Evaluation of new diagnostic imaging technologies.

New imaging technologies have to be evaluated for safety and for utility taking into account the uniqueness of the biological feature examined, the quality of the anatomical visualization, and accuracy of diagnosis. Comparative studies establish whether the new technology complements or replaces older methods, and what contribution it makes to therapeutic strategies. Historically, there were three phases: that of the great lone innovators, from whose efforts new techniques diffused; that of the large cooperative studies by academic clinicians and, recently, with the advent of MRI (magnetic resonance imaging), the phase of publicly appointed assessors, such as the FDA (Food and Drug Administration, USA). The methods of the latter two are detailed and critically compared. Evaluation in the clinical setting is more comprehensive. Therapeutic benefit, and not just image quality, has to be the ultimate consideration.