Diagnostic ultrasound ( PDFDrive )

CHAPTER 16 The Adnexa 569
FIG. 16.5 Fluid in Cul-De-Sac. TVS shows echogenic luid in cul-de-sac
caused by blood.
by the inluence of estrogen. 12,13 Pathologic luid collections in
the pouch of Douglas may be seen in association with generalized
ascites, blood resulting from a ruptured ectopic pregnancy or
hemorrhagic cyst, or pus from infection. Sonography can aid
in diferentiating the type of luid, because blood, pus, mucin,
and malignant exudates usually contain echoes within the luid,
whereas serous luid (either physiologic or pathologic) is usually
anechoic. Clotted blood may be very echogenic, mimicking a
solid mass. 14
Postmenopausal Ovary
Diferentiation of perimenopause and early postmenopause is
oten diicult. he postmenopausal period begins when at least
1 year or more has elapsed since the inal menstrual period. 15
In early postmenopause (1 to 5 years since inal menstrual period)
ovulatory cycles may occur infrequently and folliculogenesis may
continue. Once late postmenopause is reached (more than 5
years since inal menstrual period), 16 folliculogenesis ceases, the
ovary atrophies, and the follicles disappear, with the ovary
decreasing in size with increasing age. 6,17-19 Because of its smaller
size and lack of follicles, the postmenopausal ovary may be diicult
to visualize sonographically (see Fig. 16.3E and F). A stationary
loop of bowel may be mistaken for a normal ovary; therefore
scanning must be done slowly to look for peristalsis (Video 16.1).
However, because the colon does not always peristalse during a
sonographic exam, lack of peristalsis is not suicient for differentiation.
Sonographic visualization of normal postmenopausal
ovaries varies greatly in the literature, from a low of 20% to a
high of 99%, using either the TAS or TVS. 5,17-22 he variation is
likely caused by diferences in technique and length of time since
menopause, and the series with very high percentages of visualization
likely include some loops of bowel rather than ovaries. he
ovary decreases in size with increasing age, and therefore the
ability to see the ovaries decreases as the length of time since
menopause increases. 23 Also, the absence of the uterus may play
a role in the visualization of ovaries that are less likely to be seen
following hysterectomy because of the loss of normal anatomic
landmarks. 23
In 290 postmenopausal ovaries known to be present, Wolf
et al. 23 visualized only 41% of ovaries through use of TVS, 58%
through use of TAS, and 68% using both techniques. Highly
placed ovaries may be out of the ield of view of TVS transducers,
and TAS may not image very small or deeply placed ovaries.
Although nonvisualization of an ovary does not exclude an ovarian
lesion, it can be a fairly reassuring inding since most ovarian
neoplasms are cystic, and an ovarian mass will usually displace
adjacent bowel loops and be more easily visible.
Mean postmenopausal ovarian volume ranges are reported
from 1.2 to 5.8 mL. 4,5,17-21 he mean values in these studies may
be somewhat high because nonvisualized ovaries were not
included. One study assessing 563 patients with normal postmenopausal
ovaries by TVS reported a mean ovarian volume of
2.0 mL with an upper limit of normal of 8.0 mL. 5 A postmenopausal
ovarian volume of more than 8.0 mL should be considered
abnormal. Because normal size varies widely, some authors suggest
that an ovarian volume more than twice that of the opposite
side should also be considered abnormal. 18,20
Postmenopausal Cysts
As patients progress from early to late menopause, small simple
cysts, deined as thin-walled, round or oval anechoic cysts with
posterior acoustic enhancement, no internal solid component
or septation, and no internal color Doppler low, become less
frequently observed. While follicles may still be present in the
early menopause, other cysts may be paraovarian or paratubal
in origin or ovarian surface epithelial inclusion cysts.
One report suggests that simple cysts of all sizes may be seen
in up to 15% of postmenopausal ovaries and are not related to
age, length of time since menopause, or hormone use 23 (Fig.
16.6). Smaller cysts are more frequently seen by TVS with its
improved resolution, but in some women, especially those with
hysterectomy or highly placed ovaries, the cysts may be seen
only by TAS. Most of these cysts either disappear or decrease in
size over time. 24-26 Other reports suggest that even in late menopause,
when folliculogenesis is unlikely, small simple cysts are
seen in up to 21% of women. 27,28
Several studies have shown a very low incidence of malignancy
in unilocular postmenopausal cysts less than 5 cm in diameter
and without septations or solid components. 25,26,29-32 In surgical
lesions that are inclined to be larger cysts and/or those in
postmenopausal patients, 84% of simple ovarian cysts have been
found to be cystadenomas. 33 Although it has been shown that
an ovarian cystadenoma may be a precursor of borderline tumors
(those of low malignant potential and low-grade carcinomas),
there is an extremely slow rate of transformation so that these
lesions can be considered benign and are safe to watch over time
rather than remove surgically. 32,34 Ekerhovd et al. 32 found four
borderline or malignant tumors in 247 postmenopausal women
(1.6%) who underwent surgery for simple ovarian cysts detected
by TVS. hese four tumors were all greater than 7.5 cm in
diameter. It is generally recommended that asymptomatic
postmenopausal women with simple ovarian cysts less than 7 cm