Comparison of uterine and tubal pathology identified by transvaginal sonography, hysterosalpingography, and hysteroscopy in female patients with infertility

Diagnostic imaging plays an important role in the assessment of women with infertility. Although no consensus protocol for work up of these patients exists, the majority of infertility patients undergo a baseline TVS and HSG. TVS is used for evaluating ovaries, fallopian tubes, and the adnexa and is a favored imaging modality in the infertility population because it is readily available, relatively low cost, and does not use ionizing radiation. TVS is the test of choice for diagnosing polycystic ovary syndrome [5], and is helpful for identifying endometriosis and the sequelae of PID. In addition, TVS is invaluable for monitoring ovarian folliculogenesis during treatment with ART [6–8]. In contrast, HSG provides information about tubal patency and uterine cavity abnormalities such as anomalies, polyps, synechiae, and adhesions, any of which could interfere with embryo implantation [9]. However, HSG offers limited evaluation of the cervix and myometrium and does carry the small risks of contrast reaction and of ionizing radiation exposure [10]. Besides TVS and HSG, supplemental evaluation with SIS and hysterosalpingo-contrast sonography (HyCoSy) is sometimes performed. These imaging procedures are becoming more popular because of their ability to combine TVS adnexal evaluation with HSG-like assessment of the uterine cavity, without the risks of contrast reactions and radiation exposure [11–13], but are not yet universally available.

MRI of the pelvis offers multi-planar imaging and does not require the use of ionizing radiation. It is an excellent modality for detecting endometriosis [5] and is helpful for determine the nature of uterine duplication anomalies, leiomyomas, and adenomysis [14–18]. MRI is also employed for evaluating intracranial causes of infertility, such as pituitary adenomas. However, due to its high cost and limited access, MRI is not typically used in the infertility assessment except for a specific indication requiring such imaging.

At our institution, we begin the infertility assessment with an HSG. If there is evidence of an abnormal uterine cavity from etiologies such as uterine septa, submucosal fibroids, synchiae, or polyps, HSC is then typically performed [19–21]. The standard practice at our institution is to perform HSC in the office setting, reserving operative HSC and laparoscopy for patients who are not able to tolerate office based procedures and for situations for which surgical correction is required, such as septoplasty for the correction of a subseptate uterus. Hysteroscopy is also preformed prior to ART if there is a 6 month or greater delay between the HSG and ART. TVS is obtained when patients begin ART, and continues during folliculogensis.

Our results indicate that TVS is superior to HSG for detection of myometrial pathology, including fibroids and adenomyosis. These results make intuitive sense, as TVS uses high frequency sound waves to evaluate the 3 dimensional volume and echotexture of the uterine tissue, while HSG uses radiographs and contrast dye to outline the endometrial cavity. By assessing the contour of the contrast-filled cavity, information about the surrounding myometrium can be inferred, but not diagnosed, because the tissue itself is not imaged directly. HSG may detect submucosal fibroids, but other myometrial pathology, such as intramural or subserosal fibroids, are likely to be missed. Similarly, TVS is superior to HSC, which visualizes the walls of the uterine cavity but cannot assess for lesions within the myometrium.

Our results also indicate that HSG is the superior modality for detection of tubal pathology, specifically tubal obstruction. This finding is in keeping with the functional component of HSG, which allows the operator to visualize in real-time contrast medium passing through the tubes and most importantly, spilling into the surrounding peritoneum. TVS can only infer tubal obstruction when a hydrosalpinx is present, therefore obstructed but nondistended fallopian tubes will be missed with sonography alone. Endometrial pathologies, specifically endometrial polyps, were more frequently identified on direct visualization with HSC than on TVS and HSG combined. It is possible that, for some of our patients, the HSC preceded the TVS and/or HSG and, thus, polyps could have been removed by the time of imaging evaluation. While TVS and HSG are both potential screening modalities for endometrial lesions, HSC is required for optimal diagnosis (Fig. 4), and one reason why flexible office hysteroscopy remains the gold standard for endometrial assessment.

a 44 year-old G0P0 female with inability to conceive for 4 years presents for baseline assessment prior to IVF. TVS demonstrates an 11?×?11?×?10 mm echogenic lesion within the left aspect of the endometrial cavity (calipers). Flow was demonstrated within the lesion with color Doppler, raising the possibility of endometrial polyp. b Corresponding HSG demonstrates a depended rounded filling defect within the left aspect of the endometrial cavity, which persisted on multiple projections, suggestive of a polyp. The fallopian tubes are normal in caliber and patent. The patient went on to HSC, where the lesion proved to be a submucosal fibroid

A weakness in our study is that we did not assess SIS as a method to evaluate the endometrium. This procedure is included in some protocols during the work up of women with infertility, but is not part of the routine assessment at our institution. SIS has been shown to be superior to TVS for identifying endometrial abnormalities including polyps and cavity distortion [11, 13, 22–27]. Some reports have also shown SIS to be comparable to the gold standard of HSC for evaulation of intrauterine abnormalities including polyps, submucosal fibroids, adhesions and uterine anomalies, with a sensitivity and specificity for detection of 88 and 94 %, respectively [28, 29]. In addition, none of our patients were evaluated by HyCoSy, a procedure that uses aerated saline or contrast to assess tubal patency with TVS. HyCoSy has been shown to be comparable to HSG with regards to assessing tubal patency, with sensitivity ranges from 75–96 % and specificity from 67–100 % [12, 13, 30, 31]. SIS and HyCoSy can be done in a single visit and together provide information about the uterine cavity and the patency of the fallopian tubes, similar to HSG, but with added information about the myometrium from the TVS component, all without exposure to ionizing radiation or iodinated contrast. Despite these advantages, HyCoSy does not provide anatomical information about the fallopian tubes, which limits its utility.

Given the lack of a single all encompassing imaging tool for accurately diagnosing endometrial, tubal, and myometrial causes of infertility, it could be helpful to outline one step-wise approach for use of the TVS, HSG, and HSC. Although there is tremendous variability between practices, at our institution most infertility patients undergo both a TVS and HSG prior to initiating ART. Others have found that SIS and HyCoSy provide comparable information as TVS and HSG combined. If findings of these tests suggest an abnormality within the uterine cavity, which could prevent implantation of a viable gestational sac, the patient will be referred for a HSC for direct inspection and possible treatment. However, the management of abnormal tubal pathology on HSG will vary depending on plan for reproductive therapy. If the patient is an In-vitro Fertilization (IVF) candidate, tubal obstruction is not of much consequence, as the embryo is directly implanted into the uterus. However, if the patient is not a candidate for IVF, tubal obstruction can be further managed with surgical interventions such as tuboplasty or salpingostomy.