High-Risk Fetal Doppler, Fetal Growth Restriction, and Placental Pathologies — WACS Viva & Clinical Scenarios (Obstetric and Gynaecological Imaging)

Exam-style high-risk fetal doppler, fetal growth restriction, and placental pathologies viva scenarios with examiner probes and model answers for Radiology…

Scenarios covered

• SCENARIO 1: A 28-year-old primigravida at 28 weeks of gestation presents with severe early-onset fetal growth restriction. Detail the characteristic sequential progression of fetoplacental and central hemodynamic Doppler waveform abnormalities, discuss the underlying pathophysiological mechanisms of the brain-sparing reflex and ductus venosus flow reversal, and outline the clinical surveillance thresholds that mandate immediate delivery.
• SCENARIO 2: Examine the provided transabdominal and transvaginal grey-scale and color Doppler sonograms of a 34-year-old woman at 32 weeks of gestation with two previous caesarean deliveries presenting with an anterior low-lying placenta. Identify the specific sonographic features that confirm the diagnosis of placenta accreta spectrum (PAS), distinguish between placenta accreta, increta, and percreta, and outline the radiological staging criteria used to guide multidisciplinary surgical planning.
• SCENARIO 3: A 30-year-old Rh-negative pregnant patient at 26 weeks of gestation with high anti-D antibody titers is referred for assessment of fetal anemia. Explain the physiological rationale and Doppler technique for measuring middle cerebral artery peak systolic velocity (MCA-PSV), define the diagnostic threshold for moderate-to-severe fetal anemia, and describe the sonographic signs of progression to non-immune hydrops fetalis.
• SCENARIO 4: Discuss the role of uterine artery Doppler waveform analysis in the first and second trimesters for the prediction and screening of pre-eclampsia and fetal growth restriction. Detail the anatomical insonation technique, the evolution of normal versus abnormal flow velocity waveforms including diastolic notching, and the quantitative cut-offs for resistance index and pulsatility index.
• SCENARIO 5: A 24-year-old woman at 30 weeks of gestation presents with acute vaginal bleeding and lower abdominal pain. Formulate a comprehensive radiological differential diagnosis distinguishing concealed and revealed placental abruption from placenta previa, vasa previa, and chorioangioma. Detail the ultrasound findings, color Doppler criteria, and diagnostic pitfalls associated with acute retroplacental hematomas.