外周神经损伤后大脑皮层功能重组fMRI研究

脑的可塑性和功能重组是近年来热点课题,功能磁共振技术的发展为其系统研究提供了可靠的保证.就脑功能重组现象及研究脑功能的各种功能性神经影像学技术的原理、特点和功能磁共振成像的临床、实验研究进展予以综述.     

屈光参差性弱视皮层功能损害fMRI视网膜脑图研究

目的 利用血氧水平依赖性功能磁共振成像(BOLD fMRI)视网膜脑图技术(retinotopic mapping),研究屈光参差性弱视皮层功能损害的发生机制. 资料与方法 以1.5T MRI系统采集8例单眼屈光参差性弱视患者枕叶视觉皮层对于视网膜脑图刺激和6 cpd空间频率黑白光点刺激的功能数据,比较弱视眼和健眼在初、高级视觉皮层功能区功能反应;对初、高级皮层间功能损害进行回归分析. 结果 弱视眼在V1、V2、V3、VP、V7区反应T值低于健眼( P＜0.05 ),在V3a、V4、V8区弱视眼与健眼T值无统计学差异;V1区与V2、V3、VP、V7区之间反应减低相关分析无统计学意义( P＞0.05 ). 结论 弱视患者初、高级视觉皮层均存在功能损害,两者之间无明显因果关系;在高级视觉皮层,背、腹侧传导通路均有功能损害;fMRI视网膜脑图技术为深入研究弱视初、高级视觉皮层功能损害的发病机制提供了新的方法.     

运动皮层的功能磁共振成像研究

目的　用MR血氧水平依赖性成像技术 (BOLD)研究正常人及癫痫、脑肿瘤患者对指运动皮层的功能磁共振成像 (fMRI)。方法　 3 4例受试者 ,其中 8例正常志愿者 ,2 0例癫痫患者 ,6例脑肿瘤患者 ,行右手、左手对指运动共 43次 ,采用BOLD技术进行相应脑功能区成像。结果　所有受试者均能在MR脑功能检查中表现出局部脑功能活动区规律的信号时间变化曲线 ,并得以清晰成像。功能区附近的占位病变可造成局部功能区的移位和缩小等改变 ,原发性癫痫患者未见有对指运动功能区的明显改变。结论　BOLD -fMRI在活体人脑对指运动的功能区定位方面是一个有效的方法。对需实施手术的颅内占位病变进行BOLD -fMRI检查对指导手术有价值。需改进癫痫患者的脑功能研究 ,进行更有效的相关功能刺激     

脑梗死患者手运动功能区fMRI研究

目的 对不同时期脑梗死所致偏瘫患者采用主动手运动任务模式进行功能磁共振成像(functional magnetic resonance imaging,fMRI),研究运动功能区损伤及恢复特点,以指导临床康复治疗.资料与方法 脑梗死所致偏瘫患者40例.累及基底节区25例,皮层区15例.其中急性期15例,亚急性期9例,慢性期16例.采用组块设计进行单手拇指与余4指同步对指运动,所有患者均进行健侧和患侧手的主动运动实验.采用SPM 99软件进行预处理和统计分析.结果 (1)急性期梗死灶累及皮层区组,健侧半球初级感觉运动区(SMC)激活强度及范围明显大于患侧半球.皮层区组患侧半球SMC激活强度及范围均小于基底节区组;(2)梗死灶累及基底节区组,健侧与患侧半球SMC激活强度及范围于急性期与慢性期间差异无统计学意义;(3)病例的纵向观察:患肢功能恢复较好的患者,患侧和(或)健侧半球SMC的激活强度和(或)范围有不同程度增强,同时激活脑区增多,均可见小脑半球的激活;患肢功能恢复较差的患者,患侧半球SMC的激活强度及范围逐渐减小直至消失.结论 (1)fMRI能准确地判定脑梗死患者脑功能区的损伤程度及有无重组的脑功能区;(2)皮层区梗死患者运动功能受损较为严重,SMC起关键作用,其受累程度直接影响运动功能损伤的等级及恢复程度;(3)脑梗死偏瘫患者在运动功能康复治疗过程中,病变周围及远隔部位可出现功能和结构变化,提示存在脑功能区重组.     

