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Biomedical subjects

R L Deter

Publications and source records attributed to R L Deter.

At least 91 records · Page 5Linked to original sources
PubMed1984

Relation of fetal femur length to neonatal crown-heel length.

Sonographically measured femur lengths in 102 fetuses were compared with neonatal crown-heel lengths within 72 hours of delivery. The optimal model for describing crown-heel length as a function of femur length was a linear model, with a coefficient of determination (r2) of 66 per cent; the standard deviation in predicting crown-heel length from femur length was 2.4 cm. These data were compared with autopsy data from the literature, which showed an even stronger correlation between femur length and crown-heel length. Because of the strong correlation between these two dimensions, the femur length should prove useful in the detection of intrauterine growth retardation when crown-heel length is compromised. It should also be useful as a variable in the prediction of fetal weight in utero, since crown-heel lengths at the extremes of normal can significantly affect in utero weight estimates using ultrasound.

Body Height↗
PubMed1983

Computer assisted analysis of fetal age in the third trimester using multiple fetal growth parameters.

A new technique is described for predicting menstrual age in the third trimester of pregnancy (28-42 weeks) using multiple fetal growth parameters (biparietal diameter, head circumference, abdominal circumference, femur length). Evaluation of this technique in 177 normal third trimester pregnancies demonstrated that significant improvement in the variability in predicting menstrual age can be achieved when two or more parameters are used collectively instead of a single parameter used individually. The optimal combination prior to 36 weeks was biparietal diameter, abdominal circumference, and femur length, while after 36 weeks the optimal combination was head circumference, abdominal circumference, and femur length. The use of these combinations resulted in smaller mean errors, standard deviations, and maximum errors. Regression equations and tables of normal values are provided to facilitate the use of this dating method.

Diagnosis, Computer-Assisted↗
PubMed1983

Quantitative characterization of the growth of the fetal kidney.

The time-dependent changes in the antero-posterior (A-P) diamter and length (L) of fetal kidneys has been evaluated by means of statistical analysis of measurements made during the third trimester in a normal population. Two hundred eighty pregnant women were examined between 22 and 40 weeks of gestation. Differences between operator-scanner combinations were evaluated. The relationships of the A-P diameter and length to menstrual age were determined in cross-sectional and longitudinal studies of kidney growth. The results obtained confirmed that measurements of fetal kidney can be used as an additional parameter in the routine assessment of fetal well being and to rule out kidney malformations characterized by changes in kidney size.

Female↗
PubMed1983

A date-independent predictor of intrauterine growth retardation: femur length/abdominal circumference ratio.

The relation between sonographically measured fetal femur length and abdominal circumference (expressed as femur length/abdominal circumference X 100) was studied in 361 normal pregnancies between 15 and 42 weeks. This ratio was found to be independent of menstrual age, with a normal range after 21 weeks (mean +/- 2 SD) of 22 +/- 2. This ratio also was evaluated as a predictor of intrauterine growth retardation in 30 cases using the 90th percentile (23.5) as the upper limit of normal, which resulted in identification of 63% of the growth-retarded fetuses. Because it is independent of menstrual age, this ratio should prove most useful in evaluating high-risk patients who present in the third trimester of pregnancy with no dates. It is also of value in detecting growth retardation in patients with good menstrual history, since it was shown to become abnormal in asymmetrically growth-retarded fetuses before the estimated weight fell below the 10th percentile.

Abdomen↗
PubMed1983

A prospective evaluation of fetal femur length as a predictor of gestational age.

Variability (+/- 2 SD) in prediction of fetal gestational age from ultrasonographic measurements of fetal femur length was evaluated prospectively in 287 fetuses between 18 and 42 weeks' gestation. Variability increased throughout pregnancy, ranging from +/- 11.6 days between 18 and 24 weeks to +/- 22.7 days in the last six weeks of pregnancy. These findings are comparable with variability in prediction of gestational age from biparietal diameter measurement between 18 and 42 weeks, which indicates that the femur length may serve as an adequate alternative for prediction of gestational age in cases in which the biparietal diameter cannot, for technical reasons, be obtained.

