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.

https://onlinelibrary.wiley.com/doi/pdf/10.7863/jum.1982.1.3.97

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

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 discu...

Fetal head circumference: relation to menstrual age

Ultrasound has been developed in the last twenty years to become the major instrument for diagnosis of intrauterine growth retardation. However, currently available commercial instruments cannot be used to their full advantage without accurate early ultrasonic measurement of gestational length and without at the same time screening for multiple pregnancy and fetal malformation. Once this has been done, methods that take account of changes in body proportion become less important in the diagnosis of IUGR in later pregnancy and formulas that allow accurate weight categorization can be used with advantage. If an ultrasonic method for screening a whole population is required, then weight-categorization formulas are now well researched and provide an acceptable margin of low false positive rates. The formula should, however, be adapted to give a measure of weight deviation rather than absolute weight so that it can be used over a period of time in pregnancy and not only in a specific week. If a non-ultrasound method is to be used for selecting a population at higher risk, conventional risk criteria (Hobel et al, 1973) and symphysisfundus measurements are valuable. Ultrasound fetometry may then be used with very high sensitivity to improve the identification of those fetuses at risk, but critical evaluation of the use of ultrasound in this situation is still needed. The basic measurement techniques of BPD and fetal trunk measurements singly or combined into weight prediction formulas could then, in larger reference laboratories, be supplemented by ancillary ultrasonic means of investigating fetal growth and fetal well-being. An adverse fetal environment preceding measurable growth retardation of the fetus itself can possibly be reflected in a decrease of intrauterine volume and amniotic fluid and changes of fetal well-being could be investigated by means of changes in volume parameters, fetal activity or fetal blood flow. The next steps towards improved ultrasonic evaluation of IUGR fetuses are likely to be in this direction, while increased IUGR detection will mainly result from better screening techniques.

Diagnosis of intrauterine growth retardation using ultrasound.

W e prospectively evaluated use of a miniature handheld 2-dimensional cardiac ultrasound device in the initial evaluation of acutely ill cardiac patients to test whether immediate cardiac imaging with such an instrument was useful in the cardiologist’s evaluation of the patient. Our hypothesis was that the miniature unit, despite its limited cardiac imaging ability, would provide clinically useful data conveniently. The study group consisted of 64 consecutive acutely ill patients evaluated by the cardiology critical care team over a 2-month period. All patients had an echocardiogram using the miniature device as part of their initial evaluation by a cardiologist (KQS). This evaluation included a history, physical examination, electrocardiogram, chest roentgenogram and routine blood work. In all patients, the miniature unit was the initial cardiac imaging tool used (except chest roentgenography in some cases). After each full evaluation and before additional cardiac imaging, the examining physician recorded a subjective assessment as to whether the study device provided information that answered the primary clinical question and therefore injluenced diagnostic or management plans. Confirmatory diagnostic data were sought within 3 days of admission (using cardiac catheterization with ventriculography, radionuclide angiography, standard echocardiography or Swan-Ganz catheterization). The study device was a 5-pound, battery powered, mechanical sector scanner, about the size of a hardbound book, with standard sized 3.5and ~-MHZ transducers (ScanMate, Damon Corp.) (Figure I). The rechargeable battery allowed approximately 30 minutes of continuous use. The 4.5 X 3 cm screen has 1 -cm scale dots on the edges of the image as the only on-screen help function. Controls are limited to on-off, gain, sector angle (40 to 80 continuously adjustable) and depth (10 to 18 cm). There are no capabilities for freeze frame, electrocardiogram display, M-mode, Doppler or hardcopy/video recording. Photographs of the screen can be made with a modified Polaroid camera. An example of an image obtained with the miniature unit is shown in Figure 2. A total of 71 studies was completed on 64 patients over a 2-month period. The time required to complete a study averaged <lo minutes (no time is spent making hard copies, video recording or performing M-mode or Doppler). All imaging was performed from standard parasternal, apical and subcostal windows. Images adequate to address the primary clinical question, such as wall motion in acute myocardial infarction, were ob-

Experience rounding with a hand-held two-dimensional cardiac ultrasound device

Blinded comparison of an "ultrasound stethoscope" and standard echocardiographic instrument.

Recently a hand-held two-dimensional linear array ultrasound diagnostic system was introduced. To assess the clinical usefulness of this non-invasive system in pediatric echocardiography, an evaluation study was carried out. For this purpose 58 children up to the age of 18 yr were examined. Several of them were known to have a congenital cardiac malformation. The assessment has been based on the image quality of six cardiac structures which include the aortic root, left atrium, right ventricle, interventricular septum, left ventricle and mitral valve. The results indicated differences between children younger than 1 yr and those who are older. Therefore the patients were divided into two groups. In the younger children, only three cardiac structures, the aortic root, left atrium and mitral valve, were recognized with a score above 80%, whereas the remaining structures received a score of 60% or lower. In the older age group the results were much better, as all six cardiac structures were visualized with a score of 80% or more.

Clinical evaluation of a hand-held ultrasound device in pediatric cardiology

A comparative study between a linear-array real-time hand-held scanner (Minivisor) and a conventional scanner (Diasonograph) in the assessment of the fetal biparietal diameter (B.P.D.) is presented. A total of 160 patients between 15 and 41 weeks of gestation was included in the study. A good correlation between both measurements was obtained. The reproducibility of the B.P.D. measurement was better and the scanning time considerably shorter when using the Minivisor. It seems therefore that the Minivisor is a potentially useful portable device for screening of an obstetric population.

A comparative study between a linear-array real-time hand-held scanner (minivisor) and a compound scanner (diasonograph) in the measurement of the fetal biparietal diameter

J.H. Eggink

Papers

Clinical evaluation of a hand-held ultrasound device in pediatric cardiology

A comparative study between a linear-array real-time hand-held scanner (minivisor) and a compound scanner (diasonograph) in the measurement of the fetal biparietal diameter