الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Central nervous system (CNS) malformations are the second most frequent category of congenital anomaly, after congenital heart disease. Ultrasound (US) detection of prenatal central nervous system (CNS) anatomic anomalies is very important in deciding on therapeutic termination. It is a non-invasive technique, which is more acceptable by patients. Several studies have shown an accuracy of 92% to 99.7% for US detection of CNS anatomic anomalies.
Magnetic resonance imaging (MRI) has become an important diagnostic tool in obstetrics. It is non-invasive doesn’t depend on ionizing radiation, has super soft-tissue contrast resolution, and capable of multidirectional imaging with a large field of view, making the visualization of complicated anomalies easier. The use of MR imaging for in-utero evaluation of pathological conditions of the CNS is becoming widely accepted as an adjunct to fetal ultrasonography studies. Magnetic resonance imaging is thought to characterize CNS anomalies better, and to provide a more accurate diagnosis and prognosis.
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Ultrasound remains the predominant modality for evaluating disorders related to the fetus and pregnancy overall. Ultrasound continues to have several obvious advantages over MRI. It is safe and relatively inexpensive and is a widely available technology that allows for real-time imaging. US provides superior spatial resolution, permits assessment of fetal well being, and provides a quantitative assessment of fetal and placental blood flow with Doppler US.
While ultrasound remains the imaging modality of choice for the fetus because of its widespread availability and reasonable cost, it has several limitations. These include the small field of view, limited soft tissue acoustic contrast, and suboptimal performance in specific conditions such as oligohydramnios, maternal obesity, and limited visualization of the posterior fossa after 33 weeks’ gestation because of bone calcification.
The purpose of this study was to determine the added value of fetal MR imaging in different fetal CNS abnormalities that were seen initially on prenatal sonograms
Our work has come to the conclusion that:
The use of MRI after the 1st trimester of pregnancy is safe
US is the primary imaging screening method for pregnancy
Fetal MRI is to be used as complementary imaging whenever there is a strong suspicion of complex fetal anomalies, whether by US, or there is a family history or previous pregnancies with fetal anomalies, and especially in the third trimester, when cranial ossification is masking the posterior fossa.