The placenta is the conduit through which all fetal nourishment and oxygen delivery passes. Therefore, assessment of placental function is critical to understanding and monitoring the physiological state of the developing fetus. All nutrients and oxygen get to the fetus through placental communications between the maternal and fetal blood circulations. Hence, major factors for placental function are blood flow and perfusion. In this regard, we hypothesize that a new method for measuring umbilical arterial and venous flows can yield significant, new information about placental functional status. Since standard spectral Doppler studies can detect flow abnormalities related to IUGR, albeit generally late in gestation, we hypothesize that our new methods will be more sensitive to changes in placental function earlier than the present diagnostic techniques, including ultrasound Doppler measurements. We are expressing this optimism because we will use an angle-independent, flow profile independent volume flow measurement method, that we have validated in other settings, to make time-dependent blood flow measurements in the umbilical arteries and vein simultaneously. These will lead directly to a placental transfer function (PTF), which would be a totally benign method for analyzing placental function throughout gestation. If successful, our combined volume flow/transfer function methods can be quickly implemented on standard diagnostic ultrasound machines and moved into clinical use. Initially, we will use phantom studies to investigate how time-dependent umbilical cord flow is altered based on controlled changes in vascular resistance and compliance, and we will use this time-dependent flow information to create and validate a transfer function model of the phantom. In the phantom, we will have complete control of the flows, internal resistance/compliance, and pressure drops. We will be able to see how effectively the transfer function represents these parameters in the phantom. Once proven in phantoms, we will use a well-validated in-vivo pregnant sheep model of intrauterine growth restriction (IUGR), gestational testosterone treated sheep, to test how well flow and our transfer function model predict placental changes in IUGR.

Public Health Relevance

In this project, we will develop a 3D ultrasound-based method that uses the blood flow dynamics in the umbilical arteries and vein to quantitatively assess placental function. The technique is totally benign, can be applied throughout pregnancy, and has the potential to detect placental based abnormalities, such as intrauterine growth restriction (IUGR), earlier in gestation than standard ultrasound Doppler based methods.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21HD095501-01A1
Application #
9667174
Study Section
Medical Imaging Study Section (MEDI)
Program Officer
Weinberg, David H
Project Start
2019-02-14
Project End
2021-01-31
Budget Start
2019-02-14
Budget End
2020-01-31
Support Year
1
Fiscal Year
2019
Total Cost
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
073133571
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109