Newer subtraction and filtration techniques.

This article attempts to describe and superficially evaluate the present and future application of a number of newer subtraction techniques, including recursive temporal filtration, matched filtration, hybrid subtraction, tomography and tomosynthesis, and parametric imaging and image processing. At this time, it is difficult to put each of these techniques into proper focus with regard to future clinical use. Suffice it to say that these and other techniques, which will almost certainly arise as our technical base expands, show promise of providing the diagnostician with unique information that will expand our ability to provide improved patient care based on better understanding of the physiology as well as the anatomy of both normal and pathologic processes. Critical evaluation of both the comparative clinical usefulness and the cost of such innovative digital technology requires careful study in academic centers before widespread commercial dissemination into the general diagnostic imaging community is warranted.