ob-dopplerultrasound

8/7/2019 OB-dopplerultrasound

1/36

DOPPLER ULTRASOUNDDOPPLER ULTRASOUND

in Pregnancyin Pregnancy

Dr. Mohammed AbdallaDr. Mohammed Abdalla

Egypt, Domiat HospitalEgypt, Domiat Hospital


2/36

First use of DopplerFirst use of Doppler

ultrasonography to studyultrasonography to study

flow velocity in the fetalflow velocity in the fetal

umbilical arteryumbilical arterywas reported inwas reported in 19771977

Doppler HistoryDoppler History


3/36

Doppler HistoryDoppler History

Fitzgerald & Drumm.Fitzgerald & Drumm. Umbilical artery studiesUmbilical artery studies 19771977BMJBMJ

EikEik--Nes et al.Nes et al. Fetal aortic velocimetryFetal aortic velocimetry : Dupplexscanner: Dupplexscanner

19801980 LancetLancet

Campbell et al.Campbell et al. UteroUtero--placental circulationplacental circulation: Dupplex: Dupplexscanner 1983scanner 1983 LancetLancet

Wladimiroff et al.Wladimiroff et al. MCA / UA PI ratioMCA / UA PI ratio 19871987 OGOG

Kiserud et al.Kiserud et al. Ductus venosus velocimetryDuctus venosus velocimetry 19911991LancetLancet


4/36

Basic principalsBasic principals

Echoes from stationary tissues are the same fromEchoes from stationary tissues are the same frompulse to pulse.pulse to pulse.

Echoes from moving objects exhibit slightEchoes from moving objects exhibit slight

differences in the time for the signal to bedifferences in the time for the signal to bereturned to the receiver.returned to the receiver.

These differences can measured asThese differences can measured asphase shiftphase shiftfrom which thefrom which the Doppler frequencyDoppler frequencyis obtained.is obtained.


5/36

TT11 : time of omitted signal: time of omitted signal ..

TT22 : time of returned signal .: time of returned signal .

TT22 TT11 == time difference or phasetime difference or phase

shift .shift .

from phase shift the Dopplerfrom phase shift the Doppler

frequency is obtained.frequency is obtained.

AS TIME DIFFERENCE DECREASE THEAS TIME DIFFERENCE DECREASE THEDOPPLER FREQUENCY INCREASE.DOPPLER FREQUENCY INCREASE.


6/36

pulse repetition frequencypulse repetition frequency

(T2 T1)phase shiftphase shiftwith known beam / flow angle cancalculate flow velocity .

T1

T2


7/36

The time difference or phase shiftThe time difference or phase shift

are then proceeded to produceare then proceeded to produce

eithereithercolorflow displaycolorflow display or aor a

Doppler sonogramDoppler sonogram

Basic PrincipalsBasic Principals


8/36


Doppler frequency is obtained by measuringDoppler frequency is obtained by measuring

the time difference for the signal to be returnedthe time difference for the signal to be returned

when reflected from moving scatterers .when reflected from moving scatterers .

Doppler frequency increase if:Doppler frequency increase if:

1.1. flow velocity increased .flow velocity increased .

2.2. beam is more aligned to the direction ofbeam is more aligned to the direction of

flow.flow.

3.3. higher transducer frequency is used.higher transducer frequency is used.


9/36

(the angle(the angle qq between the beam and the direction ofbetween the beam and the direction of

flow becomes smaller). This is of the utmostflow becomes smaller). This is of the utmost

importance in the use of Doppler ultrasound.importance in the use of Doppler ultrasound.

qq

The angle of insonation

Flow velocity

3

2

1

Factors affecting doppler frequency


10/36

(the angle(the angle qq between the beam and the direction of flowbetween the beam and the direction of flow

becomes smaller). This is of the utmost importance in thebecomes smaller). This is of the utmost importance in the

use of Doppler ultrasound.use of Doppler ultrasound.

beambeam (A)(A) is more aligned thanis more aligned than (B)(B)

The beam/flow angle atThe beam/flow angle at (C)(C) is almostis almost 9090 and there is a very poor Doppler signaland there is a very poor Doppler signal

The flow atThe flow at (D)(D) is away from the beam and there is a negative signal.is away from the beam and there is a negative signal.


11/36

AliasingAliasing

If a second pulse is sent before the first is received, the receiver cannot

discriminate between the reflected signal from both pulses and aliasing

occur.


12/36

So to eliminate aliasing TheSo to eliminate aliasing The

pulse repetition frequency orpulse repetition frequency or

scale is set appropriately forscale is set appropriately for

the flow velocitiesthe flow velocities

AliasingAliasing


13/36

The volume flow in the UAsThe volume flow in the UAs

increases with advancingincreases with advancing

gestation. The high vasculargestation. The high vascularimpedance detected in the firstimpedance detected in the first

trimester gradually decreases. It istrimester gradually decreases. It is

attributed to growth of placentalattributed to growth of placental

unit and increase in the number ofunit and increase in the number ofthe functioning vascular channels.the functioning vascular channels.



