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Biomedical subjects

K D Kalache

Publications and source records attributed to K D Kalache.

At least 19 recordsLinked to original sources
PubMed2005

Outcome of 60 neonates who had ARED flow prenatally compared with a matched control group of appropriate-for-gestational age preterm neonates.

OBJECTIVE: To describe the course and outcome of fetuses with absent or reversed end-diastolic (ARED) flow in the umbilical artery (UA) and to examine the influence of prematurity according to gestational age at delivery. METHODS: Sixty pregnancies complicated by ARED flow in the UA were monitored by repeat Doppler measurements of arterial and venous vessels, non-stress tests (cardiotocogram (CTG)) and maternal investigations, and were delivered between 24 and 34 weeks. Fetal outcome was investigated and compared to a control group of appropriate-for-gestational age (AGA) preterm neonates, matched for gestational age. Mortality, birth weight, Apgar scores, postnatal cord arterial pH and need for ventilation were all recorded, as were cases of respiratory distress syndrome, bronchopulmonary dysplasia, persistent ductus arteriosus, necrotizing enterocolitis, intraventricular hemorrhage, periventricular leukomalacia, abnormal neurological findings and those requiring surgical intervention. Additionally, the group of fetuses with ARED flow was divided into three subgroups of different degrees of prematurity (delivery between 24 + 0 and 28 + 6 weeks, delivery between 29 + 0 and 31 + 6 weeks, and delivery after 32 weeks) and compared according to the above parameters. RESULTS: Pre- or postnatal death occurred in 16 cases. Comparing the 44 (61%) that were born alive with the AGA neonates, significant differences were found in birth weight (P < 0.001), arterial pH value (P < 0.001), bronchopulmonary dysplasia (P = 0.002) and intestinal complications (P < 0.01). Prematurity-related complications were: need for ventilation (P = 0.001), respiratory distress syndrome (P < 0.0001), periventricular leukomalacia (P = 0.002) and pathological neurological testing (P = 0.005). CONCLUSIONS: Neonates displaying ARED flow before birth are growth restricted, acidemic at delivery and are at high risk of developing bronchopulmonary dysplasia and intestinal complications. While perinatal mortality seems to be related to abnormal fetal Doppler velocimetry, age at delivery has a significant impact on short-term morbidity. After 32 weeks, morbidity is low and delivery should be considered. It could be speculated from our data that prolongation of pregnancy with Doppler velocimetry monitoring could help to reduce morbidity, although prolongation remains limited in most cases.

Birth Weight↗
PubMed2004

Prenatal sonographic features of a rhabdoid tumor of the kidney.

Rhabdoid tumors of the kidney are highly lethal malignancies of infancy. We report the prenatal detection of a renal rhabdoid tumor with mesoblastic components in a fetus at 27 weeks of gestation. The tumor presented as a large mass in the left renal area and there was concomitant massive polyhydramnios. Though the sonographic features alone did not allow distinction from a benign lesion, the aggressive tumor growth indicated malignancy. Amniotic fluid cytology was performed but failed to confirm the diagnosis. Corticosteroids were administered for lung maturation. Tocolysis, including betamimetics, magnesium and indomethacin, was performed to prevent premature labor. Additionally, serial amniodrainage was performed. At 30 weeks of gestation fetal hydrops developed and a Cesarean section was performed. After delivery, ventilation of the preterm infant was insufficient due to diaphragm elevation by the huge tumor, requiring immediate tumor surgery. However, though ventilation was improved the infant died of cardiac failure 4 h after surgery.

Adult↗
PubMed2004

[Three-dimensional power Doppler ultrasonography (3D-PDU) in fetal diagnosis].

AIM: 3D power Doppler ultrasonography (3D-PDU) is a new method which allows the spatial presentation of fetal vessels in utero. In the presented study we have examined the feasibility of this technique in prenatal diagnosis. Aim of our pilot study with normal human fetuses was to determine the adjustment of the system presets, the optimal insonation planes and the regions of interest. MATERIAL AND METHODS: Seven regions of interest were examined in three different planes. The 3D volume was acquired by a free hand sweep. The feasibility of the method was quantitatively determined for every plane and region. For each of the three planes a total of 25 examinations was planned and the successful rate per region of interest was then assessed for the total of these 75 examinations. In a two year period, a total number of 80 fetuses from 16 to 34 weeks' gestation could be enrolled in the study. RESULTS: Best examinations were achieved in the vessels of the umbilical cord (successful rate 100 %), followed by the placental and abdominal (84 % each), cerebral (80 %), pulmonary (64 %), and renal vessels (51 %). The most difficult conditions for examination and the most unreliable results were found for the fetal heart with a success rate of only 31 % of the cases. Similar to the experience in 2D power Doppler, a plane with blood flow towards the transducer was the best insonation plane. CONCLUSIONS: In our study we were able to show that a three dimensional demonstration of fetal vessels is possible with the system used. The feasibility is limited by fetal movements and unfavourable fetal positioning. The possible benefit of the method is to diagnose complex fetal vascular malformations in the future.

