28 - Neuroimaging of cognitive disorders: commentary

Summary

When my career-long colleagues and I look back, we are struck by the wealth of accumulated knowledge derived from the structural imaging of patients with Alzheimer's disease (AD). While many of these advances were made possible by improvements in imaging hardware, creative image analysis protocols and new software tools, the key to improved understanding of AD was the interdisciplinary interactions across the fields of neuropathology, biology, and neuropsychology. We note also that much of the research reviewed in the previous chapters on AD and non-AD dementias would not have been possible without such interdisciplinary interactions and important advances in neuroimaging techniques that have taken place over the past two decades. In this brief commentary, we offer our highly personal view of three-dimensional tomographic imaging related to AD. We describe important research themes that emerged over the past 30 years and which continue to be successfully employed to understand and to ultimately prevent AD.

Hardware advances

The age of structural imaging in AD began with X-ray computed tomography (CT). In spite of the advances made with CT between 1975 and 1985 (see Figure 28.1), poor soft tissue contrast, beam hardening artifacts, and long acquisition times limited the descriptions of the gross atrophy and limited the systematic search for specific anatomical targets of AD. It was not until about 1979, about 7 years after CT first became available, that we identified cortical atrophy as the second radiological feature of AD that exceeded age effects (de Leon et al., 1979).