Introduction Defaecation proctography is the current gold standard for the evaluation of defaecatory dysfunction, which includes the assessment of rectocoele, but entails radiation exposure. Defaecation MRI is an alternative but is expensive and not easily available.
Pelvic floor ultrasound is an emerging imaging modality for the assessment of pelvic floor pathology, including defaecatory dysfunction.
This study aims to;
- assess inter- and intra-rater repeatability of rectocoele assessment by both transperineal ultrasound (USS) and proctography
- compare rectocoele assessment between the two imaging modalities.
Method The images of 66 patients who had had undergone both USS and defaecatory proctography were retrospectively reviewed by four interpreters blinded to clinical symptoms and other imaging results.
Transperineal ultrasound was performed on coughing, squeezing and bearing down. Defaecation proctography was performed with rectal and oral contrast.
Rectocoele measurement on ultrasound was determined by the protrusion of the rectal wall beyond the perineal body into the vagina. Rectocoele measurement on proctography was the distance beyond a single line from the projected anterior rectal wall to the furthermost point of the rectocoele.
Bland Altman analysis was performed to determine agreement.
Results There was excellent inter and intra – rater agreement for rectocoele measurement on proctography (intra-class correlation coefficient 0.91 for both).
There was excellent inter – rater agreement (intra-class correlation coefficient 0.78) and good intra - rater agreement (intra-class correlation coefficient 0.67) for rectocoele measurement on USS.
There was moderate agreement between rectocoele measurement on ultrasound and that on proctography (intra-class correlation coefficient 0.46). There was a strong positive correlation between measurements on ultrasound compared to proctography (correlation coefficient 0.59). Rectocoele measurement was 1.25 cm larger on proctography than on ultrasound.
Conclusion The measurement of rectocoeles on both proctography and ultrasound shows good to excellent inter – and intra – rater repeatability.
There is a good correlation between measurements on ultrasound compared with proctography. Not surprisingly, measurements are larger using proctography where protrusion of the rectal wall is measured. By contrast ultrasound measures the protrusion over the perineal body into the vagina. Clearly, proctography may over-diagnose rectocoele. The next main consideration is how size on each modality correlates with function and clinical symptoms.
Disclosure of interest None Declared.