Multiethnic growth standards for fetal body composition and organ volumes derived from 3D ultrasonography.

BACKGROUND: A major goal of contemporary obstetrical practice is to optimize fetal growth and development throughout pregnancy. To date, fetal growth during prenatal care is assessed by performing ultrasonographic measurement of 2-dimensional fetal biometry to calculate an estimated fetal weight. Our group previously established 2-dimensional fetal growth standards using sonographic data from a large cohort with multiple sonograms. A separate objective of that investigation involved the collection of fetal volumes from the same cohort. OBJECTIVE: The Fetal 3D Study was designed to establish standards for fetal soft tissue and organ volume measurements by 3-dimensional ultrasonography and compare growth trajectories with conventional 2-dimensional measures where applicable. STUDY DESIGN: The National Institute of Child Health and Human Development Fetal 3D Study included research-quality images of singletons collected in a prospective, racially and ethnically diverse, low-risk cohort of pregnant individuals at 12 U.S. sites, with up to 5 scans per fetus (N=1730 fetuses). Abdominal subcutaneous tissue thickness was measured from 2-dimensional images and fetal limb soft tissue parameters extracted from 3-dimensional multiplanar views. Cerebellar, lung, liver, and kidney volumes were measured using virtual organ computer aided analysis. Fractional arm and thigh total volumes, and fractional lean limb volumes were measured, with fractional limb fat volume calculated by subtracting lean from total. For each measure, weighted curves (fifth, 50th, 95th percentiles) were derived from 15 to 41 weeks' using linear mixed models for repeated measures with cubic splines. RESULTS: Subcutaneous thickness of the abdomen, arm, and thigh increased linearly, with slight acceleration around 27 to 29 weeks. Fractional volumes of the arm, thigh, and lean limb volumes increased along a quadratic curvature, with acceleration around 29 to 30 weeks. In contrast, growth patterns for 2-dimensional humerus and femur lengths demonstrated a logarithmic shape, with fastest growth in the second trimester. The mid-arm area curve was similar in shape to fractional arm volume, with an acceleration around 30 weeks, whereas the curve for the lean arm area was more gradual. The abdominal area curve was similar to the mid-arm area curve with an acceleration around 29 weeks. The mid-thigh and lean area curves differed from the arm areas by exhibiting a deceleration at 39 weeks. The growth curves for the mid-arm and thigh circumferences were more linear. Cerebellar 2-dimensional diameter increased linearly, whereas cerebellar 3-dimensional volume growth gradually accelerated until 32 weeks followed by a more linear growth. Lung, kidney, and liver volumes all demonstrated gradual early growth followed by a linear acceleration beginning at 25 weeks for lungs, 26 to 27 weeks for kidneys, and 29 weeks for liver. CONCLUSION: Growth patterns and timing of maximal growth for 3-dimensional lean and fat measures, limb and organ volumes differed from patterns revealed by traditional 2-dimensional growth measures, suggesting these parameters reflect unique facets of fetal growth. Growth in these three-dimensional measures may be altered by genetic, nutritional, metabolic, or environmental influences and pregnancy complications, in ways not identifiable using corresponding 2-dimensional measures. Further investigation into the relationships of these 3-dimensional standards to abnormal fetal growth, adverse perinatal outcomes, and health status in postnatal life is warranted.

3-D transesophageal echocardiography aids in assessment of embolic stroke due to aortic atherosclerotic plaque: A case series.

Atherosclerosis is the most common cause of heart disease and stroke. Plaque thickness ≥4 mm in the ascending aorta or aortic arch is strongly correlated with cerebral embolic events and ischemic stroke. However, despite imaging workup, the cause of embolic stroke remains unidentified in many patients. Transesophageal echocardiography (TEE) is the preferred echocardiographic method for the evaluation of cardiac source of emboli. 2D TEE imaging evaluates aortic root and aortic arch in a single plane or two planes with biplane imaging. However, 2D TEE often fails to detect mobile or complex components in the ascending aorta and aortic arch plaques. The routine availability of 3D TEE in current ultrasound systems may significantly improve the assessment of aortic plaques as a potential embolic source. In this case series, we present four consecutive patients with stroke who underwent TEE by a single cardiologist for possible cardioembolic source. Some of these patients may have been labelled as "cryptogenic stroke" or "embolic stroke of undetermined source" (ESUS) due to the presence of insignificant or nonmobile ascending aortic or aortic arch plaques on 2D TEE imaging. In our four consecutive patients with ESUS who underwent TEE by a single operator, 3D TEE showed complex aortic arch plaques with ulceration with mobile components and established these plaques as the likely source of embolic stroke.

