The usefulness of diffusion tensor imaging in detection of diffuse axonal injury in a patient with head trauma

Diffuse axonal injury is the predominant mechanism of injuries in patients with traumatic brain injury. Neither conventional brain computed tomography nor magnetic resonance imaging has shown sufficient sensitivity in the diagnosis of diffuse axonal injury. In the current study, we attempted to demonstrate the usefulness of diffusion tensor imaging in the detection of lesion sites of diffuse axonal injury in a patient with head trauma who had been misdiagnosed as having a stroke. A 44-year-old man fell from a height of about 2 m. Brain magnetic resonance imaging (32 months after onset) showed leukomalactic lesions in the isthmus of the corpus callosum and the left temporal lobe. He presented with mild quadriparesis, intentional tremor of both hands, and trunkal ataxia. From diffusion tensor imaging results of 33 months after traumatic brain injury onset, we found diffuse axonal injury in the right corticospinal tract (centrum semiovale, pons), both fornices (columns and crus), and both inferior cerebellar peduncles (cerebellar portions). We think that diffusion tensor imaging could be a useful tool in the detection of lesion sites of diffuse axonal injury in patients with head trauma.     

Feasibility of 3.0 T diffusion-weighted nuclear magnetic resonance imaging in the evaluation of functional recovery of rats with complete spinal cord injury

Diffusion tensor imaging is a sensitive way to reflect axonal necrosis and degeneration, glial cell regeneration and demyelination following spinal cord injury, and to display microstructure changes in the spinal cord in vivo. Diffusion tensor imaging technology is a sensitive method to diagnose spinal cord injury; fiber tractography visualizes the white matter fibers, and directly displays the structural integrity and resultant damage of the fiber bundle. At present, diffusion tensor imaging is restricted to brain examinations, and is rarely applied in the evaluation of spinal cord injury. This study aimed to explore the fractional anisotropy and apparent diffusion coefficient of diffusion tensor magnetic resonance imaging and the feasibility of diffusion tensor tractography in the evaluation of complete spinal cord injury in rats. The results showed that the average combined scores were obviously decreased after spinal cord transection in rats, and then began to increase over time. The fractional anisotropy scores after spinal cord transection in rats were significantly lower than those in normal rats(P 0.05); the apparent diffusion coefficient was significantly increased compared with the normal group(P 0.05). Following spinal cord transection, fractional anisotropy scores were negatively correlated with apparent diffusion coefficient values(r = –0.856, P 0.01), and positively correlated with the average combined scores(r = 0.943, P 0.01), while apparent diffusion coefficient values had a negative correlation with the average combined scores(r = –0.949, P 0.01). Experimental findings suggest that, as a non-invasive examination, diffusion tensor magnetic resonance imaging can provide qualitative and quantitative information about spinal cord injury. The fractional anisotropy score and apparent diffusion coefficient have a good correlation with the average combined scores, which reflect functional recovery after spinal cord injury.     

重型颅脑损伤患者亚低温治疗的临床研究

Objective To compare the prognoses of patients with severe brain injury receiving mild hypothermia and normothermia interventions and evaluate the brain protective effect of mild hypothermia. Methods Seventy-six patients with severe head injury (Glaseow Coma Score≤8) were divided into mild hypothermia group (36 cases) and normothermia group (40 cases). The patients in the normothermia group were managed with measures for reducing the intracranial pressure and controlling the hemorrhage and gastric acid, with also administration of neurotrophic treatment and nutritional support. In addition to these conventional interventions, the patients in mild hypothermia group received mild hypothermia treatment administered using a water blanket to reduce the core body temperature and brain temperature to 32-34℃, which was maintained for 3-14 days as needed. Results The patients receiving mild hypothermia therapy had significantly improved prognosis in comparison with those in normothermia group (P<0.05). Conclusion Mild hypothermia treatment has brain protective effect and improves the prognosis of patients with severe brain injury.     

