bluuebunny/crossref_metadata_2025_split huggingface dataset:
Customizing fetal biometric charts
Authors: Pang M. W. , Leung T. N. , Sahota D. S. , Lau T. K. , Chang A. M. Z. 
Published: August 2003

AbstractObjectiveTo study the effects of maternal and pregnancy characteristics on fetal biometric size using longitudinal ultrasound measurements and to construct customized models for fetal biometric size charts.MethodsA cohort of 533 healthy pregnant women with normal singleton pregnancies were recruited for regular ultrasound examination for fetal biometry between 24 and 40 weeks' gestation. Multilevel modeling was used to construct models of fetal head size, femur length and abdominal circumference. Variables of maternal and pregnancy characteristics including booking weight and height, age, parity and fetal sex were included in the construction of the customized fetal biometric size charts.ResultsIncreased fetal head size and abdominal circumference were significantly associated with extremes of maternal age. Maternal height had a statistically significant influence on biparietal diameter. Maternal booking weight had an influence on fetal abdominal circumference and femur length. Fetal sex was found to have a statistically significant influence on the final regression models of biparietal diameter, head circumference and femur length. Parity had an influence on fetal head circumference and abdominal circumference.ConclusionsMaternal and pregnancy characteristics have a significant influence on in‐utero fetal biometry. We produced models to construct customized fetal biometric size charts. Further validation studies are necessary to evaluate the clinical usefulness of such customized fetal biometric size charts. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Accuracy of cervical transvaginal sonography in predicting preterm birth: a systematic review
Authors: Honest H. , Bachmann L. M. , Coomarasamy A. , Gupta J. K. , Kleijnen J. , Khan K. S. 
Published: August 2003

AbstractThis review investigates the accuracy with which transvaginal cervical sonography predicts spontaneous preterm birth. Published studies were identified without language restrictions through nine different databases and manual searching of bibliographies of known primary and review articles. Studies were selected if they undertook antenatal transvaginal sonographic cervical assessment among a population of pregnant women with known gestational age of delivery. There were 46 primary articles, which included a total of 31 577 women, consisting of 33 studies in asymptomatic and 13 studies in symptomatic women. Data were extracted for the studies' characteristics and quality. Accuracy data were used to form 2 × 2 contingency tables for various cervical length measurements with birth before 32, 34 and 37 weeks' gestation as the reference standards. Data were stratified according to singleton or twin pregnancy, gestational age at testing, cervical length threshold, and the various reference standards, and were pooled to produce summary estimates of likelihood ratios (LRs). Our review showed that transvaginal cervical sonography identifies women who are at higher risk of spontaneous preterm birth, although there was a wide variation amongst studies with respect to gestational age at testing, definition of threshold of abnormality and definition of reference standard. The most commonly reported sub‐group was testing of asymptomatic women at < 20 weeks' gestation using a threshold cervical length of 25 mm with spontaneous preterm birth before 34 weeks' gestation as the reference standard. The summary LR+ for this group was 6.29 (95% CI, 3.29–12.02), with corresponding LR− of 0.79 (95% CI, 0.65–0.95). Both cervical length measurement and funneling, whether alone or in combination, appear to be useful (depending on the threshold chosen to define the abnormality) in predicting spontaneous preterm birth in asymptomatic women. For symptomatic women there was a paucity of data, although the degree of funneling appeared to be predictive of spontaneous preterm birth. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Effect of fetal gender on first‐trimester ductus venosus blood flow
Authors: Prefumo F. , Venturini P. L. , De biasio P. 
Published: August 2003

AbstractObjectivesRecent reports have suggested that nuchal translucency (NT) measurements in the first trimester may be influenced by fetal gender. Since both NT and central venous blood flow are considered to be related to fetal cardiac function, we investigated gender‐related differences in first‐trimester ductus venosus Doppler indices.MethodsA total of 73 male and 79 female normal fetuses at 10–14 weeks of gestation were included in the study. The pulsatility index for veins (PIV), peak velocity during ventricular systole (S‐wave), time‐averaged maximum velocity (TAMV) and A‐wave velocity (A‐wave) were recorded in each case and converted to the corresponding Z‐scores.ResultsThe mean Z‐score values of PIV, S‐wave and TAMV were significantly lower in male fetuses compared to female fetuses (P < 0.01 for all three indices). By contrast, A‐wave velocities were not different in the two groups. The correlation between S‐wave velocity and TAMV was significant in both male (P < 0.001) and female (P < 0.001) fetuses, while PIV did not appear to be related to TAMV either in males (P = 0.90) or in females (P = 0.49). A‐wave velocity had a significant negative correlation with PIV in both groups. Finally, PIV was significantly correlated with S‐wave velocity in female fetuses (P < 0.01) but not in males (P = 0.14).ConclusionThese findings suggest that early cardiovascular development may be different in male and female fetuses. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
A new successful therapy for fetal chylothorax by intrapleural injection of maternal blood
Authors: Parra J. , Amenedo M. , Muñiz‐Díaz E. , Ormo F. , Simó M. , Vega C. , FernÁndez J. G. , Senosiain R. , Moliner E. , Guinovart G. 
Published: August 2003

