Intrathoracic fluid may be a normal finding at around 8 gestational weeks.

OBJECTIVE: To describe the observation of embryonic thoracic fluid at around 8 weeks' gestation and to discuss the likely etiology. METHODS: This was a retrospective study of patients referred between August 2005 and May 2006 to our units in France and in the USA for a dating scan between 6 and 10 weeks. Included in our series were all embryos presenting with an ultrasound finding suggestive of an early pericardial fluid collection, i.e. a large anechoic fluid collection surrounding the heart. The gestational age, fetal heart rate and maternal age at this first scan were recorded, along with nuchal translucency thickness as measured at the 12-week scan and the second-trimester anomaly scan results. RESULTS: Five cases were included in this study. In all five patients, the anechoic fluid collection was visualized at 8 weeks, and by the time of the nuchal scan it had disappeared completely. The nuchal translucency thickness was normal in all cases and all five embryos had normal cardiac examinations during the second trimester and were normal at birth. CONCLUSIONS: The observation on ultrasound at 8 weeks' gestation of a large anechoic fluid collection surrounding the heart that disappears by week 12 is suggestive of a transient pericardial collection.

Prenatal diagnosis of wormian bones.

The prenatal diagnosis of wormian bones has not been made previously. We report four fetuses with wormian bones but none of the associated anomalies. The diagnosis, differential diagnosis, associated anomalies, and prognosis of this entity are discussed.

Air-contrast sonohysterography as a first step assessment of tubal patency.

We assessed the use of air as a sonographic contrast agent in the investigation of tubal patency by sonohysterography. We examined 115 women assessed for infertility. After saline sonohysterography, small amounts of air were insufflated, and the tubal passage of bubbles was monitored. In five patients (excluded from the results), cervical stenosis prevented the procedure. Ninety-one tubes (right side) and 86 tubes (left side) were definitively patent; 5 and 7, respectively, were probably patent; and 12 and 16, respectively, were nonvisualized. Nine patients had polyps, 3 had synechiae, and 2 had submucosal fibroids. None of the patients had infectious complications. Air-sonohysterography and laparoscopy with chromopertubation showed agreement in 79.4%. In 17.2% of patients, the tubes were considered nonvisualized by air-sonohysterography when they were patent. The sensitivity was 85.7% and specificity 77.2%. In conclusion, air-sonohysterography is a comfortable, simple, and inexpensive first line of tubal patency investigations yielding high accuracy.

Prenatal diagnosis of alobar holoprosencephaly at 10 weeks of gestation.

Alobar holoprosencephaly is an intracranial abnormality characterized by failure of proper cleavage of the prosencephalon, accompanied by incomplete midfacial development. The prenatal sonographic diagnosis of alobar holoprosencephaly was first described in 1984; however, there have been only two reports of alobar holoprosencephaly diagnosed in the first trimester. We report a case of alobar holoprosencephaly diagnosed at 10 weeks of gestation.

The accuracy of prenatal ultrasonography in detecting congenital anomalies.

OBJECTIVES: The purpose of this study was to evaluate the accuracy of prenatal ultrasonography in detecting congenital anomalies. STUDY DESIGN: We studied all singleton births or fetal deaths with one or more congenital defects delivered during the study period who had had one or more ultrasonographic examinations performed at or after 16 weeks' gestation and a random sample of defect-free newborns similarly examined by ultrasonography. Congenital anomalies reported on either the infants' postdelivery medical record or the fetal autopsy report were our standard. Prenatal ultrasonographic findings reported during gestation and therefore "blind" to the postdelivery outcome were then compared with the standard. RESULTS: The overall sensitivity of ultrasonography in detecting defects was 53%. The overall specificity was 99%. Ultrasonography proved to be highly sensitive (89%) for prevalent lethal malformations. However, serious cardiac defects, microcephalus, and many musculoskeletal deformities were missed by ultrasonography. CONCLUSION: Ultrasonography is sensitive in detecting many lethal malformations. However, a negative prenatal ultrasonographic examination does not provide absolute assurance that a fetus is defect free.

Fetal biometry of skeletal dysplasias: a multicentric study.

Twenty-three diagnostic centers worldwide contributed 127 cases of 17 skeletal dysplasias. Discriminant analysis showed that the femur length was the best biometric parameter to distinguish among the five most common disorders in this series (thanatophoric dysplasia, osteogenesis imperfecta type II, achondrogenesis, achondroplasia and hypochondroplasia). Fifty-four percent of fetuses with femur length below 30% of the mean for gestational age had achondrogenesis. Seventy-eight percent of measurements between 40 and 60% of the mean for gestational age represented either thanatophoric dysplasia or osteogenesis imperfecta type II. Fetuses who had over 80% of the mean for gestational age had predominantly hypochondroplasia, achondroplasia, and osteogenesis imperfecta type III.

Fetal biometry of skeletal dysplasias: a multicentric study.

Twenty-three diagnostic centers worldwide contributed 127 cases of 17 skeletal dysplasias. Discriminant analysis showed that the femur length was the best biometric parameter to distinguish among the five most common disorders in this series (thanatophoric dysplasia, osteogenesis imperfecta type II, achondrogenesis, achondroplasia and hypochondroplasia). Fifty-four percent of fetuses with femur length below 30% of the mean for gestational age had achondrogenesis. Seventy-eight percent of measurements between 40 and 60% of the mean for gestational age represented either thanatophoric dysplasia or osteogenesis imperfecta type II. Fetuses who had over 80% of the mean for gestational age had predominantly hypochondroplasia, achondroplasia, and osteogenesis imperfecta type III.

