The brain health index: Towards a combined measure of neurovascular and neurodegenerative structural brain injury

Int J Stroke. 2018 Oct;13(8):849-856. doi: 10.1177/1747493018770222. Epub 2018 Apr 19.

Abstract

Background A structural magnetic resonance imaging measure of combined neurovascular and neurodegenerative burden may be useful as these features often coexist in older people, stroke and dementia. Aim We aimed to develop a new automated approach for quantifying visible brain injury from small vessel disease and brain atrophy in a single measure, the brain health index. Materials and methods We computed brain health index in N = 288 participants using voxel-based Gaussian mixture model cluster analysis of T1, T2, T2*, and FLAIR magnetic resonance imaging. We tested brain health index against a validated total small vessel disease visual score and white matter hyperintensity volumes in two patient groups (minor stroke, N = 157; lupus, N = 51) and against measures of brain atrophy in healthy participants (N = 80) using multiple regression. We evaluated associations with Addenbrooke's Cognitive Exam Revised in patients and with reaction time in healthy participants. Results The brain health index (standard beta = 0.20-0.59, P < 0.05) was significantly and more strongly associated with Addenbrooke's Cognitive Exam Revised, including at one year follow-up, than white matter hyperintensity volume (standard beta = 0.04-0.08, P > 0.05) and small vessel disease score (standard beta = 0.02-0.27, P > 0.05) alone in both patient groups. Further, the brain health index (standard beta = 0.57-0.59, P < 0.05) was more strongly associated with reaction time than measures of brain atrophy alone (standard beta = 0.04-0.13, P > 0.05) in healthy participants. Conclusions The brain health index is a new image analysis approach that may usefully capture combined visible brain damage in large-scale studies of ageing, neurovascular and neurodegenerative disease.

Keywords: Atrophy; cerebral small vessel diseases; cognition; computer-assisted; image processing; magnetic resonance imaging; stroke.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Atrophy / diagnosis
  • Atrophy / pathology*
  • Brain / pathology
  • Brain Injuries / pathology*
  • Cerebral Small Vessel Diseases / diagnosis
  • Cerebral Small Vessel Diseases / pathology*
  • Disease Progression
  • Female
  • Humans
  • Image Processing, Computer-Assisted* / methods
  • Magnetic Resonance Imaging / methods
  • Male
  • Middle Aged
  • Severity of Illness Index
  • Stroke / diagnosis
  • Stroke / pathology*