Magnetic Resonance Defecography Criteria for the Diagnosis of Dyssynergic Defecation
- 1NKC Institute of Gastroenterology and Hepatology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand; and Songkhla Thailand
- 2Department of Radiology, Faculty of Medicine, Prince of Songkla University Songkhla Thailand
Abstract
Background/Aims: Evidence regarding the diagnostic value of MR defecography (MRD) for confirming dyssynergic defecation (DD) is limited. We aim to evaluate the diagnostic performance of MRD parameters in identifying patients with DD.
Methods: This retrospective study was conducted at a university hospital. Data from 235 consecutive adult patients with chronic primary constipation who underwent high-resolution anorectal manometry (HR-ARM), balloon expulsion test, and MRD between 2020 and 2024 were analyzed. The diagnostic performance of each dynamic MRD parameter was assessed using HR-ARM combined with balloon expulsion test as the reference standard.
Results: A total of 109 participants (86 females; mean age 53.1 ± 15.3 years) were included, of whom 70 patients (64.2%) were diagnosed with DD. Quantitative dynamic MRD parameters, including the M-line, anorectal angle (ARA), and anal canal width (ACW), demonstrated significantly good discriminatory ability for differentiating patients with DD (all P < 0.05). At cutoff values of 2.0 cm for the M-line at defecation combined with prominent puborectalis muscle or abnormal evacuation of contrast during defecation, 1.6 cm for M-line change, 114° for ARA at defecation, -5° for ARA change, and 10 mm for ACW during defecation, these parameters demonstrated acceptable diagnostic performance, achieving optimal specificities (82.1% to 92.3%), positive likelihood ratios (3.66 to 7.06), and diagnostic odds ratios (8.25 to 14.25). Multivariate analysis identified ARA and ACW at defecation as independent diagnostic predictors of DD (P < 0.05).
Conclusions: These findings support the establishment of practical and reliable MR defecography–based diagnostic criteria for patients with dyssynergic defecation.
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BibTeX
@article{keeratichananont2026magnetic,
title = {{Magnetic Resonance Defecography Criteria for the Diagnosis of Dyssynergic Defecation}},
author = {Suriya Keeratichananont and Kamonwon Cattapan and Jintaporn Heebpet and Siriporn Leelakiatpaiboon and Nisa Netinatsunton},
journal = {Journal of Neurogastroenterology and Motility},
year = {2026},
month = oct,
doi = {10.5056/jnm26025},
url = {https://doi.org/10.5056/jnm26025},
note = {CC BY-NC 4.0},
}
RIS
TY - JOUR
TI - Magnetic Resonance Defecography Criteria for the Diagnosis of Dyssynergic Defecation
AU - Suriya Keeratichananont
AU - Kamonwon Cattapan
AU - Jintaporn Heebpet
AU - Siriporn Leelakiatpaiboon
AU - Nisa Netinatsunton
PY - 2026
DA - 2026/10/31
JO - Journal of Neurogastroenterology and Motility
DO - 10.5056/jnm26025
UR - https://doi.org/10.5056/jnm26025
AB - Background/Aims: Evidence regarding the diagnostic value of MR defecography (MRD) for confirming dyssynergic defecation (DD) is limited. We aim to evaluate the diagnostic performance of MRD parameters in identifying patients with DD. Methods: This retrospective study was conducted at a university hospital. Data from 235 consecutive adult patients with chronic primary constipation who underwent high-resolution anorectal manometry (HR-ARM), balloon expulsion test, and MRD between 2020 and 2024 were analyzed. The diagnostic performance of each dynamic MRD parameter was assessed using HR-ARM combined with balloon expulsion test as the reference standard. Results: A total of 109 participants (86 females; mean age 53.1 ± 15.3 years) were included, of whom 70 patients (64.2%) were diagnosed with DD. Quantitative dynamic MRD parameters, including the M-line, anorectal angle (ARA), and anal canal width (ACW), demonstrated significantly good discriminatory ability for differentiating patients with DD (all P < 0.05). At cutoff values of 2.0 cm for the M-line at defecation combined with prominent puborectalis muscle or abnormal evacuation of contrast during defecation, 1.6 cm for M-line change, 114° for ARA at defecation, -5° for ARA change, and 10 mm for ACW during defecation, these parameters demonstrated acceptable diagnostic performance, achieving optimal specificities (82.1% to 92.3%), positive likelihood ratios (3.66 to 7.06), and diagnostic odds ratios (8.25 to 14.25). Multivariate analysis identified ARA and ACW at defecation as independent diagnostic predictors of DD (P < 0.05). Conclusions: These findings support the establishment of practical and reliable MR defecography–based diagnostic criteria for patients with dyssynergic defecation.
SN - 2093-0879
SN - 2093-0887
ER -