Patients with chronic mild or moderate traumatic brain injury have abnormal brain enlargement

ABSTRACT

Introduction: Much less is known about brain volume abnormalities in patients with chronic mild or moderate traumatic brain injury (TBI) compared with patients with more severe injury. Commercially available software methods including NeuroQuant® are being used increasingly to assess MRI brain volume in patients with TBI.

Methods: 50 patients with mild or moderate TBI were compared to the NeuroQuant® normal control database (n = thousands) with respect to MRI brain volume.

Results: The patients had many areas of abnormal enlargement and fewer areas of atrophy, including abnormally small cerebral white matter (CWM) limited to the first 10 months after injury. Examination of correlations within the patient group between CWM volume and volumes of the abnormally enlarged regions showed multiple significant negative correlations, indicating that CWM atrophy correlated with enlargement of the other regions.

Discussion: The finding of many regions of abnormal brain enlargement was relatively new, although a couple of previous studies of patients with mild TBI found similar but more limited findings. The cause of the abnormal enlargement was unknown, but possibilities included: (1) hyperactivity and hypertrophy; or (2) chronic neuro-inflammation and edema.

Abbreviations: ADNI: Alzheimer’s Disease Neuroimaging Initiative; CWM: cerebral white matter; GM: cerebral cortical gray matter; ICC: intraclass correlations coefficient; IFT: infratentorial; MRI: magnetic resonance imaging; mTBI: mild TBI; NQ: NeuroQuant®; SCN: subcortical nuclei; t0: time of injury; t1: time of first NeuroQuanted MRI scan after injury; t2: time of second NeuroQuanted MRI scan after injury; TBI: traumatic brain injury; VBR: ventricle-to-brain ratio; WBP: whole-brain parenchyma.

KEYWORDS:

• Traumatic brain injury
• magnetic resonance imaging
• volumetry
• asymmetry

Declaration of interest statement

Dr. Ross is CEO of NeuroGage LLC, a company which produces Neurogage® software, which is based on NeuroQuant® (however, Neurogage® was not used in the current study). In 2017, Dr. Ross was a paid consultant for CorTechs Labs, Inc., which produces NeuroQuant® software. None of the other authors had competing interests.

Contributors

David Ross designed the study, carried out much of the work, and wrote most of this paper.

John Seabaugh assisted with scheduling MRI scans and analysis of MRI brain volume data.

Jan Seabaugh assisted with clinicial evaluations of patients.

Claudia Alvarez, Laura Peyton Ellis, Christopher Powell, Christopher Hall, Christopher Reese and Leah Cooper assisted with organization and analysis of research data.

Alfred Ochs helped write this paper, including understanding the results and integrating them into the broader literature.