AbstractWe present two cases of fetal chylothorax and hydrops diagnosed at 20 weeks' gestation, both of which underwent successful intrauterine treatment. In Case 1, a transient, near total resolution began 2 weeks after an iatrogenic hemothorax following a second thoracocentesis performed at 24 + 6 weeks. Because of pleural fluid reaccumulation, a Cesarean section was performed at 36 weeks. The 3805‐g female neonate was admitted to neonatal intensive care but was discharged 50 days later in a healthy condition. In Case 2, resolution occurred after a third thoracocentesis and a second pleural injection of maternal blood, performed at 26 weeks. A 2660‐g female neonate was delivered vaginally at 38 weeks. The infant remained asymptomatic and was discharged aged 4 days. Our experience suggests a possible useful role of intrapleural blood injection for the treatment of fetal chylothorax. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Ductus venosus blood flow velocity characteristics of fetuses with single umbilical artery
Authors: Raio L. , Ghezzi F. , Di Naro E. , Cromi A. , Buttarelli M. , Sonnenschein M. , Dürig P. 
Published: August 2003

AbstractObjectivesSonographic Doppler evaluation of the fetal ductus venosus has been proved to be useful in the evaluation of fetal cardiac function. The aim of this study was to investigate the ductus venosus blood flow profile in fetuses with single umbilical artery and to correlate it with the umbilical cord morphology.MethodsFetuses at >20 weeks' gestation with single umbilical artery who were otherwise healthy were consecutively enrolled into the study. The sonographic examination included evaluation of the following Doppler parameters: umbilical artery resistance index, maximum blood flow velocity of the ductus venosus during ventricular systole (S‐peak) and atrial contraction (A‐wave), ductus venosus time‐averaged maximum velocity (TAMXV), and pulsatility index for veins (PIV). The cross‐sectional area of the umbilical cord and its vessels were measured in all cases. The Doppler and morphometric values obtained were plotted on reference ranges.ResultsA total of 88 fetuses with single umbilical artery were scanned during the study period. Of these 52 met the inclusion criteria. The S‐peak velocity, A‐wave velocity, and TAMXV were below the 5th centile for gestational age in 57.7%, 59.6%, and 57.7% of cases, respectively. The PIV was within the normal range in 80.1% of cases. The umbilical vein cross‐sectional area of fetuses with single umbilical artery was above the 95th centile for gestational age in 34.6% cases.ConclusionsThe ductus venosus blood flow pattern is different in fetuses with single umbilical artery from that in those with a three‐vessel cord. This difference may be caused in part by the particular morphology of umbilical cords with a single artery. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Frequency and type of adnexal lesions in autopsy material from postmenopausal women: ultrasound study with histological correlation
Authors: Valentin L. , Skoog L. , Epstein E. 
Published: August 2003

