A new MRI ratio method for in-vivo estimation of signal hypointensity in aging and Alzheimer's disease.

1. Alzheimer's Disease (AD) is accompanied by a disruption in iron metabolism. There is no universally accepted method for detecting brain iron. 2. The authors have developed a novel "ratio" method which uses the red nucleus as an internal reference. We postulated that this method would improve our sensitivity in detecting differences in MRI signal intensities and that it would allow us to measure brain iron deposition. 3. The ratio method reasonably reproduced previous reports of the normal deposition of iron in brain that occurs with aging. It failed to distinguish any differences in three brain areas: putamen, left frontal lobe and whole slice in AD patients versus age and sex matched controls. 4. It also failed to detect differences with AD progression or severity. 5. The ratio method itself warrants further investigation.