健侧C7神经移位术后大脑运动皮层功能重组的功能MRI研究

目的利用功能MRI（fMRI），观察健侧C7神经移位术后大脑运动皮层的变化特征。方法随访经临床和手术证实的因全臂丛神经损伤而接受健侧C7神经移位术者13例，左侧损伤者10例，右侧者3例。根据手部运动功能的恢复情况，将病例分为2组：a组10例，息手不能自主运动。b组3例，患手可以自主运动。另外，选择12名健康志愿者作为对照。所有受检者均接受了fMRI，扫描方法采用平面回波血氧水平依赖（BOLD）序列，利用SPM99软件对图像进行处理分析。结果患者健侧和患侧上肢运动诱发激活区最强信号体素主要出现于对侧半球初级运动皮层（PMC），健侧肢体运动诱发同侧PMC激活者10例，患侧肢体运动诱发同侧PMC激活者7例；a组受检者健侧上肢运动诱发对侧PMC激活区形态正常者9例，手部运动诱发平均激活区大小为3159个体素，肩部运动诱发平均激活区大小为1746个体素。患侧手部和肩部运动诱发对侧PMC激活区扩大者各有6例；b组受检者患肢运动诱发双侧PMC出现激活者1例，对侧PMC激活者2例。结论外周神经损伤可以引起大脑运动皮层的改变；患肢躯体代表区可以在神经损伤以后相当长时期内存在并对运动的心理表达产生应答；健侧C7神经移位术后中枢神经系统重组可能发生在多种水平上，并且可以受到多种因素影响。     

顶叶不同部位在计算任务中作用的fMRI研究

目的用功能MRI探讨顶叶的不同部位在计算时的活动情况。方法对18例正常青年受试者进行简单及复杂任务的功能MRI扫描,采用SPM2软件进行数据分析和脑功能区定位。结果简单及复杂计算时主要可见额前区、顶叶、小脑及枕叶的激活,顶叶的激活以顶下区为主;随着计算难度的增大,可见顶上区的激活增加。结论顶下区是计算任务的主要部位,随着计算难度的增大,顶上区的作用明显增加。     

fMRI在视皮层功能及弱视神经机制研究中的应用

近年来功能磁共振成像技术在脑功能活动研究中得到了迅速的发展，已广泛应用于神经科学的各个领域。其中在视觉系统研究中已取得了重要成果，并于近几年应用于弱视神经机制的研究中。就该技术在视觉皮层功能及弱视神经机制研究中的应用进行综述。     

外周神经损伤后大脑皮层功能重组fMRI研究

脑的可塑性和功能重组是近年来热点课题，功能磁共振技术的发展为其系统研究提供了可靠的保证。就脑功能重组现象及研究脑功能的各种功能性神经影像学技术的原理、特点和功能磁共振成像的临床、实验研究进展予以综述。     

昏迷患者静息态脑功能局部一致性fMRI研究

目的 探讨昏迷患者生物学特征可能的基线脑功能基础.方法 昏迷患者及正常人各12例,使用飞利浦3.0T磁共振系统对受试者进行全脑静息状态功能磁共振成像(fMRI)检查.用SPM5及北京师范大学认知神经科学与学习国家重点实验室自行研制开发的REST及DPARSF软件进行数据的处理和统计学分析,比较昏迷患者与正常人在静息状态下局部一致性的差异.结果 与正常人相比,昏迷患者组小脑、颞叶、额叶、顶下小叶、后扣带回及楔前叶的自发活动局部一致性减低 (P<0.01).结论 运用静息态脑功能成像可能为研究昏迷患者的病理生理状态提供新的方向;昏迷患者在静息状态下多个脑区ReHo值显著低于健康对照,提示昏迷神经生理机制并非单一脑区功能的异常改变,而是整个大脑功能网络的异常,是一种大脑功能失连接的表现.     

