The brain-imaging technique shows the extent and pattern of shrinkage in the skull over a period of months, even when the loss of tissue is very small. The brain shrinks at a rate of about 0.1 per cent a year in healthy people. In Alzheimer's disease, the shrinkage rate is about 4 per cent, and it is even higher in the early stages of CJD.
The technique developed by Dr Nick Fox and colleagues at the National Hospital for Neurology and Neurosurgery in London, involves two scans taken some months apart, using magnetic resonance imaging, a non-invasive scanning technique. A computer is then used to superimpose the two scans so that doctors can identify tiny degrees of brain shrinkage. At present, CJD can only be confirmed by post-mortem examination. A biopsy of living brain tissue is also possible but the result is not conclusive. Liz HuntReuse content