Prenatal diagnosis of truncus arteriosus using multiplanar display in 4D ultrasonography

Abstract

Prenatal diagnosis of truncus arteriosus with two-dimensional sonography requires expertise in fetal echocardiography. Indeed, truncus arteriosus shares with tetralogy of Fallot and pulmonary atresia with a ventricular septal defect (VSD) the sonographic finding of a single arterial trunk overriding a VSD. The diagnosis of truncus arteriosus can be confirmed when either the main pulmonary artery or its branches are visualized arising from the truncus itself. This requires sequential examination of multiple scanning planes and a process of mental reconstruction of their spatial relationships. The advantage of multiplanar imaging in three-dimensional and four-dimensional ultrasonography is that it allows for the simultaneous visualization of three orthogonal anatomic planes, which can be very important in diagnosing cardiac abnormalities. We report, first, a case of truncus arteriosus diagnosed in utero where the multiplanar display modality provided important insight into the differential diagnosis of this conotruncal anomaly, and then, review the diagnosis of truncus arteriosus on ultrasound.     

The role of Doppler blood flow velocimetry in multiple pregnancy

This article focuses on Doppler velocimetry in the assessment of fetal growth, placental insufficiency, management of intrauterine growth restriction, discordant growth and twin-twin transfusion syndrome. Problems specific to multiple pregnancy such as twin reversed arterial perfusion, cord entanglement and visualization of anastomoses are also reviewed. Doppler sonography seems to be superior to other tests for early detection of placental insufficiency during surveillance of multiple pregnancies. It is suggested that Doppler sonography helps to select multiple fetuses who are at higher than normal risk, and might reduce perinatal mortality and morbidity. Fetal echocardiography may provide an accurate assessment of cardiovascular adaptation to intertwin transfusion, early recognition of deterioration and evaluation of antenatal management. In the management of the twin-twin transfusion syndrome, Doppler echocardiography and Doppler ultrasound examination of the venous circulation appear to be useful tools for improved perinatal management. Doppler sonography is an important adjunct in monitoring high-risk multiple pregnancies.     

Assessment of fetal behavior and general movements by four-dimensional sonography

The aim of this paper was to review the clinical applications of four-dimensional ultrasonography in the assessment of fetal behavior. With the use of a computerized database, articles on three-dimensional ultrasonography were reviewed. Several applications of dynamic three-dimensional ultrasonography have been reported, including imaging of fetal movements, facial expression and fetal hand movements. The importance of the assessment of fetal behavior by four-dimensional sonography is stressed. Four-dimensional sonography seems to be a useful imaging tool for clinical problem solving in perinatology, especially in observing the development of the central nervous system in utero.     

The study of fetal neurobehavior in twins in all three trimesters of pregnancy

Abstract

Aim: The aim was to assess the onset and the frequencies of the first intertwin contacts by four-dimensional ultrasound (4D US) in the 1st trimester of pregnancy. In the second part of the study, fetal behavior and Kurjak Antenatal Neurodevelopmental Test (KANET) score of twins compared to singletons in the 2nd and the 3rd trimesters was assessed.

Patients and methods: Transvaginal 4D assessment was performed in 20 women in the 1st trimester between 56 and 69 postmenstrual days (PMD), while trans-abdominal approach was performed from 70 PMD onwards and at weekly intervals until 112 PMD. Fetal behavior was assessed by 4D UD US between 28 and 36 gestational weeks in 49 twin pregnancies.

Results: The first intertwin contacts appeared at 61 PMD, while complex body movements appeared at 68 PMD. The complexity of intertwin contacts increased from 84 PMD. With increasing gestational age, a higher frequency of movements was observed. The number of abnormal, borderline, and normal KANET scores between singletons and twins was not statistically significant. Scores for isolated eye blinking, mouthing, grimacing, hand to head movement, finger movements, Gestalt perception and general movements differed significantly in twins and singletons.

Conclusions: Two types of activities were observed: spontaneous and reactive. Although twins showed less activity and different behavioral pattern than singletons, a considerable proportion of overall motility was due to intertwin contacts.     

Magnetic resonance imaging in human pregnancy

Magnetic resonance imaging is a new noninvasive diagnostic technique that involves no ionizing radiation, has no known significant adverse biologic effects, and produces high resolution cross-sectional body images. When compared with sonography and x-ray computed axial tomography, magnetic resonance imaging may have several advantages. To investigate its clinical role in obstetrics, magnetic resonance imaging was used to examine 11 women with abnormal pregnancies. Prior ultrasound examination showed abnormal appearing fetuses in five, abnormalities of the amnionic fluid volume in five, and one each with a large adnexal mass and a molar pregnancy. Examples of images obtained from these women are presented and described. Maternal anatomy was well visualized in all women studied. Based on the preliminary experience, the authors believe that magnetic resonance imaging will be a useful adjunct for diagnostic visualization of normal and abnormal maternal anatomy. Detailed fetal imaging was also possible, and it is anticipated that magnetic resonance imaging will prove useful for fetal evaluation, especially fetal intracranial anatomy and fetal anatomy in pregnancies complicated by oligohydramnios. Because fetal subcutaneous fat is prominently depicted with magnetic resonance imaging, this technology may be useful for assessment of fetal nutritional status.     

