Diagnostic ultrasound ( PDFDrive )

568 PART II Abdominal and Pelvic Sonography
A
B
FIG. 16.4 Punctate Echogenic Foci in the Ovary. TVS images of two patients. (A) Two tiny echogenic foci in normal-appearing ovary.
(B) Multiple peripheral tiny echogenic foci (back walls of tiny unresolved cysts).
calciications. In another study with histopathologic correlation
in seven normal ovaries with echogenic foci, Muradali et al. 8
showed that these foci are caused by a specular relection from
the walls of tiny unresolved cysts below the spatial resolution
of ultrasound rather than calciication. hese echogenic foci do
not indicate signiicant underlying disease, so no further investigation
or follow-up is necessary. Brandt et al. 9 reported that
echogenic foci with associated shadowing consistent with focal
calciication may occasionally be seen in an otherwise normalappearing
ovary. At histologic analysis, 4 of 17 ovaries analyzed
(24%) were associated with benign neoplasms, whereas the
remaining ovaries were unremarkable. It was proposed that these
represent stromal reaction to previous hemorrhage or infection.
Zeligs et al. 10 recently reported echogenic ovarian foci with atypical
morphologic characteristics and distribution in addition to
extraovarian echogenic foci. hese proved to be calciications
associated with a serous borderline ovarian tumor with extraovarian
noninvasive implants. his inding is unusual, however, as
the vast majority of punctate ovarian calciications without
associated mass are of benign etiology. When there is an associated
mass or morphology or distribution of calciications is atypical,
additional imaging is recommended.
he fallopian tubes are musculomembranous structures
measuring up to 12 cm in length and consisting of the intramural,
isthmic, and ampullary portions. Although documentation of
fallopian tubes is not a routine part of a normal pelvic examination,
at least a portion of each tube can be demonstrated in most
patients. Sonographically, the length of the fallopian tube can
be identiied by its tubular structure containing a linear echogenic
lumen that can be followed to the uterine cornua.
Changes During the Menstrual Cycle
he appearance of the ovary changes with age and phase of the
menstrual cycle. Under the inluence of follicle-stimulating
hormone (FSH), human follicular development begins with a
follicular size of approximately 0.03 mm with potential ovulation
ater more than 150 days of growth. It is only ater follicles reach
approximately 4 mm that they are routinely visualized by
ultrasound. During the menstrual cycle, multiple immature, less
than 1-cm follicles appear in the early follicular phase before
day 10. Subsequently, one or more ovulatory follicles become
dominant, increasing in size to 18 to 25 mm in average diameter.
he average size of the dominant follicle is 20 mm in diameter
at ovulation, which usually occurs on day 14 of a normal 28-day
menstrual cycle. he other follicles become atretic. he disappearance
of the dominant follicle with associated free luid in
the pelvis signiies ovulation. Other, less speciic and sensitive
indings may include irregularity of the cyst wall with internal
echoes. 11 A follicular cyst develops if ovulation does not occur
and follicular growth continues because of the lack of the luteinizing
hormone surge and excessive stimulation by FSH.
Following release of the ovum and collapse of the dominant
follicle, the postovulatory corpus luteum is formed, a crenulated
thick-walled cyst demonstrating peripheral color Doppler signal.
he corpus luteum may bleed internally as a result of vascularization
of the inner granulosa layer following ovulation forming a
hemorrhagic corpus luteum (see Fig. 16.3C and D). As the
corpus luteum ages, it collapses and progressively transforms
into a more solid, fatty structure, a corpus albicans, usually not
well visualized sonographically. However, if pregnancy ensues,
the corpus luteum continues to be maintained for hormonal
support until approximately 10 to 13 weeks’ gestation when
placental hormone production can support the pregnancy.
Fluid in the cul-de-sac (Fig. 16.5) is a normal inding in
asymptomatic women and can be seen during all phases of the
menstrual cycle. Possible sources include blood or luid caused
by follicular rupture, blood from retrograde menstruation, and
increased capillary permeability of the ovarian surface caused