Definition and Features of Four Dimensional Ultrasound

In short: The three dimensions are length, width and depth; the fourth is time, which brings the three-dimensional image to life. With 3D ultrasound the doctor has to rotate still pictures, while 4D ultrasound shows the three-dimensional image moving in real time. This article explains what four-dimensional ultrasound is and what its features are.

What are the three dimensions? What is the fourth one?

When we say three dimensions we mean length, width and height (depth), and that is what forms a holograph. The fourth dimension is time, which gives life for the three dimensions.

With three dimensional ultrasound, the doctor needs effort in rotating the pictures to take the third dimension which takes time, but the fourth dimensional ultrasound gives the third dimension at the exact time when needed. For that reason, it is called, “live three dimensional ultrasound.”

• This device can take photos in three different ways:

1 - Surface Imaging:

When taking photos of the fetus, with this process, it shows the body surface without penetrating the internal organs. With this, the treating physician can check on fetal wellbeing and check for multiple potential anomalies in the body, such as a cleft lip. It can also give a close and clear photo of the features of the fetus. These can be clear, just like photographic photos, and it can diagnose external organ anomalies like ear, nose, hand, foot issues. It can show some facial and body features, but it cannot diagnose Down syndrome: screening is done with the 11–14-week scan and blood tests (or cell-free DNA), and diagnosis needs CVS or amniocentesis. It can also show the shape and outline of a mass more clearly, but ultrasound alone cannot prove whether a tumor is benign or malignant; that needs specialist assessment and often a biopsy.

2- Penetrating tissues:

This is like the two dimensional ultrasound. It shows the integrity of internal fetal organs like the heart, kidneys, liver, stomach and the rest of the internal organs in three dimensions. It can show accurate size, and irregular shape.

3- Transparent imaging:

This gives photos of the skeleton of the fetus, just like X-ray pictures. Any anomalies of the skeleton will be obvious in addition to being able to observe jaw development.

The breast can be examined also which can show obvious tubers in addition to the Doppler which shows blood flow and its direction. We can study heart function for the patient or the fetus inside the uterus or study blood circulation in the tissues, in general. It can also help in assessing breast lumps and other masses in the body and in guiding biopsies, but a definite diagnosis of cancer requires examining a tissue sample.

These previously mentioned ways provide the four dimensioned scan advantages like:

• Enables the treating physician to have general comprehensive stereoscopic images which helps in accurate diagnosis and following live movements inside the human body in its three dimensions, and it plays a major role in taking biopsies or inserting catheters inside the body.
• The possibility of storing photos through the computer and studying their sections later. This has saved much time in examination and makes a second opinion very easy, if the treating physician needs to consult another physician or if he needs to study sections in more detail.
• The accurate diagnoses that can be achieved by these devices has made diagnosis easier and it minimizes the associated psychological stress on the patient as well as the effort and financial cost by minimizing assumptions and contradictions.
• Accurate measurement for internal organs if they have an irregular shapes.

All these advantages have forced the world to push and rush development, and to make scientific revolutions in two dimensional ultrasound. It can achieve good results in diagnosis, but it needs this kind of revolution to give it the best results and finest details.

Dr Najeeb Layyous F.R.C.O.G

Consultant Obstetrician, Gynecologist and Infertility Specialist