14/36

UsesUsesplays a vital role in the diagnosis ofplays a vital role in the diagnosis of

fetalfetal cardiac defectscardiac defects ..

assessment of the hemodynamicassessment of the hemodynamicresponses to fetalresponses to fetal hypoxiahypoxia andand

anemiaanemia..

diagnosis of otherdiagnosis of other nonnon--cardiaccardiacmalformations.malformations.


15/36

Blood supply provided byBlood supply provided bythe ovarian and uterinethe ovarian and uterine

arteriesarteries

Uterine Arteries: mainUterine Arteries: main

branches of the internalbranches of the internaliliac arteriesiliac arteries

Uterine Arteries: AscendUterine Arteries: Ascend

through the lateral wall andthrough the lateral wall and

anastomose with theanastomose with the

ovarian arteriesovarian arteries

Blood supply provided byBlood supply provided bythe ovarian and uterinethe ovarian and uterine

arteriesarteries

Uterine Arteries: mainUterine Arteries: main

branches of the internalbranches of the internaliliac arteriesiliac arteries

Uterine Arteries: AscendUterine Arteries: Ascend

through the lateral wall andthrough the lateral wall and

anastomose with theanastomose with the

ovarian arteriesovarian arteries

AnatomyAnatomyAnatomyAnatomy


16/36

Spiral Arteries: connect the maternal circulation to theSpiral Arteries: connect the maternal circulation to the

endometriumendometrium

Responsible for a 10 fold increase in blood flowResponsible for a 10 fold increase in blood flow

Spiral Arteries: connect the maternal circulation to theSpiral Arteries: connect the maternal circulation to the

endometriumendometrium

Responsible for a 10 fold increase in blood flowResponsible for a 10 fold increase in blood flow


Arcuate Arteries: Run Circumferentially around the uterusArcuate Arteries: Run Circumferentially around the uterus Uterus: Blood supply to anterior and posterior wallsUterus: Blood supply to anterior and posterior walls

provided by the Arcuate arteriesprovided by the Arcuate arteries

Radial Arteries: Extend from the arcuate arteries andRadial Arteries: Extend from the arcuate arteries and

enter the endometriumenter the endometrium

Arcuate Arteries: Run Circumferentially around the uterusArcuate Arteries: Run Circumferentially around the uterus Uterus: Blood supply to anterior and posterior wallsUterus: Blood supply to anterior and posterior walls

provided by the Arcuate arteriesprovided by the Arcuate arteries

Radial Arteries: Extend from the arcuate arteries andRadial Arteries: Extend from the arcuate arteries and

enter the endometriumenter the endometrium


17/36

Conversion of small muscular spiral arteries into largeConversion of small muscular spiral arteries into large

vascular channels transforms the uteroplacentalvascular channels transforms the uteroplacental

circulation into a lowcirculation into a low--resistanceresistance--toto--flow system. Theseflow system. Thesehave a dilated and tortuous lumen, a complete absencehave a dilated and tortuous lumen, a complete absence

of muscular and elastic tissue, no continuousof muscular and elastic tissue, no continuous

endothelial lining.endothelial lining.

Conversion of small muscular spiral arteries into largeConversion of small muscular spiral arteries into large

vascular channels transforms the uteroplacentalvascular channels transforms the uteroplacental

circulation into a lowcirculation into a low--resistanceresistance--toto--flow system. Theseflow system. Thesehave a dilated and tortuous lumen, a complete absencehave a dilated and tortuous lumen, a complete absence

of muscular and elastic tissue, no continuousof muscular and elastic tissue, no continuous

endothelial lining.endothelial lining.



18/36

Umbilical artery

doppler


19/36

Doppler indices


20/36

UMBILICAL ARTERY FLOW

characteristic saw-tooth appearance of arterial

flow in one direction and continuous umbilical

venous blood flow in the other.

Umbilical arteryUmbilical artery


21/36

FACTORS AFFECTING UMBILICAL ARTERY DOPPLERFACTORS AFFECTING UMBILICAL ARTERY DOPPLER

FLOW VELOCITY WAVEFORMS*FLOW VELOCITY WAVEFORMS*


22/36

Benefit of Umbilical Artery EvaluationBenefit of Umbilical Artery Evaluation

Less experienced operators can achieveLess experienced operators can achieve

highly reproducible results with simple,highly reproducible results with simple,inexpensive continuousinexpensive continuous--wavewave

equipment .equipment .



23/36

The 40% of the combined fetal ventricular output isThe 40% of the combined fetal ventricular output is

directed to the placenta by two umbilical arteries.directed to the placenta by two umbilical arteries.The assessment of umbilical blood flow providesThe assessment of umbilical blood flow provides

information on blood perfusion of the fetoplacentalinformation on blood perfusion of the fetoplacental

unit .unit .



24/36

With advancing gestation,With advancing gestation,

umbilical arterial Dopplerumbilical arterial Doppler

waveforms demonstrate awaveforms demonstrate a

progressive rise in theprogressive rise in the

endend--diastolic velocity anddiastolic velocity and

a decrease in thea decrease in the

pulsatility index.pulsatility index.



25/36

Middle cerebral artery

doppler


26/36

Using color flow imaging, the middle cerebral artery can be

seen as a major lateral branch of the circle of Willis, running

anterolaterally at the borderline between the anterior and the

middle cerebral fossae

The possible Doppler velocimetry sitesThe possible Doppler velocimetry sites

Middle cerebral artery


27/36

Middle cerebral arteryMiddle cerebral artery

The blood velocity increases with advancing gestation,

and this increase is significantly associated with the

decrease in PI


28/36

An early stage in fetal adaptationAn early stage in fetal adaptation toto hypoxemiahypoxemia --central redistribution of blood flowcentral redistribution of blood flow

( brain( brain--sparing reflex)sparing reflex)

increased blood flow to protect the brain, heart,increased blood flow to protect the brain, heart,and adrenalsand adrenals

reduced flow to the peripheral and placentalreduced flow to the peripheral and placentalcirculationscirculations

Middle cerebral arteryMiddle cerebral artery


29/36

Doppler wave form of early stage ofDoppler wave form of early stage of

fetal hypoxemiafetal hypoxemia

increased endincreased end--diastolic flow in the middlediastolic flow in the middle

cerebral artery (lower MCAcerebral artery (lower MCA pulsatilitypulsatility

indexindex or resistanceor resistance indexindex))

Average of both MCAs must be calculatedAverage of both MCAs must be calculated

for more precise resultfor more precise result


30/36

Middle Cerebral ArteryMiddle Cerebral Artery

Flow velocity waveform in the fetal middle cerebral arteryFlow velocity waveform in the fetal middle cerebral arteryin a severely anemic fetus atin a severely anemic fetus at 2222 weeks (left) and in aweeks (left) and in anormal fetus (right). In fetal anemia, blood velocity isnormal fetus (right). In fetal anemia, blood velocity isincreasedincreased


31/36

When the fetus is hypoxic, the cerebra arteriesWhen the fetus is hypoxic, the cerebra arteries

tend to become dilated in order to preservetend to become dilated in order to preserve

the blood flow to the brain and The systolic tothe blood flow to the brain and The systolic to

diastolic (A/B) ratio will decrease (due to andiastolic (A/B) ratio will decrease (due to an

increase in diastolic flow)increase in diastolic flow)

Middle Cerebral ArteryMiddle Cerebral Artery


32/36

Doppler ultrasound for the fetal assessment inDoppler ultrasound for the fetal assessment in

highhigh--risk pregnanciesrisk pregnancies

(Cochrane Review). In:(Cochrane Review). In: The Cochrane Library,The Cochrane Library,

19991999. Neilson JP and Alfirevic Z. Neilson JP and Alfirevic Z

Trudinger et alTrudinger et al 19871987

McParland et alMcParland et al 19881988

Tyrrell et alTyrrell et al 19901990 Hofmeyr et alHofmeyr et al 19911991

Newham et alNewham et al 19911991

Burke et alBurke et al 19921992

11 Studies Included In Analysis

Almstrom et al 1992

Biljan et al 1992

Johnstone et al 1993Pattison et al 1994

Nienhuis et al 1997


33/36

Doppler ultrasound for the fetal assessmentDoppler ultrasound for the fetal assessment

in highin high--risk pregnanciesrisk pregnancies

NearlyNearly 70007000 patients were includedpatients were included

The trials compared no Doppler ultrasound toThe trials compared no Doppler ultrasound to

Doppler ultrasound in highDoppler ultrasound in high--risk pregnancyrisk pregnancy

(hypertension or presumed impaired fetal(hypertension or presumed impaired fetal

growth)growth)

Meta analysis


34/36

Doppler ultrasound for the fetal assessmentDoppler ultrasound for the fetal assessment

in highin high--risk pregnanciesrisk pregnancies

A reduction in perinatal deaths.A reduction in perinatal deaths.

Fewer inductions of labour .Fewer inductions of labour .Fewer admissions to hospital .Fewer admissions to hospital .

no report of adverse effects .no report of adverse effects .

No difference was found for fetal distressNo difference was found for fetal distressin labour .in labour .

No difference in caesarean delivery .No difference in caesarean delivery .

Main results


35/36

Biophysical profile for fetal assessment inBiophysical profile for fetal assessment in

high risk pregnancieshigh risk pregnancies

When compared with conventional fetal monitoring When compared with conventional fetal monitoring

(usually cardiotocography) biophysical profile(usually cardiotocography) biophysical profiletesting showed no obvious effect (either beneficialtesting showed no obvious effect (either beneficial

or deleterious) on pregnancy outcome. There wasor deleterious) on pregnancy outcome. There was

an increase in the number of inductions of labouran increase in the number of inductions of labour

following biophysical profile in the trial.following biophysical profile in the trial.

Alfirevic Z, Neilson JP. Biophysical profile for fetal assessment in high risk

pregnancies (CochraneReview). In: The Cochrane Library, 1995.


36/36

ob-dopplerultrasound

Documents