青光眼患者视觉皮层激活的fMRI评价

目的 应用功能磁共振成像(fMRI)评价青光眼患者视觉皮层的激活情况,分析视野改变与视觉皮层激活间的对应关系.资料与方法 30例青光眼患者和30名健康自愿者进行左、右眼单眼刺激组块设计的fMRI实验.刺激为全屏幕黑白翻转棋盘格,对照为中心带静止白色圆点的黑色屏幕.在1.5 T MR扫描仪行血氧水平依赖(BOLD)-fMRI,6个对照组块与5个刺激组块交替进行,每个组块20 s.采用SPM2软件进行数据处理.观察青光眼患者左、右眼单独刺激时视觉皮层的激活情况并与对照组比较.结果 青光眼和正常对照组左、右眼刺激各16例入组.(1)青光眼左、右眼刺激时双枕叶视觉皮层均激活,且均以右枕叶视觉皮层激活为主;(2)与正常对照组比较,青光眼左、右眼刺激时双枕叶视觉皮层激活强度和范围减低,且均以右枕叶视觉皮层激活减低为主;(3)9例中晚期青光眼患者,视野缺损主要表现为管状视野和视野颞侧视岛.左、右眼刺激时视觉皮层激活方式不同,左眼刺激以右枕叶视觉皮层激活为主,右眼刺激则以左枕叶视觉皮层激活为主.结论 fMRI可以反映青光眼患者视野缺损和视觉皮层激活的对应关系,进而推断视网膜病变的部位和程度,有助于指导临床诊断和治疗.     

气功态时脑运动皮质低频活动同步性的静息fMRI研究

目的:通过观察气功师在气功态与非气功态,以及与非练功者之间脑运动皮质低频活动同步性的差异,探讨气功的本质及其对脑功能皮质的影响.材料和方法:研究对象为练功20年以上,以静功为主的气功师5名,以及相匹配年龄、性别并从未练过气功的对照5名.研究采用GE Signa VH/i 3.0T磁共振扫描机,先后进行无任务(静息态)和运动任务的BOLD序列扫描.通过计算运动皮质体素时间信号序列两两之间的交互相关系数以及平均交互相关系数(MCC),评价脑运动皮质低频信号的同步性.练功与非练功者,气功态与非气功态运动皮质的MCC值的差异用t检验进行评价.结果:所有被试者运动任务的fMRI检查均获得双侧运动皮质的明显激活.非练功者运动皮质的MCC值平均为0.20,练功者非气功态时MCC值平均为0.26,气功态时平均为0.40.经t检验非气功态时,练功者与非练功者脑运动皮质低频信号间的MCC值的差别无明显统计学意义,而练功者气功态与非气功态之间,练功者气功态与非练功者之间MCC值的差别有明显统计学意义,P＜0.01.结论:进入气功状态后,脑运动功能皮质低频活动的同步性会明显增强.但这种反映同步的相关系数是否可以作为其特征性的指标尚有待于进一步研究.     

Abnormal brain function in neuromyelitis optica: A fMRI investigation of mPASAT

PurposeCognitive impairment with the Neuromyelitis Optica (NMO) patients is debated. The present study is to study patterns of brain activation in NMO patients during a pair of task-related fMRI.Materials and methodsWe studied 20 patients with NMO and 20 control subjects matched for age, gender, education and handedness. All patients with NMO met the 2006 Wingerchuk diagnostic criteria. The fMRI paradigm included an auditory attention monitoring task and a modified version of the Paced Auditory Serial Addition Task (mPASAT). Both tasks were temporally and spatially balanced, with the exception of task difficulty.ResultsIn mPASAT, Activation regions in control subjects included bilateral superior temporal gyri (BA22), left inferior frontal gyrus (BA45), bilateral inferior parietal lobule (BA7), left cingulate gyrus (BA32), left insula (BA13), and cerebellum. Activation regions in NMO patients included bilateral superior temporal gyri (BA22), left inferior frontal gyrus (BA9), right cingulate gyrus (BA32), right inferior parietal gyrus (BA40), left insula (BA13) and cerebellum. Some dispersed cognition related regions are greater in the patients.ConclusionsThe present study showed altered cerebral activation during mPASAT in patients with NMO relative to healthy controls. These results are speculated to provide further evidence for brain plasticity in patients with NMO.     

