Name : firoozeh.farnaz
Family : ahmadi.akhbari
Affiliation :Department of Reproductive Imaging at Reproductive Biomedicine Research Center, Royan Institute for
Academic Degree : radiologist
Genital Female Imaging
Gender : Female
Age : 30
A 30 year old woman with 2 recurrent abortions referred to imaging department of Royan institute for further evaluation of infertility by HSG.
HSG demonstrates two narrowly diverting cavities, yielding a V-shape configuration with relatively straight medial borders. The angle formed by the medial borders of two uterine hemi-cavities is 90°(Fig1). Differentiation between septate and bicorn uterus is difficult so the sonography is helpful. In transverse view of a uterus, two island of endometrium with myometrium between them is depicted(Fig2). 3D US in mid-coronal plane showing two endometrial cavities and smooth configuration of uterine fundus.(Fig 3)
septate and bicorn uterus
Discussion (Related Text)
The septate uterus is the most common Müllerian duct anomaly. This anomaly composes approximately 35% of Müllerian duct anomalies. It is associated with some of the poorest reproductive outcomes and has the highest association with recurrent spontaneous abortion .Data from numerous case indicate that the spontaneous miscarriage rate associated with a septate uterus is approximately 65%.During the first trimester of pregnancy, the risk of spontaneous abortion in these patients is between 28% and 45%.Spontaneous abortion rates are reported to range from 28% to 35% in bicorn uterus. HSG of the septate uterus can be used to evaluate the size and extent of septa; however, the diagnostic accuracy of HSG alone is only 55% for differentiation of septate from bicornuate uteri. In septate uterus,the angle formed by the medial borders of two uterine hemicavities is 75°,although some investigators have used 60° as a cut-off value(Fig4). An angle of more than 105° is more consistent with bicornuate uteri(Fig 5). Unfortunately, the majority of angles of divergence between the horns fall within this range and considerable overlap between the two anomalies is noted. Leiomyomas or adenomyosis within the septum may cause secondary distortion and widening of the angles of divergence of the uterine horns. It has been reported that when US is used in conjunction with HSG, the correct diagnosis can be made in 90% of cases. Traditionally, any uterus where 2 endometrial islands were separated by myometrium in 2D transverse section was often erroneously called a bicornuate uterus (Fig6). One of the most important benefits of 3DUS is the ability to display planes that cannot be acquired by direct transducer application to the patient. Consequently, these planes are reconstructed from within the volume and include the most important aspect of the female pelvis: the coronal view.3D US is very helpful in delineating the outer contour of the fundus relative to the uterine lumen (Fig7). In patient with a septate uterus, the outer contour of the fundus is convex. In those with a bicornuate uterus the fundal counter is indented or heart-shaped.(Fig8) 3DUS and MRI are helpful for HSG to diagnose this Müllerian duct anomaly because these modalities permit evaluation of the outer uterine contour as well as the dividing septum. Classification criteria for US differentiation of septate from bicornuate uteri. A, When apex (3) of the fundal external contour occurs below a straight line between the tubal ostia (1, 2) or, B, 5 mm (arrow) above it, the uterus is bicornuate. C, When apex is more than 5 mm (arrow) above the line, uterus is septate.
-C. Fleischer, Sonography in Gynecology and Obstetrics: Just the Facts. 2003,1st edition.
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