急性型胼胝体变性的临床表现和影像学特点

目的：探讨急性型胼胝体变性（M BD ）的临床表现和影像学特点。方法对该院诊治的3例急性型M BD患者进行回顾性分析,包括临床表现、实验室检查、影像学检查（头颅CT、MRI）和随访结果。结果3例患者均急性起病,主要表现为意识障碍、精神异常、癫痫发作、谵妄性震颤、高热等;CT与MRI可见胼胝体膝部和压部病灶,CT示病灶为低密度,MRI表现为 T1WI等或低信号,T2WI高信号,液体衰减反转恢复序列高信号,弥散加权成像（DWI）高信号,ADC等或低信号;3例均伴发双侧大脑半球白质对称性病灶,1例出现脑桥臂对称性病灶,1例胼胝体膝部及体部出现类似“三明治”样改变。结论急性型M BD临床表现多样,无特异性,但具有特征性影像学表现。     

磁共振(MRI)扩散峰度成像(DKI)与拉伸指数模型(SEM)评价裸鼠原位肝细胞癌(HCC)异质性

 目的   探讨磁共振(magnetic resonance imaging,MRI)扩散峰度成像(diffusion kurtosis imaging,DKI)和拉伸指数模型(stretched exponential model,SEM)评估自然生长状态下裸鼠原位肝细胞癌(hepatocellular carcinoma,HCC)空间和时间异质性的价值。方法   将25只原位HCC裸鼠模型随机分为A、B、C、D和E组,每组5只,分别于原位种植瘤生长至第21、28、35、42和49天进行1.5T MRI扫描,获得DKI和SEM以下各参数:平均峰度(mean kurtosis,MK)、平均扩散系数(mean diffusivity,MD)、扩散异质性指数α和扩散分布指数(distributed diffusion coefficient,DDC)。使用Kruskal-Wallis H 检验和Mann-Whitney U 检验比较各组间肿瘤DKI和SEM各参数的差异。使用Spearman相关分析评价DKI和SEM各参数与组织病理学上坏死分数(necrotic fraction,NF)、微血管密度(micro-vessel density,MVD)、肿瘤细胞增殖指标Ki-67指数、HE染色肿瘤最大径切面直方图异质性指标的标准差(standard deviation,SD)和峰度以及肿瘤大小之间的相关性。结果   各组间肿瘤MK、MD、α和DDC值差异均有显著统计学意义(P均<0.05)。D组肿瘤MK值明显高于A、B和E组(P均<0.05),α值明显低于A、B和E组(P均<0.05)。D组肿瘤MD和DDC值显著高于B组(P均<0.05),E组显著高于B、C组(P均<0.05)。5组肿瘤的MK值与SD和峰度值高度正相关(r=0.603和0.604,P均<0.05),α值与SD和峰度值高度负相关(r=-0.627和-0.620,P均<0.05)。从第21天至第42天肿瘤MK值与NF(r=0.587,P=0.006)、MVD(r=0.490,P=0.028)、Ki-67指数(r=0.569,P=0.009)和肿瘤大小(r=0.503,P=0.024)中度正相关,α值与NF(r=-0.577,P=0.008)、MVD(r=-0.490,P=0.028)、Ki-67指数(r=-0.574,P=0.008)和肿瘤大小(r=-0.488,P=0.029)中度负相关。从第28至第49天肿瘤MD和DDC值与NF高度正相关(r=0.706和0.664,P均<0.05),与肿瘤大小中度正相关(r=0.492和0.525,P均<0.05)。结论   DKI和SEM或可成为临床无创性评价HCC时间和空间异质性的生物影像学指标。     

先天性心脏病并发脑脓肿的影像学诊断

目的探讨影像学对先天性心脏病合并脑脓肿的诊断价值。方法回顾性分析12例先天性心脏病合并脑脓肿患者的临床资料和影像学表现,其中男8例,女4例。最小年龄15个月,最大年龄26岁,平均10岁7个月。12例均行CT检查,3例行MRI检查。结果12例患者中法洛四联症9例,肺动脉狭窄合并卵圆孔未闭1例,室间隔缺损1例,大血管转位1例。发生部位有顶叶、枕叶、顶枕叶及额顶叶。CT平扫脓肿的中心为低密度,周围可见完整或不完整的等密度环,增强扫描环壁呈明显强化。MR表现为混杂的长T1长T2信号,增强后可见厚薄较均匀一致的环形强化壁,多有分房状强化。结论先天性心脏病尤其是发绀型先心病,极易并发脑脓肿,CT及MR能够对本病作出早期诊断,有利于及时治疗,减少死亡率。     

