功能磁共振成像/弥散张量成像图像融合:脑肿瘤治疗术前计划新方法

Objective To develop and test an image fusion software(fDf,fMRI/DTI fusion) which can overlap the anatomical(T1WI images), functional MRI(fMRI) and diffusion tensor imaging( DTI) sim-ultaneously for preoperational evaluation of patients' tumor. Methods fMRI with bilateral hands grasp move-ment and DTI were performed using GE 1. 5 T magnetic resonance system on 10 subjects (5 healthy volun-teers and S patients with brain tumor,of which 3 were metastases, 1 was cavernous hemangioma and 1 was gli-oma). All data were input to the personal computer and off-line postprocessing of fMRI and DTI data was per-formed using SPM5 and Volume-One software package to visualize the activated functional cortex areas and corticospinal tracts. fDf was used to import the fMRI and structural images to Volume-One to show them sim-ultaneously. Results Brain functional activation maps and diffusion tensor fiber tracking images were ob-tained in all five healthy volunteers and four patients except one who suffered from left hemiplegia. The func-tional activation maps and the fiber tracking images were successfully fused by the fDf software,where the ac-tivations areas and the white matter fiber were displayed together. The fusion images of healthy volunteers showed the hand motion areas and corresponding corticospinal tracts, while that of the patients display the re-lationship of the eloquent cortex and peritumoral fiber tracts, which were useful in guiding the treatments for the surgeons and radiotherapists. It only took hours to present the fused images to the neurosurgeons or the ra-diotherapists. Conclusions All the results confirm that the image fusion software work well for all the data.It is an easy,free and fast way to realize the image fusion. The neurosurgeon and radiotherapist consider the software were very helpful for preoperative planning.

3-N-butylphthalide is an effective drug for acute ischemic stroke. However, its effects on chronic cerebral ischemia-induced neuronal injury remain poorly understood. Therefore, this study li-gated bilateral carotid arteries in 15-month-old rats to simulate chronic cerebral ischemia in aged humans. Aged rats were then intragastrically administered 3-n-butylphthalide. 3-N-butylphtha-lide administration improved the neuronal morphology in the cerebral cortex and hippocampus of rats with chronic cerebral ischemia, increased choline acetyltransferase activity, and decreased malondialdehyde and amyloid beta levels, and greatly improved cognitive function. These findings suggest that 3-n-butylphthalide alleviates oxidative stress caused by chronic cerebral ischemia, improves cholinergic function, and inhibits amyloid beta accumulation, thereby im-proving cerebral neuronal injury and cognitive deifcits.

Depression is closely linked to the morphology and functional abnormalities of multiple brain regions;however, its topological structure throughout the whole brain remains unclear. We col-lected resting-state functional MRI data from 36 ifrst-onset unmedicated depression patients and 27 healthy controls. The resting-state functional connectivity was constructed using the Auto-mated Anatomical Labeling template with a partial correlation method. The metrics calculation and statistical analysis were performed using complex network theory. The results showed that both depressive patients and healthy controls presented typical small-world attributes. Compared with healthy controls, characteristic path length was signiifcantly shorter in depressive patients, suggesting development toward randomization. Patients with depression showed apparently abnormal node attributes at key areas in cortical-striatal-pallidal-thalamic circuits. In addition, right hippocampus and right thalamus were closely linked with the severity of depression. We se-lected 270 local attributes as the classiifcation features and their P values were regarded as criteria for statistically significant differences. An artificial neural network algorithm was applied for classiifcation research. The results showed that brain network metrics could be used as an effec-tive feature in machine learning research, which brings about a reasonable application prospect for brain network metrics. The present study also highlighted a signiifcant positive correlation between the importance of the attributes and the intergroup differences;that is, the more sig-niifcant the differences in node attributes, the stronger their contribution to the classiifcation. Experimental ifndings indicate that statistical signiifcance is an effective quantitative indicator of the selection of brain network metrics and can assist the clinical diagnosis of depression.

The Kinect-based virtual reality system for the Xbox 360 enables users to control and interact with the game console without the need to touch a game control er, and provides rehabilitation training for stroke patients with lower limb dysfunctions. However, the underlying mechanism remains un-clear. In this study, 18 healthy subjects and five patients after subacute stroke were included. The five patients were scanned using functional MRI prior to training, 3 weeks after training and at a 12-week fol ow-up, and then compared with healthy subjects. The Fugl-Meyer Assessment and Wolf Motor Function Test scores of the hemiplegic upper limbs of stroke patients were significantly increased 3 weeks after training and at the 12-week fol ow-up. Functional MRI results showed that contralateral primary sensorimotor cortex was activated after Kinect-based virtual reality training in the stroke patients compared with the healthy subjects. Contralateral primary sensorimotor cortex, the bilateral supplementary motor area and the ipsilateral cerebel um were also activated during hand-clenching in al 18 healthy subjects. Our findings indicate that Kinect-based virtual reality training could promote the recovery of upper limb motor function in subacute stroke patients, and brain reorganization by Kinect-based virtual reality training may be linked to the contralateral sen-sorimotor cortex.