重型颅脑损伤患者亚低温治疗的临床研究

Objective To compare the prognoses of patients with severe brain injury receiving mild hypothermia and normothermia interventions and evaluate the brain protective effect of mild hypothermia. Methods Seventy-six patients with severe head injury (Glaseow Coma Score≤8) were divided into mild hypothermia group (36 cases) and normothermia group (40 cases). The patients in the normothermia group were managed with measures for reducing the intracranial pressure and controlling the hemorrhage and gastric acid, with also administration of neurotrophic treatment and nutritional support. In addition to these conventional interventions, the patients in mild hypothermia group received mild hypothermia treatment administered using a water blanket to reduce the core body temperature and brain temperature to 32-34℃, which was maintained for 3-14 days as needed. Results The patients receiving mild hypothermia therapy had significantly improved prognosis in comparison with those in normothermia group (P<0.05). Conclusion Mild hypothermia treatment has brain protective effect and improves the prognosis of patients with severe brain injury.     

重型颅脑损伤患者亚低温治疗的临床研究

Objective To compare the prognoses of patients with severe brain injury receiving mild hypothermia and normothermia interventions and evaluate the brain protective effect of mild hypothermia. Methods Seventy-six patients with severe head injury (Glaseow Coma Score≤8) were divided into mild hypothermia group (36 cases) and normothermia group (40 cases). The patients in the normothermia group were managed with measures for reducing the intracranial pressure and controlling the hemorrhage and gastric acid, with also administration of neurotrophic treatment and nutritional support. In addition to these conventional interventions, the patients in mild hypothermia group received mild hypothermia treatment administered using a water blanket to reduce the core body temperature and brain temperature to 32-34℃, which was maintained for 3-14 days as needed. Results The patients receiving mild hypothermia therapy had significantly improved prognosis in comparison with those in normothermia group (P<0.05). Conclusion Mild hypothermia treatment has brain protective effect and improves the prognosis of patients with severe brain injury.     

重型颅脑损伤患者亚低温治疗的临床研究

Objective To compare the prognoses of patients with severe brain injury receiving mild hypothermia and normothermia interventions and evaluate the brain protective effect of mild hypothermia. Methods Seventy-six patients with severe head injury (Glaseow Coma Score≤8) were divided into mild hypothermia group (36 cases) and normothermia group (40 cases). The patients in the normothermia group were managed with measures for reducing the intracranial pressure and controlling the hemorrhage and gastric acid, with also administration of neurotrophic treatment and nutritional support. In addition to these conventional interventions, the patients in mild hypothermia group received mild hypothermia treatment administered using a water blanket to reduce the core body temperature and brain temperature to 32-34℃, which was maintained for 3-14 days as needed. Results The patients receiving mild hypothermia therapy had significantly improved prognosis in comparison with those in normothermia group (P<0.05). Conclusion Mild hypothermia treatment has brain protective effect and improves the prognosis of patients with severe brain injury.     

重型颅脑损伤患者亚低温治疗的临床研究

Objective To compare the prognoses of patients with severe brain injury receiving mild hypothermia and normothermia interventions and evaluate the brain protective effect of mild hypothermia. Methods Seventy-six patients with severe head injury (Glaseow Coma Score≤8) were divided into mild hypothermia group (36 cases) and normothermia group (40 cases). The patients in the normothermia group were managed with measures for reducing the intracranial pressure and controlling the hemorrhage and gastric acid, with also administration of neurotrophic treatment and nutritional support. In addition to these conventional interventions, the patients in mild hypothermia group received mild hypothermia treatment administered using a water blanket to reduce the core body temperature and brain temperature to 32-34℃, which was maintained for 3-14 days as needed. Results The patients receiving mild hypothermia therapy had significantly improved prognosis in comparison with those in normothermia group (P<0.05). Conclusion Mild hypothermia treatment has brain protective effect and improves the prognosis of patients with severe brain injury.     

