Purpose: The second Houston valve is used as a surrogate for estimating the position of the peritoneal reflection; however, the concordance between the positions of the valve and peritoneal reflection has not been investigated. This study aimed to clarify this positional relationship.
Methods: The second Houston valve and peritoneal reflection positions were assessed using tomographic colonography and magnetic resonance imaging. In total, 117 patients were enrolled in this study.
Results: The positions of the second Houston valve and peritoneal reflection were nearly concordant, although the space between them ranged from - 20.7 to 33.9 mm. A peritoneal reflection located further from the anal verge than the second Houston valve was defined as a shallow peritoneal reflection. Male sex, high body weight, and a high body mass index were significantly correlated with a shallower peritoneal reflection, as determined by a univariate analysis (sex: P = 0.0138, weight: P = 0.0097, body mass index: P = 0.0311). A multivariate analysis revealed a significantly shallower peritoneal reflection in males than in females (odds ratio: 2.75, 95% confidence interval: 1.15-6.56, P = 0.023).
Conclusions: The second Houston valve located near the peritoneal reflection can be a useful surrogate marker for estimating its position. In relatively heavy males, the peritoneal reflection is located more cranially than the second Houston valve.
Keywords: CTC; MRI; Peritoneal reflection; Rectal cancer; Second Houston valve.
© 2022. The Author(s) under exclusive licence to Springer Nature Singapore Pte Ltd.