缺血缺氧后5周大脑损伤患者的神经纤维束损伤：弥散张量成像证据

Hypoxic-ischemic brain injury (HI-BI) is one of the most common causes of severe neurological disability. Some studies have reported diffusion tensor imaging (DTI) findings of neonatal patients with HI-BI. However, very little is known about DTI in the adult brain. The present study reports on a 15-year-old male patient with HI-BI, who exhibited no specific focal lesions on conventional brain MRI at 5 weeks. However, neural tract injuries were revealed by DTI. Seven control subjects were also evaluated. The patient suffered from cardiac arrest due to ventricular fibrillation for a period of 10-15 minutes. At 4 weeks after onset of cardiac arrest, although he was conscious and alert, he exhibited mild quadriparesis and severe cognitive dysfunction. DTI was acquired at 5 weeks after HI-BI onset. Decreased fractional anisotropy or voxel number of neural tracts suggested partial injury of the corticospinal tract, fornix, and cingulum. Disruptions of the fornix and cingulum on DTI confirmed neural tract injury. DTI could serve as a useful tool for evaluating the state of neural tracts in patients with HI-BI.     

Retrograde Wallerian degeneration of cranial corticospinal tracts in cervical spinal cord injury patients using diffusion tensor imaging

Diffusion tensor imaging (DTI) has the potential to reveal disruption of white matter microstructure in chronically injured spinal cords. We quantified fractional anisotropy (FA) and mean diffusivity (MD) to demonstrate retrograde Wallerian degeneration (WD) of cranial corticospinal tract (CST) in cervical spinal cord injury (SCI). Twenty-two patients with complete cervical SCI in the chronic stage were studied with DTI along with 13 healthy controls. Mean FA and MD values were computed for midbrain, pons, medulla, posterior limb of internal capsule, and corona radiata. Significant reduction in the mean FA and increase in MD was observed in the cranial CST in patients with SCI compared with controls, suggesting retrograde WD. Statistically significant inverse FA and MD changes were noted in corona radiata, indicating some restoration of spared white matter tracts. Temporal changes in the DTI metrics suggest progressing degeneration in different regions of CST. These spatiotemporal changes in DTI metrics suggest continued WD in injured fibers along with simultaneous reorganization of spared white matter fibers, which may contribute to changing neurological status in chronic SCI patients.     

弥散张量成像在高血压性脑出血后皮质脊髓束损伤中的应用研究

目的：应用弥散张量纤维束成像（DTI）观察高血压性脑出血（HICH）皮质脊髓束（CST）的损伤,探讨DTI在HICH预后评估的临床应用价值。方法对16例HICH患者（壳核8例,丘脑7例,混合型1例）患者分别于入院时（7 d内）和发病后3个月进行DTI 检查,以及肌力测定和美国国立卫生研究院卒中量表（NIHSS）评分。用平均部分各向异性（FA）和表观弥散系数（ADC）测量血肿层面周围的双侧CST,测定血肿面（患侧）／对侧面（健侧）的FA值和ADC值比率。结果 HICH患者中发病后3个月肌力较好组（肌力4～-5级）的FA值比率与肌力较差组（肌力0～3级）比较,差异有统计学意义。而ADC比值在入院时及发病后3个月都没有差别。所有FA值比率＞0．8患者的运动功能都有改善和预后好。然而有1例患者虽然FA值比率不是很高,但运动功能的预后也很好,其ADC值明显升高。 CST完整的患者入院时和发病后3个月的肌力和NIHSS评分均比CST中断的患者好,发病后3个月是恢复最快的阶段。结论通过DTI的FA值比率可以了解基底核区HICH患者CST的损伤情况,有助于早期预测神经功能的恢复情况和指导治疗方案的制定。     

人脑皮质脊髓束的年龄相关变化

We don't have Chinese abstract. However, If you need abstract in Chinese. I'll make the abstract in chinese and attach it     

