Three-dimensional sonographic volume measurement of the fetal cerebellum

Purpose The objective of this longitudinal study was to evaluate the growth of the fetal cerebellum in normal pregnancy by using three-dimensional ultrasound. Methods Three-dimensional sonographic examinations were performed for 13 appropriate-for-gestational-age fetuses. Fetal cerebellar volume was measured every 2 to 3 weeks after 20 weeks of gestational age until delivery. The common multiplanar technique was used to calculate the fetal cerebellar volume. Results A curvilinear relationship was found between gestational age and cerebellar volume (R² = 78.6%, P < 0.0001), and normal ranges of cerebellar volume measurements for estimating the growth of the fetal cerebellum during normal pregnancy were generated. The data gathered in this study were fairly comparable with previous data obtained using three-dimensional ultrasound. However, the normal ranges of cerebellar volume that we determined were relatively wide throughout pregnancy. Conclusions Our findings suggest that a standard curve for fetal cerebellar volume using three-dimensional ultrasound can play a role in the evaluation of normal cerebellar growth in the fetus. However, we do cast doubt on the reliability and reproducibility of cerebellar volume measurement using three-dimensional ultrasound. Further studies involving a larger sample size and another technique (the rotational method with VOCAL) would be needed to confirm these findings.     

Three-dimensional sonographic volume measurement of the fetal stomach

The objective of this study was to measure the fetal gastric volume using three-dimensional (3-D) ultrasound during pregnancy. Three-dimensional sonographic examinations were performed involving 35 pregnant women from 12 to 38 weeks of gestation. The fetal gastric volume was monitored every 5 min for a minimum of 40 min (40-60 min) in each woman. The rotational technique with Virtual Organ Computer-aided AnaLysis (VOCAL) was used to calculate the fetal gastric volume. Maximum and minimum gastric volumes were curvilinearly associated with the gestational age, respectively (R(2) = 0.611, p < 0.0001, and R(2) = 0.407, p < 0.0001, respectively). A curvilinear relationship was noted between the functional capacity (maximum volume - minimum volume) of the fetal stomach and gestational age (R(2) = 0.531, p < 0.0001). The maximum volume change [(maximum volume - minimum volume/maximum volume) × 100] did not change during pregnancy (mean and standard deviation, 64.1% ± 16.1%). However, gastric emptying cycles could not be determined in this study because of the short observation period and small number of subjects. Our findings suggest that the fetal gastric volume calculated by conventional two-dimensional ultrasound in previous investigations is approximately one-third of the maximum volume using 3-D ultrasound in the present study and that 3-D ultrasound is a superior means of evaluating the fetal gastric volume in utero. However, the data and their interpretation in the present study should be viewed with some degree of caution because of the small number of subjects. Further studies involving a larger sample size are needed to confirm these findings.     

Three-dimensional sonographic measurement of liver volume in the small-for-gestational-age fetus.

OBJECTIVE: To assess the growth of the fetal liver in normal pregnancies and to evaluate the ability of fetal liver volume measurement for prediction of small-for-gestational-age fetuses. METHODS: Three-dimensional sonographic examinations were performed on 14 appropriate-for-gestational-age and 10 small-for-gestational-age fetuses. Liver volume and liver length were measured every 2 weeks after 20 weeks' menstrual age until delivery. RESULTS: A curvilinear relationship was found between the menstrual age and liver volume (R2 = 88.4%; P < .0001), and a normal range of liver volume measurement for estimating the growth of the fetal liver during normal pregnancy was generated. Liver length was normal in 7 of 10 small-for-gestational-age fetuses, whereas liver volume values in all small-for-gestational-age fetuses were below normal ranges in the mid to late third trimester. CONCLUSIONS: Our findings suggest that liver volume may be a useful measurement for diagnosing small-for-gestational-age fetuses in the mid to late third trimester but that liver length may not be predictive. Further studies involving a larger sample size would be needed to confirm this suggestion.     

Prenatal sonographic features of fetal mediastinal teratoma

Mediastinal teratoma can cause severe hydrops fetalis, which worsens the effects of the mass compression on the vital mediastinal organs. A careful sonographic examination is mandatory to demonstrate the characteristic features suggestive of this congenital tumor. We describe these features at 20 weeks gestation. The most prominent finding was the heterogeneous echogenicity of a large cystic-solid mass with hyperechoic dots, seen as a part of the anterior mediastinum immediately posterior to the sternum. Additional diagnostic features included posterior displacement of the heart, low cardiac output, and hypoplasia of the normally structured heart and lungs due to the direct mass compression. These sonographic findings were confirmed at autopsy which confirmed a nonmetastatic immature teratoma. Sonography may enable accurate diagnosis of mediastinal teratoma considering the anterior location and heterogeneous appearance of the mass, posterior displacement of the heart, normal lung morphology, and compression effects on these organs.     