重型颅脑损伤患者亚低温治疗的临床研究

Objective To compare the prognoses of patients with severe brain injury receiving mild hypothermia and normothermia interventions and evaluate the brain protective effect of mild hypothermia. Methods Seventy-six patients with severe head injury (Glaseow Coma Score≤8) were divided into mild hypothermia group (36 cases) and normothermia group (40 cases). The patients in the normothermia group were managed with measures for reducing the intracranial pressure and controlling the hemorrhage and gastric acid, with also administration of neurotrophic treatment and nutritional support. In addition to these conventional interventions, the patients in mild hypothermia group received mild hypothermia treatment administered using a water blanket to reduce the core body temperature and brain temperature to 32-34℃, which was maintained for 3-14 days as needed. Results The patients receiving mild hypothermia therapy had significantly improved prognosis in comparison with those in normothermia group (P<0.05). Conclusion Mild hypothermia treatment has brain protective effect and improves the prognosis of patients with severe brain injury.     

重型颅脑损伤患者亚低温治疗的临床研究

Objective To compare the prognoses of patients with severe brain injury receiving mild hypothermia and normothermia interventions and evaluate the brain protective effect of mild hypothermia. Methods Seventy-six patients with severe head injury (Glaseow Coma Score≤8) were divided into mild hypothermia group (36 cases) and normothermia group (40 cases). The patients in the normothermia group were managed with measures for reducing the intracranial pressure and controlling the hemorrhage and gastric acid, with also administration of neurotrophic treatment and nutritional support. In addition to these conventional interventions, the patients in mild hypothermia group received mild hypothermia treatment administered using a water blanket to reduce the core body temperature and brain temperature to 32-34℃, which was maintained for 3-14 days as needed. Results The patients receiving mild hypothermia therapy had significantly improved prognosis in comparison with those in normothermia group (P<0.05). Conclusion Mild hypothermia treatment has brain protective effect and improves the prognosis of patients with severe brain injury.     

重型颅脑损伤患者亚低温治疗的临床研究

Objective To compare the prognoses of patients with severe brain injury receiving mild hypothermia and normothermia interventions and evaluate the brain protective effect of mild hypothermia. Methods Seventy-six patients with severe head injury (Glaseow Coma Score≤8) were divided into mild hypothermia group (36 cases) and normothermia group (40 cases). The patients in the normothermia group were managed with measures for reducing the intracranial pressure and controlling the hemorrhage and gastric acid, with also administration of neurotrophic treatment and nutritional support. In addition to these conventional interventions, the patients in mild hypothermia group received mild hypothermia treatment administered using a water blanket to reduce the core body temperature and brain temperature to 32-34℃, which was maintained for 3-14 days as needed. Results The patients receiving mild hypothermia therapy had significantly improved prognosis in comparison with those in normothermia group (P<0.05). Conclusion Mild hypothermia treatment has brain protective effect and improves the prognosis of patients with severe brain injury.     

Why do stroke patients with negative motor evoked potential show poor limb motor function recovery？

Negative motor evoked potentials after cerebral infarction, indicative of poor recovery of limb motor function, tend to be accompanied by changes in fractional anisotropy values and the cerebral pe-duncle area on the affected side, but the characteristics of these changes have not been reported. This study included 57 cases of cerebral infarction whose motor evoked potentials were tested in the 24 hours after the first inspection for diffusion tensor imaging, in which 29 cases were in the negative group and 28 cases in the positive group. Twenty-nine patients with negative motor evoked potentials were divided into two groups according to fractional anisotropy on the affected side of the cerebral peduncle： a fractional anisotropy 〈 0.36 group and a fractional anisotropy 〉 0.36 group. All patients underwent a regular magnetic resonance imaging and a diffusion tensor imaging examina- tion at 1 week, 1, 3, 6 and 12 months after cerebral infarction. The FugI-Meyer scores of their hemiplegic limbs were tested before the magnetic resonance and diffusion tensor imaging exami-nations. In the negative motor evoked potential group, fractional anisotropy in the affected cerebral peduncle declined progressively, which was most obvious in the first 1-3 months after the onset of cerebral infarction. The areas and area asymmetries of the cerebral peduncle on the affected side were significantly decreased at 6 and 12 months after onset. At 12 months after onset, the area asymmetries of the cerebral peduncle on the affected side were lower than the normal lower limit value of 0.83. FugI-Meyer scores in the fractional anisotropy ≥0.36 group were significantly higher than in the fractional anisotropy 〈 0.36 group at 3-12 months after onset. The fractional anisotropy of the cerebral peduncle in the positive motor evoked potential group decreased in the first 1 month after onset, and stayed unchanged from 3-12 months; there was no change in the area of the cerebral peduncle in the first 1-12 months after cerebral infarction. These findings confirmed that if the fractional anisotropy of the cerebral peduncle on the affected side is 〈 0.36 and the area asym-metries 〈 0.83 in patients with negative motor evoked potential after cerebral infarction, then poor hemiplegic limb motor function recovery may occur.     

