This chapter offers a highly personal view of three-dimensional tomographic imaging related to Alzheimer's disease (AD). The age of structural imaging in AD began with X-ray computed tomography (CT). CT studies introduced the negative angulation acquisition plane to more efficiently reveal and measure temporal horn enlargement and incidentally found evidence for hippocampal atrophy. Structural imaging has been invaluable in anatomically defining the regional tissue vulnerability and atrophy correction as estimated by fluorodeoxyglucose positron emission tomography (FDG-PET) and amyloid imaging and other tracers. Structural imaging owes a great debt to pathology for the contributions made to understanding the lesions and pathologic anatomy of AD. Although magnetic resonance imaging (MRI) imaging has yet to deliver a specific marker of AD pathology, MRI has provided sensitive characterizations of the effects of AD pathology and the promise of new MR contrast agents for identifying amyloid plaque pathology.