Reference ranges of fetal cisterna magna volume measurements by three-dimensional ultrasonography in the late second trimester considering sonographic experience.

BACKGROUND: Volume measurements of fetal cisterna magna (CM) by three-dimensional (3D) ultrasonography may have a role in the diagnosis of various posterior fossa abnormalities. PURPOSE: To evaluate reference intervals and reliability of fetal CM volume values by virtual organ computer-aided analysis (VOCAL) in structurally normal fetuses, considering experience of evaluators. MATERIAL AND METHODS: Three operators with different 3D sonography experience levels measured CM volumes of 100 structurally normal fetuses at 18-27 weeks of gestation. Reference intervals for CM volumes were generated. Intraclass correlation coefficients (ICC) were calculated. RESULTS: Mean fetal CM volume measurements by the three operators did not significantly (P = 0.49, P = 0.22, and P = 0.17, respectively) change through 20-23 weeks of gestation. Moderate degrees of inter-observer reliability were found with an ICC of 0.69 between novice and intermediate-level, ICC of 0.74 between experienced and intermediate-level, and ICC of 0.78 between experienced and novice observer, respectively. The novice sonographer generally overestimated CM measurements. Intra-observer reliability was good (ICC=0.85). CONCLUSION: A reference chart for fetal CM volume by VOCAL was formed, revealing uniform mean values of 20-23 weeks of gestation. The inter-observer reliability is moderate, and biases seem relatively common for all experience categories.

Three-Dimensional Coronal Plane of the Uterus: A Critical View for Diagnostic Accuracy.

Two-dimensional transvaginal and transabdominal ultrasound (US) examinations are the suggested methods for examining the uterus. Three-dimensional (3D) US, which is not compulsory by society guidelines, provides additional uterine views, reassuring users of pathologic conditions not evident on customary sagittal and transverse views. The 3D coronal plane is rarely seen by 2-dimensional US transducers, let alone in extremely retroverted or axial uteri. Ultrasound machines nowadays feature 3D US capability. Our experience is that the coronal uterine view is a problem solver, helping diagnostic abilities of pelvic imaging. We advocate its liberal use and its acquisition in every pelvic scan. In this Pictorial Essay we present examples to demonstrate its use.

Fetal Weight Estimation Using Automated Fractional Limb Volume With 2-Dimensional Size Parameters in Diabetic Pregnancies.

OBJECTIVES: To examine the effect of adding automated fetal fractional limb volume (FLV) with conventional 2-dimensional (2D) fetal weight estimation procedures in a cohort of diabetic pregnancies. METHODS: A pilot study of diabetic pregnancies measured standard fetal biometry within 7 days of delivery. Fractional arm volume (AVol) and fractional thigh volume (TVol) soft tissue parameters were measured with a commercially available automated software utility (5D Limb Vol; Samsung Medison Co, Ltd, Seoul, Korea). Three conventional weight prediction models that included only 2D size parameters were compared to FLV models that included AVol or TVol. Estimated and actual birth weight (BW) were assessed for the mean percent difference ± standard deviation of the percent differences. Systematic errors were evaluated by the Student t test, and random errors were compared by the Pitman test for correlated variances. The proportion of neonates with estimated fetal weight within 10% of BW was compared between groups by the McNemar test. RESULTS: Ninety gravid women were enrolled with pregestational (26.7%) or gestational (73.3%) diabetes. All prediction models were accurate, with the exception of small underestimations by the model of Schild et al (-3.8%; Ultrasound Obstet Gynecol 2004; 23:30-35). Random errors for the AVol (6.2%) and TVol (6.9%) models were significantly more precise than the other 3 prediction models: Hadlock et al (7.8%; Am J Obstet Gynecol 1985; 151:333-337), INTERGROWTH-21st (8.0%; Ultrasound Obstet Gynecol 2017; 49:478-486), and Schild et al (8.6%; P < .01). The greatest proportion of cases with BW ±10% was also classified by the AVol (91.1%) and TVol (91.1%) models, followed by Hadlock (83.3%), INTERGROWTH-21st (78.9%), and Schild (76.7%) predictions. CONCLUSIONS: The addition of automated FLV measurements to conventional 2D biometry was associated with improved weight predictions in this cohort of diabetic pregnancies.

