Comparison of Umbilical and Uterine Artery Doppler Indices with Placental Shear Wave Elastography and Superb Microvascular Imaging Findings in Pregnancies Beyond 20 Weeks: A Retrospective Study

Q: What is the clinical evidence from this study?

Study design: Observational. Population: Pregnancy beyond 20 weeks (placental assessment) (n=66). Intervention: Placental shear wave elastography (SWE) and superb microvascular imaging (SMI) vs. Conventional uterine and umbilical artery Doppler ultrasonography indices. Primary outcome: Correlation between umbilical artery pulsatility index (PI) and central placental SMI vascular index (r = -0.409, p=0.002).

Tayfun Akay; Naile Bolca Topal; Başak Erdemli Gürsel; Erdal Karavaş; Eren Tobcu; Özge Tanışman

doi:10.4274/advradiolimaging.galenos.2026.77528

September 30, 2026Advanced radiology and imaging.Open Access

Comparison of Umbilical and Uterine Artery Doppler Indices with Placental Shear Wave Elastography and Superb Microvascular Imaging Findings in Pregnancies Beyond 20 Weeks: A Retrospective Study

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Key result

Placental superb microvascular imaging vascular index inversely correlates with umbilical and uterine artery Doppler indices.

r = -0.409
P=0.002
n=66

Why the study?

Conventional obstetric Doppler ultrasonography provides limited information on placental morphology and microvascular alterations, and the relationship between Doppler indices and newer non-invasive ultrasound techniques such as shear wave elastography (SWE) and superb microvascular imaging (SMI) required investigation.

Does placental shear wave elastography (SWE) and superb microvascular imaging (SMI) correlate with conventional uterine and umbilical artery Doppler indices in pregnant women beyond 20 weeks of gestation?

Key Points

To evaluate the relationship between maternal and fetal Doppler indices and placental tissue stiffness and microvascular architecture measured by shear wave elastography and superb microvascular imaging.
Retrospective study analyzing 66 pregnant women aged ≥18 years at ≥20 weeks of gestation (median 22.21 weeks) with anterior or anterolateral placental localization.
Placental stiffness was measured in kilopascals using shear wave elastography (SWE), and vascular index percentages were determined using superb microvascular imaging (SMI) in central and peripheral placental zones alongside umbilical and uterine artery Doppler parameters.
Umbilical artery pulsatility index showed significant negative correlations with central SMI (r=-0.409, p=0.002) and peripheral SMI (r=-0.375, p=0.005), whereas SWE measurements showed no significant correlation with Doppler indices.
Right uterine artery resistance index was significantly negatively correlated with central SMI (r=-0.273, p=0.046) and peripheral SMI (r=-0.330, p=0.015), while left uterine artery resistance index was negatively correlated with peripheral SMI (r=-0.396, p=0.003).
Central SWE (p=0.049) and peripheral SMI (p=0.028) differed significantly between obese and non-obese participants, and subcutaneous adipose tissue thickness significantly affected both central (p=0.027) and peripheral SMI (p=0.012).

Study Design

Type

Observational (n=66)

Multicenter

No

Structured PICO

Does placental shear wave elastography (SWE) and superb microvascular imaging (SMI) correlate with conventional uterine and umbilical artery Doppler indices in pregnant women beyond 20 weeks of gestation?

P

Population

66 pregnant women aged 18-46 years at >=20 weeks of gestation with singleton pregnancies and anterior placental localization undergoing retrospective multimodal placental ultrasound evaluation.

E

Exposure

Multimodal placental ultrasonographic evaluation including grayscale ultrasonography, obstetric Doppler ultrasonography (bilateral uterine artery and umbilical artery PI and RI), placental shear wave elastography (SWE in kPa from central and peripheral regions), and superb microvascular imaging (SMI vascular index % from central and peripheral regions) performed in the supine position.

