Fig. 1From: Pregnancy prediction via ultrasound-detected endometrial blood for hormone replacement therapy-frozen embryo transfer: a prospective observational studyPower Doppler ultrasound imaging of endometrial and subendometrial blood flow: type-branch. (A) type I - branch<5: the vessels pass through the lateral hypo-echoic band of the endometrium but do not enter the hyper-echoic rim of the endometrium, branch 1. (B) type II - branch<5: the vessels pass through the hyper-echoic rim of the endometrium but do not enter the endometrium, branch 4. (C) type III – branch <5: the vessels enter the endometrium, branch 4Back to article page