[1] Univ Manchester, Wolfson Mol Imaging Ctr, Manchester M13 9PL, Lancs, England
[2] Salford Royal NHS Fdn Trust, Dept Neurosurg, Salford, Lancs, England
[3] Univ London Imperial Coll Sci Technol & Med, Div Expt Med, London SW7 2AZ, England
[4] Salford Royal NHS Fdn Trust, Neuropathol Unit, Salford, Lancs, England