Magnetic resonance imaging of the placenta in intrauterine fetal growth restriction

Intrauterine growth restriction occurs when the foetus fails to attain its genetically determined potential size. The present study was carried out to test the hypothesis that placental MR morphology and signal intensity measurements could differentiate between normal placentas and placentas in early or late intrauterine growth restriction. Normal and growth restricted foetuses were studied by Ultrasound and MRI at varying weeks of gestation. 98 growth restricted foetuses and 61 normal foetuses were included in the study. Ultrasound was done on a Siemens Antares ultrasound machine and MRI on a Siemens 1.5 Tesla system. Data was collected pertaining to gestational age, foetal weight and placental appearance by Ultrasound and MRI. Post processing signal intensity measurements of placenta were obtained. Echogenic cysts and echogenic cotyledons were seen more frequently in the placenta of IUGR foetuses by ultrasound. Globoid appearance of placenta in MRI denoted IUGR (p<.005). Placental signal intensity calculated by Region of Interest (ROI) showed a decline in normal pregnancies with advancing gestational age and significant difference between normal and IUGR placentas. Significant difference was found in T2 weighted Amniotic Fluid/Placental signal intensity ratios between normal and growth restricted pregnancies. MR evaluation of the placenta provides significant contribution towards assessment of IUGR placentas. Evaluation of the placenta should be done in any antenatal MRI study and MRI may play a role in future in management of Placental insufficiency.