Fetal Neurosonogaphy: Ultrasound and Magnetic Resonance Imaging in Competition

Both in routine diagnostics and detailed, highly specialized workups, major advances have been observed in many areas of ultrasound due to an increase in expertise and improved technology in recent years. This is particularly true in the case of fetal neurosonography 1 2 3 4. Malformations of the CNS together with fetal heart defects are among the most common congenital anomalies. From the embryonic phase to the late third trimester, the CNS undergoes extensive development and maturation processes. The diagnosis of CNS anomalies is therefore primarily dependent on the time at which the examination is performed and the experience of the examiner. The introduction of transvaginal and 3 D ultrasound for evaluating fetal brain structures has made it possible to diagnose pathological findings of the CNS with increasing accuracy 5. The detection rates for CNS anomalies are up to 90 - 95 % depending on the finding 3 5. Today, detailed fetal neurosonography also includes differential diagnostic evaluation of the posterior cranial fossa, the corpus callosum (CC), and the gyri and therefore exceeds the primarily conspicuous, non-specific diagnosis of "ventricular dilation" often occurring as an accompanying symptom 6 7 The article "Prenatal Diagnosis of Corpus Callosum Anomalies" appearing in this issue shows an increase in the frequency of diagnosis and also shows that it is possible to differentiate between complete and partial corpus callosum agenesis and hypoplasia of the corpus callosum with differentiation between isolated and non-isolated cases is possible on ultrasound. In 4 of 44 cases in which both neurosonography and intrauterine MRI were performed, there was a discrepancy between the ultrasound diagnosis and the intrauterine MRI findings. In a comparison of the sonographic diagnoses and the MRI findings, additional pathologies were seen on MRI but not on ultrasound in only 3 of 44 cases. In a further case of CC hypoplasia, the sonographic diagnosis was superior to the MRI findings.Another study appearing in this issue study of CNS anomalies in fetuses with complex clubfoot also showed additionally diagnosed CNS anomalies in 4 cases on MRI. MRI yielded supplementary findings that were not visible on ultrasound in 6 cases. Although the number of cases is small, it was able to be shown, as in other studies, that a certain percentage of CNS anomalies is able to be evaluated on an additional or supplementary basis on MRI.Since intrauterine MRI has been becoming increasingly important in recent years, it is necessary to determine when MRI is indicated. There is general consensus in the literature that MRI is not a screening method for detecting fetal anomalies but should be viewed as a supplementary method to ultrasound 8 9 10. However, MRI application in pregnancy is increasing. Intrauterine MRI is most commonly used in the case of abnormal ultrasound findings regarding the CNS 11 12 13. This includes morphological evaluation of malformations and recently also of acquired hypoxic-ischemic diseases, bleeding and inflammation such as CMV infections. Thoracic and abdominal malformations are also indications for MRI for the evaluation of the lung volume in diaphragmatic defects and in the case of suspicion of esophageal atresia abnormal placentation. Further possible indications for the use of MRI include monochorial multiple pregnancies with a feto-fetal transfusion syndrome (for the evaluation of neurological development) and select cases with known diseases and syndromes 14. The majority of studies for comparing intrauterine MRI to sonographic diagnosis include a small number of cases with limited or no follow-up. Data regarding sensitivities, specificities, and positive predictive values is limited. Many studies simply calculate the difference in percentages on the basis of a small number of cases. The best available data is in regard to CNS anomalies. In one of the few meta-analyses including 34 studies and documented follow-up in 959 fetuses, intrauterine MRI was correct in 91 % of cases which was an increase of 16 % above that achieved by ultrasound 15. This means a significant diagnostic gain for specific issues. However, it must be taken into consideration that the analysis includes a period of 20 years and fetal neurosonography has made major progress in this time. The diagnostic gain would tend to be smaller today. In many studies the level of experience of the ultrasound examiners often remains unclear A possible bias is also that an examiner with less experience determines an indication for intrauterine MRI faster and more frequently and can thus gain more information compared to highly specialized, experienced ultrasound examiners in prenatal centers. Since advanced training in prenatal diagnosis is becoming increasingly difficult due to the transfer of centers to ambulatory practices, there is a certain risk that crash courses or brief internships in ultrasound will result in intrauterine MRI playing an additional role in fetal differential diagnosis and in the confirmation of findings. Because intrauterine MRI is stressful for pregnant women, indiscriminate indication for MRI cannot be recommended even if no fetal damage is to be expected provided that the appropriate safety measures are observed (examination duration of approx. 30 minutes and implementation of MRI after 18 weeks of gestation). After a properly performed ultrasound examination, little additional morphological information can be gained from MRI 16. However, in the case of an unclear sonographic finding or in the event of therapeutic consequences for the care of the fetus or for the birth, MRI is an excellent supplementary method to ultrasound. Concretely, this means ultrasound first. If the finding is not clear, intrauterine MRI can be used as an adjunct method. In this way the cost-benefit ratio can be optimized. The gains achieved by MRI compared to US depend on the quality of the examination and thus on the expertise of the examiner in both methods. The indications for fetal MRI should also follow defined standards based on a protocol adapted to the particular clinical issue 16.

