Parametric image analytical methods are becoming increasingly favored over traditional ROI analysis. The advantages are two-fold: 1) it removes the need for labor intensive region drawing and TAC processing, and 2) it makes it possible to demonstrate effects in regions that may be overlooked by ROI analysis. The flexibility and comprehensive nature of parametric image processing generally comes at the expense of reduced sensitivity to detecting effects in specific regions.
The steps to performing parametric image analysis include all the preprocessing steps except for drawing ROIs and generating TACs. In the case of parametric imaging, each pixel is effectively an ROI.
The general procedure for doing parametric image analysis with SPM is as follows: