Milan Kos

The study of morphology and circulation of early embryo by three-dimensional ultrasound and power Doppler

Abstract Three-dimensional (3-D) ultrasound plays an important role in obstetrics predominantly for assessing fetal anatomy. Presenting volume data in a standard anatomic orientation assists both ultrasonographers and pregnant patients to recognize anatomy more readily. Three-dimensional ultrasound is advantageous for the study of normal embryonic and/or fetal development, as well as providing information for families at risk for specific congenital anomalies by confirming normality. This method offers advantages in assessing the embryo in the first trimester as it is able to obtain multiplanar images through endovaginal volume acquisition. Rotation of the embryo and close scrutiny of the volume allow the systematic review of anatomic structures such as cord insertion, limb buds, cerebral cavities, stomach and bladder. Using this modality one can easily obtain the volumes of the gestational sac and yolk sac and can evaluate their relationship to prediction of pregnancy outcome. Three-dimensional power Doppler sonography has the potential to study process of placentation and evaluate the development of the embryonic and fetal cardiovascular systems. Three-dimensional ultrasound imaging in vivo compliments pathologic and histologic evaluation of the developing embryo, giving rise to a new term: 3-D sonoembryology. Rapid technological development will allow real-time 3-D ultrasound to provide improved and expanded patient care on the one side, and increased knowledge of developmental anatomy on the another.

Fetal cerebrovascular response to chronic hypoxia—implications for the prevention of brain damage

Fetal hypoxia is one of the leading causes of perinatal morbidity and mortality. One of the most severe sequels of fetal hypoxic insult is the development of perinatal brain lesions resulting in a spectrum of neurological disabilities, from minor cerebral disorders to cerebral palsy. One of the most important fetal adaptive responses to hypoxia is redistribution of blood flow towards the fetal brain, known as the ‘brain sparing effect’. The fetal blood flow redistribution in favor of the fetal brain can be detected and quantified by the Doppler cerebral/umbilical ratio (C/U ratio = cerebral resistance index (CRI)/umbilical resistance index (URI)). Our studies on animal models and human fetuses have demonstrated clearly that this phenomenon cannot prevent the development of perinatal brain lesions in the case of severe or prolonged hypoxia. Fetal deterioration in chronic and severe hypoxia is characterized by the disappearance of the physiological cerebral vascular variability (vasoconstriction and vasodilatation), followed by an increase in cerebral vascular resistance. However, our latest study on growth-restricted and hypoxic human fetuses has shown that perinatal brain lesions can develop even before the loss of cerebrovascular variability. The fetal exposure to hypoxia can be quantified by using a new vascular score, the hypoxia index. This parameter, which takes into account the degree as well as duration of fetal hypoxia, can be calculated by summing the daily % C/U ratio reduction from the cut-off value 1 over the period of observation. According to our results, the use of this parameter, which calculates the cumulative, relative oxygen deficit, could allow for the first time the sensitive and reliable prediction and even prevention of adverse neurological outcome in pregnancies complicated by fetal hypoxia.

Correlation of Confined Placental Mosaicism with Fetal Intrauterine Growth Retardation

Objective: Our purpose was to determine if the frequency of confined placental mosaicism in newborns with unexplained intrauterine growth retardation (IUGR) was higher compared with infants with appropriate growth in utero and the outcome of these pregnancies. Study Design: A total of 20 cases with unexplained IUGR and 20 cases with appropriate growth for gestational age has been studied. Amnion, chorion and villi biopsy specimens were obtained from growth-retarded cases and controls at delivery. Cord blood specimens for 48-hour lymphocyte cultures were obtained from all infants with IUGR. Results: Karyotype analysis revealed confined placental mosaicism in two of 20 (10%) cases with IUGR. In one growth retarded case and one appropriate growth for gestational age case, mosaicism was also confirmed in the amnion. Cytogenetic analysis from peripheral blood of newborns showed normal karyotype in all cases. Three pregnancies in the group of fetuses with IUGR (15%) ended with fetal death compared with normal fetal surveillance of all cases from the control group. Conclusion: Confined placental mosaicism was detected two times more frequently from placentas of growth- retarded infants compared with those of newborns with appropriate growth. The fetal loss was significantly higher in the group of cases with IUGR compared with the control group.

