PD/T2 WI和FLAIR序列对多发性硬化患者病灶的对比研究

目的 研究不同MR扫描序列对多发性硬化(MS)患者病灶检出率的差异.资料与方法将符合2001年McDonald MS诊断标准且资料完整的74例有脑部病灶的MS患者纳入研究对象,采用国际MS中心推荐的MR扫描序列,比较液体衰减反转恢复(FLAIR)和质子密度双回波(PD/T2WI)序列对MS病灶的显示差别.结果 (1)皮质及皮质下病灶,FLAIR较T2WI的检出率差异有统计学意义(P＜0.05);幕下病灶,PD/T2WI较FLAIR的检出率稍高,但差异无统计学意义(P＞0.05);侧脑室周围以及深部白质区病灶的检出率比较,FLAIR、T2WI和PD之间差异无统计学意义(P＞0.05).(2)进展型MS较复发-缓解型MS幕上皮质的病灶数差异有统计学意义(P＜0.05).结论不同的扫描序列对MS患者不同部位的病灶检出率各有差异,针对受检部位选择合适的序列,可提高对病灶的检出率.     

多发性硬化患者脑灰质损害的MRI表现及扩散张量成像定量研究

目的 分析多发性硬化(MS)患者脑灰质病灶的MRI特征及表现正常的脑灰质(NAGM)是否存在隐匿性损伤.方法 对34例临床确诊的MS患者(MS组)和25名健康志愿者(对照组)行常规头颅MRI和扩散张量成像(DTI),观察MS的脑灰质病灶特征,测量深部灰质核团的平均扩散率(ADC)和各向异性分数(FA),采用非配对t检验比较两组间是否存在差异.结果 MR检查发现MS的脑灰质病灶共83个,占全部病灶(443个)的18.7%.分布以额叶最多,其次是颞叶与丘脑.大多数病灶呈圆形或类圆形,其中T2WI发现灰质病灶60个,液体衰减反转恢复(FLAIR)序列T2WI发现病灶78个,其中71个病灶呈高或稍高信号,3个病灶呈中心低、周围稍高的环形改变,4个呈低信号.扩散加权成像(DWI)发现高信号或低信号病灶36个,其中有9个小病灶在DWI呈明显高信号.其余病灶呈等信号而不能被发现.MS组尾状核头、壳核、丘脑的ADC值分别为(8.0±0.7)、(7.4 ±0.5)、(7.7±0.4)×10-4mm2/s,均高于对照组[分别为(7.4±0.6)、(7.0 ±0.5)、(7.2±0.7)×10-4mm2/s],差异具有统计学意义(t值分别为-3.079、-2.564、-2.722,P值均<0.05).结论 MS的脑灰质病灶在常规MRI和DWI上的表现有一定的特征,FLAIR联合DWI可提高病灶的检出,DTI可以反映出NAGM内的隐匿性损害.     

磁化传递成像观察多发性硬化大鼠中枢神经系统病灶

目的：探索应用3.0T临床型MR设备进行磁化传递成像（MTI）观察多发性硬化（MS）大鼠中枢神经系统病灶的可行性。方法：用髓鞘少突胶质细胞糖蛋白多肽35-55（MOG35-55）致敏Lewis大鼠制备MS动物模型实验性自身免疫性脑脊髓炎（EAE）大鼠10只,正常对照组大鼠4只。3.0T临床型MR扫描仪配备小正交腕关节线圈,分别对大鼠脑和脊髓行T2W、T1磁化传递和T1非磁化传递三维容积扫描。利用工作站专业软件获得磁化传递率（MTR）图像。结果：成功建立MOG35-55-EAE模型大鼠10只。大鼠脑和脊髓的MTR图像具有较高的空间分辨率和对比度。MOG35-55-EAE病灶在T2WI上呈高信号,在MTR图像上表现为MTR值下降,呈低信号,在T1WI上呈低信号或者等信号。MTR图像对MOG35-55-EAE病灶检出率高,病灶显示清晰。对照组大鼠MR扫描未见异常。结论：应用3.0T临床型MR设备可以获得高质量的MOG35-55-EAE大鼠脑和脊髓MTR图像。MTI有望成为小动物中枢神经系统脱髓鞘疾病实验研究的体外监测手段。     

