IMAGE DISPLAY TECHNIQUES

Question 1

What is a Pixel ?

Answer 1

On a ct scan there is a map/ grid made up of each attenuation value. One value or one square is called a pixel.

Question 2

What is a Voxel ?

Answer 2

It is the 3D equivalent to a pixel. The depth is dependant on the reconstruction slice width.

Question 3

What is Window width ?

Answer 3

This is the range of Hounsfield units you can display. Therefore controls the image contrast. If you have a higher window width the contrast will be higher also.

Question 4

What is Window level ?

Answer 4

This is the midpoint for the range displayed.

Question 5

What do you understand of MPR ?

Answer 5

Its multiplanar reformatting which enables you to use scanning data from helical scanning to be reformatted into different planes. Mostly from axial.

Question 6

What do you understand by a MIP ?

Answer 6

This is a maximum intensity projection. It displays the voxels with the highest density on each projection. e.g. if you want to view contrast filled spaces or bone.