Title: Placental US
1Placental US
2Case of the Day
- 18 yo G2 P0101 at 18 weeks by 1st trimester sono
presented for an anatomy ultrasound - Size dates
- Fetus anatomically normal male
- Posterior placenta
3(No Transcript)
4(No Transcript)
5(No Transcript)
6Outline
- Various placental ultrasound findings
- Changes with gestational age
- Echolucencies
- Others..
7This image shows
- 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.
Source www.obgyn.ufl.edu
8- 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
Source Google images
9These images show
- 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
10Normal Placental appearance
- 8-20 weeks uniform echotexture, 2-3 cm thickness
- gt20 weeks
- Measures 4-5 cm thick
11- 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
12- Grade 0
- Late 1st trimester-early 2nd trimester
- Uniform moderate echogenicity
- Smooth chorionic plate without indentations
13- Grade 1
- Mid 2nd trimester early 3rd trimester (18-29
wks) - Subtle indentations of chorionic plate
- Small, diffuse calcifications (hyperechoic)
randomly dispersed in placenta
14- Grade 2
- Late 3rd trimester (30 wks to delivery)
- Larger indentations along chorionic plate
- Larger calcifications in a dot-dash
configuration along the basilar plate
15- Grade 3
- 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
16Significance of Placental Grade
- N 1802 low-risk patients at 36 weeks
- Grade III placenta found in 3.8 (68/1802).
- Associated with young maternal age and cigarette
smoking, p lt 0.01. - PIH Study group 7.4 (5/68) and 1.56 of
controls (27/1734), p lt 0.01. - SGA 17.6 (12/68) vs. 5.6 (97/1734), p lt 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 Jan84(1)7-10.
17This 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
18All of the following statements are true except
- 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.
Source www.obgyn.ufl.edu
19This image demonstrates
- 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. 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
Source www.obgyn.ufl.edu
20Amniotic Bands
- 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
Wehbeh H et al. The relationship between the
ultrasonographic diagnosis of innocent amniotic
band development and pregnancy outcomes. Obstet
Gynecol. 1993 Apr81(4)565-8.
21Which of the following is shown in this image?
- 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
22This area in the placenta represents
- A) A large venous lakeB) An abruptionC) An
infarctD) 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.
Source www.obgyn.ufl.edu
23Placental Chorioangioma
- 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 16th-17th day of development when a
newly formed angioblastic mass becomes isolated
from the rest of the proliferating trophoblast - May cause
- 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
Source www.thefetus.net
24These images show
Source Sharma et al, 2003
Source www.emedicine.com
25Clinical Significance of Subchorionic
Collections
- 122 cases of SCC in 10 years at 1 institution
detected between 5-22 weeks, (no controls) - 63 c/b bleeding
- 88 of those with PTD had bleeding
- 59 of those del at term had bleeding
- Outcomes
- 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 2003189 994-6
26Sharma, et al. Prognostic factors associated with
antenatal subchorionic echolucencies. Am J Obstet
Gynecol 2003189 994-6
27Significance of 1st trim SCC
- Matched case control study 238 cases and 648
controls w/o VB - Cases comprised 1.3 of total scanned population
- 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
1996174996-1002.
28Clinical Significance of 1st trim SCC
- Prospective study of those with 1st trimester
hematoma (n230) vs. controls (n6488) - 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 Jul102(1)94-100
29This image shows..
- 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
30- Placental abruption. This retroplacental
hemorrhage is visualized in a patient during the
third trimester of her pregnancy. - Source www.sunyabem.org/ultrasound.shtml
31US diagnosis of Placental Abruption
- Nyberg et al.. Variety of ultrasonographic
appearances - Acute phase hyperechoic to isoechoic
- 1 week hypoechoic
- 2 weeks sonolucent
- Glantz, et al retrospective cohort study
- Sensitivity 24, specificity 96, and positive
88, and negative predictive values 53 of
ultrasonography for placental abruption.
Oyelese Y, Ananth CV. Placental abruption. Obstet
Gynecol. 2006 Oct108(4)1005-16.
32(No Transcript)
33This image shows
- 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
Source www.obgyn.ufl.edu
34These images show
- 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.
35These images show
- 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. - Source www.emedicine.com/radio/topic662.htm
36This image shows
- 6w3d, bleeding, dichorionic twins with one dead
twin, subchorionic hemorrhage of both chorions,
the living sac with a larger hemorrhage than the
dead sac. - Sourcewww.obgyn.net/.../us/cotm/9904/cotm_9904
37Back to the case.
38(No Transcript)
39(No Transcript)
40A few more details
- 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