低场磁共振FLAIR序列对多发性硬化的评价

目的：探讨低场磁共振FLAIR序列在多发性硬化诊断中的价值。方法：收集27例多发性硬化患者，使用0．2TMR扫描仪，对比分析常规T1WI、T2WI及序列在检出多发性硬化病灶及其边界方面的敏感性。结果：序列对多发性硬化检出及明确病灶边界的敏感性高于T2WI和T1WI，经统计分析有显著性意义（P〈0．05），但有的部位不如常规T2WI。结论：多发性硬化的低场MRI诊断．FLAIR序列是最有价值的检查方式之一，FLAIR优点较多，但二种序列应互为补充。     

巨噬细胞活性MRI对多发性硬化大鼠模型中枢神经系统病灶诊断价值的初步研究

目的 探讨巨噬细胞活性成像(MAI)对多发性硬化(MS)模型大鼠脑和脊髓病灶的诊断价值.方法 20只正常Lewis大鼠用数字表法随机分成实验组15只,对照组5只.应用髓鞘少突胶质细胞糖蛋白多肽35-55(MOG35-55)致敏实验组大鼠制备MS动物模型实验性自身免疫性脑脊髓炎(EAE),大鼠首次急性发病后第3天行MR检查.分别对大鼠脑和脊髓行T2WI、T1WI和Gd-DTPA增强T1WI的三维容积扫描.经大鼠尾静脉注入超微超顺磁性氧化铁(USPIO)24 h后行USPIO增强T2WI(即MAI).利用工作站专业软件获得大鼠脑和脊髓冠状面、横断面和矢状面的重组图像,并与常规图像进行比较.结果 成功建立MOG35-55-EAE模型大鼠15只.MOG35-55-EAE大鼠急性发病期相关的中枢神经系统病灶多数分布在脑内(58/63),少数位于脊髓(5/63).常规MRI上病灶表现为T2WI高信号、T1WI低信号,部分出现Gd-DTPA强化.在MAI图像上病灶呈低信号,部分USPIO强化病灶在T2WI上呈等信号,病灶的USPIO强化与Gd-DTPA强化表现不完全一致.T2WI(14/15)和MAI(13/15)对MOG35-55-EAE大鼠急性期病灶的敏感度高,两者联合对病灶的检出率高达100%(15/15),增强T1WI的敏感度相对较低(7/15).对照组大鼠MAI未见异常.结论 MAI弥补传统MR检查技术的不足,能监测EAE的炎症反应,与常规T2WI联合能提高MOG35-55-EAE大鼠病灶的检出率;Gd-DTPA增强能显示EAE血脑屏障破坏的早期活动性病灶,MAI与之联合成像对EAE病灶的诊断和监测有互补作用.     

多发性硬化两类MRI异常信号的分析

目的：探讨多发性硬化（ＭＳ）两类ＭＲＩ异常信号的诊断意义及其与病理改变之关系。方法：采用超导式磁共振成像系统对１６例ＭＳ行自旋回波（ＳＥ）序列扫描，其中３例经尸检获组织学诊断者行ＭＲＩ－病理对照研究。结果：３例尸检病例显示有ＭＳ斑块状、非斑块状长Ｔ２信号，其病理基础除ＭＳ硬化斑外，还可见坏死软化灶、空洞形成，以及斑块旁的小血管损害、铁沉积。与斑块状长Ｔ２信号并存的短Ｔ２低信号对称性分布于壳核、丘脑，见于９例病程相对较长的慢性病例。结论：ＭＳ长Ｔ２信号的病理基础除经典的斑块病灶外，还有坏死软化灶及空洞形成；短Ｔ２低信号可能与血管损害、铁沉积有关。     

