Three-dimensional sonographic volume measurement of the fetal spleen

AIM: The objective of this longitudinal study was to evaluate the growth of the fetal spleen in normal pregnancies, using three-dimensional ultrasound. METHODS: Three-dimensional sonographic examinations were performed on 14 appropriate-for-gestational-age fetuses. Fetal splenic volume was measured every 2-3 weeks after 20 weeks of gestational age until delivery. RESULTS: Curvilinear relationships were found between the gestational age and splenic volume (R(2) = 80.2%, P < 0.0001), and normal ranges of splenic volume measurements for estimating the growth of the fetal spleen during normal pregnancy were generated. We found that the splenic volume calculation based on the equation for the volume of the ellipsoid by conventional two-dimensional ultrasound in previous investigations is about twice as large as that using three-dimensional ultrasound in our study, whereas the present data described in this study is quite comparable with previous data from an autopsy series. CONCLUSION: Our findings suggest that the standard curve for the fetal splenic volume using three-dimensional ultrasound provides a superior means for evaluating the normal splenic growth in the fetus and for identifying splenic abnormalities in utero. However, the data and its interpretation in our study should be taken with some degree of caution because of the small number of subjects studied. Further studies involving a larger sample size would be needed to confirm these findings.     

Three-Dimensional Ultrasonographic Assessments of Fetal Development

Objective: To visualize fetal surface anatomic structures in advancing gestation by use of three-dimensional ultrasonography with a specially developed abdominal three-dimensional transducer.Methods: One hundred six normal fetuses from 9 to 40 weeks’ gestation were studied with a specially developed abdominal three-dimensional transducer (3.5 MHz). This imaging system can provide conventional two-dimensional ultrasonography images and also can generate within seconds high-quality three-dimensional images in the surface and transparent modes with no need for an external workstation. We determined percentage of surface anatomic structures visualized at each trimester using two-dimensional and three-dimensional ultrasonography.Results: The number and the clarity of surface anatomic structures increased from the first to the third trimester of pregnancy. The image quality was less distinct in the first trimester because of the small fetal size. The ability to view the fetal face, hands, and feet was better with three-dimensional ultrasonography than with two-dimensional ultrasonography in the first trimester (P < .05), whereas fetal genitals were viewed better with two-dimensional ultrasonography than with three-dimensional ultrasonography in the second and third trimesters (P < .05).Conclusion: Three-dimensional ultrasonography provides a new means of visualizing surface anatomic structures of the fetus in utero. Our results suggest that three-dimensional ultrasonography has the potential to be a supplement to two-dimensional ultrasonography and should be useful in evaluating fetal abnormalities in high-risk pregnancies.     

Three-dimensional sonoembryology

Three-dimensional ultrasound plays an important role in obstetrics, predominantly for assessing fetal anatomy. The presentation of volume data in a standard anatomic orientation is valuable in order to assist both ultrasonographers and pregnant patients to recognize the anatomy more readily. Three-dimensional ultrasound is advantageous in studying 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 owing to the ability to obtain multiplanar images through endovaginal volume acquisition. Rotation of the embryo and close scrunity of the volume allow 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 thus evaluate their relationship to prediction of pregnancy outcome. Three-dimensional ultrasound imaging in vivo compliments pathological and histological evaluation of the developing embryo, giving rise to a new term: three-dimensional sonoembryology. Rapid technological development will allow real-time three-dimensional ultrasound to provide improved and expanded patient care on the one hand, and increased knowledge of developmental anatomy on the other.     

Correlation of prenatal ultrasound diagnosis and pathologic findings in fetuses with trisomy 13

