Biomedical subjects

L D Platt

Publications and source records attributed to L D Platt.

At least 91 records · Page 5Linked to original sources

PubMed1991

Fetal choroid plexus cysts in the second trimester of pregnancy: a cause for concern.

Controversy surrounds the issue of recommending cytogenetic studies in second-trimester fetuses with fetal choroid plexus cysts. To assist in clarifying this issue, a prospective study was designed to describe the association between fetal choroid plexus cysts and aneuploidy in a large population. During a 3-year period 7350 women at 15 to 22 weeks' gestation underwent an ultrasonographic evaluation. Fetal choroid plexus cysts were diagnosed in 71 (0.96%) of these pregnancies. Sixty-two of the 71 patients elected to undergo amniocentesis. An abnormal karyotype was identified in four (6.4%) of these fetuses. One fetus had trisomy 21, and three fetuses were diagnosed with trisomy 18. These data indicate that it is reasonable to offer genetic counseling and cytogenetic studies in those patients identified as having a fetal choroid plexus cyst.

Aneuploidy↗

PubMed1991

MR imaging of fetal anomalies.

MR imaging can be used to confirm the presence of most gross fetal anomalies detected by sonography in the second and third trimesters. The MR imaging findings in 25 cases of fetal anomalies first identified on sonography are illustrated.

Congenital Abnormalities↗

PubMed1991

Fetal growth and development.

The advent and advancement of ultrasound technology have proved to be invaluable tools in the assessment of the fetus while still in the intrauterine environment. Ultrasound has given and continues to give us fresh insights into many aspects of the developing human. The area of fetal growth and development is a difficult one. Our lack of knowledge of the basic controlling influences has inhibited investigations in this area, but ultrasound has at least allowed us to begin to scratch the surface of this complex subject. We can now obtain very useful clinical information that usually has excellent correlation with gestational age, fetal size, fetal structure, and fetal function. We are just now beginning to document the natural history of many fetal abnormalities. Undoubtedly, advances in our knowledge of genetics and molecular biology and continuing technologic advances in imaging techniques will provide fresh insights and allow us to continue to probe and unlock the mysteries of fetal growth and development.

Biometry↗

PubMed1991

Use of femur length measured by ultrasonography to predict fetal maturity.

The ultrasonographic criteria of biparietal diameter greater than or equal to 9.2 cm and a grade III placenta have been shown to correlate with fetal maturity in the fetus of a nondiabetic mother in our population. These two criteria have helped reduce the incidence of third-trimester amniocenteses by 66.6% at our institution. Occasionally, however, because of fetal position, we are unable to obtain an accurate biparietal diameter. We therefore carried out a prospective study of 120 patients to evaluate the relationship between femur length of greater than or equal to 7.3 cm and fetal maturity. In this study, the addition of the femur length criterion increased the specificity of the ultrasonographic criteria for fetal maturity from 66.6% to 85%. The data suggest that femur length could be used along with the biparietal diameter and placental grade as an alternative to amniocentesis in term nondiabetic pregnancies.

Female↗

PubMed1990

Ultrasonographic diagnosis of a fetal abdominal mass: a case of a mesenchymal liver hamartoma and a review of the literature.

A case of a prenatally recognized hepatic mesenchymal hamartoma is presented and the literature reviewed. These tumors are benign and usually present in early infancy with symptoms that are related to the mass effect on adjacent organs. Radiologic methods used in the past to image this tumor include angiography and ultrasound. However, there is no specific radiologic finding, and, therefore, the diagnosis is usually made during surgery. Once the tumor is removed, the prognosis is generally good. With the increasing use of high resolution ultrasound in prenatal diagnosis, this rare tumor should be considered in the differential diagnosis of any multicystic mass found in the fetal abdomen. The recognition of a mass should then alert the physician to the need for early neonatal intervention.

Adult↗

PubMed1990

Prognostic indicators of the resolution of nonimmune hydrops fetalis and survival of the fetus.

To delineate any possible prognostic indicators, we reviewed the ultrasonographic and nonmorphometric findings in 19 antenatally diagnosed cases of nonimmune hydrops fetalis in which it was chosen to continue the pregnancy. Thirteen fetuses died and six survived. Of all parameters examined, including associated anomalies, abnormal karyotype, location of serous fluid, anemia, and possible cause of nonimmune hydrops fetalis, the most sensitive prognostic indicator was the real-time-directed M-mode echocardiographic measurement of the biventricular outer dimension in diastole. All fetuses with biventricular outer dimensions greater than 95% died, whereas all but one with normal biventricular outer dimensions had resolution of nonimmune hydrops fetalis and survived. This was highly significant (p less than 0.001) with the predictive value of a normal biventricular outer dimension being 86% and the predictive value of an enlarged biventricular outer dimension being 100%.

