MAGNETIC-RESONANCE-IMAGING OF THE PELVIC FLOOR IN PATIENTS WITH OBSTRUCTED DEFECATION

Background Evacuation proctography and measurements of anorectal physi ology are frequently used to clarify the pathophysiology Of obstructed defaecation. In some patients these tests are normal? despite convinc ing clinical evidence of defaecatory difficulty. The aim of this study was to determine whether magnetic resonance imaging (MRI) could revea l pelvic floor abnormality in patients with obstructed defaecation. Me thods Eleven women with obstructed defaecation, in whom evacuation pro ctography and anorectal physiology were normal, were examined by MRI, using a fast gradient echo sequence. Measurements of pelvic visceral a nd muscular descent were taken at rest and during straining, and compa red with those obtained from 13 asymptomatic volunteers. Results Patie nts with obstructed defaecation had significantly greater pelvic visce ral descent (P<0.05), levator muscle descent (P=0.04), levator plate a ngle change (P=0.003) and increase in the area of the pelvic floor hia tus (P=0.0002) than asymptomatic volunteers. Conclusion MRI demonstrat ed marked pelvic visceral and levator muscle descent in women with obs tructed defaecation, despite normal evacuation proctography and anorec tal physiology. MRI should be considered if these examinations have be en normal.