Three-dimensional sonographic measurement of blood volume flow in the umbilical cord

OBJECTIVES

Three-dimensional (3D) umbilical cord blood volume flow measurement with the intention of providing a straightforward, consistent, and accurate method that overcomes the limitations associated with traditional pulsed wave Doppler flow measurement and provides a means by which to recognize and manage at-risk pregnancies.

METHODS

The first study involved 3D sonographic volume flow measurements in 7 healthy ewes whose pregnancies ranged from 18 to 19 weeks' gestation (7 singletons). Sonographic umbilical arterial and venous flow measurements from each fetus were compared to the corresponding average measured arterial/venous flow to assess the feasibility of measurement in a static vessel. A second complementary study involved 3D sonographic volume flow measurements in 7 healthy women whose pregnancies ranged from 17.9 to 36.3 weeks' gestation (6 singletons and 1 twin). Umbilical venous flow measurements were compared to similar flow measurements reported in the literature. Pregnancy outcomes were abstracted from the medical records of the recruited patients.

RESULTS

In the fetal sheep model, arterial/venous flow comparisons yielded errors of 10% or less for 8 of the 9 measurements. In the clinical study, venous flow measurements showed agreement with the literature over a range of gestational ages. Two of the 7 patients in the clinical study had lower flow than anticipated for gestational age; one had a subsequent diagnosis of intrauterine growth restriction, and the other had preeclampsia.

CONCLUSIONS

Accurate measurement of umbilical blood volume flow can be performed with relative ease in both the sheep model and in humans using the proposed 3D sonographic flow measurement technique. Results encourage further development of the method as a means for diagnosis and identification of at-risk pregnancies.

Use of a pressure guidewire in fetal cardiac intervention for critical aortic stenosis

Fetal cardiac intervention for critical aortic stenosis (AS) with evolving hypoplastic left heart syndrome is performed in an attempt to maintain a biventricular circulation postnatally. The procedure has been hindered by technical challenges and poor candidate selection. We report here the novel use of a pressure guidewire during aortic valvuloplasty in a fetus at 21 weeks' gestation with critical AS and evolving hypoplastic left heart syndrome. Use of a pressure guidewire during fetal cardiac intervention offers several potential advantages over existing protocols. This technique augments fetal ultrasound as it relates to operator awareness of catheter and wire position (with continuous monitoring of pressure waveforms), improves on intraprocedural fetal hemodynamic monitoring and responsiveness to resuscitation, and provides a rich new data set of invasive fetal hemodynamics. This data set offers tremendous potential with regards to improving candidate selection and postintervention prognostication. In addition, we provide the first, to our knowledge, characterization of intracardiac pressures in a human fetus with congenital heart disease. Given the realized and potential benefits associated with this technique, use of a pressure guidewire may become standard of care for all fetal cardiac interventions.

Prenatally diagnosed right ventricular outpouchings: a case series and review of the literature

Congenital right ventricular aneurysms and right ventricular diverticula are rare forms of congenital heart disease for which little information exists regarding optimal management, natural history, or prognosis. With advancements in prenatal cardiac evaluation and ultrasound, the reported frequency of these lesions, as well as a better understanding of the natural history of this form of congenital heart disease, is likely to evolve. We present three cases of fetal right ventricular aneurysms/diverticula diagnosed at our institution, along with a review of the current literature. We describe the pre- and postnatal courses as well as suggest counseling and management strategies.

Four-dimensional fetal echocardiography with spatiotemporal image correlation (STIC): A systematic study of standard cardiac views assessed by different observers

OBJECTIVE

To test the agreement between observers and reproducibility of a technique to display standard cardiac views of the left and right ventricular outflow tracts from four-dimensional volume datasets acquired with Spatiotemporal Image Correlation (STIC).

