Functional magnetic resonance imaging and the brain: A brief review

Functional magnetic resonance imaging(fMRI) is em-ployed in many behavior analysis studies, with blood oxygen level dependent-(BOLD-) contrast imaging being the main method used to generate images. The use of BOLD-contrast imaging in f MRI has been refined over the years, for example, the inclusion of a spin echo pulse and increased magnetic strength were shown to produce better recorded images. Taking careful precautions to control variables during measurement, comparisons between different specimen groups can be illustrated by f MRI imaging using both quantitative and qualitative methods. Differences have been observed in comparisons of active and resting, developing and aging, and defective and damaged brains in various studies. However, cognitive studies using f MRI still face a number of challenges in interpretation that can only be overcome by imaging large numbers of samples. Furthermore, f MRI studies of brain cancer, lesions and other brain pathologies of both humans and animals are still to be explored.

Aging effects of regional activation in a spatial task A functional magnetic resonance imaging study

BACKGROUND： An increasing number of studies have shown the effects of aging in basic cognitive processing and higher cognitive functions using functional magnetic resonance imaging （fMRI）. However, little is known about the aging effects in diverse cognitive abilities, such as spatial learning and reasoning. OBJECTIVE： To investigate the effect of aging on spatial cognitive performance and regional brain activation based on fMRI. DESIGN, TIME, AND SETTING： A block design for fMRI observation. This study was performed at the fMRI Laboratory, Brain Science Research Center, Korea Advanced Institute of Science and Technology from March 2006 to May 2009. PARTICIPANTS： Eight right-handed, male, college students in their 20s （mean age 21.5 years） and six right-handed, male, adults in their 40s （mean age 45.7 years）, who graduated from college, participated in the study. All subjects were healthy and had no prior history of psychiatric or neurological disorders. METHODS： A spatial task was presented while brain images were acquired using a 3T fMRI system （ISOL Technology, Korea）. The spatial tasks involved selecting a shape that corresponded to a given figure using four examples, as well as selecting a development figure of a diagram. MAIN OUTCOME MEASURES： The accuracy rate （number of correct answers/total number of items x 100%） of spatial tasks was calculated. Using the subtraction procedure, the activated areas in the brain during spatial tasks were color-coded by T-score. The double subtraction method was used to analyze the effect of aging between the two age groups （20s versus 40s）. RESULTS： The cerebellum, occipital lobe, parietal lobe, and frontal lobe were similarly activated in the two age groups. Increased brain activations, however, were observed in bilateral parietal and superior frontal lobes of the younger group. More activation was observed in bilateral middle frontal and right inferior frontal lobes in the older group. Compared with the older group, the younger men exhibited greater spatial performance （P = 0.012）. CONCLUSION： Reduced cognitive function correlated with decreased activation areas in the parietal lobe and altered activation in the frontal lobe.

Motor inhibition efficiency in healthy aging: the role of γ-aminobutyric acid

The ability to cancel a motor response is critical for optimal functioning in various facets of daily life. Hence, efficient inhibitory motor control is a key function throughout the lifespan. Considering the fact that inhibitory motor function gradually declines with advancing age, it is not surprising that the study of motor inhibition in this age group is gaining considerable interest. In general, we can distinguish between two prominent types of motor inhibition, namely proactive and reactive inhibition. Whereas the anticipation for upcoming stops(proactive inhibition) appears readily preserved at older age, the ability to stop an already planned or initiated action(reactive inhibition) generally declines with advancing age. The differential impact of aging on proactive and reactive inhibition at the behavioral level prompts questions about the neural architecture underlying both types of inhibitory motor control. Here we will not only highlight the underlying structural brain properties of proactive and reactive inhibitory control but we will also discuss recent developments in brain-behavioral approaches, namely the registration of neurochemical compounds using magnetic resonance spectroscopy. This technique allows for the direct detection of the primary inhibitory neurotransmitter in the brain, i.e., γ-aminobutyric acid, across the broader cortical/subcortical territory, thereby opening new perspectives for better understanding the neural mechanisms mediating efficient inhibitory control in the context of healthy aging. Ultimately, these insights may contribute to the development of interventions specifically designed to counteract age-related declines in motor inhibition.

