How is voxel size affected by changing the FOV from 30cm x 30cm to 30cm x 20cm, keeping other parameters the same?

Voxel size is determined by the field of view (FOV), image resolution, and slice thickness in magnetic resonance imaging. When the FOV is changed from 30 cm x 30 cm to 30 cm x 20 cm while keeping other parameters constant, the pixel dimensions are altered based on the new FOV.

In the original scenario, with a 30 cm x 30 cm field of view, the voxel dimensions would be determined by the division of this 30 cm area into a certain number of pixels based on the image resolution. When the FOV is reduced to 30 cm x 20 cm, the area available for imaging in one dimension is decreased while the other dimension remains the same.

As a result, the total volume of each voxel decreases because voxel size is a function of the area covered by the pixels multiplied by the slice thickness. When one of the dimensions of the FOV decreases while maintaining the same pixel count across the unchanged dimension, it results in a smaller voxel size. Therefore, changing the FOV from 30 cm x 30 cm to 30 cm x 20 cm leads to a decrease in voxel size.