2D, 3D, 4D OBSTETRICAL USG FOR FETAL WELL BEING, ANOMALY SCANE, TVS FOR EARLY PREGNANCY, COLOUR DOPPLER STUDY ......

1. Obstetrical Ultrasound
DR. YOGESH PATEL
MBBS, DGO
PG DIPLOMA IN ULTRASONOGRAPHY (D. USG)
FELLOWSHIP IN INFERTILITY (F. ART)
DIPLOMA IN LAPAROSCOPY (D. MAS)
FELLOWSHIP IN LAPAROSCOPY (F. MAS)
EMERGENCY MEDICINE SPECIALIST
FORMER CONSULTANT AIIMS NEW DELHI
MEMBER OF THE WORLD ASSOCIATION OF LAPROSCOPIC
SURGEONS

2. Ultrasound in Ultrasonography
• In physics, the term "ultrasound" applies to
all acoustic energy (longitudinal,
mechanical wave) with a frequency above
the audible range of human hearing. The
audible range of sound is 20 hertz-20
kilohertz. Ultrasound is frequency greater
than 20 kilohertz.

3. Ultrasound Technology
• Principle of SONAR, used by bats and ships
• Generation of high-frequency sound waves
through a transducer
• Pulsed sound waves penetrate till structures
of different tissues densities is reached
• Reflected energy to the transducer is
amplified and displayed on a screen
• Detection of breathing, cardiac actions and
vessel pulsations

4. Obstetrical Ultrasound
• Introduced in the late 1950’s
ultrasonography is a safe, non-
invasive, accurate and cost-effective
means to investigate the fetus
• Computer generated system that uses
sound waves integrated through real
time scanners placed in contact with a
gel medium to the maternal abdomen
• The information from different
reflections are reconstructed to
provide a continuous picture of the
moving fetus on the monitor screen

5. Risks and Side-effects
• Ultrasonography is generally considered a "safe" imaging
modality. However slight detrimental effects have been
occasionally observed (see below). Diagnostic ultrasound
studies of the fetus are generally considered to be safe
during pregnancy. This diagnostic procedure should be
performed only when there is a valid medical indication,
and the lowest possible ultrasonic exposure setting should
be used to gain the necessary diagnostic information under
the "as low as reasonably achievable" or ALARA
principle.

6. • World Health Organizations technical report series
875(1998).supports that ultrasound is harmless:
"Diagnostic ultrasound is recognized as a safe, effective,
and highly flexible imaging modality capable of providing
clinically relevant information about most parts of the
body in a rapid and cost-effective fashion". Although there
is no evidence ultrasound could be harmful for the fetus,
US Food and Drug Administration views promotion,
selling, or leasing of ultrasound equipment for making
"keepsake fetal videos" to be an unapproved use of a
medical device.

7. • Studies on the safety of ultrasound
A study at the Yale School of Medicine found a correlation
between prolonged and frequent use of ultrasound and
abnormal neuronal migration in mice. A meta-analysis of
several ultrasonography studies found no statistically
significant harmful effects from ultrasonography, but
mentioned that there was a lack of data on long-term
substantive outcomes such as neurodevelopment.

8. Obstetrical Ultrasound
• Indications:
• Unsure last menstrual period
• Vaginal bleeding during pregnancy
• Uterine size not equal to expected for dates
• Use of ovulation-inducing drugs confirm early pregnancy
• Obstetric complications in a prior pregnancy: ectopic, preterm
delivery
• Screen for fetal anomaly: abnormal serum screens, certain drug
exposure in early pregnancy, maternal diabetes.
Rhisoimmunization
• Postdate fetus
• Twins (monochorionic)
• Intrauterine growth restriction (IUGR)
RADIUS study (1993) did not support routine US screening

9. Obstetrical Ultrasound
• 1st. Trimester (less than 12 weeks)
• Gestational sac location / size / shape
• Embryo
• Yolk sac
• Amnion
• Fetal cardiac activity
• Placental position/Umbilical cord
• Amnionitic fluid
• Fetal morphology>11 weeks)
• Cranium
• Heart
• Stomach/Bladder/Cord insertion/presence of limbs, hands
and feet

10. Types of Ultrasonography
• Trans Abdominal Ultrasonography (TAS)
• Trans Vaginal Ultrasonography (TVS)
• Doppler Ultrasound
• Tissue Harmonic Imaging (THI)
• Three-dimensional Ultrasound (3-D USG

11. Trans Abdominal Ultrasound
(TAS)
• Major technique for imaging in 2nd and 3rd trimester
• Patient to have full bladder because
– Pushes the uterus out of the pelvis
– Provides an acoustic window
– Displaces pelvic bowel loop superiorly
• Real-time ultrasound equipment includes:
– Sector transducers, when access is limited
– Linear curved array transducers, for less distortion and greater field
of view

13. Trans Vaginal Ultrasound
(TVS)
• Method of choice for
– Monitoring infertility disorders
– Diagnosis of ectopic pregnancy
– Differentiation of normal and abnormal 1st
trimester pregnancy
– Diagnosis of congenital anomalies in 2nd trimester
• Patient to have empty bladder because
– Uterus will be pushed posteriorly out of the field of
view of the transducer

14. Trans Vaginal Ultrasound (TVS) cont
• Specially designed high frequency transducers
• Higher resolution images
• Favorable for obese patients or in early stage of pregnancy
• Limitations include
– Reduced beam penetration
– More invasive nature of the technique

16. Doppler Ultrasonography
• Most widely employed for detection of:
– Fetal cardiac pulsation
– Pulsation in various fetal blood vessels
• Doppler waveform for useful information
about intra-uterine growth retardation
• Use remains controversial due to increased
power

