Transcript Slide 1

Placental US
Andrea Jelks, MD
12/8/06
Case of the Day
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18 yo G2 P0101 at 18 weeks by 1st
trimester sono presented for an anatomy
ultrasound
Size = dates
Fetus anatomically normal male
Posterior placenta…
Outline
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Various placental ultrasound findings
Changes with gestational age
 Echolucencies
Others…..
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This image shows:
A)
B)
C)
D)
Source: www.obgyn.ufl.edu
A posterior uterine contraction
which gives a false impression of
placenta previa
An anterior marginal placenta previa
A central placenta previa
A succenturiate lobe on the
posterior uterine wall
(A.) The internal os is poorly seen,
but transvaginal US would almost
certainly show that this placenta
does not cover the cervix
The thick area on the posterior
uterine wall is a localized uterine
contraction.
The impression that there may be a
previa is caused by the posterior
uterine contraction.
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Source: Google images
Another picture
of uterine
contraction
Placenta would
be of normal
thickness if seen
after the UC
abated
Importance of
reimaging after a
few minutes
have elapsed
These images show…
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This is a 21-week-fetus
pregnancy c/b Rh
sensitization.
Hydrops with extensive
edema, ascites,
hydrothorax and
abnormal thickness
of placenta
Placental thickness
judged subjectively
At midposition or cord
insertion 2-4 cm = normal
Source: www.thefetus.net
Normal Placental appearance
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8-20 weeks: uniform echotexture, 2-3 cm
thickness
>20 weeks:
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Measures 4-5 cm thick
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Decidua basalis
Measures 9-10 mm
thickness
Contains maternal
blood vessels
Easy to confuse with
retroplacental
hemorrhage,
especially if
posterior placenta
Fluid side =
chorionic plate
(chorioamniotic
membrane) = bright
specular reflector
Source: www.mysono.com
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Grade 0
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Late 1st trimesterearly 2nd trimester
Uniform moderate
echogenicity
Smooth chorionic
plate without
indentations
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Grade 1
Mid 2nd trimester –
early 3rd trimester
(~18-29 wks)
Subtle indentations
of chorionic plate
Small, diffuse
calcifications
(hyperechoic)
randomly dispersed
in placenta
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Grade 2
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Late 3rd trimester
(~30 wks to
delivery)
Larger indentations
along chorionic
plate
Larger calcifications
in a “dot-dash”
configuration along
the basilar plate
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Grade 3
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39 wks – post dates
Complete indentations of
chorionic plate through to
the basilar plate creating
“cotyledons” (portions of
placenta separated by the
indentations)
More irregular
calcifications with
significant shadowing
May signify placental
dysmaturity which can
cause IUGR
Associated with smoking,
chronic hypertension,
SLE, diabetes
Found in ~20% of
pregnancies at 40 weeks
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Significance of Placental Grade
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N = 1802 low-risk patients at 36 weeks
Grade III placenta found in 3.8% (68/1802).
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Associated with young maternal age and cigarette
smoking, p < 0.01.
PIH: Study group 7.4% (5/68) and 1.56% of controls
(27/1734), p < 0.01.
SGA: 17.6% (12/68) vs. 5.6% (97/1734), p < 0.01.
Conclusion: Ultrasound detection of a grade III
placenta at 36 weeks' gestation in a low-risk
population helps to identify the "at-risk"
pregnancy
McKenna D, Ultrasonic evidence of placental calcification at 36 weeks' gestation: maternal and fetal outcomes. Acta Obstet
Gynecol Scand. 2005 Jan;84(1):7-10.
This placenta would
most likely be
associated with:
A) Fetal hydrops
B) Trisomy 18
C) Lupus anticoagulant
D) Maternal smoking
(A.) This is a very thick, echogenic
placenta in a fetus with hydrops.
- Fetuses with Trisomy 18 have
small placentas.