METHODS

A technique was developed to obtain dynamic multiplanar images of the left ventricular outflow tract (LVOT) and right ventricular outflow tract (RVOT) from volume datasets acquired with STIC. Volume datasets were acquired from fetuses with normal cardiac anatomy. Twenty volume datasets of satisfactory quality were pre-selected by one investigator. The data was randomly assigned for a blinded review by two independent observers with previous experience in fetal echocardiography. Only one volume dataset was used for each fetus. After a training session, the observers obtained standardized cardiac views of the LVOT and RVOT, which were scored on a scale of 1 to 5, based on diagnostic value and image quality (1=unacceptable, 2=marginal, 3=acceptable, 4=good, and 5=excellent). Median scores and interquartile range, as well as inter- and intraobserver agreement were calculated for each view.

RESULTS

The mean menstrual age at the time of volume acquisition was 25.5+/-4.5 weeks. Median scores (interquartile range) for LVOT images, obtained by the first and second observers, were 3.5 (2.25-5.00) and 4 (3.00-5.00), respectively. The median scores (interquartile range) for RVOT images obtained by the first and second observers were 3 (3.00-5.00) and 3 (2.00-4.00), respectively. The interobserver intraclass correlation coefficient for the LVOT was 0.693 (95% CI 0.380-0.822), and 0.696 (95% CI 0.382-0.866) for the RVOT. For the intraobserver agreement analysis, observer 1 gave higher scores to the LVOT the second time the volumes were analyzed [LVOT: 3.50 (2.25-5.00) vs. 5.00 (4.00-5.00, p=0.008)].

CONCLUSION

STIC can be reproducibly used to evaluate fetal cardiac outflow tracts by independent examiners. Slightly better image quality rating scores during the intraobserver variability trial suggests the presence of a learning curve for the manipulation and analysis of volume data obtained by STIC.

Gestational age at delivery and Doppler waveforms in very preterm intrauterine growth-restricted fetuses as predictors of perinatal mortality

OBJECTIVE

The aim of this study was to compare gestational age at delivery and the performance of middle cerebral artery (MCA), ductus venosus (DV), and umbilical artery Doppler parameters in the prediction of perinatal mortality and morbidity in intrauterine growth-restricted (IUGR) fetuses delivered at 32 weeks or earlier.

METHODS

The study population consisted of 41 patients with IUGR fetuses. Delivery occurred for maternal or fetal indications. Two-tailed chi(2) and Fisher exact tests, an independent t test, and logistic regression were used for the analysis. P < .05 was considered statistically significant.

RESULTS

Gestational age at delivery ranged between 23.1 and 32 weeks (median, 27.6 weeks). There were 17 perinatal deaths. Ninety-four percent of the perinatal deaths occurred when the fetuses were delivered before 29 weeks. No fetus survived when delivered before 25 weeks. Two parameters predicted the perinatal mortality: gestational age at delivery (odds ratio, 0.52; 95% confidence interval, 0.31-0.88) and the combination of abnormal MCA peak systolic velocity + DV reversed flow (odds ratio, 10.2; 95% confidence interval, 1.8-57). For each week of pregnancy, there was a reduction in perinatal mortality of 48%. No Doppler parameters were significantly associated with perinatal morbidity.

CONCLUSIONS

Gestational age at delivery and the combination of abnormal MCA peak systolic velocity + DV reversed flow in very preterm IUGR fetuses were the best parameters in predicting perinatal mortality. The decreased perinatal mortality that is found for each week IUGR fetuses remain in utero should be taken into account when a decision to deliver an IUGR fetus before 30 weeks is made.

Middle cerebral artery peak systolic velocity: a new Doppler parameter in the assessment of growth-restricted fetuses

OBJECTIVE

The aims of this study were to determine if there is a relationship between middle cerebral artery (MCA) peak systolic velocity (PSV) and perinatal mortality in preterm intrauterine growth-restricted (IUGR) fetuses, to compare the performance of MCA pulsatility index (PI), MCA-PSV and umbilical artery (UA) absent/reversed end-diastolic velocity (ARED) in predicting perinatal mortality, to determine the longitudinal changes that occur in MCA-PI and MCA-PSV in these fetuses, and to test the hypothesis that MCA-PSV can provide additional information on the prognosis of hypoxemic IUGR fetuses.