18. Tissue Harmonic Imaging
(THI)
• Processing of lower amplitude, higher
frequency waveforms accompanying
fundamental frequency
• Lesser clutter and scatter
• Better visualization of fetal structure

19. Three-dimensional USG (3-D)
• 3-Dimensional “cleaner” image of the scanning
• Transducer captures series of images
• 3-D processing done by Computer
• Significant improvement in identifying
– Cleft lips
– Spina bifida
– Polydactyl

21. Application of Ultrasound in
Trimesters
• First Trimester
– Commonly performed at 9-12 weeks
• 2nd and 3rd Trimester
– Commonly performed at 18-20 weeks

22. Obstetrical Ultrasound
• Pre and peri-ovulation (1-2 weeks): ovarian
follicle matures and ovulation
• Conceptus (3-5 weeks): Corpus luteum,
fertilization, morula, blastocyst, bilaminar
embryo
• Embryonic (6-10 weeks): Trilaminar C-
shaped embryo
• Fetal Phase: (11-12 weeks):

23. Obstetrical Ultrasound
(TVU)
Gestational sac: seen at 4 weeks, fluid
filled with echogenic border, grow at least
0.6 mm daily.15
Yolk sac: 33 days (4.7 wk)
Embryonic echoes: 38 days (5.4 w) with
embryo at 6 wk
In a normal pregnancy, the embryo should
be visible if the gestational sac is 25 mm
or larger in diameter.

24. Obstetrical Ultrasound
• An intrauterine gestational sac should be visualized by
transvaginal ultrasound with β-hCG values between 1000
and 2000 IU and abdominal exam 5500-6500 IU
• Visible heart activity: 43 days (6.1w)
• Normal heart rate at 6 weeks: 90-110 bpm
• At 9 weeks:140-170 bpm.
• At 8-9 weeks if nl heartbeat: no bleeding 3%loss
bleeding 13% loss
• At 5-8 weeks a bradycardia (<90 bpm) is associated with a
high risk of miscarriage.

25. Obstetrical Ultrasound
• CRL(Crown Rump Length):
• Longest length excluding
limbs and yolk sac
• Made between 7 to 13 weeks
• 3 days: 7-10 weeks
• 5 days: 10-14 weeks
• Fetal CRL in centimeters plus
6.5 equals gestational age in
weeks

26. Obstetrical Ultrasound
• Ultrasound findings in a
pregnancy destined to abort
include:
• A poorly-defined, irregular
gestational sac
• A large yolk sac (6 mm or
greater in size)
• Low site of sac location in the
uterus
• Empty gestational sac at 8
weeks' gestational age (the
blighted ovum).

27. Obstetrical Ultrasound
• First Trimester Screening
• In 2007, the American College of Ob Gyn endorsed offering
aneuploidy screening to all gravidas
• Performed between 11 and 13 weeks 6 days (fetal crown–rump
length 42–79 mm).
• Fetal nuchal translucency and maternal blood, β-hCG and
pregnancy-associated plasma protein A (PAPP-A).
• This test can detect approximately 60-85% of fetuses with
Down syndrome, with a 5% false positive rate.2
• Abnormal screen can increase the risk of genetic, other
aneuploidiesand other cardiac anomalies

28. Obstetrical Ultrasound
• Nuchal translucency:
• Translucent space between the back of the
neck and the overlying skin
• The scan is obtained with the fetus in sagittal
section and a neutral position .
• The fetal head (neither hyperflexed nor
extended, either of which can influence the
nuchal translucency thickness).
• The fetal image is enlarged to fill 75% of the
screen, and the maximum thickness is
measured, from leading edge to leading edge.
(inner to inner measurement)
• It is important to distinguish the
nuchallucency from the underlying amnionic
membrane.
• > 6 mm considered abnormal

29. Measurement of Nuchal Translucency
Nuchal
Translucenc
y

32. Two gestational sacs,
containing a yolk sac
•Identification and documenting the fetal
number

33. Evaluation of Uterus and Adnexal
structures
Uterus and cervical plug

38. A) The following qualified persons may be considered
eligible to perform USG for purposes and indications given
under the provisions of the PCPNDT Act/ Rules.
I. Radiologist having Post Graduate Qualification in
Radiology/ Imaging Sciences, as specified in the schedule
I/II/III of the IMC Act of 1956. (Modified because of
different PG degrees and their nomenclature in different
states.)

39. II. Ob/ Gyn. having Post Graduate Qualification in Ob./ Gyn.,
as specified in the schedule I/II/III of the IMC Act of 1956.
III. DNB qualification in Radiology /Obs/Gyn, as
equated and as per provisions of the Medical Council of
India for equivalence.
IV. MBBS graduate from recognized University in India
or any other foreign medical graduate qualification
recognized by the Medical Council of India with Six (6)
months of Obs/Gyn ultrasound training at any Govt.
recognized teaching institute

40. DUTIES OF REGISTERED
CENTRE
• Person conducting ultrasonography on a
pregnant women shall keep complete record
thereof in the clinic/centre in Form - F and
any deficiency or inaccuracy found therein
shall amount to contravention of provisions
of section 5 or section 6 of the Act, unless
contrary is proved by the person conducting
such ultrasonography.

41. DUTIES OF REGISTERED
CENTRE
1 Should not involve in fetal sex detection
2. Should keep copy of Bare act of PC-PNDT
3. Should display Board in local language also
4. Copy of Form D/E/F / Summary of these Forms
must be submitted by 5th of every month in the
office of appropriate authority.

42. Take Home Message
Performed with proper guidelines ROUTINE
USG IN PREGNANCY can predict many
problems and be a good watch dog for fetal
and maternal wellbeing

43. Obstetrical Ultrasound