Automatic measurements of fetal long bones. A feasibility study.

We investigated whether it would be possible for a computer to propose values for measurements commonly obtained (femur and humerus) during obstetrical sonography. In this preliminary study, the images were scanned and analyzed off-line using morphological operators. The procedure described allowed us to measure the long bones and has a very high coefficient of correlation with measurements obtained by humans. Ideally, the whole procedure could probably be part of the computer instructions that are built into the machine.

Pitfall in the diagnosis of nuchal cystic hygroma.

We present a case of spontaneous resolution of a nuchal cystic hygroma in a fetus with a normal karyotype. This unusual case is important in the counseling of patients with affected fetuses, since the transitory nature of the disease is not well known.

Prenatal diagnosis of fetal cephalocele: a sonographic spectrum.

We present the findings in a series of 15 fetuses diagnosed as having a cephalocele. Eleven cephaloceles were located in the occipital region and two each at the vertex and the frontonasal region. Eleven fetuses were diagnosed before 24 week's gestation. Nine families opted for an interruption. Of the two fetuses that went to term, one had a benign meningocele and is growing normally at 18 months, the other died in the neonatal period of associated cardiac anomalies. Of the four fetuses diagnosed after 24 weeks, one is normal (after surgery) at 9 months, two are severely handicapped, and one died in the immediate postpartum period.

Automatic segmentation of ultrasound images using morphological operators.

A method for the automatic measurement of femur length in fetal ultrasound images is presented. Fetal femur length measurements are used to estimate gestational age by comparing the measurement to a typical growth chart. Using a real-time ultrasound system, sonographers currently indicate the femur endpoints on the ultrasound display station with a mouse-like device. The measurements are subjective, and have been proven to be inconsistent. The automatic approach described exploits prior knowledge of the general range of femoral size and shape by using morphological operators, which process images based on shape characteristics. Morphological operators are used first to remove the background (noise) from the image, next to refine the shape of the femur and remove spurious artifacts, and finally to produce a single pixel-wide skeleton of the femur. The skeleton endpoints are assumed to be the femur endpoints. The length of the femur is calculated as the distance between those endpoints. A comparison of the measurements obtained with the manual and with the automated techniques is included.

Persistent right umbilical vein: an ominous prenatal finding?

The persistence of a right umbilical vein is an uncommon finding, with only a dozen cases reported since 1826. The persistent right umbilical vein may replace the normal left umbilical vein or be supernumerary. The anomaly is associated with numerous and occasionally lethal malformations. In this series, only three of six fetuses (and another two in the literature) had no associated anomalies. All the others had a variety of associated lesions ranging from minor to lethal. The appearance at ultrasound is easy to recognize: The intrahepatic portion of the umbilical vein is lateral to the gallbladder, and the portal vein curves toward the stomach, instead of parallel to it. Since the recognition of the persistent right umbilical vein is simple and does not require additional scanning (it is visible in the section used to measure the abdominal perimeter), the author suggests using it as an indicator for more in-depth scanning.

Prenatal diagnoses in unilateral empty renal fossa.

Six cases of unilateral empty renal fossa diagnosed by obstetric sonography are described. The anomalies reported (ectopic kidney, cross-fused ectopic kidney, and unilateral renal agenesis) have not yet been described in the prenatal literature, to our knowledge, in fetuses that are otherwise normal. The study also demonstrates that, in spite of their nonvital in utero role, single kidneys may show compensatory hypertrophy.

Single-needle insertion in twin amniocentesis.

Amniocentesis in twin gestation is an uncommon event for most medical centers. The current technique used for this procedure includes two or more needle insertions and the introduction of dye into the first sac. A new approach that consists of a single insertion is proposed. The advantages of this alternate technique are that it requires only one insertion, it is a swifter procedure, it does not require the injection of dye, and it offers positive proof of tapping the two gestational sacs. Although this technique may have some potential risks, in our judgment the advantages outweight the potential risks, and this technique should be considered and its feasibility evaluated in cases of twin gestation requiring two-sac tapping.

In utero detection of cardiac failure from an aneurysm of the vein of Galen.

The detection of a vein of Galen aneurysm in a hydrocephalic fetus is presented. The differential diagnosis for the midline cystic structure was made on the basis of the presence of high-velocity flow on Doppler ultrasonographic examination.

Cordocentesis for rapid karyotyping.

Pure fetal blood was obtained by cordocentesis in 101 fetuses of 96 patients at 15 to 38 weeks' gestation. Rapid karyotype was obtained within 2 to 4 days by fetal lymphocyte culture. Chromosomal abnormality was detected in 12 (11.9%) fetuses. Abnormal karyotype was found in 5 of 44 fetuses with structural malformations, 3 of 13 fetuses with intrauterine growth retardation or oligohydramnios, 1 of 3 fetuses with nonimmune hydrops fetalis, 2 (one monozygotic set) of 10 discordant twins, 1 of 12 isoimmunized gestations, none of 8 cases with advanced gestational-maternal age, and none of 6 immune thrombocytopenia cases. This suggests that rapid karyotype should be obtained in all cases of fetal structural malformations, intrauterine growth retardation, and nonimmune fetal hydrops, and may be obtained incidentally in isoimmunized pregnancies and discordant twins to assist in clinical management.