**8. Conclusion**

142 From Preconception to Postpartum

Fig. 7. Using the MathCad computer programs, the vertical distances between marked pixels included in the bladder border was estimated. The bladder image was then electronically subdivided in vertical cylinders and the sum of these cylinders with the height of one pixel

The 3D ultrasound technique and integrated software, such as the "Virtual Organ Computer-aided AnaLysis" system (VOCALTM), are already available for volume estimation and measurements in the in vitro setting and are both reliable and valid (Raine-Fenning et al., 2003). Moreover, this technique has been applied to the fetal urinary bladder (Lee et al., 2007; Touboul et al., 2008). Unfortunately, the 3D technique is prone to the same types of problem encountered in 2D ultrasound imaging, plus others unique to volume acquisition and visualisation (Nelson et al., 2000). When selecting the initial bladder image, the operator can avoid shadows from the fetal pelvis. However, according to the VOCAL system, the subsequent process for volume estimation is automatic and disturbing shadows are not avoided. Furthermore, in this program, only 40 electronic points are available for the

equals the bladder volume.

**6.2 The 3D ultrasound technique** 

contour marking, which is another disadvantage.

The data suggest that, in fetal hypoxemia, there might be a redistribution of blood flow, with a reduction in both renal perfusion and fetal urine production rate, which can be estimated by ultrasound. These findings may be important, as it would be of great clinical interest to determine whether or not a particular fetus with growth restriction is further compromised. To utilise the HFUPR, for fetal surveillance, a program is available for estimating the risk of false readings at a low percentile point, even though the true HFUPR is at a higher percentile point, and the degree to which an observed HFUPR change can be explained exclusively by measurement error.