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

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.     

Office hysteroscopy and adenomyosis

Adenomyosis, the heterotopic presence of endometrial glands and stroma within the myometrium, has traditionally been diagnosed by the pathologist in hysterectomy specimens. However, the recent development of high-quality non-invasive techniques such as transvaginal sonography (TVS), magnetic resonance imaging (MRI) and hysteroscopy has renewed interest in diagnosing adenomyosis in the office prior to any treatment. Hysteroscopy offers the advantage of direct visualization of the uterine cavity, and since nowadays it is performed in the office, it can be offered as a first-line diagnostic tool for evaluation of uterine abnormalities in patients with abnormal uterine bleeding and/or infertility. The available data clearly indicate that high-quality mini-hysteroscopes, saline as a distension medium, and atraumatic insertion technique are essential for the success of office hysteroscopy. The procedure is indicated in any situation in which an intrauterine anomaly is suspected; it is immediately preceded by a physical exam and a TVS to evaluate uterine characteristics, and it is followed by a second TVS to take advantage of the intracavitary fluid for a contrast image of the uterus. Although diagnostic hysteroscopy does not provide pathognomonic signs for adenomyosis, some evidence suggests that irregular endometrium with endometrial defects, altered vascularization, and cystic haemorrhagic lesion are possibly associated with the entity. In addition to the direct visualization of the uterine cavity, the hysteroscopic approach offers the possibility of obtaining endometrial/myometrial biopsies under visual control. Since they can be performed in the office, the combination of TVS, fluid hysteroscopy and contrast sonography is therefore a powerful screening tool for detecting endometrial and myometrial abnormalities in association with adenomyosis.     

Prenatal diagnosis of cord entanglement in monoamniotic multiple pregnancies

Monoamniotic (MA) twins occur in about 2-5% of monochorionic (MC) pregnancies. The condition is characterized by late splitting of the developing embryo at around 8-9 days after fertilization and may also occur in higher-order multiples. During the first trimester, ultrasound diagnosis in MC-MA twins is based on visualization of only a single aniotic cavity without an intertwin membrane, and can be confirmed by the presence of only one yolk sac. The visualization of cord entanglement confirms the diagnosis at any stage of pregnancy, and has important implications for further management. Criteria for the proper diagnosis of MC-MA multiple gestation and cord entanglement are given.     

Sonographic prediction of significant intertwin birth weight discordance

OBJECT: To evaluate the usefulness of sonographic prediction of significant birth weight discordance in twin pregnancies. STUDY DESIGN: Included in the study were live twin pairs with a gestational age of 24 weeks at birth who had received a sonographic examination within 28 days of delivery. Correlation tests and ROC curves were used to evaluate the predictability of significant intertwin growth discordance. RESULTS: A total of 575 twin pregnancies were included in the study. The estimated discordance by sonographic examination proved to be an effective predictor of discordant twin growth. The birth weight discordance estimated by sonography tended to underestimate the degree of discordant twins. CONCLUSION: If a sonographic examination is done within 28 days of delivery, it is a reliable predictor of twin birth weight discordance at the following levels: 15%, 20%, 25% or 30%. In order to obtain a higher sensitivity, the cut-off value of estimated birth weight discordance needs to be decreased by 5%.     

The assessment of fetal behavior in early pregnancy: comparison between 2D and 4D sonographic scanning

AIM: To determine the accuracy of 4D sonography in the assessment of embryonic and early fetal motor activity in the first trimester of normal pregnancy, in comparison to the 2D sonography. METHODS: Fifty pregnant women between 6-14 weeks of gestation with singleton pregnancy were assigned for the investigation. Two dimensional and four dimensional recordings were displayed on the screen and recorded on the videotape during the 15 minutes observation period. RESULTS: General body, head and limb movements recorded by 2D sonography were notable by 4D technique in the same gestational age. These movements were presented collectively with maximum, minimum, and median frequencies during 15 minutes observation period. Spearman rank order correlation reached statistical significance (P<0.05) between the frequencies of all observed movement patterns assessed by two different techniques. Several movement patterns, such as sideway bending, hiccup, breathing movements, mouth opening and facial movements could be observed only by 2D sonographic technique in this period of gestation. CONCLUSION: Presently, both 2D and 4D methods are required for the assessment of early fetal motor development and motor behavior. It is reasonable to expect that such technological improvement may provide some new information about the intrauterine motor activity and facilitate the prenatal detection of some neurological disorders.     

