Fetal renal volume in normal gestation: a three-dimensional ultrasound study

Bialleleic PKD1 mutations underlie early-onset autosomal dominant polycystic kidney disease in Saudi Arabian families

BACKGROUND

Polycystic kidney disease (PKD) is one of the most common genetic renal diseases and may be inherited in an autosomal dominant or autosomal recessive pattern. Pathogenic variants in two major genes, PKD1 and PKD2, and two rarer genes, GANAB and DNAJB11, cause autosomal dominant PKD (ADPKD). Early onset and severe PKD can occur with PKD1 and PKD2 pathogenic variants and such phenotypes may be modified by second alleles inherited in trans. Homozygous or compound heterozygous hypomorphic PKD1 variants may also cause a moderate to severe disease PKD phenotype.

METHODS

Targeted renal gene panel followed by Sanger sequencing of PKD1 gene were employed to investigate molecular causes in early onset PKD patients.

RESULTS

In this study, we report four consanguineous Saudi Arabian families with early onset PKD which were associated with biallelic variants in PKD1 gene.

CONCLUSIONS

Our findings confirm that PKD1 alleles may combine to produce severe paediatric onset PKD mimicking the more severe autosomal recessive ciliopathy syndromes associated with PKD. Screening of parents of such children may also reveal subclinical PKD phenotypes.

Analysis of renal blood flow and renal volume in normal fetuses and in fetuses with a solitary functioning kidney

OBJECTIVE

To evaluate renal blood flow and renal volume for the prediction of postnatal renal function in fetuses with solitary functioning kidney (SFK).

METHODS

Seventy-four SFK fetuses (unilateral renal agenesis [12], multicystic dysplastic kidney [36], and severe renal dysplasia [26]) were compared with 58 healthy fetuses. Peak systolic velocity (PSV), pulsatility index (PI), and resistance index (RI) of the renal artery (RA) were measured; 2D and 3D (VOCAL) volumes were calculated. Renal length and glomerular filtration rate (GFR) were obtained in SFK children (2 years).

RESULTS

Compared with the control group, the PSV RA was significantly lower in nonfunctioning kidneys and significantly higher in SFK. Volume measurements indicated a significantly larger volume of SFK compared with healthy kidneys. All but 4 children had GFR above 70 mL/min/1.73 m² , and compensatory hypertrophy was present in 69% at 2 years. PSV RA and SFK volume correlated with postnatal renal hypertrophy. No correlation between prenatal and postnatal SFK volume and GFR at 2 years was demonstrated.

CONCLUSION

Low PSV RA might have a predictive value for diagnosing a nonfunctioning kidney in fetuses with a SFK. We demonstrated a higher PSV RA and larger renal volume in the SFK compared with healthy kidneys.

Evaluation of fetal kidney growth using ultrasound: A systematic review

PURPOSE

To determine the role of ultrasound imaging in evaluating fetal kidney growth.

METHODS

MEDLINE, CINAHL and EMBASE databases were electronically searched for studies between 1996 and January 2017 and limited to English language. Studies were included if they reported on an ultrasound technique to assess fetal kidney growth and they were not a case report or case series. There was independent selection of studies by two reviewers in consensus with one other reviewer. Data were extracted by one reviewer in consensus with two other reviewers.

RESULTS

A total of 1785 articles were identified. The full text of 39 of these were assessed for eligibility for inclusion. Twenty-eight studies were then included in the review. Standard two dimensional (2D) fetal renal measurements are easy to perform, however, this review identified that most studies had some methodological limitations. The disadvantage with 2D and three dimensional (3D) fetal renal volumes are that they include the entire kidney and good reproducibility of 3D volumes has not yet been demonstrated. Currently there is limited research on fetal kidney growth in the setting of abnormal fetal growth. Research focussing directly on fetal kidney parenchyma and blood flow is scarce.

CONCLUSIONS

Some nomograms of 2D and 3D fetal kidney size and volume have been developed. Kidney length is the most popular single fetal kidney measurement; however, it does not seem to be a good indicator of growth. In IUGR fetuses, kidney length remained similar to appropriately grown fetuses whereas AP and TS dimensions were significantly decreased. New ultrasound techniques focusing on the parenchyma of the kidney and perfusion to the kidney should be explored as they may provide more meaningful information on kidney development in the fetus and future kidney function.

Intraexaminer and Interexaminer Variability in 3D Fetal Volume Measurements During the Second and Third Trimesters of Pregnancy

OBJECTIVES

To assess intraexaminer and interexaminer reliability of 3-dimensional fetal sonographic measurements.

METHODS

Three-dimensional fetal organ volumes (head, kidney, total thigh volume, and fractional thigh volume) were acquired during the second and third trimesters, with the addition of placental volume in the second trimester, by 2 different experienced, blinded sonographers. Fifty-eight fetuses were examined from 21 to 39 weeks' gestation. Intraexaminer and Interexaminer reliability was assessed with Bland-Altman plots, and their 95% limits of agreement and intraclass correlation coefficients.

RESULTS

The most significant interexaminer error was observed in the second-trimester kidney volume (95% limits of agreement, ± 110%), and the best agreement was for the third-trimester fractional thigh volume (95% limits of agreement, ± 25%) and second-trimester head volume (95% limits of agreement, -7%-25%). Second- and third-trimester intraclass correlation coefficient results were all greater than 0.75, apart from second-trimester kidney volume intraexaminer (0.374) and interexaminer (0.061) measurements, second-trimester placenta interexaminer measurements (0.390), and third-trimester kidney interexaminer measurements (0.647).

CONCLUSIONS

Three-dimensional fetal sonographic volumes of the head, kidney, total thigh, and placenta have limited reproducibility, and improvements in measurement techniques are needed before they can be used routinely to assess fetal growth. The 3-dimensional fractional thigh volume can be reliably obtained in the late third trimester.

Genetic spectrum of Saudi Arabian patients with antenatal cystic kidney disease and ciliopathy phenotypes using a targeted renal gene panel

Background

Inherited cystic kidney disorders are a common cause of end-stage renal disease. Over 50 ciliopathy genes, which encode proteins that influence the structure and function of the primary cilia, are implicated in cystic kidney disease.

Methods

To define the phenotype and genotype of cystic kidney disease in fetuses and neonates, we correlated antenatal ultrasound examination and postnatal renal ultrasound examination with targeted exon sequencing, using a renal gene panel. A cohort of 44 families in whom antenatal renal ultrasound scanning findings in affected cases included bilateral cystic kidney disease, echogenic kidneys or enlarged kidneys was investigated.

Results

In this cohort, disease phenotypes were severe with 36 cases of stillbirth or perinatal death. Extra renal malformations, including encephalocele, polydactyly and heart malformations, consistent with ciliopathy phenotypes, were frequently detected. Renal gene panel testing identified causative mutations in 21 out of 34 families (62%), where patient and parental DNA was available. In the remaining 10 families, where only parental DNA was available, 7 inferred causative mutations were found. Together, mutations were found in 12 different genes with a total of 13 novel pathogenic variants, including an inferred novel variant in NEK8. Mutations in CC2D2A were the most common cause of an antenatal cystic kidney disease and a suspected ciliopathy in our cohort.

