Acknowledgments

The authors thank Claudia Wheeler-Kingshott, Phil Boulby and Gareth Barker from the Institute of Neurology, Queen's Square, London and the UK Multiple Sclerosis Society for providing data for this work. We would also like to thank the following institutions for their generous support: UK Medical Research Council (PMM, SMS), UK Engineering and Physical Science Research Council (TEJB, SMS), Wellcome Trust (HJB), the EPSRC-MRC IRC "From medical images and signals to clinical information" (JMB, MWW), the Portuguese Foundation for Science and Technology (RGN).