الفهرس 
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Abstract
The placenta is materno-fetal organ with chorionic (fetal) villi bathed in maternal blood spaces, which allows restricted transfer of metabolites and drugs across specialized transfer areas. The placenta develops respiratory, nutritive and excretory functions while the fetal organs mature, and is also an important endocrine organ. Examination of the placenta and gravid uterus is an integral part of obstetric sonographic study. There is large variety of techniques for placental imaging. Presently, ultrasound and to much lesser extent magnetic resonance imaging are the options of choice for imaging of placenta in health and disease. Methodical sonographic evaluation of the placenta should include: location, visual estimation of the size (and, if appearing abnormal,measurement of thickness and/or volume), implantation, morphology, anatomy, as well as a search for anomalies,such as additional lobes and tumors. Additional assessment for multiple gestations consists of examining the intervening membranes (if present). Doppler velocimetry is the ideal clinical tool to assess placental performance in high-risk pregnancies. It also has value in predicting later complications and outcome in pregnancies which appear uncomplicated. The assessment of umbilical blood flow provides information on blood perfusion of the fetal– placental unit. The diastolic blood flow velocity component in umbilical artery increases with advancing gestation. The 3D-power histogram was used to determine the placental vascular indices: vascularization index (VI), flow index (FI) and vascularization-flow index (VFI). The placental vascular indices were then plotted against gestational age and placental volume. All placental vascular indices showed constant distribution throughout gestation. A tendency for a reduction in placental vascular indices with increased placental volume was observed, but was only statistically significant when placental FI was considered (p < 0.05). All placental vascular indices estimated by 3D power Doppler ultrasonography presented constant distribution throughout gestation, despite the increase in placental volume according to gestational age The placenta is easy to image with a wide range of magnetic resonance imaging (MRI) pulse sequences, including quantitative imaging sequences.This is because the placenta is relatively immobile, and its blood volume is very large: approximately 50% of the whole placental volume. The magnetic susceptibility of all fetal tissues and the surrounding maternal tissues is similar, minimizing image artefacts resulting from differences in magnetic susceptibility between air and tissue found in other parts of the body. Furthermore, the rate of perfusion through the placenta is large, making it feasible to monitor this sensitively with MRI .
Objectives: Aim of the work is to study different methods of uteroplacental imaging in normal and some abnormal pregnancy diseases.