ALS患者运动皮层区的静息态功能磁共振成像分数低频振幅研究

目的 应用静息态功能磁共振成像(rs-fMRI)分数低频振幅(fALFF)方法对肌萎缩侧索硬化(ALS)患者运动皮层区基线脑活动变化进行研究. 方法 使用Siemens Trio Tim 3.0 T MRI对ALS组和正常对照组(各12例)分别进行静息态fMRI扫描.静息态fMRI数据处理助手(DPARSF)基于Matlab 2009a平台进行数据预处理并计算fALFF值,使用WFU PickAtlas软件提取运动皮层区[布鲁德曼(BA)4区和BA6区],应用静息态fMRI数据处理助手(REST)两样本t检验比较两组运动皮层区fALFF的改变.并分析运动皮质区存在显著差异脑区的fALFF值与临床参数如肌萎缩侧索硬化功能等级量表(ALSFRS-r)、病程、疾病预后比值的相关性.结果 相对正常对照组,ALS患者皮质运动区fALFF值降低区域主要位于双侧中央前回、双侧辅助运动区(P＜ 0.05,AlphaSim校正);相对于正常对照组,ALS患者皮质运动区fALFF值升高区域主要位于左侧中央前回、左侧辅助运动区、左侧旁中央小叶(P＜ 0.05,AlphaSim校正).其中左侧中央前回和患者的ALSFRS-r呈正相关(r=0.605,P=0.037);左侧旁中央小叶和患者的ALSFRS-r呈负相关(r=-0.633,P=0.027).差异脑区fALFF值和疾病病程、疾病预后比值之间并无显著的相关性(P值范围分别是0.154 ～0.968,0.303 ～0.995).结论 ALS患者存在运动皮质区神经元活动的异常,左侧中央前回fALFF值减低、左侧旁中央小叶fALFF值增高或可作为ALS患者疾病严重程度的潜在定量标志之一.表明fALFF是定量观测ALS运动皮质功能改变的一个有用指标.     

A New Method of Selective, Rapid Cooling of the Brain: An Experimental Study

Purpose To determine whether retrograde perfusion of cooled blood into one internal jugular vein (IJV) in the pig can selectively reduce the brain temperature without affecting the core body temperature (CBT). Methods In 7 domestic pigs, the left IJV was catheterized on one side and a catheter placed with the tip immediately below the rete mirabile. Thermistors were placed in both brain hemispheres and the brain temperature continuously registered. Thermistors placed in the rectum registered the CBT. From a catheter in the right femoral vein blood was aspirated with the aid of a roller pump, passed through a cooling device, and infused into the catheter in the left IJV at an initial rate of 200 ml/min. Results Immediately after the start of the infusion of cooled blood (13.8°C) into the IJV, the right brain temperature started to drop from its initial 37.9°C and reached 32°C within 5 min. By increasing the temperature of the perfusate a further drop in the brain temperature was avoided and the brain temperature could be kept around 32°C during the experiment. In 4 of the animals a heating blanket was sufficient to compensate for the slight drop in CBT during the cooling period. Conclusions We conclude that brain temperature can be reduced in the pig by retrograde perfusion of the internal jugular vein with cooled blood and that the core body temperature can be maintained with the aid of a heating blanket.     