METHODS

This was a retrospective cross-sectional study of 30 IUGR fetuses (estimated fetal weight < 3(rd) percentile; UA-PI > 95% CI) in which the last MCA-PI, MCA-PSV and UA values were obtained within 8 days before delivery or fetal demise. Among the 30 fetuses, there were 10 in which at least three consecutive measurements were performed before delivery and these were used for a longitudinal study. MCA-PSV and MCA-PI values were plotted against normal reference ranges and were considered abnormal when they were above the MCA-PSV or below the MCA-PI reference ranges.

RESULTS

Gestational age at delivery ranged between 23 + 1 and 32 + 5 (median, 27 + 6) gestational weeks. Birth weight ranged from 282 to 1440 (median, 540) g. There were 11 perinatal deaths. Forward stepwise logistic regression indicated that MCA-PSV was the best parameter in the prediction of perinatal mortality (odds ratio, 14; 95% CI, 1.4-130; P < 0.05) (Nagerlke R(2) = 31). In the 10 fetuses studied longitudinally, an abnormal MCA-PI preceded the appearance of an abnormal MCA-PSV. In these fetuses, the MCA-PSV consistently showed an initial increase in velocity; before demise or the appearance of a non-reassuring test in seven fetuses, there was a decrease in blood velocity. The MCA-PI presented an inconsistent pattern.

CONCLUSIONS

In IUGR fetuses, the trends of the MCA-PI and MCA-PSV provide more clinical information than does one single measurement. A high MCA-PSV predicts perinatal mortality better than does a low MCA-PI. We propose that MCA-PSV might be valuable in the clinical assessment of IUGR fetuses that have abnormal UA Doppler.

Volume change of uterine myomas during pregnancy: do myomas really grow?

STUDY OBJECTIVE

To estimate changes in uterine myoma volume during pregnancy.

DESIGN

Review of departmental electronic perinatal database and medical records. Canadian Task Force Classification II-3.

SETTING

Obstetrical ultrasound unit in an academic tertiary care center.

PATIENTS

One hundred-seven patients diagnosed with uterine myomas during pregnancy and who had two or more obstetrical ultrasounds in different periods of pregnancy.

INTERVENTIONS

We analyzed the change in volume of uterine myomas between the first half of pregnancy (up until 19 weeks), third quarter (20-30 weeks), and last quarter (31 weeks to term). The volume of largest uterine myoma was calculated using the formula Volume (mm3)=Pi/6x(length mm)x(width mm)x(height mm).

MEASUREMENTS AND MAIN RESULTS

The mean age of the population was 31+/-6 years. Between the first and the second study periods, the percentage of uterine myomas that decreased in size was 55.1% (95% CI: 43-66), with a mean decrease in volume of 35%+/-4%; while the percentage of uterine myomas that enlarged was 44.9% (95% CI: 34-56), with a mean increase in volume of 69%+/-11%. Between the second and the third study periods, 75% (95% CI: 56-87) became smaller, with a mean decrease in volume of 30%+/-3%; while 25% (95% CI: 13-43) enlarged, with a mean increase in volume of 102%+/-62%.

CONCLUSION

Contrary to common belief, we found that uterine myomas commonly decrease in volume over the course of pregnancy.

What does 2-dimensional imaging add to 3- and 4-dimensional obstetric ultrasonography?

OBJECTIVE

The purpose of this study was to determine whether 2-dimensional (2D) ultrasonography adds diagnostic information to that provided by the examination of 3-dimensional/4-dimensional (3D/4D) volume data sets alone.

METHODS

Ninety-nine fetuses were examined by 3D/4D volume ultrasonography. Volume data sets were evaluated by a blinded independent examiner who, after establishing an initial diagnostic impression by 3D/4D ultrasonography, performed a 2D ultrasonographic examination. The frequency of agreement and diagnostic accuracy of each modality to detect congenital anomalies were calculated and compared.

