A prospective study comparing rectal water contrast-transvaginal ultrasonography with sonovaginography for the diagnosis of deep posterior endometriosis

Abstract

Introduction: Preoperative assessment of deep endometriotic (DE) nodules is necessary to inform patients about the possible treatments and provide informed consent in case of surgery. This study aims to investigate the diagnostic performance of rectal water-contrast transvaginal ultrasonography (RWC-TVS) and sonovaginography (SVG) in women with suspicion of posterior DE.

Material and methods: This prospective comparative study (NCT04296760) enrolled women with clinical suspicion of DE at our institution (Piazza della Vittoria 14 SRL, Genoa, Italy). Exclusion criteria were previous diagnosis of DE by imaging techniques or laparoscopy. All patients underwent RWC-TVS and SVG, independently performed by two gynecological sonologists blinded to the other technique's results. Patients underwent laparoscopic surgery within the following three months; imaging findings were compared with surgical and histological results.

Results: In 208 of 281 (74.0%) patients included, posterior DE was surgically confirmed in rectosigmoid (n = 88), vagina (n = 21), rectovaginal septum (n = 34) and uterosacral ligaments (n = 156). RWC-TVS and SVG demonstrated similar sensitivity (SE; 93.8% vs 89.4%; p = 0.210) and specificity (SP; 86.3% vs 79.4%; p = 0.481) in diagnosing posterior DE. Specifically, both examinations had similar accuracy in detecting nodules of uterosacral ligaments (p = 0.779), vagina (p = 0.688) and rectovaginal septum (p = 0.824). RWC-TVS had higher SE (95.2% vs 82.0%; p = 0.003) and similar SP (99.5% vs 98.5%; p = 0.500) in diagnosing rectosigmoid endometriosis and estimated better infiltration of intestinal submucosa (p = 0.039), and distance between these nodules and anal verge (p < 0.001); only RWC-TVS allowed the estimation of bowel lumen stenosis. A similar proportion of discomfort was experienced during both examinations (p = 0.191), although a statistically higher mean visual analog score was reported during RWC-TVS (p < 0.001).

Conclusions: Although RWC-TVS and SVG have similar accuracy in the diagnosis of DE, RWC-TVS performed better in assessment of the characteristics of rectosigmoid endometriosis.

Keywords: enhanced transvaginal ultrasound; posterior compartment deep endometriosis; rectal water contrast transvaginal ultrasonography; rectosigmoid endometriosis; sonovaginography.

FIGURE 1

Rectal water contrast‐transvaginal ultrasonography. Schematic draw (A). Sagittal plane showing a healthy rectum (B) and the presence of an upper rectal endometriotic nodule (*) bulging to the intestinal lumen (D). Transversal post‐acquisition 3D reconstruction of intestinal lumen without (C) and with (E) the endometriotic nodule. The area of the endometriotic nodule has been subtracted from the area of bowel lumen to obtain the proportion (%) of stenosis. B, bladder; RL, rectal lumen; RM, rectal muscularis; RS, rectal submucosa; RVS, rectovaginal space; U, uterus; USL, uterosacral ligament; VW, vaginal wall

FIGURE 2

Sonovaginography. Schematic draw (A). Sagittal plane (B) and 3D sagittal reconstruction (C) of rectovaginal area; B, bladder; C, cervix; RVS, rectovaginal space; RW, rectal wall; VL, vaginal lumen; VW, vaginal wall

FIGURE 3

Flow chart of the study

FIGURE 4

Sagittal plane showing an endometriotic nodule (*) of the right uterosacral ligament at sonovaginography (A) and rectal water contrast‐transvaginal ultrasonography (B). Transversal post‐acquisition 3D reconstruction (C) showing that the endometriotic nodule does not infiltrate the intestinal wall. C, cervix; R, rectum, RL, rectal lumen; RVS, rectovaginal space; RW, rectal wall; USL, uterosacral ligament; VL, vaginal lumen; VW, vaginal wall

FIGURE 5

Sagittal plane showing an endometriotic nodule (*) of the upper rectum at rectal water contrast‐transvaginal ultrasonography (RWC‐TVS) (A) and sonovaginography (SVG) (B). 3D coronal reconstruction of the intestinal lumen at the level of the nodule (estimated stenosis: 8.7%. (C). Another endometriotic nodule (*) of the upper rectum at RWC‐TVS (D) and SVG (E). C, cervix; RL, rectal lumen; RM, rectal muscularis; RVS, rectovaginal space; U, uterus; VL, vaginal lumen; VW, vaginal wall

FIGURE 6

Bland–Altman plot displaying the difference in measurement of the lesion‐to‐anal‐verge distance between rectal water contrast‐transvaginal ultrasonography (red circles) and sonovaginography (green triangles) in women with rectosigmoid DE. Mean (‐) and 95% limits of agreement (‐‐‐) are shown

FIGURE 7

Endometriotic nodule (*) of the lower part of the lateral vaginal fornix at sonovaginography: sagittal plane (A) and 3D reconstruction (B); colposcopic view of the nodule (C). C, cervix; R, rectum; RVS, rectovaginal space; U, uterus; VL, vaginal lumen; VW, vaginal wall