Quality Requirements for the early Fetal Ultrasound Assessment at 11-13+6 Weeks of Gestation (DEGUM Levels II and III)

The early fetal ultrasound assessment at 11 - 13(+6) weeks of gestation remains the cornerstone of care despite the progress in diagnosing fetal chromosomal defects using cell-free fetal DNA (cffDNA) from the maternal circulation. The measurement of nuchal translucency (NT) allows the risk calculation for the fetal trisomies 21, 18 and 13 but also gives information on those fetal chromosomal defects which are at present unable to be detected using cffDNA. Nuchal translucency is the only auditable parameter at 11 - 13(+6) weeks and gives thus information on the quality of the first trimester anomaly scan. In addition it gives indirect information on the risks for fetal defects and for cardiac anomalies. Also the chances for a healthy live baby can be estimated. As experience with first trimester anomaly scanning increases, and the resolution of the ultrasound equipment has increased substantially, more and more details of the fetal anatomy become accessible at the first trimester scan. Therefore fetal anatomical defects and complex anomalies have become amenable to examination in the first trimester. This guideline describes compulsory and optional parameters for investigation at the first trimester scan and outlines a structured method of examining a first trimester fetus at 11 - 13(+6) weeks of gestation.

Exome sequencing identifies mutations in KIF14 as a novel cause of an autosomal recessive lethal fetal ciliopathy phenotype

Gene discovery using massively parallel sequencing has focused on phenotypes diagnosed postnatally such as well-characterized syndromes or intellectual disability, but is rarely reported for fetal disorders. We used family-based whole-exome sequencing in order to identify causal variants for a recurrent pattern of an undescribed lethal fetal congenital anomaly syndrome. The clinical signs included intrauterine growth restriction (IUGR), severe microcephaly, renal cystic dysplasia/agenesis and complex brain and genitourinary malformations. The phenotype was compatible with a ciliopathy, but not diagnostic of any known condition. We hypothesized biallelic disruption of a gene leading to a defect related to the primary cilium. We identified novel autosomal recessive truncating mutations in KIF14 that segregated with the phenotype. Mice with autosomal recessive mutations in the same gene have recently been shown to have a strikingly similar phenotype. Genotype-phenotype correlations indicate that the function of KIF14 in cell division and cytokinesis can be linked to a role in primary cilia, supported by previous cellular and model organism studies of proteins that interact with KIF14. We describe the first human phenotype, a novel lethal ciliary disorder, associated with biallelic inactivating mutations in KIF14. KIF14 may also be considered a candidate gene for allelic viable ciliary and/or microcephaly phenotypes.

[Current aspects of obstetric ultrasound in the screening setting]

Screening ultrasound during pregnancy has an established role and a defined scope that has increased over the years. Diagnostic possibilities with newer ultrasound systems can help in particular in referral settings and for a more detailed analysis of various fetal organ systems. In particular for the fetal heart there is a clear benefit with regard to neonatal morbidity and mortality.

Prenatal counseling--implications of the cultural background of pregnant women on information processing, emotional response and acceptance

PURPOSE

Providing information about prenatal diagnosis (PND) that leads to an informed decision is ethically and psychologically challenging, especially in an intercultural context. The aim was to investigate cultural differences in information processing, test interpretation, evaluation of an established information leaflet, emotional response during screening and acceptance of PND.

MATERIALS AND METHODS

This prospective study compared 30 pregnant Turkish immigrants with 30 women from Switzerland and countries within the European Union (EU). They completed a questionnaire prior to (T1) and after risk assessment between 11-14 weeks (T2) and after receiving the results (T3). The questionnaire focused on the perception of, experiences with and knowledge about the risk assessment and included the hospital anxiety and depression scale (HADS). χ(2) tests were used for dichotomous variables and Student's t-tests for scores on perception, experience, knowledge, depression and anxiety. Groups were compared over time by 2-factorial ANOVA.

RESULTS

Regarding the 6 questions on knowledge, the rate of correct answers was between 32.2% and 62.5% at T1 and 35.1% and 75.0% at T2. The Turkish women's knowledge level was significantly lower. They rated the information leaflet as less helpful and found the counseling significantly more unsettling. The acceptance of PND was higher in Turkish women.

CONCLUSION

Considering the information and knowledge deficits, informed consent was not given in every case, especially in Turkish women. Nevertheless, the acceptance of PND was good. Further studies will have to focus on counseling strategies that take into account the specific needs and expectations of pregnant women with different cultural backgrounds.

Is a routine ultrasound in the third trimester justified? Additional fetal anomalies diagnosed after two previous unremarkable ultrasound examinations

PURPOSE

The detection of fetal structural abnormalities is a routine part of antenatal care. Ultrasound examination policies vary among European countries. An additional ultrasound for fetal structural anomalies in the 3 rd trimester seems important for many reasons. Some abnormalities develop or first become apparent later in pregnancy. The aim of the study was to analyze the rate of previously undetected structural abnormalities in the 3 rd trimester.

