Constrained Surface Controllers for Three-dimensional Image Data Reformatting 1 Martin J. Graves, MSc Richard T. Black, MSc David J. Lomas, MB, BChir This study did not require ethical approval in the United Kingdom. The aim of this work was to create two control- lers for navigating a two-dimensional image plane through a volumetric data set, providing two important features of the ultrasonographic paradigm: orientation matching of the navigation device and the desired image plane in the three-dimensional (3D) data and a constraining surface to provide a nonvisual reference for the image plane location in the 3D data. The first constrained surface controller (CSC) uses a planar constraining surface, while the second CSC uses a hemispheric constraining surface. Ten radiologists were asked to obtain specific image refor- mations by using both controllers and a commercially available medical imaging workstation. The time taken to perform each reformatting task was recorded. The users were also asked structured questions comparing the utility of both methods. There was a significant reduction in the time taken to perform the specified reformatting tasks by using the simpler planar controller as compared with a standard workstation, whereas there was no significant difference for the more complex hemispheric controller. The majority of users reported that both controllers al- lowed them to concentrate entirely on the reformatting task and the related image rather than being distracted by the need for interaction with the workstation interface. In conclusion, the CSCs provide an intuitive paradigm for interactive reformatting of volumetric data.  RSNA, 2009 Supplemental material: http://radiology.rsnajnls.org/cgi /content/full/2521081368/DC1 1 From the Department of Radiology (M.J.G., D.J.L.) and Department of Medical Physics & Clinical Engineering (M.J.G., R.T.B.), Cambridge University Hospitals National Health Service (NHS) Foundation Trust, Hills Rd, Cam- bridge CB2 0QQ, England. Received August 4, 2008; revi- sion requested September 23; revision received Decem- ber 10; accepted January 15, 2009; final version ac- cepted February 3. Supported by a grant from Cambridge Enterprises Limited, Proof of Concept fund, and with fi- nancial support from the Department of Health through the National Institute for Health Research Comprehensive Biomedical Research Centre award to Cambridge Univer- sity Hospitals NHS Foundation Trust in partnership with the University of Cambridge. Address correspondence to M.J.G. (e-mail: mjg40@radiol.cam.ac.uk ).  RSNA, 2009 ORIGINAL RESEARCH  TECHNICAL DEVELOPMENTS 218 radiology.rsnajnls.org ▪ Radiology: Volume 252: Number 1—July 2009 Note: This copy is for your personal non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, contact us at www.rsna.org/rsnarights.