Diagnostic ultrasound ( PDFDrive )

530 PART II Abdominal and Pelvic Sonography
intravenous ultrasound contrast agents to evaluate the uterus is
still in its infancy but there are possible applications in such
areas as endometrial lesions. 17 Elastography could potentially
help in the evaluation of ibroids, adenomyosis, or sarcomas. 18
Both of these techniques need further investigation before routine
clinical use.
NORMAL UTERINE FINDINGS
he uterus is typically divided into at least three sections anatomically,
although precise boundaries may be diicult to determine
with ultrasound. he fundus of the uterus is the most superior
portion of uterus, oten deined as that portion superior to the
ostia of the fallopian tubes. he body of the uterus is the largest
portion and lies between the fundus and the cervix. he term
“isthmus” or “lower uterine segment” is sometimes used, usually
referring to the region where the body of the uterus becomes
slightly thinner just superior to the cervix. he cervix is the
inferior portion of the uterus between the external cervical os
and internal cervical os. he internal cervical os is oten diicult
to precisely locate in the nonpregnant uterus.
he position of the uterus is variable and can change with
the degree of bladder and/or rectal distension (Fig. 15.2). It may
also change during the course of the ultrasound examination in
response to pressure from the transvaginal transducer or pressure
from the examiner’s hand on the lower abdominal wall. he
term “version” is used to describe the sagittal axis of the cervix
with respect to the sagittal axis of the vagina. he term “lexion”
is used to describe the sagittal axis of the uterine body with
respect to the sagittal axis of the cervix. hese are usually subjective
determinations; objective criteria have been suggested but
are not widely accepted. 19 he direction of lexion and version
A
B
C
D
FIG. 15.2 Uterine Positions in the Sagittal Plane. (A) Anteverted, antelexed position on TAS. (B) Retroverted, retrolexed position on TVS.
(C) Anteverted, retrolexed position on TVS. The uterine body and fundus may be poorly seen with such a uterine position, as in this case. (D)
Axial uterine position on TVS. The uterus is usually poorly seen when in this position.