Three-dimensional ultrasonographic bladder volume measurement: reliability of the Virtual Organ Computer-Aided Analysis technique using different rotation steps

Renal volumes measured by 3-dimensional sonography in healthy fetuses from 20 to 40 weeks

OBJECTIVES

The purpose of this study was to establish reference values for fetal kidney volumes as a function of gestational age, estimated by 3-dimensional sonography using the Virtual Organ Computer-Aided Analysis (VOCAL) technique (GE Healthcare, Kretztechnik, Zipf, Austria).

METHODS

Volumes of right and left kidneys were assessed in 213 healthy fetuses by 3-dimensional sonography using the VOCAL technique. Inclusion criteria were healthy women with singleton pregnancies, unremarkable comprehensive fetal sonographic findings, well-known gestational age established by first-trimester sonography, and gestational ages between 20 and 40 weeks. Exclusion criteria were patients lost to follow-up and birth weight abnormalities. Each patient was scanned once during pregnancy. Regression analysis was used to calculate unified formulas.

RESULTS

The mathematical models calculated in the study were as follows: expected right kidney volume = exp[-1.01 + (0.12 × gestational age)]; and expected left kidney volume = exp[-0.90 + (0.12 × gestational age)]. No significant intraobserver or inter-observer variability was observed for the determined volumes.

CONCLUSIONS

Reference values for right and left fetal kidney volumes throughout gestation using the rotational technique (VOCAL) are described. The use of this technique might aid in further definition of gestational age kidney volume standards to help in defining variations from the norm.

Assessment of postoperative postvoid residual bladder volume using three-dimensional ultrasound volumetry

The aim of our prospective study was to assess the concordance between postvoid residual volumes (PVR) of the urinary bladder obtained by two different three-dimensional (3-D) ultrasound (US) volumetric methods (VOCAL and XI VOCAL) and with measurement by the catheter in postoperative patients who have undergone radical hysterectomy. The 3-D sonographic volume-determination of PVR with both methods correlated significantly with the actual amount of PVR by the catheter. The accuracy of both 3-D US volumetric methods was significantly higher under 300 mL of PVR. Bland-Altman plots were generated to examine limits of agreement. Both noninvasive 3-D sonographic methods are appropriate for the correct volume-determination of PVR following radical hysterectomy. Thus, we may avoid routine, albeit often unnecessary, catheterization to measure postoperative residual bladder volumes and subsequently the incidence of lower urinary tract infection may be reduced and better postoperative comfort for patients may be permitted.

Effects of the maternal position and rest on the fetal urine production rate: a prospective study conducted by 3-dimensional sonography using the rotational technique (virtual organ computer-aided analysis)

OBJECTIVES

The purpose of this study was to determine the effect of the maternal left lateral decubitus position and rest on the fetal urine production rate.

METHODS

Fifty-four pregnant women with a normal amniotic fluid volume who had a singleton pregnancy between 26 and 40 weeks' gestation were included in this prospective study. Exclusion criteria included rupture of membranes, intake of any food or liquid within the previous 4 hours, and maternal or fetal complications. The amniotic fluid index was determined by averaging 2 or 3 repetitive measurements of the 4 amniotic fluid quadrants at the time of fetal urinary bladder volume measurements. The fetal urine production rate was measured using virtual organ computer-aided analysis. The amniotic fluid index and fetal urine production rate before and after the left lateral position rest period were compared by a paired Student t test. The Pearson correlation was used to study the relationships among the maternal age, gestational age, test time, amniotic fluid index, and fetal urine production changes.

RESULTS

The mean amniotic fluid indices ± SD before and after the rest period were 151.0 ± 45.0 and 172.5 ± 46.7 mm, respectively, indicating a significant increase in the amniotic fluid index (P < .05). The mean fetal urine production rates before and after the rest period were 73.7 ± 66.8 and 151.8 ± 119.9 mL/h, respectively, indicating a significant increase in fetal urine production (P < .05).

CONCLUSIONS

The fetal urine production rate and amniotic fluid index are markedly increased by maternal rest in the left lateral decubitus position.