Find the endometriomas (T1 bright, T2 shading), then map deep infiltrating disease compartment by compartment — the uterosacral ligaments, torus, rectosigmoid, bladder, ureters — because the map decides the operation.
Orient first
- Endometriosis has three forms: superficial peritoneal (usually invisible on imaging), ovarian endometriomas, and deep infiltrating endometriosis (fibrotic nodules more than 5 mm deep).
- Deep disease is most common behind the uterus: torus uterinus, uterosacral ligaments, rectovaginal septum and the rectosigmoid wall.
- Transvaginal ultrasound by an experienced operator and MRI both map deep disease; bowel and ureteric involvement changes the surgical team.
Acquire the study
- Sagittal, axial and coronal T2; axial T1 and fat-saturated T1; ± DWI and post-contrast.
The manoeuvre
- Fat-saturated T1: endometriomas and haemorrhagic foci (high signal); T2 shading within the cyst.
- Sagittal T2: low-signal nodules at the torus, uterosacral ligaments and rectovaginal septum.
- Rectosigmoid wall on sagittal and axial T2: the "mushroom cap" of muscularis thickening, its length in cm and distance from the anal verge.
- Bladder wall and the ureters: hydroureteronephrosis from ureteric involvement.
- Adenomyosis on T2: junctional zone thickening, high-signal foci.
What confirms it
- Endometriomas and/or deep nodules mapped by compartment with sizes.
What licenses you to exclude it
- Imaging cannot exclude superficial peritoneal endometriosis; a negative study means no endometrioma or deep disease was seen.
The classic misread
- Calling a haemorrhagic functional cyst an endometrioma — T2 shading and multiplicity favour endometrioma; repeat imaging resolves doubt.