O

Outcome

Correlation between conventional obstetric Doppler indices (uterine and umbilical artery PI and RI) and placental SWE (stiffness in kPa) and SMI (vascular index in %) measurements in central and peripheral placental regions.surrogate

Main Result

Effect estimate: r = -0.409

p-value: p=0.002

Placental superb microvascular imaging (SMI) correlates negatively with uterine and umbilical artery Doppler resistance indices, suggesting it may detect microvascular alterations in placental insufficiency earlier than stiffness changes measured by shear wave elastography.

Limitations

Retrospective single-center design limiting causal interpretation
Relatively small number of pregnant women with comorbid conditions
Reduced ultrasound penetration and sensitivity of the high-frequency linear transducer for SMI in patients with excessive subcutaneous adipose tissue thickness (>=20 mm)
Exclusion of posteriorly located and deeply seated placentas due to suboptimal ultrasonographic assessment
Retrospective single-center design inherently limits causal interpretation
High-frequency linear transducer used for SMI examinations reduced image penetration and sensitivity in patients with excessive subcutaneous adipose tissue thickness or deeply located placentas
Posteriorly located and deeply seated placentas were excluded because optimal ultrasonographic assessment could not be achieved

Implication

Should not yet alter obstetric Doppler protocols; leaves open superb microvascular imaging utility in prospective placental studies.

Abstract

Objectives: Placental insufficiency is closely associated with alterations in the uterine and umbilical artery (UA) waveforms, which are considered early indicators of impaired placental function and underscore the clinical importance of obstetric Doppler ultrasonography.However, conventional Doppler ultrasonography provides limited information regarding placental morphology and microvascular alterations.Recent advances in ultrasound technology have introduced shear wave elastography (SWE) and superb microvascular imaging (SMI) as promising non-invasive techniques for assessing placental stiffness and microvascular architecture.This study aimed to investigate the relationship between obstetric Doppler indices and placental SWE and SMI measurements.Methods: This retrospective study included 66 pregnant women aged ≥18 years with gestational age ≥20 weeks and anterior placental localization.Placental stiffness (kilopascals) was measured using SWE, while the vascular index (%) was obtained using SMI from both central and peripheral placental regions.The associations between Doppler indices and imaging parameters were analyzed.Results: Significant negative correlations were identified between uterine and UA Doppler indices and placental SMI measurements obtained from both central and peripheral regions.In addition, significant differences were observed in central SMI (p=0.027) and peripheral SMI (p=0.012) according to subcutaneous adipose tissue thickness.Comparisons between obese and non-obese pregnant women also demonstrated significant differences in central SWE measurements (p=0.049) and peripheral SMI values (p=0.028).Conclusion: These findings suggest that multimodal ultrasonographic evaluation combining grayscale ultrasonography, SWE, SMI, and conventional Doppler ultrasonography may improve placental assessment and contribute to better clinical management of placental insufficiency.Furthermore, SMI may detect placental microvascular alterations earlier than measurable stiffness changes identified by SWE.

Discussion

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Cite This Study

Akay et al. (2026) conducted an observational in Pregnancy beyond 20 weeks (placental assessment) (n=66). Placental shear wave elastography (SWE) and superb microvascular imaging (SMI) vs. Conventional uterine and umbilical artery Doppler ultrasonography indices was evaluated on Correlation between umbilical artery pulsatility index (PI) and central placental SMI vascular index (r = -0.409, p=0.002). Placental superb microvascular imaging vascular index correlated negatively with umbilical artery PI (r=-0.409, p=0.002) and uterine artery Doppler indices, whereas shear wave elastography did not.

synapsesocial.com/papers/6ae28dedcbadf70daf6c3f6d https://doi.org/10.4274/advradiolimaging.galenos.2026.77528

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Comparison of Umbilical and Uterine Artery Doppler Indices with Placental Shear Wave Elastography and Superb Microvascular Imaging Findings in Pregnancies Beyond 20 Weeks: A Retrospective Study

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

Comparison of Umbilical and Uterine Artery Doppler Indices with Placental Shear Wave Elastography and Superb Microvascular Imaging Findings in Pregnancies Beyond 20 Weeks: A Retrospective Study

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

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