组织多普勒成像技术对甲状腺疾病患者右室功能的评价价值

目的:探讨应用组织多普勒成像(TDI)技术评价甲状腺疾病患者右室功能的价值。方法:选取30例甲状腺功能亢进(甲亢)患者,30例甲状腺功能低下(甲低)患者,另选取30例各项检查正常者为对照。TDI模式下,将取样容积置于患者心尖四腔心切面右室侧壁三尖瓣前叶及隔叶瓣环附着处,测量心肌收缩期峰值速度(Sa)、舒张早期峰值速度(Ea)、舒张晚期峰值速度(Aa)、等容收缩时间(ICT)、射血时间(ET)、等容舒张时间(IRT),并计算Ea/Aa和右室Tei指数。结果:①3组右室侧壁Sa、Ea、Aa、Ea/Aa、ICT、IRT及右室Tei指数差异均有统计学意义(F=61.050、35.021、29.797、272.981、9.301、40.800和81.141,P均<0.05)。与对照组比较,甲亢组Sa、Aa增大,Ea/Aa、ICT减小,Tei指数增大(P均<0.05);甲低组Tei指数、IRT增大,Ea、Ea/Aa减小(P均<0.05)。②3组右室间隔壁Sa、ICT、IRT及右室Tei指数差异有统计学意义(F=55.968、18.489、34.466和29.597,P均<0.05)。与对照组比较,甲亢组Sa、Tei指数增大,ICT减小(P均<0.05);甲低组Tei指数、IRT增大(P均<0.05)。结论:TDI参数可以较好地反映甲状腺疾病患者右室功能。     

Factors Associated with Macular Staphyloma Area on Ultra-widefield Fundus Images

PurposeTo assess the feasibility of applying ultra-widefield fundus (UWF) images for macular staphyloma area (MSA) measurement and investigate the associated factors with MSA.MethodsThis is a retrospective study. MSA was measured by UWF imaging. Central foveal thickness, subfoveal choroidal thickness, subfoveal scleral thickness were measured on spectral domain optical coherence tomography. Intraclass correlation coefficients of MSA measurement would be evaluated. Multiple linear regression analysis was used to analyze the associated factors with MSA.ResultsIn total, 135 eyes of 92 patients were enrolled. The mean age was 64.73 ± 10.84 years. Mean MSA on UWF image was 279.67 ± 71.70 mm². Intraclass correlation coefficients of MSA measurement was 0.965 (95% confidence interval [CI], 0.946 to 0.977; p < 0.001). In the multiple linear regression analysis, after adjusting for subfoveal choroidal thickness, best-corrected visual acuity, central foveal thickness, and subfoveal scleral thickness, the factors independently related to MSA were axial length (β = 8.352; 95% CI, 3.306 to 13.398; p = 0.001), sex (β = −26.673; 95% CI, −51.759 to −1.586; p = 0.037), age (β = 1.184; 95% CI, 0.020 to 2.348; p = 0.046).ConclusionsIt is feasible to measure MSA on UWF image. Female, longer axial length, and older age may indicate larger MSA.     

Texture Analysis in Brain Tumor MR Imaging

Texture analysis, as well as its broader category radiomics, describes a variety of techniques for image analysis that quantify the variation in surface intensity or patterns, including some that are imperceptible to the human visual system. Cerebral gliomas have been most rigorously studied in brain tumors using MR-based texture analysis (MRTA) to determine the correlation of various clinical measures with MRTA features. Promising results in cerebral gliomas have been shown in the previous MRTA studies in terms of the correlation with the World Health Organization grades, risk stratification in gliomas, and the differentiation of gliomas from other brain tumors. Multiple MRTA studies in gliomas have repeatedly shown high performance of entropy, a measure of the randomness in image intensity values, of either histogram- or gray-level co-occurrence matrix parameters. Similarly, researchers have applied MRTA to other brain tumors, including meningiomas and pediatric posterior fossa tumors.However, the value of MRTA in the clinical use remains undetermined, probably because previous studies have shown only limited reproducibility of the result in the real world. The low-to-modest generalizability may be attributed to variations in MRTA methods, sampling bias that originates from single-institution studies, and overfitting problems to a limited number of samples.To enhance the reliability and reproducibility of MRTA studies, researchers have realized the importance of standardizing methods in the field of radiomics. Another advancement is the recent development of a comprehensive assessment system to ensure the quality of a radiomics study. These two-way approaches will secure the validity of upcoming MRTA studies. The clinical use of texture analysis in brain MRI will be accelerated by these continuous efforts.     

