Gerhard Bernaschek

Magnetic resonance imaging and ultrasound in the assessment of the fetal central nervous system.

Abstract Ultrasound is the screening modality of choice for evaluation of the fetal central nervous system (CNS). However, in cases of difficult diagnosis further fetal investigation is desirable. Due to ultrafast magnetic resonance imaging (MRI) techniques artifacts from fetal motions are minimized. MRI involves no exposure to radiation and hence appears to be safe. Due to the better soft tissue contrast, additional investigation by MRI may extend the sonographic diagnosis of fetal CNS-anomalies. Ultrasound and MRI are complementary imaging methods in the evaluation of the fetal CNS. The most important indications for ultrasound are screening for CNS anomalies and serial assessment of the dynamic of the disorder. The most important indications for fetal MRI are the “second opinion” and investigation by fetal MRI instead of postpartum MRI (especially in cases of planned postpartum intervention). In this article the indications and limitations of ultrasound and magnetic resonance imaging in the evaluation of the fetal CNS are discussed.

Three-dimensional ultrasonographic imaging of fetal tooth buds for characterization of facial clefts

The purpose of this prospective study was to investigate whether the antenatal characterization of fetal facial clefts can be improved by three-dimensional ultrasonographic visualization of fetal tooth buds. Between January 1996 and June 1998, seventeen consecutive fetuses with facial clefts were examined for fetal maxillary tooth buds in the cleft area using three-dimensional multiplanar reconstruction. It was possible in all cases to classify the clefts either as cleft lip alone or unilateral cleft lip and palate or bilateral cleft lip and palate. Three-dimensional computed tomography and histological jaw sections of three stillborn infants were produced in order to examine the correlation between the sonographic, radiographical and histological findings. The prenatal characterization of the facial clefts by means of a visualization of the tooth buds showed to be accurate postnatally in all cases. The sonographic proof of tooth buds might gain increasing importance as this technique seems to facilitate and improve the prenatal classification of suspected facial clefts.

Antepartum fetal and maternal carboxyhemoglobin and cotinine levels among cigarette smokers

The objective of this study was to examine the association of carboxyhemoglobin (COHb) and plasma cotinine levels among pregnant women who smoke cigarettes and their fetuses. Fifteen pregnant women who smoked and their fetuses undergoing cordocentesis had blood samples analysed simultaneously for COHb and cotinine. Linear regression was used to test for associations among study variables. Significant maternal‐fetal associations were observed both with COHb (r= 0.72, p= 0.003) and with cotinine (r= 0.96, p= 0.003). Maternal cotinine levels were correlated with maternal and fetal COHb levels (r= 0.96, p= 0.003; r= 0.99, p= 0.0003, respectively). Fetal cotinine levels were correlated with COHb in maternal and in fetal blood (r= 0.81, p= 0.0003; r= 0.88, p < 0.0001, respectively). The strong direct associations of maternal and fetal levels of COHb and cotinine indicate that maternal COHb and cotinine measurements may be interpreted as surrogates of fetal COHb levels. However, the specificity, ex vivo stability and ease of measurement of cotinine offer advantages over using COHb in quantifying fetal CO exposure following maternal cigarette smoking.

Fetal and early postnatal magnetic resonance imaging – is there a difference?

Abstract Aim: To evaluate whether fetal magnetic resonance imaging (MRI) could replace early postnatal MRI in fetuses with central nervous system (CNS) anomalies. Methods: Thirteen pregnancies presenting with fetal CNS anomalies were investigated using MRI. Indications included ventriculomegaly combined with additional CNS anomaly (n=5), isolated ventriculomegaly (n=2), arachnoid cyst (n=2), holoprosencephaly (n=1), complex malformation syndrome (ns1), Dandy walker malformation (n=1) and midline cyst (n=1). Early postnatal MRI followed within the first six weeks of life. Results: Investigation with early postnatal MRI confirmed the fetal MRI diagnosis in all cases. Investigation with postnatal MRI presented additional information in two cases. However, there was no change in patient care. Conclusions: Fetal MRI should replace early postnatal MRI in infants with CNS anomalies.