RESULTS

Fifty-four fetuses with no abnormalities and 45 fetuses with 82 anomalies diagnosed by 2D ultrasonography were examined. Agreement between 3D/4D and 2D ultrasonography occurred for 90.4% of the findings (123/136; intraclass correlation coefficient, 0.834; 95% confidence interval, 0.774-0.879). Six anomalies were missed by 3D/4D ultrasonography when compared to 2D ultrasonography (ventricular septal defect [n = 2], interrupted inferior vena cava with azygous continuation [n = 1], tetralogy of Fallot [n = 1], horseshoe kidney [n = 1], and cystic adenomatoid malformation [n = 1]). There were 2 discordant diagnoses: transposition of the great arteries diagnosed as a double-outlet right ventricle and pulmonary atresia misinterpreted as tricuspid atresia on 3D/4D ultrasonography. One case of occult spinal dysraphism was suspected on 3D ultrasonography but not confirmed by 2D ultrasonography. When compared to diagnoses performed after delivery (n = 106), the sensitivity and specificity of 3D/4D ultrasonography (92.2% [47/51] and 76.4% [42/55], respectively) and 2D ultrasonography (96.1% [49/51] and 72.7% [40/55]) were not significantly different (P = .233).

CONCLUSIONS

Information provided by 2D ultrasonography is consistent, in most cases, with information provided by the examination of 3D/4D volume data sets alone.

Applications of 2-dimensional matrix array for 3- and 4-dimensional examination of the fetus: a pictorial essay

OBJECTIVES

Two-dimensional (2D) matrix array is a new technology for the performance of 3-dimensional and 4-dimensional (4D) ultrasonography. In this study, we report the use of a 2D matrix array transducer for examination of fetal structures including the fetal heart.

METHODS

Thirty-four fetuses without abnormalities and 19 fetuses with congenital anomalies were examined with a 2D matrix array transducer (x3-1, IE-33; Philips Medical Systems, Bothell, WA). Median gestational age was 25 6/7 weeks (range, 13 0/7-40 1/7 weeks).

RESULTS

(1) A 360 degrees rotation and examination of selected structures was possible in the second trimester. (2) Structures were examined by maintaining the transducer in a fixed position and rotating the volume using the system trackball. (3) Dorsal and ventral parts of the hands and feet were visualized in a single volume data set, in real time, without moving the transducer. (4) Real-time en face visualization of atrioventricular valves was possible from the ventricular or atrial chambers. (5) Four-dimensional images of bones were obtained by decreasing gain settings only, with no need for cropping. (6) Four-dimensional reconstruction of vascular structures was possible with color Doppler imaging. Two limitations were identified: (1) lower resolution than mechanical volumetric transducers, and (2) narrow volume display.

CONCLUSIONS

Real-time direct 4D imaging with 360 degrees rotation for examination of fetal anatomic structures is feasible. This technology allows examination of fetal structures from multiple perspectives, in real time, without the need to move the transducer in the maternal abdomen. Further technological developments may overcome the limitations identified in this study.

Women's responses to ultrasound examinations during routine screens in an obstetric clinic

OBJECTIVE

The primary purpose of this research was to evaluate the impact of prenatal ultrasound consultation on maternal-fetal attachment, knowledge of fetal behavior, and development and reduction of anxiety in pregnant women scheduled for routine ultrasound screens. A standard depression screen was also used to evaluate depression levels of women undergoing these screens in the sonography clinic.

METHODS

To evaluate the impact of an ultrasound consultation, the following were undertaken: (1) a preliminary observational study of routine screens in the sonography clinic was performed; (2) an ultrasound consultation manual was developed and established as reliable; and (3) women undergoing evaluations between 16 and 26 weeks' gestational age were randomly assigned to a standard care group (n = 24; the standard clinical ultrasound screen) or an ultrasound consultation group (n = 28; the ultrasound consultation was done, including the standard screen with extended consultation on fetal development, maternal and familial responses, and maternal-fetal interaction).

RESULTS

The ultrasound consultation group had a significant positive change in maternal-fetal attachment scores, lower state anxiety scores, and more favorable responses to the sonographic examination (P .05). Women's depression scores did not differ between the ultrasound consultation and standard care groups and were similar to maternal prenatal depression levels in other studies.

CONCLUSIONS

Ultrasound consultation was responsible for increasing maternal-fetal attachment and reducing maternal anxiety. It may be an important component of more comprehensive prevention/intervention strategies. The implications for ultrasound consultation in clinical research and practice are discussed.

