Toward MRI‐based whole‐brain health assessment: The brain atrophy and lesion index (BALI)

There have been many attempts to assess the elements of age‐ and dementia‐ related neurodegenerative changes in the brain using MRI; however, traditionally assessments focus only on single deficit. Over the past few years, our group has worked to create and validate the Brain Atrophy and Lesion Index (BALI) as an MRI‐based whole‐brain structural degeneration rating scale. The BALI can be used for applications in aging and dementia across the entire brain and can be applied to common clinical MR images. As a whole‐brain structural health assessment, the BALI gives a more representative picture of how the brain ages. During the aging process, multiple elements of degeneration accumulate and interact to overwhelm repair processes and cause high‐level failure in the function of the brain. To reflect this process, the BALI combines the assessment of several neurodegeneration changes into one scale. The BALI evaluation can be performed quickly and has been validated for use by non‐neuroradiology expert raters trained with the method. This review gives a brief overview of the content of the BALI; covers the development, refinement, and application of the method; and provides insights about future development and clinical implementation of MRI‐based whole‐brain health assessment in aging and dementia.