Abstract:

Although research interest within functional imaging has moved towards applications of MRI, such as BOLD and perfusion imaging, there is a wealth of clinical experience in emission tomographic imaging techniques that make the use of these modalities relevant for the decades to come. This review touches upon the technical and practical issues that distinguish SPECT from PET, describes perfusion and metabolic changes observed in the dementias, compares the clinical utility of the two techniques, and reports data on clinical sensitivity and specificity, as well as diagnostic head-to head comparisons in dementia, and specifically Alzheimer's disease. While few centres have a genuine choice between PET and SPECT, either appears to be good enough to help with the differential diagnosis of dementia in difficult cases.