Medical images contain information (in two, three, and four dimensions) that is important to the clinician in diagnosis, evaluation, and treatment. New methodologies and tools make it possible to extract, interpret, integrate, and displty that information very effectively. This paper describes some of the application areas, gives examples of the tools now available and under development, identifies the benefits and costs of the new approaches, examines the issues in evaluation and validation, and looks at opportunities for ftirther improvements.Multimodality registration allows the clinician to combine images from several sources (e.g., PET, MRT, CT) for use in diagnosis, treatment planning (surgery, radiotherapy), and training (simulators for interventional radiology). Modem computing resources make it possible to do this rapidly enough to be useful clinically. The variety of techniques in use makes it difficult to compare, evaluate, and validate alternative methods. Some conclusions from a recent series of international workshops will be presented, and an example of a simulator described.Segmentation, and shape analysis and description are important for characterizing regions of an image. The regions can be used for registration, or for making measurements to quantify change. Consistency of performance may be improved if a method avoids manual steps, and thus in many systems the goal is to create an automated system with no user-specified parameters. Some new techniques (to be described briefly) come very close to achieving that goal.A clinician's evaluation of image data can be aided by methods that reveal structure otherwise inaccessible to the human eye-brain. In ultrasound data, for example, there is often valuable information in the high-order statistics of the image; this would not be visible without special processing. A set of methods has been developed for making this information available, and relating it, with high probability, to diagnostic categories.Examples and discussion of clinical relevance will be included, along with mention of issues in evaluation and comparison (performance, computational cost) of alternative methods.A.
Issues in multimodality image registrationA group of more than 20 international experts in the fields of medicine, defense, and intelligence was convened to define the image-registration problem in detail and propose technologies needed to solve the problem. The experts provided inputs by e-mail and met at three careftilly structured workshops in 1997 to discuss and develop solutions for image registration problems. 4 SPIE Vol. 3747 • 0277-786X/99/$1 0.00 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/21/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx