T1 Recovery Is Predominantly Found in Black Holes and Is Associated with Clinical Improvement in Patients with Multiple Sclerosis

BACKGROUND AND PURPOSE:Quantitative MR imaging parameters help to evaluate disease progression in multiple sclerosis and increase correlation with clinical disability. We therefore hypothesized that T1 values might be a marker for ongoing tissue damage or even remyelination and may help increase clinical correlation.MATERIALS AND METHODS:MR imaging was performed in 17 patients with relapsing-remitting MS at baseline and after 12 months of starting immunotherapy with dimethyl fumarate. On baseline images, lesion segmentation was performed for normal-appearing white matter, T2 hyperintense (FLAIR lesions), T1 hypointense (black holes), and contrast-enhancing lesions, and T1 relaxation times were obtained at baseline and after 12 months. Changes in clinical status were assessed by using the Expanded Disability Status Scale and Symbol Digit Modalities Test at both dates (Expanded Disability Status Scale-difference/Symbol Digit Modalities Test-diff).RESULTS:The highest T1 relaxation time at baseline was measured in black holes (1460.2 ± 209.46 ms) followed by FLAIR lesions (1400.38 ± 189.1 ms), pure FLAIR lesions (1327.5 ± 210.04 ms), contrast-enhancing lesions (1205.59 ± 199.95 ms), and normal-appearing white matter (851.34 ± 30.61 ms). After 12 months, T1 values had decreased significantly in black holes (1369.4 ± 267.81 ms), contrast-enhancing lesions (1079.57 ± 183.36 ms) (both P < .001), and normal-appearing white matter (841.98 ± 36.1 ms, P = .006). With the Jonckheere-Terpstra Test, better clinical scores were associated with decreasing T1 relaxation times in black holes (P < .05).CONCLUSIONS:T1 relaxation time is a useful quantitative MR imaging technique, which helps detect changes in MS lesions with time. We assume that these changes are associated with the degree of myelination within the lesions themselves and are pronounced in black holes. Additionally, decreasing T1 values in black holes were associated with clinical improvement.

MR imaging is an established tool in diagnosing multiple sclerosis and in monitoring inflammatory disease progression. In clinical routine, T2 and T1 lesion load and the detection of contrast-enhancing lesions (CE-Ls) are commonly used for monitoring subclinical disease activity and evaluating the effectiveness of pharmaceutical treatments. While hyperintense lesions on T2-weighted images (FLAIR lesions) correspond to a wide spectrum of histopathologic changes, ranging from edema and mild demyelination to glial scars or liquid necrosis, nonenhancing T1 hypointense lesions, black holes (BHs), are reported to be more specific markers for demyelination, axonal loss, and tissue damage.^1–6 It was observed that for discriminating the different stages of cell damage, the degree of BH hypointensity seems to reflect the extent of axonal loss and might distinguish demyelinated and partially remyelinated lesions.^7,8 Consequently, T1 relaxation times (T1-RTs) are increased in edema, demyelination, and axonal loss.^9–11A recent study showed that the assessment of MS lesions by their T1 values helps to increase correlations with disability and might lead to a more differentiated lesion classification.¹² However, little is known about the potential of lesional T1 values as a clinical marker in disease progression. Only a small number of previous studies have applied T1 relaxometry in patients with MS and reported increased T1 values in normal-appearing white matter (NAWM).^13,14 Therefore, our study focuses on the longitudinal evaluation of T1 values in different MS lesion types, representing different grades of tissue destruction. With the recently introduced double inversion-contrast magnetization-prepared rapid acquisition of gradient echo (MP2RAGE) sequences, it is now possible to generate quantitative T1 maps with high reproducibility.¹⁵The purpose of this study was to observe the evolution of T1 values in NAWM and in lesions in patients with MS for 1 year after starting immunotherapy with dimethyl fumarate. We hypothesized that longitudinal changes of lesional T1 values are associated with changes in clinical disability because T1 values might be a marker for ongoing tissue damage or even remyelination.     

