The diagnostic value of magnetic resonance defecography in differentiating evacuation disorders among patients with manometric dyssynergia
摘要
This study aimed to evaluate patients exhibiting a dyssynergic pattern on anorectal manometry (ARM) using Magnetic Resonance Defecography (MRD) to distinguish “true” Dyssynergic Defecation (DD) from structural Non-Dyssynergic Evacuation Disorders (NDED) and to identify the most reliable radiological diagnostic criteria.
Materials and methodsThis retrospective cross-sectional study included 252 patients who exhibited a dyssynergic pattern on ARM. Patients were re-evaluated using MRD and classified into two groups: those confirmed as DD and those reclassified as NDED. The prevalence of structural abnormalities (rectocele, cystocele, descent of the anorectal Junction [DAJ]) and the diagnostic accuracy of MRD parameters (incomplete evacuation, paradoxical sphincter contraction with abnormal anorectal angle [ARA] changes, absence of perineal descent) were analyzed.
ResultsOf the 252 patients diagnosed with dyssynergia by ARM, only 142 (56.3%) were confirmed as DD by MRD, while 110 (43.7%) were diagnosed with NDED. DD was significantly more prevalent in males (69.2%, p = 0.006), whereas structural pathologies were predominant in the NDED group. The presence of cystocele, rectocele, and DAJ significantly reduced the likelihood of a DD diagnosis (p < 0.001). Among diagnostic criteria, the combination of “paradoxical sphincter contraction with abnormal ARA” demonstrated the highest diagnostic validity (Sensitivity: 97.1%, Specificity: 99.1%, Accuracy: 98%). In contrast, incomplete evacuation alone showed high sensitivity (94.3%) but low specificity (45.4%).
ConclusionARM alone is insufficient for diagnosis due to high false-positive rates, particularly in patients with structural abnormalities. MRD plays a crucial complementary role in identifying ‘true’ DD and accurately distinguishing it from structural evacuation disorders. This integrated approach prevents unnecessary biofeedback therapy for patients requiring structural correction.