Figure 5b. Septate uterus. (a) HSG image shows wide divergence of opacified endometrial cavities simulating a bicornuate configuration. (b) Corresponding coronal oblique fast spin-echo T2-weighted MR image (6000/120 [effective]) demonstrates insinuated leiomyoma (long arrow) within the septum, causing exaggerated separation of cavities. Note lateral wall myoma with cystic degeneration (short arrow) also causing distortion of left endometrial cavity.