Three-dimensional sonographic visualization of fetal skeleton in the second trimester of pregnancy

PURPOSE: To demonstrate the potential of using three-dimensional (3D) sonography to reveal anomalies of fetal skeleton. MATERIALS AND METHODS: Forty-two normal fetuses and 3 anencephalic fetuses from 14 to 27 weeks' gestation were studied with a specially developed abdominal 3D transducer (3.5 MHz). This imaging system provided conventional two-dimensional (2D) sonographic images and also generated within seconds high-quality 3D images in the surface and transparent mode with no need for an external workstation. RESULTS: Using this imaging system, we obtained 2D and 3D images of fetal skeleton (skull, scapula, spine, rib, humerus, ulna/radius, pelvis, femur, and tibia/fibula) at two gestational ages. The percentages of fetal skeletal visualization at less than 20 weeks of gestation using 3D sonography were 78-100%, whereas those with 2D sonography were all 100%. The percentages of skeletal structures revealed after 20 weeks' gestation using 3D sonography were 82-100%, whereas those with 2D sonography were all 100%. We found no significant differences in detection rates of the fetal skeleton between 2D and 3D sonography. However, 3D sonographic images generally provided a more comprehensive view of the fetal skeleton than did conventional 2D sonography. In 2 cases with anencephaly, 3D sonography clearly revealed the defect of cranium. CONCLUSION: The new 3D sonographic technology can generate within seconds high-quality 3D images of the fetal skeleton. The 3D technology seems to perform at least as well as conventional 2D sonography. Our results suggest that 3D sonography has the potential to supplement 2D sonography and might be useful in identifying malformations of the fetal skeleton and chromosomal abnormalities in utero.     

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.     

Diagnosis of endometriosis: pelvic endoscopy and imaging techniques

Although laparoscopy is the gold standard for the diagnosis of endometriosis, the need for this invasive diagnostic tool is a major stumbling-block in both effective clinical management and for research into this common and debilitating disease. As visual inspection of the pelvis has also major limitations, particularly for the diagnosis of posterior pelvis, bowel and bladder endometriosis, it is not surprising that considerable efforts are being made to improve the diagnosis by imaging techniques. Peritoneal endometriosis and ovarian endometriomata are predominantly haemorrhagic lesions. During laparoscopy, these lesions are readily identified by the presence of old or recent bleeding. Both transvaginal sonography and magnetic resonance (MR) imaging have a low sensitivity for the diagnosis of peritoneal and ovarian implants and adhesions. Transvaginal sonography is useful in the diagnosis of ovarian endometriomata, providing the diameter is larger than 2 cm. As transvaginal sonography costs less than MR imaging, transvaginal sonography might be the preferred method of confirming a sizeable endometrioma. Posterior pelvis endometriosis is an infiltrating adenomyotic lesion with microendometriomata. High-resolution transvaginal ultrasonography, and in particular MR imaging, are increasingly used to diagnose the presence and extent of infiltrating lesions and the involvement of rectosigmoid and ureters.     

The use of echo-enhancing contrasts in gynecology

Echo-enhancing contrasts enable more complete visualization of ovarian and uterine blood vessels in both normal and abnormal conditions. In this review, we report on the advantages of echo-enhanced B-mode imaging, harmonic B-mode imaging, harmonic power Doppler imaging, pulse-inversion imaging, release-burst imaging and subharmonic imaging. Enhanced three-dimensional (3D) power Doppler imaging was used to determine whether the imaging patterns of identified vessels could be correlated with histopathological results, and to evaluate whether the information obtained with echo-enhanced 3D power Doppler ultrasound could improve the diagnostic accuracy in adnexal lesions, compared to that with non-enhanced 3D power Doppler ultrasound. The presence of penetrating vessels was used as a diagnostic criterion for ovarian malignancy. Non-enhanced 3D power Doppler ultrasound in this study demonstrated a diagnostic sensitivity of 58.33% and a specificity of 96.97%. With regard to differential diagnosis between malignant and benign ovarian lesions, contrast-enhanced 3D power Doppler sonography reached a diagnostic sensitivity and specificity of 100% and 93.94%, respectively. The practical value of this modality requires further comparative studies of the diagnostic performance of 3D power Doppler ultrasound with and without injection of contrast agents, as well as evaluation of the cost effectiveness.     

Determining chorionicity and amnionicity in twin pregnancies: Pitfalls

Although the accuracy of chorioamnionicity determination in multiple pregnancy is nearly 100%, some pitfalls do exist. These pitfalls may arise from some confusing sonographic appearance or because of certain rare variations of twinning going against the general principles. Pitfalls in chorionicity determination include (1) the disappearance of the twin peak sign with the regression of chorion frondosum and thinning of the intertwin membrane with advancing gestation; (2) fake twin peak sign because of other structures creeping into the intertwin membrane-placental junction; (3) intrauterine septum or synechia being mistaken as a thick intertwin membrane; (4) bipartite placenta in monochorionic twin being misinterpreted as two separate placentas of dichorionic twin; (5) erroneous fetal sex determination in sex chromosome mosaicism, monogenic disorders, and malformed genitalia in one fetus; and (6) rare twinning types such as dizygotic monochorionic twin and sesquizygotic twin. Pitfalls in amnionicity determination are (1) the lack of correlation between the number of yolk sacs and amnionicity and (2) failure to visualize the intertwin membrane because of technical issues.     

Three-dimensional sonographic features of nuchal edema

OBJECTIVE: To describe the three-dimensional (3D) sonographic features of nuchal edema in the early second trimester of pregnancy. METHODS: From 16 to 22 weeks of gestation 5 cases with nuchal edema were studied using transabdominal 3D sonography. RESULTS: Nuchal edema could be easily imaged with both two-dimensional and 3D sonography; however, visualization of the continuity and curvature of structures was more easily accomplished with 3D sonography. Before 20 weeks of gestation, the skin has a transparent structure, so the bony structures are clearly identified. 3D sonography allowed visualization of nuchal edema in all three dimensions at the same time, providing an improved overview and a more clearly defined demonstration of the adjusted anatomical planes. CONCLUSION: These results suggest that 3D sonography provides a novel means of visualizing nuchal edema in utero.     

Intertwin time interval: how it affects the immediate neonatal outcome of the second twin

OBJECTIVE: Customarily 30 minutes is used as the upper limit of intertwin birth times. This study was conducted to define factors that influence the immediate neonatal outcome of the second twin and to assess whether a valid cutoff time is evident. STUDY DESIGN: We evaluated all live born viable vaginal twin deliveries (144) between November 1997 and December 2003. The relationship between intertwin birth time and neonatal outcome was then evaluated continuously and in 15 to 30-minute intervals. RESULTS: In multivariate analysis, only intertwin birth time predicted umbilical cord pH. Arterial/venous pH decreased linearly at a rate of 0.00063 and 0.00081 U/min. Venous pH was significantly lower in later 15-minute intervals compared with earlier ones (P = .002), and in patients delivering before or after a 30-minute cutoff (7.31 vs 7.26, P = .012). CONCLUSION: Our study confirmed that longer intertwin birth time is associated with a continuous slow decline in umbilical cord pH. However, the small differences in pH were not large enough to impact clinical management.     

Recent advances in the sonographic assessment of vascularity and blood flow in gynecologic conditions

OBJECTIVE: This overview presents recent advances in sonographic depiction of vascularity and blood flow in the uterus, ovaries, and breasts. Enhanced sonographic visualization and evaluation of intraorgan vascularity has resulted from improved image processing and display. Future advances, such as the use of contrast enhancement, are also mentioned in this overview as one of many topics for future investigation. STUDY DESIGN: This is an overview of the topic based on review of the literature and the authors' experience. RESULTS: Specifically, the sensitivity of color Doppler sonography has been enhanced with the use of amplitude or power Doppler techniques. Spatial depiction of vascularity has improved because of 3-dimensional and "live 3-dimensional" processing. CONCLUSION: The combination of more sensitive color Doppler sonography and 3-dimensional imaging provides both anatomic and physiologic assessment of the vascularity and blood flow of the ovary, uterus, and breast.     

Fetal serum levels of insulin,growth hormone and insulin-like growth factor-I in concordant and discordant twin gestations

Objective: To examine the role of insulin, growth hormone and insulin-like growth factor (IGF)-I in concordant and discordant twin pairs. Methods: Umbilical cord serum samples were obtained from 20 twin pairs with weight discordancy (intertwin birth weight difference > 20%) and from 20 concordant twins (intertwin birth weight difference < 20%), both groups of similar gestational age, gravidity, and parity. The serum samples were analyzed for the levels of IGF-I, growth hormone and insulin in both maternal and fetal compartments. Results: Among the group of discordant twins, the normally grown twin, in all cases, had significantly higher cord serum IGF-I levels than their growth-restricted co-twin (108 &#45 73 ng/ml vs. 39 &#45 24 ng/ml; p < 0.01). There were no significant intertwin differences in the cord blood IGF-I levels in the concordant twin pairs (87 &#45 44 vs. 88 &#45 48 ng/ml; p = 0.986). Insulin and growth hormone levels did not correlate with intertwin birth weight differences. Conclusion: These data demonstrate that IGF-I is important in the regulation of both normal and restricted fetal growth in utero, and its action appears to be, at least in part, through an endocrine action. The precise role of growth hormone and insulin in fetal growth restriction remains uncertain.