Resting cerebral blood flow alterations in chronic traumatic brain injury: an arterial spin labeling perfusion FMRI study.
Non-invasive measurement of resting state cerebral blood flow (CBF) may reflect alterations of brain structure and function after traumatic brain injury (TBI). However, previous imaging studies of resting state brain in chronic TBI have been limited by several factors, including measurement in relative rather than absolute units, use of crude spatial registration methods, exclusion of subjects with substantial focal lesions, and exposure to ionizing radiation, which limits repeated assessments. This study aimed to overcome those obstacles by measuring absolute CBF with an arterial spin labeling perfusion fMRI technique, and using an image preprocessing protocol that is optimized for brains with mixed diffuse and focal injuries characteristic of moderate and severe TBI. Resting state CBF was quantified in 27 individuals with moderate to severe TBI in the chronic stage, and 22 demographically matched healthy controls. In addition to global CBF reductions in the TBI subjects, more prominent regional hypoperfusion was found in the posterior cingulate cortices, the thalami, and multiple locations in the frontal cortices. Diffuse injury, as assessed by tensor-based morphometry, was mainly associated with reduced CBF in the posterior cingulate cortices and the thalami, where the greatest volume losses were detected. Hypoperfusion in superior and middle frontal cortices, in contrast, was associated with focal lesions. These results suggest that structural lesions, both focal and diffuse, are the main contributors to the absolute CBF alterations seen in chronic TBI, and that CBF may serve as a tool to assess functioning neuronal volume. We also speculate that resting reductions in posterior cingulate perfusion may reflect alterations in the default-mode network, and may contribute to the attentional deficits common in TBI.
Kim
Junghoon
J
Moss Rehabilitation Research Institute, Albert Einstein Healthcare Network, Elkins Park, Pennsylvania 19027, USA. kimj@einstein.edu
Whyte
John
J
Patel
Sunil
S
Avants
Brian
B
Europa
Eduardo
E
Wang
Jiongjiong
J
Slattery
John
J
Gee
James C
JC
Coslett
H Branch
HB
Detre
John A
JA
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000473:pathology; D001930:Brain Injuries / Q000473:pathology / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D002908:Chronic Disease; D056324:Diffusion Tensor Imaging; D005260:Female; D015600:Glasgow Coma Scale; D023261:Glasgow Outcome Scale; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D013113:Spin Labels; D055815:Young Adult
D013113:Spin Labels