Investigation of intraplacental villous arteries by Doppler flow imaging in growth-restricted fetuses

OBJECTIVE: The purposes of our study were to assess the ability of color and power Doppler sonography to depict the blood flow in the intraplacental villous arteries and to evaluate whether the blood flow of intraplacental villous arteries in a normal pregnancy is different from that in a pregnancy that is associated with intrauterine growth restriction. STUDY DESIGN: Eighty-five women with uncomplicated pregnancy and 16 women with intrauterine growth-restricted fetuses between 27 and 38 weeks of gestation were examined by color and power Doppler imaging. The blood flow of intraplacental villous arteries was analyzed comparatively. The pulsatility index and peak systolic velocity were measured. RESULTS: A unit of 1 intraplacental villous artery-1 and its branches were seen as 1 cotyledon by color and power Doppler imaging. The cotyledon was easily identified and counted. Each cotyledon contained only 1 intraplacental villous artery-1. This method can visualize the intraplacental villous artery-1 to intraplacental villous artery-4 in normal pregnancies. The terminal villous arteries beyond intraplacental villous artery-4 were not imaged. The number of detectable intraplacental villous artery-1 in 1 placenta in intrauterine growth restriction was significantly lower than that in normal pregnancy. The number of detectable branches in intrauterine growth restriction was also significantly lower than in normal pregnancy. No intraplacental villous artery-4 blood flow was found in women with intrauterine growth restriction. In examined arteries, pulsatility index decreased and peak systolic velocity increased significantly with advancing gestational age (P <.02). At any given gestational age, pulsatility index and peak systolic velocity in the peripheral arteries were significantly lower than those in the upstream arteries in normal pregnancy (P <.001). The pulsatility index value of each intraplacental villous artery was also lower than that of the umbilical artery in the women with intrauterine growth restriction (P <.05). There were no differences in pulsatility index in each artery between the groups, although there were a few high pulsatility index values in intrauterine growth restriction. CONCLUSION: Color Doppler and power flow sonography are valuable tools for the detection of the blood flow of intraplacental villous arteries. The decrease in the number of detectable intraplacental villous artery-1 and branches was associated with intrauterine growth retardation.     

Relationship of utero- and fetoplacental blood flow velocity wave forms with pathomorphological placental findings.

Pulsed Doppler examinations were performed in 143 risk pregnancies. The resistance index (RI) values of the uteroplacental vessels and umbilical artery on the last examination before delivery were correlated to specific patterns of morphological placental findings. The sensitivity and specificity of Doppler blood flow velocity wave forms to predict placental disease as well as the significant relationships were calculated. Impaired uteroplacental perfusion is correlated with: disturbances in growth, such as reduced weight and reduced basal area (p < 0.005, p < 0.05); disturbances in villous maturation, such as prematurity or a reduction in intermediate sized villi (p < 0.05, p < 0.01), and circulation disorders, such as acute or chronic infarcts (p < 0.05), villous fibrosis (p < 0.005) or microfibrin deposits (p < 0.05). Villous immaturity was not correlated to either pathological utero- or fetoplacental blood flow. Except for acute infarcts, all these findings as well as endangiopathy of truncal arteries are also combined with high RI values in umbilical arteries (p < 0.005) possibly reflecting the 'down-stream impedance' of the fetoplacental circulation.     

Doppler velocimetry of intraplacental fetal arteries

Doppler velocimetry of the umbilical and intraplacental fetal arteries was studied by color flow mapping in 39 normal pregnancies. The systolic-diastolic ratio (S/D) and pulsatility index of the intraplacental fetal artery downstream to the umbilical artery decreased significantly with advancing gestational age, and its S/Ds were persistently lower than those of the umbilical artery. The difference in the S/D between the umbilical artery and its intraplacental downstream branches decreased with advancing gestational age and approached zero as the pregnancy progressed to term. We conclude that intraplacental fetal arteries, possibly fetal arteries in main stem villi, can be imaged by color flow mapping and that there is a significant "resistance gradient" between the intraplacental fetal artery and the umbilical artery. Intraplacental fetal artery velocimetry using color flow mapping may give further insights into the umbilical-placental circulation.     

