Twin peak sign seen in:
The twin peak sign is characteristic of dichorionic pregnancy and is due to chorionic tissue between the two layers of the ine twin membrane at the placental origin.In monochorionic twins there is no chorionic tissue giving rise to T sign on (refer pgno:180 sheila textbook of obstetrics 2nd edition)
Monochorionic diamniotic
Dichorionic monoamniotic
Conjoined twins
Diamniotic dichorionic
General obstetrics