Clinical application of functional magnetic resonance imaging in China

Functional magnetic resonance imaging （fMRI） has been widely used in basic research in the past decade, and more clinically in recent years. Unlike conventional MRI that demonstrates the anatomy and morphology of the brain, fMRI provides the functional information of the brain, including neuronal activation, perfusion, diffusion, metabolism, and fiber connection. Since the publication of the pioneer study by Ogawa et all in 1990, blood oxygenation level dependent （BOLD） technique has been adopted by neuroscientists and psychologists in research into the mechanisms of motion, vision, hearing, language, memory, and functions of the brain. Soon after, clinical studies with BOLD technique were conducted in some fields like surgery （surgical Dlanning）.     

Dynamic contrast-enhanced magnetic resonance perfusion weighted imaging in astrocytomas： correlation with histopathology and immunohistochemistry

Objective： To investigate magnetic resonance perfusion weighted imaging and its relationship with the grading and the expression of vascular endothelial growth factor （VEGF） and angiogenesis in astrocytomas. Methods： A collection of 34 patients with astrocytomas proved by surgery and pathology were examined by magnetic resonance imaging（MRI）, with 26 cases of grade Ⅰ-Ⅱ （low-grade） and 8 cases of grade Ⅲ-Ⅳ （high-grade）. MR perfusion images were obtained with spin-echo echo planar imaging （SE-EPI） techniques. Expression of VEGF was examined by immunohistochemical method of streptavidin-biotin-peroxidase（SP）. The vascular development was measured by micro-vascular density （MVD） which was immunostained with anti-factor Ⅷ-related antigen monoclonal antibody. Results： Both of the expression of VEGF and the angiogenesis in 34 cases of astrocytomas were significantly correlated to the maximum relative cerebral blood volume （Max rCBV） （r=0.604, P〈0.001; r=0.625, P〈0.001, respectively）. The Max rCBV and the expression of VEGF, MVD in high-grade astrocytomas were significantly higher than that of in low-grade astrocytomas （t=3.0, P=0.017; t=7.08, P=0.01; t=3.37, P=0.011, respectively）. Conclusion： MR perfusion weighted imaging might be a valuable method in in vivo study of the angiogenesis of astrocytomas and evaluating their malignant degree and prognosis.     

Gender and magnetic resonance imaging classification-related differences in clinical and biochemical characteristics of Cushing＇s disease： a single-centre study

Background Cushing＇s disease （CD） presents a remarkable preponderance in female gender,and a significant minority of patients with CD presented with negative magnetic resonance imaging （MRI） findings.The aim of this study was to evaluate gender-related and MRI classification-related differences in clinical and biochemical characteristics of CD.Methods We retrospectively studied 169 patients with CD,comprising 132 females and 37 males,and 33 patients had no visible adenoma on MRI.Results We observed that male and MRI-positive patients presented with high adrenocorticotropic hormone （ACTH） values （P ＜0.05）.Female patients presented with higher prevalence of hirsutism and hyperpigmentation and lower prevalence of purple striae （P ＜0.05）.The prevalence of buffalo-hump and hypertension was greater in MRI-negative patients （P ＜0.05）.In addition,male patients with CD presented at a younger age compared with females （P ＜0.05）.Patients with fatigue and hypokalaemia presented significantly higher urinary-free cortisol,ACTH and cortisol levels compared with patients without these symptoms （P ＜0.05）.The prevalence of LH reduction,hyper total cholesterol （TC） and hyper low-density lipoprotein was more frequent in MRI-positive patients （P ＜0.05）.Hyper-TC levels and PRL reduction were more frequent in males （P ＜0.05）.T3,T4 and FT3 levels negatively correlated with age at diagnosis （r=-0.310,P ＜0.01; r=-0.191,P ＜0.05; r＝-0.216,P ＜0.05）.T3,T4,FT3 and FT4 levels significantly negatively correlated with 8-am plasma cortisol levels （r=-0.328,P ＜0.01; r=-0.195,P ＜0.05; r=-0.333,P ＜0.01; r＝-0.180,P ＜0.05）.Females presented higher total protein level （P ＜0.01） and lower blood urea nitrogen and serum creatinine levels （P ＜0.01）,compared with male patients.Conclusions Carefulness and caution are required in all patients with CD,because of the complexity of clinical and biochemical characteristics in CD patients of different gender and MRI cl     

Volumetric magnetic resonance imaging classification for Alzheimer’s disease based on kernel density estimation of local features

Background The classification of Alzheimer's disease (AD) from magnetic resonance imaging (MRI) has been challenged by lack of effective and reliable biomarkers due to inter-subject variability.This ar...     

