Optic radiation injury in patients with aneurismal subarachnoid hemorrhage: a preliminary diffusion tensor imaging report

Visual field defect is one of the various clinical manifestations in patients with subarachnoid hemorrhage（SAH）. Little is known about the pathogenic mechanism of visual field defect in SAH. In the current study,we investigated the diffusion tensor imaging （DTI） finding of the optic radiation in patients with SAH followingrupture of a cerebral artery aneurysm. We recruited 21 patients with aneurismal SAH （12 males, 9 females, mean age, 52.67 years; range, 41–68 years） who showed no definite lesion along the visual pathway.Twenty-one age-and sex-matched normal control subjects were also recruited. DTI data were acquired at an average of 5.9 weeks （range： 3–12 weeks） after onset and reconstruction of the optic radiation was performed using DTI-Studio software. The fractional anisotropy value, apparent diffusion coefficient value,and fiber number of the optic radiation were measured. The fractional anisotropy value of the optic radiation was significantly decreased, and the apparent diffusion coefficient value was significantly increased, in patients with aneurismal SAH than in normal control subjects. However, there was no significant difference in the fiber number of the optic radiation between patients with aneurismal SAH and normal control subjects. The decrement of fractional anisotropy value and increment of apparent diffusion coefficient value of the optic radiation in patients with aneurismal SAH suggest optic radiation injury. Therefore, we recommend a thorough evaluation for optic radiation injury in patient with aneurismal SAH.

Is thalamocortical tract injury responsible for memory impairment in a patient with putaminal hemorrhage?

Prior to development of diffusion tensor imaging （DTI）, there were many difficulties in visualization and estimation of the Papez circuit in the live human brain （Papez, 1995）. Diffusion tensor tractography （DTT）, derived from DTI, allows for identification and visualization of neural tracts in the Papez circuit （Concha et al., 2005; Kwon et al., 2010; Granziera et al., 2011; Jang and Yeo, 2013; Jang et al., 2014a）. In the current study, using DTT, we report on a patient who showed injured thalamocortical tract between the anterior thalamic nuclei and the cingulate gyrus following a putaminal hemorrhage.

Reorganization of injured anterior cingulums in a hemorrhagic stroke patient

In this study, we reported on a patient who showed a new neural tract between the injured anterior cingu- lums and the basal forebrain, as shown by diffusion tensor tractography （DTT）.

Neglected corticospinal tract injury for 10 months in a stroke patient

The corticospinal tract（CST）is an essential motor pathway in the human brain：particularly,it is essential for fine hand movements（Jang,2014）.Stroke patients can show more severe weakness when a partial injury of the CST is combined with apraxia.