弥散张量成像在继发全面性发作癫痫患者中的应用研究

目的 评价弥散张量成像(DTI)对于常规MRI未发现病灶的部分性继发全面性发作癫痫患者的病灶检出能力.方法 使用Siemens 3.0T磁共振成像系统对30例成年继发全面性发作癫痫患者和30例正常对照者进行扫描,得到弥散加权成像,采用基于体素的分析方法对癫痫患者和正常对照组的数据进行分析.结果 癫痫组右侧梭状回和楔前叶、右侧额内侧回和钩回、左侧扣带回、左侧颞下回、左侧小脑扁桃体和左侧中央前回的脑区FA值较正常对照组降低,差异有统计学意义(P＜0.001);癫痫组右侧海马旁回、右侧颞下回、右侧胼胝体、右侧额内侧回、右侧额下回、扣带回、右侧前扣带回、右侧舌回、右侧梭状回和枕中回,左侧颞中回、左侧钩回和左侧中央前回的脑区ADC值较正常对照组升高,差异具有统计学意义(P＜0.001);左侧直回的脑区ADC值较正常对照组降低,差异具有统计学意义(P＜0.001).结论 DTI检查可发现常规MRI检查为阴性的部分性继发全面性发作癫痫患者存在的广泛脑白质微结构异常.     

Diffusion tensor imaging patterns differ in bulbar and limb onset amyotrophic lateral sclerosis

Background

Amyotrophic lateral sclerosis (ALS) is characterized by pronounced clinical heterogeneity in terms of onset and disease progression. Widespread changes in white matter fibres could be observed by diffusion tensor imaging (DTI), which detects alterations in the degree (diffusivity, ADC) and directedness (fractional anisotropy, FA) of proton movement. The aim of the current study was to determine whether different ALS onset types were reflected in different DTI brain patterns.

Methods

Seventeen patients with a diagnosis of ALS (6 bulbar, 11 limb onset) and seventeen age-matched controls received 1.5T DTI, where FA and ADC were analyzed using statistical parametric mapping.

Results

In ALS patients, an increased diffusivity in the white matter was found below the precentral gyrus and along the corticospinal tract (CST) right into the internal capsule. The FA was decreased in the posterior limb of internal capsule and in the subcortical white matter in the precentral gyrus. In bulbar onset increased diffusivity was found in the CST, whilst in limb onset, frontal subcortical areas displayed an increased diffusivity.

Conclusion

DTI changes can be regarded as prominent features in ALS. Herein we were able to demonstrate discriminating brain DTI patterns due to bulbar or limb onset.     

Diffusion kurtosis imaging in mild traumatic brain injury and postconcussional syndrome

Aims of this study were to investigate white matter (WM) and thalamus microstructure 72 hr and 3 months after mild traumatic brain injury (TBI) with diffusion kurtosis imaging (DKI) and diffusion tensor imaging (DTI), and to relate DKI and DTI findings to postconcussional syndrome (PCS). Twenty-five patients (72 hr = 24; 3 months = 23) and 22 healthy controls were recruited, and DKI and DTI data were analyzed with Tract-Based Spatial Statistics (TBSS) and a region-of-interest (ROI) approach. Patients were categorized into PCS or non-PCS 3 months after injury according to the ICD-10 research criteria for PCS. In TBSS analysis, significant differences between patients and controls were seen in WM, both in the acute stage and 3 months after injury. Fractional anisotropy (FA) reductions were more widespread than kurtosis fractional anisotropy (KFA) reductions in the acute stage, while KFA reductions were more widespread than the FA reductions at 3 months, indicating the complementary roles of DKI and DTI. When comparing patients with PCS (n = 9), without PCS (n = 16), and healthy controls, in the ROI analyses, no differences were found in the acute DKI and DTI metrics. However, near-significant differences were observed for several DKI metrics obtained in WM and thalamus concurrently with symptom assessment (3 months after injury). Our findings indicate a combined utility of DKI and DTI in detecting WM microstructural alterations after mild TBI. Moreover, PCS may be associated with evolving alterations in brain microstructure, and DKI may be a promising tool to detect such changes.     

