title: Multimodality image registration with software: state-of-the-art.
abstract: BACKGROUND
  Multimodality image integration of functional and anatomical data can be performed by means of dedicated hybrid imaging systems or by software image co-registration techniques. Hybrid positron emission tomography (PET)/computed tomography (CT) systems have found wide acceptance in oncological imaging, while software registration techniques have a significant role in patient-specific, cost-effective, and radiation dose-effective application of integrated imaging.
  
  
  OBJECTIVE
  Software techniques allow accurate (2-3 mm) rigid image registration of brain PET with CT and MRI. Nonlinear techniques are used in whole-body image registration, and recent developments allow for significantly accelerated computing times. Nonlinear software registration of PET with CT or MRI is required for multimodality radiation planning. Difficulties remain in the validation of nonlinear registration of soft tissue organs. The utilization of software-based multimodality image integration in a clinical environment is sometimes hindered by the lack of appropriate picture archiving and communication systems (PACS) infrastructure needed to efficiently and automatically integrate all available images into one common database.
  
  
  CONCLUSIONS
  In cardiology applications, multimodality PET/single photon emission computed tomography and coronary CT angiography imaging is typically not required unless the results of one of the tests are equivocal. Software image registration is likely to be used in a complementary fashion with hybrid PET/CT or PET/magnetic resonance imaging systems. Software registration of stand-alone scans "paved the way" for the clinical application of hybrid scanners, demonstrating practical benefits of image integration before the hybrid dual-modality devices were available.
authors.affiliation: AIM Program/Department of Imaging #A047, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA. Piotr.Slomka@cshs.org
authors.forename: Piotr J
authors.initials: PJ
authors.lastname: Slomka
authors.forename: Richard P
authors.initials: RP
authors.lastname: Baum
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging; D003952:Diagnostic Imaging / Q000379:methods*; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D011859:Radiography; D011877:Radionuclide Imaging; D012984:Software; D051598:Whole Body Imaging