Conclusions

In families with ciliopathy phenotypes, mutational analysis using a targeted renal gene panel allows a rapid molecular diagnosis and provides important information for patients, parents and their physicians.

Role of 3-D ultrasound in clinical obstetric practice: evolution over 20 years

The use of 3-D ultrasound in obstetrics has undergone dramatic development over the past 20 years. Since the first publications on this application in clinical practice, several 3-D ultrasound techniques and rendering modes have been proposed and applied to the study of fetal brain, face and cardiac anatomy. In addition, 3-D ultrasound has improved calculations of the volume of fetal organs and limbs and estimations of fetal birth weight. And furthermore, angiographic patterns of fetal organs and the placenta have been assessed using 3-D power Doppler ultrasound quantification. In this review, we aim to summarize current evidence on the clinical relevance of these methodologies and their application in obstetric practice.

Renal volumes measured by 3-dimensional sonography in healthy fetuses from 20 to 40 weeks

OBJECTIVES

The purpose of this study was to establish reference values for fetal kidney volumes as a function of gestational age, estimated by 3-dimensional sonography using the Virtual Organ Computer-Aided Analysis (VOCAL) technique (GE Healthcare, Kretztechnik, Zipf, Austria).

METHODS

Volumes of right and left kidneys were assessed in 213 healthy fetuses by 3-dimensional sonography using the VOCAL technique. Inclusion criteria were healthy women with singleton pregnancies, unremarkable comprehensive fetal sonographic findings, well-known gestational age established by first-trimester sonography, and gestational ages between 20 and 40 weeks. Exclusion criteria were patients lost to follow-up and birth weight abnormalities. Each patient was scanned once during pregnancy. Regression analysis was used to calculate unified formulas.

RESULTS

The mathematical models calculated in the study were as follows: expected right kidney volume = exp[-1.01 + (0.12 × gestational age)]; and expected left kidney volume = exp[-0.90 + (0.12 × gestational age)]. No significant intraobserver or inter-observer variability was observed for the determined volumes.

CONCLUSIONS

Reference values for right and left fetal kidney volumes throughout gestation using the rotational technique (VOCAL) are described. The use of this technique might aid in further definition of gestational age kidney volume standards to help in defining variations from the norm.

Size and volume charts of fetal kidney, renal pelvis and adrenal gland

OBJECTIVE

To establish reference curves for size and volume of the fetal kidney, renal pelvis and adrenal gland, as measured using ultrasound from the 15(th) week of gestation.

METHODS

This was a prospective, longitudinal study of 96 fetuses in low-risk singleton pregnancies, in which we performed serial ultrasound examinations at 4-week intervals. The length and anteroposterior and transverse diameters of both kidneys, the anteroposterior and transverse diameters of the renal pelvises and the length of the adrenal glands were measured three times at each examination, with the average being used for further analysis. Reference charts were constructed using multilevel statistical analysis and comparisons were made with previously published charts derived from cross-sectional data.

RESULTS

We present nomograms for fetal kidney dimensions and volume, renal pelvis dimensions and adrenal gland length. The new charts show differences in shape and have narrower percentile bands in comparison to previously published reference ranges.

CONCLUSIONS

These new charts of measurements of the fetal kidney, renal pelvis and adrenal gland, from a prospective, longitudinal study, may be useful in the diagnosis and assessment of pathology of the kidney and adrenal gland.

Body-surface-area related renal volume: a common normal range from birth to adulthood

Renal volume is an important parameter of renal development. Deviations from normal volume may indicate pathologic conditions. Thus, during childhood, the ever changing renal volumes require the continuous referral to normal volume charts in order to classify actual volumes, which is rather inconvenient. In daily practice this is frequently disregarded and kidneys are evaluated by their appearance only. Therefore, we tested the hypothesis that body surface area (BSA) and renal volume grow proportionally from birth to adulthood. We divided the renal volume of a child by its BSA to get the BSA-related renal volume (BSARV) and found no differences between left and right kidneys and a normal distribution for all kidneys regardless of the patient's age. BSARV has a common normal range for all age groups with the 10th percentile of 45 and the 90th percentile of 85 mL/m(2). 80% of all kidneys do not exceed the volume of their counterparts by more than 20%. BSARV alleviates the correct evaluation of a child's renal volume regardless of age and reveals pathological influences by the simple observation that a kidney deviates from a former percentile or z-value. This is especially valuable in the followup of kidneys with chronic diseases.

The morphometric development and arterial vascularization of bovine fetal kidneys in the prenatal period

This study presents a morphometric developmental analysis of bovine kidneys and a demonstration of intrarenal arterial vascularization in the prenatal period. A total of 40 Holstein bovine fetuses constituted the material of the study. The fetuses were divided into three groups, according to the gestational stages they belonged to early, mid- and late stages, such that each group comprised 10 fetuses. Sixty kidneys and their renal arteries were evaluated using morphometric measurements. Furthermore, 10 bovine fetuses were injected with cast solution to demonstrate the intrarenal arteries. Data obtained in the present study were statistically analyzed. Although the right and left kidneys did not significantly differ from each other, significant differences existed between the different gestational stages (P<0.05). The kidney parameters, including length, width and thickness, were positively correlated with both the right and left kidneys as well as with gestational age. Four types of intrarenal arterial segmentation were demonstrated. Type I was observed in 10 kidneys (50%), type II in four kidneys (20%) as well as type III, and type IV in only two kidneys (10%). In the most frequent arterial segmentation type (type I), the renal artery divided into three segmental arteries, which supplied the cranial polar, medial and caudal polar regions of the kidney, after stemming from the abdominal aorta. Furthermore, cases of double and multiple renal arteries were also observed.

A review of fetal volumetry: the need for standardization and definitions in measurement methodology

Volume charts of fetal organs and structures vary considerably among studies. This review identified 42 studies reporting normal volumes, namely for fetal brain (n = 3), cerebellum (n = 4), liver (n = 6), femur (n = 2), lungs (n = 15), kidneys (n = 3) and first-trimester embryo (n = 9). The differences among median volumes were expressed both in percentage form and as standard deviation scores. Wide discrepancies in reported normal volumes make it extremely difficult to diagnose pathological organ growth reliably. Given its magnitude, this variation is likely to be due to inconsistencies in volumetric methodology, rather than population differences. Complicating factors include the absence of clearly defined anatomical landmarks for measurement; inadequate assessment and reporting of method repeatability; the inherent difficulty in validating fetal measurements in vivo against a reference standard; and a multitude of mutually incompatible three-dimensional (3D) imaging formats and software measuring tools. An attempt to standardize these factors would improve intra- and inter-researcher agreement concerning reported volumetric measures, would allow generalization of reference data across different populations and different ultrasound systems, and would allow quality assurance in 3D fetal biometry. Failure to ensure a quality control process may hamper the wide use of 3D ultrasound.

Reproducibility of fetal renal pelvis volume measurement using three-dimensional ultrasound

OBJECTIVE

To assess the reproducibility of fetal renal pelvis volume measurement in hydronephrotic kidneys using transabdominal three-dimensional (3D) ultrasound.