AbstractObjectiveTo determine the prevalence and histology of adnexal cysts in autopsy material from postmenopausal women.MethodsThe study included 104 adnexa from 52 consecutive women with a mean age of 79 (range, 64–96) years, who underwent autopsy and died from causes other than gynecological cancer or intraperitoneal cancer of extragenital origin. The adnexa were removed, put in sterile saline in separate plastic containers and examined sonographically using an 8‐MHz transvaginal transducer. Each lesion detected at ultrasound examination was measured with calipers on the frozen ultrasound image and was classified according to its ultrasound morphology. The adnexa were then put in 4% formaldehyde solution and sent for histological examination.ResultsAt ultrasound examination, 56% (29/52) of the women had adnexal lesions, cysts being detected in 54% (28/52) and solid lesions in 12% (6/52). At least one adnexal cyst with a largest diameter of 2–10 mm, > 10 mm, > 20 mm, > 30 mm and > 40 mm, respectively, was found in 33% (17/52), 21% (11/52), 12% (6/52), 8% (4/52) and 4% (2/52) of the women. The largest lesion measured 65 mm in diameter. At ultrasound examination we found 36 intra‐ovarian cysts (26 inclusion cysts, three cystically degenerated corpora albicantia, five simple cysts, one serous cystadenoma and one 3‐mm cyst not confirmed by the pathologist), 19 extra‐ovarian cysts (all simple cysts according to the pathologist), five solid intra‐ovarian lesions (two fibromas, one cystadenofibroma, one Brenner tumor and one case of dystrophic calcification), and one solid extra‐ovarian lesion (fibroma). In addition, the pathologist detected one 20‐mm solid corpus albicans, eight extra‐ovarian simple cysts of 1–8 mm, and 77 intra‐ovarian inclusion cysts of 1–4 mm.ConclusionSmall (≤ 50 mm) benign adnexal cysts and small benign solid tumors are so common in postmenopausal women that their presence may be regarded as normal. Our results support conservative management of adnexal lesions with benign ultrasound morphology incidentally detected at ultrasound examination in postmenopausal women. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Partial and total anomalous pulmonary venous connection in the fetus: two‐dimensional and Doppler echocardiographic findings
Authors: Valsangiacomo E. R. , Hornberger L. K. , Barrea C. , Smallhorn J. F. , Yoo S.‐J. 
Published: August 2003

AbstractObjectivePrenatal diagnosis of total (TAPVC) or partial (PAPVC) anomalous pulmonary venous connection in isolation or associated with other cardiac disease is important for appropriate prenatal counseling and perinatal management. We sought to assess the echocardiographic clues to the fetal diagnosis of TAPVC and PAPVC in a cohort of affected fetuses.MethodsWe retrospectively reviewed 29 fetal echocardiograms performed in 16 pregnancies with fetal TAPVC or PAPVC, systematically analyzing heart chamber size, presence of a confluence behind the left atrium or of a vertical vein, and Doppler flow patterns.ResultsPrenatal diagnosis was made at a mean gestational age of 27 ± 7 weeks. TAPVC was found in 11 cases; five cases for each of supracardiac and infracardiac types and one mixed type. PAPVC was diagnosed in five fetuses, four of which had scimitar syndrome. Ten fetuses had an additional major cardiac defect, including hypoplastic left heart syndrome and right atrial isomerism. In three cases the prenatal diagnosis was only made at follow‐up assessment. Among TAPVC cases, visualization of a confluence behind the left atrium (10/11) and a vertical vein (11/11) were the most consistent echocardiographic clues. Dextrocardia and a small right pulmonary artery suggested scimitar syndrome. The diagnosis was confirmed postnatally or at autopsy in 12 cases. In six fetuses with TAPVC and obstruction confirmed postnatally, continuous turbulent flow in the vertical vein and monophasic continuous flow in the pulmonary veins were demonstrated by color and spectral Doppler.ConclusionsFetal echocardiography permits prenatal diagnosis of TAPVC or PAPVC. Spectral and color Doppler provide clues to the presence of an obstructed pulmonary venous pathway. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
The role of Doppler studies in predicting individual intrauterine fetal demise after laser therapy for twin–twin transfusion syndrome
Authors: Martínez J. M. , Bermúdez C. , Becerra C. , López J. , Morales W. J. , Quintero R. A. 
Published: August 2003