The research of myelinization of normal fetal brain with magnetic resonance imaging

OBJECTIVE: To investigate the growth and development of myelin of sheath fetal brain. METHODS: Forty-four cases of pregnant women were imaged with magnetic resonance (MR) at 0.35 T (tesla). The signal changes of the main structures of fetal brain were analysed. RESULTS: The signal intensity of cerebral (except basal ganglia) and cerebellar matter was hypo-signal on the T1WI (T1 weighted spin-echo image), iso-signal of the PDWI (Proton density weighted image) and hyper-signal on the T2WI (T2 weighted spin-echo image). As to the brain stem and basal ganglia, their signal intensities showed difference in different gestational weeks on T1WI. The intensities were of slight hypo-signal before and iso-signal after the 29th week. However, their signal intensities on PDWI and T2WI were the same as those of the cerebral and cerebellar matter. CONCLUSIONS: There was no myelinization of fetal cerebral (except basal ganglia) and cerebellar matter during pregnant period. The myelin sheath was formed in the brain stem and basal ganglia after 29 gestational weeks. The process of myelinization began from brain stem to basal ganglia.

MRI Evaluation of Lateral Geniculate Body in Normal Aging Brain Using Quantitative Susceptibility Mapping

Objective To investigate the changes of lateral geniculate body （LGB） in the normal aging brain using quantitative susceptibility mapping （QSM） technique. Methods Magnetic resonance （MR） phase and magnitude images were acquired from enhanced gradient echo T2 star weighted angiography sequence with 16 echoes on 3.0T MR system using the head coil with 32 channels. Morphology Enabled Dipole Inversion （MEDI） method was applied for QSM, and the susceptibility value of LGB was measured by region of interest （ROI） drawn manually on three orthogonal planes. Results LGB of the middle-aged group had a higher susceptibility value （0.16±0.05 ppm） than that of the youth group （0.12±0.05 pprn） and elderly group （0.13±0.03 ppm） （all P〈0.05）. Partial correlation analysis demonstrated that there was significantly positive correlation between susceptibility value and age in the youth group （r=0.71, P〈0.05）. Conclusion LGB could clearly be identified on QSM in the brain in vivo.

Two-dimensional horizontal visibility graph analysis of human brain aging on gray matter

Characterizing the trajectory of the healthy aging brain and exploring age-related structural changes in the brain can help deepen our understanding of the mechanism of brain aging.Currently,most structural magnetic resonance imaging literature explores brain aging merely from the perspective of morphological features,which cannot fully utilize the grayscale values containing important intrinsic information about brain structure.In this study,we propose the construction of two-dimensional horizontal visibility graphs based on the pixel intensity values of the gray matter slices directly.Normalized network structure entropy(NNSE)is then introduced to quantify the overall heterogeneities of these graphs.The results demonstrate a decrease in the NNSEs of gray matter with age.Compared with the middle-aged and the elderly,the larger values of the NNSE in the younger group may indicate more homogeneous network structures,smaller differences in importance between nodes and thus a more powerful ability to tolerate intrusion.In addition,the hub nodes of different adult age groups are primarily located in the precuneus,cingulate gyrus,superior temporal gyrus,inferior temporal gyrus,parahippocampal gyrus,insula,precentral gyrus and postcentral gyrus.Our study can provide a new perspective for understanding and exploring the structural mechanism of brain aging.

