1. Ultrasound scans types
By Umber Zareen

2. Ultrasound A The A stands for amplitude
The sample on the right is that of a healthy eye
It is routinely used in ophthalmology as it allows distinction of different tissue types
This is possible as different tissues have different acoustic impedences
So one can tell if there is blood in the eye or malignant tumor even if say a cataract is in the way
The scan on right shows an initial spike at the beginning of the tumor (left arrow), and then below the blue arrows low internal reflectivity (jagged white line), and then a spike at the back of the eye (right arrow, indicating a tumour

3. Ultrasound B B is for babies
Actually it stands for brightness, but it is the procedure you use to produce images of foetuses in obstetric sonography
This is as ultrasound b works in order to produce a two dimensional image of what you are examining
In this method the amplitude controls the brightness of the spot which represents the reflection, the b for brightness giving rise to the name B-scan. So a single pulse of ultrasound passing into a series of tissues will give rise to a series of spots, with the brightness of the spots corresponding to the amplitude of the reflection from different layers. E.g, the series of layers shown in sections 3 and 4 in image at top of screen would give rise to the scan to the left of it

4. Obstetric sonography The image behind is that of a fourth month foetus
Obstetric sonography is mainly done to check on the development of the foetus
To check normal limb development and to see if there are any abnormailities

5. 3d obstetric sonography
In 3D fetal scanning, instead of the sound waves being sent straight down and reflected back, they are sent at different angles.
The returning echoes are processed by a sophisticated computer program resulting in a reconstructed three dimensional volume image of fetus's surface or internal organs, in much the same way as a CT scan machine constructs a CT scan image from multiple x-rays.
3D ultrasounds allow one to see width, height and depth of images in much the same way as 3D movies but no movement is shown.
There is no real medical reason for 3D ultrasound it is mainly just as a keepsake photograph