1. Presented by
Dr. Sandeep Garg (Resident)
Department of Radiodiagnosis
CMS
3rd Nov, 2011

2.  25 yrs female with 30 wks of POG and
uncontrolled hypertension was referred from
gynae/obsc dept for doppler.
 USG and doppler findings include
◦ >HC/AC ratio 1.32
◦ Severe oligohydraminos (AFI 3 cm)
◦ MCA PI 1.27
◦ UA PI 1.39
◦ MCA/UA PI ratio – 0.91
 Impression: fetal hypoxia/ IUGR

3.  IUGR: fetus with birth weight <10th
percentile for gestational age due to
pathologic process.
 SGA: fetus with birth weight <10th
percentile for gestational age in the
absence of pathologic process

4. Aetiology
Maternal Fetal Placental
Constitutional Cong anomalies Abn Trophoblast
Nutritional Chromosomal Velamentous cord
Genetic Infections Circumvallate p
Collagen vascular ds Multiple preg Pl Praevia
Autoimmune disease Pl infarction
HTN, Diabetes Tumors
Renal disease
Environmental

5.  Symmetrical : Uniformly small,
 HC:AC,FL:AC-Normal
 seen in chromosomal anomalies
 Asymmetrical : fetal abdomen is
disproportionately small
(Head sparing effect)
 HC>AC
 HC:AC, FL:AC-Elevated


6.  elevated HC/AC ratio (positive predictive
value 62%)
 elevated ratio of femur length to abdominal
circumference (FL/AC)
 presence of oligohydramnios without
ruptured membranes
 presence of advanced placental grade
(Grannum grade 3)

8.  Typically, scores of 6 or below are considered
frankly abnormal, and scores of 7 and 8 are
considered suspicious.
 Reduced biophysical profile scores are found
in growth restricted pregnancies that already
demonstrate abnormal umbilical and fetal
Doppler findings.

9.  Most of these fetuses are constitutionally
small, and are not suffering from
uteroplacental insufficiency.
 An inter-twin growth discrepancy of 20–25%
is considered to be significant.
 Twin-to-twin transfusion syndrome (TTTS)-
Color Doppler findings in the donor are
usually typical of uteroplacental insufficiency

10. Quantitative analysis
◦ Pulsatility index (PI)
◦ Resistance index (RI)
◦ Systolic/diastolic ratio
 Qualitative analysis
◦ Uterine artery: presence or
absence of early diastolic
notch
◦ UA : normal, with reduced
diastolic flow, absent EDF,
reversed EDF

11.  Uterine arteries branch into arcuate arteries, leading
to spiral arteries within myometrium.
 With advancing pregnancy, due to trophoblastic
invasion of uterine spiral arteries, it dilates and result
in fall in resistance to blood flow.
 Uterine blood flow in non pregnant women is 50
ml/min and increase to over 700 ml/min in 3rd
trimester.
 Hence, in normal pregnancy diastolic component is
transformed from one of low peak flow velocity and
early diastolic notch , to one of high flow and no
diastolic notch by 18 to 22 wks, PI value <1.2
 PI >1.45 with bilateral notches (abnormal) is s/o
clinically significant uteroplacental vascular
ischaemia.

17.  Characteristic umbilical artery waveforms
have also been correlated to various degrees
of fetal hypoxemia and acidemia.
 Absent end-diastolic frequencies
◦ 75% of the placental vascular bed has been
obliterated
◦ 85% chance that the fetus will be hypoxemic and
a 50% chance that it will also be acidemic.
 Reversed end-diastolic frequencies
◦ ten-fold increase in perinatal mortality

21.  Fetal arterial waveforms are acquired from the
thoracic aorta and middle cerebral arteries.
 With fetal hypoxemia, there is conservation (or
increase) of blood flow to the fetal brain, heart
and adrenal glands with concomitant decrease in
flow to the splanchnic bed and extremities. This
phenomenon is termed ‘arterial redistribution of
blood flow’, and serves to deliver oxygen and
nutrients to vital organs in the face of impaired
placental function.
 Hence, fetal arterial Dopplers can be used to
monitor fetal compensatory responses to
progressively deteriorating placental function.

22.  MCA can be easily demonstrated by color
doppler in transverese fetal head position.
 At 28-32 wks, MCA is characterized by high
systolic velocities and minimal diastolic
velocities, resulting in high PI values (>1.45).
 In fetal hypoxia, vascular tone is increased in
MCA resulting in increased diastolic velocity
and reduced PI values.

24. Normal
With hypoxia there is cerebral
vasodilatation, so initially the
diastolic flow may be in the
normal range ,when the
vasodilatation ability is
exhausted as with fetal
acidosis the resistance starts
increasing again.

27.  A longitudinal view of
the fetal thoracic aorta
is obtained with color
flow imaging.
 The pulsed Doppler
sample gate should be
placed on the linear
portion of the
descending thoracic
aorta, above the level
of the diaphragm

28.  The ductus venosus is the main vessel through
which oxygenated blood returning from the
placenta is directed to the fetal heart and
circulation.
 With worsening fetal hypoxemia, abnormal
umbilical artery waveforms and severe fetal
arterial redistribution develop.
 In addition, there is also increased redistribution
of highly oxygenated umbilical vein blood
through the ductus venosus to the fetal heart.
 When the fetal condition becomes critical,
abnormal ductus venosus flow waveforms are
seen.

30. Normal Abnormal

31.  Biometry
◦ EFW 640 g (<10th centile)
◦ HC/AC ratio 1.35 (normal <1.2)
◦ AFI 7 cm (normal 10-20 cm)
 Doppler
◦ Uterine arteries- B/L early diastolic notch
◦ Lt uterine artery PI 1.97, Rt PI 1.65
◦ UA- absent EDF in both
◦ Smooth umbilical venous cord flow, peak vel 16cm/sec
◦ MCA- PI 1.12 (redistribution)
◦ Ductus venosus – positive A wave 32 cm/sec (normal)
 Biophysical profile score- 8/8 normal
 Anatomic evaluation- short femurs, mildly
echogenic bowel

32.  Gramellini et al (1992) studied that in 30-41
wks POG, MCA/UA PI ratio (cerebro-umbilical
flow) <1.08 is better predictor of fetal
insufficiency than MCA PI or UA PI alone.
Diagnostic accuracy for the cerebral-
umbilical ratio was 90%, compared with 78.8%
for the middle cerebral artery and 83.3% for
the umbilical artery.

34.  1990 G.Mari proposed the use of MCA
dopplers for the diagnosis of anemia
 The sensitivity of the peak systolic velocity for the
prediction of moderate anemia and severe anemia
in the fetuses without hydrops was 100 percent ,
with a false positive rate of 12 percent. The
positive and negative predictive values were 65
percent and 100 percent, respectively.

35.  The risk of anemia was high in fetuses with a
peak systolic velocity of 1.50 times the
median or higher. Fetuses with values below
1.50 either did not have anemia or had only
mild anemia.

37.  the MCA PSV is effective for accurate
diagnosis of fetal anemia and can avoid about
70% of invasive procedures.