The human placenta: Function and morphological assessments using ultrasound and magnetic resonance elastography

s / Placenta 45 (2016) 63e133 74 P1.6 THE HUMAN PLACENTA: FUNCTION AND MORPHOLOGICAL ASSESSMENTS USING ULTRASOUND AND MAGNETIC RESONANCE ELASTOGRAPHY Richard K. Miller , Stephan McAleavey , Juvenal Ormachea , Eva Pressman, Loralei Thornburg , David Dombroski , Jianhui Zhong, Marvin Doyley , Ronald W. Wood, Jonathan Carrol-Nellenback , Ollivier Hyrien , Philip Katzman , Christopher Stodgell , Kam Szlachetka, Henry Wang, Kevin Parker . University of Rochester School of Medicine and Dentistry, Rochester, New York, USA; University of Rochester Haijm School of Engineering, Rochester, New York, USA Objective: In utero evaluations of placental anatomy and function offer the promise of associating placental pathophysiology with neonatal outcomes, and thus potential for enhanced management of perinatal complications and improved long-term health of the mother and child. Ultrasound Elastography (USE) and Magnetic Resonance Elastography (MRE) provide means to evaluate tissue stiffness in utero. In conjunction with measures of vascular anatomy and perfusion, we can test mechanistic hypotheses about the relationship with anatomical function and deviations associated with disease states. For example, The Parker Hypothesis (Parker, Phys. Med. Biol. 59: 4443,14) proposes that viscoelastic measures of soft tissue stiffness are related to the fractal branching properties of the vascular anatomy. Methods: Term human placentae were obtained immediately upon delivery and evaluated directly either in a 3T GE MRI with Elastography or using a Siemens Antares US scanner and VF10-5 Probe with custom single track location shear wave elasticity imaging pulse sequences and accelerated processing. Other placentae were perfused through the umbilical cord and imaging, Doppler measures and elastography were conducted. At the end of the experiments, a barium gel was infused to enhance subsequent CT imaging of the fetal vasculature. Results: The utility of elastography in functional evaluation of the placenta are readily demonstrated in the following examples: 1) Placental tissue anomalies (e.g., infarcted areas) are stiff, and provided dramatic examples of the sensitivity USE and MRE methodologies for the detection of placental pathology; 2) Ex vivo placental perfusions have been used to relate placental stiffness to fetal vasculature when measured by USE, as seen when fetal vascular dynamics were pharmacologically manipulated. Clinical and high-resolution microCT systems can and have been used on placentae to provide additional post-delivery anatomical characterization and quantification of the vascular beds. These CT observations provide confirmation of in vivo Doppler US and the potential use of MR angiography for vascular characterization. We demonstrated that these datasets are amenable to automated identification and characterization of branching morphology, including centerline tree and Sholl analyses. Conclusion: These USE and MRE technologies enable promising new approaches for the prediction of risks during and after pregnancy. (Support: Goode Foundation) MRI localization of a placental infarct with associated elastographic ortho slice A: gross examination of placental lesion. B, MR segmented volume. C. Superimposed MRE. Yellow arrow directs attention to lesion.