Fetal blood flow velocimetry by phase-contrast MRI using a new triggering method and comparison with Doppler ultrasound in a sheep model: a pilot study.
OBJECTIVE
We present the first study demonstrating the feasibility of antenatal blood flow velocimetry performing ECG triggered phase-contrast (PC)-MRI in the fetal aorta by using a newly developed Doppler ultrasound trigger.


METHODS
Five pregnant sheep carrying singleton fetuses (gestational age 121 days) were anesthetized to undergo fetal 2D PC-MRI in the fetal descending aorta (1.5 T) using a newly developed MR-compatible Doppler ultrasound trigger for fetal cardiac triggering. Inter-operator variability was assessed for PC-MR measurements and reproducibility was tested by repeated scans in one fetus. Inter-modality comparison was performed by Doppler ultrasound velocimetry.


RESULTS
Fetal cardiac triggering was possible in all examinations. PC-MR velocimetry revealed a mean inter-operator variability of 3 ± 5%. Average peak systolic flow velocities of 62.5 ± 4.4 cm/s were in good agreement with Doppler ultrasound measurements of 62.0 ± 9.2 cm/s (p (Lord's U test) ≫ 0.05).


CONCLUSIONS
Fetal PC-MR velocimetry was successfully performed using the newly developed MR-compatible Doppler ultrasound trigger for intrauterine fetal cardiac triggering, demonstrating high inter-operator and inter-modality agreement. This new method has the high potential for alternative assessment of hemodynamic decompensation of the fetal circulation.
Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany, b.schoennagel@uke.uni-hamburg.de.
Bjoern P
BP
Schoennagel
Chressen C
CC
Remus
Jin
J
Yamamura
Fabian
F
Kording
Manuela
M
Tavares de Sousa
Manuela Tavares
MT
de Sousa
Kurt
K
Hecher
Roland
R
Fischer
Friedrich
F
Ueberle
Matthias
M
Boehme
Gerhard
G
Adam
Hendrik
H
Kooijman
Ulrike
U
Wedegaertner
D000818:Animals; D001011:Aorta / Q000033:anatomy & histology / Q000196:embryology* / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D005260:Female; D005312:Fetal Blood / Q000166:cytology / Q000000981:diagnostic imaging / Q000502:physiology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D018810:Magnetic Resonance Angiography / Q000379:methods*; D010865:Pilot Projects; D011247:Pregnancy; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012756:Sheep; D018608:Ultrasonography, Doppler / Q000379:methods*; D016216:Ultrasonography, Prenatal / Q000379:methods*