Magnetic Resonance Imaging (MRI) Practice Test

Which parameters would be adjusted to increase voxel volume?

1. FOV, slice thickness, and matrix

2. FOV, TR, and ETL

3. Slice thickness, ETL, and NEX

4. Matrix, slice thickness, and TR

The correct answer is: FOV, slice thickness, and matrix

Increasing voxel volume in MRI can be achieved by modifying parameters that directly influence the dimensions of the voxels acquired during the imaging process. Voxel volume is a function of the field of view (FOV), slice thickness, and matrix size. When the field of view (FOV) is increased, it allows for a larger area of tissue to be imaged, thus increasing the size of individual voxels. Adjusting slice thickness directly impacts voxel volume; thicker slices result in larger voxels as more tissue is included within each slice. Lastly, the matrix size relates to the resolution of the image. A smaller matrix size means fewer pixels across the same FOV, which leads to larger voxel volumes since they cover a greater area of tissue within each dimension. In contrast, parameters such as TR (repetition time), ETL (echo train length), and NEX (number of excitations) are generally associated with the timing and intensity of the scans rather than the physical dimensions of the voxel. These settings may influence image quality, total scan time, and signal-to-noise ratio but do not directly affect the size of the voxels themselves in a way that would increase their volume.