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Objectives: To compare XI VOCAL (eXtended Imaging Virtual Organ Computer-aided AnaLysis) for three-dimensional (3D) ultrasound volumetry of the placenta and of phantom objects with a rotational method using VOCAL and with the multiplanar method. Methods: We acquired 3D volume datasets from 32 fetuses at 11-14 weeks' gestation. Placental volume was calculated twice by each of two observers using XI VOCAL (with 5, 10, 15 and 20 slices), multiplanar (1-mm interval) and VOCAL (with 12 degrees, 18 degrees and 30 degrees rotation) methods. In addition, validity was assessed using the in-vitro setting with three phantom objects of known volume. Results: Both inter- and intraobserver reliabilities were very high for all three methods. There was no systematic bias between any two methods except between XI VOCAL (10 slices) and the multiplanar (1-mm interval) method, with a smaller volume using the former method. The limits of agreement were wide between any two of the three methods. In the in-vitro setting, there was a trend towards less valid measurements with the XI VOCAL technique and fewer slices. With the same number of steps, measurements made with VOCAL (12 degrees and 18 degrees) were more valid than were those made with XI VOCAL (15 and 10 slices, respectively). Conclusion: XI VOCAL cannot be used interchangeably with VOCAL or multiplanar techniques in measuring placental volume at 11-14 weeks' gestation. [ABSTRACT FROM AUTHOR]

Objective: To compare the predictive values of three ultrasonographic parameters: placental thickness (PT), fetal cardiothoracic ratio (CTR) and middle cerebral artery peak systolic velocity (MCA-PSV), alone or in combination, in pregnancies affected by homozygous alpha(0)-thalassemia at 12-20 weeks' gestation. Methods: Pregnant women at risk of carrying a fetus affected by homozygous alpha(0)-thalassemia were studied from 1995 to 2006 using serial ultrasonography at 12-15 weeks, 16-20 weeks and 30 weeks' gestation. We measured CTR and PT from 1995, and MCA-PSV as well from 1997. An invasive prenatal test was offered if cardiomegaly with or without placentomegaly was detected but the MCA-PSV results were used only retrospectively for analysis. Results: Of a total of 777 at-risk fetuses studied, 138 (17.8%) were affected by homozygous alpha(0)-thalassemia. At 12-15 weeks' gestation, 598 ultrasound examinations were performed. CTR was better than both PT and MCA-PSV in the prediction of affected pregnancies. The highest sensitivity (98.3%) was achieved by the combination of CTR and/or MCA-PSV at a false-positive rate of 15.8%. At 16-20 weeks' gestation, 410 ultrasound examinations were performed, 121 of which were at the patient's first visit and 289 of which were at a follow-up visit. Both CTR and MCA-PSV predicted the affected pregnancies equally well. The sensitivity of CTR was 100.0%, but the false-positive rate was 5.2%. In contrast, the false-positive rate of MCA-PSV alone was 1.4% and that of the combination of CTR and MCA-PSV was 0%, although their sensitivities were less than 65%. Conclusions: The data suggest that adding MCA-PSV to CTR in the prediction of homozygous alpha(0)-thalassemia can increase the sensitivity at 12-15 weeks and decrease the false-positive rate at 16-20 weeks' gestation. [ABSTRACT FROM AUTHOR]

Objectives: To compare the new XI VOCAL (eXtended Imaging Virtual Organ Computer-aided Analysis) for three-dimensional (3D) ultrasound measurement of fetal volume with the conventional multiplanar technique and a rotational method using VOCAL. Methods: We acquired 3D volume datasets from 30 fetuses at 11-14 weeks of gestation using a commercially available ultrasound system. Fetal volume was calculated using XI VOCAL (with 5, 10, 15 and 20 slices), multiplanar (1-mm interval) and VOCAL (with 12 degrees, 18 degrees and 30 degrees rotation) techniques. The level of agreement for interobserver and intraobserver variability was determined and evaluated for all methods and reliability was assessed. Results: Fetal volume measurements obtained using XI VOCAL (10 slices) showed good correlation with those obtained using VOCAL (18 degrees) (r = 0.940, P = 0.076; intraclass correlation coefficient (ICC), 0.962 (95% CI, 0.920-0.982), P = 0.182), and XI VOCAL (15 slices) showed good correlation with VOCAL (12 degrees ) (r = 0.961, P = 0.092; ICC, 0.979 (95% CI, 0.957-0.990), P = 0.190). The mean difference between paired measurements by the XI VOCAL (10 slices) and VOCAL (18 degrees ) methods was 1.00 mL, while that by the XI VOCAL (15 slices) and VOCAL (12 degrees) methods was 0.90 mL. 95% limits of agreement were - 2.80 to 4.80 between XI VOCAL (10 slices) and VOCAL (18 degrees) and - 1.90 to 3.70 between XI VOCAL (15 slices) and VOCAL (12 degrees). There was a small difference in the time required to complete the fetal volume measurement between XI VOCAL and VOCAL when a similar number of slices or rotational steps was used (P < 0.05), XI VOCAL taking less time. Conclusion: XI VOCAL (with 10, 15 and 20 slices) can be used interchangeably with the multiplanar technique (1-mm interval) for the measurement of fetal volume. XI VOCAL (10 slices) and VOCAL (18 degrees) can be used interchangeably, as can XI VOCAL (15 slices) and VOCAL (12 degrees), for the measurement of fetal volume. [ABSTRACT FROM AUTHOR]