ULTRASOUND SCANNING

Does Ultrasound Scanning Could Detect All Accurate Diagnose Of Fetal Anomalies In Pregnant Women?



Table of Content

CHAPTER-I: INTRODUCTION3

Objectives of the Research4

Significance of the Study5

CHAPTER-III: LITERATURE REVIEW6

Fetal motility- Early investigations6

Ultrasonographic Investigations8

Screening or Diagnosis11

Need to Define Purpose11

Evaluation of Test Performance12

CHAPTER-III: CONCLUSION29

REFERENCES31

CHAPTER-I: INTRODUCTION

Ultrasound is used for different reasons at different stages in pregnancy. In the first stage of the pregnancy, usually before 14 weeks, ultrasound scanning is used to check whether the foetus is alive and whether it is alone or one of twins or triplets. By measuring the length of the foetus it is also possible to accurately determine when the baby will be due.

Some major abnormalities can also be detected at this stage. At 11 to 14 weeks, measurement of the thickness of the skin at the back of the neck (known as nuchal translucency measurement) can be used to calculate the risk of the foetus having a chromosome abnormality.

Benvenuti, et al (2008) mentions from 18 weeks onwards, it is possible to examine the foetus in more detail. Most organ systems can be examined to ensure that the foetus appears to be developing normally. The spine, skull, brain, heart, lungs, kidneys, arms and legs can all be seen. If the mother is overweight, then the quality of the examination may be poor.

From 30 weeks onwards, ultrasound is often used to estimate how well the baby appears to be growing. It is difficult to be precise about this but it is often useful if the woman has had a small baby in the past or has a condition that may affect the baby's growth, such as pre-eclampsia. The bloodstream in the umbilical cord is also examined to see if it is functioning well enough to transport sufficient oxygen and nutrition to the foetus. It is also possible to check the position of the placenta to see whether it is lying normally or if the placenta is lying abnormally close to the inside of the cervix (a condition known as placenta praevia).

Obstetric Ultrasound is the use of ultrasound scans in pregnancy. Since its introduction in the late 1950's ultrasonography has become a very useful diagnostic tool in Obstetrics. Currently used equipments are known as real-time scanners, with which a continous picture of the moving fetus can be depicted on a monitor screen (Benvenuti, et al, 2008). Very high frequency sound waves of between 3.5 to 7.0 megahertz (i.e. 3.5 to 7 million cycles per second) are generally used for this purpose.

They are emitted from a transducer which is placed in contact with the maternal abdomen, and is moved to "look at" (likened to a light shined from a torch) any particular content of the uterus. Repetitive arrays of ultrasound beams scan the fetus in thin slices and are reflected back onto the same transducer.

The information obtained from different reflections are recomposed back into a picture on the monitor screen (a sonogram, or ultrasonogram). Movements such as fetal heart beat and malformations in the feus can be assessed and measurements can be made accurately ...