用CDBFI技术检测恶性妊娠性滋养细胞肿瘤的子宫动脉血流阻力指数

目的：探讨恶性妊娠性滋养细胞肿瘤（ＭＧＴＴ）患者的子宫动脉血液动力学变化。方法：采用彩色多普勒血流显像（ＣＤＢＦＩ）技术测定了正常妇女２０例和ＭＧＴＴ３０例化疗前、后的子宫动脉血流阻力指数（ＲＩ）值。结果：化疗前ＭＧＴＴ组的子宫动脉ＲＩ值较正常组低（Ｐ＜０．０１），显示了ＭＧＴＴ子宫血流低阻特性；化疗有效者，经≥３个疗程化疗后子宫动脉ＲＩ值较化疗前明显增高（Ｐ＜０．０５）。结论：用ＣＤＢＦＩ技术检测子宫动脉血流参数有助于ＭＧＴＴ的诊断及观察化疗疗效。     

Evaluation of the utero-placental circulation by three-dimensional Doppler ultrasound in the second trimester of normal pregnancy.

OBJECTIVE: To define normative data with three-dimensional (3D) Doppler ultrasound in the second trimester spiral arteries and placental volume blood flow. METHODS: An entry criterion was a documented singleton pregnancy at 14-25 weeks with normal outcome. Each patient had a 3D power Doppler exam. Automatic volume acquisition of the placental and spiral arteries blood flow was obtained. We calculated vascularization index (VI), flow index (FI) and vascularization flow index (VFI). The patients were further divided into subgroups based on two gestational week intervals. The outcome measure was normal pregnancy outcome. RESULTS: One hundred ninety-nine patients were included in this study. Placental and spiral arteries vascular indices slowly increased indicating progressive development of vascular network and increase in the volume blood flow. The range for placental VI was 11.43-14.63, FI was 37.44-40 and VFI was 4.77-6.06. The range for spiral arteries VI was 19-20.91, FI was 39.66-41.1 and VFI was 8.49-8.92. The mean gestational age at delivery was 38.18 weeks. CONCLUSION: We defined normal 3D power Doppler vascular indices in pregnancies between 14 and 25 weeks of singleton gestation. The study indicated that placental and spiral arteries volume blood flow increased with the advancement of gestational age.     

Color flow mapping for myometrial invasion in women with a prior cesarean delivery

OBJECTIVES: Our aim was to evaluate the utility of color flow mapping in the prediction of placental myometrial invasion in women with Cesarean delivery. METHODS: Ultrasound color flow mapping was performed on placental implantations in potential proximity to the hysterotomy scar. The smallest myometrial thickness was measured under the placenta to evaluate the degree of myometrial attenuation in this area and note was made of unusual vascular lakes. RESULTS: Two hundred fifteen women with placentas in proximity to the prior hysterotomy scar underwent color Doppler mapping. Of 20 women with placenta previa and Cesarean delivery, 15 had Cesarean hysterectomy for bleeding complications and nine had the pathological diagnosis of placental invasion. The measurement of <1 mm for the smallest myometrial thickness or presence of large intraplacental lakes was predictive of myometrial invasion (sensitivity 100%, specificity 72%, PPPV 72%, and NPV 100%). CONCLUSIONS: Color flow mapping predicted myometrial invasion when the smallest myometrial thickness was <1 mm and large intraplacental lakes were demonstrated.     

Color flow mapping for myometrial invasion in women with a prior cesarean delivery

Objectives: Our aim was to evaluate the utility of color flow mapping in the prediction of placental myometrial invasion in women with Cesarean delivery.

Methods: Ultrasound color flow mapping was performed on placental implantations in potential proximity to the hysterotomy scar. The smallest myometrial thickness was measured under the placenta to evaluate the degree of myometrial attenuation in this area and note was made of unusual vascular lakes.

Results: Two hundred fifteen women with placentas in proximity to the prior hysterotomy scar underwent color Doppler mapping. Of 20 women with placenta previa and Cesarean delivery, 15 had Cesarean hysterectomy for bleeding complications and nine had the pathological diagnosis of placental invasion. The measurement of < 1 mm for the smallest myometrial thickness or presence of large intraplacental lakes was predictive of myometrial invasion (sensitivity 100%, specificity 72%, PPPV 72%, and NPV 100%).

Conclusions: Color flow mapping predicted myometrial invasion when the smallest myometrial thickness was < 1 mm and large intraplacental lakes were demonstrated.     

Doppler assessment of the fetoplacental circulation in normal and growth-retarded fetuses

The Pulsatility Index (PI) of Doppler flow signals from umbilical arteries was used to study flow resistance of the placental villous circulation. A preliminary reference curve of PI values in normal pregnancy was composed from 23 healthy women examined every 2 wk from the 16th postmenstrual week until delivery. The gestational age-related decrease of PI values reflects a reduction of flow resistance in the placental villous circulation. In small-for-date fetuses significantly increased PI values were found, indicating that this simple technique may permit an early diagnosis of compromised fetoplacental circulation, even several weeks to months before fetal growth retardation is clinically presumed.     