A Fetus with Trisomy 9p and Trisomy 10p Originating from Unbalanced Segregation of a Maternal Complex Chromosome Rearrangement t(4;10;9)

Complex chromosome rearrangements are only rarely seen in constitutional karyotypes. A case of prenatally detected trisomy 9p with trisomy 10p originating from adjacent segregation of a maternal complex chromosome rearrangement is reported. Ultrasound examination at 18 weeks of gestation showed cleft lip palate, club feet, structural anomalies of the cerebellum and cystic kidneys. Cytogenetic analysis of amnion cells revealed a female fetus with 47,XX,+der(9). FISH analyses together with parental karyotyping demonstrated the fetal additional chromosome to originate from malsegregation of a maternal complex chromosomal rearrangement. The mother is carrier of a balanced translocation t(4;10;9) (q12; p11;q13). Postmortem examination of the fetus showed nose anomalies, cleft lip palate, low set ears, club feet, lung anomalies, cystic kidney and aplasia of the uterus. Reporting of such rare cases is important in order to enable this information to be used for genetic counselling in similar situations.

Endosonography in obstetrics and gynecology

History of Endosonography.- References.- Safety Aspects of Endosonography.- 1 Biologic Effects of Ultrasound.- 1.1 Thermal Effects.- 1.2 Cavitation.- 1.3 Chromosome Damage.- 1.4 Sister Chromatid Exchange Rate.- 1.5 Epidemiologic Studies.- 1.6 Carcinogenesis.- 1.7 Statistical Considerations.- 1.8 Summary.- 2 Sterilization of Vaginal Probes.- References.- Advantages and Disadvantages of Endosonography.- 1 Advantages.- 2 Disadvantages.- Scanner Types.- 1 Linear-Array Scanners.- 2 Curved-Array Scanners.- 3 Sector Scanners.- Scan Planes.- 1 Definition of Scan Directions.- 2 Definition of Scan Planes.- Orientation of Scan Planes.- Reference.- Endosonographic Procedures.- 1 Vaginosonography.- 2 Hysterosonography.- 3 Rectosonography.- 4 Cystosonography.- References.- Normal Early Pregnancy.- 1 Chorionic Cavity.- 1.1 General.- 1.2 Vaginosonography.- 1.3 Recognition of Pseudogestational Sac.- 1.4 Correlation Between Chorionic Cavity and ss-hCG.- 1.4.1 Earliest Detection with Vaginosonography.- 1.4.2 Discriminatory Limit.- 2 Yolk Sac.- 2.1 General.- 2.2 Vaginosonography.- 3 Embryo.- 3.1 General.- 3.2 Vaginosonography.- 4 Cardiac Activity.- 4.1 General.- 4.2 Vaginosonography.- 5 Amniotic Cavity.- 5.1 General.- 5.2 Vaginosonography.- 6 Other Biometrie Data in the First Trimester.- 6.1 Biparietal Diameter.- 6.2 Trunk Diameter.- 6.3 Umbilical Cord and Placenta.- 7 Multiple Pregnancy.- 8 Summary.- References.- Disorders of Early Pregnancy.- 1 General.- 2 Threatened Abortion.- 3 Blighted Ovum.- 4 Missed Abortion.- 5 Incomplete Abortion.- 6 Hydatidiform Mole.- 7 Ectopic Pregnancy.- 7.1 General.- 7.2 Exclusion of Intrauterine Pregnancy.- 7.2.1 Recognition of a Pseudogestational Sac.- 7.2.2 Discriminatory Limit.- 7.3 Demonstration of an Intact Ectopic Pregnancy in the Adnexal Region.- 7.4 Nonspecific Masses in the Adnexal Region.- 7.5 Free Fluid in the Abdomen.- 7.6 Uncommon Sites of Ectopic Pregnancy.- 7.7 Summary.- References.- Vaginosonographic Examination of the Fetus.- 1 General.- 2 Indications.- 2.1 Examination of the Fetus in the First Half of Pregnancy.- 2.1.1 Biometry.- 2.1.2 Visualization of Fetal Organs.- 2.1.3 Screening for Anomalies.- 2.1.4 Anhydramnios.- 2.1.5 Sex Determination.- 2.1.6 2.2 Examination of the Fetus in the Second Half of Pregnancy.- 2.2.1 Examination of the Presenting Part.- 2.2.2 Vaginal Pulsed Doppler Examination of Fetal Arteries.- References.- Evaluation of the Cervix.- 1 General.- 2 Vaginosonography.- References.- Placenta Previa.- 1 General.- 2 Vaginosonography.- 3 Summary.- References.- Vaginosonographic Pelvimetry.- 1 General.