Three-dimensional ultrasound: Display modalities in obstetrics

Three-dimensional ultrasound (3DUS) has recently been introduced into clinical practice. Various techniques are available for display of the volume data. We review the importance of selecting the proper display option and rendering mode depending on the specific diagnostic question. Current display options include (1) arbitrary planar images similar to conventional two-dimensional US images, (2) surface rendering with emphasis on soft tissues or skeletal detail, (3) stereo viewing using liquid crystal glasses or red/blue glasses, and (4) cine review of gated studies. Rotation of volume data also is important in understanding/comprehending patient anatomy. The range of rotation angles varies depending on the clinical setting. Also data storage requirements increase as the number of views increases. © 1997 John Wiley & Sons, Inc. J Clin Ultrasound 25:157–167, 1997     

Three-dimensional ultrasonic volume measurement of the ovary in women with polycystic ovary syndrome

Objective To explore the ability of 3D volume measurement to evaluate the ovaries of normal women and women with polycystic ovary syndrome (PCOS). Methods 3D images of the ovaries of 10 patients with polycystic ovary syndrome (PCOS) and 10 normal women with regular menstrual cycles were reconstructed. Three-dimensional ultrasonography was used to calculate ovarian volume, stromal volume, and follicular number in each patient. A Voluson 530D ultrasound system (Medison) with software version 4 was used to obtain the images. The trapezoid formula was used to measure ovary and follicle volume by outlining the areas of multiple parallel sections at different distances from the ovary and follicle. Stromal volume was determined by subtracting the sum volume of the follicles from ovarian volume. Results Ovarian volume in normal and PCOS women was 5.66±2.30 cm³ and 9.41±3.08 cm³, respectively (P=0.0002); stromal volume was 4.54±1.83 cm³ and 8.31±3.07 cm³, respectively (P=0.0005); and follicular number was 3.55±1.57 and 11.25±4.33, respectively (P=0.0001). Stromal volume and follicular number correlated closely with ovarian volume in PCOS patients (r²=0.944,P=0.0001 and r²=0.486,P=0.006, respectively). Conclusion Accurate volume measurement with 3D ultrasound allows quantitative evaluation of the ovary. The excellent reconstructive images and convenient volume measurement of 3D ultrasound support its use in obstetrics and gynecology.     

Three-dimensional sonographic features of a fetus with Wolf-Hirschhorn syndrome

We present a case of fetal Wolf-Hirschhorn syndrome diagnosed by conventional two-dimensional and three-dimensional ultrasonography. Conventional two-dimensional ultrasonography revealed a diaphragmatic hernia, nuchal edema, and suspected hypospadias. Three-dimensional ultrasonography clearly showed a flattening of the face, a high forehead, a broad nasal bridge continuing to the forehead, exophthalmos, and micrognathia (resembling the appearance of a Greek warrior helmet), but conventional two-dimensional ultrasonography did not depict these findings. Prenatal chromosomal analysis confirmed the diagnosis of Wolf-Hirschhorn syndrome [46XY, del(4)(p15.2)]. Here we demonstrate how three-dimensional ultrasonography provided a novel visual depiction of the facial dysmorphism, which helped substantially in prenatal counseling.     

三维超声测量胎儿肾脏及其血流容积与孕龄的相关性研究

目的探讨三维超声测量胎儿肾脏体积及肾脏血流容积与孕龄相关关系。方法应用三维超声重建技术测量89例(150枚肾脏)正常胎儿肾脏体积(Vr)及肾脏血流容积(Vf)并计算其比值(Vi)。结果①胎儿肾脏体积(Vr)与孕龄呈正相关(r=0.895,P<0.01);②胎儿肾脏血流容积(Vf)与孕龄呈正相关(r=0.752,P<0.01);③胎儿肾脏体积(Vr)及肾脏血流容积(Vf)的比值(Vi)与孕龄无明显相关性。结论三维超声可较准确测量胎儿肾脏及其血流容积,二者与孕龄呈线性正相关。     