Disrupted functional connectivity of the hippocampus in patients with hyperthyroidism: Evidence from resting-state fMRI

Objective

The hippocampus expresses high levels of thyroid hormone receptors, suggesting that hippocampal functions, including cognition and regulation of mood, can be disrupted by thyroid pathology. Indeed, structural and functional alterations within the hippocampus have been observed in hyperthyroid patients. In addition to internal circuitry, hippocampal processing is dependent on extensive connections with other limbic and neocortical structures, but the effects of hyperthyroidism on functional connectivity (FC) with these areas have not been studied. The purpose of this study was to investigate possible abnormalities in the FC between the hippocampus and other neural structures in hyperthyroid patients using resting-state fMRI.

Methods

Seed-based correlation analysis was performed on resting-state fMRI data to reveal possible differences in hippocampal FC between hyperthyroid patients and healthy controls. Correlation analysis was used to investigate the relationships between the strength of FC in regions showing significant group differences and clinical variables.

Results

Compared to controls, hyperthyroid patients showed weaker FC between the bilateral hippocampus and both the bilateral anterior cingulate cortex (ACC) and bilateral posterior cingulate cortex (PCC), as well as between the right hippocampus and right medial orbitofrontal cortex (mOFC). Disease duration was negatively correlated with FC strength between the bilateral hippocampus and bilateral ACC and PCC. Levels of depression and anxiety were negatively correlated with FC strength between the bilateral hippocampus and bilateral ACC.

Conclusion

Decreased functional connectivity between the hippocampus and bilateral ACC, PCC, and right mOFC may contribute to the emotional and cognitive dysfunction associated with hyperthyroidism.     

正常人工作记忆任务和静息状态下前额叶皮层内侧面的功能连接分析

目的 分析在工作记忆任务和静息两种状态下与前额叶皮层内侧面(MPFC)正、负相关脑区的分布,比较两种状态下MPFC功能连接的差异.资料与方法 采用GE 1.5 T MR扫描仪对25名正常自愿者行静息态及2-back工作记忆任务的功能磁共振成像(fMRI)实验,2-back实验采用组块设计,0-back作为对照,6个对照组块与5个任务组块交替进行.静息态全脑采集128个时相.采用SPM、AFNI对数据进行预处理.选择MPFC作为种子点与全脑其他像素进行Pearson相关分析,建立相关图.组内分析时采用随机效应模型单样本t检验,检测与MPFC明显正相关或负相关的脑区.组间分析采用配对样本t检验.检测MPFC功能连接图在2-back任务和静息状态下的差异.结果 两种状态下与MPFC正相关的脑区基本一致,属于"任务负激活网络".2-back任务状态下与MPFC负相关的脑区与"任务正激活网络"一致.静息状态下与MPFC负相关的脑区主要分布在双侧岛叶、双侧顶下小叶,且这些区域的负相关性明显高于任务状态.任务状态下负相关性高于静息状态的主要脑区包括双侧运动前区外侧(LPMA)、双侧顶叶后部(PPC)、左侧丘脑及右侧小脑半球.结论 静息及2-back任务状态下MPFC的功能连接情况不同,对于正常人在静息及任务状态下的功能连接对比研究为临床精神疾病患者的研究奠定了基础.     

虚拟现实结合减重平板训练对脑卒中患者步行功能恢复的作用和机制:纵向功能磁共振研究

目的:探讨虚拟现实结合减重平板训练(VR+BWSTT)在急性脑卒中患者步行功能早期恢复中的作用和机制.方法:将11例急性缺血性脑卒中患者随机分入跑台组(6例)和常规组(5例),分别采用不同的康复训练方案,并在康复训练前及训练后3周、3个月和6个月各行一次脑功能成像和下肢运动功能评定.结果:跑台组步行速度和下肢Fugl-Meyer评分进步程度较常规组显著,跑台组进步较大的患者患肢对侧旁中央小叶(PCL)激活强度较训练前增大较明显;患肢运动激活辅助运动区(SMA)的LI值训练后3周多数为负值;跑台组6名患者中有4名训练后3周患肢运动时出现双侧前额叶皮层多发激活区.结论:VR+BWSTT对脑卒中患者步行功能的改善作用优于常规步态训练;下肢功能恢复的中枢神经机制与上肢不完全相同;VR的作用机制可能与双侧前额叶皮质有关.     

