Imaging findings of irritable bowel syndrome patients, and the diagnostic value of irritable bowel syndrome: A systematic review

Table 1 Basic characteristics and imaging results among patients with irritable bowel syndrome, mean ± SD

Ref.	Country	Study design	Sample size	Age/years	Females, %	Main result
Klinge et al[19], 2022	Denmark	Case-control	20	25-53	76%	Low colonic volume and rapid transit time among IBS patients compared to chronic constipation
Lam et al[20], 2016	United Kingdom	Case-control	48	27-53	91.3%	Higher ascending colon volume in functional constipation compared to IBS patients
Pritchard et al[21], 2014	United Kingdom	Case-control	50	39 ± 13	58.7%	Less ascending colon postprandial volume and high descending colon volume among IBS compared to healthy controls
Di Palma et al[28], 2011	Italy	Case-control	40	31 ± 7	66.7%	Rectal volume was smaller among IBS patients
Nilsson et al[34], 2015	Denmark	Cross-sectional	25	Not mentioned	All males	No inter-individual and intra-individual variability in colonic volume MRI
Grinsvall et al[38], 2021	Sweden	Case-control	354	27.9 ± 9.9	All females	Low grey matter volume in the posterior insula and superior frontal gyrus with high grey matter volume and cortical thickness in the somatosensory cortex and subcortical regions
Blankstein et al[39], 2010	Canada	Case-control	27	30.85 ± 8.9	All females	Increased gray matter in hypothalamus among patients with IBS, and anterior midcingulate cortical thinning
Chua et al[40], 2017	Taiwan	Case-control	69	36.7 ± 7.7	All females	Supramarginal cortex, middle frontal cortex, and left cuneus showed cortical thinning in IBS patients with a negative correlation with the disease severity
Jiang et al[42], 2013	United States	Case-control	266	34.72 ± 11.12	84.6%	No difference in cortical thickness between IBS patients and control subjects. Cortical thickness decreases in the bilateral subgenual anterior cingulate cortex, and increases in the somatosensory and primary motor cortex among women with IBS
Mao et al[43], 2020	China	Cross-sectional	68	Not mentioned	Diarrhhea predominant subjects	Enlarged caudate nucleus and thalamus, and altered hemispheric asymmetries among diarrhea-predominant IBS patients
Chen et al[44], 2011	Canada	Cross-sectional	26	20-54	All females	Mean fractional anisotropy was observed in IBS patients in the fornix and external capsules
Zhao et al[45], 2018	China	Case-control	30	77.5 ± 6.3	20%	Gray matter volume is low in occipital and frontal lobes, limbic and hippocampus, and high in angular and temporal gyrus, and insula
Icenhour et al[50], 2017	Sweden	Case-control	61	32-36	All females	Resting-state functional connectivity is reduced in the amygdala and insula in IBS patients
Guleria et al[51], 2017	India	Case-control	20	30.5	All males	Homeostatic emotions, autonomic responses to pain, and affective motivation differ in IBS patients compared to controls

IBS: Irritable bowel syndrome; MRI: Magnetic resonance imaging.

Table 2 Risk of bias assessment of the included studies

Ref.	Selection bias	Comparability bias	Outcome	Total score
Klinge et al[19], 2022	3	1	3	7
Lam et al[20], 2016	4	2	3	9
Pritchard et al[21], 2014	3	1	3	7
Di Palma et al[28], 2011	3	2	2	7
Nilsson et al[34], 2015	3	2	2	7
Grinsvall et al[38], 2021	4	2	3	9
Blankstein et al[39], 2010	3	2	3	8
Chua et al[40], 2017	3	2	3	8
Jiang et al[42], 2013	3	2	2	7
Mao et al[43], 2020	3	2	3	8
Chen et al[44], 2011	3	2	2	7
Zhao et al[45], 2018	3	2	3	8
Icenhour et al[50], 2017	3	2	3	8
Guleria et al[51], 2017	3	2	2	7