Fetal Weight Estimation Using Automated Fractional Limb Volume With 2-Dimensional Size Parameters: A Multicenter Study.

OBJECTIVES: To develop new fetal weight prediction models using automated fractional limb volume (FLV). METHODS: A prospective multicenter study measured fetal biometry within 4 to 7 days of delivery. Three-dimensional data acquisition included the automated FLV that was based on 50% of the humerus diaphysis (fractional arm volume [AVol]) or 50% of the femur diaphysis (fractional thigh volume [TVol]) length. A regression analysis provided population sample-specific coefficients to develop 4 weight estimation models. Estimated and actual birth weights (BWs) were compared for the mean percent difference ± standard deviation of the percent differences. Systematic errors were analyzed by the Student t test, and random errors were compared by the Pitman test. RESULTS: A total of 328 pregnancies were scanned before delivery (BW range, 825-5470 g). Only 71.3% to 72.6% of weight estimations were within 10% of actual BW using original published models by Hadlock et al (Am J Obstet Gynecol 1985; 151:333-337) and INTERGROWTH-21st (Ultrasound Obstet Gynecol 2017; 49:478-486). All predictions were accurate by using sample-specific model coefficients to minimize bias in making these comparisons (Hadlock, 0.4% ± 8.7%; INTERGROWTH-21st, 0.5% ± 10.0%; AVol, 0.3% ± 7.4%; and TVol, 0.3% ± 8.0%). Both AVol- and TVol-based models improved the percentage of correctly classified BW ±10% in 83.2% and 83.9% of cases, respectively, compared to the INTERGROWTH-21st model (73.8%; P < .01). For BW of less than 2500 g, all models slightly overestimated BW (+2.0% to +3.1%). For BW of greater than 4000 g, AVol (-2.4% ± 6.5%) and TVol (-2.3% ± 6.9%) models) had weight predictions with small systematic errors that were not different from zero (P > .05). For these larger fetuses, both AVol and TVol models correctly classified BW (±10%) in 83.3% and 87.5% of cases compared to the others (Hadlock, 79.2%; INTERGROWTH-21st, 70.8%) although these differences did not reach statistical significance. CONCLUSIONS: In this cohort, the inclusion of automated FLV measurements with conventional 2-dimensional biometry was generally associated with improved weight predictions.

Evaluation of Scoliosis With a Commercially Available Ultrasound System.

OBJECTIVES: Currently, radiography with measurement of the Cobb angle is still considered the reference standard for diagnosing scoliosis. However, the ionizing radiation hazard is drawing wide attention. Can 3-dimensional (3D) ultrasound (US) be an alternative modality for diagnosing and monitoring patients with scoliosis? The aim of our study was to assess the reliability and validity of 3D US imaging in the evaluation of scoliosis. METHODS: A commercially available ultrasound system with a magnetic tracking system was selected for long-distance 3D US imaging. Straight phantoms and curved phantoms were scanned with the imaging system to evaluate the stability of the system for curvature measurements. Eight healthy adult volunteers and 28 patients with scoliosis were recruited for long-distance 3D US imaging. The intraclass correlation coefficient was used to test the reproducibility of the interobserver and intraobserver measurements for both the healthy adults and patients with scoliosis. A linear regression analysis and Bland-Altman plot were used to analyze the correlation and to determine the extent of agreement between the angles measured on US images and the Cobb angles measured on conventional radiographs. RESULTS: The 28 patients with scoliosis included 10 male and 18 female patients aged 8 to 37 years (mean age ± SD, 17.7 ± 1.4 years; body mass index, <25 kg/m2 ). In the phantom study, there was no statistically significant difference between the angles measured by the 3D US imaging system and those measured by an angle gauge (P > 0.05). In the clinical study, there was very good interobserver and intraobserver reliability (intraclass correlation coefficients, >0.90) for the US imaging system, with a high correlation (r2 = 0.92) and agreement between the US and radiographic methods. CONCLUSIONS: The long-distance 3D US imaging system offers a viable modality for diagnosing and monitoring scoliosis without radiation.

