Alzheimer's disease (AD) is the most common cause of dementia and represents a major public health problem. From a clinical perspective, AD is devastating to patients and their families. The genetic approach to the study of dementia undoubtedly continues to provide a significant contribution to understanding the pathogenesis, diagnosis and therapeutic perspectives, but also raises important ethical implications. With advances in new technology, including genetics and PET/MRI scanning, the role of genetic studies and neuroimaging is being redefined as an aid in the clinical diagnosis of AD, and also in presymptomatic evaluation. Here, we review some of the issues related to the neuroimaging-genetic relationship in AD with a possible clinical implication as a preclinical biomarker for dementia and also for tracking disease progression.