Ultrahigh-field 7-tesla MRI has found brain cells that can become inflamed in the hippocampus, which could provide more detailed information early in the development of Alzheimer's disease.
Researchers from Stanford University used 7-tesla MRI to examine postmortem brain tissue from people with Alzheimer's, identifying what appeared to be iron-containing microglia. These specialized scavenger cells were found in the hippocampus, a part of the brain that is critical to memory formation.
The findings, published online in Neurobiology of Aging, suggest that 7-tesla MRI could be used to diagnose and monitor Alzheimer's patients earlier than is currently possible.
Lead author Dr. Michael Zeineh, PhD, an assistant professor of neuroradiology, and colleagues used MRI, computational analysis, and laboratory staining techniques to probe slabs of tissue taken from several places within the brain in five individuals who had Alzheimer's disease. These tissues were compared with brain specimens from five control subjects.
In four of the five specimens from the Alzheimer's patients, the researchers found black dots in the subiculum, a component of the hippocampus. No such abnormalities were found in the control subjects.
Zeineh and colleagues then carefully sectioned the tissue slabs into several hundred ultrathin sections; incubated those sections with stains that pinpoint the location of iron, microglia, amyloid plaques, and tau; and analyzed the resulting stain patterns.
The group found that iron, frequently engulfed by microglia, occupied the same spots in the subiculum in the Alzheimer's patients where 7-tesla MRI had found the black dots. Most of the microglia cells found in association with iron were in an activated, inflammatory state.
The study adds the new finding that inflamed, iron-associated microglia are present in the hippocampus in Alzheimer's and are observable by 7-tesla MRI, which could advance the scientific community's understanding of the disease.
