Technology assessment--an American view.

Technology assessment of an imaging method such as magnetic resonance (MR) is a complicated concept that includes aspects of epidemiology, biostatistics, clinical efficacy determination, outcomes assessment, and knowledge of the technical and medical bases of the imaging method under study. To enhance understanding of the interrelations of the different aspects of technology assessment, a hierarchical model is proposed. This extends from the basic imaging physics domain through clinical applications in diagnosis and treatment decisions to patient outcomes and ultimately societal considerations. This overview paper presents the conceptual continuum of the hierarchical model, and then describes the interrelationships among efficacy, cost effectiveness, and outcomes research as components embedded within the context of technology assessment. It also points out how scientific quality of research in MR imaging assessment can be enhanced through improved research design that takes into account basic concepts of the model.