Using 3-dimensional ultrasound islice technology for the diagnosis of developmental dysplasia of the hip.

OBJECTIVES: This study aimed to investigate the reliability of 3-dimensional (3D) ultrasound in screening for developmental dysplasia of the hip (DDH) by comparing the results with those of 2-dimensional (2D) ultrasound. METHODS: One hundred five infants who were younger than 6 months were enrolled in this study. All of the infants underwent 2D and 3D ultrasound scanning for DDH by novices and experts, and the images were graded by a lead expert. The scanning time and image grades were analyzed by Student t tests (P < .05). The consistency of the α angle measurement between the novices and experts was evaluated by the intraclass correlation coefficient (ICC). RESULTS: The 105 infants included 34 boys and 71 girls. On 2D scanning, there was agreement between the experts about the correct diagnosis, whereas in the novice group, 41 infants had misdiagnoses. There were no misdiagnoses with 3D scanning in either group. In the novice group, the mean image grades ± SD were 4.2 ± 1.3 (2D ultrasound) and 8.1 ± 0.7 (3D ultrasound; P < .05). In the expert group, the mean image grades were 7.4 ± 1.0 (2D ultrasound) and 8.2 ± 1.0 (3D ultrasound; P < .05). There was no statistically significant difference between the groups in the grades for 3D ultrasound (P = .83). The scanning time for 3D ultrasound was shorter than that for 2D ultrasound in both groups (P < .05). In the novice group, the ICC of the α angle between the 2D and 3D ultrasound results was 0.34, and in the expert group, it was 0.92. The ICCs were 0.35 and 0.84, respectively when comparing 2D and 3D ultrasound results in the groups. CONCLUSIONS: Three-dimensional ultrasound required less time and showed greater inter-rater reliability than 2D ultrasound for detecting DDH.

Application of Contrast-Enhanced Real-time 3-Dimensional Ultrasound in Solid Abdominal Organ Trauma.

OBJECTIVES: To determine whether real-time 3-dimensional ultrasound (RT3DUS) could provide additional information on early detection and evaluation in the management of solid abdominal organ trauma based on an animal model. METHODS: Nine bleeding lesions were developed in the livers (n = 3), kidneys (n = 3), and spleens (n = 3) from 9 pigs. An ultrasound contrast agent was administered intravenously (liver, 0.025 mL/kg; kidney, 0.008 mL/kg; and spleen, 0.013 mL/kg) after an unenhanced 2-dimensional ultrasound (2DUS) examination (B-mode and color Doppler). After contrast agent injection, bleeding lesions were imaged by 2DUS and sequentially imaged by 3-dimensional static ultrasound (3DSUS) and RT3DUS to identify active bleeding, observe the relationship between bleeding lesions and peripheral blood vessels, and evaluate the spatial scope of the bleeding lesions in the organs. RESULTS: For the identification of active bleeding, there was no statistical difference in contrast-enhanced 2DUS, 3DSUS, and RT3DUS. For observation of the relationship between bleeding lesions and peripheral blood vessels, RT3DUS performed statistically better than 2DUS (P < .05), as reconstructed RT3DUS could show more information about the relationship. For the evaluation of the spatial scope of the bleeding lesion in the organ, RT3DUS also performed statistically better than 2DUS from the multiplanar observation by postprocessing of the 3-dimensional real-time volumes (P < .05). CONCLUSIONS: Real-time 3-dimensional ultrasound improves early detection and evaluation of solid abdominal organ trauma and provides additional information over the current contrast-enhanced 2DUS.

A Pilot Study Comparing 2- and 3-dimensional Ultrasound Imaging for Confirmation of Essure Fallopian Tube Pregnancy Prevention Implants.

