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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5817_Библиотеки_им_академика_М_И_Перельмана-1.pdf
Doppler Ultrasound in the Diagnosis of Fetal Anomalies
Fetal Cardiac Malformations
Figure 11.6 shows the color-coded display of a normal
heart with intact septum. Since display of blood flow
will show changes such as even very small septal de-
Fig.
fects (
reliable definition of structural anomalies of the fetal
heart (Fig. 11.7) in almost all cases between the 18th
and 32nd week of gestation. The nature of gray-scale
B-mode imaging does not allow such a display.
Fetal echocardiography is indicated when:
왘 There is a family history of another child or one
왘 A history of maternal disease or pharmacological or
2
왘 Monitoring of the pregnancy reveals a pathological
왘 The cardiac rhythm is irregular.
11.8), Doppler ultrasound makes possible a
parent having been or currently being affected with
a cardiac anomaly, since there is said to be a somewhat increased risk of familial repetition;
teratogenic substance use increases the fetal risk for
cardiac anomalies;
condition such as fetal malformations, hydrops
fetalis, or oligohydramnios or polyhydramnios;
Fig. 11.6 Color display of the heart. An intact septum is seen
between the two chambers.
114
Fig. 11.7 Color Doppler sonogram of the heart. An ectopic
heart can be seen.
Fig. 11.8 Color sonographic display of a very small septal de-
fect.
Malformations of the Gastrointestinal Tract and the Abdominal Wall
Abdominal wall defects include primarily omphalocele
and gastroschisis. The significance of the differential
diagnosis lies in the fact that omphalocele is associated
with chromosomal aberrations relatively often (up to
50%, depending on the study cited), while there is no
such association aggregation for gastroschisis. Additionally, the morbidity is different in the two malformations, so that it is even more important to differentiate between the two for the management of the pregnancy. Omphalocele features a hernial sac, the defect is
in the midline, and the origin of the umbilical cord lies
11.9). By contrast, a gastroschisis has
in the hernia (
Fig.
blubber
no hernial sac, lies most often laterally to the right of
the midline, and the origin of the umbilical cord is not
included in the malformation (Fig. 11.10). Determining
the site of insertion of the umbilical cord by color Doppler sonography can therefore contribute materially to
distinguishing between the two malformations.
To date color Doppler ultrasound cannot contribute
to the diagnosis of obstructions of the gastrointestinal
tract. However, since color-coded Doppler is not exclusively concerned with blood flow, but can detect any
form of movement eliciting a frequency shift, it can
document increases in intestinal peristalsis (
Fig. 11.11).
Malformations of the Gastrointestinal Tract and the Abdominal Wall
Fig. 11.9a Color Doppler display of a part of the umbilical cord
running within an omphalocele.
Currently it remains unclear whether in the future
Doppler ultrasound can improve the differential diagnosis of uterine perforation.
Changes in the liver that appear as cysts in a grayscale B-mode image are more easily evaluated by color
Doppler ultrasound, since, analogously to the findings
in the brain, the structures can be examined for blood
11.12a, b).
perfusion to see if they are indeed cystic (
Fig.
Tumors such as hemangiomata or intra-abdominal
aneurysms (Fig. 11.13) can for one thing be recognized
as such, and for another—in the case of hemangiomata—be better ascribed to specific areas of the liver.
Fig. 11.9b Color Doppler reveals that the umbilical cord is inserted within the omphalocele.
Obstetric Applications of Doppler Ultrasound
Fig. 11.10 Free intestinal coils in a gastroschisis. The umbilical
cord bypasses the intestinal coils and is inserted in a typical site
directly on the abdominal wall.
pler.
115
컄Fig. 11.11 Display of intestinal hyperperistalsis by color Dop-
blubber
Doppler Ultrasound in the Diagnosis of Fetal Anomalies
2
Fig. 11.12 a Gray-scale sonography displaying cystic structures
in the liver.
Fig. 11.12 b Color Doppler identifies these as engorged blood
vessels.
Fig. 11.13 Display of an aneurysm in the course of the intra-
abdominal part of the umbilical vein.
116
Anomalies of the Urogenital System
The evaluation of the amniotic fluid is an important diagnostic task, since in the second trimester amniotic
fluid reflects the performance of the kidneys. In the
case of a diagnosis of anhydramnios the conclusion
must be that kidney function is absent bilaterally,
which makes the prognosis for the fetus extremely
poor, considering that hypoplasia of the lungs must
then also be expected (Potter syndrome, oligohydram-
11.14). As a rule anhydramnios can
nios sequence) (
only be evaluated satisfactorily by color Doppler sonography, since in the gray-scale B-mode image coils of
umbilical cord are often misinterpreted as pools of
amniotic fluid.
Even the direct evaluation of the kidneys themselves
is simplified in selected cases. Thus, the demonstration
Fig.
blubber
of an intrauterine renal aplasia succeeds only if the absence of the renal aa. can be displayed by color Doppler
Fig. 11.15).
(
In hydronephrosis the evaluation of the Doppler
spectrum, analogous to that of hydrocephalus, can provide some indication of renal function, since the intrarenal pressure can be derived from the Doppler
waveform(
are required to confirm this.
The diagnosis of tumors of the urogenital system can
be simplified by color Doppler ultrasound, since display of their blood supply allows conclusions to be
drawn regarding their malignancy, and their topographic allocation is more successful (Figs. 11.18,
11.19).
Figs. 11.16, 11.17). However, relevantstudies
Anomalies of the Urogenital System
Fig. 11.14 Display of the perfusion of a very large and mal-
formed kidney, perhaps a Potter III polycystic kidney.
Fig. 11.16 Severe hydronephrosis on one side and normally
perfused kidney on the other.
Fig. 11.15 Failure to display the renal arteries provides evidence of renal agenesis.
Obstetric Applications of Doppler Ultrasound
Fig. 11.17 The aorta and iliac bifurcation are displayed. There
is no evidence of renal arteries in the presence of bilateral hydronephrosis. The conclusion is that the pressure in the kidneys
is relatively high.
middle abdomen of the fetus. Color Doppler ultrasound demonstrates that this structure receives no blood and may correspond to a blood-filled ovarian cyst.
blubber
컄Fig. 11.18 A hypoechoic structure can be seen in the lower and
117
Doppler Ultrasound in the Diagnosis of Fetal Anomalies
2
Fig. 11.19 a Display of the intra-abdominal part of the umbilical arteries coursing around the urinary bladder.
Coccygeal Teratomata
Teratomata of the coccyx may contain cystic or solid
portions of various extents and their vascularization
especially may vary. Among other features the prognosis of the malformation depends on its composition
and perfusion. Here the introduction of a color Doppler
adds several decisive diagnostic advantages, since for
one thing it is especially powerful in clarifying the
Fig. 11.19 b The same arteries with ascites.
Figs.
vascularization of the teratoma (
for another it can determine if the volume load has led
to cardiac insufficiency and the extent of its severity.
Coccygeal teratomata also indicate the need to
search for other anomalies, since this abnormality
often accompanies associated malformations and also
chromosomal aberrations.
11.20,11.21), and
118
Fig. 11.20 Coccygeal teratoma, with relatively little perfusion
in this color display.
blubber
Fig. 11.21 Coccygeal teratoma with markedly better perfusion
than in
Fig. 11.20.
Placenta
Malformations of the Umbilical Cord
Because of the capability of Doppler ultrasound, examination of the placenta does not play as great a role
as before its introduction. Calcification of the placenta
is no longer given the same significance as formerly,
Hydrops Fetalis
Doppler sonographic evaluation of the fetal heart contributes decisively to the diagnosis of hydrops fetalis.
When cardiac insufficiency can be demonstrated, extra
Anhydramnios
As explained in the section on renal anomalies, Bmode imaging cannot always distinguish between
oligohydramnios and anhydramnios, since coils of the
umbilical cord may simulate small amounts of amniotic fluid. Only color Doppler examination can identify
the coils of umbilical cord with certainty (Fig. 11.22).
This can be an important factor in the prognosis for the
11.23).
pregnancy (
Fig.
since Doppler sonography can determine the condition
of the fetus, and consequently clarify the effect of the
placental calcification.
strain on the heart by increased blood volume may be
assumed.
Obstetric Applications of Doppler Ultrasound
Malformations of the Umbilical Cord
Malformations of the umbilical cord include the absence of one artery, where only two umbilical vessels
exist, tumors, and aneurysms of the cord. Doppler ultrasound can be helpful but is not essential in the diagnosis of all three malformations. The absence of one
umbilical a. is easily identified in the B-mode image,
since in the cross section of the cord only two lumens
are displayed. In such cases using the color Doppler
may even lead to a misdiagnosis, since in a normal
three-vessel umbilical cord the two arteries may be erroneously seen as one, due to over-regulation if the
blubber
Fig. 11.22 A definitive diagnosis of anhydramnios rather than
oligohydramnios can only be made by color Doppler ultrasound, as on a gray-scale image coils of the umbilical cord can
resemble small hypoechoic pools of amniotic fluid.
velocity of the color Doppler is not set in the optimal
range.
