How much is your brain worth? It is the three-pound universe that comprises all you know of yourself and your world. It is the most valuable organ you have and is more sophisticated than any computer. Without it you are not yourself.

Over five million Americans are not the same vibrant mothers and fathers, sisters and brothers they once were because their brains have been damaged and their memories stolen by Alzheimer's disease.

By 2025, their ranks could grow 40 percent -- to seven million -- according to the Alzheimer's Association.

In the ongoing battle against Alzheimer's, researchers have developed a new type of brain scan that can detect brain plaques that are characteristic of the disease.

The scanning technique capitalizes on a remarkable ability to use small doses of radioactive chemicals that will "stick" only to Alzheimer plaques in the brain.

A positive scan in a patient with memory loss strongly supports the diagnosis of Alzheimer's, whereas a negative scan makes it virtually impossible for Alzheimer's to be the cause of memory symptoms.

The scan is a giant step forward to improving the accuracy of diagnosis of patients with memory loss.

New technology is expensive. The scan costs several thousand dollars, and the Center for Medicare & Medicaid Services is currently deliberating whether to reimburse the costs of this new scan, known as amyloid brain imaging. Without reimbursement, this advanced and useful technology cannot be widely available to patients with memory symptoms.

Amyloid imaging is based on an improved understanding of Alzheimer's stemming largely from tax-supported research. Taxpayers support the National Institutes of Health, which advances research; companies use the information to build new devices or produce new drugs; taxpayers get new products for diagnosis and treatment.

The price of the new advances is high initially and declines with time. This cycle of discovery has dramatically decreased disease and increased the human life span.

But why would we want a life span that exceeds our brain span? The point of living longer is to enjoy life. Accurately diagnosing those with Alzheimer's and those with reversible mimics of Alzheimer's is critically important.

Amyloid imaging raises challenging new issues. The scan is positive in about 30 percent of cognitively normal older persons. These individuals have Alzheimer pathology in the brain but no cognitive symptoms.

Does this mean the scan in not useful? No. Some people with positive scans will never develop the clinical manifestations of the disease, but most will.

The Food and Drug Administration does not recommend the scan for those without symptoms, and clinicians are not requesting that CMS approve it for this purpose.

Patients with very mild symptoms, those with unusual cognitive symptoms, or persons with very early onset of symptoms are those most difficult to diagnose. These are settings in which amyloid imaging could be most helpful and in which CMS is being asked to reimburse the costs.

Why diagnose Alzheimer's if there is nothing that can be done? Currently we have no therapies that slow the disease process, so who would want to know if they have Alzheimer's?

The information is important because 50 percent of those with mild memory loss do not have Alzheimer's and 20 percent or those with more disabling symptoms and diagnosed with Alzheimer's dementia on the basis of clinical assessments have some non-Alzheimer condition that needs attention.

Those without Alzheimer's often have reversible causes of memory loss. Those with Alzheimer's can be started on the currently available medications, and patients and families can be counseled properly regarding prognosis.

Well-diagnosed patients can participate in clinical trials, contributing to the development of better therapies.

Avoiding an early accurate diagnosis of Alzheimer's is not an acceptable option and does not serve the patient's interests. Surely this new technology that promises to help us diagnose complex neurological conditions should be made available and reimbursed by CMS.

After all, how much is a brain worth?

Jeffrey Cummings, MD, ScD, is director of the Cleveland Clinic's Lou Ruvo Center for Brain Health. His research is supported in part by Avid Pharmaceuticals and he has served as a paid consultant for General Electric.