Chromosome Aberrations↗

PubMed1990

Ultrasonographic estimation of fetal weight in the clinically macrosomic fetus.

The purpose of this study is to evaluate models for the prediction of birth weight in fetuses suspected of being macrosomic. A total of 141 patients with standard measurements of the head, abdomen, and femur were studied. Linear regressions were performed with single parameters, squares, and all possible cross products in the generation of models with log (birth weight) and birth weight as dependent variables. These models were then compared with a group of previously published equations. Clinically, all models performed poorly. However, two models were significantly less accurate in the prediction of birth weight (p less than or equal to 0.05). The best results were obtained by equations that used abdominal circumference and femur length measurements. There was no improvement in models that contained log (birth weight) or birth weight as dependent variables or models with complex variables such as squares or cross products of measured parameters. In conclusion, when evaluating patients at risk of macrosomia, the best estimates of fetal weight can be obtained by models that contain abdominal circumference and femur length.

Body Weight↗

PubMed1990

The correlation of arterial lesions with umbilical artery Doppler velocimetry in the placentas of small-for-dates pregnancies.

The placentas of 14 growth-retarded fetuses with abnormal umbilical artery velocimetry and 15 appropriately grown fetuses with normal waveforms were collected immediately after delivery and analyzed in a blinded fashion. A large percentage of the arterial vessels in the placentas from the former group showed abnormal changes in the vessel wall. The percentage of abnormal arterial vessels in all placentas correlated significantly with the resistance index. This study provides an anatomical basis for the elevated resistance to blood flow in placentas from growth-retarded fetuses.

Adult↗

PubMed1990

Quantifiable polyhydramnios: diagnosis and management.

Little has been written regarding the ultrasonographic quantification of polyhydramnios or its subsequent management. Therefore, we designed this study to define polyhydramnios using the amniotic fluid index of greater than 2 SDs above the mean for late second- to third-trimester pregnancies, or 24 cm or greater. One hundred twelve nondiabetic women referred to Women's Hospital, Los Angeles County/University of Southern California Medical Center with the descriptive diagnosis of polyhydramnios made by experienced ultrasonographers were included in the study. There was poor correlation between these descriptions and fetal outcome. Twenty-six were qualitatively described as having severe, 29 as moderate, and 57 as mild polyhydramnios. Forty-nine of the 112 patients met our definition of significant polyhydramnios by having an amniotic fluid index of 24 cm or more. This particular definition allowed the inclusion of all fetuses with serious structural defects and/or death. Seven patients had an amniotic fluid index less than 24 cm, but with the traditional quantitative definition of one pocket of 8 cm or more; none of these patients had poor fetal outcome. These data appear to suggest that the use of descriptive definitions of polyhydramnios or a single fluid pocket of 8 cm or greater should be discarded in favor of using an amniotic fluid index of 24 cm or more. Once the diagnosis of polyhydramnios is made, the patient should have a detailed sonographic evaluation, be offered cytogenetic studies, and have antepartum surveillance.

Congenital Abnormalities↗

PubMed1990

Ultrasound imaging of the cranium and spine.

A general description and discussion of the normal head and spine, and major fetal anomalies has been presented. It is important to remember that there can be wide variability in the structural findings noted in the fetus with ventricular dilatation or abnormal cerebellar development. If an abnormality of the fetal head and spine is seen, it is important to carefully assess other areas of fetal anatomy because of the increased likelihood of coexisting anomalies. Because of the increased incidence of chromosomal abnormalities, evaluation by percutaneous umbilical blood sampling, amniocentesis or placental biopsy is recommended for all structural abnormalities of the fetal head and spine. The best clinical approach for the ultrasonologist is to accurately describe and quantify the abnormalities for geneticist, pediatrician and or neurosurgeon to discuss the prognosis. Accurate evaluation of the type, location and extent of a neural tube defect is important to enable the family to understand possible outcomes of the pregnancy.

Female↗

PubMed1990

Fetal abdominal abnormalities associated with genetic syndromes.

Sonographic technology has given the prenatal diagnostician the ability to accurately visualize fetal malformations. This article demonstrates the currently available capability of applying sonographically derived information concerning fetal dysmorphology to our knowledge of genetic disorders and syndromes. As a result, there can be a significant improvement in the management and counseling of these patients. After an initial discussion of normal embryology, principles of abdominal ultrasonography are discussed and applied to the following anomalies: omphalocele, gastroschisis, diaphragmatic hernia, duodenal atresia, other intestinal atresias and stenoses, renal anomalies, and obstructive uropathies.

Abdomen↗

PubMed1990

Performing cytogenetic studies on ascitic, amniotic and hygroma fluid.