OBJECTIVES: This study was conducted to compare the prenatal ultrasound findings and postmortem pathologic findings of fetuses with trisomy 13. METHODS: Of 22 150 fetal chromosome analyses, 28 fetuses with trisomy 13 were diagnosed between 1990 and 2004. Findings of second-trimester sonography and subsequent fetal autopsy were compared by organ system, and their correlation was assigned to one of three categories based on the degree of agreement. RESULTS: Of the total of 79 abnormalities that were found on autopsy, prenatal sonography showed 48 (60.8%). The agreement was more than 75% of all abnormalities of these systems: central nervous system (CNS) (76.5%), facial abnormalities (76.5%), urinary system (81.8%) and fetal hydrops (100%), whereas the sensitivity of sonography was lower in these organ systems: heart (53.3%), extremities (12.5%) and abdominal abnormalities (33.3%). In 39.2% of the cases, autopsy findings were not detected by sonography. These additional findings at autopsy involved mainly three organ systems: heart, face and extremities. Some ultrasound findings (n = 17) were not verified at autopsy; most of them were quantitative markers (mild ventriculomegaly, mild pyelectasis). CONCLUSION: Our results indicate that thorough sonographic examination of the fetal face (including ears) and extremities (including hands and feet) with an extensive use of fetal echocardiography may increase the sensitivity of prenatal sonography in detecting trisomy 13.     

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 structures, 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 defects. These data are useful not only for obstetricians but also for pediatricians and pediatric surgeons.     

Fetal weight prediction by thigh volume measurement with three-dimensional ultrasonography

OBJECTIVE: To evaluate the usefulness and accuracy of a simple method of predicting fetal weight by measuring fetal thigh volume with three-dimensional ultrasonography. METHODS: In 84 pregnant women, fetuses without structural or chromosomal anomalies were studied prospectively and cross-sectionally. Biparietal diameter (BPD), abdominal circumference (AC), and femur length (FL) were measured by two-dimensional ultrasound. Fetal thigh volume was measured by three-dimensional ultrasound, using three cross-sectional images of femur, from proximal, middle, and distal parts of femur diaphysis. Infants were delivered within 48 hours after ultrasound examinations. RESULTS: Modified thigh volume measurements using three cross-sectional images of femur by three-dimensional ultrasound were correlated strongly with birth weight (R(2) = 0.921, P <.001). Using linear and polynomial regression, we calculated a new best-fit formula: Birth weight (g) = 165.32 + 28.78 x modified thigh volume (mL). The mean and standard deviation of the residual were 121.8 and 110.4, respectively, in three-dimensional formulas, which were significantly smaller than those of two-dimensional formulas. CONCLUSION: Thigh volume measurement using three cross-sectional images of femur by three-dimensional ultrasound was simple, and there was better accuracy with this method than with two-dimensional ultrasound methods for predicting fetal weight during the third trimester of pregnancy.     

Three-dimensional sonoembryology

Three-dimensional (3D) ultrasound plays an important role in obstetrics, predominantly for assessing fetal anatomy. Presenting volume data in a standard anatomic orientation valuably assists both ultrasonographers and pregnant patients to recognize the anatomy more readily. Three-dimensional ultrasound is advantageous in studying 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 due to its ability to obtain multiplanar images through endovaginal volume acquisition. Rotation allows the systematic review of anatomic structures and early detection of fetal anomalies. Three-dimensional ultrasound imaging in vivo compliments pathologic and histologic evaluation of the developing embryo, giving rise to a new term: 3D sonoembryology. Rapid technological development will allow real-time 3D ultrasound to provide improved and expanded patient care on the one side, and increased knowledge of developmental anatomy on the other.     

Pregnancy Outcomes Following Sonographic Nonvisualization of the Fetal Stomach

Objective: To review pregnancy outcomes when two or more ultrasound scans persistently fail to visualize the fetal stomach.Methods: A computerized ultrasound database was used to identify all fetuses in which two or more serial ultrasound examinations failed to visualize the fetal stomach. Sonographic images were reviewed retrospectively, with the reviewer blinded to outcome data, to confirm persistent nonvisualization. Pregnancy outcome data were obtained from hospital charts and physicians’ office records. Fetal karyotypes, when performed, were obtained from amniotic fluid (AF) culture. The ultrasound findings then were compared with fetal karyotype results and pregnancy outcome data.Results: Of 35,569 ultrasound scans performed during 1991–1996, 26 fetuses (0.07%) with persistently nonvisualized stomachs were identified. Structural defects were detected in 17 fetuses (65%), most often involving the cardiothoracic (n = 5), genitourinary (n = 4), and central nervous systems (n = 4). Karyotypes were obtained in 12 fetuses, and four of them were abnormal. Only five of 17 fetuses (29%) with a structural defect survived. In nine of 26 fetuses (35%) with persistently nonvisualized stomachs, no structural defect was identified. Each of these nine fetuses had abnormal AF volume in its surrounding sac, and the overall perinatal survival in fetuses without a structural defect was only 50%.Conclusion: Fetuses with persistently nonvisualized stomachs have an increased incidence of structural defects and AF abnormalities and are more likely to have a poor outcome. A detailed ultrasound examination and fetal karyotype analysis should be performed to evaluate fetuses with persistently nonvisualized stomachs.     

