Background and Purpose- We investigated the relationship between impaired consciousness and ascending reticular activating system (ARAS) characteristics on diffusion tensor tractography during the early stage of spontaneous intracerebral hemorrhage confined to a unilateral supratentorial area. Methods- A total of 29 consecutive patients with impaired consciousness (the patient group A), 31 age- and sex-matched patients without impaired consciousness (the patient group B), and 20 age- and sex-matched healthy control subjects were recruited. The Glasgow Coma Scale was used to evaluate patients' conscious state in the early stage of intracerebral hemorrhage (within 30 days after onset). Three parts of the ARAS (lower dorsal, lower ventral, and upper) were reconstructed, and fractional anisotropy and tract volume values were determined. Results- The tract volume value of the lower dorsal ARAS in the patient group A was significantly lower than those of the patient group B and control group in the affected hemisphere (P<0.05). Among the diffusion tensor tractography parameters, only the tract volume of the lower dorsal ARAS in the affected hemispheres of the patient group A had a moderate positive correlation with Glasgow Coma Scale score (r=0.456; P<0.05). Conclusions- Impaired consciousness during the early stage of intracerebral hemorrhage was closely related to injury of the lower dorsal ARAS in the affected hemisphere. Clinical Trial Registration- URL: http://www.e-irb.com/index.jsp. Unique identifier: 2015-07-064.
Keywords: Glasgow Coma Scale; consciousness; intracerebral hemorrhage.