# Comparison of Laser Doppler Flowmetry With Contrast‐Enhanced Ultrasound to Approximate Placental Microvascular Blood Flow in the African Green Monkey (Chlorocebus aethiops sabaeus)

## TL;DR

This study compares two methods for measuring blood flow in monkey placentas and finds they give conflicting results.

## Contribution

Demonstrates lack of correlation between Laser Doppler Flowmetry and Contrast-Enhanced Ultrasound in placental perfusion measurements.

## Key findings

- No correlation found between LDF and CEUS measurements (Pearson r = -0.2026, p = 0.2431).
- LDF and CEUS produce discordant results for placental perfusion.
- LDF is unsuitable for heterogeneous organs like the placenta.

## Abstract

The ability to study in vivo microvascular flow within the placenta is limited. We sought to compare two techniques for evaluation of placental perfusion in a translational nonhuman primate model.

We measured placental microvascular perfusion in six pregnant African green monkeys (
Chlorocebus aethiops sabaeus) using both Laser Doppler Flowmetry (LDF) and contrast‐enhanced ultrasound (CEUS) in 2–4 discrete placental locations per animal at early‐ (EG), mid‐ (MG), and/or late‐gestation (LG). We assessed correlation between matched LDF and CEUS, with the hypothesis that we would observe concordance between these two measures of relative perfusion.

Using 35 total paired measurements (13 EG, n = 4; 12 MG, n = 4; 10 LG, n = 5), we found no correlation between LDF microvascular perfusion and CEUS microvascular flux rate (Pearson r = −0.2026, R
2 = 0.0411, p = 0.2431).

LDF and CEUS produce discordant results with respect to placental perfusion. LDF is ill‐suited to a heterogeneous organ such as the placenta.