Using magnetic resonance imaging (MRI), researchers may be able to predict which adults with mild cognitive impairment (MCI) are more likely to progress to Alzheimer's disease.  Individuals with MCI develop Alzheimer's  Disease at a rate of 15 to 20% per year, which is significantly higher than the 1 to 2% rate for the general population. Some people with MCI remain stable while others gradually decline and some quickly deteriorate.  Linda K. McEvoy, from the University of California/San Diego School of Medicine (UCSD; California, USA), and colleagues analyzed MRI exams from the Alzheimer's Disease Neuroimaging Initiative (ADNI), which performed imaging and other tests on hundreds of healthy individuals and others with MCI and early AD between 2005 and 2010 in hopes of identifying valuable biomarkers of the disease process.  Included in the study were a baseline MRI exam, serving as an initial point of measurement, and a second MRI performed a year later on 203 healthy adults, 317 patients with MCI and 164 patients with late-onset AD. The average age of the study participants was 75.  Using MRI, the researchers measured the thickness of the cerebral cortex — the outermost layer of the cerebral hemispheres of the brain that plays a key role in memory, attention, thought and language — and observed the pattern of thinning to compute a risk score. One of the characteristics of AD is a loss of brain cells, called atrophy, in specific areas of the cortex. Using the baseline MRI, the researchers calculated that the patients with MCI had a one-year risk of conversion to AD ranging from 3 to 40%.  "Compared to estimating a patient's risk of conversion based on a clinical diagnosis only, MRI provides substantially more informative, patient-specific risk estimates," observe the researchers.