多发性硬化脑内病灶的扩散张量成像

目的研究多发性硬化(MS)的脑内病灶在磁共振扩散张量成像(DTI)上的主要特征,量化分析不同时期病灶的ADC值的差异,探讨DTI在反映MS病理变化中的价值。方法应用3.0 T磁共振设备对34例MS病人行常规头颅MRI和DTI检查,根据病灶有无强化和在T1WI上的信号强度,进行急慢性期病灶的分组。分析不同时期MS病灶在DTI后处理所获得的DWI、ADC、FA图上的特征,并测量各组病灶的ADC值。结果35个急性期病灶中的33个病灶(94.3%)于DWI上呈高信号,5个环形强化病灶在DWI上亦呈环形高信号。急、慢性期病灶的ADC值均升高。慢性期病灶的ADC值明显高于急性期病灶[(12.43±3.78)×10-4 mm2/s∶(10.10±2.28)×10-4 mm2/s,P=0.001]。急性期环形强化病灶的ADC值较非环形强化病灶的高,慢性期T1WI低信号病灶的ADC值较T1WI等信号病灶的高,T1WI明显低信号病灶的ADC值最高。急、慢性期病灶的FA值均降低。FA图能够清晰显示纤维通路上的病灶和纤维束的中断,定位上明显优于常规MRI。病灶于FA图上显示的范围较常规MRI T2WI上显示的大。结论DTI可以反映MS不同时期病灶的病理变化,为观测疾病演变和评价临床疗效提供有效的指标。     

多发性硬化脑内病灶的扩散张量成像

目的 研究多发性硬化(MS)的脑内病灶在磁共振扩散张量成像(DTI)上的主要特征,量化分析不同时期病灶的ADC值的差异,探讨DTI在反映MS病理变化中的价值.方法 应用3.0T磁共振设备对34例MS病人行常规头颅MRI和DTI检查,根据病灶有无强化和在T1WI上的信号强度,进行急慢性期病灶的分组.分析不同时期MS病灶在DTI后处理所获得的DWI、 ADC、 FA图上的特征,并测量各组病灶的ADC值.结果 35个急性期病灶中的33个病灶(94.3%)于DWI上呈高信号,5个环形强化病灶在DWI上亦呈环形高信号.急、慢性期病灶的ADC值均升高.慢性期病灶的ADC值明显高于急性期病灶[(12.43.±3.78)×10-4mm2/s: (10.10±2.28×10-4mm2/s, P=0.001].急性期环形强化病灶的ADC值较非环形强化病灶的高,慢性期T1WI低信号病灶的ADC值较T1WI等信号病灶的高,T1WI明显低信号病灶的ADC值最高.急、慢性期病灶的FA值均降低.FA图能够清晰显示纤维通路上的病灶和纤维束的中断,定位上明显优于常规MRI.病灶于FA图上显示的范围较常规MRI T2WI上显示的大.结论 DTI可以反映MS不同时期病灶的病理变化,为观测疾病演变和评价临床疗效提供有效的指标.     

多发性硬化颈髓病变磁化传递成像的临床应用

目的探讨3.0T磁共振扫描仪(Siemens Trio Tim)磁化传递成像(MTI)在多发性硬化(MS)颈髓病变中的应用价值及其与临床的关系。资料与方法对11例伴颈髓病变的MS患者和20名健康自愿者行颈髓常规MRI和MTI。测量健康自愿者C2～7水平、MS患者MS斑块及正常表观颈髓(NACC)的磁化传递率(MTR),对其进行对照研究,并分析MTR与扩展病残状态评分(EDSS)之间的相关性。结果健康自愿者颈髓平均MTR值为(27.12±0.27)%,C2～7水平间颈髓MTR值差异无统计学意义(P>0.05)。MS斑块组、NACC组及对照组间的MTR值差异均具有统计学意义(P<0.05)。MS斑块组的MTR值与EDSS值存在高度负相关(r=-0.754,P=0.007)。结论颈髓MTI能发现MS患者T2WI病灶以外的隐匿性损伤,为判断损害程度提供信息。     

