Relationship between aortic isthmus and ductus venosus velocity waveforms in severe growth restricted fetuses.

OBJECTIVE: To evaluate the incidence of abnormalities in velocity waveforms from ductus venosus (DV) and aortic isthmus (AoI) in fetuses with intrauterine growth restriction (IUGR) and their reciprocal temporal relationship. METHODS: DV and AoI velocity waveforms were recorded in 31 IUGR fetuses characterized either by absent end diastolic (20) or reverse flow (11) in umbilical artery. Abnormal velocity waveforms in DV and AoI were defined in presence of reverse diastolic flows. RESULTS: Abnormal DV velocity waveforms were present in 10 fetuses and were always associated with abnormalities. Abnormal AoI flows were also present in 10 fetuses of the remaining 21 fetuses with normal DV velocity waveforms (47.6%). Longitudinal monitoring of fetuses with normal DV flows showed a significantly shorter time interval in the onset of reverse flow in DV when abnormalities in AoI were present (4 vs 14 days p=0.001) irrespectively of gestational age or other potential confounding variables. CONCLUSIONS: Our data suggest that AoI velocity waveforms become abnormal at an earlier stage of fetal compromise than DV.

Use of the 3-vessel view to record Doppler velocity waveforms from the aortic isthmus in normally grown and growth-restricted fetuses: comparison with the long aortic arch view.

OBJECTIVE: Aortic isthmus (AoI) velocity waveforms are considered powerful indicators of hemodynamic deterioration in intrauterine growth-restricted (IUGR) fetuses. However, technical difficulties in sampling AoI velocity waveforms from the longitudinal aortic arch (LAA) have limited its clinical application thus far. In this study, we tested the possibility of recording AoI velocity waveforms from the 3-vessel (3V) view of the fetal mediastinum and comparing the agreement of these measurements with recordings from the LAA. METHODS: Doppler measurements of the pulsatility index (PI) from the AoI were performed in 70 fetuses (20 IUGR and 50 normally grown) between 20 and 34 weeks' gestation. All measurements were sampled in both the LAA and 3V views by the same investigator. Reliability was evaluated with intraclass correlation coefficients (ICCs), and Bland-Altman plots were generated. The time required to complete the measurements was compared. RESULTS: A high degree of reliability was observed between PI values obtained from LAA and 3V views in both IUGR and normally grown fetuses (all fetuses: ICC, 0.976; 95% confidence interval [CI], 0.961-0.985; normally grown: ICC, 0.839; 95% CI, 0.731-0.906; IUGR: ICC, 0.954; 95% CI, 0.886-0.982). However, recordings from the 3V view were significantly less time-consuming than those from the LLA view (mean +/- SD, 30.4 +/- 14.2 versus 52.8 +/- 29.4 seconds; P < .0001) and showed higher intraobserver reproducibility. CONCLUSIONS: In IUGR and normally grown fetuses, AoI waveforms can be reliably obtained from the 3V view with higher reproducibility and a shorter recording time.

Examination of the fetal heart by four-dimensional ultrasound with spatiotemporal image correlation during routine second-trimester examination: the 'three-steps technique'.

OBJECTIVE: To prospectively analyze the accuracy and rapidity of four-dimensional (4D) ultrasonography with spatiotemporal image correlation (STIC) in the assessment of four-chamber view and outflow tracts in unselected fetuses and in fetuses with congenital heart defects (CHD) at 19-23 weeks of gestation. MATERIALS AND METHODS: 112 consecutive pregnancies undergoing routine second-trimester ultrasonographic scan and 10 pregnancies with fetuses with CHD affecting the great arteries formed the study group. From the four-chamber view, volumes of the fetal heart were acquired by the STIC technique and stored for a later offline analysis that was performed by two examiners blinded to the characteristics of the fetuses. Offline analysis was performed using a simplified multiplanar approach based on 3 different steps and one rotation finalized to visualize the four-chamber view and the left and right outflow tracts. RESULTS: Adequate recognition of four-chamber view and outflow tracts was obtained in more than 80% of the volumes. There were no false-positives and only one observer had a false-negative (interrupted aortic arch classified as normal). The mean time required to interpret 4D volumes was 3.7 min. CONCLUSIONS: The standard fetal cardiac anatomy survey can be performed in the second-trimester fetus by 4D STIC in both normal and abnormal hearts. This approach may reduce the operator's dependency in diagnosis of CHD.

Role of tomographic ultrasound imaging with spatiotemporal image correlation for identifying fetal ventricular septal defects.

OBJECTIVE: The purpose of this study was to test the possibility of diagnosing ventricular septal defects (VSDs) by using tomographic ultrasound imaging (TUI) on 4-dimensional volumes of the fetal chest obtained with spatiotemporal image correlation and the color Doppler function. METHODS: We retrospectively evaluated the 4-dimensional spatiotemporal image correlation volumes of 8 fetuses with VSDs (single in 7 and double in 1) between 20 and 33 weeks' gestation. The data were analyzed to determine whether VSDs were correctly identified in at least 1 of 7 automatically generated TUI displays. RESULTS: All of the included VSDs were correctly identified with the use of an interslice distance in the TUI function ranging from 0.8 to 2 mm without the need to further manipulate the volume. CONCLUSIONS: This automatic approach shows good retrieval of diagnostic cardiac planes in fetuses with VSDs, which may improve the diagnostic accuracy for this disease.

