• Credits
  • Section Writer: Dr. Om J Lakhani
  • Section Editor: Dr. Om J Lakhani

Support us:

Apple iOS- https://shorturl.at/zBRWY
Android - https://shorturl.at/bgswQ

• Q. Which is the best USG method for the evaluation of menstrual cycles?

  • Transvaginal sonography (TVS)

• Q. What are the things to look for in TVS?

  • Ovarian volume
  • Size and number of ovarian follicles
  • Corpus leuteum in luteal phase
  • Endometrium

• Q. Is full bladder required for TVS?

  • No
  • It is required for a transabdominal ultrasound
  • Ovarian changes

• Q. How is ovarian volume calculated?

  • 0.523 x length x thickness x width

• Q. What is the mean ovarian volume in adult women?

  • 4.9 ml – premenopause
  • 2.2 ml- post menopause

• Q. What is the Upper limit of normal for ovarian volume (2 SD above normal)?

  • 20 ml for premenopause
  • 10 ml for post menopause

• Q. Describe the ovarian follicles?

  • Follicles as small as 2 mm can be detected on ultrasound
  • They are echo-free structures compared to surrounding stroma which is echogenic
  • They are spherical in diameter

• Q. How do the follicles look at various phases of the menstrual cycle?

  • Late luteal phase – folliculogenesis starts
  • Day 5-7 – number of follicles of 2-6 mm are visible
  • Day 8 onwards- dominant follicles of 10 mm and increasing is visible – it grows 2 mm a day
  • Close to ovulation- dominant follicle generally 20-26 mm in size (size may be variable)

• Q. How is ovulation predicted on USG?

  • Size of dominant follicle- generally 20-26 mm in size
  • Presence of cumulus oophrous – triangular shaped
  • Granulosa separates from thecal layer- gives it a crenated appearance
  • Preovulatory pain with dominant follicle on the same side – predicts ovulation
  • Dilated cervical canal with cervical mucus appearing as a stripe
  • Endometrium about 8-12 mm in size

• Q. What happens after ovulation?

  • Immediately after ovulation- corpus hemorraghicum
  • Later- Corpus luteum

• Q. Can the function of CL be evaluated based on TVS?

  • Vascularity and Size of CL correlates with progesterone levels (which is the function of the corpus luteum)

• Q. Which other finding can be seen after ovulation?

  • Fluid in the pouch of Douglas
  • Endometrial changes

• Q. Describe the endometrial changes in the follicular phase?

  • Early follicular phase- a single stripe of endometrium seen
  • Mid follicular- basal level enlarges- ‘triple stripe’ pattern
  • Late follicular- 8-12 mm endometrium

• Q. What are the changes in the Luteal phase?

  • The triple stripe is replaced by a single thick hyperechoic stripe – measures 10-14 mm in size
  • Wave like contraction may be seen in Endometrium

• Q. Does the endometrial thickness predict the outcome of pregnancy?

  • No
  • Doppler studies

• Q. What are the changes in uterine blood flow during menses?

  • High uterine vascular resistance – seen in the follicular phase
  • Reduces close to the ovary
  • Nadir after ovulation and remains low
  • Starts increasing in the late luteal phase again

• Q. What happens to the ovarian blood flow?

  • In the initial phase of the follicular cycle- ovarian blood flow is less- high resistance
  • Resistance starts reducing, and blood flow improves as dominant follicle starts to develop and angiogenesis occurs