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Biomedical subjects

F P Hadlock

Publications and source records attributed to F P Hadlock.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1981

Estimating fetal age: effect of head shape on BPD.

Several recent obstetrical sonographic examinations in this department demonstrated that variations in the shape of the fetal skull (e.g., dolichocephaly, brachycephaly) may adversely affect the accuracy of the biparietal diameter (BPD) measurement in estimating fetal age. In each case the cephalic index of the fetal skull (short axis/long axis x 100) was in either the dolichocephalic or brachycephalic range based on established postnatal criteria. Consequently, normal values were determined (mean, 78.3) for the cephalic index in utero based on 316 obstetrical sonographic studies performed at 14--40 weeks. Preliminary experience indicates that a cephalic index greater than 1 SD from the mean (less than 74, greater than 83) may be associated with a significant alteration in the BPD measurement expected for a given gestational age, and that the head circumference can be used effectively as an alternative means of establishing gestational age.

Adult↗
PubMed1981

Sonography of fetal urinary tract anomalies.

Experience with 13 cases and a review of 41 cases in English literature indicate that anomalous development of the fetal urinary system can be detected in utero using sonography. Anomalies not compatible with extrauterine life (bilateral renal agenesis, infantile polycystic and bilateral multicystic kidney disease) have distinctive sonographic features that can be detected early enough to allow elective termination. Megacystis, either as a primary finding or secondary to urethral obstruction, can be detected and usually portends a poor fetal outcome. Obstruction at the ureterovesical junction has a distinctive sonographic appearance, but ureteropelvic junction obstruction cannot be differentiated from some cystic renal lesions, particularly when it is unilateral. Even when a precise diagnosis cannot be established in utero, the detection of a fetal renal anomaly may significantly affect obstetric and neonatal management of the benefit of both mother and fetus.

Abnormalities, Multiple↗
PubMed1980

Hypervascularity of the uterine wall during pregnancy: incidence, sonographic appearance, and obstetric implications.

The authors report the incidence (20%) of hypervascularity of the uterine wall (decidual reaction) (1) in 106 pregnant women studied prospectively by ultrasound. An unusual case, which caused problems in diagnosis and management, is reported in detail. The relation between the location and extent of this finding and the location of the placenta is discussed. The authors think that this finding represents dilation of myometrial veins of uncertain etiology, and they conclude that the major implications are that it must be differentiated from pathologic entities that are similar sonographically (1), and that if anterior, it may cause excessive bleeding during invasive procedures.

Adolescent↗
PubMed1980

Unusual radiographic findings in adult pulmonary tuberculosis.

To determine the frequency of unusual chest radiographic findings in adults (older than 15 years) with pulmonary tuberculosis, charts and radiographs of 270 consecutive cases seen in a 12 month period were reviewed. Radiographic findings not typical of primary or postprimary disease (reinfection) were arbitrarily classified as unusual. The incidence of such findings (8%) was considerably lower than in several recent reports (25%, 29%). Likewise, the incidence of lower lobe tuberculosis in diabetics in this population (8.3%) was lower than in a report by Weaver (20%), and the finding of air-fluid levels in patients with cavitary disease (9%) was lower than a report by Cohen (22%). Possible explanations for these discrepancies were reviewed, including: (1) demographic characteristics, (2) the patient selection process, (3) the arbitrary nature of any system of classification of "unusual" findings, and (4) the change in the epidemiology of the disease as a result of chemotherapy and organized eradication programs. Of these, the patient selection process is probably the most significant factor in the discrepancy between the incidence of unusual findings in this series compared with those reported by others.

Adult↗
PubMed1980

Fetal ascites not associated with Rh incompatibility: recognition and management with sonography.

Fetal ascites not associated with Rh incompatibility is an uncommon problem that can be detected in utero by sonography. The sonographer should make a systematic search for the cause of ascites in a given case on the basis of well known etiologic possibilities, since this may have a significant effect on the obstetrical management. The use of sonography in the detection, etiologic evaluation, and obstetrical management of nonimmunologic fetal ascites is discussed, and experience with 10 such cases is reported.

Abnormalities, Multiple↗