Alzheimer’s disease and the dawn of preventive neuroradiology

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In 1735, Benjamin Franklin wrote, “An ounce of prevention is worth a pound of cure.” Now 280 years later, this basic concept of human health has been refined and applied throughout medicine. Recently, the emphasis on prevention has been amplified by the passage of the Affordable Care Act that prioritizes such services. Radiology remains uniquely poised for this change with its application of imaging technology in preventive medicine. While the field of breast imaging stands out as a clear illustration of this concept with its ability to reduce breast cancer mortality, other examples are also present. The recent Center for Medicare & Medicaid Services approval to use chest CT scans to screen for lung cancer in at-risk populations is another application of radiology as a preventive specialty.

The current paper I co-authored with colleagues titled “Hot Topics in Research: Preventive Neuroradiology in Brain Aging and Cognitive Decline,” presents an encouraging model for applying brain imaging to preventive medicine.

The specific application to Alzheimer’s disease is a reflection of how that field of research has drastically changed over the past ten years. When I first started working as a medical student in the laboratory that invented amyloid imaging with Pittsburgh compound B in 2004, there was little to no discussion about preventing Alzheimer’s disease. We now know that as many as 3 million cases of Alzheimer’s dementia worldwide can be prevented with as little as a 10 percent reduction in the burden of preventable lifestyle factors.

Recent work by others has also taught us that the pathological process of Alzheimer disease typically starts at around age 50 — over a decade before the earliest clinical symptoms are detected. There is also an increasingly abundant literature on how structural, functional, and molecular brain imaging can help guide risk reduction of Alzheimer’s. In our review, we focused specifically on studies that demonstrate how just two lifestyle factors — obesity and physical activity — can influence brain structure and function. Obesity is shown in multiple investigations to be related to decreased gray matter volume on MRI and reduced blood flow on functional MRI. Physical activity is related to increased gray matter volume and improved brain blood flow by comparison. Both lifestyle factors affect common areas of the brain important for memory, learning, and Alzheimer’s pathology — most notably the hippocampus. Quantitative techniques are necessary to demonstrate and track these changes.

Neuroradiologists can help drive clinical care by providing such actionable information as hippocampal volumes to the growing number of neurologists, geriatric psychiatrists, and clinical neuroscientists who want to apply the best technology for patient care. One can envision a future in which patients at particular risk for cognitive decline by way of family history, genetics, and lifestyle receive a brain scan augmented by quantitative data. These measures may include a combination of structure, functional, and potentially even molecular markers. A prevention plan based on lifestyle modification can then be applied, and the results can be tracked with imaging and neuropsychiatric measures over time. The management of such data will require additional Big Data tools such as deep and causal learning algorithms. We have a long way to go before such a model becomes standard of care.

By converging with other clinical neuroscientists, however, preventive neuroradiology will improve our patients’ brain health.

Cyrus Raji is a radiology resident.  This article originally appeared in the AJNR Blog.

Image credit: Shutterstock.com

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