Correlation between fetal gastric size and amniotic fluid volume

PURPOSE: Since abnormal conditions of the fetal digestive tract may alter both amniotic fluid volume and fetal gastric volume, we sought to determine whether amniotic fluid volume is correlated with fetal gastric volume in normal pregnancy. METHODS: A total of 280 fetal gastric size measurements were made prospectively from routine sonographic examinations of women with normal singleton pregnancies between 16 and 42 weeks of gestation. The fetal stomach was defined as the largest area including the pyloric site on transverse or oblique real-time sonographic scans. Gastric volume was calculated according to the formula for a prolate ellipsoid. The amniotic fluid index (AFI) was used for the evaluation of amniotic fluid volume. RESULTS: Both fetal gastric volume and AFI were significantly correlated with gestational age (R2= 0.422 and R2= 0.128, respectively). Only a weak correlation was found between gastric volume and AFI (R2= 0.036, p <0.001). On multivariate linear regression analysis adjusting for gestational age and fetal biometric measurements, gastric volume was not an independent and significant predictor of AFI. CONCLUSIONS: Although sonographically determined fetal gastric volume measurements appear to be useful in the assessment of fetal digestive tract anomalies, fetal gastric volume has no clinically significant effect on the amniotic fluid volume in normal pregnancy.     

Reproducibility of 3-dimensional sonographic measurements of fetal and placental volume at gestational ages of 11-18 weeks

PURPOSE: Determine the reproducibility of 3D ultrasound (3DUS) measurements of fetal and placental volumes. METHODS: We included 34 pregnant women between gestational weeks (GW) 11-18. Two operators independently acquired fetal and placental volumes using 3DUS. Each volume was acquired twice and stored on disk for off-line analysis. Intra- and interobserver reproducibility was expressed in the intra- and interclass correlation coefficient (intra-CC and inter-CC). In addition, the 3DUS volumes acquired by the first operator were calculated by the second and vice-versa to evaluate the effect of volume acquisition and caliper placement. A value >0.75 was considered a good agreement. RESULTS: Fetal and placental volume measurements were successful in 97% of all cases. Between GW 11-14 and 14-18 the median fetal volume was 20.8 (5.0-35.1) and 51.7 (37.9-132.8) ml, the median placental volume was 71.3 (40.9-111.9) and 120.7 (94.2- 273.7) ml. Bland-Altman plots were used for statistical analysis. The intraobserver reproducibility was good for fetus (intra-CC: 0.99; 0.99) and placenta (intra-CC: 0.99; 0.98). Also, interobserver reproducibility was good for fetus (inter-CC 0.98) and placenta (inter-CC 0.98). In addition, regardless of the operator who acquired the volumes, the inter-CC remained good for both fetus (inter-CC: 0.99; 0.99) and placenta (inter-CC: 0.97; 0.99). CONCLUSION: The reproducibility of fetal and placental volume measurements by 3DUS between GW 11-18 is good. In addition, individually chosen caliper placement and volume acquisition has no effect on the calculation of either volumes.     

三维超声测量胎儿肺体积及其在常见胎儿肺病变随访中的应用

目的利用三维超声技术测量胎儿肺体积,建立肺体积正常值范围,评价胎儿肺发育。方法选择显示满意的300胎18～36周正常胎儿肺三维容积图像,利用VOCAL技术测量其左、右肺体积,并对肺总体积(TLV)与孕周(GA)进行回归分析。随机抽取20胎正常胎儿TLV测值进行可信度分析。对4胎超声诊断为肺囊性腺瘤样畸形或隔离肺胎儿进行随访,测量其TLV,与正常胎儿TLV行散点图比较,观察其变化趋势。结果胎儿肺三维图像满意者占91.74%(300/327)。正常胎儿TLV随GA增加而增大,最适回归方程为:TLV=1.139-1.418GA+0.093GA2(r=0.99,P<0.01)。三维超声测量胎儿TLV的可信度很高(内部一致性系数为0.99,组内相关系数为0.99)。4胎肺病变胎儿TLV均随GA增加而增大,但变化趋势各不相同。结论三维超声能够很好地测量胎儿肺体积,在评价胎儿肺发育中具有重要作用。     