多发性硬化的临床与磁共振成像和CT诊断

目的：探讨多发性硬化（MS）的临床及影像特点,旨在减少误诊率,提高诊断准确率。方法统计近10年内明确诊断的9例多发性硬化患者的临床资料及影像检查表现。9例患者均于日本东芝系统Vantage XGV 1．5 T超导型核磁共振扫描仪上检查。CT扫描用德国西门子公司生产的Emation 6排多层螺旋CT机器,从颅底向颅顶连续扫描。结果多发性硬化好发年龄平均31．5岁（和之前文献报道一致）,MRI检查敏感率超过CT,好发部位,9例中5例于脑内,2例发生于脊髓,2例脑与脊髓同时存在病灶。结论 MS年龄多在20~40之间。临床分为脑型、脊髓型、和脑脊髓型。通过临床及影像分析,降低了MS的误诊率。     

Lesion detection at seven Tesla in multiple sclerosis using magnetisation prepared 3D-FLAIR and 3D-DIR

Objectives  

To examine the feasibility and value of 7 T 3D T2-weighted Fluid Attenuated Inversion Recovery (FLAIR) and Double Inversion Recovery (DIR) MR sequences for lesion detection in multiple sclerosis (MS).     

Improved in vivo detection of cortical lesions in multiple sclerosis using double inversion recovery MR imaging at 3 Tesla

Objective

To investigate the impact of a higher magnetic field strength of 3 Tesla (T) on the detection rate of cortical lesions in multiple sclerosis (MS) patients, in particular using a dedicated double inversion recovery (DIR) pulse sequence.

Methods

Thirty-four patients with clinically isolated syndromes or definite MS were included. All patients underwent magnetic resonance imaging (MRI) at 1.5 T and 3 T, including T2-weighted turbo spin echo (TSE), fluid-attenuated inversion recovery (FLAIR) and DIR sequences. All images were analysed for focal lesions categorised according to their anatomical location.

Results

The total number of detected lesions was higher at 3 T across all pulse sequences. We observed significantly higher numbers of lesions involving the cortex at 3 T using a DIR sequence. DIR at 3 T showed 192% more pure intracortical (p?<?0.001) and 30% more mixed grey matter-white matter lesions (p?=?0.008). No significant increase in cortical lesions could be detected on the FLAIR and T2-weighted images. Using the T2-weighted and FLAIR sequences, significantly more lesions could be detected at 3 T in the infratentorial, periventricular and juxtacortical white matter.

Conclusion

DIR brain MR imaging at 3 T substantially improves the sensitivity of the detection of cortical lesions compared with the standard magnetic field strength of 1.5 T.     

Focal cortical lesion detection in multiple sclerosis: 3 Tesla DIR versus 7 Tesla FLASH-T2

Purpose:

To evaluate the inter‐rater agreement of cortical lesion detection using 7 Tesla (T) FLASH‐T2* and 3T DIR sequences.

Materials and Methods:

Twenty‐six patients with multiple sclerosis were scanned on a human 7T (Siemens) and 3T MRI (TIM Trio, Siemens) to acquire 3T DIR/MEMPR and 7T FLASH‐T2* sequences. Four independent reviewers scored and categorized cortical lesions in the bilateral precentral gyri (motor strips) as leukocortical, intracortical, or subpial. Inter‐rater agreement was assessed according to lesion category using the kappa statistic. The sensitivity of recent MAGNIMS consensus guidelines for cortical lesion detection using 3T DIR was assessed with 7T FLASH‐T2* as the reference gold standard.

