Background
To establish whether the ultrasound findings of minimal endometriosis are confirmed at laparoscopy and that a correlation can be established as to the anatomical sites in this mild form of the disease.

Aims
Patients with pain and suspicion of endometriosis had an ultrasound scan by a sonologist with expertise in endometriosis as part of their pre‐operative workup.

Measurements and Main results
The clinical histories of 53 patients who had laparoscopy to investigate pelvic pain were reviewed. Ultrasounds were performed between 2012 and 2015 by a single sonologist with expertise in endometriosis assessments. The ultrasound findings were divided into subgroups as follows – presence of uterosacral ligament thickness, thickened pericolic fat, ovarian mobility and focal tenderness. These were compared with operative findings of those patients with superficial endometriosis. Evidence Level 3 – observational studies with controls and health services research that includes adjustment for likely confounding factors.

Results
Seventy‐nine percent (42/53) of the patients had laparoscopic findings consistent with their ultrasound findings (95% CI 68–90%, P < 0.0001). Of the subgroups that we reviewed, uterosacral thickening (P < 0.05) and thickened pericolic fat (P < 0.05) were the most associated with superficial endometriosis at the time of laparoscopy. Conclusion Markers on ultrasound that reliably demonstrated inflammation (thickened uterosacral ligaments and thickened pericolic fat) were shown to be significantly associated with the disease.