正常前列腺组织IVIM-DWI的可重现性研究及年龄相关性分析

目的：探讨体素内不相干运动扩散加权成像（IVIM-DWI）各相关参数在正常前列腺组织中的可重现性，并分析其随年龄的变化趋势。材料与方法将66名符合纳入标准的各年龄段健康志愿者分成三组（A组，15～30岁，13名；B组，31～50岁，25名；C组，≥51岁，28名），在3.0 T磁场强度下对志愿者行IVIM-DWI扫描，休息30 min后行第二次IVIM-DWI扫描（b值0、25、50、75、100、150、200、400、600、800、1000、1200、1500、2000、3000 s/mm2），应用双指数模型对信号衰减进行分析得出slow ADC值，fast ADC值及f值。采用配对样本t检验研究前后两次扫描之间的差异，探讨各参数的可重现性；采用方差分析（ANOVA）及LSD法对各参数在不同年龄段正常前列腺组织中的差异进行比较，分析其随年龄的变化趋势。结果 A组健康志愿者前列腺中央腺fast ADC值两次测量数据差异有统计学意义（P=0.022），其余各参数两次测量数据差异没有统计学意义；slow ADC值外周带A、B组及A、C组间差异有统计学意义，B、C组间差异无统计学意义，中央腺A、C组及B、C组间差异有统计学意义，A、B组间差异无统计学意义；fast ADC值外周带及中央腺各组两两间均无显著性差异；f值外周带各组两两间均有显著性差异，中央腺A、C组及B、C组间差异有统计学意义，A、B组间差异无统计学意义；前列腺外周带及中央腺slow ADC值、f值总体上随年龄段升高呈上升趋势。结论不同年龄段正常前列腺组织的IVIM-DWI各相关参数总体上具有良好的可重现性；应用影像学手段，通过对IVIM-DWI相关参数的分析，可以定量的反映前列腺随年龄升高而发生的各种细胞水平的变化，为前列腺疾病的诊断及定量分析提供可靠的依据。

Multisensory mechanisms of gait and balance in Parkinson’s disease:an integrative review

Understanding the neural underpinning of human gait and balance is one of the most pertinent challenges for 21st-century translational neuroscience due to the profound impact that falls and mobility disturbances have on our aging population.Posture and gait control does not happen automatically,as previously believed,but rather requires continuous involvement of central nervous mechanisms.To effectively exert control over the body,the brain must integrate multiple streams of sensory information,including visual,vestibular,and somatosensory signals.The mechanisms which underpin the integration of these multisensory signals are the principal topic of the present work.Existing multisensory integration theories focus on how failure of cognitive processes thought to be involved in multisensory integration leads to falls in older adults.Insufficient emphasis,however,has been placed on specific contributions of individual sensory modalities to multisensory integration processes and cross-modal interactions that occur between the sensory modalities in relation to gait and balance.In the present work,we review the contributions of somatosensory,visual,and vestibular modalities,along with their multisensory intersections to gait and balance in older adults and patients with Parkinson’s disease.We also review evidence of vestibular contributions to multisensory temporal binding windows,previously shown to be highly pertinent to fall risk in older adults.Lastly,we relate multisensory vestibular mechanisms to potential neural substrates,both at the level of neurobiology(concerning positron emission tomography imaging)and at the level of electrophysiology(concerning electroencephalography).We hope that this integrative review,drawing influence across multiple subdisciplines of neuroscience,paves the way for novel research directions and therapeutic neuromodulatory approaches,to improve the lives of older adults and patients with neurodegenerative diseases.

铜转运蛋白C端金属结合域与Ag^+及Hg^(2+)的相互作用

铜转运蛋白(CTR1)不仅参与铜的细胞摄取,而且在其它重金属离子的摄取过程中也发挥重要作用.本文采用紫外-可见(UV-Vis)光谱,核磁共振(NMR)和质谱(MS)的方法,研究了人源CTR1(hCTR1)的C端金属结合域(C8)与Ag+和Hg2+的相互作用.研究表明,Ag+和Hg2+都能与C8结合,但二者与C8的结合机制明显不同.每个C8分子可以结合两个Ag+离子,但一个Hg2+却可以与两个C8形成桥联.此外,Ag+离子与C8的配位是一个中等速度的交换过程,而Hg2+离子则为快速交换过程.C8的半胱氨酸残基是两种离子的重要结合位点,同时组氨酸残基也参与两种金属离子的配位,其中Ag+优先结合组氨酸,而Hg2+则对半胱氨酸的结合具有显著的优势.虽然HCH基序对C8与金属配位至关重要,一些远端的其它氨基酸也可以参与C8与银离子的配位,这可能与CTR1在摄取Ag+过程中的金属转移机制相关.这些结果为理解hCTR1蛋白摄取重金属离子的作用机制提供了必要的信息.

