**5.4 Endometriosis of the uterosacral ligaments (USLs)**

USLs are one of the most common targets of pelvic endometriosis, which is diagnosed more frequently in a clinical than in a surgical setting. USLs extend over a mean cranio-caudal distance of 21±8 mm. Three regions of origin have been found: cervix alone, vagina alone, cervix and vagina. Insertion points are the piriformis muscle, the sciatic foramen and the ischial spine [19].

This affliction often elicits pelvic pain, dyspareunia and painful bowel movement.

Women with endometriosis in this site present thick USLs due to endometriotic nodules and subsequently, fibrosis is responsible for cul-de-sac obliteration.

TVUS may provide quantitative information to manage patients with USLs endometriosis [20].

At MRI, involvement of USLs by endometriosis is diagnosed when the ligament appears thickened or shows irregular margins (**Fig. 6**) compared with the margins of the controlateral ligament. T2-weighted images identify all lesions as iso- or hypointense to myometrium, while T1-weighted images are less sensitive due to lesions isointensity to myometrium. The proximal portion of the ligament typically presents with asymmetric nodular thickening.

Fig. 6. Axial (A and B) and coronal (C) T2-weighted images showing irregular thickening of the right Utero-Sacral ligaments (blue circles). On the same image there is infiltration of the rectal serosa (blue circle).

Fat-suppressed T1-weighted images sometimes demonstrate hyperintense spots that correlate with hemorrhagic endometrial implants on the ligament (**Fig. 7**).

Fig. 7. Fat-suppressed T1-weighted images demonstrate hyperintense spots that correlate with hemorrhagic endometrial implants on the ligament (A, B).

USLs are one of the most common targets of pelvic endometriosis, which is diagnosed more frequently in a clinical than in a surgical setting. USLs extend over a mean cranio-caudal distance of 21±8 mm. Three regions of origin have been found: cervix alone, vagina alone, cervix and vagina. Insertion points are the piriformis muscle, the sciatic foramen and the

Women with endometriosis in this site present thick USLs due to endometriotic nodules and

TVUS may provide quantitative information to manage patients with USLs endometriosis [20]. At MRI, involvement of USLs by endometriosis is diagnosed when the ligament appears thickened or shows irregular margins (**Fig. 6**) compared with the margins of the controlateral ligament. T2-weighted images identify all lesions as iso- or hypointense to myometrium, while T1-weighted images are less sensitive due to lesions isointensity to myometrium. The proximal portion of the ligament typically presents with asymmetric

**A A B** 

Fig. 6. Axial (A and B) and coronal (C) T2-weighted images showing irregular thickening of the right Utero-Sacral ligaments (blue circles). On the same image there is infiltration of the

Fat-suppressed T1-weighted images sometimes demonstrate hyperintense spots that

Fig. 7. Fat-suppressed T1-weighted images demonstrate hyperintense spots that correlate

**A B A B** 

correlate with hemorrhagic endometrial implants on the ligament (**Fig. 7**).

with hemorrhagic endometrial implants on the ligament (A, B).

**B C**

This affliction often elicits pelvic pain, dyspareunia and painful bowel movement.

**5.4 Endometriosis of the uterosacral ligaments (USLs)** 

subsequently, fibrosis is responsible for cul-de-sac obliteration.

ischial spine [19].

nodular thickening.

rectal serosa (blue circle).

In patients with USLs involvement adhesions could often develop thus, providing posterior displacement of the uterus and ovaries, angulation of bowel loops, elevation of the posterior vaginal fornix, and loculated fluid collections [21]. At MRI, adhesions are detected when low signal intensity is found within the ligaments.