Female↗
PubMed2003

Caliber of the coronary sinus in fetuses with cardiac defects with and without left persistent superior vena cava and in growth-restricted fetuses with heart-sparing effect.

OBJECTIVE: To assess reference ranges for fetal coronary sinus (CS) diameter and to compare them with values from fetuses showing heart defects with and without left superior vena cava (LSVC) as well as with severe intrauterine growth retardation and heart-sparing effect on color Doppler. METHODS: The coronary sinus was visualized on two-dimensional ultrasound in a plane slightly caudal to the apical four-chamber view. For the normal range of the size of the CS in relation to gestational age, data was collected from 108/114 (95%) normal fetuses with good visualization between 20 weeks' gestation and term. Abnormal conditions comprised two groups: group 1 consisted of 52 fetuses with heart anomalies, including three subgroups: 11 fetuses with isolated LSVC emptying into the coronary sinus, 12 fetuses with LSVC associated with structural heart defects and 29 fetuses with structural heart defects but without LSVC. Group 2 consisted of 11 fetuses with severe intrauterine growth retardation and dilated coronary arteries as seen by color Doppler ultrasound. RESULTS: Under normal conditions, there was a significant increase in the CS diameter with advancing gestational age (1.2-2.7 mm). Significant dilatation was found only in the two groups with LSVC (range 2.7-6.5 mm), independent of whether the finding was isolated or associated with cardiac defects. CONCLUSION: CS visualization and measurements are easily feasible in the human fetus in the apical four-chamber view. Significant dilatation of the CS is a sign of LSVC. The examiner should be aware of this condition as such dilatation is commonly falsely diagnosed as atrial or atrioventricular septal defect.

Case-Control Studies↗
PubMed2003

Three-dimensional ultrasound fetal lung volume measurement: a systematic study comparing the multiplanar method with the rotational (VOCAL) technique.

OBJECTIVES: This study was designed to compare a conventional multiplanar technique for three-dimensional (3D) ultrasound measurement of fetal lung volume with a rotational method using VOCAL trade mark (Virtual Organ Computer-aided AnaLysis). METHODS: Thirty-two fetuses with a variety of conditions at risk for pulmonary hypoplasia were studied. 3D volume data sets of the fetal lungs were acquired using a commercially available ultrasound system. The right and left lung volumes were calculated separately using VOCAL and the multiplanar technique. The level of agreement between two independent observers in categorizing the 3D volume data set as measurable or non-measurable was determined. The interobserver and intermethod variabilities were also evaluated for both methods. RESULTS: The intermethod variability was excellent (correlation r = 0.93 and r = 0.96 for the left and right lung, respectively), and there was substantial agreement between the results of both approaches (limits of agreement - 4.4 to 8.9 and - 3.4 to 4.8 mL for the right and left lung, respectively). Fetal lung estimation with VOCAL had a significantly higher interobserver variability than the multiplanar technique. Interobserver agreement in categorizing lung volume data sets as measurable or non-measurable was lower when VOCAL was used. CONCLUSION: Fetal lung volume measurements can be undertaken interchangeably using the multiplanar technique or the rotational method with VOCAL. However, the latter was less reproducible (lower degree of agreement and significantly higher interobserver variability) than the former.

Female↗
PubMed2002

Absent or hypoplastic thymus on ultrasound: a marker for deletion 22q11.2 in fetal cardiac defects.