Doppler sonographic examinations of uteroplacental, fetoplacental, and fetal hemodynamics and their prognostic value in preterm labor.

Doppler examinations of different uteroplacental vessels (uterine arteries, arcuate arteries), umbilical artery, fetal thoracic aorta, and median cerebral artery were performed on 55 patients with idiopathic preterm labor (24.5 to 32.5 weeks). Thirty normal pregnancies of corresponding gestational age served as a control group. Significant differences of median values between the preterm labor and control group were found only for the resistance index (RI) in the central arcuate artery and for the pulsatility index (PI) in the fetal thoracic aorta. In about twenty percent of pregnancies in preterm labor, pathological values of RI and PI in uteroplacental and fetal vessels account for the presence of an impaired perfusion. Elevated PI in the uterine artery placental site and normal RI in the fetal thoracic aorta, correlate significantly to a shorter prolongation of pregnancy, lower gestational age on birth, and lower birth weight. The combination of these two blood flow indices (maternal PI greater than 0.90 and fetal RI less than 0.90) allow us to predict a preterm birth in a high percentage of cases (sensitivity 87.5%, specificity 100%, positive predictive value 100%, negative predictive value 93%).     

Color Doppler assessment of blood flow in endometrial cancer

OBJECTIVE: To determine the location and intensity of angiogenesis as well as selected flow parameters by transvaginal color Doppler (TVCD) and to evaluate the relation of myometrial invasion, histological grading, lymph nodes, and omental and adnexal metastasis on blood flow characteristics in endometrial cancer. METHODS: Transvaginal colour Doppler and pulsed Doppler ultrasound were performed on 90 women with endometrial cancer. The degree of invasion as well as adnexal, omental, and pelvic lymph node metastasis was evaluated. Location of the blood vessels (peripheral, central, mixed) and vascular density as well as selected Doppler blood flow indices: PSV, RI of neoplastic infiltration was assessed. RESULTS: The median age of the 90 women was 63.3 +/- 12.3 years (range 32 to 86 years); of these 92.2% were postmenopausal. Cancer concerned only the endometrium (E), with superficial (S) and deep infiltration (D) established in 14.4%, 45.6% and 40%, respectively. The histological maturity was as follows: G1 - 17.6%, G2 - 66.7%, G3 - 16.6% of cases. Adnexal, omental and lymph node metastasis was found in 12.2%, 3.3% and 16.6%, respectively. Abnormal low impedance and high velocity flow (mean RI 0.38 +/- 0.09, PSV 20.45 +/- 9.6 cm/sec) were found in 88.9% of cases. In types E, S, D in 61.5%, 92.7% and 94.4%, respectively (p = 0.003). Differences in RI and PSV between groups with high and low vascular density were statistically significant (p = 0.005 and 0.001, respectively). In all cases peripheral and mixed vascularity were found more frequently (p < 0.05). A positive significant correlation between vascular density increase and surgicopathological stage of cancer was found more frequently (p < 0.005). There were significant differences in vascular density, Doppler blood flow indices and vascular location in each type of histological malignancy (p < 0.05). No significant differences in each flow parameter in hematogenous-adnexal/omental metastatic and non metastatic cases were found, whereas pelvic lymph node involvement and vascular density were shown to be statistically significant (p < 0.02). There were significant differences in vascular density in lymph-node positive cases whereas the remaining flow parameters did not differ. CONCLUSIONS: These results suggest that TVCD evaluation of endometrial cancer is a reliable method for assessing endometrial angiogenesis. Our results indicate that blood flow rates correspond with increased angiogenesis in endometrial cancers, and might potentially be used as a good prediction factor for tumor progression and metastasis in affected women. Preoperative ultrasound examination should be seen as an important tool in the establishment of individualized treatment programs for women with endometrial cancer.     

Investigation of placental circulations by color Doppler ultrasonography

The placental circulations of 25 normal and five complicated pregnancies were studied by color Doppler ultrasonography. Flow velocity waveforms were obtained in all 30 pregnancies and could discriminate between fetal and maternal intraplacental blood flow. We believe that color Doppler ultrasonography will improve our understanding of the pathophysiology of various pregnancy disorders that alter the placental circulations and that color ultrasonography is useful for the prenatal differential diagnosis of intrauterine masses.     

Prognostic value of placental ultrasound in pregnancies complicated by absent end-diastolic flow velocity in the umbilical arteries

Our objective was to evaluate the utility of gray-scale placental ultrasound for the detection of pathological lesions in the placentas of preterm pregnancies with abnormal fetoplacental blood flow (defined by absent or reversed end-diastolic flow velocities [ARED] in the umbilical arteries) before 32 weeks of gestation. Sixty consecutive structurally and chromosomally normal singleton pregnancies were evaluated. Pre-defined criteria were used to describe placental appearances using gray-scale real-time ultrasound. Proximal uterine artery Doppler waveforms were recorded using pulsed and color Doppler ultrasound. Each patient had a thrombophilia profile. Following delivery, a single perinatal pathologist reviewed each placenta at a gross and microscopic level blinded to the placental ultrasound findings. Placental shape or texture was abnormal on gray-scale ultrasound in 43/59 (73%) and echogenic cystic lesions (ECL) were found in 16 (27%). Uterine artery Doppler was abnormal in 47/60 (78%) cases. Thirty-eight pregnancies were subsequently delivered by planned Caesarean section in the fetal and/or maternal interest (birthweights 540-2300 g, mean gestational age 30.6 weeks) and 21 pregnancies resulted in the vaginal delivery of a stillborn fetus where fetal weight and/or gestational age did not justify Caesarean section (birthweights 85-600 g, mean gestational age 24.9 weeks). ECL had a low positive predictive value for both villous infarcts (63%) and for focal/massive perivillous fibrin deposition (40%). Nevertheless, the combination of abnormal uterine artery Doppler and abnormal gray-scale findings (abnormal placental morphology or ECL) was strongly predictive of stillbirth (17/21; sensitivity 81%, PPV 52%, p = 0.006 Fisher's exact test). Pregnancies with ARED in the umbilical arteries have a high perinatal mortality associated with pathology of the placental villi. Ultrasound examination of the placenta and its maternal blood supply may contribute to the perinatal management of these pregnancies.     

脐动脉血流监测在产科的应用

脐动脉血流监测做为非侵入性的胎儿胎盘血流动力学评估方法,广泛应用于产科临床。脐动脉多普勒血流波形主要反映胎盘的血管阻力,受绒毛血管发育状况的影响。同时,胎龄、胎儿心率、胎儿呼吸和呃逆、胎动、脐带的采样位置、胎儿性别、胎盘重量及胎儿体重等也对其有一定的影响。循证医学证据推荐将脐动脉超声多普勒检测作为胎儿生长受限及双胎选择性生长受限的胎儿监测。在低危人群中,脐动脉血流监测的意义还存在很多争议。舒张末期血流缺失或反向与围产期结局显著不良相关,需注意排除胎儿先天性异常及非整倍体异常。脐动脉血流异常的产科处理取决于脐动脉多普勒检查结果异常的严重程度、基础产科并发症的严重程度以及孕周,应个体化处理。     

Uteroplacental Doppler flow velocity waveform indices in normal pregnancy: a statistical exercise and the development of appropriate reference values.

In a prospective cross-sectional study, we examined 154 normal pregnant women and measured the systolic to diastolic (S/D) ratio and resistance index (RI) in the umbilical artery and both uterine arteries. Placental location with respect to laterality was determined by real-time ultrasound. In patients with unilateral placental location, each uterine artery was evaluated according to its relationship with the placenta. Doppler flow velocity waveforms were obtained by a continuous wave Doppler device. Kolmogorov D tests revealed that RI values follow gaussian distribution, but that S/D values were markedly skewed to the right. There was a significant negative linear relationship between gestational age and umbilical artery RI and a significant negative curvilinear relationship between gestational age and umbilical artery (S/D (r = 0.83, p less than 0.001; and r = -0.79, p less than 0.001, respectively). Confidence bands for umbilical artery RI were developed based on the linear model with gestational age (fitted umbilical artery RI = 0.97199 - 0.01045*gestational age). Confidence bands for umbilical artery S/D were derived from the corresponding RI values by means of the functional relationship S/D = 1/(1 - RI). The RI and S/D values of the uterine arteries declined until 24 to 25 weeks' gestation and remained unchanged thereafter. This relationship, however, was not statistically significant (r = -0.10, p = 0.22). The placental uterine artery is different from the nonplacental quantitatively and qualitatively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Investigation of placental stem villi arteries in fetally growth-restricted pregnancies: a multivariate analysis

Thirteen placentas were studied from 5 normal pregnancies and 8 from pregnancies complicated by fetal growth restriction (4 with present, 3 with absent, and 1 with reversed end-diastolic velocities at Doppler interrogation of the umbilical arteries). On immunohistochemically stained slides, the diameter (d) and the wall thickness (t) of the arterial vasculature of the stem villi were measured for a total of approximately 10,000 vessels. A multivariate 'mixed effect model' statistical analysis was performed using d and t as dependent variables and gestational age, delivery mode, fetal and placental weight, the degree of vascular collapse and Doppler blood flow patterns as independent variables. Gestational age, Doppler pattern and the degree of vascular collapse significantly affected both d and t, the mode of delivery influenced d while fetal and placental weights scarcely affected the dependent variables. The above parameters should therefore be taken into account when investigating placental stem vessel morphometry.     

