Many studies have reported about injury of the ascending reticular activating system (ARAS) in patients with various brain pathologies, using diffusion tensor tractography (DTT); however, little is known about injury of the ARAS in patients with pontine hemorrhage. In this study, using DTT, we attempted to investigate injury of the lower ventral and dorsal ARAS in patients with pontine hemorrhage. Twenty-three consecutive patients with pontine hemorrhage and 14 control subjects were recruited into this study. The patients were classified into 2 subgroups on the basis of the preservation of arousal: subgroup A (14 patients)-intact arousal, subgroup B (9 patients)-impaired arousal. The lower ventral and dorsal ARAS between the pontine reticular formation with hypothalamus and thalamic intralaminar nucleus were reconstructed. Fractional anisotropy (FA), mean diffusivity (MD), and tract volume (TV) values were measured. The TVs of the lower ventral and dorsal ARAS were significantly lower in subgroup B than in the subgroup A and control group (P < 0.05). In terms of FA value, the lower dorsal ARAS were significantly lower in subgroup A and subgroup B than in the control group (P < 0.05). In conclusion, injury of the lower ventral and dorsal ARAS was demonstrated in patients with impaired arousal following pontine hemorrhage. We believe that analysis of the ARAS using DTT would be helpful in evaluation of patients with impaired consciousness after pontine hemorrhage.

Pusher syndrome is a disorder of postural control. It is associated with unilateral lesions on central vestibular system. In the current study, we attempted to identify and investigate neural connectivity of the parieto-insular vestibular cortex in a patient with pusher syndrome, using diffusion tensor imaging.

Prognosis predictability of the nigrostriatal tract (NST) and corticoreticulospinal tract (CRT) of affected hemisphere at early stage for gait function at chronic stage were investigated using diffusion tensor tractography (DTT) in patients with a cerebral infarction. Thirty consecutive patients with middle cerebral artery (MCA) territory infarction were recruited. Functional ambulation category (FAC) was used to evaluate the gait function at chronic stage. Fractional anisotropy (FA) and tract volume (TV) of ipsilesional NST and ipsilesional CRT were determined to be DTT parameters at early stage. FAC score at chronic stage showed strong positive correlations with TVs of ipsilesional NST and ipsilesional CRT at early stage (ipsilesional NST R = 0.786; ipsilesional CRT R = 0.821; P < .05). According to regression model, FAC score at chronic stage was positively related to TVs of ipsilesional NST and ipsilesional CRT at early stage (Adjusted R2 = 0.700, F = 34.905, P < .05). FAC score at chronic stage was associated more positively with TV of ipsilesional CRT (β = 0.532) than that of ipsilesional NST (β = 0.362). Ipsilesional NST and ipsilesional CRT at early stage had prognosis predictability for gait function at chronic stage in patients with an MCA infarction. Moreover, ipsilesional CRT had stronger predictability than ipsilesional NST.

Central vestibular disorder is common after middle cerebral artery (MCA) territory infarction. The MCA supplies blood to the parieto-insular vestibular cortex (PIVC), a core region of central vestibular symptoms. We report on patients that sustained injuries of the core vestibular pathway to the PIVC with central vestibular disorder following MCA territory infarction, demonstrated on diffusion tensor imaging (DTI). Nineteen patients with MCA territory infarction and 12 control subjects were recruited. To reconstruct the core vestibular pathway to the PIVC, we defined seed region of interest (ROI) as vestibular nuclei of pons and target ROI as the PIVC. Fractional anisotropy (FA), mean diffusivity, and tract volume were measured. In the affected hemisphere, FA value of the core vestibular pathway to the PIVC revealed significant difference between all patient groups and the control group (P < .05). In contrast, patients with symptoms of ataxia only revealed significant decrement of tract volume compared with the control group (P < .05). Additionally, subgroup B revealed significant decrement of tract volume compared with that of subgroup A and the control group (P < .05). In the unaffected hemisphere, there was no significant difference in all DTI parameters between all patient groups and the control group (P < .05). Injury to the core vestibular pathway to the PIVC was demonstrated in patients that revealed typical central vestibular disorder following MCA territory infarction. Analysis of the core vestibular pathway to the PIVC using DTI would be beneficial in clinical evaluation and management of patients with MCA territory infarction.

We report on a patient with mild traumatic brain injury (TBI) with contrecoup injury of the prefronto-thalamic tract (PTT), as demonstrated by diffusion tensor tractography (DTT).

Lateral medullary syndrome is a central vestibular disorder characterized by vertigo and ataxia. We report on a patient with injury of the lateral vestibulospinal tract (VST) following lateral medullary syndrome, detected on diffusion tensor tractography (DTT).

We investigated differences in corpus callosum (CC) injuries between patients with concussion and those with diffuse axonal injury (DAI) by using diffusion tensor tractography (DTT).

We report a stroke patient who showed increased thalamocortical connectivity to the medial prefrontal cortex (mPFC) with recovery of impaired consciousness that was demonstrated on diffusion tensor tractography (DTT) of the ascending reticular activating system (ARAS).

The prefrontothalamic tract (PTT) injury is associated with various neuropsychological impairments including cognitive impairment. We report on three women with hemorrhagic stroke who showed changes in the PTT following cranioplasty (C/P) using diffusion tensor tractography (DTT) images.