Application of automated sonography on 4-dimensional volumes of fetuses with transposition of the great arteries.

OBJECTIVE: The purpose of this study was to assess, in second-trimester fetuses with transposition of the great arteries (TGA), the performance of software (sonographically based volume computer-aided analysis) that automatically retrieves diagnostic cardiac planes from a 4-dimensional volume of the fetal chest obtained with spatiotemporal image correlation. METHODS: We retrospectively evaluated the 4-dimensional spatiotemporal image correlation volumes of 12 fetuses with TGA (complete TGA, 10 cases; correct TGA, 2 cases). The data were analyzed to determine whether the target diagnostic planes, that is, cardiac plane 1 (left ventricle outflow tract) and cardiac plane 2 (right ventricle outflow tract), were correctly identified in at least 1 of the 7 automatically generated tomographic sonographic image displays and whether they allowed diagnosis of TGA. RESULTS: In 9 of 10 fetuses with complete TGA, target diagnostic cardiac plane 1 showed a branching arterial vessel (pulmonary artery) arising from the left ventricle, whereas in 7 of 10 fetuses, the aorta arising from the right ventricle was shown. In both cases with correct TGA, the pulmonary artery starting from the morphologic left ventricle was shown, whereas in 1 of 2, the connection of the aorta with the morphologic right ventricle was found. In all of the fetuses with TGA, a ventricular arterial connection anomaly was shown in either cardiac plane 1 or 2. CONCLUSIONS: This automatic approach shows good retrieval of diagnostic cardiac planes in fetuses with TGA, which may improve diagnostic efficacy for this disease.

First trimester uterine Doppler and three-dimensional ultrasound placental volume calculation in predicting pre-eclampsia.

OBJECTIVE: To compare the efficacy of uterine artery Doppler velocimetry and three-dimensional ultrasound placental volume calculation alone or in combination in predicting at 11-14 weeks of gestation those pregnancies who will develop pre-eclampsia. STUDY DESIGN: This was a prospective study of 348 nulliparous women scheduled for a routine prenatal ultrasound examination at 11-14 weeks. Color and pulsed wave Doppler was used to obtain uterine artery flow velocity waveforms transabdominally and the mean pulsatility index (PI) of the uterine arteries was calculated. The placental volume was measured by three-dimensional ultrasound using the virtual organ computer-aided analysis. Outcome variables considered were pre-eclampsia and pre-eclampsia requiring delivery <32 weeks. RESULTS: Pre-eclampsia developed in 4.1% of the patients studied and in 1.7% a delivery before 32 weeks was required. Placental volume resulted significantly lower in pregnancies who will develop pre-eclampsia (t=4.636, p<0.003) and this was particularly evident in those pregnancies delivering <32 weeks (t=9.704, p<0.0002). No relationship was found between placental volume and mean uterine artery PI (r=-0.08, p=0.327). Uterine artery PI and placental volume showed similar sensitivities in predicting pre-eclampsia (50% vs. 56%) and pre-eclampsia with delivery <32 weeks (66.7% vs. 66.7%). The combination of uterine artery PI and placental volume gave better results when compared to the single use of one of these parameters (pre-eclampsia sensitivity 68.7%, pre-eclampsia requiring delivery <32 weeks 83.3%). CONCLUSIONS: The combination of abnormal uterine artery Doppler and low placental volume at 11-14 weeks achieves better results than does either test alone in the prediction of pre-eclampsia.

Fetal cardiac stroke volume determination by four-dimensional ultrasound with spatio-temporal image correlation compared with two-dimensional and Doppler ultrasonography.

OBJECTIVE: To assess the agreement of stroke volume (SV) measured with two-dimensional (2D) ultrasonography with Doppler capability (vs) four-dimensional (4D) with spatiotemporal image correlation (STIC) in normal and growth restricted fetuses. METHODS: 2D Doppler and 4D STIC were used to measure SV of 40 normal fetuses at 20 to 22 and 28 to 32 weeks, and 16 growth-restricted fetuses at 26 to 34 weeks of gestation. Intraclass correlation was used to evaluate the agreement between left and right SV obtained by the two techniques, and proportionate Bland-Altman plots constructed. The time necessary to obtain SV was analyzed. RESULTS: The intraclass correlation coefficient between 2D Doppler and 4D STIC measurements for the left ventricle were 0.977 and 0.980 for the right ventricle. The proportionate limits of agreement between the two methods were 18.7 to 23.9% for the left ventricle and - 20.9 to 21.7% for the right ventricle. The time necessary to measure SV was significantly shorter with 4D STIC (3.1 (vs) 7.9 min p < 0.0001) than with 2D Doppler. CONCLUSIONS: There is a good agreement between SV measured either by 2D Doppler or by 4D STIC. The 4D STIC represents a simple and rapid technique to estimate fetal SV and promises to become the method of choice.