Dual plane ultrasonography study of anal canal / 中华超声影像学杂志

ABSTRACT

Objective To identify anal canal structures by dual plane transrectal ultrasound. Methods One anorectal specimen was observed by ultrasonography when needles were placed in different anal muscle layers respectively. Fifty patients with no anorectal or perianal diseases were examined by transrectal ultrasound to verify the sonographic features of anal canal, meanwhile the inner and outer sphincters and longitudinal combination muscle were measured. The ultrasound images of anal canal were compared with MR images. Fifty patients were divided into three groups according to the age: 25- 40 years old, 41 -55 years old,and ＞55 years old. Results The sonographic features of anal canal structures by transrectal ultrasound were identified. Anal canal sonographic images and MR images had consistency. The thickness of inner sphincter in each group was (0.19 ± 0.03)cm, (0.22 ± 0.02)cm, (0.24 ± 0.03)cm respectively,while outer sphincter (0.44 ± 0.03)cm, (0.49 ± 0.04)cm, (0.52 ± 0.04)cm, and longitudinal combination muscle (0.10±0.02)cm,(0.11 ± 0.02)cm,(0.11 ± 0.02)cm. Conclusions Transrectal ultrasound is a simple,efficient and non-invasive method to examine anal canal which can identify anal canal structures clearly.