AbstractObjectiveTo investigate the role of Doppler studies in predicting individual fetal demise in patients scheduled for selective laser photocoagulation of communicating vessels (SLPCV) for twin–twin transfusion syndrome (TTTS).MethodsDoppler studies of the umbilical artery, umbilical vein, ductus venosus, tricuspid valve regurgitation and middle cerebral artery were performed in the donor and recipient twins before and 24 hours after SLPCV. Results were analyzed cross‐sectionally and longitudinally. As multiple comparisons were made, an a priori alpha rejection was set at P < 0.001.ResultsOne hundred and ten consecutive patients were available for analysis. Overall fetal survival was 68.6% (151/220) with at least one survivor in 88.2% (97/110) of cases. Absent or reversed end‐diastolic velocity in the umbilical artery of the donor twin was the only preoperative Doppler result predictive of intrauterine fetal demise (IUFD) (10/15, 66.7%, P < 0.001). Postoperatively, reversed flow during atrial contraction in the ductus venosus of the donor twin showed a trend towards prediction of IUFD of this fetus (4/5, 80%, P = 0.007). No other Doppler studies, including the longitudinal analyses, were predictive of IUFD.ConclusionsOur data suggest that preoperative absent or reversed end‐diastolic velocity in the umbilical artery may be useful in predicting individual fetal demise of the donor twin in TTTS patients scheduled for SLPCV. This may reflect the role of decreased individual placental mass that may be associated with some donor twins. The inability of other Doppler studies to predict individual IUFD may be explained preoperatively by the effect of the interfetal vascular connections on the individual Doppler signals and postoperatively by the effect of surgery or the timing of the assessment. Our findings may be important in patient counseling, in furthering understanding of the disease, and perhaps in improving surgical technique. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Prenatal diagnosis of portal vein thrombosis by ultrasound
Authors: Stiller R. J. , Neale D. , Schwartz D. , Laifer S. , Kleinman G. 
Published: August 2003

AbstractNeonatal portal vein thrombosis (PVT) is a rare condition seen in the setting of thrombophilia or after umbilical vein catheterization. We report a case of fetal PVT with abnormal antenatal ultrasound findings at 27 weeks of gestation. This presented initially as dilation of the intrahepatic umbilical vein. To our knowledge, this is the first reported case evaluated prenatally. Color Doppler ultrasound was valuable in detecting constriction of the vessel with a high‐velocity jet seen past the obstruction site. A discussion of this condition and differential diagnosis is presented. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Randomized controlled trial using low‐dose aspirin in the prevention of pre‐eclampsia in women with abnormal uterine artery Doppler at 23 weeks' gestation
Authors: Yu C. K. H. , Papageorghiou A. T. , Parra M. , Palma Dias R. , Nicolaides K. H. ,   The Fetal Medicine Foundation Second Trimester Screening Group
Published: August 2003

AbstractObjectivePre‐eclampsia, which is a major cause of perinatal and maternal morbidity and mortality, is thought to be due to impaired perfusion of the placenta. There is contradictory evidence that the administration of low‐dose aspirin may provide effective prophylaxis against the subsequent development of pre‐eclampsia. In this study we tested the hypothesis that in women identified as being at high‐risk for pre‐eclampsia, because of impaired flow in the uterine arteries, the prophylactic use of low‐dose aspirin from 23 weeks of gestation can reduce the incidence of pre‐eclampsia.MethodsWe used color and pulsed Doppler to measure the flow in the uterine arteries in 19 950 singleton pregnancies at 22–24 weeks of gestation. Those women exhibiting increased impedance were recruited into a randomized study of aspirin 150 mg per day or placebo. We compared the two groups for the incidence of pre‐eclampsia and the other consequences of impaired placentation.ResultsThe screening study identified 844 women (4.2%) as being at high risk of uteroplacental insufficiency. After exclusion and refusal, 560 women were randomly allocated to aspirin 150 mg or placebo per day until 36 weeks' gestation. There were no significant differences between the aspirin and placebo groups in either the incidence of pre‐eclampsia (18% vs. 19%, P = 0.6) or pre‐eclampsia requiring delivery below 34 weeks (6% vs. 8%, P = 0.36). Furthermore, the administration of aspirin did not significantly alter the incidence of preterm delivery (24% vs. 27%, P = 0.46), birth weight below the 5th centile (22% vs. 24%, P = 0.4), perinatal death (3% vs. 1%, P = 0.33) or placental abruption (4% vs. 2%, P = 0.12).ConclusionIn pregnancies with impaired placentation, as demonstrated by increased impedance to flow in the uterine arteries, the daily administration of 150 mg aspirin after 23 weeks of gestation does not prevent the subsequent development of pre‐eclampsia. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Prenatal diagnosis of cephalothoracopagus janiceps disymmetros using three‐dimensional power Doppler ultrasound and magnetic resonance imaging
Authors: Chen C.‐P. , Shih J.‐C. , Shih S.‐L. , Huang J.‐K. , Huang J.‐P. , Lin Y.‐H. , Wang W. 
Published: August 2003

