Page 10 - JCBP-2-1

Journal of Clinical and
Basic Psychosomatics MRI and functional constipation

facets of life, these shifts have led to corresponding Therefore, brain imaging is gaining traction as a
adjustments in nutrient intake and digestion, contributing method for exploring brain abnormalities in patients
to a heightened incidence of functional gastrointestinal with FGID . A growing body of research has employed
[14]
disorder (FGID). Among the prevalent FGIDs, functional magnetic resonance imaging (MRI), a non-destructive,
constipation (FC) exhibits an annual increase [1,2] . FC is non-invasive, high spatial resolution imaging technique, to
defined as constipation lacking an organic etiology and is characterize both functional and structural changes in the
[15]
diagnosed based on the Rome criteria. This condition is brain . One widely studied mode, functional MRI (fMRI),
characterized by reduced stool frequency, the presence of is employed to deduce local neuronal activity by measuring
hard and/or large stools, painful defecation, the sensation changes in blood-oxygen-level dependent (BOLD) signals
of incomplete evacuation, and often accompanied by resulting from alterations in the paramagnetic properties
abdominal distension and pain [3,4] . Global surveys of hemoglobin [16,17] . Analysis of the BOLD signal through
utilizing the Rome IV criteria indicate a 10.1% incidence fMRI provides valuable insights into the function of different
of FC, with a higher prevalence among female patients brain regions and their involvement in various cognitive
than males (2.1:1) . Additionally, studies have indicated processes. Resting-state fMRI (RS-fMRI) is employed to
[5]
that patients experiencing long-term FC are prone to evaluate baseline brain activity levels and intrinsic functional
anxiety and depressive symptoms. The incidence of FC connectivity [18,19] . Structural MRI (sMRI) is utilized to gather
is higher in patients with mental disorder than healthy data about gray-matter (GMV) and white-matter volumes
[6]
[21]
[20]
control (HC) . Patients with FC frequently expressed (WMV) , as well as cortical morphometry . Diffusion
challenges in finding relief from persistent constipation tensor imaging (DTI) provides information about the
symptoms . The repercussions of FC extend beyond microstructure and connectivity of white matter (WM) by
[7]
individual experiences, placing a substantial burden on measuring the directional characteristics of water molecule
both families and society. diffusion within tissues . A plethora of neuroimaging
[22]
[23]
The bidirectional brain-gut interaction plays a studies have been conducted in patients with IBS . These
crucial role in gastrointestinal function and health. The studies have successfully pinpointed dysfunctions within
brain exerts influence on the gastrointestinal tract by brain regions responsible for regulating both somatic and
[18,24]
sending commands that impact motility, secretion, and visceral pain . Additionally, sMRI studies in patients
[25]
sensation. Simultaneously, the gastrointestinal tract with FGID have shown changes in cortical morphometry .
communicates with the brain, conveying information The existing literature has systematically reviewed the
about its status and function . This interaction involves mechanisms of brain-gut interactions and abnormal internal
[8]
[26]
various pathways, including neural connections, brain activity in patients with IBS . However, as a typical
neurotransmitters, hormones, the immune system, FGID, a systematic review discussing the pathological
and the gut microbiota. The gut microbiota not only mechanism of FC in terms of abnormal brain activity has
directly interacts with the gastrointestinal tract but also not yet been published.
communicates with the immune system and the nervous In this review, we synthesized findings from MRI-based
system through various signaling systems. Its homeostasis studies that delve into the brain anomalies observed in
is the premise for the normal functioning of the brain- patients with FC, along with its underlying pathological
gut axis [9,10] . Studies have confirmed the sensitivity of mechanisms. All subjects in these studies met the
the gut microbiota to mood and environmental stimuli diagnostic criteria for Rome Ⅳ pairs of FC and excluded
(stress). Changes in its metabolite levels have been related patients with psychiatric disorders or those who may have
to neurological diseases such as anorexia nervosa, long- taken medications affecting the central nervous system.
term anxiety, and depression . Disordered brain-gut Studies focusing on psychological factors utilized anxiety/
[11]
interactions are believed to be the underlying cause of depressive status rating (self-rating anxiety scale, Zung’s
symptom generation in several FGIDs. Previous studies self-rating depression scale [SDS], state anxiety inventory,
have confirmed that abnormalities in autonomic nervous and Trait Anxiety Inventory [TAI]) to accurately identify
system regulation and the immune system contribute FC subtypes as patients with anxiety/depressive disorders
to irritable bowel syndrome (IBS), a prevalent FGID . (FCAD) and those without anxiety/depressive disorders
[12]
Additionally, patients with FGIDs exhibit disordered gut (FCNAD). We commenced by examining the effects of
microbiota composition and function . These findings FC on both brain functional and structural abnormalities.
[13]
unveil the close association of FGIDs with psychological Pertaining to brain dysfunction, we explored alterations in
factors. Nevertheless, the direct impact of FGIDs and regional activity and the integrity of functional connections.
psychological factors on brain functions and structures Concerning brain structure, our focus was on alterations in
remains unclear. cortical morphology, as well as GMV/WMV changes. We

Volume 2 Issue 1 (2024) 2 https://doi.org/10.36922/jcbp.1463