MATERIALS AND METHODS

8074 fetuses were examined in this prospective study between 1998 and 2008. All received an examination at 11 - 14 weeks and 79 % (6378 / 8074) of these fetuses also received an ultrasound at 20 - 24 weeks. If both of the examinations did not detect structural abnormalities, the fetuses were included in the study group and received an ultrasound at 28 - 32 weeks (n = 5044). New structural abnormalities in the 3 rd trimester were analyzed. The outcome was available in 96 % of the cases.

RESULTS

The overall incidence of fetal malformations was 3.6 % (n = 289), of which 40 % (116 / 289) were diagnosed at 11 - 14 weeks. The following 2nd trimester scan revealed 102 (35 %) new fetal malformations. An additional 44 (15 %) structural abnormalities were found in the 3 rd trimester. These were mainly abnormalities of the urogenital system (n = 18). There were also anomalies of the cardiovascular system (n = 9), the gastrointestinal system (n = 6) and the central nervous system (n = 4). One of the cases had a previously undiagnosed abnormal karyotype.

CONCLUSION

The ultrasound examination in the 3 rd trimester is of additional benefit and can detect previously unknown structural abnormalities. These findings are relevant for perinatal management and postnatal follow-up.

[Pregnant women's assessment and level of knowledge of prenatal counseling]

PURPOSE

Informed decision making and informed consent prior to any intervention are crucial in the ethically and psychologically complex field of prenatal diagnosis (PND). The aim of this study was to investigate whether and to what extent pregnant women understand the information provided by their physicians.

MATERIALS AND METHODS

Fifty pregnant women in the first trimester answered a structured questionnaire after their first visit between 7 to 10 weeks of gestation that routinely includes basic prenatal counseling. A special focus was put on information transfer, knowledge about and understanding of prenatal tests, as well as previous experiences with PND. The results were analyzed with regard to differences due to background, educational level and previous experiences with PND.

RESULTS

The maternal mean age was 31.1 years (SD 6.7). 38 patients (76 %) had at least one previous pregnancy and two thirds of them had experiences with PND. Their experience was mainly positive. About three quarters of the women stated that they had been informed about the test methods during the consultation and had understood the explanations. Uncertainty was reported in 12.2 % and 23.3 % of the women said they had further questions. The percentage of questions related to appropriate understanding that were answered correctly was only 44 % to 77.5 %. The percentage of correct answers was lower in women without experience with PND, with a lower educational level and born in countries outside the EU and Switzerland.

CONCLUSION

Pregnant women are relatively well informed about prenatal tests. Their actual knowledge of the meaning of the tests, however, seems to be incomplete. Especially in the case of immigrants and women without previous experience with PND, it is therefore doubtful whether the preconditions for an informed consent are met. Further research needs to focus on more helpful information and individually adapted counseling concepts for decision making in PND.

[Prenatal diagnosis of diastematomyelia and tethered cord - a case report and review of the literature]

Diastematomyelia is a rare form of occult spinal dysraphism. It is characterized by longitudinal clefting and separating of the spinal cord by a bony or fibrous spur. Diastematomyelia is associated with other anomalies, i. e. spina bifida, scoliosis, visceral malformations or anomalies of the overlying skin. Prenatal diagnosis is based on fetal ultrasound supplemented by fetal MRI. We present a case of diastematomyelia and prenatal diagnosis in the 23rd gestational week using routine ultrasound scanning and confirmation by fetal MRI. After vaginal delivery at term, the child's development is normal. Prenatal diagnosis of isolated diastematomyelia is challenging. Management and prognosis are still controversial as only few cases have been reported. Affected fetuses might benefit from early diagnosis enabling surgical intervention before the development of neurological sequelae.

Quality management of nuchal translucency measurement in residents

PURPOSE

The measurement of the nuchal translucency (NT) in the 1st trimester is a sensitive, reliable method to assess the risk of specific fetal chromosomal and other defects. Training, however, is an issue not only among experienced sonographers, but especially for ObGyn residents, since all NT measurements in a true screening setting should fulfil the quality standards. The aim of this study was therefore the evaluation of the learning curve of residents and determination of the number of measurements necessary to achieve acceptable results.

MATERIALS AND METHODS

Between 30th June, 1997 and 8th August, 2003, we included 4450 subsequent pregnant women between 11+0 and 13+6 weeks of gestation referred for an NT scan and prenatal counselling (low and high risk patients) in the study. For analysis of the learning curve in residents, all NT scans performed either by the experienced sonographers only or by residents with less than 70 scans at the end of their training were excluded. As the main quality criterion, the percentage of cases above the median was used. To test for normal distribution of NT scans, the Kolmogorov-Smirnov test was used.

RESULTS

Each of 19 residents fulfilling these criteria performed 131 NT scans (73-242) on average. 13 of 19 residents ultimately met the quality criteria, but the majority of residents achieved good quality only after 100 scans, whereas 6 of 19 never did. Only after at least 50 NT scans, 50% of measurements were above the median, whereas before these 50 scans, NT was usually underestimated.