OBJECTIVE: Congenital heart defects (CHD), particularly conotruncal anomalies, may be associated with deletion of chromosome 22q11.2. Thymic aplasia or hypoplasia is known to be a typical feature in this condition. We aimed to establish (i) the prevalence of del22q11.2 in fetal CHD and (ii) whether ultrasound assessment of an absent or hypoplastic fetal thymus helps in preselection of a group who are at high risk for this deletion. STUDY DESIGN: In fetuses (> 16 weeks) with CHD, karyotyping and fluorescence in situ hybridization for 22q11.2 were offered and the fetal thymus was evaluated sonographically. RESULTS: One hundred and forty-nine fetuses with CHD and normal karyotype were analyzed. Seventy-six fetuses had conotruncal anomalies. 22q11.2 deletion was present in 10 cases (6.7%), all of which had conotruncal anomalies (13.1%). Thymic hypoplasia or absence was suspected in 11 cases with conotruncal anomaly. Nine of these 11 had the deletion; two cases were false positive. One fetus with a normal-sized thymus had deletion of 22q11.2 (sensitivity 90%, specificity 98.5%, positive predictive value 81.8%, and negative predictive value 99.2%). By subtype of cardiac anomaly, there was deletion in four of six fetuses with interruption of the aortic arch, two of four with absent pulmonary valve syndrome, three of nine with truncus arteriosus and one of 11 cases of tetralogy of Fallot. Pulmonary atresia with ventricular septal defect (n = 7), right-sided aortic arch (n = 4), transposition of the great arteries (n = 14), double outlet right ventricle (n = 13) and other complex malpositions of the great vessels (n = 8) were not associated with the deletion. CONCLUSION: Thymic hypoplasia or aplasia may reliably be diagnosed during fetal echocardiography. The technique allows identification of a group at high risk for 22q11.2 deletion and is more specific and sensitive than by subtype of cardiac anomaly alone.

Chromosomes, Human, Pair 22↗
PubMed2002

Does fetal tracheal fluid flow during fetal breathing movements change before the onset of labour?

OBJECTIVE: To examine changes in intra-tracheal fluid flow parameters during fetal breathing movements throughout the second half of pregnancy in the normally developing human fetus. DESIGN: Prospective cross-sectional study. SETTING: Fetal medicine unit at the Charité University Hospital in Berlin. METHODS: Assessment of tracheal fluid flow was attempted in 340 healthy fetuses (GA 20-40 weeks) in which fetal breathing movements were seen by B-mode scan. Colour Doppler was applied to visualise the tracheal fluid flow, followed by spectral Doppler to record the velocity waveforms. The records of 53 fetuses divided into five gestational age groups (20-23, 24-27, 28-31, 32-35 and 36-40 weeks of gestation) containing 40 or more continuous breathing cycles (inspiration and expiration) were considered for analysis. Only regular breathing phases were examined and the volume obtained by integration of the tracheal fluid flow displaced during fetal breathing movements was calculated. RESULTS: The intra-tracheal flow volume moved during inspiration (Vi) and expiration (Ve) increased until 36 weeks of gestation after which there was a flattening until term. This suggests either a reduction of lung liquid production or a diminished lung liquid volume. The median difference between Vi and Ve was positive in the first four age groups and negative in the last one suggesting that, in mature fetuses, the effect of fetal breathing movements no longer results in an influx. CONCLUSIONS: Our data demonstrate a modification in fetal behaviour that manifests itself during the last four weeks before birth and has the potential to reduce lung liquid volume.

Body Fluids↗
PubMed2001

Reliability of prenatal sonographic lung biometry in the diagnosis of pulmonary hypoplasia.

OBJECTIVE: The purpose of the present study was to assess the value of biometric lung measurements for the diagnosis of severe fetal pulmonary hypoplasia by investigating whether a significant correlation between two-dimensional lung biometry measurements and autopsy findings could be established. METHODS: This was a prospective study carried out between 1995 and 1997. Nomograms for normal fetuses of the anterior-posterior and transverse inner thoracic diameters, which describe the growth and shape of the lung, were used as a basis for diagnosis of pulmonary hypoplasia in fetuses at high risk of developing the condition (the fetuses had bilateral renal agenesis or multicystic kidneys; chronic PROM <25 gestational weeks or hydrothorax). Pregnancy was terminated by abortion or intrauterine death in 29/43 high-risk fetuses and autopsies were performed. Only the 29 fetuses for which there were autopsy findings were included in the study. RESULTS: The best plane for diagnosing pulmonary hypoplasia was the four-chamber view. The diagnostic accuracy for this view as expressed by the sensitivity was 57% for the anterior-posterior diameter and 44% for the transverse diameter; as expressed by the specificity it was 42% for the anterior-posterior diameter and 50% for the transverse diameter. The results for the four-chamber view for the various high-risk conditions were as follows: for fetuses with chronic PROM we obtained sensitivities of 75% and 50% (anterior-posterior and transverse dimensions, respectively) and specificities of 80% and 60% (anterior-posterior and transverse dimensions, respectively). The sensitivities of lung biometry in fetuses with hydrothorax were 1% and 80% for the two diameters, but there was a low specificity. In fetuses with bilateral renal agenesis or multicystic kidneys we obtained sensitivities of 36% and 30% (anterior-posterior and transverse dimensions, respectively) and a specificity of 50% (anterior-posterior dimension). CONCLUSIONS: The present results show that two-dimensional lung biometry is not a suitable method for antenatal detection of pulmonary hypoplasia. However, in individual cases with high risk for pulmonary hypoplasia, lung biometry might prove to be an additional diagnostic parameter.

