Diagnostic ultrasound ( PDFDrive )

CHAPTER 15 The Uterus 529
Infundibulum
Ovarian
vessels
Fimbriae
Ovary
Fallopian
tube
Cornua
Ovarian
ligament
Uterine
fundus
Cervix
Uterine
body
Isthmus
Broad
ligament
Mesosalpinx
Ampulla
Mesovarium
FIG. 15.1 Normal Gynecologic Organs. Diagram of uterus, ovaries,
fallopian tubes, and related structures. On left side of the image, the
broad ligament has been removed.
the vaginal walls and the surface of the cervix called the
vaginal fornix.
he arterial blood supply to the uterus comes primarily from
the uterine artery, a major branch of the anterior trunk of the
internal iliac artery. he uterine artery ascends along the lateral
margin of the uterus in the broad ligament and, at the level of
the uterine cornua, runs laterally to anastomose with the ovarian
artery. he uterine arteries anastomose extensively across the
midline through the anterior and posterior arcuate arteries, which
run within the broad ligament and then enter the myometrium. 1
he uterine plexus of veins accompanies the arteries.
he uterus is usually best imaged with TVS, with as high a
frequency as possible that also allows sound to adequately
penetrate the uterus. However, scanning with TAS is oten helpful
when the uterus is enlarged and/or ibroids are located very
superiorly or laterally; in such instances TVS alone may miss
important indings. hus it is important to look, albeit sometimes
briely, with TAS regardless of the degree of fullness of the urinary
bladder.
Advantages of Transvaginal Sonography
Suspensory
ligament of
ovary
Use of higher-frequency transducers with better resolution
Examination of patients who are unable to ill their bladder
Examination of obese patients
Evaluation of a retroverted or retrolexed uterus
Better characterization of the internal characteristics of a
pelvic mass
Better detail of a pelvic lesion
Better detail of the endometrium
Doppler ultrasound evaluation, most oten with conventional
color Doppler or power Doppler, is helpful in some patients. It
can be used to evaluate for the presence of vascular low and in
select cases can provide an assessment of the degree and character
of vascularity. As true for any application of color or power
Doppler imaging, small pixels of color that are not part of a
distinct vessel should have spectral Doppler evaluation to distinguish
arterial or venous low from noise.
hree-dimensional ultrasound (3-D ultrasound), usually
performed with a transvaginal transducer, is most useful for
evaluating müllerian anomalies of the uterus and for assessment
of abnormal position of an intrauterine device (IUD). 2 3-D
ultrasound may also be helpful in other instances such as deining
the relationship of uterine lesions to the endometrial cavity and
may be useful to document indings during sonohysterography
(SHG).
Sonohysterography can provide assessment of endometrium
or submucosal myometrial lesions, by distending the endometrial
cavity. Most studies on infusion techniques have used sterile
saline. 3-6 However, gel infusion is now also being used at some
centers. 7,8 SHG is not routinely needed but may be helpful if the
endometrium is not adequately evaluated by TVS or TAS and
may also be helpful in women with abnormal bleeding when a
focal lesion is not visualized sonographically. Other indications
may include evaluation of endometrial or intracavitary abnormalities
detected by TVS, infertility, 9 suspected congenital uterine
malformations, 10 and evaluation of women taking tamoxifen. 11
he procedure involves placement of a sterile speculum,
cleansing of the external cervical os with an aseptic solution,
and placement of a sterile catheter through the cervix into the
endometrial cavity. Several catheters are available, including some
with a balloon (to help prevent leakage of the saline back out
the cervix) and some without a balloon. If a balloon catheter is
used, it should also be illed with saline, as using air may obscure
part of the endometrium. Once the speculum has been removed
and the transvaginal transducer inserted, sterile saline is slowly
injected during ultrasound observation while fully scanning the
entire endometrial cavity. If a balloon catheter is used, one should
be careful that it does not obscure part of the endometrium; this
generally requires delation of the balloon at the end of the
procedure. For premenopausal women, SHG should generally
be performed at about day 4 to 10 of the menstrual cycle, when
the patient is no longer bleeding but is still early in the menstrual
cycle when the endometrium tends to be thin, allowing for
avoidance of normal changes in the latter part of the menstrual
cycle that can simulate pathology. 12 In postmenopausal women
receiving sequential hormone replacement therapy (HRT), SHG
is performed shortly ater the monthly bleeding period. In
postmenopausal women not receiving HRT, the procedure can
be performed at any time. SHG should not be performed in
patients who are pregnant or who have acute pelvic inlammatory
disease. Prophylactic antibiotics may be considered in some
women, such as those with chronic pelvic inlammatory disease, 12,13
including those in whom a hydrosalpinx is discovered at the
time of the study.
Other sonographic methods are used infrequently. Transrectal
ultrasound may occasionally be useful to evaluate portions of
the uterus if TVS is inadequate, if the patient is a virgin, or if
additional imaging is needed for better assessment of the endometrium
or pelvic loor. 14,15 Translabial or transperineal scanning,
although helpful for abnormalities of the pelvic loor, 16 is rarely
useful to evaluate the uterus in a nonpregnant patient. Use of