Results:

Inter‐rater agreement at 7T was excellent compared with 3T (k = 0.97 versus 0.12). FLASH‐T2* at 7T detected subpial lesions while 3T DIR did not. The predicted sensitivity of 3T DIR sequence for cortical lesions in vivo is modest (range of 13.6 to 18.3%).

Conclusion:

The 7T FLASH‐T2* detects more cortical—particularly subpial—lesions compared with 3T DIR. In the absence of DIR/postmortem data, 7T FLASH‐T2* is a suitable gold‐standard instrument and should be incorporated into future consensus guidelines. J. Magn. Reson. Imaging 2012;537‐542. © 2011 Wiley Periodicals, Inc.     

3 Tesla and 7 Tesla MRI of multiple sclerosis cortical lesions

Cortical lesions are prevalent in multiple sclerosis but are poorly detected using MRI. The double inversion recovery (DIR) sequence is increasingly used to explore the clinical relevance of cortical demyelination. Here we evaluate the agreement between imaging sequences at 3 Tesla (T) and 7T for the presence and appearance of individual multiple sclerosis cortical lesions. Eleven patients with demyelinating disease and eight healthy volunteers underwent MR imaging at 3T (fluid attenuated inversion recovery [FLAIR], DIR, and T(1)-weighted magnetization prepared rapid acquisition gradient echo [MP-RAGE] sequences) and 7T (T(1)-weighted MP-RAGE). There was good agreement between images for the presence of mixed cortical lesions (involving both gray and white matter). However, agreement between imaging sequences was less good for purely intracortical lesions. Even after retrospective analysis, 25% of cortical lesions could only be visualized on a single MRI sequence. Several DIR hyperintensities thought to represent cortical lesions were found to correspond to signal arising from extracortical blood vessels. High-resolution 7T imaging appeared useful for confidently classifying the location of lesions in relation to the cortical/subcortical boundary. We conclude that DIR, FLAIR, and MP-RAGE imaging sequences appear to provide complementary information during the detection of multiple sclerosis cortical lesions. High resolution 7T imaging may facilitate anatomical localization of lesions in relation to the cortical boundary.     

Comparison of multiple sclerosis lesions at 1.5 and 3.0 Tesla

OBJECTIVE: To evaluate the relative sensitivity of MR scanning for multiple sclerosis (MS) at 1.5 Tesla (T) and 3.0 T using identical acquisition conditions, as is typical of multicenter clinical trials. METHODS: Twenty-five subjects with MS were scanned at 1.5 T and 3.0 T using fast spin echo, and T(1)-weighted SPGR with and without gadolinium contrast injections. Image data, blinded to field strength, were analyzed using automated segmentation and lesion counting. RESULTS: Relative to scanning at 1.5 T, the 3.0 T scans showed a 21% increase in the number of detected contrast enhancing lesions, a 30% increase in enhancing lesion volume and a 10% increase in total lesion volume. DISCUSSION: The improved detection ability using high-field MR imaging is prominent even when sequence parameters are optimized around the midfield units. Multicenter trials using both 1.5 T and 3.0 T instruments may be affected by these sensitivity differences.     

Cerebral cortical lesions in multiple sclerosis detected by MR imaging at 8 Tesla

BACKGROUND AND PURPOSE: Conventional imaging of ex-vivo brain at 1.5T in multiple sclerosis (MS) detects only a small fraction of the gray matter cerebral cortical lesions that can be detected by pathology. Our purpose was to examine if imaging at 8T can detect plaques in cortical gray matter (CGM) not evident at 1.5T. METHODS: An ex-vivo brain obtained at autopsy from a patient with MS was formalin fixed and 1 cm coronal slices were examined using MR imaging at 8T. RESULTS: Numerous cerebral cortical lesions not evident at 1.5T were seen at 8T. Lesions were easily identified using gradient-echo and spin-echo (SE) as well as diffusion images. MR imaging at 8T identified many of the types of plaques previously evident only by pathology. The magnitude of the cortical involvement in this 1 patient was severe. Lesions in the gray matter readily visible by high-field MR imaging were sometimes barely visible by pathology. MR imaging at 8T often facilitated the detection of such plaques by pathology. CONCLUSION: This study establishes the utility of high-field imaging at 8T in the delineation of plaques in the cerebral CGM in MS.     