Apparent diffusion coefficient values of normal testis and variations with age

The usefulness of diffusion-weighted magnetic resonance imaging （DWI） in the evaluation of scrotal pathology has recently been reported. A standard reference of normal testicular apparent diffusion coefficient （ADC） values and their variations with age is necessary when interpreting normal testicular anatomy and pathology. We evaluated 147 normal testes using DWI, including 71 testes from 53 men aged 20-39years （group 1）, 67 testes from 42 men aged 40-69 years （group 2） and nine testes from six men older than 70years （group 3）. DWI was performed along the axial plane, using a single shot, multislice spin-echo planar diffusion pulse sequence and b-values of 0 and 900 s mm-2. The mean and standard deviation of the ADC values of normal testicular parenchyma were calculated for each age group separately. Analysis of variance （ANOVA） followed by post hoc analysis （Dunnett T3） was used for statistical purposes. The ADC values （x 10-3 mm2s-1） of normal testicular tissue were different among age groups （group 1：1.08 ± 0.13; group 2：1.15 ±0.15 and group 3：1.31± 0.22）. ANOVA revealed differences in mean ADC among age groups （F= 11.391, P〈 0.001）. Post hoc analysis showed differences between groups 1 and 2 （P= 0.008） and between groups 1 and 3 （P= 0.043）, but not between groups 2 and 3 （P= 0.197）. Our findings suggest that ADC values of normal testicular tissue increase with advancing age.

基于磁共振成像技术的牙龄推断研究进展

牙龄推断是法医学年龄推断的重要内容和实现路径之一,影像技术是牙龄推断的重要技术手段。近年来,有研究初步证实了MRI在评估牙发育方面的可行性,该技术为牙发育评估提供了新的视角和可能性,有望成为更安全且准确的牙龄推断技术手段,但仍需进一步验证其准确性和适应性。本文综述了MRI技术在牙发育和年龄推断中的研究现状、研究瓶颈和局限性,为基于MRI技术的牙龄推断研究提供参考和借鉴。

足月新生儿区域脑体积与生后日龄及神经行为发育的相关性研究

目的分析足月新生儿87个脑区体积与生后日龄及神经行为发育水平之间的相关性。方法回顾性收集2010年11月至2017年9月于西安交通大学第一附属医院行头颅磁共振成像检查(三维T1加权成像)表现正常的足月新生儿75例,胎龄(39.38±1.22)孕周,男/女(51/24);生后日龄(11.11±6.67)d。基于87脑区分割模板,利用VB-Net(V-shape Bottleneck network)深度学习分割技术将新生儿大脑划分为87个脑区并计算各脑区体积,通过Pearson偏相关与线性回归分析各脑区体积与生后日龄以及神经行为学之间的相关性。结果校正胎龄、出生体质量、头围、身长及性别后,足月新生儿全脑66.7%(58/87脑区)脑区体积随生后日龄增加逐渐增大(相关系数r:0.2~0.7,P<0.05)。其中,双侧豆状核、左侧尾状核、右侧枕叶灰质、右侧颞下叶灰质、双侧颞前叶灰质体积与生后日龄呈强相关(r>0.50,P<0.05)。右侧枕叶灰质体积随生后日龄线性增长斜率最大(斜率:100.67),且与行为能力呈正相关(r=0.324,P<0.01)。结论新生儿期全脑多数脑区体积随生后日龄增加而增大,以初级感觉运动相关脑区增长最快,呈空间异质性。部分脑区体积在增长过程中伴随行为能力形成。

不同养护温度下早龄期混凝土导热系数试验研究

为了研究低温环境下的混凝土早龄期的导热系数,采用热流计法导热仪对混凝土试件进行了导热系数测试,考察了-5℃、5℃和20℃养护环境下的早龄期混凝土导热系数,同时测定了各龄期混凝土的抗压强度。采用低场核磁共振技术,研究了不同养护温度下混凝土各龄期的含水率与孔隙率。结果表明:混凝土的含水率与孔隙率随龄期增大逐渐减小,抗压强度随龄期增大逐渐增大,导热系数与龄期和养护温度呈现负相关。