Two- versus three-dimensional ultrasound in the second and third trimester of pregnancy: impact on recognition and maternal–fetal bonding. A prospective pilot study

Objective To assess the impact of three-dimensional (3D) versus two-dimensional (2D) ultrasound (US) on maternal–fetal bonding. Study design Prospective randomized pilot study among low risk women with singleton fetuses in the second and third trimester. Dependent on the randomization pattern, US was commenced either with 2D US or 3D US and the effects were recorded with standardized questionnaires. Results Sixty patients were included. Although the quality of 2D US, assessed by the examinator, was superior to 3D US, maternal recognition was higher with 3-D US (P = 0.004). With 2D US, nulliparous patients had significantly more difficulties visualizing the fetus, than multiparous (P = 0.03). However, the maternal preference of 3D US had no significant impact on maternal–fetal bonding. Conclusion Ultrasound had no significant effect on maternal–fetal bonding. Three-dimensional images may facilitate recognition of the fetus, but 3D US did not have higher impact on maternal–fetal bonding. This finding may be a reason not to consider 3D ultrasound for routine scanning.     

Comparison between ultrasound and magnetic resonance imaging in assessment of fetal cytomegalovirus infection

OBJECTIVE: To evaluate whether fetal brain magnetic resonance imaging (MRI) adds useful information to the one obtained by ultrasound in fetuses with cytomegalovirus (CMV) infection. METHODS: MRI and ultrasonographic findings were analyzed retrospectively in 38 fetuses with proven congenital CMV infection. Both techniques were performed on the same week at a mean gestational age of 33 weeks (24-37). The referral indications were maternal seroconversion (n = 19), and ultrasound findings (n = 19). The results were compared with the fetopathologic examination in cases with fetal death or termination of pregnancy (TOP) or the infant's neurological examination. RESULTS: The 38 cases were classified into three groups, depending on ultrasound findings at referral. Group 1: no ultrasound features (n = 11); group 2: extracerebral features without cerebral abnormalities at ultrasound (n = 13); group 3: presence of cerebral features at ultrasound (n = 14). In group 1, MRI was always normal. In group 2, MRI revealed cerebral features in six cases (46%). In group 3, MRI always confirmed the lesions seen at ultrasound and highlighted other cerebral features. CONCLUSIONS: MRI can provide important additional information with regard to abnormal gyration, cerebellar hypoplasia, or abnormal signal in white matter. It is certainly useful in the assessment of fetuses with extracerebral features without brain abnormalities detected with ultrasounds. If the fetal ultrasound is strictly normal in an infected fetus, MRI may not detect brain anomalies; however, it seems difficult to not perform this noninvasive procedure.     

Assessment of the blood flow in kidneys of growth-restricted fetuses using quantitative three-dimensional power Doppler ultrasound

Objective

Fetuses with fetal growth restrictions have higher perinatal mortality rates than fetuses without fetal growth restrictions. Vascularization of the fetal kidney is crucial to fetal growth. Hence, we assessed blood flow and vascularization of fetal kidneys in non-growth-restricted as well as growth-restricted fetuses using quantitative three-dimensional power Doppler ultrasound.

Can three-dimensional ultrasound be used for the assessment of the fetal lung volume in cases of congenital diaphragmatic hernia?

We report on 2 fetuses with congenital diaphragmatic hernia (CDH) in whom the fetal lung volumes were estimated by three-dimensional ultrasound and the results compared with the postmortem lung volume measurements. Both examiners (sonographer and pathologist) were blinded to each other's results. The 1st case was a right CDH diagnosed at 20 weeks of gestation. The 2nd case was a left CDH diagnosed at 22 weeks of gestation. Both pregnancies were terminated upon request of the parents. Three-dimensional ultrasound estimation of the fetal lung volume was performed 1 day before termination of pregnancy using the technique of rotation of the three perpendicular planes. The left and right lung volumes estimated by three-dimensional ultrasound were 3.88 and 1.87 cm(3), respectively, in the 1st case and 0 and 5.52 cm(3), respectively, in the 2nd case. On postmortem examination, the left and right lung volumes were 3.0 and 2.2 cm(3), respectively, in case 1 and 1.1 and 5.6 cm(3), respectively, in case 2. This suggests that a three-dimensional estimation of pulmonary volumes may be correlated with postmortem findings in cases with CDH.     

