7/6/2015

Obstetric Ultrasound 2nd/3rd
Trimesters
Mary C. Frates, MD, FACR
Fetal Lie (Vtx vs Breech)
–Self explanatory
Cervix/Cord/Placenta/Fluid
 Measurements (Biometry)
 Survey/ BPP
 ACR/AIUM/ACOG/SRU
guidelines for Obstetric US

Cervix - TA
Cervix






Normal > 3 cm, closed
Shortened and closed (effaced)
Dilated internal os (funneled)
May be dynamic
May need TVS
Rx: cerclage/pessary/bedrest
Cervical length changes
with pressure/ bladder distention
Daska long cervix full bladder.jpg
Karinskas- normal TA cervix
Normal TV
Open
Normal
Normal
Ambrosino TV cervix looks normal 31 wks.jpg
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Umbilical Cord

3 VC
2
Stevens 27w dilated entire Cx canal and open
external os 11 mm.jpg Simmon feet in canal 18

arteries and one vein
2 VC

one artery and one vein (same size)
 increased risk anomalies/IUGR
Open

Vellamentous Cord
Inserts
into the membranes
Funic
Presentation
normal 3VC color.jpgPamphile 2 VC color.jpg
Broderick funic presentation ruptured membs Cord
presenting tranverse lie
2 VC
3 VC
Vellamentous CI
Placenta



Location re: cervix
Location re: uterine wall
Staging- no real value

Verdieu vellamentous CI

decisions based on fetal status
Masses
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7/6/2015
Placenta Previa*
Placenta Previa
Relationship of placenta to
internal os
 Established AFTER 16 weeks
 No previa (over 2 cm away)
 Low Lying (within 2 cm)
 Previa – overlying internal os

1/200
births
*NIH Executive Summary on Fetal Imaging; Ob Gyn2014; 123:1070
Placenta Previa
Placenta previa 27 wks Placenta Marginal previa
TV.jpgAnger.jpg
Previa
If low lying or previa is found: followup at 32 weeks
 If still low lying or previa: follow-up at
36 wks
 Consider TVS with color to exclude
vessels over the os

Vasa Previa
Ho vellamentous cord splits between ant and post
placs
Low-lying
Vasa Previa
Placenta Acreta

Ho vellamentous cord splits between ant and post
placs
Abnormal placental attachment
Typically

at a scar
Acreta-Increta-Percreta
Myometrial
depth
Increased risk after C-section
 Increased risk with venous
lakes, anterior previas

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7/6/2015
Placenta Percreta
Placenta Acreta Lateral
Watson placenta acreta 22 wks
Dinino lateral percreta 30wks.jpg
22 wks
30 wks
Placenta Cyst
Mass
Placenta Cysts vs Tumors
typically simple
fetal surface
 near cord
insertion
 if large,
associated
with IUGR
chorioangioma
solid
 anywhere
 typically benign
 if large, vascular
shunting and fetal
hydrops




Abramson placental cysts IUGRLeitner
chorioangioma
31 wks
Amniotic Fluid

Oligohydramnios
Mild-moderate-severe

Polyhydramnios
Brumfield absent kidneys bladder severe oligo
TRV.jpg
Mild-moderate-severe

Subjective vs AFI
4

Quadrant measurements
Oligohydramnios
Look for an explanation
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7/6/2015
Measurements (Biometry)
Know the rules!
Baker severe poly trach atresia w fist
 Head


Head Measurements: BPD
Measurements

Follow the rules!
symmetrically positioned 3rd ventricle/
thalami
 falx down the middle, CSP anteriorly
correct plane and correct endpoints

 small error pre-viable is not clinically

largest possible, along skull base

 optimize the image

Abdomen
Femur
significant
error more important at extremes

calvaria smooth and symmetric
cursers:

– recognize the large scale errors

outer to inner
leading edge to leading edge
Mistakes
Abdomen Diameter Measurements
level of liver (largest intra-abdominal
organ in fetus)
 stomach and intrahepatic umbilical vein
Junction of left and right portal vein
 skin edge to skin edge

Bennett bad head orbits included.jpg
Correct
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7/6/2015
Abdominal Measurements
Mistake
When struggling Round is best
berrios 30wks bad ADmeasurements prone.jpg
Keep AD measurements within 10
mm of each other
 This gives a pretty good estimate
even without other landmarks

Fetus is pronelandmarks obscured by spine
Correct
Measurements: Femur
long axis of the bone (ossified
portion) parallel to transducer
 epiphysis is excluded
 measure at junction of cartilage and
bone

berrios 30wks bad ADmeasurements prone.jpg
NOT the longest echogenic point (the “distal
femoral point”) which has no anatomic
correlate)

Correct
Mistake
Mistake
Femur measurement 35wks depth too high.jpg MacDougall good
measurements
all of abdominal
wall is not included
Bad AC measurement 1.jpg
EFW
BW
Image too tiny to see landmarks
3971 gms
4850 gms
Vaginal delivery c/b shoulder dystocia
Severe hypoxemia; baby died DOL 2 hypoxemia and acidosis
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7/6/2015
2/3 trimester: Anatomy
Measurements (Biometry)


