Acoustic radiation force impulse elastosonography of placenta in maternal red blood cell alloimmunization: a preliminary and descriptive study

Abstract

Aims: Maternal red blood cell alloimmunization is an important cause of fetal morbidity and mortality in the perinatal period, despite well-organized prophylaxis programs. The objective of the study was to evaluate placental elasticity by using Acoustic Radiation Force Impulse (ARFI) in Rhesus (Rh) alloimmunized pregnant women with hydropic and nonhydropic fetuses and to compare those with healthy pregnant women. Material and methods: This case-control and descriptive study comprised twenty-eight healthy pregnant women, 14 Rh alloimmunized pregnant women with nonhydropic fetuses, and 16 Rh alloimmunized pregnant women with hydropic fetuses in the third trimester of pregnancy. Placental elasticity measurements were performed by ARFI elastosonography at the day of delivery. The maternal characteristics and neonatal outcomes of the patients were also noted. Results: The highest mean placental ARFI scores were observed in Rh alloimmunized pregnant women with hydropic fetuses (1.13 m/s) (p=0.001). Healthy controls and Rh alloimmunized pregnant women with nonhydropic fetuses had similar mean placenta ARFI scores (0.84 m/s, 0.88 m/s, respectively) (p<0.05). Conclusions: Based on the present findings, the placenta becomes stiffer in Rh alloimmunized pregnancies complicated with hydrops fetalis. The increased placental ARFI scores may be a supplemental marker for adverse pregnancy outcomes, additional to Doppler evaluation of middle cerebral artery. This data should be confirmed with a large sample size and prospective studies by using serial measurements of ARFI elastosonography in maternal red blood cell alloimmunization.

Comparison of fetal and maternal tissue elasticity between euploid and aneuploid pregnancies by shear wave elastography

“…[11][12][13] A limited number of human studies include healthy pregnancies, pregnancies with hypertensive disorders, and fetal abnormalities, investigating the elasticity of the placenta, fetal lungs, liver, brain, and myocardium. [14][15][16][17][18][19][20] As far as we know, our study is the first elastography research on both healthy pregnancies and pregnancies with chromosomal abnormalities including placenta, maternal myometrium, and tissues used in the genetic sonogram. Unfortunately, this study took place during the COVID-19 pandemic outbreak, where the referring number of patients was considerably decreased.…”

“…In the literature, research is reported on the fetomaternal elastographic evaluation of dogs, sheep, and baboons 11–13 . A limited number of human studies include healthy pregnancies, pregnancies with hypertensive disorders, and fetal abnormalities, investigating the elasticity of the placenta, fetal lungs, liver, brain, and myocardium 14–20 . As far as we know, our study is the first elastography research on both healthy pregnancies and pregnancies with chromosomal abnormalities including placenta, maternal myometrium, and tissues used in the genetic sonogram.…”

Shear-wave elastography for detection of placenta percreta: a case-controlled study

“…SWE is a promising technique that is used to measure tissue stiffness in vivo. Placental stiffness in a healthy pregnancy or pregnancies accompanied by various pathologies has been studied in recent years (15,16,18,19). In the present study, the mean SWV was 1.69 AE 0.23 m/s in the control group, which was a higher value than the mean velocity values of previous studies, such as by Ohmaru et al (20) with a mean value of 0.98 AE 0.21 m/s, and by Wu et al (19) with a mean value of 0.98 AE 0.26 m/s in healthy pregnancies.…”

“…Although stiffness was measured only from the maternal edge, studies have shown similar values in any region of the normal placenta indicating that SWE values from any region could be used for the overall stiffness of the placenta (24,25). Increased placental stiffness has been reported in many pathologies such as pre-eclampsia, Rh alloimmunized pregnant women with hydropic fetuses, or pregnancies with fetal anomalies, possibly due to some histopathological changes in the placenta (15,16,25). Sugitani et al (10) performed histopathological examinations on placentas showing increased SWV values and found widespread infarction and inflammation.…”

“…Although the safety of SWE in the developing fetus has not been fully established because of the high energy of this modality, recent studies showed that SWE has no potential risk (thermal or chemical) to the placenta and fetus (7–10). Therefore, there has been much recent work on placental elastography in pregnant women with pre-eclampsia, gestational diabetes, preterm delivery, fetal abnormalities, fetal growth restriction, and alloimmunization (11–16). In addition, this method has shown that abnormal structural changes affect placental stiffness in placenta previa (17).…”