Figure 19b. Didelphic uterus and longitudinal vaginal septum combined with obstructed hymen (class 4). (a) Direct coronal T1-weighted spin-echo image (420/6) shows a markedly distended vagina with altered blood products (hematocolpos); obstruction is at the level of the hymen (arrow). A longitudinal septum (arrowhead) splits the vagina into two compartments, sparing its lowest part, which has a different embryologic origin. (b) Sagittal T2-weighted FSE image (4,000/98) shows that the uterus is connected to each vaginal compartment (only one side is shown).