Episodic memories are composed of various interrelated elements, including those specific to items of central interest and those pertaining to related features, such as the color, shape, size, spatial location, temporal order, and media or modalities of presentation. Memory about a core item (such as a word, object, or picture) is cal ed item memory while memory about the context or related fea-tures of a core item is defined as source memory. What determines which sources within an episode are successful y remembered is of particular interest to researchers. Behavioral evidence suggests that the orientation of a memory task influences whether the related source of the item wil be re-membered later. This study explored changes in the hippocampus and prefrontal cortex while par-ticipants completed two tasks:an item-oriented task and a source-oriented task. We used functional MRI to investigate the neural mechanisms by which task orientation influences source encoding. We found that subsequent source memory effects in the right prefrontal cortex and hippocampus were modulated by task orientation, whereas task orientation modulated item memory effects in the prefrontal cortex. These findings highlight the possibility that the hippocampus contributes to the intentional encoding of item-source associations, whereas the prefrontal cortex is biased toward processing information to which attention is directed.

Embodied semantics theory asserts that the meaning of action-related words is neural y represented through networks that overlap with or are identical to networks involved in sory-motor processing. While some studies supporting this theory have focused on Chinese cha-racters, less attention has been paid to their semantic radicals. Indeed, there is stil disagreement about whether these radicals are processed independently. The present study investigated whether radicals are processed separately and, if so, whether this processing occurs in sensory-motor gions. Materials consisted of 72 high-frequency Chinese characters, with 18 in each of four ries:hand-action verbs with and without hand-radicals, and verbs not related to hand actions, with and without hand-radicals. Twenty-eight participants underwent functional MRI scans while reading the characters. Compared to characters without hand-radicals, reading characters with hand-radicals activated the right medial frontal gyrus. Verbs involving hand-action activated the left inferior parietal lobule, possibly reflecting integration of information in the radical with the semantic meaning of the verb. The findings may be consistent with embodied semantics theory and suggest that neural representation of radicals is indispensable in processing Chinese characters.

Brain structure and cognitive function change in the temporal lobe, hippocampus, and prefrontal cortex of patients with mild cognitive impairment and Alzheimer’s disease, and brain network-connection strength, network efficiency, and nodal attributes are abnormal. However, existing research has only analyzed the differences between these patients and normal controls. In this study, we constructed brain networks using resting-state functional MRI data that was extracted from four populations mal controls, patients with early mild cognitive impairment, patients with late mild cognitive impairment, and patients with Alzheimer’s disease) using the Alzheimer’s Disease Neuroimaging Initiative data set. The aim was to analyze the characteristics of resting-state functional neural networks, and to observe mild cognitive impairment at different stages before the transformation to Alzheimer’s disease. Results showed that as cognitive deficits increased across the four groups, the shortest path in the rest-ing-state functional network gradual y increased, while clustering coefficients gradual y decreased. This evidence indicates that dementia is associated with a decline of brain network efficiency. In tion, the changes in functional networks revealed the progressive deterioration of network function across brain regions from healthy elderly adults to those with mild cognitive impairment and Alzhei-mer’s disease. The alterations of node attributes in brain regions may reflect the cognitive functions in brain regions, and we speculate that early impairments in memory, hearing, and language function can eventual y lead to diffuse brain injury and other cognitive impairments.

Shaoyang acupoints are the most frequently used in migraine treatment. However, the central anal-gesic mechanism remains poorly understood. Studies have demonstrated that single stimulus of the verum acupuncture in healthy subjects can induce significant connectivity or activity changes in pain-related central networks compared with sham acupuncture. However, these findings are not indicative of the central analgesic mechanism of acupuncture at Shaoyang acupoints. Thus, we recruited 100 migraine sufferers and randomly assigned them into five groups: Shaoyang uncommon acupoint, Shaoyang common acupoint, Yangming uncommon acupoint, non-acupoint control, and blank control groups. Subjects were subjected to evaluation of curative effects and functional MRI prior to and after 10 and 20 acupuncture treatments. Al subjects were diagnosed by physicians and enrol ed fol owing clinical physical examination. Subjects were observed during 1-4 weeks after inclusion. At the fifth week, the first clinical evaluation and resting functional MRI were conducted. The Shaoyang uncom-mon acupoint, Shaoyang common acupoint, Yangming uncommon acupoint, and non-acupoint control grousp then were treated with acupuncture, five times per week, 20 times in total over 4 weeks. The second and third clinical evaluations and resting functional MRI screenings were conducted fol owing 10 and 20 acupuncture treatments. The blank control group was observed during the 5 to 8 week pe-riod, fol owed by clinical evaluation and resting functional MRI. The aim of this study was to examine changes in brain functional activity and central networks in subjects with migraine undergoing acu-puncture at Shaoyang uncommon acupoints. This study provides a further explanation of the central analgesic mechanism by which acupuncture at Shaoyang acupoints treats migraine.