Fetal cardiac axis in non-anomalous pregnancies: does fetal gender or maternal body mass index (BMI) matter?

Objectives: To determine if cardiac axis obtained at an early ultrasound study (11–15 weeks) differs from that obtained at a late ultrasound study (18–22 weeks) in the same fetus and to evaluate the impact of fetal gender and/or maternal body mass index (BMI).

Methods: Cardiac axes of 324 non-anomalous fetuses at 11–15 weeks gestation were measured, with follow-up measurements obtained at 18–22 weeks. Comparisons were performed based on gestational age period, fetal gender and obese/non-obese maternal status.

Results: (1) Mean fetal cardiac axis did not change between 11 and 15 weeks; p?=?0.8, (2) mean fetal cardiac axis was more levorotated at 11–15 weeks than measurements obtained at 18–22 weeks; 48.1?±?7.1° versus 43.7?±?8.9°; p?<?0.0001, (3) male fetuses had less levorotated cardiac axis than female fetuses in late ultrasound studies but there was no difference between them at early ultrasound studies; 18–22 weeks male fetus, 42.7?±?9.3° versus female fetus, 45.2?±?8.3°; p?=?0.02 and 11–15 weeks male fetus, 48.1?±?7.0° versus female fetus, 48.4?±?7.4°, p?=?0.7, respectively, and (4) similar trends with the overall study population were observed in the comparison between fetuses of obese and non-obese women.

Conclusion: Fetal cardiac axis remains stable at 11–15 weeks, becoming less levorotated at 18–22 weeks. This may be attributed to increments in fetal lung volume. The differences in cardiac axis measurements between male and female fetuses examined at 18–22 weeks may also be attributable to differences in increment of fetal lung volume during this gestational age period.     

Transvaginal 3D and Doppler ultrasonography of the fetal brain

Transvaginal sonographic approach to the fetal brain, which provides detailed information about the fetal intracranial morphology, opened a new field in medicine, "neurosonography." The clinical significance of 3D ultrasound for prenatal diagnosis has been discussed since three-dimensional ultrasound was introduced in obstetrics. Three-dimensional ultrasound has several functions: surface reconstruction, multiplanar image analysis, three-dimensional sono-angiography, and volume calculation. In this article, we introduce transvaginal three-dimensional ultrasound for the assessment of fetal head and brain. Surface mode shows not only fetal head abnormality such as acrania but also normal cranial bones and sutures in the first trimester. Rotation of the brain volume image and multiplanar analysis enable tomographic visualization as magnetic resonance imaging. Sono-angiography shows the brain circulation three-dimensionally and extracted volume images of target organ provide information on detailed intracranial conditions. The technology is easy, noninvasive, and reproducible methods, and produces comprehensible and objective information.     

Assessment of cerebellar vermis biometry at 18–32 weeks of gestation by three-dimensional ultrasound examination

Objective: The purpose of this study was to construct reference limits for cerebellar vermis (CV) dimensions measured on images reconstructed from three-dimensional (3D) ultrasonography and to evaluate these measurements reproducibility. Methods: 3D ultrasound volumes were acquired transabdominally from an axial view of the fetal head in 342 fetuses cross-sectionally studied between 18 to 32 weeks of gestation. Offline analysis of fetal brain midsagittal plane was used to evaluate length and area of CV. The agreement between two-dimensional (2D) and 3D measurements as well as the interobserver variability in 3D measurements were assessed by interclass correlation coefficients (ICC). Results: Adequate visualization of the midsagittal plane was obtained in 96.7% of the fetuses. CV length (r?=?0.89, p?<?0.0001) and CV area (r?=?0.93, p?<?0.0001) showed a significant linear growth with gestation. A good agreement was found between measurements from either 2D or 3D ultrasound views (CV length ICC 0.943, CV area ICC 0.940) as well as between measured obtained by different observers (CV length ICC 0.965, CV area ICC 0.905). Conclusions: Measurements of the CV can be obtained from the midsagittal plane of fetal brain reconstructed from 3D volumes acquired transabdominally. The constructed nomograms may facilitate the diagnosis of cerebellar abnormalities.     

