Diagnostic ultrasound ( PDFDrive )

534 PART II Abdominal and Pelvic Sonography
FIG. 15.6 Calciications at Endometrial/Myometrial Interface. Sagittal TVS shows a few punctate echogenic foci (arrows), likely due to calciications,
at the interface of the myometrium and endometrium. This inding is of doubtful importance and may be related to prior uterine
instrumentation.
proceeds in either a cephalad or a caudal direction or both. 51,52
he median septum formed by the medial walls of the müllerian
ducts then resorbs, leaving a single uterine cavity.
Arrested development of the müllerian ducts, failure of fusion
of the müllerian ducts, and/or failure of resorption of the median
septum results in variable forms of müllerian duct anomalies
(MDAs). MDAs have an estimated prevalence ranging from up
to 6% in the general population to up to 15% in populations
with recurrent pregnancy losses. 53 Whereas minor anomalies
(arcuate uterus with just a mild fundal indentation) probably
have no clinical consequence, others are associated with pregnancy
loss (septate uterus) 54 and various obstetric complications such
as premature delivery (bicornuate uterus).
he anomalies are typically categorized based on their embryology
and morphology, and the most commonly used classiication
is one from 1988 by the American Fertility Society, now known
as the American Society for Reproductive Medicine 55 (Fig. 15.9).
Failure of fusion of the müllerian ducts results in uterus didelphys
or bicornuate uterus, and failure of resorption of the uterine
septum results in a septate uterus (the most common MDA). 56
Other anomalies may be seen in patients exposed to diethylstilbestrol
(DES) in utero, although this is seen less frequently
now since its use was stopped in the early 1970s. In DES exposure,
sonography may demonstrate a difuse decrease in the size of
the uterus and an irregular T-shaped uterine cavity. 57,58
he aforementioned classiication system is problematic,
however, because vaginal anomalies are not included, not all
anomalies it the classiication, and there are no speciic imaging
features deined for diagnosis. Various imaging criteria have been
proposed. We will focus on the more commonly used criteria,
realizing there is no clear agreement on the best criteria. Alternative
classiication systems of MDAs have been suggested. 59-61 Some
patients will have complex anomalies that do not it neatly into
classiication systems; accurate description of the various components
of the anomaly is important in such cases, with measurements
such as fundal indentation, septal thickness, and myometrial
thickness, being potentially helpful.
he coronal view of the uterus is important for many of the
MDAs (Fig. 15.10, Videos 15.1 and 15.2), particularly when
trying to diagnose the more common anomalies such as septate
uterus. One cannot usually obtain a view of the uterus in its
coronal plane with two-dimensional (2-D) TVS, although
occasionally one can obtain a coronal view of the uterus with
TAS when there is little luid in the urinary bladder, and the
uterus is suiciently antelexed. In general, 3-D ultrasound is
needed for determining the type of MDA. 52,62 A recent metaanalysis
for accuracy and diagnosis of MDAs (based on studies
that predominately used the 1988 classiication system 55 )
showed that the highest degrees of mean diagnostic accuracy
were, in decreasing order, as follows: 3-D ultrasound, 97.6%;
SHG, 96.5%; hysterosalpingography (HSG), 86.9%; and 2-D
ultrasound, 86.6%. 53
he most common distinction to be made in clinical practice
is when the endometrium appears slightly divided on 2-D
ultrasound and one needs to determine whether this is an arcuate,
septate, or bicornuate uterus. his is an important distinction
to make because (particularly for infertility patients) when the
MDA is thought to have reproductive consequences, a septate
uterus will in general be treated surgically (because the septum
may have a poor blood supply and can contain ibrous and/or
myometrial tissue 63,64 and is associated with recurrent miscarriage),
whereas a bicornuate uterus will in general not be treated surgically.
Using the 3-D TVS reconstructed coronal view of the uterus,
one should evaluate the contour of the myometrium in the fundus
of the uterus. If the fundal myometrium is outwardly convex or
has an inwardly concave indentation of less than 1 cm (from a