Thickening of the internal anal sphincter: correlation with external rectal intussusception and associated features at MR proctography and anal manometry

The authors aimed to determine whether the thickness of the internal anal sphincter (IAS) can be reliably measured using endoanal MRI and if IAS thickening is linked to external rectal intussusception and anal manometry measurements. Their findings indicate that IAS thickening is significantly associated with external rectal intussusception and lower anal resting pressures, suggesting a potential relationship between these factors. The study demonstrates that IAS thickness can be consistently assessed via MRI, highlighting its relevance in the context of rectal intussusception.