Demonstration of cranial sutures and fontanelles at 15 to 16 weeks of gestation: a comparison between two-dimensional and three-dimensional ultrasonography

OBJECTIVE: The purpose of this study was to evaluate the feasibility of obtaining good quality three-dimensional ultrasound pictures of the cranial sutures and fontanelles and to compare between two-dimensional and three-dimensional ultrasound in identifying the normal appearance of cranial sutures and fontanelles by the transvaginal approach at 15 to 16 weeks of gestation. METHODS: Fifty fetuses were prospectively evaluated by two-dimensional and three-dimensional transvaginal sonography between 15 and 16 weeks of gestation. The sagittal, coronal, lambdoidal, and metopic sutures, as well as anterior and posterior fontanelles, were inspected. RESULTS: Three-dimensional ultrasound enabled visualization of all sutures in 37 (74%) fetuses compared to 28 (56%) fetuses examined by two-dimensional ultrasonography (p = NS). The visualization of the sagittal suture was significantly superior by three-dimensional ultrasonography compared to two-dimensional ultrasonography (50 (100%) vs 35 (70%), p < 0.001). No significant difference between the two modalities was found in visualization of the fontanelles. CONCLUSION: Sutures and fontanelles are usually satisfactorily demonstrated by two-dimensional and three-dimensional ultrasound at 15 to 16 weeks of gestation. The sagittal suture is difficult to visualize using two-dimensional ultrasound, and three-dimensional ultrasound appears to be the best method for its demonstration.     

Fetal intracardiac potassium chloride injection to avoid the hopeless resuscitation of an abnormal abortus: I. Clinical issues.

OBJECTIVE: With the intention of preventing the attendant medical, ethical, and legal problems arising from the birth of live-born, anomalous fetuses, we initiated a program offering fetal intracardiac potassium chloride injection as an adjunctive measure in the setting of genetically indicated second-trimester abortion. METHODS: A lethal fetal injection was offered to patients carrying chromosomally or structurally abnormal fetuses at 19-24 weeks' gestation who desired abortion. When the patient elected this procedure, real-time ultrasound guidance was used to inject 3-5 mL of potassium chloride (2 mEq/mL) directly into the fetal cardiac chambers, followed by observation of fetal heart activity to ascertain cessation. Labor was subsequently induced with uterotonic prostaglandins. RESULTS: The procedure caused immediate cessation of fetal heart motion in 20 of 21 cases. There were no maternal complications. No fetuses were live-born. CONCLUSIONS: Direct fetal intracardiac potassium chloride injection effectively causes immediate fetal cardiac arrest. This approach may be adopted in cases of abortion by labor-induction methods at advanced gestations to ensure that the abortus is stillborn.     

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

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.     

Early detection of fetal abnormalities by three-dimensional sonography

The first generation of three-dimensional technology, during the early 1980s, provided a pseudo-three-dimensional image by the simultaneous display of the three orthogonal planes and offered some advantages over conventional two-dimensional imaging. Modern systems are capable of generating surface and transparent views depicting the sculpture-like reconstruction of fetal surface structures and transparent images of fetal inner anatomy. Three-dimensional scanning offers advantages in assessing embryonic morphology in the first trimester, owing to the ability to obtain multiplanar images through endovaginal volume acquisition. The three-dimensional possibility of rotation of the scanned object and close analysis of the scanned volume have allowed more systematic review of embryonic and extraembryonic anatomy. During the second and third trimesters, three-dimensional sonography provides a completely new way of visual perception of the unborn baby. Reconstructions and sculpture-like images, generated from surface rendering mode, are the most impressive presentations. Three-dimensional imaging of the fetal surface greatly refines and expands our capabilities in the evaluation of normal anatomy and in the detection of fetal anomalies. Fetal surface abnormalities can be selectively visualized, and the extent of a defect can be determined in all spatial dimensions.