Accurate ultrasonic biometry in pseudophakia.
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Anthropometry↗
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Amniotic fluid and maternal characteristics in Chinese pregnancies dated by early ultrasound biometry.
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Adult↗
Changes in mussel biometry on exposure to metals: implications in estimation of metal bioavailability in 'Mussel-Watch' programmes.
The occurrence of changes in flesh and shell weights and in other biometric parameters of mussels, Mytilus galloprovincialis, has been related to different metal levels found in their soft tissues. The effects of clean and Zn-polluted environments and laboratory experiments where Zn-polluted mussels were exposed to sublethal concentrations of Zn, Cu and Cd were investigated. Zinc-polluted mussel shell weights increased significantly after a 51-day depuration period. Exposure of Zn-polluted mussels to Zn or Cd, however, caused a slightly reduced shell growth in comparison with depurating mussel Cu-exposures not causing any reduction in growth. Apart from metal concentrations, metal/shell weight indices have been used to assess metal bioavailability. Metal concentrations recorded in the soft tissues of depurating mussels increased without a source of 'extra' metals, while the Zn/shell-weight index was reduced, as expected from a depuration process, Cu and Cd/shell-weight indices remaining constant. Experimental exposure to Zn, Cu and Cd caused augmented values of Zn, Cu and Cd/shell-weight indices, respectively. These different findings were attributed to changes in flesh weight (related with gamete spawning) that would produce inconsistent estimates of whole metal concentration in soft tissues. Since changes in the tissue composition and in growth rates do not affect Zn/Cu ratios and metal/shell-weight indices, these parameters are proposed as reliable indices of metal bioavailability for 'Mussel-Watch' monitoring programmes. The most sensitive parameter is the metal/shell-weight index, which is, therefore, highly recommended to be used in 'Mussel-Watch' monitoring programmes in order to determine metal bioavailability in seawaters.
Animals↗
Measurement of anterior chamber diameter and biometry of anterior segment by Scheimpflug slitlamp photography.
Twenty-eight fresh donor eyes (Georgia Lions Eye Bank) ranging in age from four months to 87 years were used for an in vitro study to determine the feasibility of obtaining accurate anterior chamber diameter measurements with our Scheimpflug ultraviolet-visible slitlamp densitography apparatus. The in vivo study was performed on 16 hybrid monkeys (of varying age). These data were within 0.1 mm of measurements obtained with a modified paracentesis needle specially designed to obtain such measurements (sensitivity within 0.01 mm). The results of the foregoing study demonstrate that the Scheimpflug slitlamp photographic analyses can provide an accurate measurement of the anterior chamber diameter without entering the globe surgically. This will enable the surgeon to determine the diameter and order an anterior chamber IOL of a specified size prior to surgery. We have devised an automated program to analyze the negatives and provide direct anterior chamber diameter measurements.
Adult↗
Transvaginal fetal biometry in early pregnancy.
OBJECTIVE: To produce reference charts for fetal size with transvaginal sonography that are potentially helpful in evaluating normal and abnormal early pregnancies. DESIGN: A prospective cross-sectional study. SUBJECTS: 1081 normal singleton pregnancies with a normal fetal karyotype or normal healthy baby at delivery, at 9-16 weeks' gestation. Measurements included crown rump length, biparietal diameter, transverse cerebellar diameter, head and abdominal circumference, mean abdominal diameter, thoracic circumference, femur length, humerus length and foot length. RESULTS: The best description of the relationship between single ultrasonographic parameters and gestational age was achieved by polynomial regression analysis. All fetal biometric parameters correlated closely with gestational age. Biparietal diameter maintained the closest correlation with gestational age (r2 = 97.15, p < 0.001; y = -0.545 - 0.06x + 0.15x2); transverse cerebellar diameter showed the poorest correlation with gestational age (r2 = 88.17, p < 0.001). Reference ranges (5 degrees and 95 degrees percentile intervals) were constructed for all biometric parameters in relation to gestational age. Mean residuals are similar for all parameters with a very low range. CONCLUSIONS: These data provide normograms for first and early second trimester fetal measurements which may be of aid in the dating of pregnancies and can be useful in the early detection of genetic disorders affecting the growth of fetal structures.
