Sonography-based Automated Volume Count to estimate fetal urine production in twin-to-twin transfusion syndrome: comparison with Virtual Organ Computer-aided AnaLysis.

Abstract

Sonography-based Automated Volume Count (SonoAVC) is an automated, operator-independent, 3-dimensional ultrasound technique. The study goal was to assess agreement between SonoAVC and Virtual Organ Computer-aided AnaLysis (VOCAL) for bladder volume measurements and fetal urine production (FUP). This was a prospective study of recipient bladder volumes in twin-to-twin transfusion syndrome acquired with SonoAVC and VOCAL every 2 minutes during 30 minutes before and 24 hours after laser coagulation. FUP formulas: (V(2) - V(1)) × 60/time interval in minutes; and slope of linear regression of ≥ 3 consecutively increasing bladder volumes × 60 minutes. Bland-Altman plots were used to compare techniques. In 38 pregnancies, 560 bladder measurements were acquired. Mean FUP was 7.29 mL/h (95% confidence interval, 5.66-8.92) using SonoAVC and 6.79 mL/h (95% confidence interval, 5.16-8.42) using VOCAL (P = .14). Limits of agreement were -0.20 to 0.22 cm(3). Fetal bladder volume and FUP measurements using SonoAVC were comparable to VOCAL. SonoAVC is operator independent, easy, and fast.