CONCLUSION

It became obvious that regular supervision and quality control is mandatory to provide exact NT measurements by residents. Based on our results, a minimum of 100 NT scans is recommended before diagnostic application, which is a higher requirement than implemented in widely accepted quality assurance programs.

[Communication skills for prenatal counselling]

Prenatal counselling is characterized by specific characteristics: A):The communication is about the values of the pregnant woman and her relationship with the child to be. B) The communication deals with patient's images and emotions. C) It is a communication about risks, numbers and statistics. D) Physician and patient deal with important ethical issues. In this specific setting of prenatal diagnosis and care physicians should therefore learn to apply basic principles of patient-centred communication with elements of non directive counselling, patient education and shared decision making. These elements are integrated into a process which comprises the following "steps": 1. Clarification of the patient's objectives and the obstetrician's mandate. 2. The providing of individualized information and education about prenatal tests and investigations. 3. Shared decision making regarding tests and investigations 4. Eventually Breaking (bad, ambivalent) news. 5. Caring for patients with an affected child.

Neue Möglichkeiten in der pränatalen Diagnostik

Mit den technischen Entwicklungen erweiterten sich in den letzten Jahren die Einsatzmöglichkeiten des pränatalen Ultraschalls. So konnten in den 80er und 90er-Jahren zunehmend fetale Fehlbildungen diagnostiziert und spezifiziert werden. Die Untersuchung mit der sonographischen Nackentransparenzmessung in der 11. bis 14. Schwangerschaftswoche findet nunmehr als wichtiges pränatales Screening zur individuellen Risikoabschätzung für Chromosomenstörungen Eingang in die pränatale Medizin. Neben der standardisierten Untersuchungstechnik sollte größter Wert auf die ausführliche Information und Beratung der Schwangeren sowie auf die Qualitätssicherung gelegt werden. Durch die Verbesserung der individuellen Risikospezifizierung mittels Sonographie, biochemischen Markern und dem mütterlichen Alter können unnötige invasive Untersuchungen vermieden und ihre Zahl insgesamt deutlich reduziert werden. Ein Trend, der sich auch anhand des nicht-invasiven Nachweises des fetalen Rhesus D Status und mit dem Einsatz der Dopplersonographie im Management fetaler Anämien verfolgen lässt.

[Sonographic first trimester screening in Switzerland]

The sonographic measurement of the nuchal translucency is already regarded as the most valuable screening parameter for chromosomal anomalies. Beside standardised examinations profound information and counselling of the pregnant women should be emphasised. With the improvement of the specific maternal risk calculation using the sonographic measurement of the nuchal translucency, the biochemical markers and the maternal age, unnecessary invasive examinations may be prevented and their overall number can be reduced significantly.

Lost intrauterine devices during pregnancy: maternal and fetal outcome after ultrasound-guided extraction. An analysis of 82 cases

OBJECTIVES

It is generally agreed that intrauterine devices (IUDs) with visible strings in pregnancy should be removed because of the increased risk of miscarriage, septic complications and premature delivery. The precise management of pregnancies in association with so-called 'lost IUDs', and especially the technique of their removal, has remained controversial. We present our experience of the management of intrauterine pregnancies with a lost IUD.

METHODS

Ultrasound-guided extraction of a lost IUD was performed in 82 intrauterine pregnancies. The subsequent outcome of the pregnancies is described.

RESULTS

There were no intra- or post-procedure maternal complications. Although the miscarriage rate in the first 3 weeks after the procedure was higher than that in normal pregnancy, the complication rate approached that of normal pregnancy as the pregnancies progressed. The total miscarriage rate of 22% was comparable to that following extraction of IUDs with visible filaments. The rate of live births was 77.0%. Delivery before 37 weeks occurred in 13.5% of cases.

CONCLUSIONS

Ultrasound-guided extraction is a minimally invasive and inexpensive procedure that is associated with few postoperative complications. It has a high success rate and is associated with a moderate miscarriage rate and no maternal complications.

Comparison of pregnancy outcome of euploid fetuses with increased nuchal translucency (NT) expressed in NT MoM or delta-NT

OBJECTIVE

To evaluate the outcome of euploid fetuses with increased nuchal translucency thickness (NT) expressed in multiples of the median (MoM) or delta-NT.

METHODS

Included in the study were euploid fetuses with increased NT >or= 95(th) centile, for which information about pregnancy outcome was available. The following parameters were defined as an adverse outcome: miscarriage, structural anomalies justifying termination of pregnancy, and structural anomalies, genetic syndromes and neurodevelopmental problems diagnosed postnatally. Fetal outcome according to NT MoM and delta-NT was calculated using different cut-off values. Calculations of the odds ratio for adverse outcome were performed using either NT MoM or delta-NT as a predictor in logistic regression models.