Many studies using diffusion tensor imaging (DTI) have demonstrated traumatic axonal injury (TAI) in patients whose conventional brain magnetic resonance imaging (MRI) results are negative following head trauma. Injury mechanism for TAI in these patients has been mainly associated with motor vehicle accident, whereas very little is known about TAI by violence.

We report on restoration of the ascending reticular activating system (ARAS), compressed by an intracerebral hematoma and perihematomal edema following a stroke. The restoration of the ARAS was demonstrated by diffusion tensor tractography (DTT).

We report on a patient with traumatic brain injury who showed motor recovery concurrent with recovery of injured corticofugal tracts (CFTs), diagnosed by diffusion tensor tractography (DTT).

We report on a patient whose arcuate fasciculus (AF) and corticobulbar tract (CBT) recovered following an infarct in the middle cerebral artery (MCA) territory, demonstrated on serial diffusion tensor tractography (DTT).

We report on a patient who developed limb-kinetic apraxia (LKA) due to an injured corticofugal tract (CFT) from the secondary motor area following mild traumatic brain injury (TBI), demonstrated on diffusion tensor tractography (DTT).

Little is known about optic radiation (OR) injury following aneurysmal subarachnoid hemorrhage (SAH). In the current study, we report on a patient who showed a visual field defect and injury of the OR following aneurysmal SAH, using diffusion tensor tractography (DTT).

The cortico-ponto-cerebellar tract (CPCT) is involved in coordination of movement; injury of the CPCT can therefore be accompanied by ataxia. In this study, using diffusion tensor tractography (DTT), we investigated injury of the CPCT in patients with mild traumatic brain injury (TBI).

Limb-kinetic apraxia (LKA) is a disorder of movement execution that is a result of injury to the corticofugal tracts (CFTs) from the secondary motor area. We report on a patient with traumatic brain injury (TBI) and complete monoplegia due to LKA, which was mainly ascribed to injury of the CFT from the secondary motor area using diffusion tensor tractography.

The aim of this study was to investigate changes of synaptic area of the spinothalamic tract and its thalamocortical pathway (STT) in the thalamus in chronic patients with putaminal hemorrhage.Twenty four patients with a lesion in the ventral posterior lateral nucleus (VPL) of the thalamus following putaminal hemorrhage were recruited for this study. The subscale for tactile sensation of the Nottingham Sensory Assessment (NSA) was used for the determination of somatosensory function. Diffusion tensor tractography of the STT was reconstructed using the Functional Magnetic Resonance Imaging of the Brain Software Library. We classified patients according to 2 groups: the VPL group, patients whose STTs were synapsed in the VPL; and the non-VPL group, patients whose STTs were synapsed in other thalamic areas, except for the VPL.Thirteen patients belonged to the VPL group, and 8 patients belonged to the non-VPL group. Three patients were excluded from grouping due to interrupted integrity of the STTs. The tactile sensation score of the NSA in the non-VPL group (10.50 ± 0.93) was significantly decreased compared with that of the VPL group (19.45 ± 1.33) (P < 0.05).We found that 2 types of patient had recovered via the VPL area or other areas of the STT. It appears that patients who showed shifting of the thalamic synaptic area of the STT might have recovered by the process of thalamic reorganization following thalamic injury. In addition, thalamic reorganization appears to be related to poorer somatosensory outcome.

We investigated the change of the corticospinal tract (CST) in the unaffected hemisphere by the change of the dominant hand in stroke patients, using diffusion tensor tractography (DTT).Forty-eight stroke patients with right-hand dominance were recruited. The patients were assigned to 3 groups: group A (12 patients)-right-hand dominance was maintained after the right-hand weakness, group B (17 patients)-right-hand dominance changed to the left-hand dominance after the right-hand weakness, and group C (19 patients)-right-hand dominance was maintained after the left-hand weakness had developed. The function of the unaffected upper extremity was evaluated using the grip strength (GS), Manual Function Test (MFT), Purdue Pegboard Test (PPT), and modified Barthel Index (MBI). DTT was performed twice (1st DTT, 2nd DTT), and the fractional anisotropy (FA), apparent diffusion coefficient (ADC), and voxel number (VN) of the CST in the unaffected hemisphere were measured.In group B, the VN on 2nd DTT was significantly increased compared with the 1st DTT, and all other clinical data (GS, MFT, PPT, and MBI) showed a significant increase between 1st and 2nd DTT (P < 0.05). The change of the VN showed moderate correlation with the change of the GS (r = 0.499, P < 0.05), PPT (r = 0.531, P < 0.05), and MBI (r = 0.551, P < 0.05).We found that the fiber number of the CST in the unaffected hemisphere was increased by the change of the dominant hand in stroke patients. We believe that our results have important implications in terms of neurorehabilitation.

The periaqueductal gray (PAG) plays a pivotal role in pain modulation. We attempted to examine the relation between injury of the PAG and central pain in patients with mild traumatic brain injury (TBI).Sixty-one patients with mild TBI with central pain and 31 healthy control subjects were recruited for this study. Visual analog scale (VAS) was used for evaluation of central pain. The region of interest was defined for the PAG and the fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were measured.The FA value was significantly lower in the patient group than in the control group (P < 0.05). However, no significant difference in the ADC value was observed between the patient and control groups (P > 0.05). VAS score of the patient group showed significant moderate negative correlation with the FA (r = -0.38), while no significant correlation was observed between VAS score and the ADC value (P < 0.05).We demonstrated injury of the PAG in patients with central pain following mild TBI and the degree of injury of the PAG was closely related to the degree of central pain.