[Show abstract][Hide abstract] ABSTRACT: To determine the sensitivity of first-trimester ultrasound for diagnosing different structural anomalies in chromosomally normal pregnancies, and to establish the role of aneuploidy markers in the detection of abnormalities.
This was a retrospective study of chromosomally normal singleton pregnancies with an 11-14-week scan performed in our center during 2002-2009. The ultrasound examination included an early fetal anatomy survey and assessment of nuchal translucency, ductus venosus blood flow and nasal bone.
Among 13 723 scanned first-trimester pregnancies with no genetic anomalies and complete follow-up, 439 fetuses (3.2%) were found to present with structural anomalies (194 with major anomalies and 245 with only minor anomalies). Forty-nine per cent of major structural anomalies were detected during the first-trimester scan, the highest rates corresponding to acrania (17/17), holoprosencephaly (three of three), hypoplastic left heart syndrome (10/10), omphalocele (six of six), megacystis (seven of eight) and hydrops (eight of nine). Higher than expected detection rates were obtained for skeletal (69%) and cardiac (57%) defects, coincidentally showing the highest presence of an increased nuchal translucency or abnormal ductus venosus blood flow (38% and 52%, respectively). The finding of an absent nasal bone did not appear to be associated with structural defects.
About half of major structural abnormalities can be diagnosed in the first trimester. Increased nuchal translucency or abnormal ductus venosus blood flow appear to be associated with cardiac and skeletal defects and may facilitate early detection.
Ultrasound in Obstetrics and Gynecology 08/2011; 39(2):157-63. · 3.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To evaluate the reproducibility of estimation of power Doppler-derived fractional moving blood volume (FMBV) in the uterine cervix of women with uncomplicated pregnancies.
Two experienced operators evaluated 30 uncomplicated singleton pregnancies at 20-24 weeks of gestation. The PDU box was positioned in a mid-sagittal view of the cervix, including the internal os and external os, in the same plane as that in which cervical length is measured. Two consecutive examinations were performed by each operator, in each of which the cervical length was measured and five consecutive good-quality images with PDU information were obtained. The region of interest (ROI) (cervix) was delineated offline and FMBV, which expresses the percentage of blood occupying the ROI, was calculated with purpose-designed software. Intra- and interobserver intraclass correlation coefficients (ICCs) and mean differences with 95% limits of agreement (LOA) were calculated.
The median gestational age at examination was 22 + 0 weeks. Measurements (median ± SD) obtained for cervical length and FMBV were as follows: Operator A: 37 ± 7.4 mm and 8.11 ± 2.9%; Operator B: 37.5 ± 9.3 mm and 7.9 ± 3.3%, respectively. The intra- and interobserver ICCs for FMBV were 0.88 (95% CI, 0.75-0.94) and 0.82 (95% CI, 0.64-0.94), respectively. There was a mean difference in FMBV measurement between operators of - 0.2 ± 1.75% (95% LOA, - 3.7 to 3.2%).
Reproducible assessment of cervical blood perfusion through estimation of FMBV can be achieved while cervical length is being measured.
Ultrasound in Obstetrics and Gynecology 02/2011; 38(1):57-61. · 3.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To assess the intra- and interobserver reliability of the umbilical vein (UV) diameter, time-averaged maximum velocity (TAMX) and umbilical vein blood flow (BF).
Sixty-three consecutive singleton pregnancies between 24 and 42 weeks were evaluated by two independent operators. UV diameter and TAMX were measured. UV flow was calculated as UV area x 60 x TAMX x 0.5. Reliability analyses were performed by means of the intraclass correlation coefficient (ICC) for agreement. Differences between and within observers were explored and agreement limits calculated by means of the Bland-Altman test.
Satisfactory Doppler parameters were successfully obtained from all fetuses. The intraobserver ICCs for UV diameter, TAMX, and BF were 0.7, 0.59, and 0.55, respectively, whereas the interobserver ICCs were 0.65, 0.46, and 0.60, respectively. The 95% confidence intervals of the intraobserver differences were (+0.15, -0.14), (+8.0, -7.9), and (+150, -138.7), respectively. The 95% confidence intervals of the interobserver differences were (+0.16, -0.16), (+8.5, -8.2), and (+138.8, -141.9), respectively.
Noninvasive Doppler calculation of umbilical vein blood flow and its components are reliable enough for clinical use.