Diffusion tensor imaging reveals changes in non-fat infiltrated muscles in late onset Pompe disease

MRI is a helpful tool for monitoring disease progression in late-onset Pompe disease (LOPD). Our study aimed to evaluate if muscle diffusion tensor imaging (mDTI) shows alterations in muscles of LOPD patients with <10% fat-fraction. We evaluated 6 thigh and 7 calf muscles (both legs) of 18 LOPD and 29 healthy controls (HC) with muscle diffusion tensor imaging (mDTI), T1w, and mDixonquant sequences in a 3T MRI scanner. The quantitative mDTI-values axial diffusivity (λ₁), mean diffusivity (MD), radial diffusivity (RD), and fractional anisotropy (FA) as well as fat-fraction were analyzed. 6-Minute Walk Test (6-MWT) data were correlated to diffusion metrics. We found that mDTI showed significant differences between LOPD and HC in diffusion parameters (P < .05). Thigh muscles with <10% fat-fraction showed significant differences in MD, RD, and λ_1-3. MD positively correlated with 6-MWT (P = .06). To conclude, mDTI reveals diffusion restrictions in muscles of LOPD with and without fat-infiltration and reflects structural changes prior to fatty degeneration.     

轻中型颅脑损伤后认知功能障碍的DTI研究

目的应用弥散张量成像(diffusion tensor imaging,DTI)技术探讨轻中型颅脑损伤病人不同部位脑白质微结构改变与其认知功能障碍的相关性。方法分析127例轻中型颅脑损伤病人的临床资料,伤后10 d采用蒙特利尔认知评估量表(Mo CA)评定有无认知功能障碍,并常规行头颅MRI检查,采集DTI数据,测量两侧额叶、颞叶内侧、顶叶,胼胝体膝部和压部,中脑部位的感兴趣区各向异性分数(FA值)、表观弥散系数(ADC值),并与Mo CA评估结果进行相关性分析。结果以Mo CA量表为标准评定,无认知功能障碍41例(32.28%,无认知障碍组),存在认知功能障碍86例(67.72%,认知障碍组),主要表现为视空间与执行功能、注意力和计算力、语言、抽象能力、延迟记忆的障碍。与无认知障碍的病人相比,认知障碍的病人两侧额叶、颞叶内侧、胼胝体膝部FA值降低,ADC值增加,差异具有统计学意义(P0.01)。结论轻中型颅脑损伤病人早期存在显著认知功能障碍,以视空间与执行功能、注意力和计算力、语言、抽象能力、延迟记忆障碍为主。颅脑损伤后早期认知功能障碍与病人额叶、颞叶、胼胝体白质受损密切相关。     

Diffusion tensor imaging in schizophrenia.

BACKGROUND: Alignment of white matter axons as inferred from diffusion tensor imaging has indicated changes in schizophrenia in frontal and frontotemporal white matter. METHODS: Diffusion tensor anisotropy and anatomical magnetic resonance images were acquired in 64 patients with schizophrenia and 55 normal volunteers. Anatomical images were acquired with a magnetization prepared rapid gradient echo sequence, and diffusion tensor images used a pulsed gradient spin-echo acquisition. Images were aligned and warped to a standard brain, and anisotropy in normal volunteers and patients was compared using significance probability mapping. RESULTS: Patients showed widespread areas of reduced anisotropy, including the frontal white matter, the corpus callosum, and the frontal longitudinal fasciculus. CONCLUSIONS: These findings, which are consistent with earlier reports of frontal decreases in anisotropy, demonstrate that the effects are most prominent in frontal and callosal areas and are particularly widespread in frontal white matter regions.     

高血压脑出血患者偏瘫相关弥散张量成像研究

目的利用磁共振弥散张量成像(DTI)技术研究脑出血患者偏瘫肢体功能障碍情况。方法运用DTI技术检测32例脑出血患者发病3周左右病变侧皮质脊髓束(CST)受损情况,分析其与患肢Brunnstrom评分及NIHSS评分之间的关系。结果 DTI所显示的CST受损程度与Brunnstrom评分呈负相关(P0.001),与NIHSS评分呈正相关(P0.001)。结论 DTI可直观显示与脑出血患者肢体运动功能障碍密切相关的CST受损情况,有助于病情的客观评估。     