Three-dimensional ultrasound in the prenatal diagnosis of cleidocranial dysplasia associated with B-cell immunodeficiency

A patient with a singleton pregnancy was referred for three-dimensional ultrasonography (3DUS) at 18 + 3 weeks for suspected hypomineralization of the skull bones and absence of the nasal bones. Three-dimensional rendered images of the fetal skull revealed widening of the coronal sutures, absence of the squamous portion of the temporal bone, and absence of the occipital bone, except for two areas of ossification. In addition, a fractured right clavicle was identified. The remainder of the fetal anatomy was normal and biometry was appropriate for gestational age. Genetic amniocentesis revealed a 46,XX fetal karyotype. Family history was positive for a 5-year-old sibling with an open anterior fontanelle. Cleidocranial dysplasia was suspected. A female neonate was delivered by elective repeat Cesarean section at 40 + 3 weeks of gestation without complications and discharged home 3 days after delivery. Prenatal diagnosis was confirmed by physical and radiological evaluation. The infant died at 8 weeks of age due to respiratory syncytial virus pneumonia secondary to B-cell deficiency. RUNX2 mutations were not detected by molecular analysis. There are three relevant aspects to this case: (1) clear visualization of the widened fontanelles and hypomineralized occipital bones was possible with the use of 3DUS; (2) a clavicular fracture was identified in utero with combined high-resolution two-dimensional and 3DUS; and (3) although absence of the nasal bones is most commonly observed in fetuses with chromosomal disorders (e.g. trisomy 21 and trisomy 18), a careful examination of the skeleton should be considered in fetuses with absent nasal bones and a normal karyotype.

Four-dimensional ultrasonography of the fetal heart using a novel Tomographic Ultrasound Imaging display

OBJECTIVE

The objective of this study was to investigate the feasibility of examining the fetal heart with Tomographic Ultrasound Imaging (TUI) using four-dimensional (4D) volume datasets acquired with spatiotemporal image correlation (STIC).

MATERIAL AND METHODS

One hundred and ninety-five fetuses underwent 4D ultrasonography (US) of the fetal heart with STIC. Volume datasets were acquired with B-mode (n=195) and color Doppler imaging (CDI) (n=168), and were reviewed offline using TUI, a new display modality that automatically slices 3D/4D volume datasets, providing simultaneous visualization of up to eight parallel planes in a single screen. Visualization rates for standard transverse planes used to examine the fetal heart were calculated and compared for volumes acquired with B-mode or CDI. Diagnoses by TUI were compared to postnatal diagnoses.

RESULTS

(1) The four- and five-chamber views and the three-vessel and trachea view were visualized in 97.4% (190/195), 88.2% (172/195), and 79.5% (142/195), respectively, of the volume datasets acquired with B-mode; (2) these views were visualized in 98.2% (165/168), 97.0% (163/168), and 83.6% (145/168), respectively, of the volume datasets acquired with CDI; (3) CDI contributed additional diagnostic information to 12.5% (21/168), 14.2% (24/168) and 10.1% (17/168) of the four- and five-chamber and the three-vessel and trachea views; (4) cardiac anomalies other than isolated ventricular septal defects were identified by TUI in 16 of 195 fetuses (8.2%) and, among these, CDI provided additional diagnostic information in 5 (31.3%); (5) the sensitivity, specificity, positive- and negative-predictive values of TUI to diagnose congenital heart disease in cases where both B-mode and CDI volume datasets were acquired prenatally were 92.9%, 98.8%, 92.9% and 98.8%, respectively.

CONCLUSION

Standard transverse planes commonly used to examine the fetal heart can be automatically displayed with TUI in the majority of fetuses undergoing 4D US with STIC. Due to the retrospective nature of this study, the results should be interpreted with caution and independently confirmed before this methodology is introduced into clinical practice.

Suboptimal second-trimester ultrasonographic visualization of the fetal heart in obese women: should we repeat the examination?

OBJECTIVE

The purpose of this study was to determine whether a repeated antenatal ultrasound examination improves fetal cardiac visualization for the obese and nonobese population.