- 2 Technique and Preliminary Results.- 3 Summary.- References.- Endosonography of the Uterus.- 1 Normal Anatomy.- 1.1 Size.- 1.2 Version and Flexion.- 2 Congenital Anomalies.- 3 Diagnosis of Myomas.- References.- Endosonography of the Ovaries.- 1 The Normal Ovary.- 2 Ovarian Cysts.- 2.1 Corpus Luteum Cysts.- 2.2 Dermoid Cysts.- 2.3 Endometriotic Cysts.- 2.4 Multiloculated Cysts.- 2.5 Ovarian Carcinoma.- 3 Inflammatory Adnexal Changes.- References.- Postoperative Endosonography.- References.- Intrauterine Contraceptive Devices.- 1 General.- 2 Vaginosonography.- References.- Endosonographic Diagnosis of Carcinoma.- 1 Cervical Carcinoma.- 1.1 General.- 1.2 Staging.- 1.2.1 Rectosonography Vs Vaginosonography.- 1.2.2 Intracervical Extent of Disease.- 1.2.3 Vaginal Infiltration.- 1.2.4 Parametrial Infiltration.- 1.2.5 Infiltration of the Bladder Wall and Rectum.- 1.2.6 Comparison of CT, MRI, and Endosonography.- 1.3 Follow-up of Inoperable Cervical Carcinoma.- 2 Corpus Carcinoma.- 2.1 General.- 2.2 Early Detection.- 2.3 Staging.- 2.3.1 Hysterosonography.- 2.3.1.1 Carcinoma Confined to the Endometrium.- 2.3.1.2 Myometrial Invasion.- 2.3.1.3 Extension to the Cervix.- 2.3.2 Vaginosonography.- 2.4 Summary.- 3 Ovarian Carcinoma.- 3.1 General.- 3.2 Early Detection.- 4 Vaginal Carcinoma.- 5 Diagnosis of Recurrent Carcinoma.- 5.1 General.- 5.2 Detection of Recurrence.- References.- Diagnostic Evaluation of Urinary Incontinence.- 1 General.- 2 Vaginosonography and Rectosonography.- 3 Perineal and Introital Sonography.- References.- Infertility.- 1 General.- 2 Evaluation of the Menstrual Cycle.- 2.1 General.- 2.2 Visualization and Measurement of the Follicles.- 2.3 Corpus Luteum.- 2.4 Cyclic Endometrial Changes.- 2.5 Correlation of Folliculometry with Hormonal Parameters.- 2.6 Doppler Measurements of Blood Vessels in the Lesser Pelvis.- 3 Endocrine Disorders.- 3.1 Corpus Luteum Insufficiency.- 3.2 LUF Syndrome.- 3.3 PCO Syndrome.- 4 In Vitro Fertilization.- 4.1 General.- 4.2 Stimulation Therapy.- 4.3 Determining the Time of Ovulation.- 4.4 Inadequate Stimulation Therapy.- 4.4.1 Hyperstimulation.- 4.4.2 Insufficient Stimulation.- 4.5 Follicular Aspiration.- 4.5.1 Laparotomy and Laparoscopy.- 4.5.2 Ultrasound-Guided Aspiration Methods.- 4.5.3 Vaginal Follicular Aspiration Guided by Vaginosonography.- 4.6 Embryo Transfer.- 5 Summary.- References.- Endosonographically Guided Punctures.- 1 General.- 2 Technical Aspects.- 2.1 Scanner Types.- 2.2 Freehand Needle Technique.- 2.3 Needle Guides.- 2.4 Preparation of the Patient.- 3 Indications.- 3.1 Follicular Aspiration.- 3.1.1 General.- 3.1.2 Vaginal Follicular Aspiration Guided by Vaginosonography.- 3.2 Aspiration of Cysts.- 3.2.1 Cyst Wall Biopsy.- 3.2.2 Sclerotherapy.- 3.2.3 Abscess Drainage.- 3.3 Puncture of Tubal Pregnancy.- 3.4 Selective Embryocide.- 3.4.1 General.- 3.4.2 Ultrasound-Guided Embryocide.- 3.5 Fine-Needle Aspiration Biopsy.- 3.6 Chorionic Biopsy.- 3.6.1 General.- 3.6.2 Chorionic Biopsy Using a Vaginal Scanner.- 3.7 Vaginal Decompression of Hydrocephalus.- References.- Vaginal Doppler Techniques.- 1 Basic Principles of Doppler Ultrasound.- 2 Vaginal Probes.- 2.1 Continuous Wave Doppler.- 2.2 Pulsed Doppler.- 2.3 Doppler Waveforms.- 3 Vaginal Pulsed Doppler Techniques.- 3.1 Examination Procedure.- 3.2 Advantages of Vaginal Doppler.- 4 Clinical Applications.- 4.1 The Uterine Artery.- 4.1.1 Normal Pregnancy.- 4.1.2 Complicated Pregnancy.- 4.2 Fetal Vessels.- 4.2.1 Early Pregnancy.- 4.2.2 The Fetal Internal Carotid Artery.- 4.3 Uterine Artery Flow in Cervical Carcinoma.- 4.4 Infertility.- 4.4.1 Failure of Implantation After Embryo Transfer.- 4.4.2 The Ovarian and Iliac Arteries in Stimulated Cycles.- 5 Clinical Significance of Vaginal Pulsed Doppler Blood Flow Studies.- References.- Subject Index 183.