MRI探索儿童斜坡开始黄髓化的年龄界值

目的通过分析儿童正常斜坡的MRI特点,探索儿童斜坡开始黄髓化的年龄界值,以利于更好地识别骨髓病变。材料与方法选取2022年4月至2023年10月在本院放射科行颅脑MRI检查的儿童作为研究对象,通过分析2141例儿童正常斜坡信号特点与年龄分布的关系,探讨儿童斜坡开始黄髓化的年龄界限。在T1WI序列正中矢状面观察斜坡的信号特点,分析未黄髓化及黄髓化年龄分布特点,计算Youden指数及绘制年龄预测斜坡黄髓化的受试者工作特征(receiver-operating chatacteristic,ROC)曲线,探索儿童斜坡开始黄髓化的年龄界值。结果2141例儿童中,男孩1339例,女孩802例。1339例男孩中,未黄髓化者521例(1个月~36个月),黄髓化者818例(4个月~180个月);802例女孩中,未黄髓化者326例(1个月~35个月),黄髓化者476例(5个月~201个月)。男孩年龄为13.5个月时,Youden指数为0.814,ROC曲线下面积(area under the curve,AUC)为0.976,95%置信区间(confidence interval,CI):0.969~0.982;女孩年龄为11.5个月时,Youden指数0.836,AUC为0.980,95%CI:0.973~0.987。结论年龄>13.5个月可作为男孩斜坡开始黄髓化的年龄界值;年龄>11.5个月可作为女孩斜坡开始黄髓化的年龄界值;男孩开始黄髓化的年龄晚于女孩。

孤立性轻中度侧脑室增宽与胎儿脑成熟的相关性

目的利用胎儿脑成熟半定量评分(fTMS)研究孤立性轻中度侧脑室增宽(VM)的胎儿在妊娠中晚期是否存在脑发育异常。资料与方法回顾性分析2018年1月—2022年10月宁夏医科大学总医院接受胎儿MRI的45例正常胎儿和78例异常胎儿,使用fTMS对所有图像进行评分。通过线性回归评估正常和异常胎儿fTMS与孕龄的关系,并分析孤立性轻度和中度VM胎儿与正常胎儿的差异。结果正常胎儿的fTMS与孕龄呈显著正相关(r=0.939,P<0.05),fTMS(Y)与孕龄(X)线性回归方程为:Y=-28.1+1.25X;孤立性轻度和中度VM组的fTMS与孕龄呈显著正相关(r=0.945、0.906,P均<0.05),fTMS(Y)与孕龄(X)线性回归方程为:Y=-28.46+1.24X、Y=-25.57+1.13X;正常胎儿、轻度VM、中度VM的fTMS分别为(10.55±4.25)分、(10.13±4.08)分、(9.22±3.77)分,49例孤立性轻度VM胎儿与正常胎儿的fTMS差异无统计学意义(t=1.651,P>0.05),29例孤立性中度VM胎儿与正常胎儿的fTMS差异有统计学意义(t=2.306,P<0.05)。结论fTMS适用于常规临床使用,并对孤立性中度VM胎儿和正常胎儿脑成熟的差异敏感。

基于MRI扩散张量成像的腰骶丛神经定量研究

目的:探讨影响正常人腰骶丛神经扩散张量成像(DTI)参数值相关临床基线资料,获得腰骶丛神经各向异性分数(FA)、表观扩散系数(ADC)、轴向扩散系数(AD)和径向扩散系数(RD)正常值参考范围。方法:前瞻性搜集60名健康志愿者,年龄平均在20~80岁之间,所有受试者接受3.0T MR扫描,包括DTI和3D-T 2W-FFE序列,由两名医师独立测量腰骶丛L4-S1双侧共360条神经根椎管内、椎间孔内及椎间孔外3个ROI的DTI参数值,计算平均值。采用Pearson相关分析检验DTI参数值与临床基线资料相关性,对与多个临床基线资料相关的DTI参数进行多元线性回归分析。结果:正常人腰骶丛神经FA、ADC、RD、AD值在左右两侧及L4-S1组间差异无统计学意义。平均FA值与年龄(r=-0.687,P<0.001)、体重(r=-0.411,P=0.001)、BMI(r=-0.378,P=0.003)存在负相关性,平均RD值与年龄(r=0.293,P=0.023)存在正相关性。构建关于腰骶丛神经FA值的多元线性回归模型,将与FA值相关变量以逐步法代入,最终年龄和体重作为预测变量,得出FA值的多元线性回归模型,调整后R^(2)=0.620,进一步提出校正公式以根据年龄和体重调整FA值。结论:腰骶丛FA值随着年龄和体重增加而下降,提示涉及腰骶丛DTI研究中考虑年龄和体重因素。