MR Imaging in the 21st Century: Technical Innovation over the First Two Decades

Clinical MRI systems have continually improved over the years since their introduction in the 1980s. In MRI technical development, the developments in each MRI system component, including data acquisition, image reconstruction, and hardware systems, have impacted the others. Progress in each component has induced new technology development opportunities in other components. New technologies outside of the MRI field, for example, computer science, data processing, and semiconductors, have been immediately incorporated into MRI development, which resulted in innovative applications. With high performance computing and MR technology innovations, MRI can now provide large volumes of functional and anatomical image datasets, which are important tools in various research fields. MRI systems are now combined with other modalities, such as positron emission tomography (PET) or therapeutic devices. These hybrid systems provide additional capabilities.In this review, MRI advances in the last two decades will be considered. We will discuss the progress of MRI systems, the enabling technology, established applications, current trends, and the future outlook.     

The Glymphatic System: A Review of the Challenges in Visualizing its Structure and Function with MR Imaging

The central nervous system (CNS) was previously thought to be the only organ system lacking lymphatic vessels to remove waste products from the interstitial space. Recently, based on the results from animal experiments, the glymphatic system was hypothesized. In this hypothesis, cerebrospinal fluid (CSF) enters the periarterial spaces, enters the interstitial space of the brain parenchyma via aquaporin-4 (AQP4) channels in the astrocyte end feet, and then exits through the perivenous space, thereby clearing waste products. From the perivenous space, the interstitial fluid drains into the subarachnoid space and meningeal lymphatics of the parasagittal dura. It has been reported that the glymphatic system is particularly active during sleep. Impairment of glymphatic system function might be a cause of various neurodegenerative diseases such as Alzheimer’s disease, normal pressure hydrocephalus, glaucoma, and others. Meningeal lymphatics regulate immunity in the CNS. Many researchers have attempted to visualize the function and structure of the glymphatic system and meningeal lymphatics in vivo using MR imaging. In this review, we aim to summarize these in vivo MR imaging studies and discuss the significance, current limitations, and future directions. We also discuss the significance of the perivenous cyst formation along the superior sagittal sinus, which is recently discovered in the downstream of the glymphatic system.     

肝门部神经鞘瘤一例报道及文献复习

原发于周围神经的神经鞘瘤少见,常见于头颈部和四肢的屈肌表面,位于肝门部者罕见,术前诊断困难。作者通过对1例资料完整病例的分析反相关文献复习,以期提高对神经鞘瘤的认识反诊断水平。     

光生物调节加速脑组织间液引流及其机制

目的：探讨光生物调节(photobiomodulation, PBM)对脑组织间液(interstitial fluid, ISF)引流的影响,为PBM治疗阿尔兹海默病(Alzheimer’s disease)提供新的解释。方法：24只SD雄性大鼠随机分为PBM组(n=12)、假PBM组(n=6)及空白对照组(n=6),其中PBM组根据磁示踪分子探针注射部位的不同又分为PBM同侧示踪组(n=6)和PBM对侧示踪组(n=6)。PBM组和假PBM组大鼠在脑尾状核区ISF引流到达的额叶皮层区对应的颅骨上微创暴露硬膜;PBM组使用630 nm光纤(5～6 mW/cm²)按照每次光照5 min,暂停2 min的方式,总共照射5次;假PBM组于相同位置使用光纤但不打开电源,保持相同时间;空白对照组不进行任何操作。PBM结束后,将示踪分子探针注射到每组大鼠的尾状核区,之后利用磁示踪技术根据探针分子的扩散和分布,观察大鼠尾状核区ISF引流的变化规律,并使用细胞外间隙(extracellular space, ECS)扩散参数图像(diffusion rate in ECS-map...