[Show abstract][Hide abstract] ABSTRACT: Umbilical venous blood flow could be considered a direct and physiological measurement of vascular placental function, representing the quantity of oxygen and nutrients reaching the fetus. The advent of high-technology ultrasound and pulsed Doppler has overcome some of the limitations of early studies. Indeed, Doppler measurement of umbilical venous blood flow has been found to be accurate when compared with several gold standards for in-vivo flow calculation. Nevertheless, small errors in volume flow components, the vessel area and the mean velocity, result in large errors in the calculation of volume flow. Therefore, technique standardization is of paramount importance. Validation studies in animal models have demonstrated accurate venous blood flow measurements by estimating the vessel's cross-sectional area from perpendicular views of longitudinal sections of free-floating portions of the cord. On the other hand, estimation of the mean velocity from the maximum velocity, rather than using the intensity-weighted mean velocity, is less software-dependent and more clearly defined, yielding estimates with more predictable and systematic errors. By adhering to stringent methodological recommendations, umbilical venous blood flow calculation has moderate to good intra- and interobserver reproducibility. Having been found to be accurate and reproducible, further studies are required to establish the clinical value of umbilical vein flow measurement.
Ultrasound in Obstetrics and Gynecology 07/2008; 32(4):587-91. · 3.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To construct gestational age (GA)-based reference ranges for the uterine artery (UtA) mean pulsatility index (PI) at 11-41 weeks of pregnancy.
A prospective cross-sectional observational study was carried out of 20 consecutive singleton pregnancies for each completed gestational week at 11-41 weeks. UtAs were examined by color and pulsed Doppler imaging, and the mean PI, as well as the presence or absence of a bilateral protodiastolic notch, were recorded. Polynomials were fitted by means of least-square regression to estimate the relationship between the mean UtA-PI and GA.
A total of 620 women were included. A second-degree polynomial (Log(e) mean UtA-PI = 1.39 - 0.012 x GA + GA(2) x 0.0000198, with GA measured in days), after a natural logarithmic transformation, was selected to model our data. There was a significant decrease in the mean UtA-PI between 11 weeks (mean PI, 1.79; 95(th) centile, 2.70) and 34 weeks (mean PI, 0.70; 95(th) centile, 0.99). It then became more stable up until 41 weeks (mean PI, 0.65; 95(th) centile, 0.89).
The mean UtA-PI shows a progressive decrease until the late stages of pregnancy. Reference ranges for mean UtA-PI may have clinical value in screening for placenta-associated diseases in the early stages of pregnancy, and in evaluating patients with pregnancy-induced hypertension and/or small-for-gestational age fetuses during the third trimester.
Ultrasound in Obstetrics and Gynecology 05/2008; 32(2):128-32. · 3.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To analyze the interobserver reliability of measurement of the middle cerebral artery (MCA) pulsatility index (PI) at two different sampling sites.
This study included 100 consecutive singleton pregnancies between 24 and 40 weeks with normal fetal growth. The PI was calculated by two independent operators at proximal and distal sampling sites of the near-field MCA. Reliability analyses were performed between observers at each sampling site by means of the intraclass correlation coefficient (ICC) for agreement. Differences between observers were explored and agreement limits calculated by means of the Bland-Altman test.
Satisfactory flow velocity waveforms were obtained successfully in each fetus at both sampling sites. Peak systolic, end-diastolic and time-averaged maximum velocities were significantly higher at the proximal compared with the distal sampling site. Conversely, PI was significantly higher at the distal compared with the proximal site. ICCs for PI were 0.3 and 0.33 at the proximal and the distal sampling sites, respectively. The 95% interval of the PI differences between observers were +0.91 and -1.14 at the proximal and +1.03 and -1.08 at the distal sampling sites. In about 30% of the cases the PI difference between observers was greater than 0.5 at both sampling sites.
Moderate interobserver reliability in the measurement of end-diastolic and time-averaged maximum MCA flow velocities results in limited agreement of the PI calculation at both proximal and distal sampling sites. These results may preclude its clinical applicability.
Ultrasound in Obstetrics and Gynecology 12/2006; 28(6):809-13. · 3.14 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To analyse the inter-observer and inter-artery reliability of the umbilical artery (UA) pulsatility index (PI) at different sampling sites.
One hundred consecutive singleton pregnancies between 24 and 40 weeks were included. The PI was calculated by two independent operators from both umbilical arteries at the placental end, at a free-floating loop and at the perivesical segment. Reliability analyses were performed between observers and between arteries at each sampling site.
The mean percentage of PI difference between arteries was 15.2, 14.5 and 22% at the placental end, free-loop and perivesical site, respectively. The Intraclass correlation coefficients at each site were 0.51, 0.59 and 0.67, respectively. Whereas about 20% of cases showed a percentage of PI difference between arteries greater than 20% at free-loop and placental end sites, and at the perivesical site this figure was 45%.
The perivesical sampling site for UA PI calculation is more reliable than at a free-floating loop, albeit without significance, and is significantly more reliable than at the placental end of the umbilical cord. Since discordances in PI between both arteries are more pronounced at the perivesical site, it seems mandatory to evaluate both arteries in this segment.
Journal of Perinatal Medicine 02/2006; 34(5):409-13. · 1.43 Impact Factor