MRI对脊髓型多发性硬化临床分期的价值

目的:探讨脊髓型多发性硬化(MS)的MRI表现及其病理基础,评价MRI对MS临床分期价值。方法:脊髓型MS患者43例,按临床特点分为急性期、静止期和缓解复发期。对所有患者行头部和脊柱磁共振检查,分析各期的MRI表现。结果:脊髓型MS的主要MRI表现为髓内长或等T1、长T2信号改变。脊髓型MS各期的MRI特点:①急性期11例,均表现为脊髓轻度~中度肿胀,增强扫描时10例(90.9%)髓内病灶有明显强化,其中9例呈斑片状或边缘环状强化,1例呈结节状强化,范围明显小于T2WI上所见;1例无强化。4例伴脊髓中央管扩张。有8例经治疗后病灶缩小,脊髓肿胀消失。②静止期17例,14例(82.4%)脊髓形态、大小未见异常,髓内病灶均无强化。③缓解复发期15例中,11例(73.3%)伴有脊髓萎缩,增强扫描时5例出现轻度点状或条状强化,病变范围与T2WI所见相似。各期脊髓型MS的病变范围及分布差异无显著性意义(P>0.05)。结论:MRI能反映脊髓型MS各期的病理变化,对脊髓型MS的分期具有重要价值。     

多发性硬化MRI诊断（附22例报告）

目的：提高对多发性硬化（MS）MRI特征的认识。材料与方法：对22例MS患者行脑和／或脊髓MRI检查，对病变的分布、形态及病变的强化进行评价。结果：脑内病变位于侧脑室周围、半卵圆中心及脑干，室旁病变其长轴多于侧脑室垂直；脊髓病变多位于颈髓及上段胸髓，呈长条状。病变急性期及活动期强化，稳定期或斑痕期不强化。结论：MRI可显示MS的特征性表现，增强扫描可提高MRI对MS早期诊断的特异性，并能对MS的病理、生理特点进行时间顺序方面的观察。     

扩散张量的三维纤维束成像在多发性硬化中的应用

目的 应用三维纤维束成像技术,研究多发性硬化(multiple sclerosis,MS)脱髓鞘斑块引起的白质纤维束的改变. 资料与方法 应用3 T 磁共振对34例MS患者和25名非MS健康志愿者行常规头颅MRI和扩散张量成像(DTI),观察MS病灶处和正常表现脑白质的纤维束变化. 结果 三维纤维束成像可以清楚显示脑内白质纤维束的方向、形态和结构.在MS斑块处可见纤维束中断、病灶远端纤维束缺失或稀少.病灶周围的纤维束表现为受压、推移改变.与相同年龄段的正常人对照,MS患者的正常表现胼胝体内纤维束稀少. 结论 基于DTI技术的纤维束成像能够直观地显示脑内白质纤维束,反映病变对纤维造成的影响.     

脑内多发性硬化的MRI诊断

目的：回顾性分析多发性硬化的ＭＲＩ特征及其对诊断与鉴别诊断的价值。材料和方法：经本院临床和随访确诊为ＭＳ的５０例患者，均行常规头颅ＭＲＩ检查，采用普通ＳＥ序列Ｔ１ＷＩ和Ｔ２ＷＩ。３６例继续行钆剂增强后ＳＥＴ１Ｗ扫描和磁化传递成像（ＭＴＩ）。结果：５０例患者脑实质内均见斑片状病灶。多数病灶位于双侧脑室旁白质及半卵圆区（４２例），其次为脑干、小脑（１４例），少数在颞叶、岛叶及顶枕叶（３例）。胼胝体轻度萎缩（１４例）及不同程度的脑萎缩（１５例）。增强后轻度强化及斑点状强化（２０例）。结论：脑内多发性硬化有较典型的ＭＲＩ表现，结合临床常可获确诊     

Clinical Feasibility of Synthetic MRI in Multiple Sclerosis: A Diagnostic and Volumetric Validation Study

