Abstract
The aims of this study were to determine whether endoluminal ultrasound (ELUS) could identify various layers of the normal anal canal and to evaluate whether a 10-MHz probe provided better image resolution than a 7-MHz probe. Sonographic anatomy of the anal canal on ELUS was directly correlated with anatomic dissection of various layers (mucosa-submucosa, internal anal sphincter, and external anal sphincter) in cadavers. Sonographic appearance of the anal sphincters was further evaluated in patients by “tagging” various layers using sonodense needles. A higher frequency 10-MHz ultrasound probe (focal length, 1–4 cm) provides improved sonographic images of the anal canal, compared with the 7-MHz probe (focal length, 2–5 cm). ELUS can also successfully identify various structures of the pelvic floor including the puborectalis, urethral sphincter, vagina, and outlines of the pelvis and ischiorectal fossae. Its role in the evaluation of anorectal disorders appears promising.
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References
Milsom JW, Graffner H. Intrarectal ultrasonography in rectal cancer staging and in the evaluation of pelvic disease. Ann Surg 1990;212:602–6.
Beynon J, Foy DM, Roe AM,et al. Endoluminal ultrasound in the assessment of local invasion in rectal cancer. Br J Surg 1986;73:474–7.
Beynon J, Mortensen NJ, Foy DM, Channer JL, Rigby H, Virjee J. Preoperative assessment of mesorectal lymph node involvement in rectal cancer. Br J Surg 1989;76:276–9.
Law PJ, Talbot RW, Bartram CI, Northover JM. Anal endosonography in the evaluation of perianal sepsis and fistula-in-ano. Br J Surg 1989;76:752–5.
Law PJ, Kamm MA, Bartram CI. A comparison between electromyography and anal endosonography in mapping external anal sphincter defects. Dis Colon Rectum 1990;33:370–3.
Law PJ, Kamm MA, Bartram CI. Anal endosonography in the investigation of faecal incontinence. Br J Surg 1991;78:312–4.
Cammarota T, Discalzo L, Corno F, Dalbo F, Fiore F. First experiences with trans-rectal echotomography in perianal abscess pathology. Radiol Med (Torino) 1986;72:837–40.
Goldman S, Glimelius B, Norming L, Pahlman L, Seligson U. Transanorectal ultrasonography in anal canal carcinoma. Acta Radiol 1988;29:337–41.
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Tjandra, J.J., Milsom, J.W., Stolfi, V.M. et al. Endoluminal ultrasound defines anatomy of the anal canal and pelvic floor. Dis Colon Rectum 35, 465–470 (1992). https://doi.org/10.1007/BF02049404
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DOI: https://doi.org/10.1007/BF02049404