STUDY OBJECTIVE: To show the feasibility of 2-dimensional (2D) ultrasound (US) imaging compared with 3-dimensional (3D) US to identify the location of implants and assess if the classification developed by Simorre et al in 2016 was applicable to the 2 types of US imaging (i.e., 2D and 3D). DESIGN: A prospective study (Canadian Task Force classification II-2). SETTING: The department of obstetrics and gynecology in a teaching hospital. PATIENTS: One hundred fifty patients who had undergone hysteroscopic sterilization with Essure (Bayer Pharma AG Laboratory, Lyon, France) fallopian tube pregnancy prevention implants were invited by letter to participate in the study; 50 replied positively between January and August 2017. INTERVENTIONS: An initial 2D US was performed followed by 3D US reconstruction. The primary end point was to compare the identification of device placement with 2D and 3D US imaging procedures according to this new classification. Secondary considerations were to evaluate the difficulty of attaining images, the quality of implant curvature, the duration of each imaging procedure, and the number of images performed for each technique. MEASUREMENTS AND MAIN RESULTS: Ninety-six percent of tubal implants were observed via 3D US compared with 100% via 2D US. The mean time of 2D US was 14.64 seconds for the right fallopian tube and 15.25 seconds for the left fallopian tube compared with 25.11 seconds for the right and 31.57 seconds for the left fallopian tube in 3D US (p <.01). The mean number of image acquisitions per patient was 1.02 (±0.14 standard deviation) for 2D US compared with 1.37 (±0.64 standard deviation) for 3D US (p <.01). The sonographer had no difficulty performing 2D US in 88% of cases compared with 58% of 3D US cases. CONCLUSIONS: Two-dimensional ultrasound appears to be an acceptable alternative to 3D US. We propose a 2D classification for cross section device localization to facilitate image interpretation.

Assessment of the Placental Cord Insertion Using 3-Dimensional Ultrasound at the Time of the Structural Fetal Survey.

OBJECTIVES: The influence of placental morphologic characteristics on pregnancy outcomes is poorly understood. Our objective was to evaluate the relationship of the distance of the placental cord insertion from the placental edge (PCI-D) with associated placental characteristics as well as birth outcomes. METHODS: We performed a retrospective cohort study of nulliparous women with singleton gestations undergoing obstetric ultrasound examinations between 14 and 23 weeks' gestation with a cervical length of greater than 3.0 cm who delivered between 24 and 42 weeks. A 3-dimensional volume of the placenta was evaluated. The PCI-D was obtained with Virtual Organ computer-aided analysis software (GE Healthcare, Milwaukee, WI). Generalized linear regression and generalized additive models were fitted to explore the associations between the PCI-D in relation to demographic and clinical characteristics. RESULTS: A total of 216 pregnancies were included in the analysis. The PCI-D did not correlate with maternal age, gestational age at delivery, mode of delivery, or 5-minute Apgar score. Although not statistically significant, the birth weight z score (P = .09) was associated with a longer PCI-D, and gravidity was associated with a shorter PCI-D (P = .10). A low-lying placenta or placenta previa was associated with a longer PCI-D (P = .03). CONCLUSIONS: The PCI-D is associated with a low placental position in the second trimester. These data are helpful for understanding placental development. The PCI-D may be associated with pregnancy-related factors such as birth weight and multigravidity. More research is required to evaluate the effects of pregnancy-related factors on the PCI-D and the effect of the PCI-D on pregnancy outcomes.

First-Trimester Diagnosis of Agnathia-Otocephaly Complex: A Series of 4 Cases and Review of the Literature.

First-trimester ultrasound findings in 4 fetuses with agnathia-otocephaly complex are described. In addition, information from 3 cases reported in the literature was also reviewed, for a total of 7 cases analyzed. All 7 fetuses presented with agnathia and 6 with ventrocaudal displacement of the ears (melotia/synotia). Four fetuses had holoprosencephaly. In 6 cases, the parents opted for termination of pregnancy. The remaining case resulted in premature delivery at 26 weeks due to severe polyhydramnios and early neonatal death. This report highlights the important role of ultrasound in the identification of agnathia-otocephaly complex in the first trimester of pregnancy.

The Vermian-Crest Angle: A New Method to Assess Fetal Vermis Position within the Posterior Fossa Using 3-Dimensional Multiplanar Sonography.