Magnetic resonance imaging of Alzheimer’s disease: from diagnosis to therapeutic evaluation

Alzheimer＇s disease（AD）is a devastating late-life dementia that produces progressive loss of memory and mental faculties in elderly people.It is important to identify the earliest evidence of AD and to monitor the development of this disease for us to make positive response to its management.Magnetic resonance imaging（MRI）is powerful to image the tissue or organ without damnification.MRI can be employed to diagnose the early AD development and monitor the key biomarker development in AD.MRI may be helpful not only in diagnosing early AD,but also in evaluating its development.This article reviews the progress of MRI on the diagnosis and detection of AD,and makes comments on its therapeutic application.     

SPIO-enhanced magnetic resonance imaging for differentiating metastatic from hyperplastic lymph nodes： A study in rabbits

To investigate the potential of superparamagnetic iron oxide particles (SPIO) in MR imaging for the differentiation between hyperplastic and metastatic lymph node. Methods: Animal models of malignant lymph node metastasis were established in 6 New-Zealand rabbits by a unilateral intra-muscular injection of VX2 carcinoma cells,and models of hyperplastic lymph nodes were induced in another 6 rabbits by a unilateral intra-muscular injection of egg yolk emulsion. MR images of the lymph nodes were obtained before and 12 h after interstitial injection of SPIO. Image results were analyzed and compared with pathological findings. Results: On unenhanced images, the signal intensity of hyperplastic and metastatic lymph nodes did not differ significantly. After administration of SPIO, the signal intensity of beth hyperplastic and metastatic lymph nodes remained unchanged on T1-weighted SE images. On T2-weighted SE ima-ges, the signal intensity of hyperplastic lymph nodes decreased heterogeneously, while that of all metastatic ones re-mained unchanged. On T2-weighted GRE images, the signal intensity of hyperplastic lymph nodes decreased signifi-cantly and homogeneously, while that of 4 metastatic ones remained unchanged and that of the rest 2 decreased hetero-geneously. Conclusion: SPIO-enhanced MR imaging may enable the differentiation between the hyperplastic and meta-static lymph nodes.     

Initial experience with circumferential pulmonary vein ablation guided by fusion of magnetic resonance imaging with three-dimensional electroanatomic mapping

Catheter ablation for the treatment of atrial fibrillation （AF） has been a focal target ofelectrophysiological study in recent years. Up to date, circumferential pulmonary vein ablation （CPVA） guided by three-dimensional （3-D） electreanatomic mapping （Carto, USA） has been one of the most favourable procedures for the treatment of AF. However, it is still difficult to acquire the detailed information on number, location, and branching pattern of all pulmonary veins （PVs） when the 3-D electroanatomic mapping system is used alone.     

Magnetic resonance imaging on complications of breast augmentation with injected hydrophilic polyacrylamide gel

The injection augmentation mammaplasty for cosmetic purpose has been popular recently in China. Two kinds of injectable material are used clinically, autologous fat and biomaterial. The fat injection for breast augmentation is in question with the major problems of progressive fat re-absorption, microcalcification, and fat liquefaction. Now, the principal alloplastic biomaterial for injection augmentation mammaplasty in China is hydrophilic polyacrylamide gel （HPAAG）. Although thousands of breasts have been augmented with HPAAG and it seems to be a good biocompatible material, some complications develop after HPAAG injection augmentation mammaplasty.The patients had to undergo surgery to remove the injected HPAAG and associated lesions. Ultrasonography or magnetic resonance imaging （MRI） should be taken preoperatively to demonstrate the distribution of injected HPAAG and associated lesions. In this report, the diagnostic value and clinical significance of MRI on the complications of HPAAG breast augmentation were discussed.     

Three-dimensional-fast imaging employing steady-state acquisition and T2-weighted fast spin-echo magnetic resonance sequences on visualization of cranial nerves Ⅲ-Ⅻ

Because of the small diameter and complex anatomic course of the cranial nerves except for the optic nerve, trigeminal nerve, facial nerve, and cochlear and vestibular nerve, other cranial nerves are difficult to be visualized in magnetic resonance imaging （MRI） scanning with conventional thickness （5-10 mm）. With the rapid development of MRI technology high spatial resolution, three-dimensional and two-dimensional magnetic resonance imaging technologies have been used in recent years in the observation of normal and abnormal cranial nerves, including three-dimensional constructive interference in steady state （3D CISS） sequence, three- dimensional magnetization-prepared rapid gradient-echo （3D MP-RAGE） sequence, three-dimensional fast inflow with steady-state precession （3D FISP） seohuence, and some fast spin-echo （FSE） sequences. - Threedimensional fast imaging employing steady-state acquisition （3D-FIESTA） is a fast three-dimensional steady-state imaging sequence with high spatial resolution and contrast between the organizational structures. And this sequence was reportedly used in the study on the diseases in the cerebellopontine angle; inner ear and posterior fossa tumors.7＇8 However, the reports about the value of 3D-FIESTA sequence for the visualization of normal cranial nerves are still rare.     