Endosonographically Guided Punctures

Culdocentesis was an important diagnostic procedure before the advent of laparoscopy, but its importance has diminished with routine use. Before the advent of vaginosonographically guided follicular aspiration, endosonography played only a minor role as a means of directing invasive procedures in gynecologic patients, although some attempts were made to obtain cytologic or histologic confirmation of pelvic wall recurrence of cervical cancer using an endosonographically guided needle. The use of vaginosonography to demonstrate structures in the lesser pelvis has shown that a needle inserted vaginally must travel only a short distance to reach the ovaries. Because the ovaries are usually located very close to the vaginal wall in the region of the cul-de-sac, the vaginal approach offers an obvious solution to the problem of the “long-distance” aspiration.

Association of fetal and maternal carboxyhemoglobin levels in normal and Rh-alloimmune pregnancies

OBJECTIVE To compare paired antepartum fetal/maternal COHb ratios in whole blood from control and alloimmunized pregnancies and to examine the relationships between fetal and maternal COHb. METHODS COHb levels were measured in paired fetal and maternal blood samples obtained at cordocentesis in 47 control and 16 Rh-alloimmunized pregnancies. COHb was determined by gas chromatography. Results were analyzed by t-test, regression and analysis of covariance. RESULTS Although fetal/maternal COHb ratios for control and alloimmunized pregnancies were not statistically significantly different, i.e. 1. 11+/-0.04 and 1.26+/-0.09, respectively (P=0.09), fetal COHb levels were higher in Rh-alloimmunized fetuses (P=0.0002). Fetal COHb levels were also higher than paired maternal levels among the alloimmunized group (P=0.011), but not among the control group (1. 04+/-0.04, P=ns). In univariate regression analysis, fetal and maternal COHb levels were significantly correlated with one another in both control (r=0.52, P=0.0002) and alloimmunized pregnancy groups (r=0.52, P=0.05). Comparison of the slopes of the fetal versus maternal COHb plots for the two groups showed a significant difference (P=0.02), with the alloimmunized group having the steeper slope. CONCLUSION Differences in the antepartum fetal-maternal COHb relationships in control and alloimmunized groups likely reflect increased endogenous CO production among alloimmunized fetuses as a result of pathologic hemolysis.

Vaginal Doppler Techniques

The Doppler effect, named for the Austrian physicist Christian Johann Doppler, is based on the fact that all wave phenomena, including sound and light, undergo a change of frequency and wavelength when the source of the wave and the observer are moving relative to each other. In acoustics, the number of sound vibrations that reach the listener per unit time change according to whether the sound source is moving toward or away from the listener. The original basis on which Doppler formulated his law — the color change observed in distant, receding stars (Doppler 1843) — applies with equal validity to acoustic waves (Buys Ballot 1845).

Disorders of Early Pregnancy

Bleeding and cramping are among the most fequent complications of pregnancy in the first trimester. Since clinical and laboratory studies are unable to establish the integrity of the pregnancy or the viability of the fetus with absolute confidence, sonography provides the only means of assigning a specific diagnosis to the initially nonspecific symptoms. Moreover, the prognostic value of ultrasound in this situation can be a great comfort to the patient who has learned little from hormone tests and pelvic examinations but is alarmed and distressed by her symptoms. Given the lack of acceptance of early ultrasound screening at many centers, it is rare for an abnormal pregnancy to be recognized in the first trimester before clinical symptoms have appeared.