BACKGROUND AND PURPOSE:Quantitative MR imaging techniques are gaining interest as methods of reducing acquisition times while additionally providing robust measurements. This study aimed to implement a synthetic MR imaging method on a new scanner type and to compare its diagnostic accuracy and volumetry with conventional MR imaging in patients with MS and controls.MATERIALS AND METHODS:Twenty patients with MS and 20 healthy controls were enrolled after ethics approval and written informed consent. Synthetic MR imaging was implemented on a Siemens 3T scanner. Comparable conventional and synthetic proton-density–, T1-, and T2-weighted, and FLAIR images were acquired. Diagnostic accuracy, lesion detection, and artifacts were assessed by blinded neuroradiologic evaluation, and contrast-to-noise ratios, by manual tracing. Volumetry was performed with synthetic MR imaging, FreeSurfer, FMRIB Software Library, and Statistical Parametric Mapping. Repeatability was quantified by using the coefficient of variance.RESULTS:Synthetic proton-density–, T1-, and T2-weighted images were of sufficient or good quality and were acquired in 7% less time than with conventional MR imaging. Synthetic FLAIR images were degraded by artifacts. Lesion counts and volumes were higher in synthetic MR imaging due to differences in the contrast of dirty-appearing WM but did not affect the radiologic diagnostic classification or lesion topography (P = .50–.77). Synthetic MR imaging provided segmentations with the shortest processing time (16 seconds) and the lowest repeatability error for brain volume (0.14%), intracranial volume (0.12%), brain parenchymal fraction (0.14%), and GM fraction (0.56%).CONCLUSIONS:Synthetic MR imaging can be an alternative to conventional MR imaging for generating diagnostic proton-density–, T1-, and T2-weighted images in patients with MS and controls while additionally delivering fast and robust volumetric measurements suitable for MS studies.

In conventional MR imaging, multiple sequences with different contrast weightings are obtained. This process is time-consuming with redundant data acquisition. Techniques such as MR fingerprinting and synthetic MR imaging can reduce acquisition times and thereby increase MR imaging availability for both clinical applications and research.^1–3 SyMRI is a synthetic MR imaging method based on a quantitative approach in which a single saturation recovery TSE sequence is used to estimate absolute physical properties, the proton density (PD), longitudinal relaxation rate, and transverse relaxation rate, including correction for B₁-inhomogeneities. Rather than predetermining acquisition parameters such as TE, TI, and TR to maximize tissue contrast,³ synthetic MR imaging produces a free range of synthetic weightings based on a single sequence through mathematic inference.^4,5 The quantitative nature of the method and its ability to probe multiple physical properties in a single sequence make it suitable for volumetric analysis.^6–10 Synthetic MR imaging has shown promising initial results for use in MS and patients with an ischemic event.^11,12 The technique is consequently gaining interest as a potentially time-efficient alternative to conventional MR imaging to visualize and quantify brain tissue properties.MS is a chronic neuroinflammatory disorder affecting 2.5 million people globally.¹³ MS has a heterogeneous clinical expression, which complicates the choice of disease-modifying therapy.¹⁴ MR imaging is a cornerstone for the diagnosis and monitoring of MS, but qualitative MR imaging measurements are poorly correlated with the clinical outcome. Volumetric MR imaging measurements have an independent predictive value in MS but require laborious image postprocessing, limiting its clinical potential.^15,16 Robust and fully automatic volumetry approved for clinical use would thus be important for clinical care and research purposes. The synthetic MR imaging technique has initially been developed for use on Philips (Best, the Netherlands) and GE Healthcare (Milwaukee, Wisconsin) MR imaging systems, but it is not available for other systems and independent evaluations of the method are scarce.^5,6The purpose of this study was to implement the synthetic MR imaging technique for use on Siemens (Erlangen, Germany) MR imaging scanners and to compare the diagnostic accuracy of synthetic and conventional images in MS. A secondary aim was to test the repeatability of the volumetric synthetic MR imaging measurements and compare the volumetric results and practicality with other commonly used brain volumetric methods.     