Mild hypothermia combined with a scaffold of NgR- silenced neural stem cells/Schwann cells to treat spinal cord injury

Because the inhibition of Nogo proteins can promote neurite growth and nerve cell differentiation, a cell-scaffold complex seeded with Nogo receptor(Ng R)-silenced neural stem cells and Schwann cells may be able to improve the microenvironment for spinal cord injury repair. Previous studies have found that mild hypothermia helps to attenuate secondary damage in the spinal cord and exerts a neuroprotective effect. Here, we constructed a cell-scaffold complex consisting of a poly(D,L-lactide-co-glycolic acid)(PLGA) scaffold seeded with Ng R-silenced neural stem cells and Schwann cells, and determined the effects of mild hypothermia combined with the cell-scaffold complexes on the spinal cord hemi-transection injury in the T9 segment in rats. Compared with the PLGA group and the Ng R-silencing cells + PLGA group, hindlimb motor function and nerve electrophysiological function were clearly improved, pathological changes in the injured spinal cord were attenuated, and the number of surviving cells and nerve fibers were increased in the group treated with the Ng R-silenced cell scaffold + mild hypothermia at 34°C for 6 hours. Furthermore, fewer pathological changes to the injured spinal cord and more surviving cells and nerve fibers were found after mild hypothermia therapy than in injuries not treated with mild hypothermia. These experimental results indicate that mild hypothermia combined with Ng R gene-silenced cells in a PLGA scaffold may be an effective therapy for treating spinal cord injury.     

DTI and pathological changes in a rabbit model of radiation injury to the spinal cord after ~(125)I radioactive seed implantation

Excessive radiation exposure may lead to edema of the spinal cord and deterioration of the nervous system. Magnetic resonance imaging can be used to judge and assess the extent of edema and to evaluate pathological changes and thus may be used for the evaluation of spinal cord injuries caused by radiation therapy. Radioactive ~(125)I seeds to irradiate 90% of the spinal cord tissue at doses of 40–100 Gy(D90) were implanted in rabbits at T_(10) to induce radiation injury, and we evaluated their safety for use in the spinal cord. Diffusion tensor imaging showed that with increased D90, the apparent diffusion coefficient and fractional anisotropy values were increased. Moreover, pathological damage of neurons and microvessels in the gray matter and white matter was aggravated. At 2 months after implantation, obvious pathological injury was visible in the spinal cords of each group. Magnetic resonance diffusion tensor imaging revealed the radiation injury to the spinal cord, and we quantified the degree of spinal cord injury through apparent diffusion coefficient and fractional anisotropy.     

Diffusion tensor tractography characteristics of axonal injury in concussion/mild traumatic brain injury

The main advantage of diffusion tensor tractography is that it allows the entire neural tract to be evaluated.In addition,configurational analysis of reconstructed neural tracts can indicate abnormalities such as tearing,narrowing,or discontinuations,which have been used to identify axonal injury of neural tracts in concussion patients.This review focuses on the characteristic features of axonal injury in concussion or mild traumatic brain injury(m TBI)patients through the use of diffusion tensor tractography.Axonal injury in concussion(m TBI)patients is characterized by their occurrence in long neural tracts and multiple injuries,and these characteristics are common in patients with diffuse axonal injury and in concussion(m TBI)patients with axonal injury.However,the discontinuation of the corticospinal tract is mostly observed in diffuse axonal injury,and partial tearing and narrowing in the subcortical white matter are frequently observed in concussion(m TBI)patients with axonal injury.This difference appears to be attributed to the observation that axonal injury in concussion(m TBI)patients is the result of weaker forces than those producing diffuse axonal injuries.In addition,regarding the fornix,in diffuse axonal injury,discontinuation of the fornical crus has been frequently reported,but in concussion(m TBI)patients,many collateral branches form in the fornix in addition to these findings in many case studies.It is presumed that the impact on the brain in TBI is relatively weaker than that in diffuse axonal injury,and that the formation of collateral branches occurs during the fornix recovery process.Although the occurrence of axonal injury in multiple areas of the brain is an important feature of diffuse axonal injury,case studies in concussion(m TBI)have shown that axonal injury occurs in multiple neural tracts.Because axonal injury lesions in m TBI patients may persist for approximately 10 years after injury onset,the characteristics of axonal injury in concussion(m TBI)patients,which are reviewed and categorized in this review,are expected to serve as useful supplementary information in the diagnosis of axonal injury in concussion(m TBI)patients.     