Intervillous circulation in all three trimesters of normal pregnancy assessed by color Doppler

Our cross-sectional study included 115 healthy pregnant women in gestational age between 7 and 24 weeks. The aim of the study was to compare resistance (RI) and pulsatility (PI) indices, peak systolic velocity (PSV), end-diastolic velocity, and temporal averaged maximum velocity (TAMV) of the spiral arteries and vessels within the intervillous space in all three trimesters of pregnancy. The impedance to blood flow within the intervillous space significantly decreased towards the mid-pregnancy (p < 0.01) and then remained stable. Blood flow velocities within the intervillous space expressed by PSV, EDV and TAMV increased significantly (p < 0.01) towards the mid-pregnancy. After reaching the plateau between 16 and 22 weeks of gestation, these parameters remained almost constant until the 36th gestational week. Near the term low-significant decrease of blood flow velocities was noted: for PSV and TAMV p < 0.07, and for EDV p < 0.05. A significant increase in continuous intervillous blood flow velocity was noted from the 11th week onward (28 +/- 12 vs. 36 +/- 12) until the 36th week of gestation (36 +/- 12 cm/s). The first report of the haemodynamic changes within the intervillous space during pregnancy may have implication in better understanding of the metabolical interchange between maternal and fetal side.

Three-dimensional sonography in prenatal diagnosis : a luxury or a necessity ?

Abstract Three-dimensional sonography revolutionized ultrasound imaging with its capacity to depict an unlimited number of planes in which the object of interest can be displayed. The addition of numerous modalities of image rendering promotes three-dimensional sonography to the top of the spectrum of diagnostic imaging in obstetrics and gynecology. The aim of this article is to present our experience in 3-D sonography during the second and third trimester of pregnancy and to give a comparative review of literature. 247 patients in gestational age ranging from 12 to 40 weeks of gestation were examined over a three year period. The majority of patients entered the study because fetal anomaly was suspected at two-dimensional sonography. Some patients were sent on to three-dimensional sonography because it was not possible to depict clearly normal fetal anatomy by two dimensional sonography. Out of 170 fetal anomalies three-dimensional sonographic analysis failed in only three cases. In all three anomaly was accompanied with severe oligohydramnios. Main advantages of three-dimensional ultrasound in perinatal medicine and antenatal diagnosis include scanning in the coronal plane, improved assessment of complex anatomic structures, surface analysis of minor defects, volumetric measuring of organs, “plastic” transparent imaging of fetal skeleton, spatial presentation of blood flow arborization and, finally, storage of scanned volumes and images. It is our decided opinion that three-dimensional sonography has gained a valuable place in prenatal diagnosis, becoming a necessity for every modern perinatal unit.

Limb deformities and three-dimensional ultrasound

Abstract Aim: To assess the ability of three-dimensional (3D) ultrasonography for improvement of antenatal detection of limb deformities. Methods: 347 patients were selected from a routine outpatient clinic or sent for supervision from other units because of suspected anomalies of fetal extremities. 3D ultrasound devices used in the study were Combison 530D and Voluson 530D MT (Kretztechnik, Zipf, Austria) with a 3–5 MHz annular array transducer for three-dimensional volume scanning. Results: In 41 of 347 patients the initial diagnosis was suspected by two-dimensional sonography (gestational age 18–32 weeks). In 28 of 41 suspected cases the diagnosis of abnormalities was determined after examination by 3D sonography: 17/28 clubfoot, 3/28 hand-polydactily, 2/28 upper limb contractures, 1/28 lower limb contractures, 4/28 micromelia within the syndrome of skeletal dysplasia. In 13 of 41 suspected cases, normal anatomy was confirmed using 3D sonography. Conclusion: Three-dimensional sonography is the “method of choice” for the detection of an isolated defect of a single limb, developmental or positional deformations and minor defects of hands and feet. Surface-mode reconstruction of the complete limb and transparent-view reconstruction of the entire skeletal structure are effective technical advantages enabling a completely new visual perception of the unborn baby.

Subchorionic Hematomas in Early Pregnancy: Clinical Outcome and Blood Flow Patterns

A case control study of 59 women with subchorionic hematomas compared to 135 normally pregnant. Transvaginal ultrasound was used to image the pregnancy, and identify the site and size of the hematomas. Color flow Doppler was used to calculate velocity indices of the spiral arteries. More spontaneous abortions occurred in women with subchorionic hematomas (SCH). There was general correlation between gestational age, velocity indices, and hematoma size. There were 10 spontaneous abortions in the study group (17%) versus 9 (6.5%) in the controls (P = 0.02). Hematoma size did not affect outcome, but site did. Most hematomas associated with abortion were found in the corpus or fundus of the uterus, not in the supracervical area (P = 0.03). The presence of a hematoma did not affect the frequency of preterm delivery. In conclusion, subchorionic hematomas in early pregnancy are associated with an increased risk of spontaneous abortion. Flow disturbances are seen in the spiral arteries, but these are probably secondary effects. The critical factor is site of hematoma, not volume.

Doppler information pertaining to the intrapartum period

The aim of the study was to evaluate the use of color-Doppler velocimetry during the labor. 325 intrapartal measurements of the umbilical artery, fetal aorta, middle cerebral artery and arcuate arteries were performed in a group of 105 patients. The resistance index (RI) and pulsatility index (PI) were measured. During the active labor the RI and PI of the umbilical artery remained unchanged. The impedance in arcuate arteries have increased (p < 0.05). The RI and PI of the middle cerebral artery showed non significantly increased mean values when compared with the corresponding values during pregnancy. But, a short term, transitory decreased impedance is registered during the decrement slope of contraction. Since fetal outcome was normal in all newborns, these changes are considered as physiologic.

Three-Dimensional Sonography for Assessment of Morphology and Vascularization of the Fetus and Placenta:

Objective: To analyze the potential of three-dimensional power Doppler sonography in morphologic and functional assessment of the fetus and placenta. Methods: Review of the recent literature on three-dimensional sonography in early pregnancy and in the second and third trimester. Results: Three-dimensional sonography plays an important role in obstetrics predominantly for assessing fetal anatomy. Multiplanar images and rotation of the object allow systematic review of anatomic structure, such as limb buds, cerebral cavities, cord insertion, stomach, and bladder. Using this modality, volumes of the gestational sac, yolk sac, and fetal organs can be obtained easily. Three-dimensional power Doppler sonography has the potential to study the intervillous and placental circulation and evaluate the development of the embryonic and fetal cardiovascular system. Conclusions: Three-dimensional ultrasound imaging complements pathologic and histologic evaluation of the developing embryo, giving rise to the new term “three-dimensional sonoembryology.” It is evident that three-dimensional ultrasonography improves the visualization of the normal and abnormal fetal anatomy giving a realistic impression of the extent of the defect. These data are useful not only for obstetricians but also for pediatricians and pediatric surgeons.

Incidence of chromosomopathies and cystic fibrosis mutations in second trimester fetuses with isolated hyperechoic bowel

OBJECTIVE Fetal echoic bowel can be a normal second trimester ultrasonographic finding which usually disappears by 20 weeks on serial sonograms. Recent studies have suggested a possible association of hyperechoic fetal bowel with chromosomopathies and cystic fibrosis. The aim of our study is to determine the incidence of chromosomopathies and cystic fibrosis mutations among the fetuses with isolated hyperechoic bowel. METHODS Sixteen fetuses with isolated echoic bowel were detected: 13 fetuses < or =20 weeks gestation (group I) and 3 fetuses at 20-26 weeks gestation (group II). Cytogenetic studies were performed in all 16 cases and 11 families had deoxyribonucleic acid-based risk assessment for cystic fibrosis. The echogenity of bowel was that of surrounding bone. RESULTS Two cases of trisomy 21 and 1 case of trisomy 13 were detected (18.7%). The other ultrasonographic markers begin to appear after 21 weeks gestation in fetuses with trisomy 13. Two of 3 pregnant women with pathological karyotype were younger than 35 years. One of 11 cases (9%) was found to be a heterozygote carrier for deltaF508 mutation. CONCLUSIONS Isolated hyperechoic bowel in the second trimester was found to be associated with a significantly higher risk of fetal aneuploidy.