Abstract
Introduction Many studies have reported on vulnerable areas
and neural tracts of the brain after hypoxic–ischemic brain
injury (HI-BI). However, little is known about injury of the
ascending reticular activating system (ARAS). We attempted
to investigate on injury of the lower portion of the ARAS in
patients with HI-BI using diffusion tensor tractography
(DTT).
Methods Fourteen consecutive patients with HI-BI and 10
control subjects were recruited for this study. We classified
the patients into two subgroups according to the preservation
of arousal: subgroup A (eight patients)—intact arousal and
subgroup B (six patients)—impaired arousal. The lower portion
of the ARAS between the pontine reticular formation and
the thalamus was reconstructed using the probabilistic
tractography method. Fractional anisotropy (FA), mean diffusivity
(MD), and tract volume (TV) were measured.
Results The FA value and TV were decreased in subgroup B
compared with those of the control group, although no difference
was observed in the MD value (p0.05).