Sono Science
First Trimester Scans
Fetal/Placental Assessment
Amniotic Fluid
Miscellaneous Measurements
100

Do high or low frequency yield better image resolution 

High 
100

What is suboptimal dating? 

Confirming US >22w0d 

100

When should anatomy scans be performed? 

18-22 weeks 

100

What is a normal AFI? 

5-25cm 

100

Define placenta previa 

Placental edge within 2cm of internal os 

200

What is gain? 

Gain refers to amplitude of returning sound waves, controlling brightness vs. darkness of screen

200

What is the discrepancy of LMP to US to redate gestational age at <9 weeks? 

>5 days 

200

Name 5 indications for a fetal echo 

Suspected fetal cardiac structural or functional abnormality, heart rate abnormality or arrhythmia, extracardiac anomaly or hydrops, chromosomal abnormality, NT >3.5mm, IVF, monochorionic twin gestation, 1st degree relative to fetus with cardiac defect, 1st or 2nd degree relative to fetus with mendelian syndrome and childhood cardiac manifestation, prior fetus with heart block in setting of anti-Ro or anti-La antibodies, retinoid exposure, pregestational diabetes, or phenylketonuria 

200

What is severe polyhydramnios? 

>35cm 

200

What artery is measured to assess for fetal anemia? 

Middle Cerebral Artery 

300

What frequency do ultrasound waves travel at?

Above 20,000 Hz 

300

When should nuchal translucency be measured? 

11 to 14 weeks

300

Define velamentous cord and what can be associated with velamentous cord insertion 

When the umbilical cord inserts into the membranes, not the placenta itself. The umbilical vessels travel unprotected by Wharton jelly and can be a risk factor for vasa previa

300

Top 3 etiologies for polyhydramnios 

Idiopathic, Fetal anomalies, Diabetes 

300

What measurement reliably identifies fetuses with moderate to severe anemia?  

MCA peak systolic velocity of 1.5 multiples of median 
400

What two indices are all ultrasound devices required to display for safety? 

Mechanical and thermal 

400
4 US findings diagnostic of pregnancy failure 

1) CRL >7mm no heartbeat

2) Mean sac diameter 25mm or greater with no heartbeat 

3) Gestational sac w/ no yolk sac and no heartbeat 14 days later 

4) Gestational sac w/ yolk sac and no heartbeat 11 days later 

400

Risk of PAS w/ 3 prior CS and placenta previa? 

61% 

400

IOL timing for oligohydramnios 

36w0d to 37w6d 

400

What percent of major fetal anomalies can be identified on standard US? 

Approx 60% 

500

Ultrasound transducers contain what type of crystals that convert electrical energy into sound waves?

Piezoelectric crystals

500

What NT measurement is associated with increased risk for fetal structural or genetic abnormalities? 

>3mm 

500

Name 3 of 5 US criteria for Placenta Accreta Spectrum 

1) Placenta Lacunae 

2) Attenuation or thinning of the retroplacental myometrium 

3) Disruption of bladder-uterine serosal interface 

4) Bridging vessels from bladder - serosal interface 

5) A placental "bulge" that pushes outward and distorts contour of uterus 

500

Fetal urination per day in late pregnancy 

1L/day 

500

Why measure Umbilical Artery for S/D ratio? And what is an abnormal measurement?

Differs from other vessels that it normally has forward flow throughout the entire cardiac cycle. Abnormal >95% for gestational age.