RELIABILITY AND VALIDITY STUDIES OF ENDOLUMINAL ULTRASONOGRAPHY FOR ANORECTAL DISORDERS

PURPOSE: Endoluminal ultrasonography (ELUS) is accurate in the assessm ent of penetration through the rectal wall by carcinoma. Clinical stud ies were performed to determine the reliability and validity of ELUS. METHODS: The interobserver reliability among four observers with varyi ng experience with ELUS was determined for staging the penetration of rectal cancer through the rectal wall. The ability of ELUS to change t he clinical management of the referring clinician (comprehensiveness) was assessed on all referrals over a six-month period. RESULTS: The re liability of ELUS for staging rectal cancer demonstrated only fair to moderate correlation (weighted kappa range, 0.22-0.47). The accuracy o f ELUS compared with surgical pathology demonstrated a learning curve proportional to the experience of the observer. In 45 percent of refer rals, ELUS changed the clinical management of pa patients and in 76 pe rcent of referrals the clinician's confidence in the diagnosis and man agement of patients was altered. ELUS was more likely to change the ma nagement of patients with pelvic pouch sepsis (70 percent) and early n eoplastic lesions (57 percent) than in more advanced neoplastic lesion s (40 percent), perianal Crohn's disease (40 percent), complex noninfl ammatory bowel disease sepsis (33 percent), and incontinence (31 perce nt). CONCLUSIONS: ELUS has the ability to change the clinical manageme nt of a variety of anorectal conditions. However, for neoplasia the in terobserver reliability is only moderate and a learning curve exists.