Liverpool Ultrasound Pictorial Chart: the development of a new method of documenting anal sphincter injury diagnosed by endoanal ultrasound.

OBJECTIVE

To develop and validate a pictorial chart that documents ultrasound examination of the anal sphincter.

DESIGN

A new pictorial chart (Liverpool Ultrasound Pictorial Chart [LUPIC]) depicting the normal anatomy of the anal sphincter was developed.

METHODS

To validate LUPIC, two observers documented the findings of 296 endoanal scans. Reliability was assessed between observers using kappa agreement for presence and position of sphincter defects. To validate the use of LUPIC by different observers, a video of ten endoanal ultrasound scans was reviewed by our local expert (gold standard). Seven clinicians underwent test-retest analysis. Kappa agreement was calculated to assess intra-observer and gold standard versus observer agreement for the overall presence of sphincter defects and compared with the gold standard. Complete agreement for the position and level of sphincter defects was assessed for the five abnormal scans.

MAIN OUTCOME MEASURES

Excellent agreement between the two observers was found for the presence (kappa 0.99), position and level of external anal sphincter defects documented using LUPIC. The intra-observer and gold standard versus observer kappa values of experienced clinicians (A-E) showed good agreement for the overall presence of sphincter defects. Complete agreement for the position and level of sphincter defects was found in 23 of 35 (66%) observations.

CONCLUSIONS

LUPIC is designed and validated method of documenting anal sphincter injury diagnosed by endoanal ultrasound. Standardisation of endoanal ultrasound findings by using LUPIC may help correlate the degree of damage with patient symptoms.