SDMS CME Credit – Establishing Reference Ranges for Doppler Parameters of the Fetal Aortic Isthmus in the Third Trimester

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Authors: Elham Eghbali, MD, Maghsoud Ezzati Khatab, MD, Mahboube Taheripour, MD, Zahra Nasiroghli Khiabani, MD, Mehran Jaberinezhad, MD, Mahdi Hemmati Ghavshough, MD, and Farzaneh Khodaei, MD

Category: OB/GYN [OB]

Credit: 1.00 SDMS CME Credit

Objectives: After studying the article, you should be able to:

• • Describe the fetal aortic isthmus (AoI) and its role in fetal circulation.

• • Discuss the technique for obtaining fetal AoI Doppler waveforms.

• • Summarize normal Doppler parameters for the fetal AoI in healthy pregnancies.

• 1. Which of the following is the link between the aortic and pulmonary circulations in a fetus?

• B. Fetal aortic isthmus (AoI)

• C. Ductus arteriosus

• D. Left common carotid artery

2. The vascular properties of the fetal AoI make it a critical marker for assessing:

A. Fetal heart rate

B. Amniotic fluid index

C. Fetal lung maturity

D. Fetal hemodynamics

3. What statistical method was used during the study to evaluate the reference intervals?

A. Royston and Wright

B. Brenner

C. Quadratic regression model

D. Hadlock

4. According to the article, several studies have shown that the AoI acts not only as a marker of fetal health but also as a predictor of:

A. Estimated due date and fetal weight

B. Fetal growth ratio

C. Perinatal outcomes

D. Fetal lung maturity

5. How many pregnant patients, with a gestational age (GA) between 28 and 40 weeks of pregnancy, agreed to participate in the article’s cross-sectional study?:

A. 253

B. 325

C. 523

D. 230

6. To determine reference values, the study in the article examined the Doppler findings of AoI indices in:

A. Healthy pregnancies

B. Intrauterine growth restriction (IUGR) fetuses

C. High-risk fetuses

D. Diabetic patients

7. Which view was used in the study to obtain Doppler parameters of the fetal aorta?

A. Only the three-vessel view (3VV)

B. The subcostal view

C. A longitudinal view

D. The three-vessel and trachea view (3VT)

8. Which regression models were chosen to estimate the association between AoI variables and GA during the study?

A. Linear and quadratic

B. Cubic, linear, and quadratic

C. Axial, cubic, and linear

D. Quadratic and axial

9. What Doppler ratio was measured for each of the conducted tests in this study?

A. Peak systolic velocity (PSV)

B. Isthmic systolic index (ISI)

C. Systolic/diastolic (S/D)

D. Pulsatility index (PI)

10. According to the limitations listed in the article, what should future studies include in their investigations?

A. IUGR fetuses and fetal isthmic flow index (IFI)

B. Peak systolic velocity (PSV)

C. Time-averaged maximum velocity (TAMXV)

D. Isthmic systolic index (ISI)