RESULTS

The study comprised 168 euploid fetuses. Of these, 38 (23%) had an adverse outcome: 11 (6%) had miscarriages, 14 (8%) were terminated because of fetal abnormalities detected on the prenatal scan and 13 (7%) were found postnatally to have abnormalities. The incidence of cases exhibiting an adverse outcome was 5.3%, 19.2% and 58.5% for NT values of 1.6-1.9, 2.0-3.0 and >3.0 MoM, respectively (P < 0.0001, chi(2) test), and 3.9%, 16.7% and 62.8% for delta-NT values of 1.0-1.4, 1.5-2.5 and >2.5 mm, respectively (P < 0.0001, chi(2) test). Using cut-offs of 2.0 MoM and delta-NT of 1.5 mm, the odds ratios for adverse outcome were 10.2 (95% CI, 3.4-30.4) and 15.4 (95% CI, 4.2-43.6), respectively.

CONCLUSION

Both the NT MoM and delta-NT approaches may be used to determine cases which require additional antenatal investigation as well as fetal karyotyping. For this purpose we suggest using a cut-off of either 2.0 MoM or a delta-NT of 1.5 mm.

[Ultrasound in pregnancy--practical aspects]

According to the payments agreement of the health insurance law two screening-scans at 10-13 weeks and 20-23 weeks respectively are part of the low-risk pregnancy care. The first-trimestre-scan includes the determination of the gestational age, the anatomical integrity of the fetus and the chorionicity in case of monochorionic twins. The 20-23 week scan has to evaluate the fetal growth, fetal abnormalities and the placental site. Doppler sonography is reserved for high risk pregnancies, especially for hypertensive disorders and fetal growth retardation, for the evaluation of fetal anemia in case of blood group alloimmunisation and for the detection of the twin-twin-transfusion syndrome in monochorionic twins.

Umbilical cord edema associated with patent urachus

Umbilical cord anomalies can often be detected prenatally by ultrasound, but a definitive prenatal diagnosis is not always possible. We present a case with increasing edema of the Wharton's jelly followed by the development of pseudocysts in the proximal umbilical cord due to a patent urachus. The first abnormal findings were detected by ultrasound in the 14th week of gestation. Differential diagnoses and their influence on surveillance and birth management are discussed.

[Genetic testing in pregnancy]

First trimester risk screening is probably the major methodological advance in identifying pregnancies at increased risk for genetic disease during recent years with an impact on all pregnancies. The high detection rate with moderate false positive rates will reduce the over-all number of invasive procedures as compared to the traditional approach based on maternal age exclusively, in particular considering the demographic shift towards higher mean maternal age. Non-invasive prenatal diagnosis from fetal cells or DNA in the maternal circulation remains an experimental approach, despite a growing number of reports on successful diagnoses of single gene disorders. In the lab molecular cytogenetic approaches have considerably broadened the diagnostic spectrum of conventional karyotyping and facilitated a rapid diagnosis of selected frequent aneuploidies. Molecular genetic testing, in particular on chorionic villi, allows an early and reliable diagnosis of a growing number of severe monogenic conditions. A restrictive legislation has hampered the development of preimplantation genetic diagnosis in German speaking countries, only a few groups work on polar body diagnosis, a legal but restricted alternative.

Charts for cervical length in singleton pregnancy

OBJECTIVES

To construct charts for cervical length in a low risk population measured by transvaginal ultrasonography.

METHODS

Pregnant women of an apparently normal population were seen in the ultrasound division of the University Women's Hospital Basel between 20 and 34 weeks of gestation and underwent once (one measurement per subject) a transvaginal ultrasound measurement of the cervix under standardized conditions. In order to establish normal values of the cervical length, finally only women who delivered spontaneously at term (>37 weeks of gestation) remained in the study. Exclusion criteria were preterm labor, multiple pregnancies, cerclage or surgical intervention prior to pregnancy. For statistical evaluation, regression analysis and calculation of 5th and 95th percentiles were performed.

RESULTS

A total of 669 cervical measurements were recorded. The number of measurements differed from 22 measurements at 23 weeks of gestation to 86 at 31 weeks of gestation. Cervical length gradually and significantly decreased as the gestational age progressed (between 20 and 34 weeks of gestation). New charts with the 5th, 50th and 95th percentile are presented and compared with previously published data.

CONCLUSIONS

Our charts for cervical length in a limited risk population can be used for observing patients at high risk of preterm delivery and for clearly identifying a significant deviation or decline in the percentile for these subjects.

Bedside estimation of Down syndrome risk during first-trimester ultrasound screening

OBJECTIVE

To construct tables for 'bedside' estimation of Down syndrome risk based on maternal age and nuchal translucency measurements.

METHODS

Likelihood ratios were calculated using the log multiple of median Gaussian model. The parameters for the model (mean and standard deviation) were derived from 5560 normal and 51 Down syndrome-affected pregnancies scanned during the first trimester in three different centers. Equations for calculating maternal background risk and median values were obtained from previous reports. The results were compared to two modalities using the log Gaussian model and software that uses the delta-value model.

