Transvaginal ultrasonography assessment of ovarian volumes in postmenopausal women

The authors evaluated ovarian volumes by transvaginal ultrasonography at different periods after menopause. Ninety-eight postmenopausal women with an average age of 51.9 years and a oneto eight-year postmenopausal period were studied. The control group consisted of 40 women during menacme with an average age of 31.8 years, who were also submitted to transvaginal ultrasonography to evaluate ovarian volume. There was no significant difference between right and left ovarian volumes in the study groups. There was a significant decrease in measure and standard deviations of the volumes after the first year of menopause (mean volume 2.2 :t 0.9 cm) when compared to the control group (mean volume 6.3 :t 2.0 cm3 ), followed by a slow and gradual shrinking after this phase. Decrease in ovarian volume became significant after the fourth postmenopausal year. Transvaginal ultrasonography demonstrated great importance as an investigative method of ovarian diseases in postmenopausal women.


INTRODUCTION
O varian cancer is an important cause of death due to ~ifficult detection.and diagnosis of its i~itial .
lesIOns.The prognosIs for women who are 10 an advanced stage of the disease remains poor, with a survival rate of 15 percent after a period of 5 years; while women in stage I of the disease have a much better prognosis, with a survival rate of 95 percent in 5 years.'  The difficulty in initially diagnosising ovarian cancer has been attributed to its poor clinical presentation in stages I and II, and to the almost impossible detection of ovarian enlargements in postmenopausal women by bimanual pelvic examination.Therefore, it is imperative to develop adequate detection methods, which would unarguably have a great impact on su rvi val rates, especially in Address for correspondence: Salim Wehba Rua Canario, 1135 -Indian6polis Sao Paulo/SP -Brasil -CEP 04521-005 postmenopausal women, in whom the incidence of ovarian cancer is higher. 2trasonography has been used in postmenopausal women for detection of ovarian enlargements and.neoplasic lesions. 3Transvaginal assessment, a recently developed ultrasonography technique, allows for better visualization of the ovary than conventional abdominal ultrasonography, and seems more efficient in detecting ovarian tumors.
It is a know fact that ovari an si ze decreases progressively throughout menopause.This shrinking is most evident in the ovarican cortical, as a consequence of the acentuated decrease in the growth and maturation of follicles. 4Obliterate arteriolar sclerosis and cortical fibrosis also contribute to the decrease in ovarian size.s As a consequence, ovarian weight decreases 30 percent, according to Block.6' Iwamoto et al. assessed ovari an volume by abdominal ultrasonography and observed a regressive curve that appears after menopause.?
Since transvaginal ultrasonography is more accurate in evaluating the ovarian volume, in this study we evaluated the ovarian volume of women at different periods after menopause, in order to establish normal parameters of ovarian volume in the postmenopausal period.the first year, the difference in ovarian volume once again became significant after the fourth year, as demonstrated by the variance analysis and indicated by a straight line.We studied 98 women during menopause with an average age of 51.9 years, and a 1-to 8-year period of menopause.
Women over 40 years old, with an amenorrhea period of at least one year and high FSH levels, were considered postmenopausal.!!.9 Race and number of gestations were not considered.All patients presented normal clinical and laboratorial conditions.Patients with previous gynecological surgeries, and those with pelvic masses (detected either clinically or ecographically) were excluded.No patient was undergoing hormonal replacement therapy.Ultrasonography was performed with a Toshiba SAL-38D and a mechanical endovaginal sector transducer of 5.0 MHz.Ovaries were assessed in three planes and their size calculated with the simplified elliptic formula: length x height x depth x 0.523. 10The ovaries and vessels were identified in all cases and did not show any texture or surface alterations.Statistical analysis was done by the t test with coupled samples; the Kruskall-Wallis test for independent samples; and a regression analysis of variance.The average volumes of right and left ovaries for control and studied groups are listed in Table I.There was no significant difference between right and left ovarian volumes.Therefore, we used randomly, the average right ovarian volume of both study groups for analysis.

PATIENTS AND METHODS
After comparing the right ovarian volume of both groups, a significant difference could be noted in relation to the average and standard deviation of both groups (Table 2).This difference was present in the first year after menopause and is shown in Chart 1.
Ovarian volume in relation to postmenopausal period is shown in Chart 2 and Table 3.After a sharp decrease in The recently introduced transvaginal ultrasonography has improved image resolution through higher frequency transducers and proximity to the pelvic organs, without the limitations of the abdominal technique.13 High frequency (5-7.5 MHz) endovaginal transducers produce clear images that are easier to interpret, and may effectiveley complement the routine bimanual pelvic exam. 14stablishing the limits of measurement of ovarian volume for each period after menopause is of great importance.With such, increases in ovarian volumes or the appearance of anomalous images would require other methods offering a better investigation.lu5 In our study, there was no significant difference between right and left ovaries.However, we noted a significant decrease in ovarian volumes between the studied groups that began in the first year after menopause.• 16 We would also highlight that, after the initial decrease in ovarian size, the shrinking slows down until the fourth year, when it becomes significant, as demonstrated by the regressive analysis of ovarian volume and postmenopausal period.
Malignant tumors of the ovary have a significantly elevated frequency amongst postmenopausal women over Ovarian Volume (RO -cm 3 ) 2.6:t0.Our results show that the ovarian volume before menopause can be predicted.Therefore, the routine use of transvaginal ultrasonography in climacteric women assumes an important role in finding volume and structure modifications, and could reduce in mortality through early diagnosis.
Control groups consisted of transvaginal ultrasonograms of 40 clinically normal women during menacme (age 20-40 years, mean: 31.8 years) treated as outpatients at the Department of Obstetrics and Gynecology of the College of Medical Sciences of the Santa Casa of Sao Paulo.

Chart 1 -Chart 2 -
Average volume and standard deviation of right ovary at menacme (control) and after menopause.DISCUSSIONUltrasonographic study of the female pelvis is an invaluable method of genital assessment after menopause.Abdominal pelvic ultrasonography was first used in early detection of ovarian cancer ll and endometrial thickness. 12WEHBA, S.; FERNANDES, C.E.; FERREIRA, J.A.S. et al. -Transvaginal ultrasonography assessment of ovarian volumes in postmenopausal women Sao Paulo Medical Journal/RPM 114(3): 1152-1155,1996 Volume of right ovary in relation to postmenopausal period.VOLUME RO(CM') 5

Table 2
Average and standard deviation of ovarian volumes in the control and study groups.