Anthropometry↗
Biometry of the capsular ligaments of the wrist.
The aim of our study was to measure the length, width and inclination in the coronal plane of the capsular ligaments, and to express these measurements as a ratio in order to determine the correlation between these parameters and the bone index. The capsular ligaments were studied from 15 cadaveric upper limbs. We identified 11 volar and 2 dorsal intracapsular ligaments. For each ligament, we measured the length to its middle and to its proximal and distal edge, the width at its average portion, and the inclination in the frontal plane. There was a difference between the proximal or distal length and the middle length for four ligaments. In these cases, however, there was a significant correlation between the proximal or distal length and the middle length. The length of capitate, the length of the third metacarpal bone, and the carpal height were significantly correlated with four ligaments. There were correlations between the length of one ligament and that of all others. There was no correlation between the inclination of the radius and the inclination of ligaments in the coronal plane. Nevertheless, there were six significant correlations between the inclination of one ligament and that of all others.
Aged↗
Heart biometry and allometry in rats submitted to nitric oxide synthesis blockade and treatment with antihypertensive drugs.
Fifty mature male rats were separated into groups of ten rats each (control, L-NAME, spironolactone, enalapril and verapamil). On the 41st day of experimentation, animals were anesthetized, weighed and sacrificed. The tail blood pressure (TBP) was 76% higher in L-NAME group than in the control group. Spironolactone, enalapril and verapamil were efficient in reducing TBP in those respective groups of rats (spironolactone was less efficient in reducing TBP). The heart mass/body mass ratio (HBR) increased 24% in L-NAME group and spironolactone group. No differences in HBR were found when control animals and animals treated with enalapril and verapamil were compared. Heart volume (HV) was greater in L-NAME group than other groups, but it was not different comparing the L-NAME and the spironolactone groups. The left ventricle was responsible for the changes in the HV. The relationship between the HV and the body mass (BM) was not significant in the groups L-NAME and spironolactone. However, this relationship was significant and allometric in control, enalapril and verapamil groups. In control group, HV had a positive allometric tendency against the BM, but in the enalapril and verapamil groups this tendency was allometrically negative. Cardiac hypertrophy in rats under inhibition of NO synthesis was prevented by treatment with enalapril and verapamil more efficiently than spironolactone.
Animals↗
Axial length biometry in infants with retinopathy of prematurity.
Ultrasound axial length measurements were obtained on infants under a birthweight of 1500 g or 32 weeks gestation undergoing screening for retinopathy of prematurity (ROP). A total of 496 readings were obtained on 171 infants between 32 and 41 weeks post-conceptual age. Other details recorded were maximum stage of acute ROP, birthweight, gestational age, sex, and biparietal and occipitofrontal head diameters. The relationship of these variables to axial growth of the eye was examined using analysis of covariance with a repeated measures approach. Mean axial length increased from 15.27 mm to 16.65 mm in the left eye during this period. Following adjustment for repeated readings a growth rate of 0.18 mm/week was obtained for both eyes. Male infants were found to have longer axial lengths despite correction for birthweight, gestation and head size (p < 0.0001 right and left). Higher stages of acute ROP were also associated with shorter axial length (p < 0.05 for all stages of both eyes) but the rate of growth during the study period did not demonstrate significant differences between stages. Stage 3 infants reaching the threshold for cryotherapy had shorter axial length than stage 3 infants not receiving treatment. The effect of prematurity on the growth of the eye and the significance of these findings with respect to the subsequent development of refractive errors in premature infants are discussed.
Analysis of Variance↗
Biometry of early pregnancy with transvaginal sonography.