Diagnosis of systemic arterial diseases with whole-body 3D contrast-enhanced magnetic resonance angiography

Background With the development of magnetic resonance （MR） technologies, whole-body 3D contrastenhanced MR angiography （3D CE MRA） has become possible. The purpose of this study was to introduce and evaluate this technique in demonstration of various systemic arterial diseases. Methods Thirty-seven patients underwent whole-body 3D CE MRA using a 1.5T MR imager. The patients included were with clinically documented or suspected peripheral arterial occlusive disease （PAOD, n=19）, Takayasu arteritis （n=8）, polyarteritis nodosa （n=1）, Type B dissection （n=4） and thoracic and/or abdominal aneurysm （n=5）. Sixty-eight surface coil elements were employed to encompass the whole body. Four 3D CE MRA stations were acquired successively through automatic table moving. A total scan range of 188 cm, covering the arterial tree from carotid artery to trifurcation vessels, was acquired. Overall image quality of each arterial segment and venous overlay were assessed and rated. The depiction of various systemic arterial diseases was evaluated and compared with other imaging modalities if available, including digital subtraction angiography （DSA）, CT angiography, dedicated mono-station MRA. Results Whole-body 3D CE MRA was well tolerated by all patients. It yielded a detailed display of the arterial system with a short examination time. The image quality was considered diagnostic in 99.3% of the arterial segments. The remaining 0.7% of the arterial segments were considered non-diagnostic. In 7 of 19 patients with PAOD, whole-body MRA showed additional vascular narrowing apart from peripheral arterial disease. In 9 patients with vasculitis, whole-body MRA depicted luminal irregularity, narrowing or occlusion, aneurysm and collateral circulation involving multiple vascular segments. Whole-body MRA also clearly revealed the severity and extent of dissection and aortic aneurysm. In 20 cases the vascular pathologies demonstrated on whole body MRA were confirmed by other imaging investigations. Conclusions The whole-body MRA technique was non-invasive, quick and easy to perform. It was valuable for a comprehensive evaluation of vascular involvement of various systemic arterial diseases.     

fMRI在脑肿瘤诊断中的应用价值初探

目的：探讨fMRI在脑肿瘤诊断、鉴别诊断及肿瘤浸润边界划定中的价值。方法：脑肿瘤35例,均行MR平扫、增强、DWI及MRS。在肿瘤强化区、瘤周区、正常参照区,DWI测量各区域信号值,计算相对表观扩散系数（rADC）值;^1H—MRS行MVS采集NAA、Cho、Cr、Lac等波峰,计算不同区域各代谢物比值均值,比较统计学差异。结果：DWI示肿瘤强化区rADC值在脑膜瘤与星形细胞瘤、转移瘤间有显著性差异（P〈0．05）;瘤周区rADC值在星形细胞瘤与脑膜瘤、转移瘤间有统计学差异（P〈0．05）。多体素^1H—MRS示肿瘤强化区各代谢物比值均值与正常参照区比较有显著性差异（P〈0．05）;瘤周区,星形细胞瘤、转移瘤和脑膜瘤间多组代谢物比值具统计学差异（P〈0．05）。结论：fMRI与常规MRI相结合有助于脑肿瘤的鉴别诊断以及确定病灶浸润范围。     

