Accuracy of sonography for non‐invasive detection of ovarian and deep endometriosis using #Enzian classification: prospective multicenter diagnostic accuracy study
Authors: Montanari E. , Bokor A. , Szabó G. , Kondo W. , Trippia C. H. , Malzoni M. , Di Giovanni A. , Tinneberg H. R. , Oberstein A. , Rocha R. M. , Leonardi M. , Condous G. , Alsalem H. , Keckstein J. , Hudelist G. 
Published: December 2021

Objective

To compare the preoperative detection of endometriosis using transvaginal sonography (TVS) supplemented by transabdominal sonography (TAS) with surgical assessment of disease, using the #Enzian classification for endometriosis.

Methods

This was a prospective multicenter diagnostic accuracy study of women undergoing TVS/TAS and radical surgery for deep endometriosis (DE) at different tertiary referral centers. The localization and grade of severity of the endometriotic lesions and adhesions were described according to the criteria of the #Enzian classification, both at preoperative ultrasound examination and during surgery. According to the #Enzian classification, the small pelvis is divided into three compartments for DE: A (rectovaginal septum and vagina); B (uterosacral and cardinal ligaments, parametrium and pelvic sidewalls); and C (rectum). In addition, further locations (F) are classified as adenomyosis (FA), urinary bladder involvement (FB) and ureteric involvement with signs of obstruction (FU). Other intestinal locations (FI) and other extragenital locations (FO) are also included. Ovarian endometriosis and adhesions at the level of the tubo‐ovarian unit are listed as O and T, respectively. The #Enzian grade of severity (Grade 1–3) was determined for #Enzian compartments O, T, A, B and C based on the size of the lesion or the severity of the adhesions. Concordance between preoperative assessment using TVS/TAS and evaluation at surgery was assessed. The sensitivity, specificity, positive and negative predictive values and accuracy of TVS/TAS in the detection of endometriotic lesions/adhesions in the different #Enzian compartments were calculated.

Results

In total, 745 women were included in the analysis. Preoperative TVS/TAS and surgical findings showed a concordance rate ranging between 86% and 99% for the presence or absence of endometriotic lesions/adhesions, depending on the evaluated #Enzian compartment. The concordance rate between TVS and surgery ranged between 71% and 92% for different severity grades, in #Enzian compartments O, T, A, B and C. Determining the presence or absence of adhesions at the level of the tubo‐ovarian unit and classifying them accurately as Grade 1, 2 or 3 on TVS was more difficult than determining the presence and severity of endometriotic lesions in #Enzian compartments O, A, B and C. The sensitivity of TVS/TAS for the detection of endometriotic lesions ranged from 50% (#Enzian compartment FI) to 95% (#Enzian compartment A), specificity from 86% (#Enzian compartment Tleft) to 99% (#Enzian compartment FI) and 100% (#Enzian compartments FB, FU and FO), positive predictive value from 90% (#Enzian compartment Tright) to 100% (#Enzian compartment FO), negative predictive value from 74% (#Enzian compartment Bleft) to 99% (#Enzian compartments FB and FU) and accuracy from 88% (#Enzian compartment Bright) to 99% (#Enzian compartment FB).

Conclusions

The localization and severity of endometriotic lesions/adhesions, as described and classified according to the #Enzian classification, can be diagnosed accurately and non‐invasively using TVS/TAS. The #Enzian classification provides a uniform classification system for describing endometriotic lesions, which can be used both at TVS/TAS and during surgical evaluation. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.