A prospective cross-sectional study was performed in 248 pregnant women between 5 and 12 weeks' menstrual age with transvaginal sonography to establish biometric charts of the gestational sac, embryonic crown-rump length and biparietal diameter, amniotic sac and yolk sac to be used for assessment of gestational age and prediction of pregnancy failure. Polynomial regression analysis was applied and demonstrated a statistically significant positive correlation that could be described in all cases as a quadratic function, between gestational age and all the measurements with the exclusion of the yolk sac. Centile charts of both growth models and dating models were tabulated. The interrelationship between different measurements, including the gestational sac, crown-rump length, biparietal diameter and amniotic sac was also evaluated to produce age-independent charts. The dating model of the crown-rump length was found to have mean values similar to those described in transabdominal studies. The 95% reference interval was, however, 8.4 days, which was not lower than those reported in most transabdominal studies. It was concluded that transvaginal sonography was more able than the abdominal route to allow measurement of the crown-rump length in very early gestation, but did not yield a greater accuracy in predicting gestational age.
Journal Article↗
Fetal biometry at 14-40 weeks' gestation.
Normal ranges for a wide variety of biometrical parameters were established from cross-sectional data on 1040 normal singleton pregnancies resulting in livebirth at term of normal, and appropriately grown infants. Patients were selected so that the birth weight distribution was similar to that reported by Yudkin and colleagues' and the ranges can, therefore, be used for any population that has a similar birth weight distribution.
Journal Article↗
Can transvaginal fetal biometry be considered a useful tool for early detection of skeletal dysplasias in high-risk patients?
OBJECTIVE: To evaluate the possibility of an early diagnosis of skeletal dysplasias in high-risk patients. METHODS: A total of 149 consecutive, uncomplicated singleton pregnancies at 9-13 weeks' amenorrhea, with certain menstrual history and regular cycles, were investigated with transvaginal ultrasound to establish the relationship between femur length and menstrual age, biparietal diameter and crown-rump length, using a polynomial regression model. A further eight patients with previous skeletal dysplasias in a total of 13 pregnancies were evaluated with serial examinations every 2 weeks from 10-11 weeks. RESULTS: A significant correlation between femur length and crown-rump length and biparietal diameter was found, whereas none was observed between femur length and menstrual age. Of the five cases with skeletal dysplasias, only two (one with recurrent osteogenesis imperfecta and one with recurrent achondrogenesis) were diagnosed in the first trimester. CONCLUSIONS: An early evaluation of fetal morphology in conjunction with the use of biometric charts of femur length against crown-rump length and femur length against biparietal diameter may be crucial for early diagnosis of severe skeletal dysplasias. By contrast, in less severe cases, biometric evaluation appears to be of no value for diagnosis.
Achondroplasia↗
[Transvaginal ultrasound biometry in early pregnancy--a growth model].
PURPOSE: Evaluation of a growth model for the biometric parameters of early pregnancy: Chorionic cavity, yolk sac, amniotic cavity, crown-rump length and biparietal diameter. METHOD: 618 clinically well-dated singleton pregnancies of the first trimester were measured in a prospective cross-sectional study with high-frequency transvaginal ultrasound between 28 and 94 days post menstruation. RESULTS: Normal curves (5th, 50th, 95th percentiles) for all parameters were established using our growth model. The growth curves of chorionic cavity amniotic cavity, and biparietal diameter showed a linear growth whereas the growth curve of the crown-rump-length represented an exponential curve. Linear growth of the yolk sac was found until 8 weeks of gestation and there was no growth alteration after this time. CONCLUSION: With our growth curves of the first trimester it is possible to monitor the embryonic development with several parameters.
Anthropometry↗
[Cephalic index: a neglected parameter of standard fetal biometry].
From 1.1.1990 to 15.3.1991, in 1074 women between the 13th and 40th weeks of pregnancy, the biparietal diameter (BIP), fronto-occipital diameter (FOD) and kephalic index (KI = BIP/FOD) were measured. The median of the kephalic index varied between 0.81 and 0.84 during different pregnancy weeks, with a range between 0.67 and 1.00. Correction to normokephaly (KI = 0.84) produced differences of up to 10 mm to measured values of BIP. We believe it necessary to determine the kephalic index in each kephalometry and to correct the measured value of BIP at least in those cases where the measured kephalic index differs significantly from normokephaly (KI = 0.84).