BDA皮质脊髓束神经顺行示踪在大鼠脊髓损伤模型中的应用

目的本研究采用生物素标记葡聚糖(Biotin Dextran Amine,BDA)顺行示踪技术来观察大鼠皮质脊髓束(CST)在中枢神经系统中的走行及脊髓损伤后的表现特征。方法20只雌性成年Sprague-Dawley大鼠,分为脊髓损伤组(n=10)和损伤对照组(n=10)。在相当于T7椎板水平用做好标记的显微剪刀剪断脊髓的后2/3。对照组动物术中仅咬除棘突、椎板,不切断脊髓。术后第15 d,所有动物通过立体定向开颅,将10％BDA溶液注入右侧的感觉运动区皮质内。BDA注射2周后,取出大脑和脊髓组织,采用自由漂浮法行BDA染色显影。实验动物于脊髓损伤术前、术后3d、1周、2周、4周采用Basso、Beatlie、Bresnahan(BBB)评分法测量运动功能,所得数据采用两组均数比较t检验进行统计学处理。结果1.脊髓损伤组动物双后肢瘫痪,BBB运动功能评分明显低于损伤对照组,统计学比较差异十分显著(P<0.01);2.BDA顺行示踪显示大脑皮层BDA注射区内见大脑皮层的锥体细胞及其发出的轴突呈阳性染色,BDA阳性染色的皮质脊髓束神经纤维在中脑、桥脑及延髓的腹侧面行走,但在锥体交叉后皮质脊髓束主要(约99％)在对侧脊髓白质的后索中行走。在致伤组动物中,位于脊髓白质后索中的皮质脊髓束纤维在脊髓损伤处终止;在对照组皮质脊髓束纤维染色可一直延伸至L1水平。结论BDA顺行神经     

Harnessing neural activity to promote repair of the damaged corticospinal system after spinal cord injury

As most spinal cord injuries(SCIs) are incomplete,an important target for promoting neural repair and recovery of lost motor function is to promote the connections of spared descending spinal pathways with spinal motor circuits.Among the pathways,the corticospinal tract(CST) is most associated with skilled voluntary functions in humans and many animals.CST loss,whether at its origin in the motor cortex or in the white matter tracts subcortically and in the spinal cord,leads to movement impairments and paralysis.To restore motor function after injury will require repair of the damaged CST.In this review,I discuss how knowledge of activity-dependent development of the CST—which establishes connectional specificity through axon pruning,axon outgrowth,and synaptic competition among CST terminals—informed a novel activity-based therapy for promoting sprouting of spared CST axons after injur in mature animals.This therapy,which comprises motor cortex electrical stimulation with and without concurrent trans-spinal direct current stimulation,leads to an increase in the gray matter axon length of spared CST axons in the rat spinal cord and,after a pyramidal tract lesion,restoration of skilled locomotor movements.I discuss how this approach is now being applied to a C4 contusion rat model.     

Endogenous recovery of injured spinal cord: longitudinal in vivo magnetic resonance imaging

Pathological changes were followed longitudinally with in vivo magnetic resonance imaging (MRI) and behavioral studies in experimental spinal cord injury (SCI). MRI-observed pathology was correlated with histology. On MRI, the cavitated regions of the injured cord were gradually filled with viable tissue between two and 8 weeks postinjury, and a concomitant improvement was observed in the neurobehavioral scores. By weeks 3-6, on MRI, the gray matter (GM) returned in the segments caudal, but not rostral, to the injury site. The corresponding histological sections revealed motor neurons as well as other nuclei in the gray matter immediately caudal to the epicenter, but not at the site of injury, suggesting neuronal recovery in perilesioned areas. The neuronal and neurological recovery appeared to occur about the same time as neovasculature that was reported on the contrast-enhanced MRI, suggesting a role for angiogenesis in recovery from SCI. The role of angiogenesis in neuronal recovery is further supported by the immunohistochemical observation of greater bromodeoxyuridine uptake by blood vessels near the lesion site compared with uninjured cords.     

