الفهرس 
coverOnly 14 pages are availabe for public view
 |  | from | 107 |  |  |
| | | from | 107 | | |
Abstract
Ultrasonography is a non invasive procedure that is har mless to the
fetus and t he mot her, high frequency ultrasound is utilized to produce
visible images from the pattern of t he echoes made by different t issues
and organs, including t he baby in the amniot ic cavit y. Recognit ion of t he
major int ernal organs to detect any abnormalit y can best be accomplished
between 16 to 20 weeks of gestat ion . In utero diagnosis of congenit al abnor malit ies can oft en be achieved wit h careful evaluat ion of the lesion, associat ed addit ional findings,and evolut ion over time (Mc Namara &Levine, 2005). Three-dimensional ultrasonography provides several tools (e.g., multiplaner imaging, surface rendering, volume rendering, and color power Doppler imaging). Also it can be used for studying the fetal
circulation and surrounding anatomic structures (Lee et al., 2003). Post-processing techniques of 3D ultrasound has greatly enhanced our knowledge of fet al anomalies and contribut ed to our understanding of how these affect pregnancy outcome (Simona et al., 2002). The advantages of 3DUS and 4DUS in certain areas are obvious. Its use in assessment of fet al anomalies is already implement ed by most centers. The use of this tool in applying color Doppler, in guiding needles for puncture procedures, as well as in assessing the fetal circulat ions, are under close research evaluation .
3DUS is useful for evaluating fetal abnormalit ies as a supplement to 2DSUS, part icular ly for abnormalit ies of the face, ears, fingers, an anatomic axis, but 3D US is unlikely to be helpful for detecting intrafet al abnormalities except for skelet al abnormalit ies and some pathologic changes wit h fluid accumulat ion as sur face-rendered images of the fetus with oligohydramnios and the fetus wit h thin skin or thin subcutaneous tissue were difficult to obtain wit h 3D US, so 2D US still the gold st ander in this situat ions Last ly, Three-dimensional and four dimensional sonography largely remains an exciting research tool in it s application in congenit al anomalies of the fetus. Three-dimensional sonography offers too much to be ignored and will gradually become commonplace in most unit s .