Post on 17-Jan-2016
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ULTRASOUND IN ULTRASOUND IN
OBSTETRICS & GYNECOLOGYOBSTETRICS & GYNECOLOGY
Hidayat Wijayanegara
Department of Obstetric & Gynecology School Medicine Padjadjaran University /
Hasan Sadikin Hospital Bandung
Ultrasound examination : Reveals vital information Fetal anatomy Fetal environment Growth Well being
No biological hazard
The first obstetrical application of USG
imaging : Ian Donald (1958)
Sound waves of frequencies higher than
the hearing limit of the human ear are
called ultrasonic waves
The limit is by convention 20 KHz
Medical practice frequencies between
1-10 MHz are commonly used
Ultrasound
Technology :
Sound waves reflecting back from Sound waves reflecting back from
the fetus or image structure the fetus or image structure
displayed on the ultrasound screendisplayed on the ultrasound screen
Alternating current is applied to a Alternating current is applied to a
transducer made of piezoelectric transducer made of piezoelectric
material material intermittent high intermittent high
frequency sound waves exceeding frequency sound waves exceeding
20,000 cps are generated 20,000 cps are generated
The transducer emits a pulse of sound waves The transducer emits a pulse of sound waves that passes through the layer of soft tissuethat passes through the layer of soft tissue
Interface between structures of Interface between structures of
different tissue densities different tissue densities
Some of the energy is reflected back Some of the energy is reflected back to the transducer to the transducer
A small electrical voltage A small electrical voltage
Display on a screen Display on a screen
Bone is dense (echogenic) Bone is dense (echogenic) white on the white on the screenscreen
Fluid (anechoic) Fluid (anechoic) black black Soft tissues Soft tissues varying shade of gray varying shade of gray
1.Operator control1.Operator control 6. Visual 6. Visual informationinformation
2.Transducer drive2.Transducer drive 5. Electric 5. Electric informationinformation
3.Ultrasound pulses 3.Ultrasound pulses 4. Acoustic 4. Acoustic informationinformation
The diagnostic ultrasound visualization The diagnostic ultrasound visualization methodmethod
OperatorOperator
InstrumentInstrument
TransducerTransducer
Tissue interactionTissue interaction
TransabdominalTransabdominal Scanning : Scanning :
Performed with 3.5 – 7 MHzPerformed with 3.5 – 7 MHz
Safety : no confirmed biological Safety : no confirmed biological
effects in mammalian tissue have effects in mammalian tissue have
been demonstrated in the been demonstrated in the
frequency range of medical frequency range of medical
ultrasound (AIUM, 1991)ultrasound (AIUM, 1991)
Choice of equipment :
Transabdominal scanningTransabdominal scanning
Transvaginal scanningTransvaginal scanning
Doppler and color flow imagingDoppler and color flow imaging
3D3D
2D
Biophysical mechanism :
Are not fully understood
The effects of ultrasound on various biological entities may be due to one or a combination of any of the following :
1. Heating effects
2. Cavitational effects
3. Mechanical effects
Are associated only with high Are associated only with high average intensities and not average intensities and not found in diagnostic equipmentfound in diagnostic equipment
Preparation of the patient
Ultrasound beam cannot penetrate gasUltrasound beam cannot penetrate gas The interface created by gas The interface created by gas the sound the sound
beam totally reflectedbeam totally reflected Water Water excellent transmission medium excellent transmission medium The distension of bladder The distension of bladder displaces displaces
intestinal loop intestinal loop acoustic windowacoustic window to the to the pelvic structure pelvic structure
Patient should be scanned with a full Patient should be scanned with a full bladder bladder
The full bladder technique offer :The full bladder technique offer :
1. It displaces the fetal head upwards1. It displaces the fetal head upwards
2. It allow visualization of the cervix2. It allow visualization of the cervix
Coupling agents
A gel or an oil A gel or an oil eliminates the air eliminates the air interface between the transducer interface between the transducer and the patient’s skinand the patient’s skin