Female↗
[Current scanning and biometry equipment in ophthalmologic ultrasound diagnosis].
The development of ophthalmological sonographic equipment started as early as 1958 with the ultrasonic "slit lamp" of Baum and Greenwood. This was an immersion-type device with a closed membrane. Subsequent developments took place mainly after the introduction of the contact B-scanner by Bronson and Turner approximately 10 years ago. The instrument designed by them still serves as a source of inspiration for the creation of many "small-part" scanners. Among the special display modes featured in ophthalmological equipment, we have the deflection-modulated B-image (AB-mode) and the so-called "continuous-vector" mode for the A-trace selection from a real time B-mode image. Other examples are the specially designed A-mode equipment for measurement of the axial length of the human eye, and the A-mode equipment with a more or less standardized-gain characteristic curve of the overall amplification.
Anthropometry↗
[Biometry of the large bones of fetal extremities in the 3d trimester].
Ultrasound measurement of head, thorax and the limb bones femur, tibia, humerus and radius was made of 285 fetuses with known gestational age. In addition measurements of the fibula were obtained in 120 fetuses and of the ulna in 125 fetuses. With the use of these data a normal growth curve for each limb bone was established, which can be helpful in detecting late fetal limb malformations as heterozygous achondroplasia. All limb bones show a nearly linear growth rate so that the length of the bones can alternatively be used to determine gestational age. The linear relationship between growth of the limb bones and the fetal head can be used to diagnose fetal head malformations as microcephaly.
Arm↗
A longitudinal study of fetal head biometry.
In this paper the results gathered in a longitudinal ultrasound study (LS) of fetal growth are presented. The study is unusual in design because of its homogeneity, the number of parameters recorded, the exact spacing between the examinations, and the number of examinations per subject. Information not available in the usual cross-sectional studies (CSS) are reported. They include: improved fit of equations with better description of extreme values; absence of increase of the standard deviation, which is in sharp contrast with the CSS published to date; and analyses of growth velocity that are not available in CSS. The parameters that will be reported in this section include the biparietal (BPD), the occipitofrontal (OF), the head perimeter (HP), and the cephalic index (Cl).
Cephalometry↗
[Biometry of the anterior chamber of the eye in Nd:YAG laser iridectomy].
In a prospective clinical study covering 41 eyes (28 patients) with narrow-angle glaucoma the central and peripheral anterior chamber depths were determined biomicroscopically before and after Nd:YAG laser iridectomy. In 29 eyes the central anterior chamber depth was also measured by ultrasonography. In contrast to the increase in central anterior chamber depth, which was only slight, the increase in the peripheral anterior chamber depth was statistically significant (P less than 0.01).
Anterior Chamber↗
[Application and results of biometry of the eye in implantation of intraocular lenses].
Before extracapsular cataract surgery with implantation of a Binkhorst four-loop lens, keratometric readings were taken and anterior chamber depth was measured with a pachometer in 52 patients. The axial eye length was determined with A-scan echography using the Kretz technique 7200 MA unit with a 8 MHz probe and the immersion technique. The biometric control after surgery showed no change in the spherical equivalent of keratometric values. The mean anterior chamber depth was 3.19 mm (+/- 0.3 mm). No systematic correlation between anterior chamber depth before and after surgery was found. The dependence of the change in anterior chamber depth (DVK) on the cataract thickness (L) is described by the linear regression DVK = 2.22 mm - 0.47 L with a correlation coefficient as low as 0.68. The remaining refractive error after lens implantation, established by subjective testing, was compared with the calculated values. The calculated lenses were found to be more minus than the corrections required by the patients. We conclude that the calculated lens powers had been overestimated and were therefore myopizing in relation with the established length. If postoperative emmetropia had been aimed at on the basis of biometric data and conventional calculations, however, weaker lens powers would have been chosen with postoperative hypermetropia resulting.
Anterior Chamber↗