Autopsy↗
PubMed2001

Increased nuchal translucency as a prenatal manifestation of congenital adrenal hyperplasia.

We present two cases of pregnant women with a previous history of congenital adrenal hyperplasia. In both cases the only abnormal feature in the initial pregnancy had been increased nuchal translucency at 10-14 weeks of gestation. The fetal karyotype was normal and a diagnosis of congenital adrenal hyperplasia was made after delivery. In their current pregnancies, both fetuses also had increased nuchal translucency and normal fetal karyotype. Diagnosis of 21-hydroxylase deficiency was made prenatally by DNA analysis. These findings in four affected fetuses suggest that congenital adrenal hyperplasia should be added to the list of genetic anomalies associated with an increase in nuchal translucency.

Adrenal Hyperplasia, Congenital↗
PubMed2001

Conversion of umbilical arterial Doppler waveforms to cardiac cycle triggering signals: a preparatory study for online motion-gated three-dimensional fetal echocardiography.

To remove motion artefacts, a device was built to convert "noisy" umbilical arterial Doppler waveforms (UADWs) from an ultrasound (US) system into sharp ECG R-wave-like cardiac cycle triggering signals (CCTSs). These CCTSs were then used to gate a simultaneous (online) 3-D acquisition of sectional fetal echocardiograms from another US system. To test the conversion performance, a study was carried out in sheep fetal twins. Pulmonary arterial flow waveforms (PAFWs) from implanted probes were traced, in the meantime, to determine the reference cardiac cycle. Interference caused by running the two nonsynchronised US systems was controlled to three degrees (not-noticeable, moderate, and severe), together with high (> or = 40 cm/s) and low (< 40) flow velocities on UADWs. The conversion efficiency, assessed by the percentage of UADWs converted into CCTSs, was in the range of 83% to 100% for not-noticeable and moderate interference, and 0% to 71% for severe interference. The triggering accuracy, assessed by [(time lag mean between the onsets of PAFWs and corresponding CCTSs) -- (its 99% confidence level)] / the mean, was 90% to 96% for the not-noticeable interference high- and low-flow groups and for the moderate interference high-flow group; 19% to 93% for the moderate interference low-flow group; and from not obtainable up to 90% for the severe interference groups. The results show that UADWs can be used as a satisfactory online motion-gating source even in the presence of moderate interference. The major problems are from severe interference or moderate interference with low-flow velocity, which can be minimised/eliminated by the integration of the individual systems involved.

Animals↗
PubMed2001

Application of three-dimensional power Doppler ultrasound in prenatal diagnosis.

OBJECTIVE: To assess the fetal cardiovascular system using three-dimensional power Doppler ultrasound (3D-PDU) in normal and abnormal conditions during the second half of gestation. SUBJECTS: Forty-five normal fetuses and 87 selected pregnancies with different abnormalities involving the vascular system were examined. METHODS: The following regions of interest were assessed: placental, umbilical, abdominal, renal, pulmonary and intracranial vessels together with the heart and great arteries. Equipment used was a commercially available HDI-3000 and 5000 ultrasound system with integrated 3D-Color Power Angio software. Data acquisition was performed by the free-hand technique. Images were reconstructed online. In pathological cases, a maximum of three attempts of 3D reconstruction was allowed to obtain the information needed. RESULTS: Satisfactory visualization of the fetal vascular system using 3D-PDU could be achieved in normal pregnancies. The main difficulty during the learning curve was the optimization of the power Doppler image prior to 3D data acquisition. Despite good visualization conditions, the reconstruction of satisfactory images was only possible in 56 out of the 87 (64%) pregnancies with abnormal vascular anatomy. These were abnormalities of placenta and umbilical vessels (n = 26), intra-abdominal and intrathoracic anomalies (n = 12), renal malformations (n = 9), central nervous system (n = 4) and cardiac defects (n = 5). The main reasons for the lack of information were fetal position and movements, overlapping with signals from neighboring vessels as well as technical limitations of the online system. Details and figures of the potential field of interest in prenatal diagnosis are presented.

Cardiovascular System↗
PubMed2001

Prenatal diagnosis of an ectopic intrathoracic kidney in right-sided congenital diaphragmatic hernia using color Doppler ultrasonography.

The prenatal sonographic features of a fetus with right-sided congenital diaphragmatic hernia diagnosed at 33 weeks are presented. Color Doppler demonstrated an abnormal course of the right renal artery, arising from the aorta and feeding the intrathoracic right kidney. This case report stresses the role of color Doppler in defining which organs have herniated in fetuses with diaphragmatic hernia.

Adult↗