脑多发性硬化的MRI征象分析

目的　提高对脑多发性硬化 (MS)MRI表现特征的认识。方法　采用 0 .5T超导式磁共振仪 ,对 6 1例临床确诊的脑内MS病人行SE序列扫描 ,分析其MRI表现及特征。结果　 6 1例MS在MRI上均发现病灶。MRI对于大脑半球、小脑和脑干的病灶均能清晰显示 ,对视神经病灶显示不佳。MS病灶T1WI呈中等或低信号 ,T2 WI均为高信号。脑室旁病变其长轴多与侧脑室垂直及胼胝体的信号异常和萎缩对MS确诊起着重要作用。结论　MRI可显示MS的特征性表现 ,能发现许多CT不能发现的病灶 ,是目前诊断MS最好的影像检查方法。     

Juxtacortical Lesions and Cortical Thinning in Multiple Sclerosis

BACKGROUND AND PURPOSE:The role of juxtacortical lesions in brain volume loss in multiple sclerosis has not been fully clarified. The aim of this study was to explore the role of juxtacortical lesions on cortical atrophy and to investigate whether the presence of juxtacortical lesions is related to local cortical thinning in the early stages of MS.MATERIALS AND METHODS:A total of 131 patients with clinically isolated syndrome or with relapsing-remitting MS were scanned on a 3T system. Patients with clinically isolated syndrome were classified into 3 groups based on the presence and topography of brain lesions: no lesions (n = 24), only non–juxtacortical lesions (n = 33), and juxtacortical lesions and non–juxtacortical lesions (n = 34). Patients with relapsing-remitting MS were classified into 2 groups: only non–juxtacortical lesions (n = 10) and with non–juxtacortical lesions and juxtacortical lesions (n = 30). A juxtacortical lesion probability map was generated, and cortical thickness was measured by using FreeSurfer.RESULTS:Juxtacortical lesion volume in relapsing-remitting MS was double that of patients with clinically isolated syndrome. The insula showed the highest density of juxtacortical lesions, followed by the temporal, parietal, frontal, and occipital lobes. Patients with relapsing-remitting MS with juxtacortical lesions showed significantly thinner cortices overall and in the parietal and temporal lobes compared with those with clinically isolated syndrome with normal brain MR imaging. The volume of subcortical structures (thalamus, pallidum, putamen, and accumbens) was significantly decreased in relapsing-remitting MS with juxtacortical lesions compared with clinically isolated syndrome with normal brain MR imaging. The spatial distribution of juxtacortical lesions was not found to overlap with areas of cortical thinning.CONCLUSIONS:Cortical thinning and subcortical gray matter volume loss in patients with a clinically isolated syndrome or relapsing-remitting MS was related to the presence of juxtacortical lesions, though the cortical areas with the most marked thinning did not correspond to those with the largest number of juxtacortical lesions.

Multiple sclerosis is a chronic, persistent inflammatory-demyelinating disease of the central nervous system, characterized pathologically by focal areas of inflammation, demyelination, axonal loss, and gliosis. Brain MR imaging typically shows multifocal lesions, mainly in white matter regions,¹ though focal cortical demyelinated plaques are also a prominent feature, even in the earliest phases of the disease.² Unfortunately, conventional MR imaging has limited sensitivity for detecting cortical lesions because of their small size, the poor contrast resolution, and the partial volume effects of the subarachnoid spaces and surrounding cortex.^3,4 Thus, histopathologic studies are the only way to describe, quantify, and classify gray matter lesions according to their position in relation to the gray-white matter surface (leukocortical or juxtacortical; intracortical and subpial).^5,6 Despite the limited sensitivity of MR imaging for detecting cortical lesions in MS, results of several studies showed that cross-sectional cortical lesion volume and its increase over time are associated with progression of disability and cognitive impairment in MS.^7–10Brain atrophy, which is also frequently detected by MR from the earliest stages of MS, is associated with irreversible neurologic disability, including cognitive impairment.^11–14 Whole-brain atrophy has emerged as a clinically relevant component of disease progression, and results of several studies showed that this parameter correlates better with disability and, in particular, with cognitive impairment than with focal lesions.¹⁵ Although most brain atrophy measurements are based on global or regional (gray and white matter) brain volume assessment, cortical thickness has recently emerged as a new way to assess cortical gray matter atrophy because decreased thickness is related to fatigue, disability in general, and cognitive impairment in particular.^13,16 This measurement seems to be dependent on focal white matter lesion volume,¹⁷ but a potential relationship between the presence and location of demyelinating juxtacortical lesions (JLs) and cortical atrophy has not been elucidated. Therefore, the aim of this study was to explore the role of JLs on cortical atrophy and to investigate whether their presence is related to local cortical thinning in the early stages of MS.     

