Cheat Sheet for Dopplers (Per Dr. Brennan)
Umbilical Artery Dopplers
• Measurements should be made in a free cord loop.
• Use pulsed wave Doppler to obtain waveform.
• Use High Q to measure velocities of a minimum of 3 waveforms.
• Repeat on a minimum of 2 cord segments. Obtain a third measurement if results in one segment are elevated.
• Umbilical artery: greater then 90th percentile of RI or SD is abnormal
o Obtain MCA and DV Dopplers.
MCA Dopplers
• Indications:
o Abnormal UA dopplers
o IUGR (<10th percentile for growth)
o Decreased AC measurement (<10%)
o Rh sensitization, iso-immunization
o Maternal infection possibly resulting in fetal anemia (parvo virus)
o Monochorionic twins after 16 weeks as part of TTTS protocol.
o Umbilical Vein Varix
o CPAM
o Placental Mass
• Anemia:
o MCA PSV MoM value should be below 1.5. Anything above 1.5 is abnormal
• IUGR:
o MCA PI percentage value: values below 3% or above the 97% are abnormal.
o CPR normal >10%.
• MCA PI percentage value: values b<3% or >97% are abnormal.
• Procedure:
o From standard biometry plane, shift toward base of skull.
o Use color to locate the middle cerebral arteries extending anteriorly from Circle of Willis toward the orbits. MAGNIFY image.
o Position Doppler gate near origination of vessel, perpendicular to vessel resulting in blood flow parallel to sound beam.
o Obtain 3-5 identical waveforms.
o Use High Q to measure velocities of a minimum of 3 waveforms.
o Optimal image will not require angle correct. When ideal image not obtained, use angle correct.
o Perform only when the fetus is NOT breathing.
Ductus Venosus Dopplers
• Indications:
o Fetal Echocardiogram or fetal echo follow up
o Abnormal UA and MCA Dopplers
o IUGR
o Fetal anemia
o Umbilical Vein Varix
o Fetal congenital heart defect
o Persistent right umbilical vein
o A/V Malformation (chorioangioma, Vein of Galen aneurysm, varix, etc.)
o Monochorionic twins after 16 weeks as part of TTTS protocol.
• Procedure:
o May be obtained in mid-sagittal, longitudinal view of fetal trunk, OR transverse view of upper fetal abdomen.
o Use color to isolate aliasing seen near where the umbilical vein courses abruptly right. Use zoom box and a narrow color box to optimize the image
o Doppler gate should be positioned directly over aliasing.
o Waveform is bi-phasic with forward flow during the entire cardiac cycle.
o Use High Q to measure velocities of a minimum of 3 waveforms.
o Perform only when the fetus is NOT breathing.
o Ductus: anything above 1 is abnormal for all docs except Dr. Joffe
o For Dr. Joffe look at the ductus graph on the sheet labeled Normal Values for Cardiac Performance Parameters.