- Pregnancies with lupus
anticoagulant would have a small or
normal placenta.
- Maternal smoking results in an
echogenic grade III placenta, but not
diffuse thickening and echogenicity
as seen here
Source: www.obgyn.ufl.edu
A)
B)
C)
D)
In the early second trimester
approximately 5% of
placentas appear to cover
the internal os.
80% of cases where previa
is diagnosed in the early
second trimester do not
have placenta previa at
term.
Since trophoblasts have the
capacity to detach and
reattach, many placentas
migrate away from the
internal os.
A full bladder can give a
false positive diagnosis of
placenta previa.
• (C.) Trophoblasts do not
have the capacity to detach
and reattach. So called
"migration" results from other
factors.
All of the following
statements are true
except…
Source: www.obgyn.ufl.edu
This image
demonstrates…
A.
B.
C.
D.
Placenta previa
A venous lake
An submembranous
blood clot from an
abruption
Amniotic band
syndrome
(C.) The appearance of this
hypoechoic area between the
membranes and uterine wall is
very suggestive of a blood clot.
Source: www.obgyn.ufl.edu
The membranes are separated
from the uterine wall. Amniotic
band syndrome should not be
diagnosed, however, unless
there is evidence of attachments
of the membrane to the fetus
associated with fetal anomalies
Amniotic Bands
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Multiple case reports of limb reduction/
deformities, facial clefts, and/or IUFD due
to umbilical cord entanglement
Case controlled study (n = 25 cases vs. 50
controls) showed…
Unrestricted fetal movement on all US
 No fetal abnormalities at birth
 Increased incidence of PTD
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Wehbeh H et al. The relationship between the ultrasonographic diagnosis of innocent amniotic band development and
pregnancy outcomes. Obstet Gynecol. 1993 Apr;81(4):565-8.
Which of the following
A)
is shown in this image?
B)
C)
D)
A placental abruption
A grade III placenta
Venous lakes
Placental infarcts
(D.) These hypoechoic
areas surrounded by
echogenic placenta are
characteristic of infarcts.
Infarcts frequently show
an echogenic rim and
absence of swirling blood
on Doppler flow.
Source: www.obgyn.ufl.edu
This area in the
placenta represents:
Source: www.obgyn.ufl.edu
A) A large venous lake
B) An abruption
C) An infarct
D) A chorioangioma
This hypoechoic area on the
surface of the placenta is
characteristic of a venous lake.
Blood flow can usually be seen with
real time imaging with the gain set
low.
Represent pooling of maternal
blood.
An infarct would be a hypoechoic
area within the placenta.
An abruption would show a
hypoechoic area below rather than
on the surface of the placenta.
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A rare placental tumor composed
of vascular spaces.
Usually seen as circumscribed
solid mass or complex mass that
protrudes from the fetal surface of
the placenta.
It has been postulated that these
tumors begin around the 16th17th day of development when a
newly formed angioblastic mass
becomes isolated from the rest of
the proliferating trophoblast
May cause…
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Cord compression
AV fistula  high output cardiac
failure in the fetus  hydrops
Turbulence  microangiopathic
anemia  hydrops
Polyhydramnios is present in one
third of the cases. Assoc with
PTD, IUFD and IUGR
Placental
Chorioangioma
Source: www.thefetus.net
These images show…
Source: www.emedicine.com
Source: Sharma et al, 2003
Clinical Significance of
Subchorionic “Collections”
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122 cases of SCC in 10 years at 1 institution detected
between 5-22 weeks, (no controls)
63% c/b bleeding
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Outcomes:
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88 % of those with PTD had bleeding
59 % of those del at term had bleeding
5 % SAB at 17-24 weeks
18 % PTD (median 35 wks)
77 % term delivery
Outcome not assoc. with maximal size, GA at detection
Sharma, et al. Prognostic factors associated with antenatal subchorionic echolucencies. Am J
Obstet Gynecol 2003;189: 994-6
Sharma, et al. Prognostic factors associated with antenatal subchorionic echolucencies. Am J
Obstet Gynecol 2003;189: 994-6
Significance of 1st trim SCC
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Matched case control study
238 cases and 648 controls
w/o VB
Cases comprised 1.3% of
total scanned population
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SAB: OR = 2.8
Stillbirth: OR = 4.5
Abruption: OR = 11.2
PTD: No difference
Ball, RH, et al. The clinical significance of ultrasonographically detected subchorionic hemorrhages (Am J Obstet
Gynecol 1996;174:996-1002.
