239 © Springer Nature Switzerland AG 2019 L. A. Stadtmauer, I. Tur-Kaspa (eds.), Ultrasound Imaging in Reproductive Medicine, https://doi.org/10.1007/978-3-030-16699-1_14 Evaluation of Tubal Patency (HyCoSy, Doppler) Kamal Ojha, Tuhina Goel, and Dimuthu Vinayagam Baseline Scan and Hydrosalpinges Assessment of fallopian tubes begins with the baseline scan for fertility assessment. Interstitial part of the tube being the fxed part and within the uterus can easily be identifed with three- dimensional (3D) ultrasound examination of the uterus (Fig. 14.1). Tracing this further the outline can sometimes be clearly seen, but this is not always possible. Ideally, the instillation of dye as described below is the best way to identify the fal- lopian tubes. However, if the distal part of the tube is blocked, then often fuid accumulates in the fal- lopian tube over a period of time, and this is described as hydrosalpinges. This is generally located between the uterus and the ovaries. Typically, it is elongated in shape with partial sep- tae best identifed with a transverse ultrasound examination. Unilateral or bilateral hydrosalpin- ges is associated with low success in women undergoing IVF examination. The walls of the hydrosalpinges are thin with clear fuid and partial septum. Identifying the ovary separately is essen- tial to exclude ovarian cyst. The hydrosalpinges can at times completely surround the ovary. A paraovarian cyst is generally observed on either side of the ovary well clear from the uterus and appears more like an ovarian cyst with no septae. K. Ojha (*) St. George’s University Hospital, NHS Foundation Trust, Department of Obstetrics and Gynaecology, London, UK e-mail: Kamal.Ojha@stgeorges.nhs.uk T. Goel All India Institute of Medical Sciences, New Delhi, India Department of Obstetrics and Gynaecology, Saharanpur, Uttar Pradesh, India D. Vinayagam St. George’s University Hospital, University of London, Cardiovascular Sciences Research Centre, London, UK 14