Application of the parametric scan in the investigation of uteroplacental blood flow.

We developed a new radioisotope technique to measure placental blood flow for the early detection of placental insufficiency. Using the parametric scan, placental perfusion was measured in 80 late-pregnant women. The T-maximum pictures obtained made it possible to differentiate between the vascular and intervillous phases of placental blood flow. The time period of intervillous phase calculated as the percentage of the whole placental Tmax was given as the intervillous perfusion index (IPI). It was demonstrated that the IPI was significantly higher in pregnancies complicated with intrauterine growth retardation (64.2% +/- 16.5%), hypertension (60.0 +/- 15.2) and oedema (57.9% +/- 10.1%) than in the control group (33.7% +/- 10.5%). These data suggest that the first sign of placental insufficiency is the prolongation of the IPI which is likely to precede the quantitative reduction of placental perfusion.