年龄及月经状态对健康女性乳腺动态增强MRI半定量参数的影响

目的观察年龄及月经状态对健康女性乳腺动态增强MRI(DCE-MRI)半定量参数的影响。方法回顾性收集283名因疑诊乳腺包块或乳腺不适而接受MR检查且经临床随访1年无乳腺肿瘤的成年女性;另前瞻性招募49名处于行经期的健康成年女性(行经期亚组)。根据年龄将上述332名受试者分为低龄组(n=107)、中龄组(n=114)及高龄组(n=111),同时根据是否绝经将其分为绝经组(n=112)与未绝经组(n=220,含行经期亚组49名、增殖期亚组77名及分泌期亚组94名)。比较组间、亚组间乳腺DCE-MRI半定量参数(ER_(max),Slope_(max)),包括最大强化率(ER_(max))和最大上升斜率(Slope_(max))的差异及其变异程度。结果高、低龄组间ER_(max)及Slope_(max)差异均有统计学意义(P均<0.05),中龄组ER_(max)和Slope_(max)与低及高龄组差异均无统计学意义(P均>0.05)。绝经组ER_(max)及Slope_(max)均低于未绝经组(P均<0.05)。不同月经周期亚组之间DCE-MRI半定量参数总体差异均无统计学意义(P均>0.05)。低、中及高龄组中,正常乳腺ER_(max)的变异系数(CV)分别为56.20%、44.02%及50.97%,Slope_(max)的CV分别为54.74%、81.78%及76.93%。绝经后及未绝经成年女性正常乳腺ER_(max)的CV分别为50.12%及46.02%,Slope_(max)的CV分别为72.84%及62.04%。各亚组间,ER_(max)及Slope_(max)在增殖期亚组的CV均最大(61.39%、82.54%),而在行月经期亚组的CV均最小(33.99%、42.33%)。结论不同年龄及月经状态下健康女性乳腺DCE-MRI半定量参数存在差异,且个体间变异度较大。

基于MRI的衰老过程中下丘脑及其亚区体积改变与认知功能下降的相关性研究

目的:研究基于MRI自动分割的下丘脑亚区体积和认知功能在成年人生命各个阶段的变化以及两者之间的相关性。方法:选取达拉斯寿命脑科学研究(Dallas Lifespan Brain Study,DLBS)公开数据库提供的314名年龄在20~89岁的健康受试者的结构磁共振成像(structural magnetic resonance imaging,sMRI)图像,并将受试者分为4组:青年组(20~35岁)、中早组(36~50岁)、中老组(51~65岁)和老年组(66~89岁)。使用Freesurfer软件处理sMRI图像得到下丘脑左右侧的前上部、前下部、中上部、中下部以及后部的体积。采用协方差分析比较4组间下丘脑亚区体积的差异,并使用Bonferroni校正进行4组间的多重比较。使用Pearson相关性系数分析下丘脑亚区体积和简易精神状态检查(mini mental state examination,MMSE)、数字比较(digit comparison,DC)测试、数字符号(digit symbol,DS)测试、霍普金斯词语学习测验(Hopkins verbal learning test,HVLT)评分的相关性。结果:除右前下部外,其余下丘脑亚区体积均随着年龄的增长而显著下降(P<0.05)。除右前下部外,其余下丘脑亚区体积均与MMSE评分呈正相关(P<0.05);DC测试评分与所有下丘脑亚区体积呈正相关(P<0.05);DS测试评分与除下丘脑双侧前下部外的下丘脑亚区体积呈正相关(P<0.05);HVLT即时记忆评分与下丘脑双侧前上部、中上部、后部体积呈正相关(P<0.05);HVLT延迟记忆评分与下丘脑双侧前上部、左侧中上部体积呈正相关(P<0.05);HVLT延迟再认评分与下丘脑所有亚区均无相关性(P>0.05);下丘脑的双侧总体积与MMSE、DC测试、DS测试和HVLT即时记忆评分呈正相关(P<0.05)。结论:在成年人的衰老过程中,部分下丘脑亚区体积变化与年龄相关的记忆衰退有关,并且这些区域的体积变化可用于评估整个成年阶段记忆力下降的风险。