Female↗
PubMed1982

Longitudinal studies of fetal growth with the use of dynamic image ultrasonography.

To characterize the growth of individual fetuses, serial measurements of the crown-rump length (CRL), biparietal diameter (BPD), head circumference (HC), and abdominal circumference (AC) were made at specified intervals of 2 to 3 weeks (between 6 to 8 weeks [conceptual age] and delivery) in 20 normal fetuses with known dates of conception. Values for the HC-AC ratio and the estimated fetal weight were also obtained from these data. Measurements of CRL were similar to those reported previously, except in those cases in which the follicular phase was prolonged or the fetal growth potential was reduced. Mathematical modeling demonstrated that the linear-cubic model was optimal for the BPD and HC growth curves, the linear model for the AC, and the linear-quadratic model for fetal weight. The HC-AC ratio could not be modeled adequately because of significant individual variability. Optimal models for average longitudinal growth curves were determined for the BPD, HC, AC, and fetal weight from individual growth curves. These average longitudinal curves were similar in shape, mean values, and variability to those obtained in previous cross-sectional studies. Statistical analysis indicated that the coefficients of the average longitudinal curves are not likely to change by more than 5% to 15% if the size of the sample is increased very significantly. These results indicate that the average longitudinal growth curves are good estimators of the true population growth curves.

Adult↗
PubMed1982

Ultrasonically determined menstrual age as an indicator of fetal lung maturity.

The usefulness of ultrasonically determined menstrual age as a predictor of fetal lung maturity has been evaluated in patients without fetal or maternal disease undergoing repeat cesarean section. The menstrual age of each fetus was determined at 18-32 wk using biparietal diameter (BPD) measurements and previously established BPD growth curves. Lung maturity prior to delivery was assessed by measuring the lecithin/sphingomyelin (L/S) in amniotic fluid. The menstrual age at the time of the amniocentesis was derived by extrapolation from the results of the first scan. When the Sabbagha Composite BPD growth curve was used for menstrual age determinations, the L/S was less than 2.0 in all cases before 34 wk, both less than 2.0 and greater than or equal to 2.0 between 34 and 38 wk, and greater than or equal to 2.0 in all but one case after 38 wk. This one case represents 1.2% of fetuses studied. These results suggest that in the absence of fetal and maternal disease, a menstrual age of 38 wk or older, based on an early BPD measurement and use of the Sabbagha Composite BPD growth curve, is indicative of lung maturity in most cases.

Female↗
PubMed1982

Fetal head and abdominal circumferences: I. Evaluation of measurement errors.

Several sources of error associated with the measurement of fetal head and abdominal circumferences (HC, AC) were examined using dynamic image ultrasound. Statistically significant systematic intraobserver errors were not seen unless technical differences in the images were present (HC only) and the range for random errors was 4-5% (2 SD) for both measurements. Although differences in the procedures used to acquire images for measurement had some effect on accuracy (HC only), the primary source of variations in measurements made by different investigators was the measurement methods. Different measuring devices gave different results and different investigators used the same devices differently. Under optimal measuring conditions, the interobserver error for experienced investigators was 1.2 (+/-4.3 SD)% for HC and 2.4 (+/-1.6 SD)% for AC. Comparison of prenatal and postnatal measurements indicated that there were no systematic differences for HC but for AC, the prenatal measurements were 6% greater. Random differences were +/-6% (2 SD) for HC and +/-13% (2 SD) for AC.

Abdomen↗
PubMed1982

Fetal head and abdominal circumferences: II. A critical re-evaluation of the relationship to menstrual age.

