High sensitivity ultrasound microvessel imaging for the assessment of placental health.

Placental insufficiency underlies common and clinically challenging pregnancy complications including fetal growth restriction, preeclampsia, and preterm birth. Although these disorders share impaired placental function, current clinical tools cannot reliably detect early or subtle vascular abnormalities while pregnancy is ongoing. Standard obstetric ultrasound lacks the sensitivity needed to visualize small vessel development; however, high sensitivity microvessel imaging has emerged as a promising tool that overcomes many limitations of conventional Doppler ultrasound. By leveraging high frame rate or ultrafast ultrasound, together with advanced clutter filtering techniques, these highly sensitive ultrasound methods (often referred to as ultrafast Doppler or ultrasound microvessel imaging) can detect slow blood flow within small vessels that are invisible to conventional Doppler. The microvessel imaging has demonstrated promise in various clinical applications, such as assessing tumor vasculogenesis and autoimmune diseases. Only recently has microvessel imaging been applied to the placenta. Early studies show that it can visualize patterns of villous branching and vascular density that differ between healthy and complicated pregnancies. Some work has also linked microvessel imaging findings to placental pathology after delivery, suggesting the technique may allow clinicians to detect placental injury while pregnancy is ongoing. As the placenta cannot be directly assessed during gestation, a safe, non-invasive, and repeatable imaging tool is urgently needed. Ultrasound microvessel imaging has the potential to fill this gap by enabling earlier identification of at-risk pregnancies, improving monitoring and clinical decision-making throughout gestation.