ABSTRACT
Objective To investigate the correlation between posterior perianal abscess and thickness of the puborectalis muscle by magnetic resonance imaging.Methods Sixty-three patients with a low-position posterior perianal abscess (the low-position group),44 patients with a high-position posterior perianal abscess (the high-position group) and 46 healthy volunteers (the control group) were enrolled in this study.In the lithotomy position,MRI was performed to measure the thicknesses of the puborectalis muscle at the 5,6 and 7 o'clock positions of the rectum.Results The thickness of puborectalis muscle at 5,6 and 7 o'clock points in the control group was (5.5 ±0.8),(9.0 ±0.7),(5.4 ±0.6) mm,while that in the low-position group was (5.4 ± 0.7),(10.0 ± 0.9),(5.5 ± 0.7) mm,and that in the high-position group was (7.3 ± 1.0),(11.7-1.2),(7.5 ±0.9) mm,respectively.The thicknesses of the puborectalis muscle at the 5,6,and 7 o'clock positions of the rectum in the lithotomy position were compared between the control group and the low-position group.The difference in the thickness at the 6 o'clock position was statistically significant(t =6.492,P ＜ 0.05),but there were no significant differences at 5 and 7 points (t =-0.719,0.633,P＞0.05).The thicknesses of the pubqrectalis muscle at the 5,6 and 7 o'clock positions of the rectum in the lithotomy position were compared between the control group and the high-position group,and the differences were statistically significant at each position (t =9.476,12.875,13.649,P ＜ 0.05).Simultaneously,the differences between the low-position group and the high-position group were statistically significant(t =-11.206,-7.835,-13.361,P ＜ 0.05).Conclusions Magnetic resonance imaging can diagnose perianal abscess in different parts by measuring the thickness of puborectal muscle,which provides strong evidence for early intervention treatment,so as to improve the therapeutic effect and reduce post-operative anal fistula.