Imaging changes in neural circuits in patients with depression using 1 H-magnetic resonance spectroscopy and diffusion tensor imaging

1 H-magnetic resonance spectroscopy imaging and diffusion tensor imaging were performed in 19 patients with mild depression and in 13 controls.The mean age of the patients was 31 years.The mean Hamilton depression score of the patients was 22.5±13.2.N-acetylaspartate,choline and creatine concentrations and the average diffusion coefficient and fractional anisotropy values were measured in the bilateral hippocampus,striatum,thalamus and prefrontal deep white matter. Compared with the control group,the mild depressed patients had:(1)a higher choline/creatine ratio and a negative correlation between the choline/creatine ratio and the average diffusion coefficient in the hippocampus;(2)a lower choline/creatine ratio and a higher fractional anisotropy in the striatum;(3)a lower fractional anisotropy and a positive correlation between the fractional anisotropy and the choline/creatine ratio in the prefrontal deep white matter;and(4)a higher average diffusion coefficient and a positive correlation between the choline/creatine ratio and the N-acetylaspartate/creatine ratio in the thalamus,as well as positive correlation between the choline/creatine ratio and Hamilton depression scores.These data suggest evidence of abnormal connectivity in neurofibrotic microstructures and abnormal metabolic alterations in the limbic-cortical-striatal-pallidal-thalamic neural circuit in patients with mild depression.     

Effects of mild hypothermia on the expression of microtubule-associated protein 2 in neurons of the hippocampal dentate gyrus in a rat model of cerebral ischemia/reperfusion

BACKGROUND： It is widely accepted that mild hypothermia can protect against injury to cerebral ischemia/reperfusion. OBJECTIVE： To observe the effects of mild hypothermia on microtubule-associated protein 2 （MAP2） expression in the hippocampal dentate gyms in rats following cerebral ischemia/reperfusion. Also, to study neuronal ultrastmctural changes in the dentate gyms to investigate the mechanism of the protection against injury to cerebral ischemia/reperfusion conferred by mild hypothermia. DESIGN, TIME AND SETTING： This randomized grouping, neural cell morphology trial was performed at the Laboratory Animal Center of Yijishan Hospital between March and June 2007. MATERIALS： Eighty-five healthy male Sprague Dawley rats were randomly allocated to three groups： mild hypothermia （n = 40）, normothermia （n = 40）, and sham-operated （n = 5）. METHODS： Cerebral ischemia/reperfusion injury was induced by the suture method in the mild hypothermia and normothermia groups, with a threading depth of 180.5 mm. In the sham-operated group, the suture was inserted 15 mm, with no vascular ligafion, and was followed by reperfusion 2 hours later. In the sham-operated and normothermia groups, the rat rectal temperature was maintained at 36-37 ℃ ; in the mild hypothermia group, it was controlled at 32-33 ℃. MAIN OUTCOME MEASURES： The hippocampal dentate gyms was serially sectioned for hematoxylin-eosin staining and MAP2 immunohistochemistry. Ultrastructural changes and the MAP2 absorbance value of the hippocampal dentate gyms were examined by transmission electron microscopy. RESULTS： The sham-operated group exhibited approximately normal ultrastructure of neurons in the bilateral hippocampal dentate gyms. In the normothermia group, ischemic hippocampal dentate gyms neurons were found with markedly fewer normal mitochondria, greatly proliferated rough endoplasmic reticulum, and a swollen and dysmorphic Golgi. In the mild hypothermia group, at each corresponding time point, these abnormal changes w     