>90 % macrosomic
> 4500 gms –C section (9,15)
 > 4000 gms in diabetic (8,14)

< 10% IUGR






80% small/20% sick
 only < 5% are really IUGR


Normal/ normal variants
Chiari Malformation




Lemon/Banana
Hydrocephalus
Hydranancephaly
Holoprosencephaly
Lateral Ventricle
GI/GU
Abdominal wall
Cerebral Ventricles
Head

CNS
Heart
Thorax
Abdomen

plane must be level
Off
axis measurement will increase
size
 always use the smallest technically
accurate measurement
 all errors result in larger size ventricle
Choroid Plexus
Cysts
Collins CP cyst 19wks.
brea hydroecphalus.jpgAli borderline ventricle but
dangling choroid 18w.jpg
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7/6/2015
Chiari Malformation



Lemon/ Banana
Spine defect
** Need Sagittal Image
Cardoso LS meningocele 18 wks PF.jpgbad measurement down.jpg
Fluid in the Brain
Holopros Hydranen Hydroceph
Smith lumbar meningomyelocele Trv.avi
Falx
Cortex
No
Yes
Yes
Yes
No
Yes
Hydranencephaly
Holoprosencephaly
Avignon holopros
Falx No
Cortex Yes
Sutton hydranencephaly first survey 31wks.jpg
Falx Yes
Cortex No
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7/6/2015
Hydrocephalus
Heart
4 chamber
Aorta and Pulmonary Outflow
Tracts
 3 Vessel View
 Clips are mandatory
 Color?


Kosinski severe hydrocephalus, prob aqued stenosis.jpg
Falx Yes
Cortex Yes
lazard nml heart 4 Ch 35w.jpg
Normal 4 ch; nml Ao L
side down Wilson; nml PA
wilson
Cine clip is critical
Poynton hypoplastic LV
20 wks
Ortiz vsd only seen on clip
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7/6/2015
Heart
 4 Chamber only is not enough
Bouchartd AV canal Tris
21
Technique critical with Ao and PA
 Ao must be imaged in axial plane,
with RV and septum on image

Lesser Tet nml 4 chamber
Ewing TGA 33
Thorax
3 vessel view Normal Guzman dillon TGA 3
vessel view missing one. Arevalo abnml 3VV
TGA
 Diaphragmatic hernia


CPAM/ sequestration
Tracheal/bronchial atresia
3VV
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7/6/2015
CPAM
Conley huge CCAM fills entire R chest 21wks.avi
Amiri L CDH chest
CDH
Tracheal Atresia
Abdomen/ Kidneys
17 weeks
 Caliectasis/hydronephrosis
Posterior urethral valves
Multicystic dysplastic kidney
 Autosomal recessive polycystic
kidneys

Nastanski tracheal atresia

 Often
Hydronephrosis
affects fluid ()
Posterior Urethral Valves
Reilly PUVs keyhole and ascites.jpg
Davis R UVJ 36 w , Silva hydronephrosis
hydroureter 38wks.avi
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7/6/2015
Multicystic Dysplastic Kidney
ARPCK
oligo
Vaughn MCDK sag 28wk.avi
Deming ARPCK 3.JPG Wentworth ARPCK
Duodenal Atresia
Abdomen/ GI

Stomach
Dilated bowel loops
Perforation/ Meconium Ileus

Often affects fluid ()


Paige 18.5 wks missing LK called normal.
Trisomy 21
Small Bowel Obstruction
Meconium Peritonitis/ SBO
More Distal
Louis prox jejunal obstruction 32w.aviSharma SBO 37wks.avinormal.
Garabedian high SBO and mec peritonitis.jpg.
Proximal
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7/6/2015
Gastroschisis
Abdominal Wall

Gastroschisis

free floating loops of bowel
 defect to the right of CI
 ascites impossible

Welch gastroschisis Vaughn gastrischisis 31w.avi
Omphalocele

membrane covered protrusion
 Cord inserts into mass
 ascites possible
Omphalocele
No membrane
Normal CI
Douglas cleft lip
and TGA
Pamphile omphal Trv.jpg Joyce omphalocele no liver.avi
Douglas cleft lip nml coronal.jpg
+ Membrane
CI into mass
Brea bilat club feet extra piece chrom 14.avi.
gregson 4gXX nml hand Suarez postaxial polydactyly 17wks mom has it.
Diallo clenched hands Tris 18
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7/6/2015
Nuchal cord
Nucahl cord (Kosar)
BPP:
2
2
2
2
AVF
Movement
Tone Valdez 8-8 BPP extremity movement.avi
Breathing
And….
2/3 Trimester
Measurements
Survey
 Some abnormalities develop
over time
 Don’t call something
unevaluable without considering
it might be abnormal

Sayag sticking tongue out 30 wks3D yawning fetus

14