Our fertility doctor suggests an Ultrasound, Abdominal Vessels procedure, need second doctor opinion?

Hi, We’ve been having problem getting pregnant and have been seeing a fertility doctor. Every time my wife was around ovulation time she would go to the doctor and receive a intra-vaginal ultrasound. When we received the claim it listed, among others, an expensive procedure called “Ultrasound, Abdominal Vessels”. Is this a necessary exam to establish whether she was ovulating? What is this exam normally used for?