METHODS

The fetal renal pelvis volume was measured using 3D ultrasound in one kidney in each of 15 fetuses with hydronephrosis in the second or third trimester of pregnancy. Hydronephrosis was diagnosed when the fetus had an anteroposterior renal pelvis diameter > or = 5 mm. After volume acquisition by one of the observers, the repeatability of volume calculation with manual delineation of the fetal renal pelvis was assessed by six different observers using the Virtual Organ Computer-aided AnaLysis (VOCAL(trade mark)) imaging program. The intraclass correlation coefficients (ICC), coefficient of variation (CV) and within- and between-observer repeatability coefficient (r) were calculated and Bland-Altman plots were constructed.

RESULTS

Both intra- and interobserver reliability of the fetal renal pelvis volume measurements were considered to be very good. For intraobserver reliability, the ICC was 0.996 and the CV was 10.8%. For the overall interobserver reliability, the ICC was 0.998 and the CV was 15.7%; the interobserver reliability between pairs of observers had ICCs between 0.994 and 0.999, and CVs between 19.5% and 7.6% for inexperienced and experienced observers, respectively.

CONCLUSION

With 3D ultrasound using the VOCAL imaging program, it is technically feasible to reproduce fetal renal pelvis volume measurements. Further research to establish the clinical applications of this technology is warranted.

Predicting fetal growth restriction with renal volume using 3-D ultrasound: efficacy evaluation

Early detection and management of fetal growth restriction (FGR) is very important in prenatal care and daily practice, because FGR fetuses may suffer increased risk of perinatal morbidity and mortality. Renal volume (RV) might be one of the important parameters of fetal growth. Yet, no prenatal assessment of fetal RV in FGR fetuses by 3-D ultrasound (US) has been reported. We undertook a prospective and cross-sectional study using quantitative 3-D US to assess the efficacy of fetal RV in predicting FGR. All fetuses were singletons and were followed-up to delivery to determine whether they had FGR complications. In total, 221 fetuses without FGR and 28 fetuses with FGR were included. Our results showed fetal RV assessed by 3-D US can differentiate fetuses with FGR from fetuses without FGR. The best predicting threshold for FGR is at the tenth percentile of fetal RV. Using the tenth percentile as the cutoff, the efficacy of fetal RV in predicting FGR was sensitivity 96.4%, specificity 95.9%, positive predictive value 75.0%, negative predictive value 99.5% and accuracy 96.0%, respectively. Fetal RV assessed by 3-D US can be applied to detect FGR prenatally. We believe fetal RV assessment using 3-D US is a useful test in detecting fetuses with FGR.

Three-dimensional ultrasonography can detect the modulation of kidney volume in two-kidney, one-clip hypertensive rats

As volume changes are a typical finding in the two-kidney, one-clip hypertensive rat model (2K1C), it is of interest to investigate within what time frame these volume changes occur and their relation to hypertension. Kidney volume changes in Wistar rats were measured by three-dimensional (3D) ultrasonography (USG). Clipped induced stenosis was applied to the left renal artery in 11-wk-old animals (n = 8), using age-matched nonclipped rats as controls (n = 7). Ultrasonographic recordings were made before clipping and, thereafter, weekly with corresponding systolic blood pressure and body weight measurements. The nonclipped kidney showed increased volume at week 2, 5 and 7. Three wk after clipping, clipped kidneys were smaller than the nonclipped kidneys (0.47 +/- 0.11 mL versus 1.28 +/- 0.07 mL). No difference was found between the left and right kidney in the control group at any week. Blood pressure was significantly higher in the 2K1C hypertensive group 4 weeks after clipping (201 +/- 16 versus 139 +/- 4 mm Hg) with stable blood pressure thereafter. Three-dimensional USG showed that clipping caused a decrease in kidney volume from week 3 in the clipped kidney and a volume increase in the nonclipped kidney at week 2. A significant increase in blood pressure appeared after week 4.

Three-dimensional sonographic volume measurement of the fetal spleen

AIM

The objective of this longitudinal study was to evaluate the growth of the fetal spleen in normal pregnancies, using three-dimensional ultrasound.

METHODS

Three-dimensional sonographic examinations were performed on 14 appropriate-for-gestational-age fetuses. Fetal splenic volume was measured every 2-3 weeks after 20 weeks of gestational age until delivery.

RESULTS

Curvilinear relationships were found between the gestational age and splenic volume (R(2) = 80.2%, P < 0.0001), and normal ranges of splenic volume measurements for estimating the growth of the fetal spleen during normal pregnancy were generated. We found that the splenic volume calculation based on the equation for the volume of the ellipsoid by conventional two-dimensional ultrasound in previous investigations is about twice as large as that using three-dimensional ultrasound in our study, whereas the present data described in this study is quite comparable with previous data from an autopsy series.

CONCLUSION

Our findings suggest that the standard curve for the fetal splenic volume using three-dimensional ultrasound provides a superior means for evaluating the normal splenic growth in the fetus and for identifying splenic abnormalities in utero. However, the data and its interpretation in our study should be taken with some degree of caution because of the small number of subjects studied. Further studies involving a larger sample size would be needed to confirm these findings.

Nomogram of fetal renal growth expressed in length and parenchymal area derived from ultrasound images

PURPOSE

We constructed nomograms of fetal renal length and parenchymal area derived from ultrasound images to develop a standard for normal fetal renal growth.

MATERIALS AND METHODS

Longitudinal and transverse ultrasound renal images from 216 normal fetuses (16 to 41 weeks of gestation) were evaluated to construct growth charts. We measured the parenchymal area as well as the longitudinal and transverse lengths of each kidney using computer software for image analysis. Data were separately plotted as a mean +/- 2 SD determined by polynomial regression analysis.

RESULTS

Nomograms for a renal growth chart were constructed independently for the right and left fetal kidneys. No statistically significant difference was noted between the right and left renal measurements. The polynomial regression equations for the left renal longitudinal length and parenchymal area, respectively, were y = -0.0002x(3) + 0.0139x(2) - 0.2162 x 2.3929 (r(2) = 0.9842), and y = -0.0009x(3) + 0.0724x(2) - 1.5643 x 11.68 (r(2) = 0.9779). The longitudinal and transverse fetal renal growth curves displayed significant growth associated with gestational age (p <0.001). Our data on left longitudinal renal length exhibited an intermediate level compared to 2 published Western growth charts. However, statistical comparisons revealed the differences were partially, but not universally, significant.

CONCLUSIONS

We present our nomogram of fetal renal growth expressed in length and parenchymal area. To our knowledge this is the first report of a fetal renal growth chart in Asia that includes the parenchymal area. This nomogram may serve as a valuable tool for evaluation of fetal renal growth.