Timing-Invariant CT Angiography Derived from CT Perfusion Imaging in Acute Stroke: A Diagnostic Performance Study

BACKGROUND AND PURPOSE:Timing-invariant (or delay-insensitive) CT angiography derived from CT perfusion data may obviate a separate cranial CTA in acute stroke, thus enhancing patient safety by reducing total examination time, radiation dose, and volume of contrast material. We assessed the diagnostic accuracy of timing-invariant CTA for detecting intracranial artery occlusion in acute ischemic stroke, to examine whether standard CTA can be omitted.MATERIALS AND METHODS:Patients with suspected ischemic stroke were prospectively enrolled and underwent CTA and CTP imaging at admission. Timing-invariant CTA was derived from the CTP data. Five neuroradiologic observers assessed all images for the presence and location of intracranial artery occlusion in a blinded and randomized manner. Sensitivity and specificity of timing-invariant CTA and standard CTA were calculated by using an independent expert panel as the reference standard. Interrater agreement was determined by using κ statistics.RESULTS:We included 108 patients with 47 vessel occlusions. Overall, standard CTA and timing-invariant CTA provided similar high diagnostic accuracy for occlusion detection with a sensitivity of 96% (95% CI, 90%–100%) and a specificity of 100% (99%–100%) for standard CTA and a sensitivity of 98% (95% CI, 94%–100%) and a specificity of 100% (95% CI, 100%–100%) for timing-invariant CTA. For proximal large-vessel occlusions, defined as occlusions of the ICA, basilar artery, and M1, the sensitivity and specificity were 100% (95% CI, 100%–100%) for both techniques. Interrater agreement was good for both techniques (mean κ value, 0.75 and 0.76).CONCLUSIONS:Timing-invariant CTA derived from CTP data provides diagnostic accuracy similar to that of standard CTA for the detection of artery occlusions in acute stroke.

Stroke imaging research currently focuses on prediction of patient outcome and identifying patients who are suitable for neurointerventional treatment.^1,2 For these purposes, advanced stroke imaging protocols typically add CT perfusion imaging or diffusion-weighted MR imaging to the traditional work-up, consisting of noncontrast CT and CT angiography.^2,3 Noncontrast CT is used to differentiate hemorrhagic stroke from ischemic stroke and to assess early signs of ischemia. CTA is used to localize arterial occlusions and to identify proximal large-vessel occlusions that may be suitable for endovascular treatment. CT perfusion imaging and DWI are used to assess the extent and severity of hypoperfusion and particularly increase the sensitivity of imaging in the early stages of ischemic stroke.⁴ The practical advantages of CT perfusion imaging are that it is widely available and does not delay treatment decisions because it is fast and most patients already undergo CT scanning.³Currently, CTA can be derived from CT perfusion data. Such an approach allows the enhancement of patient safety by reducing the total scanning time, radiation dose, and amount of contrast material needed.⁵ In CT perfusion imaging, multiple scans after intravenous injection of contrast material are obtained with time, generating a 4D dataset, which is used to derive cerebral perfusion maps such as the cerebral blood flow, cerebral blood volume, and arrival times. When imaging is performed on a CT scanner with large spatial coverage, however, this 4D data can also be used to provide CT angiographic information, referred to as 4D-CTA or dynamic CTA. Previous studies have assessed whether 4D-CTA can be used for detection of vascular occlusion in a stroke setting but found that image quality was moderate and diagnostic performance for stroke assessment was limited because large-vessel occlusions may be missed.^5–8 Recently, a different approach to obtain CTA from CT perfusion source data was presented that combines the whole 4D-CTA dataset into 1 high-quality 3D-CTA dataset by displaying maximum contrast enhancement with time.⁵ This technique is referred to as “timing-invariant CTA” because it is insensitive to delayed contrast arrival and was shown to provide similar-to-superior image quality compared with standard CTA.⁵The aim of our study was to test the diagnostic performance of timing-invariant CTA for stroke evaluation, to assess whether standard CTA can be omitted when CT perfusion imaging has been performed.     

