Diagnostic procedures are an integral part of the medical field. In-depth knowledge about physical and pathological conditions can be obtained through various diagnostic procedures. In pregnancy, all diagnostic producers can not be done due to the potential fetal side effect of the procedures. Ultrasonography is one of the safest diagnostic tests during pregnancy to assess various conditions. One of the newest advantages of ultrasound technology is the 4D ultrasound technique. This technology provides real-time data about fetal conditions.
What Is the Ultrasound in Gynecology?
Gynecological ultrasound or gynecological sonography is a non-invasive technique. In this procedure, ultrasound sound waves are projected toward the organs through a transducer. These soundwaves bounce off the organs like an echo and are captured by the transducer, which then processes these data from a two-dimensional image of the object. The most commonly used method for ultrasound in gynecology is the trans-abdominal approach. This method is very useful for imaging the abdominal structure. Pelvic structures are viewed through the anterior abdominal wall in this method. As a result, several errors may happen. These are:
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As the distance between the transducer and the pelvic region increases, a lower frequency must be used to minimize image distortion.
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The beam degrading effect of the anterior abdominal wall, specifically in obese patients, distorts the images.
The transvaginal approach for ultrasound was first introduced in 1985. This method reduces the distance between the probe and the pelvic structures, allowing the use of higher frequency for better image quality.
4D ultrasound is the modification of the three-dimensional ultrasound technique. This is also called real-time ultrasound. Unlike the three-dimensional ultrasound, the images taken in this procedure are continuously updated and the image acquisition speed is much higher. As a result, a real-time view of the three-dimensional structs can be possible. In 4D ultrasound scanning, echo is captured by a truncated cone with its vertex located at the transducer. After this, the collected information is optimized through different mechanisms like thresholding, magic cut, and vocal-volume calculation. Through computer-guided navigation, more data is obtained and analyzed and an image is generated.
What Is the Advantage of 4D Ultrasound Scanning?
The main advantage of 4D ultrasound scanning is a real-time image. Other advantages are:
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Images can be viewed in different planes.
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Multi-slice image is obtained.
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Transparent mode off display can be obtained.
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Filtering of the image and color selection can be done.
What Is the Use of 4D Ultrasound Scan?
The potential use of a 4D scan can be divided into two parts. One is used in fetal scans and another in identifying gynecological abnormalities.
What Is the Role of 4D Fetal Scan?
Several fetal structures can be identified properly, indifferent to a plan to identify any abnormalities.
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In the first trimester, fetal movement can be identified using a 4D ultrasound scan. In this period, only gross fetal movement can be visible. The complex movement of the hand and the head is visible towards the end of the first trimester.
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Facial expressions and frequent eye movements can be identified from the second trimester. First eye movement occurs in the 18th week of pregnancy. Around 24 to 26th of weeks of pregnancy, more frequent eye movement can be observed. During the last period of the second trimester, more frequent and complex facial expressions can be seen.
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Around the 15th week onwards, complex movements like hand-to-hand coordination, hand-to-head coordination, and isolated leg movements can be seen.
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Brain anomalies detection:Fetal brain anomalies can be identified through a 4D ultrasound scan. The brain images are obtained in three different anatomical levels. These are cerebellum and cisterna magna level, inferiorly, cavum septum pellucidum, and ventricular atria. Abnormalities at the cerebellum and cisterna magna level suggest Down syndrome. Cystic enlargement of the fourth ventricle is suggestive of Dandy-Walker malformation. Chiari II malformation (extension of brain tissue into the spinal cord) also can be identified at this level.
Midline development of the brain structures and its differentiation can be identified at the cavum septum pellucidum level. Holoprosencephaly (a condition that is caused by improper differentiation of the brain) can be identified at this level by ultrasonography. Colpocephaly caused by abnormal development of white matter in the posterior cerebrum is identified at this level. Intracranial hemorrhage and choroid plexus cysts can be identified while scanning at the ventricular atria level.
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Detection of spinal anomalies:4D ultrasound scanning provides views from different planes to identify spinal anomalies. Developmental malformations like spina bifida (a condition in which the spinal cord fails to close properly) can be identified using this ultrasound scanning. Structural defects of the special cord, like the hemi vertebra, wedge vertebra, and block vertebra, can be identified using the technique.
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Facial abnormalities like the cleft palate and the cleft lip can be identified priorly.
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Using 4D scanning, cardiac defects can be identified before birth. Conditions like ectopia cordis (a condition in which the fetal heart is present outside of the chest ), arterial septal defect, and coarctation of the aorta can be diagnosed.
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Measurement of lung volume and structural development of the lungs can be assessed using 4D scanning.
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Volumetric measurement of fetal arms and thighs can be done with the help of the 4D ultrasound. These are helpful in assessing the weight, growth, and development of the fetus.
What Is the Role of 4D Ultrasound in Gynecology?
Congenital defects in the uterus, like the bicornuate uterus (heart-shaped uterus), and septate uterus (uterus with a partition in the middle) can be identified using this technique. Multiple polyps and endometrial lesions and their flow blood flow patterns can be visualized more precisely by 4D ultrasound. Defects in the fallopian tube and tubal patency can also be analyzed non-invasively with the help of transvaginal 4D ultrasound.
What Should Be Keep In Mind?
4D ultrasound scanning is nothing but prolonged exposure to B-mode ultrasound scanning. Such prolonged exposure to the fetal tissue may generate heat. This heat is calculated by thermal index (TI). Ideally, the heat is absorbed by local perfusion. Prolonged exposure can be harmful. The exposure time for 4D ultrasound should be less than 30 minutes to keep the thermal index under 1.
Conclusion:
Diagnostic imagining techniques have tremendous prognostic value in the medical field. 4D ultrasound can be very useful in determining various pathological conditions. Real-time and multi-planer views enable viewing the fetus and pathological condition in different planes. This aids in surgical planning also. Moreover, a real-time view of the fetus helps to establish a bond between the mother and the baby.