Prenatal detection of fetal growth restriction by fetal femur volume: efficacy assessment using three-dimensional ultrasound

As fetal growth restriction (FGR) may have increased risks with perinatal morbidity and mortality, it is very important to detect FGR prenatally. Fetal femur dysplasia is associated with a variety of congenital syndromes and FGR as well. To date, no prenatal assessment of fetal FV in predicting FGR using three-dimensional (3D) ultrasound (US) has been reported. In this study, we used 3D US to test the efficacy of fetal femur volume (FV) measurement in predicting FGR. We calculated the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and efficacy of fetal FV assessed by 3D US in detecting FGR according to the Bayes' theorem. All the fetuses were singletons and were followed up to delivery to determine whether they were complicated with FGR or not. In total, 304 fetuses without FGR and 42 fetuses with FGR were included for FV assessment in utero by 3D US. Our results showed fetal FV assessed by 3D US can differentiate fetuses with FGR from fetuses without FGR well. The best predicting threshold for FGR is at the 10th percentile of FV. Using the 10th percentile as the cutoff, the sensitivity of fetal FV in predicting FGR was 71.4%, specificity 94.1%, positive predictive value 62.5%, negative predictive value 96.0% and accuracy 91.3%. In addition, fetal FV is superior to fetal biparietal diameter and fetal abdominal circumference in predicting FGR. In conclusion, fetal FV assessed by 3D US can be applied to detect FGR well prenatally. We believe fetal FV assessment by 3D US would be a useful test in detecting fetuses with FGR.

Age-Related Changes of the Human Fetal Kidney Size

Early prenatal diagnostics and the importance of genetic counseling are of great interest for echosonographic evaluation of normal fetus anatomy. Development of the human fetal kidney runs through a series of continual and mutually dependent changes during which the kidney obtains its morphological and functional maturity. This study was created to estimate the changes in kidney size during gestation in fetuses from the 4th to the 10th lunar month, to evaluate the dynamics of their growth, as well as to establish the validity of the volume calculated from these dimensions. Serial measurements of kidney dimensions (length, width, thickness) were performed in 110 fetuses. Photomicrographs of kidneys from the 4th, 6th, 8th and 10th lunar months are also presented. On the basis of the results obtained by our examination, we concluded that the period from the 14th to 16th week of intrauterine life is the fastest period of kidney growth during fetal development. Using the ellipsoid formula for calculating the fetal renal volume offers an underestimation of about 32-33% on average. The importance of this study lies in determining the average fetal kidney dimensions, which could be used as standard values in obstetrics.

Predicting fetal growth restriction by humerus volume: A three-dimensional ultrasound study

Prenatal diagnosis of fetal growth restriction (FGR) is very important, as FGR may have increased risks with perinatal morbidity and mortality. Fetal humerus dysplasia is associated with a variety of congenital syndromes and FGR. For the assessment of the efficacy of fetal humerus volume in predicting FGR, we undertook a prospective cross-sectional study using quantitative three-dimensional (3D) ultrasound (US). In total, 42 fetuses with FGR and 258 fetuses without FGR were included for the humerus volume assessment in utero by 3D US. All the fetuses were singletons and were followed up to delivery to determine whether they were complicated with FGR or not. Our results revealed that fetal humerus volume assessed by 3D US can differentiate fetuses with FGR from fetuses without FGR well. The best predicting threshold for FGR is at the 10th percentile by humerus volume. Using the 10th percentile as the cutoff, the sensitivity of fetal humerus volume in predicting FGR was 97.6%, specificity 87.2%, positive predictive value 55.4%, negative predictive value 99.6% and accuracy 88.7%. In conclusion, fetal humerus volume assessed by quantitative 3D US can be used to predict FGR prenatally. We believe fetal humerus volume assessment by 3D US would be a useful test in detecting fetuses with FGR.

Fetal upper arm volume in predicting intrauterine growth restriction: a three-dimensional ultrasound study

As fetuses with intrauterine growth restriction (IUGR) may have increased risks with perinatal morbidity and mortality, prenatal diagnosis of IUGR is a very important issue in perinatology. To assess the efficacy of fetal upper arm volume in predicting IUGR, we undertook a prospective, cross-sectional study using quantitative three-dimensional (3D) ultrasound (US). In total, 40 fetuses with IUGR and 442 fetuses without IUGR were included for the upper arm volume assessment in utero by 3D US. All the fetuses were singletons and were followed up to delivery to establish whether they were complicated with IUGR or not. Our results showed that fetal upper arm volume assessed by 3D US can differentiate fetuses with IUGR from fetuses without IUGR well. The best predicting threshold for IUGR is at the 10th percentile by upper arm volume. Using the 10th percentile as the cutoff, the sensitivity of fetal upper arm volume in predicting IUGR was 97.5%, with specificity 92.8%, predictive value of positive test 54.9%, predictive value of negative test 99.8% and accuracy 93.1%. Furthermore, upper arm volume is the best parameter for detecting IUGR among the common fetal biometric indices, such as biparietal diameter (BPD), occipitofrontal diameter (OFD), head circumference (HC), abdominal circumference (AC), femur length (FL) and estimated fetal weight (EFW). In conclusion, fetal upper arm volume assessed by quantitative 3D US can be used to predict fetuses with IUGR antenatally. We believe fetal upper arm volume assessment by 3D US would be a useful test in detecting fetuses with IUGR.

The efficacy assessment of thigh volume in predicting intrauterine fetal growth restriction by three-dimensional ultrasound

Intrauterine growth restriction (IUGR) is an important issue in perinatology. To assess the efficacy of fetal thigh volume (ThVol) in predicting IUGR, we undertook a prospective cross-sectional study using quantitative 3-D ultrasound (US). During the study period, 30 fetuses with IUGR and 282 fetuses with non-IUGR were included for the ThVol assessment in utero by 3-D US. All the fetuses were singletons and had follow-up to the delivery to determine whether they were complicated with IUGR or not. Our results showed fetal ThVol assessed by 3-D US can differentiate fetuses with IUGR from fetuses with non-IUGR well. Using the 10th percentile as the screening threshold, the sensitivity of fetal ThVol in predicting IUGR was 86.6%, with specificity 91.1%, predictive value of positive test 51.0%, predictive value of negative test 98.5% and accuracy 90.7%. In conclusion, fetal ThVol assessed by quantitative 3-D US can be used to predict fetuses with IUGR antenatally. We believe fetal ThVol assessment by 3-D US would be a useful test in detecting fetuses with IUGR.

Growth patterns of the heart and kidney suggest inter-organ collaboration in facultative fetal growth

Maternal smoking during pregnancy has been associated with a number of negative sequelae among offspring, including elevated postnatal blood pressure. While animal studies have described organ level alterations with smoke exposure, human data have been more limited. Thirty-four healthy maternal/fetal pairs (24 nonsmokers, 10 smokers) participated in a longitudinal growth study from the thirteenth week of pregnancy to document fetal kidney and heart growth trajectories and morphology. Curve fitting followed by a mixed model for repeated measures identified significantly different growth patterns in kidney width, thickness, length, and volume growth with exposure: the smoke-exposed fetal kidney was wide and thick compared to the unexposed kidney during the second and early third trimester, declining to proportionately thin kidneys for length and width subsequently. Cardiac growth in width and volume followed a reverse pattern: a surge in cardiac volume occurred after 30 weeks with acceleration in cardiac width, resulting in a heart that was wide for length and for fetal weight. Smoke exposure altered fetal growth in size and timing of the heart and kidneys during midgestation, with changes in organ morphology suggesting compensatory growth. These are the first data providing anatomical evidence of altered renal/cardiac volume relationships that may provide a mechanism to previously reported sequelae of in utero smoke exposure. They suggest that cell-level adaptive responses to hypoxia and/or chemical insults are operative and illustrate the importance of longitudinal ultrasound to directly assess the organ-level growth response of the human fetus to a prenatal stress, in lieu of relying on birth outcome measures.