Dynamic image ultrasound was utilized to re-examine the changes in head and abdominal circumferences (HC, AC) with gestational age in normal fetuses. Data collected in a cross-sectional study of fetal growth were evaluated using mathematical modeling techniques. The results of this analysis indicated that a linear-cubic function optimally fits the HC data (R2 = 97.3%) while the AC data was fitted optimally by a linear function (R2 = 95.5%). The predicted values calculated from these functions were in very close agreement [mean deviation (absolute value): 1.97% (HC), 1.38% (AC)] with those calculated from average functions for HC and AC obtained in a previous longitudinal growth study. Variability was not constant throughout pregnancy for either HC or AC. With HC the normal range changed from +/-1.5 cm to +/-2.5 cm at 28 wk (menstrual age). The AC variability increased progressively with increasing menstrual age and was shown to be related to the predicted AC value. The normal range was found to be 13% of the predicted AC value throughout pregnancy. Based on these results, a new set of normal HC and AC values for the 12-40 wk (menstrual age) period is presented.

Abdomen↗
PubMed1982

Fetal head circumference: relation to menstrual age.

The relation between fetal head circumference and menstrual age was determined by cross-sectional analysis of 400 fetuses (15-41 weeks) examined with a linear array real-time (dynamic image) scanner using specifically defined methodology. Mathematical modeling of the data demonstrated that the head circumference growth curve is nonlinear, similar to the biparietal diameter growth curve. Both the linear quadratic (r2 = 98.3%) and linear cubic (r2 = 98.3%) functions could be considered the optimal model. Predicted head circumference values for the linear cubic function were comparable to established normal values on the basis of postnatal measurements at 25-40 weeks (mean difference, -0.94 mm; SD, 0.47 mm). Predicted menstrual age values (+/- 2 SD) associated with a given head circumference measurement were calculated and are presented in tabular form. The use of the head circumference measurement in predicting menstrual age, estimating fetal weight, and in detecting intrauterine growth retardation is discussed.

Cephalometry↗
PubMed1982

Fetal biparietal diameter: rational choice of plane of section for sonographic measurement.

In this sonographic study of 100 fetuses (gestational age 15--40 weeks) the maximum transverse diameter of the fetal skull at the axial plane described by Campbell for measurement of the frontooccipital head circumference was compared to similar measurements at specific anatomic planes above and below this level. Transverse diameter measurements at the head circumference level averaged 3 mm (range, 0--9 mm) more than at the level of the superolateral margins of the bodies of the lateral ventricles (where the midline echo is continuous), and 4 mm (range, 0--10 mm) more than at the level of the cerebral peduncles. The head circumference plane is the most appropriate level for measurement of the fetal bipariental diameter (BPD) because (1) the transverse diameter is maximal, (2) unlike the conventional BPD image, this section contains specific anatomic landmarks which should make the BPD measurements technically easier and more reproducible, and (3) stimultaneous measurements of the BPD, frontooccipital head circumference, occipitofrontal diameter, and cephalic index can be obtained.

Cephalometry↗
PubMed1982

Fetal femur length as a predictor of menstrual age: sonographically measured.

The relation between fetal femur length and menstrual age was determined by cross-sectional analysis of 338 normal fetuses (12--40 weeks) using real-time sonography. Mathematical modeling of the data demonstrated that the femur growth curve is nonlinear, similar to the biparietal diameter growth curve. Predicted femur length values at various points in gestation were comparable to the results of other investigators. Predicted menstrual age values in weeks for specific femur length measurements in millimeters were calculated and are reported in tabular form. The variability (+/- 2 SD) associated with predicting menstrual age from femur length is +/- 9.5 days between 12--23 weeks, but between 23--40 weeks the variability is +/- 22 days. Fetal femur length can be used as an adjunct in estimating menstrual age, and as a screening device for diseases that affect fetal limb growth (e.g., dwarfism, osteogenesis imperfecta).

Age Determination by Skeleton↗
PubMed1982

Fetal abdominal circumference as a predictor of menstrual age.

