Uterus, bicornuate

The diagnosis of bicornuate uterus can be suggested by hysterosalpingography HSG (Fig.1) or ultrasound but the most definitive and most accurate diagnosis is obtained by magnetic resonance. On HSG, two endometrial cavities are identified and the angle between the two cavities should be greater than 90 (Fig.2). However, the measurement of the angle is not a very specific finding, and the differentiation between the bicornuate and the biseptate uterus is often difficult. On ultrasound two endometrial cavities are also identified (Fig.3) with ease, but again, differentiation between the bicornuate and the biseptate uterus is difficult. The importance of differentiation is in treatment planning. Bicornuate uterus, because the septum is composed of myometrium, requires open metroplasty while biseptate uterus, because the septum is collagen, can be dissected through the hysteroscope. On MR scans (Fig.4), the findings of bicornuate uterus are: the intercornual distance is increased; there is an outward fundal concavity compared with the normal convexity; endometrial and myometrial width and ratio are normal; two uterine cornua and two endometrial cavities; are easily identified, and the myometrial characteristics of the septum are accurately diagnosed.

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