RESULTS

The distribution fitted the data well, and the parameters obtained in the study group for the log multiple of median model were a mean of 0 and a standard deviation of 0.12356 among normal pregnancies and a mean of 0.305312 and a standard deviation of 0.240337 among Down syndrome-affected ones. The likelihood ratios obtained for the various combinations of fetal crown-rump lengths and nuchal translucency measurements were comparable to other modalities reported earlier.

CONCLUSIONS

The results of the current study provide useful tables for simple and accurate 'bedside' estimation of Down syndrome risk without the need for computerized software or complicated calculations.

Split hand and foot malformation: ultrasound detection in the first trimester

The split hand split foot malformation is a rare disorder inherited in an autosomal dominant pattern with variable expression. In our case it was detected early by ultrasound in the twelfth week of gestation. To our knowledge, this is the earliest finding by ultrasound of this malformation. The sonographic findings were bilateral split hands and split foot. No other associated malformation was observed. The pathological findings were consistent with the diagnosis of split hand split foot malformation. Prenatal diagnosis, the genetic background, and the differential diagnosis are discussed.

Prenatal diagnosis of an infratentorial subdural hemorrhage: case report

We report a case of a prenatally diagnosed infratentorial subdural hemorrhage. The hematoma located in the posterior cerebral fossa was detected by conventional ultrasound at 24 weeks of gestation. Intrauterine magnetic resonance imaging confirmed the diagnosis. Autopsy of the fetus revealed a well-circumscribed subdural hematoma. The prenatal findings of intracranial bleeding located in the posterior fossa and the prognosis of such cases are discussed.

[Pregnancy outcome in 1,252 fetuses after nuchal translucency measurement in the 1st trimester]

The measurement of the nuchal translucency is an important marker to detect a vast number of fetal anomalies. Lately the nuchal translucency has been used increasingly as a screening method to find chromosomal anomalies especially for trisomy 21. Beside a high incidence of chromosomal defects one assumes a high risk of rare syndromes and other associated anomalies such as heart defects, skeletal anomalies, cerebral anomalies, diaphragmatic hernias, as well as of an intrauterine death. In view of abortion rate, detection rate of chromosomal anomalies, other fetal anomalies and rare syndromes we evaluated in this study the pregnancy outcome after nuchal translucency measurement, and discuss a concept for its management.

Differentiation and management of endometrium abnormalities and leiomyomas by hydrosonography

Transvaginal sonography is an established method for numerous clinical indications in the assessment of endometrium pathology. The investigation of the endometrium consists of the measurement of the thickness, the visualization of the echogenity and echotexture and of the demonstration of focal masses. However, evaluation of the uterine cavity by transvaginal sonography is limited and an abnormal ultrasound of the endometrium may reflect benign or malignant conditions. Furthermore, small structures can be missed or overlooked. If indicated, hydrosonography offers various advantages compared to dilatation and curettage and hysteroscopy in terms of costs, availability and risks. Additional informations obtained after hydrosonography may influence the management before consideration of curettage or hysteroscopy.

[Screening for aneuploidy by first trimester nuchal translucency measurement: results from a prospective trial including 1980 cases in a single center in Switzerland]

AIM

The purpose of this study was to evaluate the efficiency of first trimester screening for chromosomal abnormalities using the sonographically determined thickness of nuchal translucency (NT) combined with maternal age.

PATIENTS AND METHODS

Risk screening was offered to all patients with a fetal crown rump length (CRL) between 45 and 84 mm after extensive counselling. For the risk assessment the software provided by the Fetal Medicine Foundation was used. In accordance with the recommendation of the Swiss Working Group on First Trimester Screening a cut-off risk of 1 : 400 was chosen.

RESULTS

A total of 1980 consecutive pregnancies participating in the risk screening programme with due dates prior to May 1, 2001 were included. Mean maternal age was 30.1 yrs and 522 (26.4 %) patients were 35 yrs or older. A positive risk screening result was obtained in a total of 219 (11.1 %) pregnancies including 33 of the 37 (1.9 %) cases with unbalanced chromosomal abnormalities.

CONCLUSIONS

The detection rate for unbalanced chromosome abnormalities in general (89.2 %) as well as the one for trisomy 21 (93.3 %) in particular are very high with a moderate false-positive rate (9.6 %) in this series. As a comparison in the series presented here, traditional "maternal age screening" (cut-off age 35 yrs) would have yielded detection rates of 64.9 % for all unbalanced chromosome abnormalities and 73.3 % for trisomy 21 at a false-positive rate of 25.0 %. Reducing the false-positive rate by raising the cut-off age to 38 yrs would yield detection rates of 40.5 % for all unbalanced chromosome abnormalities and 46.7 % for trisomy 21 at a false-positive rate of 8.9 %. The number of invasive procedures performed to detect one unbalanced chromosome count may be calculated as 21.75 using the cut-off age of 35 yrs as compared to 6.4 using NT measurement and maternal age. The outcome of this ongoing study is in good accordance with the earlier observation that the main benefit of the addition of first trimester NT measurements to the risk screening protocol is a very high detection rate at a moderate false-positive rate.

