Ultrasound in Obstetrics and Gynaecology Flashcards
(27 cards)
What is the role of ultrasound in obstetrics and gynaecology?
Ultrasound is a safe, non-invasive diagnostic tool for assessing the foetus, uterus, ovaries, and adnexa.
What is the principle behind ultrasound technology?
It works by converting electrical energy to high-frequency sound waves, which reflect back to form images.
What are the common transducer frequencies for abdominal and transvaginal scans?
Abdominal: 3.5–5.0 MHz; Transvaginal: 5.0–7.5 MHz.
What are the differences between abdominal and transvaginal scans?
Abdominal: panoramic view, less detail; Transvaginal: more detail, closer structures.
List the different types of ultrasound imaging in O&G.
2D, 3D, 4D (real-time), and Transvaginal scanning (TVS).
Is ultrasound safe during pregnancy?
Yes, it is generally safe as it uses sound waves, not ionising radiation.
What is “cavitation” in ultrasound?
It is a rise in tissue temperature from sound waves; only significant in prolonged exposure.
List 5 major clinical indications for ultrasound in obstetrics.
Dating, foetal growth, viability, congenital malformations, multiple gestation.
List 5 clinical indications for ultrasound in gynaecology.
Fibroids, ovarian masses, endometrial pathology, molar/ectopic pregnancy, monitoring in infertility/IVF.
What are the first ultrasound milestones in pregnancy?
4.5 weeks: gestational sac; 5 weeks: yolk sac; 5.5 weeks: embryo; 6–7 weeks: heartbeat.
At what gestational age is the yolk sac typically seen?
Around 5 weeks gestation.o
When is the foetal heartbeat visible on ultrasound?
Around 6–7 weeks gestation.
What is crown-rump length (CRL) used for?
Dating of pregnancy (most accurate between 7–13 weeks).
What are the key biometric measurements used to assess foetal growth?
Biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL).
When should the 1st, 2nd, and 3rd trimester scans be performed?
1st: 7–13 weeks; 2nd: 18–22 weeks; 3rd: 32–34 weeks.
What are the objectives of the 1st trimester scan?
Confirm pregnancy, exclude ectopic/molar pregnancy, detect heartbeat, measure CRL.
What are the objectives of the 2nd trimester scan?
Detect anomalies, confirm growth and gestational age, assess placental position.
What is assessed during the 3rd trimester scan?
Foetal growth, presentation, amniotic fluid levels.
How is amniotic fluid assessed via ultrasound?
Deepest vertical pool (DVP) or amniotic fluid index (AFI) from 24–26 weeks.
What are common indications for anomaly scans?
Family history, maternal diabetes, abnormal screening, suspected anomalies, advanced maternal age.
Name 4 foetal anomalies that can be detected on routine scans.
Anencephaly, encephalocoele, cystic hygroma, abdominal wall defects.
What is transvaginal scanning (TVS) and when is it used?
TVS involves placing a probe inside the vagina to get detailed images of pelvic organs.
What frequency range is used in TVS?
5–7.5 MHz.
What are the advantages of TVS over transabdominal scanning?
Greater detail and proximity to uterus and ovaries.