BACKGROUND: Normal morphometry of the vermis and its relation to the posterior fossa (PF) rule out most major anomalies of the cerebellum. However, accurate categorization of the position and size of the fetal vermis remains a challenge. OBJECTIVE: Our aim was to test a new method to assess the position and size of fetal vermis on 3-dimensional ultrasound (3D-US). METHODS: We measured the vermian-crest angle (VCA) in normal fetuses using multiplanar 3D-US. We also assessed the diameters (superoinferior, anteroposterior, and horizontal) and volume of the vermis. The Spearman rank test and linear and polynomial regression analyses were used for statistical purposes. RESULTS: We included 126 fetuses. Mean ± SD gestational age (GA) was 26.3 ± 4.6 (range 17-35.5) weeks. Mean ± SD superoinferior, anteroposterior, and horizontal diameters were 16.2 ± 4.9, 11.2 ± 3.6, and 5.6 ± 1.6 mm, respectively. Median (range) vermian volume was 0.50 (0.05-2.9) cm3. The VCA was 64.49° ± 11.45. We found no correlation between GA and VCA (r = 0.15; p = 0.13), a linear correlation between GA and vermian diameters, and a quadratic correlation between GA and vermian volume. CONCLUSIONS: We provide a new method to assess vermian position and size within the PF using 3D-US. The combined information may be of value for screening purposes, particularly to differentiate between the various pathological situations encountered within the PF.

Deep Infiltrating Endometriosis: Comparison Between 2-Dimensional Ultrasonography (US), 3-Dimensional US, and Magnetic Resonance Imaging.

OBJECTIVES: To evaluate the diagnostic accuracy of 2-dimensional (2D) and 3-dimensional (3D) transvaginal ultrasonography (US) in comparison with magnetic resonance imaging (MRI) for identification of deep infiltrating endometriosis. METHODS: In this prospective observational study, 159 premenopausal women who underwent surgery for a clinical suspicion of deep infiltrating endometriosis were prospectively enrolled. All women underwent 2DUS, 3DUS, and MRI. The following 3 locations of deep endometriosis were considered: (1) intestinal; (2) other posterior lesions (retrocervical septum, rectovaginal septum, uterosacral ligaments, and vaginal fornix); and (3) anterior. The sensitivity, specificity, positive predictive value, and negative predictive value of 2D and 3D transvaginal US in comparison with MRI were determined. RESULTS: Intestinal deep infiltrating endometriosis was identified by 2DUS in 56 of 66 patients, by 3DUS in 59 of 66, and by MRI in 61 of 66. A receiver operating characteristic curve analysis showed optimal results for 2DUS, 3DUS, and MRI (areas under the curve, 0.86, 0.915, and 0.935, respectively) with a statistically significant difference between 2DUS and MRI (P = .0103), even when the 95% confidence interval showed an overlap. Other posterior deep infiltrating endometriosis was identified by 2DUS in 55 of 75 patients, by 3DUS in 65 of 75, and by MRI in 66 of 75. A receiver operating characteristic curve analysis showed very good results for 2DUS, 3DUS, and MRI (areas under the curve, 0.801, 0.838, and 0.857) with no statistically significant differences. In the 12 women with deep infiltrating endometriosis in the anterior location, the nodules were correctly identified by 2DUS in 3 of 12 patients, by 3DUS in 5 of 12, and by MRI in 6 of 12. CONCLUSIONS: Our results seem to suggest that there is a statistically significant difference between 2DUS and MRI for the intestinal location of deep infiltrating endometriosis, whereas no differences were found among the techniques for the other locations.

Clinical Value of 3-Dimensional Ultrasound in Gynecology.

This report provides examples of using 3-dimensional ultrasound diagnostically in gynecology. The cost efficiency it provides and the wide range of applications it has support the routine use of this ultrasound technology in the practice of gynecology.

Application of 2- and 3-Dimensional Sonography Using the Virtual Organ Computer-Aided Analysis Technique to Measure the Hippocampal Formation and Its Correlation With Corrected Gestational Age in Neonates.