Growth patterns of human ovarian volume during intrauterine and postnatal organogenesis

BACKGROUND

Ovarian volumes during pre-pubertal, reproductive or menopausal life in a healthy female have been studied by in vivo and anatomical methods. In contrast, conclusive studies on normal human ovarian volume during intrauterine and postnatal organogenesis, when the folliculogenesis occurs, do not exist.

AIM

To assess the growth patterns of ovarian volume during human ovarian definitive histogenesis using morphometric methods.

SUBJECTS

Twenty-five left ovaries removed from fetuses, newborns and children with karyotype 46,XX, ranging from 15 to 74 weeks of development.

OUTCOME MEASURES

The ovaries were completely cut obtaining serial sections. Ovarian volume was calculated both with the ellipsoid method, using its length, maximum and minimum diameters, and the Cavalieri quantitative morphometric method. The age-related pattern of ovarian volume was studied using linear regression analyses.

RESULTS

Ovarian volume calculated with the Cavalieri method increased from 16 mm3 at the 15th week of development to over 300 mm3 at the end of the process, with a 20-fold increase compared to the initial volume. Ovarian volume calculated with the ellipsoid method ranged between 25 to over 380 mm3, with a 15-fold increase. On average, ellipsoidal volume over-estimated the true Cavalieri volume (mean difference -14%, S.D. 29, p=0.014, Student's t-test for paired samples). Linear regression curves were developed to predict ovarian volume at any age. Overall, the approximation was better for Cavalieri volume (approximately, 72% of variance explained by the linear regression) than for ellipsoid volume (59% of explained variance).

CONCLUSIONS

During the intrauterine and postnatal organogenesis, the normal growth rate of human ovary was almost linear. The calculation of ovarian volume using Cavalieri method does not depend on assumptions about the organ shape and it appears to be more appropriate.

Fetal ventricular mass determination on three-dimensional echocardiography: studies in normal fetuses and validation experiments

BACKGROUND

Estimation of ventricular volume and mass is important for baseline and serial evaluation of fetuses with normal or abnormal hearts. Direct measurement of chamber wall volumes and mass can be made without geometric assumptions by 3D fetal echocardiography. Our goals were to determine the feasibility of using fast nongated 3D echocardiography for fetal volumetric and mass assessments, to validate the accuracy of the ultrasound system and the measurement technique, and if satisfactory, to develop normal values for fetal ventricular mass during the second and third trimesters.

METHODS AND RESULTS

This was a prospective outpatient study of 90 consecutive normal pregnancies during routine obstetric services at Oregon Health & Science University (Portland). Optimized 3D volumes of the fetal thorax and cardiac chambers were rapidly acquired and later analyzed for right and left ventricular mass by radial summation technique from manual epicardial and endocardial traces. Experiments to validate the ultrasound system and measurement technique were performed with modified small balloon models and in vivo and ex vivo small animal experiments. Our study established the feasibility of fetal ventricular mass measurements with 3D ultrasound technology and developed normal values for right and left ventricular mass from 15 weeks' gestation to term.

CONCLUSIONS

Nongated fast 3D fetal echocardiography is an acceptable modality for determination of cardiac chamber wall volume and mass with good accuracy and acceptable interobserver variability. The method should be especially valuable as an objective serial measurement in clinical fetal studies with structurally or functionally abnormal hearts.

Application of free-hand three-dimensional echocardiography in the evaluation of fetal cardiac ejection fraction: a preliminary study

OBJECTIVE

To investigate the feasibility of using free-hand three-dimensional (3D) echocardiography to evaluate fetal cardiac function.

METHODS

3D cardiac data were collected during screening examinations for 37 normal fetuses with gestational ages of between 16 and 26 weeks. Processing of the 3D volumes included separation of the end-diastolic and end-systolic slices, segmentation of right and left ventricles, measurement of end-diastolic and end-systolic volumes, and calculation of the ejection fraction (EF) for each ventricle. In 21 fetuses at 21-24 weeks, right and left ventricle volumes and EF were compared.

RESULTS

Twenty-five cases were appropriate for final statistical analysis. The volume of the ventricles increased with gestational age and estimated fetal weight. There was no significant trend in the difference between the volumes and EF of the right and left ventricles in the 21-24-week subgroup. The mean right and left ventricular EF were 54 +/- 11.2% and 57.5 +/- 14.6%, respectively. The mean combined EF of ventricles during gestation was 55.1 +/- 10.7% and seemed to remain constant during the gestational ages studied.

CONCLUSIONS

3D echocardiography can provide estimates of ventricular volume and function and may in future be used for evaluation of fetuses with congenital heart disease and cardiac dysfunction.

Prenatal assessment of normal fetal humerus volume by three-dimensional ultrasound

Because fetal humerus dysplasia is associated with a variety of congenital syndromes, prenatal assessment of the fetal humerus growth is very important. The fetal humerus volume is one of the indexes in evaluating the humerus growth, but it has never been studied by 3-D ultrasound (US) in utero. To establish a normal reference chart of the fetal humerus volume for clinical use, we undertook a prospective and cross-sectional study using 3-D US to assess the fetal humerus volume in normal pregnancy. A total of 216 singleton fetuses that ranged between 20 and 40 weeks of gestation and fit the criteria of normal pregnancies were included in this study. Our results showed that the fetal humerus volume is highly correlated with the gestational age (GA). Using GA as the independent variable and the humerus volume as the dependent variable, the best-fit regression equation was humerus volume (mL) = 0.0044GA(2) - 0.0841GA + 0.6874 (r = 0.97, n = 216, p < 0.0001). For clinical use, a chart of normal growth centiles of the fetal humerus volume was then established based on this equation. In addition, the common indexes of fetal biometry, such as biparietal diameter, occipitofrontal diameter, head circumference, abdominal circumference, femur length and estimated fetal weight, were all highly correlated with the humerus volume (all p < 0.0001). In conclusion, our data of the fetal humerus volume assessed by 3-D US can serve as a useful reference in evaluating the fetal humerus growth during normal gestation.