The importance of obtaining cytogenetic studies on antenatally diagnosed structural malformations is well recognized. In two cases, three fetal compartments were sampled, each resulting in successful cytogenetic studies. Fluid was obtained under ultrasound guidance from amniotic fluid, fetal ascites and cystic hygroma fluid. Fluid from the hygroma itself may be the easiest compartment to analyze.

Amniocentesis↗

PubMed1989

Antepartum improvement of abnormal umbilical artery velocimetry: does it occur?

Absence of end-diastolic velocity on umbilical artery velocimetry suggests extreme elevation of placental vascular resistance and is associated with adverse pregnancy outcome. This study was undertaken to assess whether antepartum improvement of abnormal umbilical artery waveforms occurs. Thirty-one fetuses identified with absence of end-diastolic velocity between July 1985 and December 1987 at Women's Hospital underwent sequential umbilical artery velocimetry at 1- to 3-day intervals. The presence of end-diastolic velocity on subsequent scans was considered an improvement in waveforms. The mean diagnosis-to-delivery interval (20.5 +/- 4 days), gestational age at delivery (32.5 +/- 1.2 weeks), and birth weight (1440 +/- 210 gm) were significantly higher in five fetuses that showed improvement in waveforms, compared with the 26 fetuses that did not show improvement in waveforms (9.5 +/- 3.5 days, 29.5 +/- 0.9 weeks, and 940 +/- 70 gm, respectively). Ten perinatal deaths occurred, for a perinatal mortality rate of 32.3%. There was significant perinatal morbidity in the overall group as judged by intrauterine growth retardation, meconium, 5-minute Apgar scores less than 7, and cesarean section for fetal distress. We conclude that although absence of end-diastolic velocity is associated with adverse pregnancy outcome, antepartum improvement in umbilical artery waveforms occurred in 15% of the fetuses studied and was associated with an improvement in perinatal outcome. Factors that influenced this improvement, though unclear, might be related to maternal bed rest or medication and require further investigation.

Apgar Score↗

PubMed1989

Relationship of systolic/diastolic ratios from umbilical velocimetry to fetal heart rate.

We assessed the relationship between systolic/diastolic ratios as determined by umbilical velocimetry to fetal heart rate. Umbilical velocimetry was performed with continuous-wave Doppler ultrasound and systolic/diastolic ratios and fetal heart rate for the corresponding cardiac cycles were calculated in four groups of patients. Group 1 consisted of 30 patients undergoing antepartum fetal testing; systolic/diastolic ratios were found to be significantly lower (mean +/- SD, 2.0 +/- 0.15) during an evoked fetal heart rate acceleration with an artificial larynx than either before (2.4 +/- 0.14) or after the acceleration (2.35 +/- 0.10, p less than 0.01). In 20 patients with pyelonephritis (group 2), systolic/diastolic ratios were significantly lower during initial fetal tachycardia (1.6 +/- 0.21) as compared with those obtained after its resolution (2.1 +/- 0.12, p less than 0.08). In the 25 patients with chorioamnionitis in group 3, systolic/diastolic ratios were significantly higher during initial fetal tachycardia (1.4 +/- 0.21) than after its resolution (1.9 +/- 0.15, p less than 0.05). Twenty patients in labor (group 4) had 10 serial measurements at 1 to 2-hour intervals of systolic/diastolic ratio and FHR. Least-squares regression of each patient showed a negative slope that differed statistically from zero (p less than 0.05). There were no patients with elevated systolic/diastolic ratios greater than 3.0 in any group and all patients delivered fetuses appropriate for gestational age. These findings suggest an inverse relationship between systolic/diastolic ratio and fetal heart rate. Additionally, an alteration in fetal heart rate within the range studied does not itself produce abnormal ratios. Therefore normalization of the systolic/diastolic ratio for heart rate may be considered in clinical studies for statistical analysis and comparison but may have little practical or clinical relevance when the ratios are abnormal.

Blood Flow Velocity↗

PubMed1989

A comparative study of fetal umbilical velocimetry with continuous- and pulsed-wave Doppler ultrasonography in high-risk pregnancies: relationship to outcome.

