What is an effect of increasing slice thickness on partial voluming?

Increasing slice thickness in MRI indeed leads to increased partial voluming. Partial voluming occurs when a voxel, which is the smallest distinguishable box-shaped part of a 3D image, contains multiple tissue types. As slice thickness increases, the probability that each voxel captures multiple anatomical structures or different tissues rises, which can blur the boundaries between these tissues.

Increased slice thickness means that more tissue is sampled within a single slice. Consequently, if a voxel encompasses both fat and muscle, for example, the resultant signal is an average of those different tissues rather than being specific to one type. This averaging effect can lead to inaccuracies in interpreting the image, as transitions between tissues can appear less defined and more blended.

While there are benefits to increasing slice thickness, such as improvements in signal-to-noise ratio (SNR) due to capturing more signal, it does not negate the fact that it raises the risk of partial voluming. Therefore, the correct understanding is that increasing slice thickness results in greater partial voluming effects in MRI imaging.