Three-dimensional power Doppler ultrasound for the assessment of the fetal brain blood flow in normal gestation

Early identification of the abnormal fetal brain vascularization and blood flow is very important, because the deficient perfusion of the fetal brain may be related to a poor prognosis of the central nervous system (CNS) development. To assess the fetal brain vascularization and the blood flow in normal gestation, we measured the fetal brain vascularization and the brain blood flow in normal fetuses using three-dimensional (3-D) power Doppler ultrasound (US) and the quantitative 3-D power Doppler histogram analysis. This study was undertaken by a prospective and cross-sectional design. In total, 155 normal singletons with gestational age (GA) between 21 and 40 weeks were included. The 3-D power Doppler US and the quantitative 3-D histogram analyses were used to assess the fetal brain vascular indexes, i.e., vascularization index (VI), flow index (FI) and vascularization-flow index (VFI), in each case. Our results revealed that all the fetal brain VI, FI and VFI increased significantly with GA (all p<0.001). In addition, the fetal brain VI, FI and VFI were all significantly correlated with the common fetal growth indices, such as biparietal diameter, occipitofrontal diameter, head circumference, abdominal circumference, femur length and estimated fetal weight. Our study indicates that fetal brain vascularization and blood flow increase significantly with the advancement of GA as well as the fetal common growth indices during normal gestation. We believe our data may serve as a reference for further studies of the fetal brain blood flow in abnormal conditions.

The assessment of normal fetal brain volume by 3-D ultrasound

The assessment of the fetal brain volume (BV) is very important in the evaluation of fetal growth. The purpose of this study is to use the three-dimensional (3-D) ultrasound (US) in constructing reference centiles of the fetal BV during normal gestation for clinical application. This study was undertaken by a prospective and cross-sectional design. In total, 203 singleton fetuses ranged between 20 and 40 weeks of gestation and fit the criteria of normal pregnancies were enrolled in this study. Our results showed that fetal BV is highly correlated with the gestational age (GA). Furthermore, using GA as the independent variable and the fetal BV as the dependent variable, the best-fit regression equation was BV (mL)=-171.48036+4.8079xGA+0.29521xGA2 (r=0.99, n=203, p<0.0001), with SD of BV (mL)=1.2533x(9.9474+0.07133xGA). In addition, the common growth parameters of the fetal biometry, such as biparietal diameter (BPD), occipitofrontal diameter (OFD), head circumference (HC), abdominal circumference (AC), femur length (FL) and estimated fetal weight (EFW), were all highly correlated with the fetal BV (all p<0.0001). In conclusion, our data on the fetal BV assessed by 3-D US may serve as a useful reference in evaluating fetal growth.

The assessment of normal fetal liver volume by three-dimensional ultrasound

Liver volume (LIVV) is very important in determining the status of fetal growth. However, to measure human fetal LIVV in utero precisely and noninvasively is not an easy task. With the recent advancement of three-dimensional (3-D) ultrasound (US), the limitation in assessing fetal LIVV by 2-D US can be overcome. The purpose of this study was to establish a normal reference chart of fetal LIVV for clinical use. A prospective and cross-sectional study using 3-D US was undertaken to assess the fetal LIVV in normal pregnancy. In total, 226 singleton fetuses ranging between 20 and 40 weeks of gestation and fitting the criteria of normal pregnancies were enrolled in this study. Our results showed that fetal LIVV is highly correlated with the gestational age (GA). Furthermore, using GA as the independent variable and fetal LIVV as the dependent variable, the best-fit regression equation was LIVV (mL) = -398.26 + 46.199 xGA - 1.7567 x GA(2) + 0.0236 x GA(3) (r = 0.97, n = 226, p < 0.0001), with SD of LIVV (mL) = 1.2533 x (0.77956 + 0.17267 x GA). These common indexes of fetal biometry, such as biparietal diameter (BPD), occipitofrontal diameter (OFD), head circumference (HCi), abdominal circumference (ACi), femur length (FL), and estimated fetal weight (EFW), were all highly correlated with fetal LIVV (all p < 0.0001). In conclusion, our data of fetal LIVV assessed by 3-D US can serve as a useful reference in evaluating fetal growth status during normal gestation.

Quantification of ovarian stromal Doppler signals in postmenopausal women receiving hormone replacement therapy

OBJECTIVE

To investigate the effect of continuous-combined hormone replacement therapy (HRT) on ovarian circulation, we used three-dimensional power Doppler ultrasound to assess ovarian stromal blood flow in postmenopausal women.

DESIGN

Forty healthy, postmenopausal women were enrolled in this prospective, controlled study. They were divided into two groups: the control group (20 patients with no HRT treatment) and the HRT group [initially 20 patients, but later 15 patients who completed the study, using continuous-combined conjugated equine estrogen (0.625 mg/day) plus medroxyprogesterone (5 mg/day)]. All patients underwent transvaginal three-dimensional power Doppler ultrasonography at the time of recruitment and 3 months later. The ovarian stromal flow indices, including vascularization-flow index (VFI), flow index (FI), and vascularization index (VI), were measured. Blood withdrawals for serum follicle-stimulating hormone and estrogen level testing were obtained before and after 3 months of treatment.

RESULTS

All the variables in the hormone profile showed significant difference (P < 0.05) after 3 months of treatment in the HRT group. Of interest, the three-dimensional power Doppler indices of ovarian stromal flow, VFI (0.13 +/- 0.11 --> 0.59 +/- 0.49), FI (30.47 +/- 12.06 --> 38.41 +/- 10.21), and VI (0.31 +/- 0.27 --> 1.12 +/- 0.95) all showed significant increase (P < 0.05) after 3 months of HRT treatment.

CONCLUSIONS

There was a significant increase in ovarian stromal flow indices after 3 months of treatment in the HRT group, but not in the controls. Monitoring the ovarian flow changes by three-dimensional power Doppler may be of clinical importance when HRT is given.

Quantitative three-dimensional power Doppler sonography for assessment of the fetal renal blood flow in normal gestation

Renal blood flow is very important to fetal hemodynamics. To assess the development of fetal renal vascularization and blood flow in normal gestation, we measured the fetal renal vascularization and blood flow in healthy fetuses using three-dimensional (3-D) power Doppler sonography and quantitative 3-D power Doppler histogram analysis. This study was undertaken with a prospective, cross-sectional design. In total, 106 healthy singletons with gestational ages between 20 and 40 weeks were included. The 3-D power Doppler sonography and quantitative histogram analyses were used to assess the fetal renal vascularization index (VI), flow index (FI) and vascularization-flow index (VFI) in each case. Our results showed that all the VI, FI and VFI increased significantly with gestational age (GA). Using GA as the independent variable, the linear regression equations for fetal renal VI, FI and VFI were VI = 0.214 x GA - 3.5289 (r = 0.84, n = 106, p < 0.0001); FI = 0.3326 x GA + 35.224 (r = 0.33, n = 106, p < 0.001); and VFI = 0.1047 x GA - 1.8064 (r = 0.82, n = 106, p < 0.0001). Our study indicates that normal fetal renal vasculature and blood flow increase with the advancement of gestational age. In addition to our previous study for fetal renal volume using 3-D sonography, our data in this series may serve as a reference for further studies of fetal renal blood flow in abnormal conditions.