AbstractWe report the prenatal imaging findings of a rare case of cephalothoracopagus janiceps disymmetros diagnosed at 28 weeks' gestation. Two‐dimensional ultrasound and magnetic resonance imaging demonstrated janiceps conjoined female twins with a single fused cranial vault, duplicated cerebra, two faces, four eyeballs, a fused thorax, two hearts, two thoracic spines, eight limbs and polyhydramnios. Three‐dimensional and power Doppler ultrasound established the definitive classification of cephalothoracopagus conjoined twins and displayed the shared circulation between the two separate hearts. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Universal lattice decoding: principle and recent advances
Authors: Mow Wai Ho 
Published: August 2003

AbstractThe idea of formulating the detection of a lattice‐type modulation, such as M‐PAM and M‐QAM, transmitted over a linear channel as the so‐called universal lattice decoding problem dates back to at least the early 1990s. The applications of such lattice decoders have proliferated in the last few years because of the growing importance of some linear channel models such as multiple‐antenna fading channels and multi‐user CDMA channels. The principle of universal lattice decoding can trace its roots back to the theory and algorithms developed for solving the shortest/closest lattice vector problem for integer programming and cryptoanalysis applications. In this semi‐tutorial paper, such a principle as well as some related recent advances will be reviewed and extended. It will be shown that the lattice basis reduction algorithm of Lenstra, Lenstra and Lovász (LLL) can significantly improve the performance of suboptimal lattice decoders such as the zero‐forcing and VBLAST detectors. In addition, new implementation of the optimal lattice decoder that is particularly efficient at moderate signal‐to‐noise ratios will also be presented. Copyright © 2003 John Wiley & Sons, Ltd.
Analysis and realization of a physical CDD system
Authors: Y. Lee William C. 
Published: August 2003

AbstractThe Code Division Duplexing (CDD) system has been developed recently. It is based on using a Code Division Multiple Access (CDMA) scheme on a Time Division Duplexing (TDD) system; the code applied to the CDD system is not the Walsh code, but rather an advanced smart code. In the past, the CDMA scheme can only be used in a Frequency Division Duplexing (FDD) system for cellular operations. But with this smart code applied to CDMA scheme, the CDMA scheme can be used in a TDD system for cellular operations. The smart code together with the TDD system becomes a CDD system. This CDD system can improve the current interference‐limited environment to a noise‐limited environment. In reality, the smart code cannot eliminate the interference entirely. This paper will analyze the anticipated physical CDD system performance based on the characteristics of the smart code. The cross‐correlation value between two codes in a smart code set does impact the overall error probability and the system capacity. The new calculation introduced in this paper can provide a better understanding of the performance of the CDD systems. Copyright © 2003 John Wiley & Sons, Ltd.
Code acquisition of ZCZ‐CDMA systems based on complete complementary codes
Authors: Guo Xiaoxu , Chen Jie , Suehiro Naoki 
Published: August 2003

AbstractIn recent years, a new quasi‐synchronous CDMA (QS‐CDMA) system based on complete complementary codes with zero correlation zones (ZCZ), named ZCZ‐CDMA system, has been proposed. In a ZCZ‐CDMA system, data transmission efficiency can be greatly improved by accurately detecting the multi‐path properties of the communication channel utilizing the unique correlation features of the ZCZ sequence. As for the despreading operation and the code acquisition, the ZCZ‐CDMA system however is more complicated and difficult than the conventional DS‐CDMA systems. In this paper, we discuss the issues of the code acquisition in ZCZ‐CDMA systems, and propose an efficient code acquisition scheme, called two‐stage search (TSS) scheme. In the first stage of the TSS code acquisition scheme, a predictive code phase is coarsely searched, and then a fine search utilizing the unique features of the ZCZ‐sequences is carried out in the second stage. Simulation results show that the proposed scheme achieves better performance in terms of search time and hardware complexity than conventional code acquisition schemes. Copyright © 2003 John Wiley & Sons, Ltd.
Williamson–Hadamard spreading sequences for DS‐CDMA applications
Authors: Seberry Jennifer , Wysocki Beata J. , Wysocki Tadeusz A. 
Published: August 2003

AbstractOrthogonal bipolar spreading sequences are used in direct sequence code division multiple access (DS‐CDMA) systems for both spectrum spreading and channel separation. The most commonly used sequences are Walsh–Hadamard sequences of lengths being an integer power of 2. A construction based on Williamson's arrays leading to sequences of lengths N≡4 (mod 8) is presented in the paper. Aperiodic correlation characteristics, for example sequence sets of lengths 12–252 are presented. The correlation properties of the sequence sets are later improved using a diagonal modification technique. Copyright © 2003 John Wiley & Sons, Ltd.