Location of Regional Brain Stiffness Differs in Common Dementia Types

Quantitative MR elastography (MRE) of changes in brain viscoelastic structure shows unique regional brain stiffness patterns among common dementia subtypes, according to a study published in the American Journal ofRoentgenology.

Researchers from the Mayo Clinic in Rochester, MN, sought to investigate age-corrected brain MRE findings in subjects with Alzheimer disease, dementia with Lewy bodies, frontotemporal dementia, and normal pressure hydrocephalus, and determine the potential use as a differentiating biomarker in dementia subtypes.

The study included 84 participants who all underwent MRE:

• 20 with normal pressure hydrocephalus

• 8 with Alzheimer disease

• 5 with dementia with Lewy bodies

• 5 with frontotemporal dementia

• 46 cognitively normal control subjects

Using shear waves of 60-Hz vibration frequency transmitted into the brain using a pillow-like passive driver, the researchers determined brain stiffness in eight regions:

• Cerebrum

• Frontal

• Occipital

• Parietal

• Temporal

• Deep gray matter–white matter

• Sensorimotor cortex

• Cerebellum

The results showed regional stiffness patterns unique to each dementing disorder. Patients with Alzheimer disease and frontotemporal dementia showed decreased cerebral stiffness with regional softening of the frontal and temporal lobes. They also additionally showed parietal lobe and sensorimotor region softening. Patients with normal pressure hydrocephalus showed stiffening of the parietal, occipital, and sensorimotor regions and those with dementia with Lewy bodies did not show significant stiffness changes in any of the regions.

The researchers concluded that quantitative MRE of changes in brain viscoelastic structure showed unique regional brain stiffness patterns among common dementia subtypes.