Volumetric assessment of normal fetal lungs using three-dimensional ultrasound

We attempted to construct normal reference centiles of fetal lung volume (LV) for clinical application by using three-dimensional (3-D) ultrasound (US) during normal gestation. A prospective study was performed on 195 healthy fetuses with gestational age (GA) ranging from 20 to 40 weeks for the assessment of fetal LV using a 3-D US volume scanner with a mixture of cross-sectional and serial measurements. Polynomial regression analysis was calculated to find the best-fit model between GA, right lung volume (RLV), left lung volume (LLV) and total lung volume (TLV). In addition, common fetal growth parameters, such as biparietal diameter (BPD), occipitofrontal diameter (OFD), head circumference (HCi), abdominal circumference (ACi), femur length (FL) and estimated fetal weight (EFW) were also measured to demonstrate the correlations between RLV, LLV, TLV and these parameters. Our results showed that RLV, LLV and TLV were highly correlated with GA. Using GA as the independent variable and RLV, LLV and TLV as the dependent variable, the best-fit regression equations were: RLV (mL) = 0.067 GA(2) - 1.2464 GA + 2.7825 (r = 0.95, n = 173, p < 0.0001), LLV (mL) = 0.0573 GA(2) - 1.599 GA + 12.454 (r = 0.95, n = 159, p < 0.0001) and TLV (mL) = 0.1263 GA(2) - 2.982 GA + 17.448 (r = 0.96, n = 152, p < 0.0001). For clinical use, a chart of normal growth centiles of fetal LV in utero was then calculated based on this equation. Furthermore, RLV, LLV and TLV were also highly correlated with the common fetal growth parameters during normal gestation (all p < 0.0001). In conclusion, the 3-D US nomograms of the fetal lung volume established in this study can be utilized as useful references in prenatal detection of fetal pulmonary pathologic status and relevant abnormalities.

Quantification of ovarian Doppler signal in hyperresponders during in vitro fertilization treatment using three-dimensional power Doppler ultrasonography

To test the hypothesis that the increased ovarian sensitivity to gonadotropins observed in women embarking on an in vitro fertilization (IVF) treatment may be due to changes in ovarian stromal blood flow, we undertook this prospective comparative clinical study using three-dimensional (3-D) power Doppler ultrasound (US). The 3-D power Doppler ultrasonographic indexes were used to quantify ovarian stromal blood flow and vascularization in hyperresponders. A total of 58 patients undergoing an IVF cycle were recruited and divided into two groups, a hyperresponder group (n = 23) (peak estradiol > 3000 pg/mL or >/= 15 oocytes retrieved) and normal responders (n = 35), based on their response to a standard down-regulation protocol for controlled ovarian stimulation. During ovarian stimulation, on the day of human chorionic gonadotropin (HCG) administration, patients underwent hormonal (serum E2), ovarian volume and 3-D power Doppler (ovarian stroma flow) evaluation. The serum estradiol levels on the day of HCG administration, the number of oocytes retrieved and the ovarian volume were significantly higher in the hyperresponders than in the normal groups. The vascularization flow index (VFI), flow index (FI), and vascularization index (VI), were significantly higher (p < 0.05) in the hyperresponders (1.18 +/- 0.60, 50.23 +/- 2.81 and 2.27 +/- 1.08, respectively), compared to the women with a normal response (0.63 +/- 0.61, 43.19 +/- 7.81 and 1.25 +/- 1.18, respectively). Our study may help to explain the excessive response during gonadotropin administration in the hyperresponsive women.

Assessment of normal fetal liver blood flow using quantitative three-dimensional power Doppler ultrasound

Fetal liver blood flow is very important for fetal hemodynamics. To assess the development of fetal liver vascularization and blood flow in normal gestation, we measured the fetal liver vascularization and blood flow in normal fetuses using the three-dimensional (3-D) power Doppler ultrasound (US) and quantitative 3-D power Doppler histogram analysis. This study was undertaken with a prospective, cross-sectional design. In total, 196 normal singletons with gestational age between 20 and 40 weeks were included. The 3-D power Doppler US and the quantitative histogram analysis were used to assess the fetal liver vascularization index (VI), flow index (FI), vascularization-flow index (VFI) and mean greyness in each case. Our results showed that all the fetal liver VI, FI and VFI increased significantly with gestational age (GA), whereas, fetal liver mean greyness decreased with GA. Using GA as the independent variable, the linear regression equations for fetal liver VI, FI, VFI and mean greyness were VI = 0.5746 x GA - 5.8264 (r = 0.86, p < 0.0001), FI = 0.3291 x GA + 35.624 (r = 0.35, p < 0.001), VFI = 0.2905 x GA - 3.4871 (r = 0.82, p < 0.0001) and mean greyness = -0.2034 x GA + 42.315 (r = -0.20, p < 0.0001). In addition, fetal liver VI, FI, VFI and nean greyness were all significantly correlated with common fetal growth indexes, such as biparietal diameter, occipitofrontal diameter, head circumference, abdominal circumference, femur length and estimated fetal weight. Our study indicates that normal fetal liver vascularization and blood flow change significantly with the advancement of GA as well as fetal growth indexes. We believe our data may serve as a reference for further studies of fetal liver blood flow in abnormal conditions.

Three-dimensional ultrasound in the assessment of normal fetal thigh volume

Accurate assessment of the fetal organ volumes is very important in the evaluation of fetal well-being and maturation. Previous investigators have pointed out that fetal thigh volume (ThiV) may be a useful predictive factor of intrauterine growth retardation. Yet, 2-D ultrasound (US) is limited in assessing fetal ThiV accurately. With the recent advance of 3-D US, the limitation in assessing fetal ThiV by 2-D US can be overcome. To establish a normal reference chart of fetal ThiV for clinical use, a prospective and cross-sectional study using 3-D US was undertaken to assess the fetal ThiV in normal pregnancy. In total, 204 singleton fetuses ranging between 20 and 40 weeks of gestation and fitting the criteria of normal pregnancies were enrolled in this study. Our results showed that fetal ThiV is highly correlated with the gestational age (GA). Furthermore, using GA as the independent variable and ThiV as the dependent variable, the best-fit regression equation was ThiV (mL) = 35.494 - 4.985 x GA + 0.183 x GA(2) (r = 0.91, n = 204, p < 0.0001). For further clinical use, a chart of normal growth centiles of fetal ThiV was then calculated based on this equation. Furthermore, common indexes of fetal biometry, such as biparietal diameter (BPD), occipitofrontal diameter (OFD), head circumference (HC), abdominal circumference (AC), femur length (FL) and estimated fetal weight (EFW), were all highly correlated with ThiV (all p < 0.0001). In conclusion, our data of fetal ThiV assessed by 3-D US can serve as a useful reference in evaluating fetal growth and nutrition status during normal gestation.