磁共振成像质子密度脂肪分数在健康人群大腿骨骼肌评估中的应用

目的探索MRI质子密度脂肪分数(PDFF)和衰减常数T2^(*)值反映骨骼肌衰老的能力。资料与方法前瞻性收集南方医科大学第三附属医院2023年8—12月211名健康成年人大腿中段骨骼肌3.0T MRI数据,记录性别、年龄、身高、体重及计算体重指数(BMI)。于后处理工作站测量大腿骨骼肌的PDFF值和T2^(*)值,比较不同年龄、性别及BMI组的差异,分析大腿骨骼肌PDFF值、T2^(*)值与年龄和BMI的相关性。结果不同年龄组间大腿骨骼肌PDFF值差异均有统计学意义(H=18.476~85.619,P均<0.01),左右股四头肌、腘绳肌和内收肌的T2^(*)值差异有统计学意义(H=13.342~47.566,P均<0.05);男、女组间右股四头肌,左右腘绳肌、内收肌、缝匠肌PDFF值差异均有统计学意义(Z=-4.929~-1.626,P<0.05),左缝匠肌的T2^(*)值差异有统计学意义(Z=-2.971,P=0.003);不同BMI分组各大腿骨骼肌PDFF值均无统计学意义(P均>0.05),左右股四头肌、腘绳肌、内收肌的T2^(*)值差异有统计学意义(H=9.542~24.495,P<0.05)。年龄与各大腿骨骼肌PDFF值呈中度正相关(r=0.635,P<0.01),与左右股四头肌、腘绳肌及缝匠肌T2^(*)值呈轻度负相关(r=-0.451~-0.189,P<0.01)。BMI与各大腿骨骼肌T2^(*)值均呈轻度正相关(r=0.317,P<0.01);各大腿骨骼肌PDFF值与T2^(*)值均呈中度负相关(r=-0.749~-0.624,P<0.01);大腿前后肌群(股四头肌、腘绳肌)PDFF值和T2^(*)值与年龄、BMI的相关性最显著。结论PDFF可反映年龄衰老相关的大腿骨骼肌微环境改变,是精准无创定量评估大腿骨骼肌衰老的潜在影像学生物学标志物。

体检环境中青壮年病毒性脑炎患者CT与MRI诊断性能的比较:一项回顾性分析

目的:评估CT和MRI在体检门诊中对青壮年病毒性脑炎(VE)患者的诊断价值,并比较两种影像学方法的效能。方法:在2020年1月至2023年9月期间,从本院综合诊疗门诊中选取81例确诊为VE的青壮年患者,同时纳入同期体检的81例非VE患者作为对照组。通过ROC曲线和决策树诊断模型对CT和MRI在诊断VE方面的性能进行综合评估。结果:CT和MRI诊断VE的AUC值分别为0.827和0.963,MRI在敏感度(95.06%)、阳性预测值(95.18%)和实际预测准确率(96.30%)方面均显著优于CT(P<0.05)。决策树诊断模型分析结果显示,MRI的误判率为3.70%,预测准确率为96.30%,明显优于CT的相应指标。此外,MRI分级与GCS评分呈现负相关(r=-0.528,P<0.01),表明MRI分级在评估患者预后方面具有较高的价值。结论:MRI在体检门诊青壮年VE的诊断中显示出比CT更高的诊断价值,为临床医护提供了更为可靠的诊断和预后评估工具。