1H-MRS in spinal cord injury: acute and chronic metabolite alterations in rat brain and lumbar spinal cord

A variety of tests of sensorimotor function are used to characterize outcome after experimental spinal cord injury (SCI). These tests typically do not provide information about chemical and metabolic processes in the injured CNS. Here, we used (1) H-magnetic resonance spectroscopy (MRS) to monitor long-term and short-term chemical changes in the CNS in vivo following SCI. The investigated areas were cortex, thalamus/striatum and the spinal cord distal to injury. In cortex, glutamate (Glu) decreased 1 day after SCI and slowly returned towards normal levels. The combined glutamine (Gln) and Glu signal was similarly decreased in cortex, but increased in the distal spinal cord, suggesting opposite changes of the Glu/Gln metabolites in cortex and distal spinal cord. In lumbar spinal cord, a marked increase of myo-inositol was found 3 days, 14 days and 4 months after SCI. Changes in metabolite concentrations in the spinal cord were also found for choline and N-acetylaspartate. No significant changes in metabolite concentrations were found in thalamus/striatum. Multivariate data analysis allowed separation between rats with SCI and controls for spectra acquired in cortex and spinal cord, but not in thalamus/striatum. Our findings suggest MRS could become a helpful tool to monitor spatial and temporal alterations of metabolic conditions in vivo in the brain and spinal cord after SCI. We provide evidence for dynamic temporal changes at both ends of the neuraxis, cortex cerebri and distal spinal cord, while deep brain areas appear less affected.     

Transient long segment spinal cord hyperintensity after anterior cervical discectomy

A 69-year-old man was admitted to our hospital with progressive numbness in both feet and gait disturbance. MR imaging revealed a large cervical disc herniation resulting in significant spinal cord compression with hyperintensity of the spinal cord on T2-weighted images at C-5/6. Immediately after undergoing anterior cervical discectomy, the patient developed severe weakness of his left hand and lower extremities. MR imaging obtained 5 days after surgery revealed a long segment hyperintensity between C-3 and T-2 on T2-weighted images. This long segment hyperintensity disappeared after 2 weeks of steroid administration. We suspect that the persistent, localised, patchy C-5/6 cord hyperintensity represents spinal cord degeneration due to ischaemia and trauma resulting from the disc herniation. However, the transient long segment hyperintensity may represent oedema, probably due to minor trauma of an already compromised cord, during the decompression surgery. Clinicians should be aware that even careful surgery can result in a significant change in radiological studies and neurological condition.     

Motor recovery at 6 months after admission is related to structural and functional reorganization of the spine and brain in patients with spinal cord injury

This study aimed to explore structural and functional reorganization of the brain in the early stages of spinal cord injury (SCI) and identify brain areas that contribute to motor recovery. We studied 25 patients with SCI, including 10 with good motor recovery and 15 with poor motor recovery, along with 25 matched healthy controls. The mean period post‐SCI was 9.2 ± 3.5 weeks in good recoverers and 8.8 ± 2.6 weeks in poor recoverers. All participants underwent structural and functional MRI on a 3‐T magnetic resonance system. We evaluated differences in cross‐sectional spinal cord area at the C2/C3 level, brain cortical thickness, white matter microstructure, and functional connectivity during the resting state among the three groups. We also evaluated associations between structural and functional reorganization and the rate of motor recovery. After SCI, compared with good recoverers, poor recoverers had a significantly decreased cross‐sectional spinal cord area, cortical thickness in the right supplementary motor area and premotor cortex, and fractional anisotropy (FA) in the right primary motor cortex and posterior limb of the internal capsule. Meanwhile, poor recoverers showed decreased functional connectivity between the primary motor cortex and higher order motor areas (supplementary motor area and premotor cortex), while good recoverers showed increased functional connectivity among these regions. The structural and functional reorganization of the spine and brain was associated with motor recovery rate in all SCI patients. In conclusion, structural and functional reorganization of the spine and brain directly affected the motor recovery of SCI. Less structural atrophy and enhanced functional connectivity are associated with good motor recovery in patients with SCI. Multimodal imaging has the potential to predict motor recovery in the early stage of SCI. Hum Brain Mapp 37:2195–2209, 2016. © 2016 Wiley Periodicals, Inc.