Review
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. May 28, 2017; 23(20): 3607-3614
Published online May 28, 2017. doi: 10.3748/wjg.v23.i20.3607
Brain changes detected by functional magnetic resonance imaging and spectroscopy in patients with Crohn's disease
Kun Lv, Yi-Hong Fan, Li Xu, Mao-Sheng Xu
Kun Lv, The First Clinical Medical College of Zhejiang Chinese Medical University, Hangzhou 310053, Zhejiang Province, China
Kun Lv, Mao-sheng Xu, Department of Radiology, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou 310006, Zhejiang Province, China
Yi-Hong Fan, Department of Gastroenterology, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou 310006, Zhejiang Province, China
Li Xu, Department of Coloproctology, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou 310006, Zhejiang Province, China
Author contributions: All authors contributed to this paper; Fan YH and Xu MS designed the outline for the review; Lv K wrote the review; Xu L offered assistance for grammatical revision of the paper; Lv K and Xu MS revised and edited the final version.
Supported by the National Natural Science Foundation of China, No. 81473506; the Natural Science Foundation of Zhejiang Province, No. LY17H290009; and the Ministry of construction, Zhejiang Province, No. WKJ-ZJ-1531.
Conflict-of-interest statement: No potential conflicts of interest exist.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (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/
Correspondence to: Mao-sheng Xu, MD, PhD, Chief, Department of Radiology, The First Affiliated Hospital of Zhejiang Chinese Medical University, 54 Youdian Road, Shangcheng District, Hangzhou 310006, Zhejiang Province, China. xums166@126.com
Telephone: +86-571-87070272 Fax: +86-571-87077785
Received: January 5, 2017
Peer-review started: January 6, 2017
First decision: January 19, 2017
Revised: February 6, 2017
Accepted: March 30, 2017
Article in press: March 30, 2017
Published online: May 28, 2017
Abstract

Crohn’s disease (CD) is a chronic, non-specific granulomatous inflammatory disorder that commonly affects the small intestine and is a phenotype of inflammatory bowel disease (IBD). CD is prone to relapse, and its incidence displays a persistent increase in developing countries. However, the pathogenesis of CD is poorly understood, with some studies emphasizing the link between CD and the intestinal microbiota. Specifically, studies point to the brain-gut-enteric microbiota axis as a key player in the occurrence and development of CD. Furthermore, investigations have shown white-matter lesions and neurologic deficits in patients with IBD. Based on these findings, brain activity changes in CD patients have been detected by blood oxygenation level dependent functional magnetic resonance imaging (BOLD-fMRI). BOLD-fMRI functions by detecting a local increase in relative blood oxygenation that results from neurotransmitter activity and thus reflects local neuronal firing rates. Therefore, biochemical concentrations of neurotransmitters or metabolites may change in corresponding brain regions of CD patients. To further study this phenomenon, brain changes of CD patients can be detected non-invasively, effectively and accurately by BOLD-fMRI combined with magnetic resonance spectroscopy (MRS). This approach can further shed light on the mechanisms of the occurrence and development of neurological CD. Overall, this paper reviews the current status and prospects on fMRI and MRS for evaluation of patients with CD based on the brain-gut-enteric microbiota axis.

Keywords: Brain-gut-enteric microbiota axis, Crohn’s disease, Functional magnetic resonance spectroscopy, Functional magnetic resonance imaging, Gut microbiota, Inflammatory bowel disease, Metabolite, Spectroscopy

Core tip: The occurrence and development of Crohn’s disease (CD) have strong links to the brain-gut-enteric microbiota axis and are associated with psychological factors such as stress, anxiety and depression. In patients with inflammatory bowel disease, studies have revealed white-matter lesions and neurologic disorders. Brain activity and biochemical changes in brain regions can be detected accurately by blood oxygenation level dependent functional magnetic resonance imaging combined with magnetic resonance spectroscopy in patients with CD. This approach can further shed light on the mechanism of occurrence of neurologic CD.