Functional magnetic resonance imaging and immunohisto-

Background The hypothalamus plays a central role in the regulation of metabolism by sensing metabolic demands and releasing regulatory neurotransmitters. This study investigated the response of the hypothalamus to glucose ingestion in rats by blood oxygen level-dependent functional magnetic resonance imaging (BOLD-fMRI) and immunohistochemical techniques to determine the role of the hypothalamus in glycoregulation during disturbances in carbohydrate metabolism. Methods The signal intensity of the hypothalamus was monitored by fMRI for 60 minutes after oral glucose intake in 48 healthy rats (age 14 months), which included 24 normal weight rats (weighing (365±76.5) g) and 24 overweight rats (weighing (714±83.5) g). Then, 12 rats (6 normal, 6 overweight) underwent a repeat fMRI scan after consuming an equivalent amount of water without glucose on a separate day. The procedure for fMRI with water intake was the same as for glucose ingestion. fMRI data was processed using time cluster analysis and intensity averaging method. After fMRI, the expression of neuropeptide Y (NPY) and 5-hydroxytryptamine (5-HT) in the hypothalamus of all rats was determined by immunohistochemistry. Positive cells for NPY or 5-HT were counted. Results There was a transient, but significant, decrease in fMRI signal intensity in all rats (mean (3.12±0.78)%) in the hypothalamus within 19.5–25.5 minutes of oral glucose ingestion. In overweight rats, the decrease in signal intensity in response to the glucose ingestion was more markedly attenuated than that observed in normal weight rats ((2.2±1.5)% vs (4.2±0.7)% inhibition, t=2.12, P<0.05). There was no significant response in the hypothalamus after oral water ingestion. The percentage of NPY positive cells in obese rats were slightly lower than those in control group (21% vs 23%, t=0.71, P>0.05); but there was no significant difference between the two groups; the percentage of 5-HT positive cells in obese rats were significantly lower than those in the control group (22% vs 31%, t=3.25, P<0.01).Conclusions There is a transient, but significant, decrease in BOLD signal intensity in the hypothalamus following glucose ingestion, which is similar to that observed in humans. The response of the hypothalamus to glucose ingestion was different in overweight and normal weight rats. The percentage of NPY positive cells in obese rats were lower than those in the control group, although this difference was not statistically significant. The percentage of 5-HT positive cells in obese rats was significantly lower than those in the control group.     

基于静息态 fMRI 的难治性癫痫患者丘脑功能连接研究

目的：利用静息态功能磁共振成像（fMRI）中的功能连接方法,探讨难治性癫痫患者丘脑的功能连接改变及意义。方法难治性癫痫患者19例,多模态神经影像学检查中颅内均未发现明显致痫病灶,发作间期及发作期长程视频脑电图提示双侧大脑半球棘波及棘慢波;同期招募19例健康对照者。采集静息态 fMRI 数据,分别以左、右丘脑为感兴趣区（ROI）与全脑进行功能连接分析,了解难治性癫痫患者相对于正常对照组功能连接增高和减弱的区域。结果以左侧丘脑为 ROI 做功能连接分析,难治性癫痫组与双侧梭状回、右侧舌叶、双侧楔叶及双侧楔前叶的功能连接强度增强,而与双侧尾状核、左侧壳核及左侧杏仁核的功能连接强度减弱;以右侧丘脑为 ROI 做功能连接分析,难治性癫痫组与双侧距状回、双侧楔前叶及左侧直回的功能连接强度增强,而与双侧壳核、双侧尾状核、双侧杏仁核及右侧脑岛的功能连接强度减弱。结论难治性癫痫患者静息状态下丘脑功能连接异常,丘脑可能参与了“癫痫网络”的构成。     

网络成瘾大学生脑功能性磁共振成像特点

目的:利用任务背景刺激功能性磁共振成像（functional magnetic resonance imaging,fMRI）,探讨网络成瘾(internet addiction,IA)大学生的脑功能特点.方法:以网络游戏内容作为实验刺激任务,采用组块设计方法,对19名IA大学生及19名正常对照受试者进行脑部fMRI....     

原发性失眠症功能磁共振成像研究进展

原发性失眠症（PI）是一种常见的睡眠障碍,会影响人的认知、情绪调节等功能。多项研究表明PI涉及广泛的脑区异常。近年来,功能磁共振成像技术结合不同的分析方法被广泛应用于PI的研究,它可以客观、间接地分析大脑功能活动的改变,有助于阐明PI的神经病理学机制,并为疾病的早期诊断提供可靠的客观依据。本文综述了近年来任务态功能磁共振成像、静息态功能磁共振成像等技术和功能连接分析方法在PI中的应用。     

局灶性癫痫发作期的功能磁共振成像的研究

目的:采用脑电联合功能磁共振成像方法,观察发作期癫痫引起的脑活动情况,探讨皮层及皮层下结构在癫痫发作及传播中的作用及其神经机制.方法:1例行脑电同步功能磁共振成像检查的局灶性癫痫患者,回顾性发现其在采集期间多次轻微癫痫发作,在保证功能磁共振数据质量的情况下,分析两段采集过程中癫痫发作活动引起脑活动的改变情况.结果:两次数据采集得到一致的脑激活结果:双侧顶叶、内颞叶大脑皮层广泛激活信号,双侧纹状体、丘脑及脑干诸皮层下灰质核团明显激活信号,以左侧为著;小脑蚓部、中央叶、右小脑半球及齿状核亦有明显激活信号;全脑最大激活点位于左顶叶.结论:在局灶性癫痫发作时,大脑皮层原发灶与皮层下诸结构形成往返神经环路;大脑皮层和脑干网状结构是癫痫对侧传播的主要部位;皮层下结构在癫痫发作类型及传播中起重要的调节作用.     

