TRONDHEIM National Center for Fetal Medicine Dept Ob & Gyn...

Fetal Imaging

TRONDHEIM

National Centerfor Fetal Medicine

Dept Ob & Gyn

Trondheim - Norway

Outline of presentation• Basic imaging technique• Normal sonoembryological and fetal development in 2D and 3D imaging

• The routine fetal examination at 18 weeks

• Fetal medicine

?Those were the days ..

Traditional obstetric communication with the fetus has changed

Sound• Infrasound (0 - 20 Hz)

• Audible sound (20 - 20kHz)

• Ultrasound > 20kHz• Diagnostic ultrasound (1 - 20 MHz)

Bats need ultrasound .....

Sound produced bybats is reflected fromthe walls of their cave.The echo patterns are picked up by the bat’s ears enabling them to avoid obstacles in the dark

Voltageimpulse

VoltageBurst

Ultrasoundpulse

Ultrasoundpulse

Sending

Receiving

Linear array

Weldner

1990

Technical developmentUltrasound imaging of the fetal head

19951970

1960

Fetal sections

Frontal section Sagittal section Horizontal section

The technical developmentwill go on -Smaller objects will be imaged betterend earlier

Embryology of Norwegians

At 9 weeks The Norwegian usually has mono-skis

A Norwegian at the routine 18 week scan

Fully developed Norwegian

What makes the embryospecial?Small size

5 weeks 10 weeks

2 610 13

2030 mm

Constantly changing of appearance

The implantation

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4 1/2 weeks

The sagital folding





6 weeks, CRL 4 mm

b

c

d

a b c

d

H

H

Rh

Rh MD

H H

Lennart Nilsson 7 weeks, CRL 12 mm

9 weeks, CRL 22 mm

The heart is relatively large compared to the body of the young embryo

0

5

10

15

20

25

30

0 10 20 30 40 50 60 70CRL

Hea

rt s

ize

%of

CR

L

CRL 6 mm

CRL 11 mm

CRL 29 mm

Size of embryonic/fetal heart

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10

0 10 20 30 40 50 60 70CRL (mm)

5

at 9 weeks2.6–4.8 mm

Blaas et al. 1995

+

++

+

Meandiameter(mm)

HeartTrondheim, 2001

61/2 weeks, CRL 6 mm

9 weeks; CRL 23 mm

Early diagnosis10 weeks

• Acrania, anencephaly, encephalocele• Myelomeningocele• Large facial defects• Limb defects; poly-, oligodactyly• Gross body wall defects (LBWC,

gastroschisis, epigastric omphalocele)• Major heart defects (AV-commune)

Fetus 13 weeks (CRL 65 mm)

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3D scan-conversion

Regular volumeUS data

For the evaluation of the small embryo by 3Dcertain demands have to be made to the ultrasound equipment

CRL 17 mm

Ultrasoundtomograms

d e

a b c

Embryonic development from 7 - 10 weeks(Blaas et al. The Lancet 1999)

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The shape

The evolution of aNorwegian -



Contours

Surface

Originalscan

CRL 29 mm9 weeks 6 days

Geometryvisualization

3D visualization modes

Volume

Segmentation

Anyplane slicing

3D - Still limited resolution

• Assessment of gestational age

• Location of the placenta• Detection of multiple

pregnancies• Detection of

developmental disorders

The fetal examination - 18 weeks

Invasiveprocedures

• Blood sampling• Blood transfusion• Acute drainage of fluid• Cronic drainage of fluid• Laser surgery

Fetal blood sampling



Fetal blood transfusions

• Direct intravascular• Umbilical vein, placental insertion• Infusion of packed cells, Hct ≥ 80%• Computer calculation of volume to be transfused• Infused volume up to 50% of fetoplacental

volume• Tranfusion velocity approx. 5 ml/min

Fetal blood transfusion



Conclusion

• Fetal blood transfusion forfetal Rh-disease has over 30years been developed toperfection using ultrasound

Drainage of fluid infetal / amniotic cavities

• Single or repeated aspirations• Application of pig-tail catheter

HydrothoraxPericardial fluidThoracic tumors (CCALM)Ovarian / mesenteric cyst(Urinary tract obstruction)

CCALM type I

Chylothorax

2 catheters inserted. 22 weeks

CCALM Type I

Chylothorax

35 weeks

Polyhydramnion

Slight upper body edema

Drainage of fetal chylothorax at 35 weeks

Needle tipAspiration of 115 mlcompleted

2000 challenge

Twin - twin transfusion

Laser ablation





The perinatal team

ObstetricianPediatriccardiologist Midwife

NeurosurgeonPathologist

PregnantcouplePediatrician Pediatric

surgeonNeonatologist

Geneticist Technician

The fetal examination

- some conditions where antenatal diagnosis may decide between life and death

• Sacrococcygeal teratoma• Cystic hygroma of the neck• Diaphragmatic hernia• Ductus dependent CHD• Abdominal wall defects• Cystic adenomatoid malformation of

the lung

Sacro coccygeal teratoma

Future obstetricsMaternal transport of afetus rather than a sick neonate

Epigastric omphaloceleabdominal wall

liverascites

umbilical cord

amnion

Wharton’s jelly

peritoneum

Gastroschisisabdominal wall

bowel

umbilical cord

Gastroschisis

Cystic hygroma

”EXIT”-procedure

EX utero Intrapartum

Treatment procedure

EXIT-procedure

So far - so good

Amniotic rupture sequence

Fetal medicine• Primarily take care of the fetal

condition, be a ”fetal doctor”• Act as the fetus’ advocate

but

• Have respect for the parents’choice

• Not ”sorting” of human beings

Fetal medicine•Will remain controversial

•Balance between obviously ”good”and ”bad”

The development of ultrasound

Based on cooperation between technician and clinician

Technician Clinician

Where are we going?

• Where new technology is taking us

• Where we are taking new technology

Åbødalen - my favorite mountains

TRONDHEIM National Center for Fetal Medicine Dept Ob & Gyn...

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