Placental Sonolucencies



Placental Sonolucencies


Roya Sohaey, MD



DIFFERENTIAL DIAGNOSIS


Common



  • Placental Lake (PL)


  • Placental Abruption (PA)


  • Marginal Sinus Vessels


  • Tornado-Shaped Vessels of Accreta


Less Common



  • Placental Cord Insertion Cysts


  • Complete Hydatidiform Mole


  • Triploidy


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Obtain standard placenta views



    • Sagittal long views



      • Midsagittal to include lower uterine segment


      • Parasagittal


    • Axial views



      • Upper, mid, lower uterus


  • Use color Doppler in evaluating placental lesions



    • Marginal sinus vessels have flow but abruption does not



      • Both can present with retroplacental hypoechoic region


    • Placental lakes often have no discernible flow



      • Use real time grayscale findings to see swirling flow


      • Obtain cine clip if documentation of flow is important


  • Correlate placental findings with fetal findings



    • Fetal anomalies suggest triploidy


    • Intrauterine growth restriction suggests triploidy or placental insufficiency


Helpful Clues for Common Diagnoses



  • Placental Lake (PL)



    • Enlarged intervillous vascular spaces



      • Contain maternal blood


      • May have fluid/fluid level


    • Variable size


    • Transient nature



      • Change size and shape with time


      • Can completely resolve


    • Location



      • Within placenta without appreciable border


      • Subchorionic towards fetal surface


    • Occasional PL are normal



      • Late second trimester


      • Third trimester


    • Numerous PL or early PL associated with placental insufficiency



      • Intrauterine growth restriction (IUGR)


      • Oligohydramnios


      • High resistive umbilical artery flow


    • Power Doppler shows no flow in most PL



      • Swirling flow seen with real time scanning


    • Can thrombose and fibrose



      • Increased echogenicity


      • Discernible wall


      • No swirling flow seen


  • Placental Abruption (PA)



    • Marginal PA is most common



      • Hematoma has no blood flow


      • Placenta margin is lifted off uterus


      • Estimate how much placenta is detached


    • Retroplacental PA



      • May look like thick placenta when acute


      • Often presents with preterm labor not bleeding


    • Preplacental PA is rare



      • Blood in subchorionic/subamniotic space


      • May cause cord compromise if near cord insertion site


  • Marginal Sinus Vessels



    • Retroplacental sonolucency


    • Normal maternal venous vessels



      • Mostly myometrial veins


    • Doppler will often show flow


  • Tornado-Shaped Vessels of Accreta



    • Enlarged intraplacental lacunae


    • Triangle-shaped bizarre lucencies



      • Slow flow like with PL


    • Look for signs of accreta



      • Loss of myometrium


      • Invasion beyond uterine confines: Scan with full bladder to look for invasion


      • Use color Doppler to evaluate for vascular flow


    • MR may help with diagnosis


Helpful Clues for Less Common Diagnoses

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Aug 10, 2016 | Posted by in OBSTETRICS | Comments Off on Placental Sonolucencies

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