METHODS

A computerized ultrasound database (October 1999-June 2003) was used to identify singleton pregnancies undergoing repeated prenatal ultrasound examinations because of initial suboptimal ultrasonographic visualization (SUV) of the 4-chamber view, outflow tracts, or both. Women with maternal diabetes, abnormal maternal serum screening results, or known fetal anomalies at the initial examination were excluded. Patients were classified by maternal body mass index (BMI): less than 30 kg/mg2 (nonobese), 30 to 34.9 kg/mg2 (class I obesity), 35 to 39.9 kg/mg2 (class II obesity), and 40 kg/mg2 or greater (morbid obesity). The association between maternal BMI and SUV of the fetal heart was analyzed.

RESULTS

Three hundred seventy-two patients were abstracted from the database. The median gestational age was 19.0 weeks at the initial visit (range, 18.0-21.9 weeks) and 21.4 weeks at the second visit (range, 18.9-23.9 weeks). The median BMI was 32.6 kg/m2 (range, 16.4-58.7 kg/m2). Sixty-three percent of patients were obese (BMI >or=30). Cardiac anatomy continued to have SUV in 11% of the women. The rate of SUV was associated with the obesity class (1.5% for nonobese, 12% for obesity I, 17% for obesity II, and 20% for morbid obesity; P < .0001). A cardiac anomaly was found in 1 of 372 repeated examinations (arteriovenous canal defect) for a patient with BMI of 24.8 kg/m2.

CONCLUSIONS

Repeated ultrasound examination for SUV of the fetal heart at a later gestational age dramatically reduces SUV. However, obese patients continue to have much higher rates of persistent SUV.

The impact of maternal obesity on midtrimester sonographic visualization of fetal cardiac and craniospinal structures

OBJECTIVE

To examine the impact of maternal obesity on the rate of suboptimal ultrasound visualization (SUV) of fetal anatomy and determine the optimal timing of prenatal ultrasound examination for the obese gravida.

METHODS

A computerized ultrasound database was used to identify ultrasound examinations for singleton gestations performed between 14(0/7) and 23(6/7) weeks at a tertiary care, university-based hospital. Patients were divided into four groups and categorized based on body mass index (BMI): nonobese (BMI <30 kg/m2), class I obesity (30< or =BMI<35 kg/m2), class II obesity (35< or =BMI<40 kg/m2), and extreme obesity (BMI > or =40 kg/m2). The rates of SUV for fetal cardiac and craniospinal structures were calculated for each group and compared.

RESULTS

A total of 11,019 pregnancies were studied, of which 38.6% of the patients were obese. Overall, the rate of SUV of the fetal structures was higher for obese compared to nonobese women for both cardiac (37.3 [1723/4200] vs 18.7% [1275/6819]; P<0.0001) and craniospinal structures (42.8 [1798/4200] vs 29.5% [2012/6819]; P<0.0001). Increased severity of maternal obesity was associated with SUV rate for both the cardiac (nonobese 18.7% [1275/6819], class I 29.6% [599/2022], class II 39.0% [472/1123], and extreme obesity 49.3% [580/1055]; P<0.0001) and for the craniospinal structures: (nonobese 29.5% [2012/6819], class I 36.8% [744/2022], class II 43.3% [486/1123], and extreme obesity 53.4% [563/1055]; P<0.0001). With increasing gestational age at examination, the rate of SUV decreased for both obese and nonobese women. However, for obese women there was minimal improvement in visualization after 18-20 weeks. Even after adjustment for gestational age and the type of ultrasound machine, obese women (class I, class II, and extreme obesity) were still associated with increased odds for SUV of the fetal cardiac and craniospinal structures compared to nonobese women.

CONCLUSION

Maternal obesity increases the rate of SUV for the fetal cardiac structures by 49.8% and for the craniospinal structures by 31%. The optimal gestational age for visualization of fetal cardiac and craniospinal anatomy in obese patients may be after 18-20 weeks.

