title: Integrated imaging approach with MEG and DTI to detect mild traumatic brain injury in military and civilian patients.
abstract: Traumatic brain injury (TBI) is a leading cause of sustained impairment in military and civilian populations. However, mild (and some moderate) TBI can be difficult to diagnose due to lack of obvious external injuries and because the injuries are often not visible on conventional acute MRI or CT. Injured brain tissues in TBI patients generate pathological low-frequency neuronal magnetic signal (delta waves 1-4 Hz) that can be measured and localized by magnetoencephalography (MEG). We hypothesize that abnormal MEG delta waves originate from gray matter neurons that experience de-afferentation due to axonal injury to the underlying white matter fiber tracts, which is manifested on diffusion tensor imaging (DTI) as reduced fractional anisotropy. The present study used a neuroimaging approach integrating findings of magnetoencephalography (MEG) and diffusion tensor imaging (DTI), evaluating their utility in diagnosing mild TBI in 10 subjects in whom conventional CT and MRI showed no visible lesions in 9. The results show: (1) the integrated approach with MEG and DTI is more sensitive than conventional CT and MRI in detecting subtle neuronal injury in mild TBI; (2) MEG slow waves in mild TBI patients originate from cortical gray matter areas that experience de-afferentation due to axonal injuries in the white matter fibers with reduced fractional anisotropy; (3) findings from the integrated imaging approach are consistent with post-concussive symptoms; (4) in some cases, abnormal MEG delta waves were observed in subjects without obvious DTI abnormality, indicating that MEG may be more sensitive than DTI in diagnosing mild TBI.
authors.affiliation: Research, Radiology, Rehabilitation, and Psychiatry Services, VA San Diego Healthcare System, San Diego, California, USA. mxhuang@ucsd.edu
authors.forename: Ming-Xiong
authors.initials: MX
authors.lastname: Huang
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Theilmann
authors.forename: Ashley
authors.initials: A
authors.lastname: Robb
authors.forename: Annemarie
authors.initials: A
authors.lastname: Angeles
authors.forename: Sharon
authors.initials: S
authors.lastname: Nichols
authors.forename: Angela
authors.initials: A
authors.lastname: Drake
authors.forename: John
authors.initials: J
authors.lastname: D'Andrea
authors.forename: Michael
authors.initials: M
authors.lastname: Levy
authors.forename: Martin
authors.initials: M
authors.lastname: Holland
authors.forename: Tao
authors.initials: T
authors.lastname: Song
authors.forename: Sheng
authors.initials: S
authors.lastname: Ge
authors.forename: Eric
authors.initials: E
authors.lastname: Hwang
authors.forename: Kevin
authors.initials: K
authors.lastname: Yoo
authors.forename: Li
authors.initials: L
authors.lastname: Cui
authors.forename: Dewleen G
authors.initials: DG
authors.lastname: Baker
authors.forename: Doris
authors.initials: D
authors.lastname: Trauner
authors.forename: Raul
authors.initials: R
authors.lastname: Coimbra
authors.forename: Roland R
authors.initials: RR
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D016880:Anisotropy; D001753:Blast Injuries / Q000175:diagnosis*; D001921:Brain / Q000473:pathology*; D001930:Brain Injuries / Q000175:diagnosis*; D001931:Brain Mapping; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015601:Injury Severity Score; D015225:Magnetoencephalography; D008297:Male; D008889:Military Personnel; D018579:Patient Selection