Systolic/diastolic ratios of umbilical velocimetry obtained with either continuous-wave or pulsed-wave Doppler ultrasonography have been used to assess downstream placental vascular resistance and fetal well-being. The purpose of this study is to compare the efficacy of systolic/diastolic ratios obtained by continuous-wave and pulsed-wave Doppler ultrasonography in the prediction of poor pregnancy outcome. Continuous-wave and pulsed-wave umbilical velocimetry was performed and systolic/diastolic ratios were measured in 200 high-risk pregnancies in the third trimester by use of Angioscan III and a General Electric RT 3600 scanner, respectively. A total of 165 study participants had normal systolic/diastolic ratios and 35 participants had elevated ratios (greater than 3.0) with both continuous-wave and pulsed-wave Doppler ultrasonography. Both methods identified 35 participants with abnormal ratios, and none of the women was misclassified by either method. The pulsed-wave and continuous-wave values for 35 participants with elevated ratios were 6.35 +/- 1.52 and 6.23 +/- 1.58, respectively; values for 165 participants with normal ratios were 1.95 +/- 0.40 and 1.96 +/- 0.41, respectively (not significantly different). Participants with elevated systolic/diastolic ratios within 7 days of delivery had significantly higher incidence of adverse pregnancy outcome as judged by small-for-gestational-age fetuses, presence of meconium at delivery, fetal distress in labor, cesarean sections and 5-minute Apgar scores less than 7. Fetuses with elevated ratios were delivered at an earlier gestational age (34 +/- 1.2 weeks), had lower birth weights (1422 +/- 151 gm), and spent more time in the neonatal intensive care unit (17.1 +/- 5.2 days), compared with fetuses with normal ratios (delivered at 38.5 weeks +/- 0.9 weeks, 3100 +/- 210 gm birth weights, and 2 +/- 0.2 days spent in neonatal intensive care units, respectively, p less than 0.05). We therefore conclude that continuous-wave and pulsed-wave Doppler ultrasonography produce similar results with regard to systolic/diastolic ratios in high-risk pregnancies, and either method appears to be a valuable adjunct in the surveillance of high-risk pregnancies.

Apgar Score↗

PubMed1989

Continuous tissue pH monitoring in the term fetus.

Since Saling's work in 1961, many investigators have attempted to perfect methods to detect fetal acidosis during labor. A system for continuous tissue pH monitoring of the fetus is evaluated in this study of 59 patients. There was poor correlation of tissue pH values and capillary scalp pH values in 19 cases (r = 0.487), and no significant correlation of tissue pH values to the outcome measurements of Apgar scores and cord gas levels. The benefits realized were those of monitoring the trend of tissue pH over time. We believe that a continuous pH monitoring system offers several advantages over intermittent fetal scalp sampling. Further refinement of the technology employed may offer such a system in the future.

Acidosis↗

PubMed1989

Intrapartum Doppler velocimetry, amniotic fluid volume, and fetal heart rate as predictors of subsequent fetal distress. I. An initial report.

This study examines the usefulness of umbilical artery Doppler velocimetry, amniotic fluid volume assessment, and fetal heart rate data in the early intrapartum period as predictors of subsequent fetal distress. A total of 109 patients seen in the latent phase of labor in the labor and delivery area were studied. Both an abnormal initial fetal heart rate and an amniotic fluid index less than or equal to 5.0 cm were associated with a significant increase in the incidence of intrapartum fetal distress. Conversely, a systolic/diastolic ratio greater than 3.0 by Doppler ultrasonography was not associated with increased fetal morbidity. Overall, the sensitivities, specificities, and positive predictive values of the fetal heart rate tracing and the amniotic fluid volume assessment were comparable. Doppler systolic/diastolic ratios showed very poor sensitivity and positive predictive value. We conclude that the fetal heart rate tracing or the assessment of amniotic fluid volume in the early intrapartum period are reasonable predictors of subsequent fetal condition. The lack of patients with the absence of or reverse umbilical velocity preclude conclusions with regard to Doppler systolic/diastolic ratios for this purpose.

Adolescent↗

PubMed1989

Maternal and fetal blood flow velocity waveforms in patients with preterm labor: relationship to outcome.

Elevated systolic/diastolic ratios obtained by umbilical and uterine velocimetry have been used to predict adverse pregnancy outcome. We performed pretherapy umbilical and uterine velocimetry by means of continuous-wave Doppler ultrasonography on 92 patients who came for treatment in preterm labor. Fourteen (15.2%) and 12 (13%) patients had elevated uterine (greater than 2.6) and umbilical (greater than 3.5) systolic/diastolic ratios, respectively, and 9 (9.8%) patients had both ratios elevated. Overall 17 (18.5%) patients had at least one abnormal systolic/diastolic ratio. Patients with abnormal Doppler waveforms had a significantly shorter gestation, infants with lower birth weights, and a higher incidence of adverse pregnancy outcome as determined by meconium, cesarean section for fetal distress, low 1- and 5-minute Apgar scores, and days in the neonatal intensive care unit, compared with patients with normal systolic/diastolic ratios. There was no significant difference in the ability of uterine, umbilical, or combined velocimetry to predict preterm birth or adverse pregnancy outcome. Doppler studies in preterm labor patients may help to identify patients at increased risk for preterm birth and poor pregnancy outcome. Further studies are warranted to assess its usefulness in the evaluation of these patients.

Adolescent↗