积极开展脑功能MRI的临床应用研究

近年来医学影像学取得飞速发展,其中MRI技术的进步更令人瞩目,继1946年美国哈佛大学的Purcell和斯坦福大学的Bloch发现MR并因此获得诺贝尔物理学奖之后,美国Stony Brook纽约州大学的Paul Lauterbur和英国诺丁汉大学的Peter Mansfield由于发明MRI技术共同获得了2003年度生理学和医学诺贝尔奖,不排除在不远的将来血氧水平依赖(blood oxygen level dependent,BOLD)脑功能MRI(functional MRI,fMRI)的发明者[1-2]获得诺贝尔奖的可能.

磁共振功能成像在前列腺癌诊断中的应用

前列腺癌是男性泌尿系统常见的恶性肿瘤,是欧美国家男性发病率第一和死亡率第二的肿瘤[1].我国前列腺癌的发病率较欧美低,但目前有明显的上升趋势.近年来磁共振成像( magnetic resonance imaging,MRI)越来越多地应用于前列腺癌的诊断.本文就MRI在前列腺癌诊断中的研究进展做如下综述.

人类脊髓功能磁共振成像的研究进展

随着医学影像技术的不断发展,影像诊断模式也发生很大转变,从单纯的形态解剖诊断转向与功能代谢相结合.从1990年美国贝尔实验室学者OGAWA等[1]首次提出血氧水平依赖(blood oxygenation level dependent,BOLD)效应,并迅速应用于大脑功能成像的研究,到1996年YOSHIZAWA等[2]首次证明了脊髓功能磁共振成像(spinal functional MRI,s-fMRI)的可行性和有效性后,神经系统影像学从此进入一个崭新的时代,对神经系统疾病的研究做出重大贡献.脊髓功能磁共振成像能够在完全无创条件下观察脊髓的解剖和功能状态,正逐步应用到脊髓相关的基础和临床研究中,对探索脊髓生理病理、评价脊髓功能、指导临床治疗及疗效检测等具有广阔的应用前景.现就近年来国内外有关人类脊髓功能磁共振成像的研究综述如下.

抑郁症患者静息态功能磁共振成像研究进展

抑郁症是一种高患病率和高致残率的精神疾病,患者往往伴有注意、执行控制、情绪等认知障碍,而基于症状学对抑郁症的发病机制、临床诊断和疗效评价的研究一直未得到突破性进展,限制了对疾病本质的认识和治疗模式的探讨.磁共振技术的产生促进了对脑神经机制的深入探讨,使得抑郁症的研究可以扩展到脑功能、神经物质代谢改变等层面.基于影像学对抑郁症的研究有阳性发现[1-2],本文主要通过总结静息态功能磁共振成像(restingstate functional MRI, rsfMRI)研究成果,综述不同类型疾病导致的抑郁症患者静息状态下脑功能变化情况.

静息态功能磁共振成像在多发性硬化的应用

多发性硬化(multiple sclerosis,MS)是一种神经系统炎性脱髓鞘疾病,其症状涉及多方面的功能障碍.传统的MRI对显示MS的受损病灶很敏感,但对于认知功能障碍的反映比较局限,不能提供MS患者认知功能损害的直接信息.近年来脑功能磁共振成像(functional magnetic resonance imaging,fMRI)方法受到广泛关注,尤其是静息态功能磁共振成像(resting state functional MRI,rfMRI)方兴未艾,促进对大脑机理的认识和理解.对于MS组织结构损害与组织修复之间复杂的平衡关系,部分rfMRI研究提示患者受损的神经皮质可重塑,大脑功能损害可代偿.本文就静息态磁共振功能成像在多发性硬化的研究进展进行回顾与综述.

轻度创伤性脑损伤的功能磁共振研究进展

近年来,轻度创伤性脑损伤(mild traumatic brain injury,mTBI)的发病率逐渐趋升,约占全部颅脑外伤的75%,已成为一个严重的社会公共卫生问题[1]。mTBI 患者通常在伤后出现短暂的意识丧失(<30 min)和/或记忆缺失(<24 h),部分患者伤后数月或数年存在持久的脑震荡综合征(post concussion syndrome,PCS)[2-3],主要表现为躯体(如头痛、疲倦)、认知(如记忆、注意、计划)以及精神(如焦虑、冲突、抑郁等)上的功能障碍[4]。由于 mTBI 患者脑损伤程度相对较轻,PCS 症状缺乏一定的特异性,并且常规神经影像学检查多无异常,易造成临床重视程度不够,使患者得不到及早的诊断及治疗。另外,在司法诉讼案例中,对 mTBI 后出现的 PCS 症状,特别是仅有的一些以躯体性不适为主诉的案例,其鉴定结论具有很大争议[5]。因此,找到一个客观性指标对 mTBI 患者大脑受损程度做出较早的诊断和评定,进一步判定mTBI 的伤情、预后,为临床及时治疗和司法鉴定提供可靠的依据,具有重要的社会意义和经济价值。同时,通过对 mTBI 患者伤后恢复期的脑功能研究,有助于了解 PCS 的发生及功能恢复中潜在的神经机制,对神经精神疾病领域的研究具有重大的科学指导意义。