ultrasound Flashcards
What are the main uses of ultrasound in obstetrics?
Ultrasound in obstetrics is used for fetal monitoring, detecting abnormalities, and assessing fetal growth and development.
How is ultrasound used in gynecology?
In gynecology, ultrasound helps evaluate the female pelvis, detect masses, and assess reproductive organs.
What are the therapeutic applications of ultrasound?
Therapeutic applications include guiding procedures like IVF, amniocentesis, and cordocentesis.
Explain the process of ultrasound imaging using piezoelectric crystals.
Ultrasound imaging uses piezoelectric crystals in a transducer that convert electric signals into high-frequency sound waves, which reflect off tissues to create images.
Why is gel applied to the abdomen before an ultrasound scan?
Gel ensures proper transmission of sound waves by eliminating air gaps between the skin and transducer.
What is the frequency range for abdominal and transvaginal transducers?
Abdominal transducers use 3.5–5.0 MHz, while transvaginal transducers use 5.0–7.5 MHz for better detail.
How does abdominal ultrasound compare to transvaginal ultrasound in terms of detail and coverage?
Abdominal ultrasound provides a panoramic view but lower detail, while transvaginal ultrasound offers better detail but a smaller field of view.
Describe the differences between 2D, 3D, and 4D ultrasound imaging.
2D ultrasound sends sound waves straight down; 3D ultrasound captures width, height, and depth; 4D ultrasound provides real-time motion imaging.
Why does a transvaginal scan require an empty bladder?
A transvaginal scan requires an empty bladder to allow closer access to pelvic organs.
What are the safety aspects of ultrasound compared to X-rays?
Ultrasound is safer than X-rays as it does not use radiation, only sound waves.
What is cavitation, and when does it become significant in ultrasound?
Cavitation is the potential increase in body temperature from prolonged ultrasound exposure, though it is generally insignificant.
List at least five clinical applications of ultrasound in obstetrics.
Clinical applications include assessing fetal viability, detecting malformations, determining gestational age, evaluating placenta and amniotic fluid, and identifying multiple gestations.
How is ultrasound used in the assessment of multiple gestation?
Multiple gestations are assessed using ultrasound to determine chorionicity, fetal growth, and presentation.
What are some gynecological conditions diagnosed using ultrasound?
Gynecological conditions diagnosed with ultrasound include fibroids, ovarian masses, pyo/hydrosalpinx, endometrial hyperplasia, and cancer.
How does ultrasound assist in procedures like amniocentesis and cordocentesis?
Ultrasound assists in procedures like chorionic villus sampling (CVS), amniocentesis, and cordocentesis by guiding needle placement.
At what gestational age can a gestational sac be visualized on ultrasound?
A gestational sac can be seen as early as 4.5 weeks.
When can fetal heartbeats and blood flow be detected via ultrasound?
Fetal heartbeats and blood flow can be detected by 6-7 weeks.
Which fetal measurement is used for dating pregnancy, and during what weeks is it most accurate?
Crown-rump length (CRL) is used for dating pregnancy between 7 and 13 weeks.
Name the four fetal growth parameters commonly measured after 13 weeks.
The four fetal growth parameters are biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL).
When are the routine obstetric ultrasound scans recommended?
Routine scans are done at 7 weeks, 18-22 weeks, and 32-34 weeks.
What are the key objectives of the first-trimester ultrasound scan?
The first-trimester scan confirms pregnancy, excludes ectopic pregnancy, checks cardiac activity, and estimates gestational age.
What is assessed during the second-trimester ultrasound scan?
The second-trimester scan checks for congenital malformations, multiple pregnancies, fetal growth, and placental position.
What is the primary focus of the third-trimester ultrasound scan?
The third-trimester scan evaluates fetal size, growth, and presentation.
What methods are used to measure amniotic fluid levels?
Amniotic fluid is measured using deepest vertical pool (DVP) or amniotic fluid index (AFI) from 24-26 weeks.
What are anomaly scans, and why are they performed?
Anomaly scans assess fetal abnormalities and structural defects.
List at least five indications for an anomaly scan.
Indications for anomaly scans include family history of anomalies, maternal diabetes, abnormal screening tests, multiple gestation, and suspected IUGR.
Which major fetal malformations can typically be detected at the routine anomaly scan?
Major fetal malformations detected include anencephaly, encephalocoele, cystic hygroma, and abdominal wall defects.
Why might some fetal abnormalities require specialist ultrasound examination?
Some abnormalities, like renal and cardiac defects, may require a specialist scan for diagnosis.
What are the advantages of transvaginal scanning (TVS)?
Advantages of TVS include better anatomical detail and closer proximity to pelvic structures.
What are the indications for TVS in gynecology and obstetrics?
Indications for TVS include early pregnancy assessment, gynecologic sonography, and suspected ectopic pregnancy.
How does TVS help in early first-trimester sonography?
TVS in early pregnancy helps detect gestational sac, yolk sac, embryo, and fetal heartbeat.
Why is TVS useful in detecting placenta previa?
TVS is useful for placenta previa as it provides a clearer view of the cervix and lower uterine segment.
How does TVS aid in the diagnosis of ectopic pregnancy?
TVS is preferred for ectopic pregnancy diagnosis as it provides high-resolution imaging of adnexal structures.
What are the normal characteristics of ovaries on TVS?
Normal ovaries on TVS are clear with a volume <10 cm³, but they can sometimes be difficult to locate.
Differentiate between follicular and corpus luteum cysts on ultrasound.
Follicular cysts are thin-walled, 3-8 mm, and clear, while corpus luteum cysts have thicker walls and echogenic content.