MRI定量评估胎儿脑体积

目的观察MRI定量脑体积评估胎儿大脑发育的价值。方法对60例排除胎儿中枢神经系统异常或发育不良、孕周(GA)21～37周的单胎妊娠孕妇行胎儿MR检查,采用单次激发快速自旋回波(SSTSE)序列采集胎儿MRI,经后处理后手动分割大脑,测量胎儿三维脑体积指标颅腔内体积(ICV)、脑总容积(TBV)和脑脊液容积(CFV),计算大脑二维径线指标,包括大脑双顶径(BPD)、骨性双顶径(SBD)、枕额径(SOD)及头围(HC)。分析二维径线指标及三维脑体积指标与GA的相关性,并进行回归分析;观察三维脑体积指标与二维径线指标间的关系。结果 TBV(r=0.98)、ICV(r=0.97)、CFV(r=0.89)、BPD(r=0.96)、SBD(r=0.94)、SOD(r=0.96)、HC(r=0.96)均与GA呈高度正相关(P均<0.01)。TBV及ICV与二维径线各指标间均高度正相关(P均<0.01),HC与CFV间亦呈高度相关(P<0.01)。结论 MRI三维定量脑体积可较好评估GA 21～37周胎儿颅脑生长发育,有望为产前诊断胎儿脑疾病及研究其发病机制提供新的影像学手段。     

Application of lung volume measurement by three-dimensional ultrasonography for clinical assessment of fetal lung development.

OBJECTIVE: To prepare nomograms for normal fetal lung volume using three-dimensional ultrasonography and to evaluate the possibility of clinical applications of this procedure. METHODS: One hundred twenty-five healthy neonates with birth weights within +/-1.5 SD (group A), 9 neonates with intrauterine growth restriction (birth weight less than -1.5 SD) but no severe respiratory disturbance at birth (group B), and 10 neonates with severe respiratory disturbance but no intrauterine growth restriction (group C) were studied. With the use of a three-dimensional ultrasonographic device, continuous B-mode images centering on the fetal thorax were acquired as volume data. Analytical software was used to repeatedly trace the contours of bilateral fetal lungs on transverse slices to calculate the lung volume. RESULTS: In group A, the total volume of normal fetal lungs can be expressed by the second-degree regression equation: 0.08 x (gestational week - 30.1)2 + 3.28 x gestational week - 67.2 (R = 0.909; P < .001). The lung volumes of groups B and C were below the 25th and 2.5th percentiles, respectively, of this regression curve. For the same case, the lung volume increased with gestational week in group B but remained unchanged or even decreased in group C. The total volume of normal fetal lungs can also be expressed by the linear regression equation: 0.02 x estimated fetal weight + 0.29 (R = 0.902). The lung volumes of groups B and C were distributed below and above, respectively, the 2.5th percentile of the regression line. CONCLUSIONS: This analytical method may be applied to evaluate lung development.     

Three-dimensional volume sonographic study of fetal anatomy: intraobserver reproducibility and effect of examiner experience.

OBJECTIVE: The purpose of this study was to evaluate the accuracy of 3-dimensional (3D) sonography in assessing fetal anatomy and to determine the intraobserver reproducibility and the effect of examiner experience. METHODS: Three-dimensional volumes of the head, face, thorax, and abdomen were obtained for 40 fetuses. The volume data sets obtained were explored offline with multiplanar navigation and tomographic ultrasound imaging on a personal computer. Each case was examined twice by the same observer at least 3 months apart. The percentage for identification of fetal anatomic structures, 2-dimensional (2D) and 3D measurements, and the time spent on 2D and 3D examinations were calculated and compared. RESULTS: Ninety-two percent of fetal anatomic structures were identified with multiplanar navigation and tomographic ultrasound imaging. The genitals, the entry of the vena cava, and the ears were visualized in less than 70% of cases. Tomographic ultrasound imaging allowed viewing of 14 structures not seen in the multiplanar study. Intraobserver agreement for anatomic examinations was good (kappa = 0.78). Intraobserver agreement for fetal measurements showed differences between both examinations that approached 0 and intraclass correlation indices close to 0.9. The mean 2D scanning time +/- SD was 10.11 +/- 2.5 minutes, and the acquisition time for the 3D volumes was 1.54 +/- 0.35 minutes. The total time for the second 3D study was 7.23 +/- 1.17 minutes, significantly shorter than the 9.96 +/- 1.53 minutes spent on the first study (P < .001). CONCLUSIONS: Three-dimensional volumes are highly effective for complete fetal anatomic surveys. They show excellent intraobserver reproducibility and take less time to study as the examiner's experience increases.     

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.     

超声诊断胎儿多囊性肾发育不良的价值

目的 分析胎儿多囊性肾发育不良的超声和病理特征,以提高超声对其诊断率.方法 9例胎儿多囊性肾发育不良,共11个肾,分析其声像图特征;引产7例,并对引产胎儿进行泌尿系解剖病理分析.结果 9例胎儿多囊性肾发育不良表现为肾脏形态失常,多发大小不等囊肿;病理标本显示肾脏多发大小不等囊肿,肾蒂及集合系统发育不良.结论 胎儿多囊性...