Congenital uterine anomalies: A resource of diagnostic images, Part 1

INTRODUCTION

Steven R. Goldstein, MD, CCD, NCMP
Professor, Department of Obstetrics and Gynecology, New York University School of Medicine; Director, Gynecologic Ultrasound; and Co-Director, Bone Densitometry, New York University Medical Center, New York

In this month’s Images in GYN Ultrasound, Drs. Stalnaker and Kaunitz have done an excellent job of discussing the various uterine malformations as well as characterizing their appearance on 3D transvaginal ultrasound.

Unfortunately, many women are still subjected to the cost, inconvenience, and time involvement of magnetic resonance imaging (MRI) in cases of suspected uterine malformations. The exquisite visualization of 3D transvaginal ultrasound, so nicely depicted in this installment of Images in GYN Ultrasound, allow the observer to see the endometrial contours in the same plane as the serosal surface. This view is not available in traditional 2D ultrasound images. Thus, it is akin to doing laparoscopy and hysteroscopy simultaneously in order to arrive at the proper diagnosis. Although not mandatory, when such 3D ultrasound is performed late in the cycle, the thickened endometrium acts as a nice sonic backdrop to better delineate these structures. Alternatively, 3D saline infusion sonohysterography can be performed.

As more and more ultrasound equipment becomes available with 3D capability as a standard feature, clinicians who do perform ultrasonography will find that obtaining this “z-plane” is relatively simple and extremely informative, and can and should be done in cases of suspected uterine malformations in lieu of ordering MRI.

Congenital uterine anomalies: A resource of diagnostic images, Part 1

Michelle L. Stalnaker Ozcan, MD
Assistant Professor and Associate Program Director, Obstetrics and Gynecology Residency, Department of Obstetrics and Gynecology at the University of Florida College of Medicine–Jacksonville

Andrew M. Kaunitz, MD
University of Florida Research Foundation Professor and Associate Chairman, Department of Obstetrics and Gynecology at the University of Florida College of Medicine–Jacksonville. Dr. Kaunitz is a member of the OBG Management Board of Editors.

Uterine malformations make up a diverse group of congenital anomalies that can result from various alterations in the normal development of the Müllerian ducts, including underdevelopment of one or both Müllerian ducts, disorders in Müllerian duct fusion, and alterations in septum reabsorption. How common are such anomalies, how are they classified, and what is the best approach for optimal visualization? Here, we explore these questions and offer an atlas of diagnostic images as an ongoing reference for your practice. Many of the images we offer will be found only online at obgmanagement.com.

How common are congenital uterine anomalies?
The reported prevalence of uterine malformations varies among publications due to heterogeneous population samples, differences in diagnostic techniques, and variations in nomenclature. In general, they are estimated to occur in 0.4% (0.1% to 3.0%) of the population at large, 4% of infertile women, and between 3% and 38% of women with repetitive spontaneous miscarriage.¹

Classical classification
A classification of the Müllerian anomalies was introduced in 1980 and, with few modifications, was adopted by the American Fertility Society (currently, ASRM). The Society identified seven basic groups according to Müllerian development and their relationship to fertility: agenesis and hypoplasias, unicornuate uteri (unilateral hypoplasia), didelphys uteri (complete nonfusion), bicornuate uteri (incomplete fusion), septate uteri (nonreabsorption of septum), arcuate uteri (almost complete reabsorption of septum), and anomalies related to fetal DES exposure.²

Anomalies also can be categorized in terms of progression along the developmental continuum, taking into account that many cases result from partial failure of fusion and reabsorption: agenesis (Types I and II), lack of fusion (Types III and IV), lack of reabsorption(Types V and VI), and lack of posterior development (Type VII) (FIGURE 1).³

FIGURE 1. Classification of müllerian anomalies Developed by the American Fertility Society (ASRM)
Source: The American Fertility Society classifications of adnexal adhesions, distal tubal occlusion, tubal occlusion secondary to tubal ligation, tubal pregnancies, müllerian anomalies and intrauterine adhesions. Fertil Steril. 1988. 49(6):944-955.

3D ultrasonography offers accurate, cost-efficient diagnosis
Using only 2D imaging, neither an unenhanced sonogram nor a sonohysterogram can provide definitive information regarding the possibility of a uterine anomaly. The fundal contour cannot be evaluated with 2D imaging; likewise, details regarding the configuration of the uterine cavity (or cavities) may not be appreciated with the use of 2D imaging (FIGURE 2).

Figure 2: Normal appearance, but abnormal uteri In sagittal view, a uterus with a congenital anomaly can appear normal. 2D sagittal views of a normal uterus (top), a didelphic uterus (middle), and a sonohysterogram of a septate uterus (bottom).

To fully evaluate the uterine fundal contour and determine the type of ­uterine anomaly, it previously was necessary to obtain magnetic resonance imaging (MRI) or perform laparoscopy. Today, however, 3D coronal ultrasonography (US) can allow for accurate evaluation of fundal contour and diagnosis of uterine anomalies with lower cost and greater patient convenience. Several ­studies have confirmed the high accuracy of 3D US compared with MRI and surgical findings in the diagnosis of uterine anomalies (with 3D US showing 98% to 100% sensitivity and specificity).^4-6