Ovaries -Volumes at different ages and echogenecity and DF number in healthy fertile women

 

How little we know about “The Ovaries” !!  

Q.1: Shape ?

The normal ovary is ellipsoid in shape and is variable in both location and orientation depending upon the age and parity of the patient as well as the degree of bladder distention.

Q.2: Location and anatomic boundaries? Ans:  In the nulliparous adult female the ovaries  are situated in the ovarian fossa which is adjacent to the lateral pelvic side wall and is bounded by the obliterated umbilical artery anteriorly the ureter and internal iliac artery posteriorly and the external iliac vein superiorly . the inferior aspect of the ovary is slightly smaller than the superior or tubal aspect and is bound to the uterine  cornua by the ovarian ligament which lies within  the broad ligament . The lateral  surface of the ovary is in  contact with  the parietal peritoneum lining the ovarian fossa and most of  the medial surface is covered by the fallopian tube . The anterior border of the ovary is attached to the mesovarium through  which the vascular channels and nerves pass into the ovarian hilum.

Q.3 : Ovarian volumes: Ovarian volume is calculated by measuring the ovary in three dimensions on two orthogonal planes and using the formula for the prolate ellipse . Ovarian size depends upon age menstrual status pregnancy status body habitus and phase of the menstrual cycle .

Q.4: Ovarian volume in postmeno ages??  Ans: In premenopausal women the mean ovarian volume is 9.8 ml with the highest volumes found in the preovulatory phase and the lowest volumes in the luteal phase.  Normal ovarian volume decreases after the age of 30 years. In one large  study mean  ovarian  volume significantly decreased in each  decade up to age 60 years measuring 6.6 ml in women under 30 years of age 6.1 ml in women 30 to 39 year old  , 4.8 ml at ages 40 to 49 years 2.6 ml at ages 50 to 59 years 1.98 ml at ages 60 to 69 years and 1.85 ml over age 70 years The authors found a statistically significant increased  ovarian size in tall women but no relationship to weight  Despite the small size of the postmenopausal ovary  the majority are detectable by TVS.  

Q.5: How is the appearance of follicles in different phases of cycle ? The normal ovary in women of reproductive  age has a variable appearance  over the course of the menstrual cycle. Developing and immature follicles can be seen throughout the entire menstrual  cycle and appear as anechoic unilocular sharply marginated cysts measuring from 2 to 9 mm.

What happens in day 8? Selection of DF.  By days 8 to 12 of the menstrual cycle one or more dominant follicles will grow to a diameter of approximately 20 to 25  mm and then rupture at ovulation releasing the oocyte.

Q.6. What is the prevalence of second non dominant follicle in healthy women? Ans:   Up to 80% of patients have  a second  non dominant  follicle that becomes almost as large as the dominant follicle.

Q.7; How does  The preovulatory  dominant follicle looks like in imaging?? Ans:   The preovulatory dominant follicle may have a slightly complex appearance with the oocyte and its supporting structures appearing as a ring like structure within the follicle. But following ovulation the corpus luteum evolves from the remnant  of the mature  follicle through a process of cellular hypertrophy and increased vacuolization of the cyst wall.

Q.10 .How does CL looks like in USG?  Ans: A corpus luteum  is typically  visible in the secretory phase of the menstrual cycle and in the first few weeks of early pregnancy . On sonographic imaging the corpus luteum typically has a relatively thick homogeneously echogenic wall the inner margin of which may be slightly irregular with a crenulated appearance .

On color Doppler  the wall of the corpus  luteum often demonstrates a circumferential ring of arterial flow with a low resistance spectral Doppler waveform.

  Internal  echoes are common reflecting variable amounts of internal hemorrhage that occurred at the time of ovulation and occasionally a corpus luteum may be filled with homogenous low level echoes mimicking a solid mass .

Q.11. what is the size of CL??  Ans: There is usually evidence of enhanced through transmission because of the fluid content and there will be no central vascularity typically the corpus luteum  is under 3.0 cm in maximal dimension but rarely it may become larger. If pregnancy does not occur the corpus luteum gradually involutes and atrophies to become the corpus albican which is typically not sonographically identifiable.

 Q.12: Relevance tiny echogenic foci in postmeno women?  Small echogenic foci measuring 1 to 3 mm may be noted in the periphery of otherwise normal appearing ovaries  in approximately half of women undergoing TVS particularly in the perimenopausal age group . These foci often demonstrate ring down artifact and are a benign finding, likely related to the presence of tiny cysts possibly cholesterol or hemosiderin deposition and less likely tiny calcifications. These tiny echogenic foci may come and go underneath  the surface epithelium and should not raise concerns or result in follow up imaging.

Q.13. Ovarian volume in post meno women?  In the postmenopausal patient ovarian size decreased correlating with  hormonal status and length of time since menopause mean postmenopausal ovarian volumes have been reported to range from 1.2 to 5.8 ml with an ovarian volume of greater than 8 ml considered abnormal in all cases.

Some authors have suggested that a unilateral ovarian size twice   that of the opposite side regardless of the size should also be considered abnormal.

Q.15: What is the prevalence of small simple adnexal cysts measuring as large as 3 cm  in postmeno ovaries? Ans:        Even though folliculogenesis has ceased the postmenopausal ovaries are not as quiescent as initially thought small simple adnexal cysts measuring as large as  3 cm have been reported  in up to 15% of postmenopausal  women most of these spontaneously regress on serial sonographic examinations. These simple cysts seen early in menopause most likely represent an occasional ovulatory event  or an atretic follicle.

 However  any anechoic cystic lesion in a postmenopausal ovary should generally be referred  to as a cyst In late menopause although ovulation is rare smaller cysts less than or equal to 1 cm have been reported in up to 21% of women. TVS will detect these cysts more readily than TAS because  of the higher resolution of the higher frequency transvaginal probe . These simple appearing cysts measuring less than 1 cm in maximal diameter do not need further follow up  and whether or not they  are described in the final report can be left  to the discretion of the interpreting physician.