The relation between fetal abdominal circumference and menstrual cycle age was determined by cross-sectional analysis of 400 fetuses (15-41 weeks) examined with a linear-array real-time ultrasound scanner using specifically defined methodology. Mathematical modeling of the data demonstrated that the liner quadratic function was an optimal model (r2 = 97.9%). Predicted abdominal circumference values at specific points in gestation based on this model were comparable to the data reported by other investigators using static-image equipment. Predicted menstrual age values associated with a given abdominal circumference measurement were calculated and are presented in tabular form. The variability (+/- 2 SD) in predicting menstrual age from abdominal circumference measurements is broader than that observed with the fetal biparietal diameter; nonetheless, this measurement can be useful as an adjunct in predicting menstrual age in cases in which the biparietal diameter is technically inadequate or impossible to obtain due to unusual positioning.

Abdomen↗
PubMed1982

Fetal biparietal diameter: a critical re-evaluation of the relation to menstrual age by means of real-time ultrasound.

The relationship between fetal biparietal diameter (BPD) and menstrual age was determined by cross-sectional analysis of 533 fetuses (12 to 40 weeks) examined with a linear array real-time (dynamic image) scanner using specifically defined methodology. Mathematical modeling of the data demonstrated that the optimal fit was the linear cubic function (r2 = 99 per cent); predicted BPD values calculated from the function were most comparable with composite data from cross-sectional studies performed with static scanners after 1974 (average difference, 0.22 mm) and least comparable with composite data from cross-sectional studies performed with static scanners before 1974 (average difference, 2.0 mm). The variability associated with predicting menstrual age from the BPD increased progressively throughout gestation; the maximal variability was noted between 36 and 42 weeks (+/- 3.6 weeks). Comparison with our longitudinal study of BPD growth indicates that the cross-sectional data represent a valid estimate of the true longitudinal BPD growth curve of the population.

Cephalometry↗
PubMed1981

Evaluation of three methods for obtaining fetal weight estimates using dynamic image ultrasound.

The effectiveness of three methods (Campbell and Wilkin, Warsof, Warsof et al for estimating fetal weight from measurements of the abdominal circumference (AC) and biparietal diameter (BPD) has been evaluated in 125 patients studied with dynamic image ultrasound. Investigations of the population as a whole indicated that the Campbell-Wilkin and Warsof methods systematically overestimated the weight (mean deviation: 5.3% and 1.6%, respectively), while the method of Warsof et al gave systematic underestimations (mean deviation: - 3.2%). The variability of the two Warsof methods was similar (SD: 8.8% and 8.4%) and significantly lower than that seen with the Campbell-Wilkin method (SD: 13.9%). When separate weight subclasses (500 gm to 4500 gm) were examined, the mean deviations and their variability were significantly lower with the two Warsof methods. The method of Warsof showed the most consistency among the weight subclasses. These results indicate that of these three methods, the best estimates of fetal weight are provided by the Warsof procedure.

Abdomen↗
PubMed1981

Real-time sonography: ventricular and vascular anatomy of the fetal brain in utero.

Detailed fetal intracranial anatomy can be examined in utero using real-time sonography. The ability to demonstrate motion makes it possible to visualize important vascular landmarks which are helpful in identifying adjacent structures and in recognizing appropriate planes of section. The lateral ventricular system can be demonstrated and the lateral ventricular ratio can be determined in cases beyond 27 weeks gestation if the head is in an occiput transverse position. A lateral ventricular ratio greater than 0.45 (bodies) or greater than 0.65 (atrium) should raise the question of hydrocephalus and close follow-up measurements of the biparietal diameter, the head circumference/abdominal circumference ratio, and the lateral ventricular system should be made to evaluate this possibility. The fetal third ventricle is not routinely visualized before 34 weeks gestation in the absence of hydrocephalus; alternative anatomic explantations for the structure commonly referred to in the literature as the fetal third ventricle are discussed.

Blood Vessels↗