Assessment of placental fractional moving blood volume using quantitative three-dimensional power doppler ultrasound

To test the hypothesis that the placental fractional moving blood volume is different with advancing gestational age (GA), we assessed the vascularization index (VI), flow index (FI), and vascularization-flow index (VFI) of the placenta in normal pregnancy by using three-dimensional (3-D) power Doppler ultrasound (US). We enrolled 100 healthy pregnant women with gestational age between 20 to 40 weeks for this study. Three-dimensional power Doppler ultrasonography was used to assess the VI, FI and VFI in each case. Our results showed that the linear regression equations for VI, FI and VFI, by using GA as the independent variable, were VI = 0.27107 x GA -4.02748 (r = 0.84, p < 0.0001), FI = 0.56115 x GA + 34.28945 (r = 0.49, p < 0.001), and VFI = 0.15663 x GA -2.53810 (r = 0.82, p < 0.0001), respectively. In addition, the VI, FI and VFI values of the placental flow were also positively correlated with the fetal growth indices, namely, biparietal diameter, occipitofrontal diameter, head circumference, abdominal circumference and estimated fetal weight (all p values < 0.001). In conclusion, our study illustrates that the fractional moving blood volume of the placenta is positively correlated with the increment of gestational age and the fetal growth indices. Our data may be used as a reference in the assessment of the placental fractional moving blood volume using the quantitative 3-D power Doppler US.

Assessment of fetal adrenal gland volume using three-dimensional ultrasound

To assess the normal fetal adrenal gland volume during normal gestation, we performed a prospective study on 119 normal fetuses with gestational age ranging from 21 to 40 weeks using a 3-D ultrasound (US) volume scanner with a pure cross-sectional design. Polynomial regression analysis was calculated to find the best-fit model between gestational age (GA) and adrenal gland volume. In addition, estimated fetal weight (EFW) was also measured to demonstrate the correlation between adrenal gland volume and fetal weight. Our results showed that fetal adrenal gland volume is highly correlated with GA. Furthermore, using GA as the independent variable and adrenal gland volume as the dependent variable, the best-fit regression equation was adrenal glands volume (mL) = -0.2683 x GA + 0.0082 x GA(2) + 3.1927 (r = 0.93, n = 119, p < 0.0001). For clinical use, a chart of normal growth centiles of fetal adrenal gland volume in utero was then calculated based on this equation. In addition, fetal adrenal gland volume during normal gestation is also highly correlated with EFW (p < 0.0001). In conclusion, our data of fetal adrenal gland volume assessed by 3-D US can serve as a useful reference in evaluating fetal growth status during gestation.

Assessment of normal fetal upper arm volume by three-dimensional ultrasound

Fetal upper arm volume (UAV) is closely related to fetal growth and nutrition status. In the past, 2-D ultrasound (US) has shown limitations in assessing fetal UAV. With the recent advancement of 3-D US, the limitation in assessing fetal UAV by 2-D US can be overcome. To establish a reference chart of fetal UAV for clinical use, a prospective and cross-sectional study using 3-D US was undertaken to assess the fetal UAV in normal pregnancy. In total, 206 singleton fetuses ranging between 20 and 40 weeks of gestation that fit the criteria of normal pregnancies were enrolled in this study. Our results showed that fetal UAV is highly correlated with the gestational age. Furthermore, using gestational age (GA) as the independent variable and UAV as the dependent variable, the best-fit regression equation was UAV (mL) = 43.546 - 4.530 x GA + 0.133 x GA(2) (r = 0.913, n = 206, p < 0.0001). For further clinical use, a chart of normal growth centiles of fetal UAV in utero was then calculated based on this equation. In conclusion, we believe our data of fetal UAV assessed by 3-D US can serve as a useful reference in evaluating fetal growth and nutrition status during gestation.

Infants thinner at birth exhibit smaller kidneys for their size in late gestation in a sample of fetuses with appropriate growth

Fetal ultrasound measurements were employed to investigate the relationship between weight and ponderal index at birth and kidney size during the second (23 weeks) and third (32 weeks) trimesters of pregnancy in a sample of 25 normally growing fetuses. Kidney volume and kidney volume / fetal weight ratio at 32 weeks are significantly and positively related to both weight and ponderal index at birth, controlling for sex, gestational age at birth, and day of ultrasound measurement. A second-degree polynomial relationship approximates the predictability of kidney volume fetal weight ratio at 23 weeks to that at 32 weeks, demonstrating shifting growth rates in fetal organ and body growth relationships during midgestation. Sex and parental size are suggested as contributing to these patterns. Females have a surge in renal growth between 23 and 32 weeks to catch up to earlier growing males, and maternal weight significantly predicts incremental growth in kidney volume and the kidney volume / fetal weight ratio at 32 weeks of gestation. The observation that fetuses relatively thin at birth have relatively smaller kidneys for their size in late gestation suggests that the influence of maternal weight on birth outcome may act through organ growth.

Ovarian stroma flow intensity decreases by age: a three-dimensional power doppler ultrasonographic study

This was a prospective comparative clinical study to test the hypothesis that the flow intensity of the ovarian stroma decreases in the order of the aging process. A total of 100 consecutive women who came to our outpatient clinic for Pap smear examination were recruited. They were divided into three groups. The premenopause group (58 women) had menstruated within the last 3 months and had normal ovaries (no polycystic ovary or any pathologic cyst or mass), as demonstrated on the baseline ultrasound (US) examination. The perimenopause group (20 women) had last menstruated between 3 and 12 months earlier and had normal ovaries. The postmenopause group (22 women) had had no menstrual cycle within the last 12 months and had normal ovaries. Three-dimensional power Doppler US was applied to quantify the blood flow and vascularization within the stroma of the bilateral ovaries. The results showed that the E2 level decreased in the order of: premenopause (mean +/- SD; 40.88 +/- 40.65 pg/mL), perimenopause (22.00 +/- 13.61 pg/mL), then postmenopause (17.25 +/- 16.40 pg/mL). The vascularization index (VI) (6.95 +/- 8.35; 1.11 +/- 0.93; 0.53 +/- 1.75; respectively), flow index (FI) (15.98 +/- 7.59; 12.00 +/- 3.86; 5.18 +/- 5.31; respectively) and vascularization-flow index (VFI) (1.25 +/- 1.59; 0.18 +/- 0.15; 0.09 +/- 0.32; respectively) all decreased significantly in the order of premenopause, perimenopause, then postmenopause. To the best of our knowledge, this is the first study using 3-D power Doppler sonography that proves that the flow intensity decreases along with the aging process in the ovarian stroma.

Prenatal diagnosis of cleft palate by three-dimensional ultrasound

Prenatal diagnosis of cleft palate is very important to prenatal consultation and management after birth. To examine if three-dimensional (3-D) ultrasound (US) is an accurate diagnostic method for clinical use, we analyzed our experience in detecting cleft palate by 3-D US. From June 1996 to January 2000, 21 fetuses with facial clefts were scanned by 2-D US, as well as by 3-D US. The coronal and oblique planes were reconstructed by 3-D US to detect the cleft palate. In addition, level II US was performed to find any possibly associated anomalies. All the scans were recorded on optic disks for final analysis. In our study, the gestational age when prenatal diagnosis was made by US initially was between 20 and 34 weeks. The accuracy for prenatal diagnosis of cleft lip with or without cleft palate by 3-D US was 100%, which was superior to that by 2-D US (p < 0.05). In addition, we proposed a novel method to evaluate the cleft palate systemically by 3-D US. In conclusion, from our study, fetuses with cleft lip combined with or without cleft palate can be easily differentiated by 3-D US. The reconstruction of coronal and oblique planes by 3-D US is a powerful tool for detecting cleft palate.