To perform a pilot diagnostic accuracy study of a novel transvaginal ultrasonography procedure called saline-infusion sonoPODography to predict superficial endometriosis in patients with suspected endometriosis.
A prospective single-center diagnostic accuracy study was performed from September 2019-November 2019. The index test sonoPODography was performed and the results were documented in a standardized fashion. SonoPODography was performed by installing saline into the pouch of Douglas (POD) via an intrauterine balloon catheter to create an acoustic window between the ultrasound probe and surrounding structures. The pelvis was then assessed for the presence or absence of superficial endometriosis using pre-defined features. Direct visualization at laparoscopy and histological assessment of excised endometriosis confirmed the outcome. The diagnostic performance of sonoPODography was evaluated.
42 consecutive participants underwent sonoPODography. Superficial endometriosis was identified by sonoPODography in 24/42 (57.1 %) and in 37/42 (88.1 %) participants by direct visualization at laparoscopy. The overall diagnostic performance of sonoPODography was: accuracy 69.1 %, sensitivity 64.9 %, specificity 100.0 %, positive predictive value 100.0 %, negative predictive value 27.8 %. Amongst those without deep endometriosis/endometriomas/pouch of Douglas obliteration, the diagnostic performance was: accuracy 80.0 %, sensitivity 77.7 %, specificity 100.0 %, positive predictive value 100.0 %, negative predictive value 33.3 %. The pouch of Douglas peritoneum was the most common site of superficial endometriosis.
SonoPODography is a novel ultrasound-based procedure that permits the direct visualization of superficial with respectable diagnostic accuracy. The findings of this pilot study are promising and justify the initiation of a larger outpatient study. SonoPODography may establish new avenues for the non-invasive diagnosis and investigation of endometriosis.

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