亚低温条件下弥漫性脑损伤海马区凋亡蛋白酶激活因子1蛋白的表达

The influence of mild hypothermia on neural cell apoptosis remains poorly understood. Therefore, the present study established rat models of diffuse axonal injury (DAI) at 33 ℃. Morris water maze results demonstrated significantly better learning and memory functions in DAI rats with hypothermia compared with DAI rats with normothermia. Expression of apoptotic protease activating factor-1 in the hippocampal CA1 region was significantly lower in the DAI hypothermia group compared with the DAI normothermia group. Expression of apoptotic protease activating factor-1 positively correlated with latency, but negatively correlated with platform location times and time of swimming in the quadrant area. Results suggested that post-traumatic mild hypothermia in a rat model of DAI could provide cerebral protection by attenuating expression of apoptotic protease activating factor-1.     

Photosensitivity as a symptom of maladapive plasticity in a patient with traumatic brain injury: Diffusion tensor imaging study

We report on a patient with traumatic brain injury who had photosensitivity as the presenting visual symptom and demonstrated axonal injury of the left optic radiation using diffusion tensor imaging. A 41-year-old man with traumatic brain injury began to complain of photosensitivity about 4 months after head trauma. The ophthalmic evaluation, including visual evoked potential study and conventional brain MRI, did not exhibit a pathologic basis for his photosensitivity. However, we did detect axonal injury in the left optic radiation on a diffusion tensor imaging study 36 months after onset. This lesion was almost recovered on 76-month diffusion tensor imaging study, however, the photosensitivity had continued. We suggest that the photosensitivity in this patient was caused by axonal injury of the left optic radiation and it seems to be a symptom of maladaptive plasticity that occurs during the recovery of the axonal injury of the left optic radiation.     

Diffusion tensor imaging assesses white matter injury in neonates with hypoxic-ischemic encephalopathy

With improvements in care of at-risk neonates, more and more children survive. This makes it increasingly important to assess, soon after birth, the prognosis of children with hypoxic-ischemic encephalopathy. Computed tomography, ultrasound, and conventional magnetic resonance imaging are helpful to diagnose brain injury, but cannot quantify white matter damage. In this study, ten full-term infants without brain injury and twenty-two full-term neonates with hypoxic-ischemic encephalopathy (14 moderate cases and 8 severe cases) underwent diffusion tensor imaging to assess its feasibility in evaluating white matter damage in this condition. Results demonstrated that fractional anisotropy, voxel volume, and number of fiber bundles were different in some brain areas between infants with brain injury and those without brain injury. The correlation between fractional anisotropy values and neonatal behavioral neurological assessment scores was closest in the posterior limbs of the internal capsule. We conclude that diffusion tensor imaging can quantify white matter injury in neonates with hypoxic-ischemic encephalopathy.     

Dynamic changes in cerebral microcirculation and hypoxia in the early stages of diffuse axonal injury

This study demonstrated that damage to the cerebral microvasculature,the formation of microthrombi and swelling of vascular endothelial cells occur early and peak 12 hours after injury in a rat model of diffuse axonal injury.Moreover,these pathological changes were most evident in the cerebral cortex.Cerebral microcirculatory dysfunction peaked later and had a shorter duration than axonal injury.In addition,the radioactive imaging agent,99Tcm-4,9-diaza-2,3,10,10-tetramethyldodecan-2,11-dione dioxime,was used to visualize the dynamic changes that occur in tissue with cerebral hypoxia.The results demonstrated that cerebral hypoxia occurs at an early stage in diffuse axonal injury.Cerebral hypoxia was evident 12 hours after injury and declined slightly 24 hours after injury,but was significantly higher than in the control group.The pathological changes that underpin microcirculatory dysfunction did not occur at the same time as axonal injury,but did occur simultaneously with neuronal injury.Cerebral hypoxia plays a key role in promoting the secondary brain injury that occurs after diffuse axonal injury.