Clinical Significance of 1st trim SCC
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Prospective study of
those with 1st
trimester hematoma
(n=230) vs. controls
(n=6488)
Outcomes similar
subchorionic vs.
retroplacental location
18.7% had loss at
less than 24 weeks
Relative Risk (all signif.)
 Preeclampsia 4.0
 Abruption
5.6
 Retained Plac 3.2
 IUGR
2.4
 Fetal distress 2.6
 Meconium
2.2
 NICU admit
5.6
 PTD
NS
Nagy et al. Clinical significance of subchorionic and retroplacental hematomas detected in the first trimester of pregnancy.
Obstet Gynecol. 2003 Jul;102(1):94-100
This image shows…..
A)
B)
C)
D)
A marginal abruption
A large venous lake
A placental hemangioma.
A retroplacental abruption
(D.) The hypoechoic area
represents a blood clot behind the
placenta.
A placental hemangioma would be
within the placenta, not behind the
placenta as this mass is.
This hypoechoic area underlies
the placenta.
Source: www.obgyn.ufl.edu
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Placental
abruption. This
retroplacental
hemorrhage is
visualized in a
patient during
the third
trimester of her
pregnancy.
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Source:
www.sunyabem.org/ultr
asound.shtml
US diagnosis of Placental
Abruption
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Nyberg et al.. Variety of
ultrasonographic appearances
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Glantz, et al… retrospective
cohort study
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Oyelese Y, Ananth CV. Placental abruption. Obstet
Gynecol. 2006 Oct;108(4):1005-16.
Acute phase: hyperechoic to
isoechoic
1 week: hypoechoic
2 weeks: sonolucent
Sensitivity 24%, specificity 96%, and
positive 88%, and negative
predictive values 53% of
ultrasonography for placental
abruption.
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B.
C.
D.
Placental abruption
Venous lakes
Partial mole
A degenerating fibroid
(C.) The "Swiss-cheese"
appearance of this placenta, with
the presence of a fetus (seen to the
right of the image) are
characteristic of partial mole.
A fibroid would have a more
rounded appearance. The cystic
spaces are within the placenta.
These cystic spaces are scattered
throughout the placenta.
The irregular cystic areas are within
the placenta itself, and don't have
the appearance of a retroplacental
blood clot
This image
shows:
Source: www.obgyn.ufl.edu
These images show…
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Color Doppler scan in
a 21-year-old woman
in 33rd week of
pregnancy (same
patient as in Image
12) demonstrates
prominent
retroplacental vessels
mimicking a
retroplacental
hematoma.
These images show…
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Sagittal endovaginal
scan of the uterus in a
29-year-old woman in
9th week of gestation
demonstrates
nonfusion and
separation of chorion
and amnion.
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Source:
www.emedicine.com/radio/t
opic662.htm
This image shows…
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6w3d, bleeding,
dichorionic twins
with one dead twin,
subchorionic
hemorrhage of
both chorions, the
living sac with a
larger hemorrhage
than the dead sac.
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Source:www.obgyn.net/.../us
/cotm/9904/cotm_9904
Back to the case….
A few more details…
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Per patient….
Previous delivery at 28 weeks (baby
weighed 1.5 lbs) after pt presented with
sudden vaginal bleeding and contractions
No bleeding yet in this pregnancy