by standard MR imaging in as many as 20% of subjects. The addition of diffusion weighted MR sequences to our protocol increased the number of positives to 33% (5/15). 
    Future questions we wish to pursue are the following; Do these imaging findings predict clinical course? Will the signal changes resolve with resolution of symptoms? What is the exact nature of the lesions detected on delayed DWI but not spin-echo T2? Do these findings correlate with other investigative findings such as baseline and full neuropsychology battery? Is there a correlation with neuropsychological and neurophysiological testing? (Dupuis et al. Neuroreport, 2000, Leclerc 2001 in prep ). Do imaging findings reflect repeated or cumulative injury? Our future prospective studies will address these important issues in our attempt to improve the diagnosis and management of sport related head injury.