Screening for trisomy 21 by fetal nuchal translucency and maternal age: a multicenter project in Germany, Austria and Switzerland

OBJECTIVE

To examine the effectiveness of screening for trisomy 21 by a combination of maternal age and fetal nuchal translucency thickness at 10-14 weeks of gestation in Germany, Austria and Switzerland.

METHODS

This was a multicenter study of screening for trisomy 21 by a combination of maternal age and fetal nuchal translucency thickness at 10-14 weeks of gestation. All the sonographers involved in the study had received The Fetal Medicine Foundation Certificate of Competence in the 10-14-week scan. Fetal nuchal translucency thickness and crown-rump length were measured in 23 805 singleton pregnancies with live fetuses. In each case the risk for trisomy 21 was estimated on the basis of maternal age and fetal nuchal translucency thickness for crown-rump length with the use of The Fetal Medicine Foundation's software. The distribution of estimated risk was determined and the sensitivity and false-positive rate for a risk cut-off of 1 in 300 was calculated.

RESULTS

Fetal nuchal translucency thickness was successfully measured in all 23 805 pregnancies and outcome was available in 21 959. The median maternal age was 33 (range 15-49) years and in 7935 (36.1%) the age was 35 years or greater. The median gestation at screening was 12 (10-14) weeks and the median fetal crown-rump length was 61 (range 38-84) mm. The estimated risk for trisomy 21 based on maternal age and fetal nuchal translucency thickness for crown-rump length was 1 in 300 or greater in 13.0% (2800 of 21 475) normal pregnancies, in 87.6% (184 of 210) of those with trisomy 21 and in 87.2% (239 of 274) with other chromosomal defects.

CONCLUSIONS

In Germany, Austria and Switzerland the results of screening for chromosomal defects by measurement of fetal nuchal translucency thickness, in centers with appropriately qualified sonographers and using The Fetal Medicine Foundation's software, are similar to those reported in the UK using the same methodology.

Large placental chorioangioma as a cause of sudden intrauterine fetal death. A case report

A giant placental chorioangioma was diagnosed in a fetus at 22 weeks of gestation by prenatal ultrasound screening and color Doppler imaging. Although no signs of fetal hydrops and cardiac decompensation were observed, the situation of the fetus deteriorated rapidly and in utero fetal death occurred at 26 weeks, attributed to bleeding from ruptured sinusoids within the tumor. Prenatal diagnosis of chorioangioma and treatment modalities are discussed.

Myomectomy during the first trimester associated with fetal limb anomalies and hydrocephalus in a twin pregnancy

OBJECTIVES

To present the complications of a twin pregnancy after first trimester myomectomy and to discuss the possible etiologic relationship.

CASE REPORT

A 44-year-old primigravida with a dichorionic-diamniotic twin pregnancy underwent myomectomy in another hospital at 12 weeks' gestational age. At 28 weeks the patient was referred to our unit because of ventriculomegaly and limb anomalies in the second twin. The patient underwent a Caesarean section at 37 weeks of gestation delivering twin A, a healthy female weighing 3235 g and twin B, a female weighing 2810 g with hydrocephalus and limb anomalies (clubfeet and hypoplasia of the nails and terminal phalanges). The placenta from twin A was normal, but in the placenta of twin B haemorrhage, thrombosis and infarction were noted.

CONCLUSIONS

Despite several reports of myomectomy in pregnancy without any problems for mother and fetus, the authors believe that myomectomy - especially in the first trimester - may be associated with the type of problems observed in the present case. The pathophysiological relationship between placental trauma and haemodynamic alterations as a possible cause of the malformations in twin B is discussed.

Two case reports of rare fetal tumors: an indication for surface rendering?

Fetal tumors are rare and can be difficult to diagnose in utero. This report describes one case of an extrarenal rhabdoid tumor and one case of a giant congenital melanocytic nevus. Both presented with moderate polyhydramnios and were prenatally detected at 31 weeks of gestation with two-dimensional ultrasound. The application of the surface mode of three-dimensional ultrasound improved the visualization of these tumors especially for the parents and the multidisciplinary team. Three-dimensional sonography proved to be a valuable addition to the prenatal armamentarium for the evaluation of these fetal tumors although it is not mandatory for their assessment and clinical management.

[Prenatal diagnosis and management in VACTERL association]

In terms of the VACTERL-Association we are dealing with a non-random association of malformations following a defect during mesodermal development of embryogenesis due to a variety of causes. We report on three cases with VACTERL-type malformations diagnosed by prenatal ultrasound presenting cardial defects, renal abnormalities, single umbilical arteries and esophageal stenosis. We present sonographical, clinical and autopsy findings and discuss the pathogenesis of VACTERL-Association as a defect of mesenchymal development in early embryogenesis.

[Ultrasound indications of fetal chromosome abnormalities in the 2nd trimester]

The most common fetal chromosomal disorders have structural abnormalities, which can be detected during second trimester ultrasound examination. Major malformations, also known as hardmarkers, when single or in combination, should raise the suspicion for a specific syndrome. But it is known, that even more subtile findings can increase the background risk based on the maternal age, especially for Down syndrome. A combination of these so called "soft-markers" can be used for second trimester screening in a high and low risk population. Here were report on the sonographic features of the common chromosomal anomalies and their significance in prenatal diagnosis.

Spontaneous fetal loss rates in a non-selected population

The objective of this work was to determine the rate of spontaneous fetal loss up to 28 weeks of gestation in uncomplicated pregnancies of a low-risk population after sonographically identified intact intrauterine pregnancy during the first trimester. Transvaginal ultrasounds were given to 2,534 women at between six and 12 weeks of gestation. Inclusion criteria were a positive fetal cardiac activity and no antecedent signs of vaginal bleeding. Gestational age was confirmed by measurement of the crown-rump length and/or biparietal diameter (BIP). Patients were followed until delivery or up to a fetal loss. The mean fetal loss rate between 12 and 28 weeks was 3.86% (n = 99). Fetal loss increased with maternal age: fetal loss rate under 20 yr: 2.94% (OR 0.75; CI 0.23-2. 46), 20-24 yr: 3.20% (OR 0.77; CI 0.48-1.23), 25-29 yr: 3.39% (OR 0.77; CI 0.50-1.19), 30-34 yr: 3.89% (OR 1.01; CI 0.59-1.71), 35-39 yr: 7.82% (OR 2.13; CI 1.04-4.32), 40-45 y: 50% (OR 13.84; CI 6.67-28.72) and > 45 yr: 50% (OR 13.05; CI 1.96-86.71) respectively. The frequency of spontaneous fetal loss before 28 weeks gestation was assessed systematically in a low-risk population. There was a very clear correlation with advancing maternal age. These data now can be used as background loss rate information for evaluating the safety of invasive prenatal diagnosis, and they will be more valid for this purpose than the available data taken from selected cohorts of women, such as those from hospital clinics or from infertility programs.

[Use of 3-dimensional ultrasound for assessment of intrauterine device position]

AIM OF THE STUDY

The purpose of our prospective study was to assess the accuracy of measuring and visualizing different types of IUDs with three dimensional ultrasound (3D) and two dimensional ultrasound (2D).

METHODS

Ultrasound investigation was carried out in 147 patients 6 weeks after insertion of the IUD; in 127 cases a copper IUD was inserted, in 20 cases a Levonorgestrel-containing (LNG) IUD. Correct measurement was defined as the distance between top of the IUD and inner endometrium as well as IUD and myometrium (fundus) in the longitudinal plane (2D) plus the frontal plane (3D). The possibility to visualize the complete IUD was evaluated in the frontal plane and in the transparent mode after volume rendering.

RESULTS

The distance measurement between copper IUD and myometrium or endometrium with 2D and 3D did not differ significantly (19.54 mm +/- 6.13 vs. 19.48 +/- 6.39, 5.58 +/- 4.57 vs. 5.21 +/- 4.57). There was no difference in the distance between LNG IUD and myometrium between the two ultrasound investigations (17.75 +/- 3.70 vs. 16.80 +/- 4.65), whereas the distance between LNG IUD and endometrium was significantly different (5.00 +/- 2.81 vs. 4.30 +/- 3.06, p = 0.03). The imaging of the LNG IUD was very clear with the 3D facilities, especially in the transparent mode. Furthermore, congenital anomalies of the uterus, like an arcuate uterus, were clearly detectable in the frontal plane (3D).

CONCLUSION

Distance measurement can be obtained equal as well by 2D or 3D ultrasound. The 3D ultrasound offers the advantage of better visualization of LNG IUD and the assessment of anomalies of the uterine cavity.

Fanconi anemia associated with increased nuchal translucency detected by first-trimester ultrasound

Increased nuchal translucency between 10 and 14 weeks of gestation has now been established as a marker for chromosomal defects in several large-scale studies. In addition, a growing number of structural defects and some rare genetic syndromes have been identified in association with this marker. We describe a case of a fetus with increased nuchal translucency at 12 weeks of gestation, in which second-trimester evaluation by ultrasound showed an enlarged cisterna magna, a ventricular septal defect and moderate signs of dysmorphia. Karyotyping by chorionic villus sampling revealed a high rate of chromosomal breaks. The diagnosis of Fanconi anemia with early onset was confirmed following the development of severe postnatal anemia 2 months after birth.

Increased nuchal translucency in a case of long-chain 3-hydroxyacyl- coenzyme A dehydrogenase deficiency

We present a case where the embryo showed an increased nuchal edema and a metabolic disorder. At 31 weeks of gestation the fetus developed a cardiomegaly and a hydrops. In this case, a long-chain 3-hydroxacyl-coenzyme A dehydrogenase deficiency (LCHAD deficiency) was confirmed by biochemical investigations in cultured chorionic villus cells and by DNA analysis. This metabolic disease causes a reduced production of mitochondrial trifunctional proteins and is a very rare autosomal-recessive disease.