Perspective from the Alzheimer's Association: Neuroimaging Professional Interest Area of ISTAART continues impact on the field.

More than 5 million Americans [1] and 35 million people worldwide are estimated to be living with Alzheimer's disease (AD) today, with the prevalence expected to quadruple by 2050 as the world's population ages [2]. Although Dr. Alois Alzheimer first described AD more than a century ago [3], [4], advances in therapy development have remained elusive. Today's current therapies provide symptomatic relief, and there is no evidence that they stop or slow the progression of the underlying disease process. The search for disease-modifying therapies has been hampered by a lack of knowledge about the course of the disease process. Data from clinical, imaging, biomarker, genomic, and other omic studies combined with electronic health records, payer claims, and new technologies that track real-time data should inform a better understanding of the earliest neuropathological and behavioral events that herald the oncoming disease.

The in vivo imaging biomarkers field for Alzheimer's disease and related disorders is rapidly expanding, and neuroimaging has emerged as a critical research and diagnostic tool in the field of AD and other dementias. In 2004, researchers from the University of Pittsburgh, led by Drs. William Klunk and Chet Mathis, reported for the first time at the Alzheimer's Association International Conference (AAIC; formerly the International Conference on Alzheimer's Disease) on an imaging agent called Pittsburgh compound B (PiB), a major potential breakthrough in disease monitoring and early detection. PiB enters the brain through the bloodstream and attaches itself to beta-amyloid deposits, where it can be detected by positron emission tomography (PET). This set the stage for the next decade of research on beta-amyloid imaging ligands. The Alzheimer's Association provided significant support to initiatives to develop PiB and conduct preclinical testing in animal studies.

Also in 2004, the Alzheimer's Disease Neuroimaging Initiative (ADNI) launched as a model of private and public partnership to establish standards for obtaining and interpreting brain images across the nation. In 2005, the Alzheimer's Association provided $2.4 million in funding for the ADNI PiB add-on study which was pivotal in our understanding about the accumulation of beta-amyloid in later life. Findings resulting from ADNI have influenced the field in dramatic ways [5]. For example, ADNI data influenced Jack et al. to develop one of the most widely accepted models of temporal dynamics of biomarkers in the development and progression of AD [6], [7], [8]. This hypothetical model creates a change in how the global research enterprise considers the disease landscape, supporting the deliberations that ultimately led to the 2011 revised National Institute on Aging–Alzheimer's Association (NIA-AA) guidelines for AD diagnosis [9], [10], [11], as well as informing the design of large scale AD studies that are currently testing methods that may delay or even completely prevent the onset of dementia symptoms in individuals whose biomarkers suggest they are in the pre-symptomatic phase of the disease [12].

The Alzheimer's Association created the International Society to Advance Alzheimer's Research & Treatment (ISTAART) in 2008 to facilitate connection of researchers across the globe around specific scientific topic areas. Within ISTAART, affinity groups called Professional Interest Areas began, and one of the first focused on neuroimaging and continues to grow and expand engagement of the scientific community. Consistently, the neuroimaging PIA leadership of researchers has fostered a spirit of collaboration and an emphasis on awards that recognize junior investigators making exceptional advances in neuroimaging-related research.

The neuroimaging PIA organizes the Alzheimer's Imaging Consortium (AIC) as a 1-day preconference for AAIC; the AIC focuses on the clinical application and methodological development of neuroimaging (MRI, PET, SPECT, CT, and others) to AD, other dementias, and normal brain aging. As an integral component of AAIC and a highly anticipated annual meeting, the AIC brings together nearly 1000 researchers from around the world for the latest science as neuroimaging continues to advance our understanding of AD and related dementia. Furthermore, the leadership of the neuroimaging PIA advocated and aligned initiatives to publish this special volume of Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring as a way to capture and highlight the AIC advances.

In 2015, the neuroimaging PIA established an educational workshop to convene leading experts for this 1-day multimodal program, with an emphasis to provide information and training to a broad audience of stakeholders, engaging the larger research community in learnings surrounding neuroimaging. The inaugural workshop in 2015 was a half day, and in 2016, this workshop became a 1-day event focused on in-depth understanding and an update of the fundamental principles, inherent limitations, and the latest in clinical and research applications of the most prominent neuroimaging modalities in the dementia field. Together, the full day workshop trains diverse stakeholders on the role of neuroimaging and the importance of the imaging techniques to comprehensively probe the molecular, cellular, and system-level neurodegenerative changes in the brain [13].

Both, the AIC and the neuroimaging workshop at AAIC as well as the emphasis on this special volume, are examples of the strong leadership and impact of the Neuroimaging PIA on the broader field; these activities provide vehicles that further advance research discovery into the emerging area of neuroimaging and its development as a critical research and diagnostic tool in the field of Alzheimer's disease and other dementias. The Alzheimer's Association recognizes the tremendous volunteers who actively participate in the ISTAART neuroimaging PIA, implementing important resources for the field and making the PIA's work a continued reflection of the research community's commitment to foster enterprising discoveries and build on these findings for the next advancements.