usefulness and potential of the MI in a large cohort of unselected patients and healthy controls to examine whether the MI could be helpful to identify also altered motility patterns in addition to morphological MRE changes. The main focus was to examine the association between the MI and basal characteristics and gastrointestinal symptoms.

Research methods

All consecutive patients referred for MRE during a 2-year period were asked to participate. Healthy volunteers were included as controls. MRE was prepared and conducted in accordance with clinical routines. All the participants had to complete the visual analog scale for IBS and IBS-symptom severity scale to assess gastrointestinal symptoms and all medical records were scrutinized. Maps of MI were calculated from dynamic MR images. ANOVA was used to evaluate differences in MI between groups, classified as healthy, Crohn’s disease, ulcerative colitis, IBS, other assorted disorders and dysmotility. Logistic and linear regression were applied to the MI values.

Research results

There was a difference in MI between the disease groups in jejunum and terminal ileum (P = 0.021 and P = 0.07), which was explained by a difference between controls and other assorted diseases (P = 0.043 and P = 0.059). The weight was higher in men than in women (OR = 1.056; 95%CI: 1.035-1.081; P < 0.001), and MI of the terminal ileum tended to be lower in men than in women (OR = 0.035; 95%CI: 0.001-1.086; P = 0.056). In men, MI of the terminal ileum was inversely associated with increased mural thickness (P < 0.001). There was a tendency to association between MI and constipation (P = 0.053) and weight (P = 0.081). In women, MI of the jejunum was inversely associated with diarrhea (P = 0.029) and MI of the terminal ileum was associated with constipation (P = 0.039). There was a tendency to inverse association between MI of the terminal ileum and mural thickness (P = 0.063).

Research conclusions

Although MIs differ across diseases, the most important findings of the present study are that a lower MI of the terminal ileum is mainly associated with male sex and an increased mural thickness. Symptoms are weakly associated with the MI.

Research perspectives

Before introduction of this technique in the daily clinical practice, the MI should be less affected by mural thickness, sex and weight or classified by proper criteria for different weights and sexes. Additional techniques probably need to be developed to identify motility patterns by MRE, less influenced by basal characteristics. Furthermore, this method should be compared with other established modalities such as antroduodenal manometry and wireless capsules to evaluate motility.