OBJECTIVES: The purpose of this study was to use transcranial 2- and 3-dimensional sonography with the Virtual Organ computer-aided analysis (GE Healthcare, Milwaukee, WI) technique to observe the morphologic characteristics of the hippocampal formation and to analyze its correlation with the corrected gestational age. METHODS: Transcranial sonography was performed from the sagittal plane of the anterior fontanel to the sagittal plane of the posterior horn of the lateral ventricle. The morphologic characteristics of the hippocampal formation in 183 singleton neonates with a corrected gestational age of 32 to 43 weeks were observed. The long diameter, short diameter, area, and perimeter of the hippocampal formation were all quantitatively measured. The volume of the hippocampal formation was measured by 3-dimensional sonography using the Virtual Organ computer-aided analysis technique. The correlation between the corrected gestational age and each parameter was analyzed. RESULTS: The display rate of the hippocampal formation was 100% in the neonates with a typical hippocampus shape. In healthy neonates with a corrected gestational age of 32 to 43 weeks, the long and short diameters, area, perimeter, and volume of the hippocampal formation were all positively correlated with the gestational age. CONCLUSIONS: Transcranial sonography could be used as a conventional approach for evaluation of the development of the hippocampal formation in neonates.

Three-Dimensional Shear Wave Elastography of Skeletal Muscle: Preliminary Study.

OBJECTIVES: Two-dimensional (2D) shear wave elastography (SWE) can measure the elasticity of skeletal muscle, tendons, and ligaments. Three-dimensional (3D) SWE has been used to detect breast cancer but has not been applied to the musculoskeletal system. This study aimed to investigate whether 3D SWE could be used in skeletal muscles in vivo. METHODS: The study enrolled 20 healthy volunteers at Beijing Chaoyang Hospital from August to October 2016. Two-dimensional and 3D SWE scans were used to measure the Young modulus of the flexor carpi radialis in the relaxed state. Longitudinal and transverse scanning was performed. Data were analyzed by a 1-way analysis of variance/least significant difference post hoc test, a paired t test, and Bland-Altman plots. RESULTS: The participants included 10 male and 10 female volunteers with a mean age ± SD of 25 ± 5 years. The Young modulus did not differ between 3D and 2D SWE for the sagittal plane (longitudinal scanning, 34.9 ± 5.7 versus 32.7 ± 5.2 kPa; P = .096) or transverse plane (transverse scanning, 9.1 ± 2.1 versus 9.2 ± 1.6 kPa; P = .877). The Young modulus did not differ between sagittal, transverse, and coronal planes for 3D SWE longitudinal scanning (34.9 ± 5.7, 34.3 ± 5.8, and 34.8 ± 5.9 kPa, respectively; P = .936) or 3D SWE transverse scanning (9.1 ± 2.0, 9.1 ± 2.1, and 8.8 ± 2.1 kPa; P = .838). However, the Young modulus for each individual plane (sagittal, transverse, or coronal) differed significantly between longitudinal and transverse scanning (P < .001). CONCLUSIONS: Both 2D SWE and 3D SWE are suitable techniques for clinical use, depending on the examiner's experience/preference. However, 3D SWE provides a multiplanar/multislice view that better illustrates the spatial characteristics of muscle tissue. Three-dimensional SWE may be a new method for fully visualizing the musculoskeletal system.

Repeatability of Female Midurethral Measurement Using High-Frequency 3-Dimensional Transvaginal Ultrasonography.