The use of the minimum projection mode in 4-dimensional examination of the fetal heart with spatiotemporal image correlation

OBJECTIVE

The minimum projection mode (MPM) is a rendering algorithm available in some 3- and 4-dimensional ultrasonography systems that, in 1 image, allows the visualization of vessels and cystic anatomic structures located in different scanning planes. The objective of this study was to compare the information displayed in images obtained with the MPM with their corresponding 2-dimensional ultrasonographic images from fetuses with and without structural heart defects.

METHODS

Thirty-two volume data sets acquired with the spatiotemporal image correlation technique from fetuses with (n = 15) and without (n = 17) structural heart defects were analyzed. Rendered images of the upper abdomen, 4-chamber view, and 3-vessel view were compared with the corresponding 2-dimensional images. Two independent observers with experience in fetal echocardiography reviewed these volume data sets using the MPM. The visualization rate of specific anatomic structures seen from a transverse sweep of the heart was recorded for each observer, and the interobserver agreement was assessed by statistical indices of agreement (kappa statistic).

RESULTS

Images obtained by the MPM displayed more vascular structures than those of corresponding 2-dimensional images at the level of the 3-vessel view. For conotruncal anomalies, the minimum mode projected the aorta and pulmonary arteries in 1 single plane, facilitating the understanding of their spatial relationships. The interobserver agreement score was moderate to "almost perfect" for assessment of most anatomic structures in the upper abdomen, 4-chamber view, and 3-vessel view sections. However, interobserver agreement ranged from fair to poor for visualization of the left outflow tract, atrial septum, and flap of the foramen ovale.

CONCLUSIONS

The MPM is an alternative rendering modality that facilitates visualization of normal and abnormal vascular connections to the fetal heart at the level of the 3-vessel view. This technique may be useful in prenatal diagnosis of conotruncal anomalies and in assessment of the spatial relationships of abnormal vascular connections in the upper mediastinum.

Does advanced ultrasound equipment improve the adequacy of ultrasound visualization of fetal cardiac structures in the obese gravid woman?

OBJECTIVE

This study was undertaken to determine the effect of advanced ultrasound equipment on the ability to visualize fetal cardiac structures in obese gravid women.

STUDY DESIGN

Singleton pregnancies undergoing initial ultrasound examination between 14 weeks and 23 weeks 6 days were included. Patients were classified by body mass index (BMI) (nonobese [BMI < 30 kg/m(2)] and obese [BMI > or =30 kg/m(2)]). The rate of suboptimal ultrasound visualization (SUV) of the fetal heart (cardiac axis, cardiac position, 4-chamber, and outflow tracts views) was compared between patients examined by standard (HDI 3000) or advanced ultrasound equipment (HDI 5000) (ATL, Philips Medical Systems, Bothell, Wash).

RESULTS

Over a 5-year period, 7029 singleton gestations met inclusion criteria; 2498 (35.5%) were clinically obese. There was no difference in gestational age, rate of low amniotic fluid volume, anterior placenta, or vertex fetal presentation between the groups. When the advanced ultrasound equipment was used, SUV of the fetal heart was lower in the nonobese population (20.8% vs 16.4%; P <.001), but not in the obese gravid women (38.1% vs 35.5%; P=.27). However, obese patients who were examined by advanced ultrasound equipment after 18 weeks had less SUV of the outflow tracts (28.5% vs 23.1%, P=.04) but not of the 4-chamber view.

CONCLUSION

Despite advanced ultrasound equipment, maternal obesity significantly limits visualization of the fetal heart. However, the advanced ultrasound equipment may somewhat benefit obese gravid women examined after 18 weeks' gestation

Congenital diaphragmatic hernia: associated anomalies and antenatal diagnosis. Outcome-related variables at two Detroit hospitals