Scanning technique The patient is on your rightThe patient is on your right The machine is on your leftThe machine is on your left Work in dim lighting to help Work in dim lighting to help
reflection on the screen reflection on the screen
Indications for ultrasound examination
Gynecology : - Uterus, Ovaries, AdnexaGynecology : - Uterus, Ovaries, Adnexa
- - Abnormal bleeding, pelvic pain & Abnormal bleeding, pelvic pain & discomfortdiscomfort
- IUCD location and complications- IUCD location and complications
- Pelvic mass reveals mass or - Pelvic mass reveals mass or enlargement of pelvic organ enlargement of pelvic organ
- Evaluation of masses palpable - Evaluation of masses palpable
- Ovulation induction therapy - Ovulation induction therapy
- Guidance for abscess drainage- Guidance for abscess drainage
Uses of ultrasound in gynecology
1. Determine the size and location of lesions2. Characteristics of the lesion: cystic, complex
or solid3. Determine if mass is uterine or extrauterine4. Evaluate the extent of pelvic inflammatory
disease or endometriosis and follow-up5. Follow the course of a simple cyst: regression,
etc.6. Locate the position of an intrauterine device7. Detection of ascites8. Radiation therapy planning
Obstetrics :
Routine obstetrical ultrasound scan: 18-20 weeks
1st Trimester : Confirm pregnancy, viability, gestational age Rule out :
Ectopic pregnancyGestational trophoblastic diseaseForeign bodies
Large for dates – fibroid, uterine malformation, multiple gestation
Small for dates – missed abortion, blighted ova
Ovaries, rule out adnexal lesions, uterine position, rule out uterine anomalies
Undetermined etiology of vaginal bleeding
Suspected complications, i.e subchorionic hematome
22ndnd and 3 and 3rdrd trimester : trimester :
Confirm viability, gestational age, fetal number
Evaluated fetal growth, anatomy, lie, position, follow up anomaly
Evaluate placenta, AFV, cord
Biophysical profile for fetal well being
Vaginal bleeding
Components of basic ultrasound examination according to Trimester pregnancy
1st trimester Gestational sac
location
Embryo identification
Crown rump length (CRL)
Fetal heart rate motion
Fetal number
Uterus & adnexal evaluation
2nd and 3rd trimester
Fetal number Presentation Fetal heart motion Placental location Amniotic fluid volume Gestational age Survey of fetal
anatomy Evaluation for
maternal pelvic mass
Ultrasonic Landmark Occurence
(weeks of gestation)
Gestational sac 5 – 6 weeks
Fetal embryonic pale 6 – 7 weeks
Detection of fetal life 7 – 8 weeks
Placenta 8 – 10 weeks
Loss of gestational sac 11 – 13 weeks
Fetal head 11 – 14 weeks
(Biparietal diameter)
Evaluation of ultrasound to determine gestational age
Crown Rump Length (CRL)
Biparietal diameter (BPD)
Femur Length (FL)
Head Circumference (HC)
Abdominal Circumference (AC)
Accuracy of ultrasound measurement for different gestational groups
Ultrasound parameter Accuracy
Gestational sac diameter + 7 days Crown Rump Length + 3-5 days BPD second trimester + 1 to 1.5
weeks BPD third trimester + 2 to 4
weeks FL second trimester + 1 to 1.5
weeks FL third trimester + 3 to 3.5
weeks Multiple parameter (2nd trimester) + 1.5
weeks Multiple parameter (3rd trimester) + 2.5
weeks
Summary
1. Physics of ultrasound
The ultrasound used in clinical practice is limited to frequencies in the range of 1-10 cycles per second (1-10 MHz)
In Obstetrics : 3.5 MHz and 5 MHz
2.UltrasoundIs produced when transmitted pulses of sound from the transducer cross body structures and reflect energy back to the transducer from the interfaces of organs
3. Ultrasound in Obstetrics Confirmation of an intrauterine
pregnancies
Exclusion of an ectopic pregnancies
Assessment of an intrauterine pregnancies
Determination of gestational age :
Are uncertain of the date of conception
Resolving discrepancies between gestational age and uterine size :
Large for dates
Small for dates
Investigation of uterine bleeding Visualization for high risk procedures
Amniocentesis Chorionic villous sampling Cordocentesis
Evaluation of fetal well-being Distinguish congenital malformation Biophysical profile
Doppler flow velocimetry IUGR 60-80% of the time in cases where the
umbilical artery waveforms are abnormal due to uteroplacental insufficiency