Re: Office gel sonovaginography for the prediction of posterior deep infiltrating endometriosis: a multicenter prospective observational study. S. Reid, C. Lu, N. Hardy, I. Casikar, G. Reid, G. Cario, D. Chou, D. Almashat and G. Condous. Ultrasound Obstet

Linked Comment: Ultrasound Obstet Gynecol 2014; 44: 710–718 The diagnosis of deep infiltrating endometriosis (DIE) by ultrasound has gained attention in the last decade. As a clinician, this is an important step forward in the management of the disease, for two main reasons: (1) clinicians and patients have become more aware of this entity, leading to earlier diagnosis; and (2) an accurate preoperative diagnosis and mapping of DIE may be helpful for surgeons involved in the management of these patients, especially when DIE affects the so-called ‘posterior compartment’. In experienced hands, transvaginal ultrasound (TVS) has become a powerful tool for the diagnosis of DIE1. However, some limitations still exist. For this reason, modified approaches or adjuvant techniques have been proposed2. In this issue of the Journal, Reid and coworkers report on the use of one of these modified approaches, ‘office gel sonovaginography’, for the diagnosis of posterior DIE. This approach involves placing ultrasound gel into the posterior vaginal fornix and then inserting the transvaginal probe. This gel creates an acoustic window between the probe and the surrounding structures, allowing, theoretically, a more detailed assessment of these structures. Two hundred and twenty consecutive women with the clinical suspicion of DIE were evaluated prospectively by two examiners. Laparoscopic findings were used as the gold standard. Definitive data were available for 189 women. The authors found that overall sensitivity, specificity and positive and negative predictive values in the prediction of all posterior compartment DIE (including bowel (rectosigmoid and anterior rectum), vagina, rectovaginal septum and uterosacral ligaments) were 86%, 93%, 83% and 94%, respectively. Specificity was high for all locations, but sensitivity varied depending on location (being as high as 88% for bowel DIE, but as low as 18% in the posterior vaginal wall and rectovaginal septum). Although the authors suggest that this is the first study using this new approach, there is a recently published paper by León et al.3 that reports similar results to those of Reid et al. The main strengths of this study are the significant number of women recruited, the study's prospective design and the strict methodology used. Therefore, the results reported may be considered as being sufficiently robust for proposing this new approach. However, it would be interesting to know whether this approach is actually better than TVS alone or other, simpler, approaches, such as the proposal of Guerriero et al.2 which involves using gel within a finger of a glove. A study comparing these techniques would be advisable. Additionally, in this study only two examiners performed all examinations, the first being an experienced examiner and the second working under the supervision of the first. Thus, as the authors themselves state in their paper, intra- and interobserver reproducibility studies are needed. Furthermore, the question of whether less expert examiners would have similar results to those of expert examiners needs to be addressed. What seems clear is that there is room for improvement for diagnosing DIE involving the vagina and the rectovaginal septum. I think that for this purpose it is possible that office gel sonovaginography using introital three-dimensional ultrasound4 may be worth assessing in the future, in an attempt to improve our ability to diagnose DIE in these locations.