数字工作记忆的脑功能磁共振定位研究

目的通过功能磁共振成像（functional magnetic resonance imaging,fMRI）技术研究健康人脑处理数字工作记忆的神经基础。方法选取12名有利手健康志愿者进行一项数字工作记忆任务,同时进行fMRI扫描。实验采用组块设计,记忆任务和对照任务交替进行,采用SPM99软件进行数据分析和脑功能区定位。结果当统计阈值概率设为P〈0．01时,任务所激活的脑区有额叶[布鲁德曼分区（Brodmannarea,BA）6／9／46]、顶叶（BA7／40）、双侧海马、双侧扣带回、丘脑、尾状核以及小脑,其中额叶的激活最为显著（P〈0．05）,额叶和顶叶的激活都表现为左侧半球优势（P〈0．05）。结论左侧额叶在人脑数字工作记忆中起重要作用,其他皮层脑区及皮层下结构也共同参与完成数字工作记忆的信息处理过程。     

前牙早接触状态紧咬的功能性磁共振成像

目的研究前牙早接触状态紧咬时中枢调控区域定位的具体变化,为咬合病的病理生理机制研究提供理论支持。方法在正常志愿者口内前牙上预置人工咬合高点,利用GE 3.0T磁共振扫描机获取其在正常咬合状态和前牙早接触状态紧咬时的脑功能成像图,借助SPM2软件进行分析比较。结果正常咬合状态紧咬时的中枢激活区包括中央前回M1区、中央后回S1区、前运动区、前额叶皮层、岛叶、Broca’s区、缘上回、小脑、扣带回、右侧顶叶皮层及右侧枕叶皮层。前牙早接触状态紧咬时的中枢激活区包括中央前回M1区、左侧中央后回S1区、左侧前运动区及右侧Broca’s区。结论初步明确正常咬合状态及前牙早接触状态紧咬时的中枢激活区域,发现早接触对中枢相应调控区域有抑制激活的作用。     

持续性姿势感知性眩晕的功能磁共振成像研究进展

持续性姿势感知性眩晕（PPPD）是临床上最常见的头晕类型之一,具有与焦虑、抑郁等情绪障碍密切相关和视觉依赖2个临床特点,但发病机制尚不明确,缺乏客观检查手段,极易误诊。近年来神经影像学技术的发展为进一步探究PPPD的病理生理机制提供了重要手段。本文通过分析近年PPPD患者静息态、任务态及结构功能磁共振成像的研究进展,发现PPPD的2个临床特点可能与相关脑区结构或功能变化有关,这为PPPD的诊疗提供了新的思路。     

基于功能磁共振成像的肝豆状核变性患者纹状体亚区损害及临床分析

目的基于功能磁共振成像分析肝豆状核变性（Wilson disease, WD）患者纹状体亚区神经功能损害及其与临床相关分析,探讨其神经心理学症状可能的致病机制。方法收集WD患者29例和健康志愿者30例,进行3.0 T磁共振功能磁共振成像及临床量表测试,采用mICA工具箱的group ICA功能将壳核和尾状核分成8个亚区,做全脑功能连接,提取功能连接异常区域的值与临床量表测试结果做相关性分析。结果与对照组相比,WD患者左侧尾状核中部与全脑未发现功能增强或减弱区域,余感兴趣区与全脑功能连接不同程度减弱。左侧尾状核前部（ROI5）-中扣带回功能连接值与简易智能状态量表（MMSE）值呈显著负相关（r=-0.47,P=0.009）;右侧尾状核前部（ROI6）-中扣带回功能连接值与MMSE值呈显著负相关（r=-0.46,P=0.011）;右侧尾状核中部（ROI8）-右侧岛叶功能连接值与MMSE值呈显著负相关（r=-0.38,P=0.041）。结论右侧尾状核前中部与背外侧前额叶功能连接减弱,双侧壳核前部与丘脑功能连接减弱,可能破坏皮质-纹状体-丘脑回路引起认知功能损害;参与记忆及动作相关认知的突显网络、默认模式网络的通路连接受阻则可能是WD患者认知障碍的神经病理机制。