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

Abstract

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.

In vivo perfusion measurements in the human placenta using echo planar imaging at 0.5 T

“…There are no measurements of placental perfusion with which to compare these results. In an earlier study (3) radioisotope techniques were used to detect changes in utero-placental blood flow, in compromised pregnancy. The transit of the isotope across the placenta in the vascular and intervillous phases was extracted from the time-activity curve.…”

Human placental perfusion measured using dynamic contrast enhancement MRI

“…Thus, Ftotal shows that the placental weight differ between IUGR and AGA but does not reflect placental functional parameters, which should be explained by F. Two authors evaluated placental perfusion in humans and found very similar F mean values. In an earlier study, Bodis et al [ 30 ] used isotope techniques to estimate placental perfusion and found F mean of 110 mL/min/100ml. Gowland et al [ 31 ] performed echo planar imaging at 0.5 T in 15 patients and found F mean of 176±24 mL/min/100ml.…”