This retrospective study reviews the medical records of 77 fetuses and babies with congenital diaphragmatic hernia (CDH) referred to two hospitals in Detroit from 1986 through 2000. The aims were to examine the effects on outcome of multiple variables, especially the type of CDH, associated anomalies, and ultrasound prognostic parameters. Ultrasound measurements of head (HC), chest (CC), and abdominal circumferences (AC) were obtained from videotapes. ANOVA and chi-square analysis were used to determine statistical significance between groups and proportions. Eighty-nine percent (65/73) of pregnancies resulted in live births, and 54% (35/65) of patients survived past 30 days. Liveborn patients with low APGAR scores were less likely to survive. Forty-three percent (30/70) had major associated anomalies, with cardiac anomalies constituting about 52% (33/64) of the major associated anomalies. Seventy percent of patients with isolated CDH survived versus 36% of patients with both CDH and cardiac anomalies. Sixty-seven percent (8/12) of fetuses antenatally diagnosed before 25 weeks of gestation survived past 30 days of birth. The survival rate of right-sided CDH with liver herniation was 80% (8/10), compared with 29% (4/14) for left-sided CDH with liver herniation (p=0.088). There was a significant linear relationship (r=0.603, p =0.029) between CC/AC and CC/HC among patients with CDH; survivors had higher CC/AC and CC/HC values than nonsurvivors. These results support the utility of CC/AC and CC/HC measurements and the presence of liver herniation as important prognostic factors that can be used in antenatal counseling and in planning clinical trials.

Abnormal amniotic fluid volume as a screening test prior to targeted ultrasound

BACKGROUND

The purpose of this study was to examine (1) the association between amniotic fluid volume (AFV) and sonographically detected fetal structural anomalies, and (2) the effectiveness of using abnormal AFV as a screening test prior to patient referral for a targeted ultrasound.

MATERIAL/METHODS

For singleton pregnancies in the 2nd and 3rd trimester frequencies of individual anomalies and odds ratios were calculated for each category of amniotic fluid volume relative to the frequency of anomalies with normal volume. The anomaly detection rate and frequency of referral for targeted ultrasound on the basis of abnormal amniotic fluid volume were calculated.

RESULTS

15,959 (92.0%) of patients had normal amniotic fluid volume, 537 (3.1%) decreased, 544 (3.1%) increased, 167 (1.0%) oligohydramnios, and 141 (0.8%) polyhydramnios. There were 365 (2.1%) fetuses with major structural anomalies. 1.8% of patients with normal AFV had anomalies. Anomalies were significantly more frequent in all categories of abnormal fluid: decreased (3.2%, OR 1.74, 95% CI 1.06-2.86), increased (5.7%, OR 3.22, 95% CI 2.2-4.71), oligohydramnios (9.0%, OR 5.26, 95% CI 3.09-9.05), and polyhydramnios (5.7%, OR 3.21, 95% CI 1.56-6.6). Referral for targeted ultrasound based on any abnormal AFV volume compared to only oligohydramnios or polyhydramnios increased the overall anomaly detection rate by nearly three-fold (19.5% vs. 6.3%), with minimal changes in the number of referrals per anomaly detected (13.4 vs.

CONCLUSIONS

Referral for targeted ultrasound in the presence of even minor abnormalities of amniotic fluid would significantly improve anomaly detection with minimal increase in referrals.

Three-dimensional color power imaging of the fetal hepatic circulation

OBJECTIVE

The purpose of this study was to describe the use of three-dimensional power Doppler ultrasonography to identify vascular congenital anomalies of fetal portosystemic and umbilical venous systems.

STUDY DESIGN

In a prospective study, the hepatic and umbilical venous systems were examined in 390 fetuses with two-dimensional ultrasonography, color, and spectral Doppler imaging. Fetuses suspected to have anomalies of the portal system and ductus venosus were additionally examined with three-dimensional power Doppler ultrasonography.

RESULTS

Vascular anomalies were identified in 8 fetuses (absent ductus venosus, n=4; direct connection between the umbilical vein and the right atrium, n=2; and direct connection between the umbilical vein and the inferior vena cava, n=2) out of the 310 in which the venous system could be adequately imaged (prevalence=2.6%). Three-dimensional power Doppler imaging showed the course of the umbilical vein, its relationship to the portosystemic circulation, and whether a ductus venosus was present.

CONCLUSION

Three-dimensional power Doppler ultrasonography can be used to image normal fetal hepatic and portal circulation, as well as identify anomalies of the fetal portosystemic and umbilical venous systems.