3D and 4D Ultrasound

What Is 3D Ultrasound?

This is a technique where a large amount of image data is produced as the ultrasound probe is scanned across a volume of tissue.  Once the sweep of the probe has occured, the sonographer is able to view the volume of data in several ways.  Surfaces can be viewed where there are adjacent tissues of different fluidity.  For example, if the face of a fetus is surrounded by amniotic fluid, an image of the facial features, just like a conventional photograph, can be obtained, including light and shadows.  It should be noted however that if the fetal face is up against the wall of the uterus, optimal views of the fetal face cannot be obtained. 

Another use is in solid organs.  A curved structure, such as the uterus, can be imaged as if it has been straightened out, significantly assisting the diagnosis of focal endometrial thickening and endometrial polyps. Scans of other organs can also benefit from this technology.

3D imaging is available at most CRG branches

4D Ultrasound

This is simply 3D scanning performed on a continual basis.  Instead of obtaining just one surface display, it is possible to see a fetal face, for example, moving in real time.  4-D scanning allows the sonographer to optimise the 3D images that can be obtained.  The 4D movie images can be saved as digital video clips.  Again, successful 4D imaging depends on the surface being investigated being surrounded by fluid. 4D ultrasound has been available to St Georges Radiology for several years, and is currently being extended throughout the practice.

CRG's Policy on 3D and 4D scans

CRG aims to have this technology available throughout all its sites by mid 2009.

We will endeavour to provide optimal 3D or 4D images whenever there appears to be a clinical need, in terms of diagnosing possible abnormality eg cleft palate in a fetus.

For more routine scans, we will obtain 3D or 4D scans so long as fetal position permits, and at no extra charge.  However, we will not undertake prolonged scanning for the main purpose of providing nice images for the family album.  To do so would disrupt our schedule, and contravene the recommendations of most professional ultrasound organisations.

If women are insistent on 4D images, and we have been unable to produce them during a routine scan, they will be re-booked at specific times, but will be expected to pay extra, as such scans will not be covered by Health Benefits.