A decrease in the voxel volume yields:

A decrease in the voxel volume yields:

• A. Increase Partial Volume Averaging
• B. Decrease Partial Volume Averaging
• C. No Change
• D. Increase Distortion

Answer: (B)

Partial volume averaging decreases when voxel volume is reduced. When a voxel is large, its signal can be a blend of multiple tissue types that lie within that voxel, causing the measured signal to be an average of those tissues and blurring boundaries. Shrinking the voxel volume makes each voxel sample a smaller, more uniform region, so it’s more likely to contain a single tissue type and therefore the signal better represents that tissue alone. This reduces partial volume effects and improves spatial detail. A practical trade-off is lower signal-to-noise ratio with smaller voxels, since fewer spins contribute to each voxel’s signal. Distortion is not directly dictated by voxel size in the same way; it’s more tied to sequence type, bandwidth, and geometric factors.

Partial volume averaging decreases when voxel volume is reduced. When a voxel is large, its signal can be a blend of multiple tissue types that lie within that voxel, causing the measured signal to be an average of those tissues and blurring boundaries. Shrinking the voxel volume makes each voxel sample a smaller, more uniform region, so it’s more likely to contain a single tissue type and therefore the signal better represents that tissue alone. This reduces partial volume effects and improves spatial detail. A practical trade-off is lower signal-to-noise ratio with smaller voxels, since fewer spins contribute to each voxel’s signal. Distortion is not directly dictated by voxel size in the same way; it’s more tied to sequence type, bandwidth, and geometric factors.