Uteroplacental hemodynamics during early human pregnancy: a longitudinal study

BACKGROUND: To determine normal physiologic changes in the uteroplacental hemodynamics during early placental development in the first trimester of pregnancy. METHODS: Sixteen normal singleton pregnancies were included in this longitudinal study. Transvaginal Doppler ultrasonographic examinations of uterine, arcuate, radial and spiral arteries were performed at the 5th, 7th, 8th and 10th completed gestational weeks. Peak systolic velocity (PSV), time-averaged maximum velocity (TAMXV) and the pulsatility index (PI) were measured. RESULTS: Uterine artery PSV, TAMXV and PI remained unchanged from the 5th to the 8th week of gestation. From the 8th to the 10th week, PSV (p = 0.02) and TAMXV (p = 0.005) increased and PI decreased (p = 0.006). Changes in the arcuate arteries were similar to those in uterine arteries. No significant changes in PSV, TAMXV or PI of the radial artery were noticed. Spiral artery PSV (p = 0.02) and TAMXV (p = 0.02) increased from the 5th to the 7th week. Thereafter they remained unchanged. Spiral artery PI decreased from the 5th to the 10th week, (p = 0.004). Throughout the study period, the PSV, TAMXV and PI values were significantly higher in the uterine artery than in the arcuate artery, and in the arcuate artery compared with the radial artery. At the 5th gestational week, no differences in PSV and TAMXV were found between radial and spiral arteries. From the 7th gestational week onwards, PSV and TAMXV were significantly lower in the radial artery than in the spiral artery. However, the PI values in the radial artery were significantly higher compared with those in the spiral artery during the whole study period. CONCLUSIONS: Spiral artery impedance decreases and blood flow velocities increase as early as between the 5th and the 7th weeks of gestation. During that period, the uterine and arcuate artery hemodynamics remain unchanged. In the uterine and arcuate arteries, decreases in impedance and increases in absolute velocities are detected after the 8th week of gestation. This delay between the changes in the spiral and uterine arteries may represent the magnitude of the increase of placental volume and spiral arterial involvement which is needed to affect uterine hemodynamics.     

Fetal microcirculation of abnormal human placenta. II. Scanning electron microscopy of placental vascular casts from fetus with severe erythroblastosis fetalis

The latex injection-corrosion cast technique coupled with scanning electron microscopy was applied to the study of severe Rh sensitization of the placenta. The main observed ultrastructural changes in fetal vasculature in this type of placenta were very similar to those of the small for gestational age placenta; large-sized vessels exhibited less branching than those of the normal placenta, and the capillary network showed numerous vascular buds and "H"-shaped anastomoses. In addition, in Rh-sensitized placentas, the capillary network was remarkably sparse, and the cast also revealed smooth-surfaced veins with distinct U shapes undulating through the placental stroma. These U-shaped veins may be the result of umbilical flow impedance with subsequent umbilical venous hypertension, which stretches the veins into undulating form.     

Doppler and immunohistochemical evaluation of decidual spiral arteries in early pregnancy

OBJECTIVE: The purpose of this study was to estimate spiral artery subchorionic flow at 8-11 gestational weeks (GW) by Doppler ultrasound and then to analyze these vessels in the decidua basalis using histologic, morphometric and immunohistochemical analyses. METHODS: Subchorionic spiral arteries were evaluated in 5 women scheduled for aspiration at 8-11 GW. Flow velocity waveforms were sought using color and pulsed Doppler, and the diastolic/systolic (D/S) index was calculated. Transcervical biopsy specimens and aspiration products were thoroughly examined to investigate the structure of the spiral artery at the implantation site using cytotrophoblastic and arterial smooth muscle cell immunohistochemical markers (anti-cytokeratin 7 and anti-actin monoclonal antibodies). Spiral artery cross-sectional inner areas were measured and compared with the D/S index in each case. RESULTS: Low-impedance pulsatile flow could be detected below the trophoblastic ring in all cases. Complete obstruction of a spiral artery lumen was never observed and cytotrophoblastic cells were incorporated into the vessel wall starting from the perivascular cuff. CONCLUSION: Both techniques evidenced that decidual spiral arteries in the placental bed are not completely obstructed at 8-11 GW.