Role of 3D and 4D Ultrasound in Assessing Fetal Abdomen Anomalies

Introduction:

Modern 3D and 4D sonography have been amazing diagnostic tools that help visualize the early embryo and fetus during pregnancy. With proper use of this technology, both the structural and developmental stages of the fetus can be determined in the first trimester of pregnancy.

Recently, 3D and 4D ultrasound has evolved into powerful techniques used in routine examinations. This helps identify normal and abnormal fetal structures in the more detailed imaging mode. However, the 3D and 4D technologies are not as useful as standard ultrasounds for prenatal (before birth) diagnosis; therefore, usually in pregnancy, normal ultrasounds are recommended.

What Is Ultrasound?

An ultrasound is a diagnostic imaging technique that uses sound waves to create a picture of the internal organs, tissues, and other structures of the body. This is also known as a sonogram. It is a non-invasive device that does not use radiation like X-rays to produce the image. Moreover, it can produce live images of the body structures in motion, such as the heart beating or blood flowing through blood vessels.

Generally, there are two categories of ultrasounds which include -

• Diagnostic Ultrasound - This is used to evaluate the inner parts of the body, such as the heart, liver, kidneys, bladder, blood vessels, and female reproductive organs. The primary function of this is to find any abnormality and to check whether they are functioning properly.

• Pregnancy Ultrasound - In pregnancy, ultrasound is used to look at the unborn child and to check its growth, development, and overall health.

What Are 3D and 4D Ultrasonography?

Generally, the majority of people have at least one ultrasound in their life or during pregnancy as a part of routine prenatal care. The type of ultrasound done is usually a standard 2D one, which provides all the necessary information. These are performed only for medical reasons or diagnostic purposes.

On the other hand, 3D and 4D ultrasounds are not commonly done, and the only advantage is the images are more detailed, and the fetus can be seen in 3D instead of 2D. Moreover, the clinical applications of 4D ultrasound technology are still being studied, and the long-term effects of these lengthy ultrasound exposures are unknown.

When Can a 3D or 4D Ultrasound Be Performed?

The ideal time for a 3D or 4D ultrasound scan is during the 26 to 30 weeks of pregnancy. During this time, the baby has little fat under the skin, and therefore, the bones are visible. However, the face is unclear during this time as it goes down in the pelvis. Limbs and extremities can be easily distinguished.

Viewing the 3D or 4D images of the baby can be helpful in non-medical ways by increasing the bonding with the baby rather than diagnosing problems. Moreover, these scans require special transducers and software, which are expensive and therefore affect their availability.

What Is the Goal of 3D and 4D Ultrasounds?

• The main goal of 3D and 4d ultrasound is to provide accurate information which will help in getting the possible outcomes for the mother and fetus, which is essential during early pregnancy.

• The end of the first trimester can help in the detection of any fetal abnormalities.

• In the second trimester (18 to 22 weeks) scan, which is considered the standard scan during the pregnancy, helps in evaluating whether it is a low-risk or high-risk pregnancy.

What Are the Applications of 3D or 4D Ultrasound in Gynecology?

The 3D and 4D ultrasounds have the following applications in gynecology which include -

Uterus -

• Endometrial evaluation.

• Investigation of uterine anomalies.

• Localization of intrauterine devices.

Ovary -

• Folliculometry (series of ultrasound examinations to monitor the growth of follicles in the ovary).

• Investigation of ovarian masses.

• Ovarian blood flow.

Fallopian Tube -

• Assessment of tubal patency.

• Investigation of postinflammatory tubal changes and tubal masses.

Pelvis -

• Investigation of endometriotic lesions.

• Surface rendering of the pelvic floor.

What Skeletal Abnormalities Can Be Diagnosed in a Fetus Using 3D and 4D Sonography?

Various types of skeletal dysplasias can be diagnosed using 3D ultrasonography. Given below are some of the skeletal abnormalities along with their clinical findings, which include -

Campomelic Dysplasia -

• Micrognathia (small lower jaw).

• Flat face.

• Hypoplastic scapulae (congenital abnormality of scapula bone).

• Bifid foot (congenital deformity of the foot).

Achondroplasia -

• Improved characterization of frontal bossing and depressed nasal bridge.

• Superior evaluation of the epiphysis and metaphysis of the long bones, with a demonstration of a vertical metaphyseal slope.

• Caudal narrowing of the interpedicular distance.

• Clear visualization of the trident hand.

• Better visualization of disproportion between limb segments.

Achondrogenesis -

• Short neck and severe shortening of all segments of the limbs.

Jarcho-Levin Syndrome -

• Vertebral defects with the absence of ribs and transverse process.

Larsen Syndrome -

• Genu recurvatum (knee bends backward, also called knee hyperextension).

• Midface hypoplasia (a condition in which the mid part of the face, including the upper jaw, cheekbones, and eye sockets, have not fully grown).

• Low-set ears (abnormal shape or position of the outer ear).

Platylospondylic Lethal Chondrodysplasia -

• Enhanced visualization of femoral and tibial bowing.

• A better description of the facial soft tissues with surface rendering.

What Are the Advantages of 3D and 4D Ultrasound During Pregnancy and Prenatal Checkups?

The majority of the time, 3D and 4D scans are done to see the baby in the womb and to keep the high-quality images as a collection. However, these scans do provide information regarding various internal organs or pathological structures. Given below are some of the examples of information that can be gathered using 3D and 4D scans -

During Prenatal Check-up -

• Developmental anomalies.

• Location of the placenta.

• Examination of placenta previa.

• Bone shape abnormalities like club feet, cleft palate, spina bifida, dwarfism, and a fusion of bones.

• Fetal biopsy.

• Kidney dilatation and uropathy.

• Fetal health, such as abnormal gestures.

• Fetus movements such as respiratory movements, movements of eyelids, limbs, and mouth, and deglutition.

• Fetal neuro-myopathy diseases include muscle reactions and the tonicity of muscles.

Fetal Cardiac Function:

This includes fetal cardiac activity and abnormalities such as

• Correlation between valves, chambers, and vessels.

• The volume of heart cavities.

• Communication between atrial and ventricular communication.

• Assessment of valvular function.

• The outflow of blood from ventricles.

• Communication between atrial and ventricular chambers.

What Are the Disadvantages of 3D and 4D Ultrasounds?

• 3D or 4D ultrasounds are a form of new technology and are not available everywhere.

• The armamentarium required for these procedures is expensive, which affects its availability.

• Required longer training to operate the machinery.

• The data acquired may be of lower quality during fetal movements of any kind.

• Shadows may appear in the scan that may reduce the quality.

Conclusion:

The use of 3D and 4D ultrasonography can facilitate getting detailed images of the fetus along with any abnormalities. This may help in prenatal diagnosis and counseling of parents if any abnormality is present. However, it does not offer additional resources to examine the fetus, such as in multiple planes, which is possible in the 2D scan. Additionally, more research is needed regarding the role of 3D and 4D ultrasounds in improving the diagnosis of congenital anomalies.