OBJECTIVES: Imaging assessment of the female urethra is critical for diagnosis and treatment of urinary incontinence. High-frequency 3-dimensional (3D) transvaginal ultrasonography (TVUS) is a novel technique for evaluating the female urethra. The aim of this study was to test the repeatability of 3D TVUS between examiners without prior experience with TVUS. METHODS: Fifty women underwent 3D TVUS. Two examiners without prior experience analyzed the urethral volumes and measured the urethral parameters. Two-dimensional (2D) parameters included urethral sphincter length and urethral sphincter thickness; 3D parameters included urethral sphincter volume, midurethral complex volume, and inner core volume. One of the examiners repeated the evaluations 1 month later. Subsequently, the measurements were compared. RESULTS: The mean age of the patients ± SD was 34.1 ± 8.1 (range, 23-55) years; the mean height, weight, and body mass index were 160.44 ± 5.12 (range, 150-173) cm, 61.80 ± 13.64 (range, 45-110) kg, and 23.98 ± 4.91 (range, 17.53-39.92) kg/m2 , respectively. The results of our study showed excellent to good intraobserver repeatability (intraclass correlation coefficient [ICC], 0.75-0.87) for the evaluations of all parameters but urethral sphincter length (moderate ICC, 0.53), whereas they showed good to moderate interobserver repeatability (ICC, 0.44-0.77) for all parameters. The repeatability of 3D volumes (ICC, 0.59-0.87) tended to be better than that of 2D parameters (ICC, 0.44-0.76). CONCLUSIONS: The intraobserver and interobserver repeatability of high-frequency 3D TVUS measurements of the female urethra was excellent to moderate between examiners without previous experience. The repeatability of 3D measurements tended to be better than that of 2D parameters.

Association Between Endometrial/Subendometrial Vasculature and Embryo Transfer Outcome: A Meta-analysis and Subgroup Analysis.

OBJECTIVES: To examine the association between endometrial/subendometrial vasculature and in vitro fertilization-embryo transfer (IVF-ET) and frozen embryo transfer (FET) outcomes. METHODS: A meta-analysis of studies using endometrial/subendometrial 3-dimensional ultrasound and power Doppler angiography was performed to examine the vascularization index (VI), flow index (FI), and vascularization-flow index (VFI) in pregnant and nonpregnant women. Ten articles were analyzed, including 895 pregnant women and 882 nonpregnant women. RESULTS: A subgroup analysis of the measuring time showed that the endometrial VI (standardized mean difference [SMD], 0.57; 95% confidence interval [CI], 0.40, 0.74; P < .00001), FI (SMD, 0.56; 95% CI, 0.33, 0.78; P < .00001), and VFI (SMD, 0.45; 95% CI, 0.28, 0.61; P < .00001) measured on the ET day, but not on the human chorionic gonadotropin (hCG) trigger day, were significantly higher in pregnant than nonpregnant women. Additionally, the subendometrial FI was significantly increased in pregnant women on the both hCG day (SMD, 0.68; 95% CI, 0.31, 1.06; P = .004) and ET day (SMD, 0.30; 95% CI, 0.08, 0.52; P = .007). A subgroup analysis of cycle type showed that the endometrial VI (SMD, 0.52; 95% CI, 0.30, 0.74; P < .00001), FI (SMD, 0.44; 95% CI, 0.22, 0.66; P = .0001), and VFI (SMD, 0.45; 95% CI, 0.23, 0.67; P = .03) on the ET day were significantly increased in pregnant women in the FET subgroup. CONCLUSIONS: The subendometrial FI on the hCG day and endometrial VI, FI, and VFI on the ET day are potentially associated with pregnancy occurrence during IVF-ET. The endometrial VI, FI, and VFI could help identify appropriate timing for FET. However, the accuracy of these indices in predicting pregnancy occurrence must be further evaluated in additional large-scale studies.

Spatial Configuration of the Uterine Artery Cervical Segment in 3-Dimensional Reconstruction at 11 to 14 Weeks' Gestation.

Uterine artery blood flow measurement is an important component of preeclampsia screening in the first trimester. Transabdominal measurement of the uterine artery pulsatility index has been reported to have relatively low interobserver reproducibility, mainly because the uterine artery is not sampled in the same place every time. We assessed the uterine artery pathway using 3-dimensional power Doppler reconstruction. We found that the artery always forms a loop at the level of the uterine cervix, with anterior descending and posterior ascending segments. The loop spatial position and the appearance of its segments vary according to the parity. In nullipara, the loop is most times regular, with some variations in orientation. It has an anteroposterior position above or at the level of the internal os, and it represents the most inferior point of the uterine artery at this level. In multipara, the loop is almost always rotated; its segments are tortuous and more elongated. The loop is often not the most inferior point of the uterine artery, and its anterior afferent segment sometimes descends below to the level of the loop. Three-dimensional reconstruction can clearly show the appearance of the uterine artery at the level of the cervix. Understanding the spatial arrangement of the uterine artery could enhance the performance of pulsatility index measurement.