Color Doppler examination can be very helpful in the
differential diagnosis of aneurysms, cysts, and tumors,
since it can demonstrate blood flow in an aneurysm,
Fig.
and exclude it in a cyst or tumor (
Beyond this color Doppler sonographic display of the
umbilical cord can also facilitate the clarification of
cord changes in feto−fetal transfusion syndromes
(FFTS), in multiple pregnancies (Fig. 11.25), and in the
diagnosis of a cord looped around the neck (Fig. 11.26).
11.24).
119
Doppler Ultrasound in the Diagnosis of Fetal Anomalies
Anhydramnios
2
Display of kidneys by abdominal and
vaginal ultrasound
Color Doppler ultrasound
of renal aa.
Renal agenesis
a
Doppler ultrasound of umbilical a.,
arcuate aa./uterine aa. (color)
+–
+–
Ultrasound
morphology
Karyotype
Amniotic rupture?
Normal Abnormal
Amnion filling
Perfusion
impaired,
but possibility of
triploidy,
trisomy 13/18
120
b c
d e
Fig. 11.23a−e Algorithm of procedures and typical findings in
anhydramnios.
a Algorithm of diagnostic procedures for anhydramnios.
b Color Doppler ultrasound display of renal aa. and aorta with
bifurcation.
c Bladder displayed by color Doppler sonography. Minimally
filled bladder between the umbilical arteries.
d Aorta with absent renal arteries in renal agenesis displayed
by color Doppler sonography.
e Potter syndrome: Bilateral renal agenesis. Aortic bifurcation
showing hypoplastic right common iliac a. and hypoplastic
adrenals in the renal bed.
blubber
Doppler Ultrasound Diagnosis of Malformations in Early Pregnancy
Fig. 11.24 Tumor of the umbilical cord. Color Doppler displays
the vessel running through the tumor.
Fig. 11.26 A triple loop of the umbilical cord displayed by color
Doppler.
Fig. 11.25 Display of the communicating vessel running from
umbilical cord to umbilical cord in twin-to-twin transfusion syndrome (TTTS).
Doppler Ultrasound Diagnosis of Malformations in Early Pregnancy
Indications for Doppler sonography in early pregnancy
must be strictly limited, since a biological effect of
color Doppler sonography in early pregnancy cannot
be ruled out. However, the procedure simplifies diag-
nosis in two important malformations, namely in the
demonstration of conjoined twins (Fig.
in a twin pregnancy with one acardius (Fig. 11.28,
11.29).
Obstetric Applications of Doppler Ultrasound
11.27a, b) and
Fig. 11.27 Conjoined twins.
a Twin pregnancy displayed in gray-scale. The display shows a
common trunk.
blubber
b Color Doppler is able to demonstrate in early pregnancy
that the two infants have a common heart.
121
Doppler Ultrasound in the Diagnosis of Fetal Anomalies
a
Fig. 11.28 Twin pregnancy with an acardius.
a Color Doppler can display the vascular link
2
b
b Spectral Doppler demonstrates blood flow in the acardius.
Fig. 11.29 Acardius in the 20th week of gestation. Color Doppler shows reverse flow in the aorta.
122
blubber
12 Multiple Pregnancy and Doppler Ultrasound
Multiple pregnancies are one of the indications for
Doppler ultrasound in obstetrics that are included in
many guidelines, especially when there is discordant
growth of the infants.
Simple monitoring methods used successfully for
single fetuses, such as inspection, palpation, fundal
height, abdominal girth, etc., fail to provide information about an individual infant in a multiple pregnancy.
For this reason ultrasound techniquessuch as cardiotocogram (CTG), ultrasound, Doppler ultrasound, and
color Doppler ultrasound are indispensable aids when
multiple pregnancies are being monitored.
The more closely the multiple fetuses are linked, the
more important becomes the use of biophysical
methods. In the case of dichorionic multiple fetuses
ig.
F
12.1) constrictions in nutritional supply are the
(
primary problem because they may result in discordant or restricted growth. In monochorionic multiple
pregnancies additional problems arise with communications between the fetal circulations such as a
twin-to-twin transfusion syndrome (TTTS), (feto−fetal
transfusion syndrome [FFTS]) or twin reversed arterial
perfusion (TRAP). Finally, in monoamniotic twins
Fig. 12.2) complications play an important role. This
(
chapter will only briefly refer to the special morphological and functional problems of conjoined twins.
Doppler ultrasound is part of the risk assessment in
the second half of pregnancy. Discordant growth is a
specific indication during this time, beside the indications arising during singleton pregnancies. In the
author’s opinion every twin pregnancy, but especially
every monochorionic twin pregnancy, should in itself
be an indication for Doppler ultrasound examination.
The reasons for this will be clear by the end of this
chapter.
Obstetric Applications of Doppler Ultrasound
Fig. 12.1 Display of a dichorionic twin pregnancy. Fig. 12.2 Display of a monoamniotic twin pregnancy.
blubber
123