Partial volume artifact occurs when echoes from adjacent structures are blended within a single voxel.

• A. Partial volume artifact
• B. Slice thickness artifact
• C. Section thickness artifact
• D. Ghosting artifact

Answer: (A)

Partial volume effect happens when more than one tissue type falls inside the same imaging voxel, so the signals from those tissues are averaged together. Because the voxel’s value represents the combined contribution of all tissues within that small volume, the image shows a blended or intermediate signal rather than a true representation of any single structure. This is exactly what’s described when echoes from adjacent structures are blended within a single voxel, leading to blurred borders and potentially misinterpreting tissue characteristics.

Think of it as the resolution of the system not being fine enough to isolate each structure completely. If you reduce the voxel size or improve the spatial resolution—deeper focusing, higher frequency, thinner slices, or finer sampling—you lessen this averaging and the image more accurately reflects the individual tissues at that location.

Other artifacts, such as ones arising from the imaging plane’s finite thickness or from motion, are different in origin: slice thickness or section thickness artifacts come from structures outside the intended plane contributing to the voxel, while ghosting stems from motion or temporal sampling issues. These are not about averaging within a single voxel, which is the defining feature of the partial volume effect.