脊髓多发性硬化的MRI诊断

目的 提高对脊髓多发性硬化的MRI诊断水平。材料与方法 对14例脊髓多发性硬化病变的部位、范围、病变处脊髓形态、MR信号及强化程度进行分析评价。结果 脊髓多发性硬化的特征性MRI表现为：主要发生在颈段脊髓,病变平均为5个椎体长度,急性期病变局部脊髓肿胀,病变呈斑片状,T1WI呈低或等信号,T2WI呈高信号,静脉注射Gd-DTPA后病变呈斑片状或边缘强化。经激素正规治疗后病变脊髓恢复正常,强化程度减弱或无强化。结论 MRI不仅有助于脊髓多发性硬化的诊断,而且有助于与其他脊髓内病变的鉴别诊断。     

伴多脏器损害的结节性硬化症临床表现与影像学诊断价值

目的探讨伴多脏器损害结节性硬化症的临床特点与影像学诊断价值。方法收集本院2例和相关文献27例结节性硬化症,分析其临床表现,多器官损害的范围和类别及其影像学表现。结果29例中男17例,女12例。平均年龄16.8岁。有家族史6例。癫痫25例伴智力低下15例。面部对称性血管纤维瘤22例,同时伴体表其它部位类似改变3例。指(趾)甲下纤维瘤4例。拇指多指畸形2例。腹部肿块7例伴血尿4例。室管膜下结节硬化27例。肾脏病变17例,伴有肝病变9例,脾病变5例。X线检查:肺囊性变2例,多骨密度增高灶疑骨转移2例。结论结节性硬化症可累及多脏器,影像学检查以脑室管膜下钙化和肾错构瘤最具定性价值。     

复发-缓解型多发性硬化的磁共振波谱表现

目的 探讨复发-缓解型多发性硬化(relapsing-remitting muldple sclerosis,RRMS)的磁共振波谱(MRS)表现,提高其诊断水平.方法 收集本院经临床确诊的多发性硬化24例的MRS影像学资料,回顾分析其MRS特点.结果 24例急性期均可见明显的NAA峰及NAA/Cr减低,伴随着NAA峰减低,其中22例有明显的Cho峰增加,16例Lac峰增加,其中4例出现明显的Cr峰减低,6例出现较为明显的Lip峰和mI峰;在急性期过后的数天至数周内,本组病例中5例原减低的NAA有所恢复,其余19例均持续减低达数月,Cho、Cr及Lip峰逐渐恢复至正常水平,mI峰持续增加达数月.结论 RRMS的MRS表现具有一定的特点,它对早期发现多发性硬化具有一定的意义,与传统MRI相结合可以提高RRMS的诊断率.     

多发硬化MRI减影伪影的初步研究

目的对多发硬化MRI减影伪影进行定义和分类.材料和方法在31例MS患者MRI减影图像中,盲法对10例MS扫描和再扫描的(扫描间隔30min)321个病灶进行分析,对MRI减影伪影进行定义.根据图像像素移动方向,对比原始图像和再排列图像进行MRI减影伪影分类.结果MRI减影伪影是在MRI减影图像上,病灶边缘出现的一种局限的、亮暗对称的异常信号区,可分为1类(12个,占15.1%)、2类(4个,占5.1%)、3类(42个,占53.2%)和4类(21个,占26.6%).在321个病灶中,79个MS病灶有MRI减影伪影,占总病灶的24.6%.结论对MRI减影伪影识别有较好的重复性,正确鉴别MRI减影伪影有利于提高探测多发硬化斑块的变化.