Similar to ultrasound fetal morphological assessment during pregnancy, the placenta and umbilical cord should also be screened around the 20th week of gestation. Additionally, in pathologic conditions such as fetal growth restriction (FGR), preeclampsia, and various placental abnormalities, detail morphological and/or functional evaluations using Doppler methods are required. Superb microvascular imaging (SMI) is a new blood flow imaging technique that employs a unique algorithm to minimize motion artifacts by eliminating signals based on the analysis of tissue movement. While observing a placenta using SMI, dendritic blood flow from the umbilical cord indicating fetal blood flow can be seen on the background of scatter flow indicating maternal intervillous blood flow that beats in line with the mother\'s heartbeat. Using this modality, placental pathological findings can be obtained antenatally, especially histological findings of infarction and avascular villi. In the present review, SMI findings in the various pathologic placenta are demonstrated. These investigations may improve clinical practice in cases with placental abnormalities such as preeclampsia and FGR.
Goto M, Hasegawa J, Arakaki T, et al. Placenta previa with early opening of the uterine isthmus is associated with high risk of bleeding during pregnancy, and massive haemorrhage during caesarean delivery. Eur J Obstet Gynecol Reproduct Biol 2016;201:7–11. DOI: 10.1016/j.ejogrb.2016.03.012.
Hasegawa J, Kawabata I, Takeda Y, et al. Improving the accuracy of diagnosing placenta previa on transvaginal ultrasound by distinguishing between the uterine isthmus and cervix: a prospective multicenter observational study. Fetal Diagn Ther 2017;41(2):145–151. DOI: 10.1159/000446212.
Hasegawa J, Arakaki T, Ichizuka K, et al. Management of vasa previa during pregnancy. J Perinat Med 2015;43(6):783–784. DOI: 10.1515/jpm-2014-0047.
Hasegawa J. Ultrasound assessment of the umbilical cord. Donald School J Ultrasound Obstet Gynecol 2014;8(4):382–390. DOI: 10.5005/jp-journals-10009-1378.
Oyelese Y, Smulian JC. Placenta previa, placenta accreta, and vasa previa. Obstet Gynecol 2006;107(4):927–941. DOI: 10.1097/01.AOG.0000207559.15715.98.
Hasegawa J, Matsuoka R, Ichizuka K, et al. Velamentous cord insertion into the lower third of the uterus is associated with intrapartum fetal heart rate abnormalities. Ultrasound Obstet Gynecol 2006;27(4):425–429. DOI: 10.1002/uog.2645.
Furuya N, Sasaki T, Homma C, et al. Ultrasound screening and management of vasa previa in Japan. J Obstet Gynaecol Res 2020;46(7):1084–1089. DOI: 10.1111/jog.14254.
Hasegawa J. Ultrasound screening of umbilical cord abnormalities and delivery management. Placenta 2018;62:66–78. DOI: 10.1016/j.placenta.2017.12.003.
Morrow RJ, Adamson SL, Bull SB, et al. Acute hypoxemia does not affect the umbilical artery flow velocity waveform in fetal sheep. Obstet Gynecol 1990;75(4):590–593.
Turan OM, Turan S, Gungor S, et al. Progression of Doppler abnormalities in intrauterine growth restriction. Ultrasound Obstet Gynecol 2008;32(2):160–167. DOI: 10.1002/uog.5386.
Grannum PA, Berkowitz RL, Hobbins JC. The ultrasonic changes in the maturing placenta and their relation to fetal pulmonic maturity. Am J Obstet Gynecol 1979;133(8):915–922. DOI: 10.1016/0002-9378(79)90312-0.
Jauniaux E, Bhide A. Prenatal ultrasound diagnosis and outcome of placenta previa accreta after cesarean delivery: a systematic review and meta-analysis. Am J Obstet Gynecol 2017;217(1):27–36. DOI: 10.1016/j.ajog.2017.02.050.
Hasegawa J, Yamada H, Kawasaki E, et al. Application of superb micro-vascular imaging (SMI) in obstetrics. J Matern Fetal Neonatal Med 2018;31(2):261–263. DOI: 10.1080/14767058.2016.1278206.
Jiang ZZ, Huang YH, Shen HL, et al. Clinical applications of superb microvascular imaging in the liver, breast, thyroid, skeletal muscle, and carotid plaques. J Ultrasound Med 2019;38(11):2811–2820. DOI: 10.1002/jum.15008.
Furuya N, Hasegawa J, Homma C, et al. Novel ultrasound assessment of placental pathological function using superb microvascular imaging. J Matern Fetal Neonatal Med 2020. 1–4. DOI: 10.1080/14767058.2020.1795120.
Hasegawa J, Suzuki N. SMI for imaging of placental infarction. Placenta 2016;47:96–98. DOI: 10.1016/j.placenta.2016.08.092.
Hasegawa J, Kurasaki A, Hata T, et al. Diagnosis of placenta accreta spectrum using ultra-high-frequency probe and Superb microvascular Imaging. Ultrasound Obstet Gynecol 2019;54(5):705–707. DOI: 10.1002/uog.20207.
Hasegawa J. Sonoembryological evaluations of the development of placenta previa and velamentous cord insertion. J Obstet Gynaecol Res 2015;41(1):1–5. DOI: 10.1111/jog.12531.
Hasegawa J, Matsuoka R, Ichizuka K, et al. Predisposing factors for massive hemorrhage during cesarean section in patients with placenta previa. Ultrasound Obstet Gynecol 2009;34(1):80–84. DOI: 10.1002/uog.6426.
Saitoh M, Ishihara K, Sekiya T, et al. Anticipation of uterine bleeding in placenta previa based on vaginal sonographic evaluation. Gynecol Obstet Investigat 2002;54(1):37–42. DOI: 10.1159/000064695.
Al-Zirqi I, Vangen S, Forsen L, et al. Prevalence and risk factors of severe obstetric haemorrhage. BJOG 2008;115(10):1265–1272. DOI: 10.1111/j.1471-0528.2008.01859.x.
Glantz C, Purnell L. Clinical utility of sonography in the diagnosis and treatment of placental abruption. J Ultrasound Med 2002;21(8):837–840. DOI: 10.7863/jum.2002.21.8.837.
Redline RW. Clinical and pathological umbilical cord abnormalities in fetal thrombotic vasculopathy. Human Pathol 2004;35(12):1494–1498. DOI: 10.1016/j.humpath.2004.08.003.
Hasegawa J, Furuya N, Doi M, et al. Sono-embryological assessments of a true knot that developed into a hypercoiled cord and circumvallate placenta. J Matern Fetal Neonatal Med 2019. 1–5. DOI: 10.1080/14767058.2019.1704247.
Roberts JM, Hubel CA. The two stage model of preeclampsia: variations on the theme. Placenta 2009;30 Suppl A(Suppl A):S32–S37. DOI: 10.1016/j.placenta.2008.11.009.
Ernst LM. Maternal vascular malperfusion of the placental bed. APMIS 2018;126(7):551–560. DOI: 10.1111/apm.12833.