脊髓型颈椎病患者解压术后大脑皮层结构重塑的MRI研究

目的 应用基于体素形态学测量(VBM),研究脊髓型颈椎病(CSM)患者解压术前、后大脑感觉运动网络(SMN)内的脑区灰质体积的改变,探讨CSM患者大脑感觉运动皮层结构损伤机制及其参与术后结构重塑的神经机制.方法 采用3.0T磁共振对21例CSM患者与21名匹配健康对照者进行容积MRI扫描,并进行随访复查;基于VBM方法,采用独立或配对样本t检验比较CSM患者解压术前、术后大脑感觉运动皮层灰质体积改变情况,及Pearson线性分析异常脑区灰质体积改变情况和临床功能评估之间的相关性.结果 与健康对照者比较,CSM患者术前左侧小脑前叶、左侧顶下小叶、右侧额中回、右侧中央前/后回灰质及双侧岛叶灰质体积减小;CSM患者术后3个月复查,左侧小脑后叶、右侧颞中回及颞上回、右侧丘脑、双侧辅助运动区灰质体积较术前减小,左侧顶下小叶、右侧顶上小叶、右侧中央前回/中央后回灰质体积增加;较健康对照者双侧岛叶灰质体积减小及双侧小脑前叶灰质体积增加(GRF校正).术前及术后3个月复查时CSM患者组异常区域灰质体积与日本骨科协会评估治疗(JOA)评分、颈椎功能障碍指数(NDI)评分及病程并无明显相关性(P＞0.05).结论 CSM患者解压术前、术后存在感觉运动皮层灰质体积异常,提示脊髓病变可导致大脑结构损伤;解压术后局部灰质趋于正常提示皮质重塑参与CSM术后恢复;CSM患者术前术后感觉运动皮层存在结构性损伤与重塑.     

Characterization of Brain Microstructural Abnormalities in High Myopia Patients: A Preliminary Diffusion Kurtosis Imaging Study

ObjectiveTo evaluate microstructural damage in high myopia (HM) patients using 3T diffusion kurtosis imaging (DKI).Materials and MethodsThis prospective study included 30 HM patients and 33 age- and sex-matched healthy controls (HCs) with DKI. Kurtosis parameters including kurtosis fractional anisotropy (FA), mean kurtosis (MK), axial kurtosis (AK), and radial kurtosis (RK) as well as diffusion metrics including FA, mean diffusivity, axial diffusivity (AD), and radial diffusivity derived from DKI were obtained. Group differences in these metrics were compared using tract-based spatial statistics. Partial correlation analysis was used to evaluate correlations between microstructural changes and disease duration.ResultsCompared to HCs, HM patients showed significantly reduced AK, RK, MK, and FA and significantly increased AD, predominately in the bilateral corticospinal tract, right inferior longitudinal fasciculus, superior longitudinal fasciculus, inferior fronto-occipital fasciculus, and left thalamus (all p < 0.05, threshold-free cluster enhancement corrected). In addition, DKI-derived kurtosis parameters (AK, RK, and MK) had negative correlations (r = −0.448 to −0.376, all p < 0.05) and diffusion parameter (AD) had positive correlations (r = 0.372 to 0.409, all p < 0.05) with disease duration.ConclusionHM patients showed microstructural alterations in the brain regions responsible for motor conduction and vision-related functions. DKI is useful for detecting white matter abnormalities in HM patients, which might be helpful for exploring and monitoring the pathogenesis of the disease.