Conventional MRI and magnetisation transfer imaging of tumour-like multiple sclerosis in a child

Tumefactive multiple sclerosis is a rare entity in children. Differential diagnosis includes other mass lesions such as neoplasm and abscess. A case of tumefactive multiple sclerosis in a child is presented. The open-ring pattern of enhancement on conventional MRI and magnetisation transfer imaging was important for the initial diagnosis and the evaluation of the course of the disease.     

Central trigeminal involvement in multiple sclerosis using high-resolution MRI at 3 T

Trigeminal neuralgia and sensory disturbance is common in multiple sclerosis (MS). Recent literature suggests that signal abnormalities in the cisternal trigeminal nerve and pontine root entry zone are seen in approximately 3% of MS patients, using conventional diagnostic MRI. The objective of this study was to determine the prevalence of trigeminal lesions using high-resolution MRI at 3T. Forty-seven patients with clinically definite MS, chosen at random from the outpatient population of a neuroscience centre underwent MRI on a Siemens 3T Trio machine. Three 3D sequences of T2 TSE (turbo spin echo), T2 FLAIR (fluid attenuated inversion recovery) and T1 IR (inversion recovery) were acquired in the coronal plane. The sequences were of contiguous 1 mm slices with in-plane resolution of up to 0.5 mm by 0.5 mm. Images were read by both a neurologist and a neuroradiologist. Any clinical history of trigeminal symptoms was determined for all subjects. The results showed that 11 patients (23%) had high signal in the trigeminal root entry zone and either the trans-cisternal nerve or pontine nucleus; example images are given. MRI changes did not correspond to clinical symptoms (chi square probability 1.000). The study concludes that high-resolution MRI at 3T yielded a high prevalence of detectable trigeminal abnormality in the MS sample studied. MRI involvement did not correspond to trigeminal symptoms.Both facial pain (including trigeminal neuralgia) and non-painful facial sensory disturbance are routinely encountered in patients with multiple sclerosis (MS). Previous studies suggest that the prevalence of trigeminal lesions is between 3% and 7% [1, 2], and such lesions may or may not be related to clinical symptoms [1–5]. The relationship between trigeminal sensory symptoms and trigeminal lesions remains unclear. The use of thin, contiguous slices and higher field strength, which improves signal to noise ratio (SNR), may yield greater detection of abnormalities [6–8]. A prospective study was therefore undertaken to determine the prevalence of central trigeminal lesions in MS, using high-resolution MRI at 3 T, and the relation between the presence of lesions and facial sensory symptoms.     

Optimizing PRESS localized citrate detection at 3 Tesla.

Analytical methods are used to characterize the response of the strongly coupled two-spin system of citrate to point-resolved spectroscopy (PRESS)-based sequences at 3 T. The signal output is analyzed line by line, as well as in the Cartesian product operator basis. Patterns with a periodicity of 80.9 ms are identified. Furthermore, it is shown that at TE = n . 80.9 ms (n in {0,1,2,...}), the spin evolution can be described without direct reference to strong coupling terms. The theoretical results are found to be in good agreement with in vivo experiments. These results can be used to design protocols for prostate MRS and MRSI at 3 T, and give guidelines for optimizing spin-echo-based acquisition schemes for detecting two-spin systems at arbitrary field strengths.     

Imaging endolymphatic hydrops at 3 tesla using 3D-FLAIR with intratympanic Gd-DTPA administration.

PURPOSE: Visualization of endolymphatic hydrops by 3-dimensional fluid-attenuated inversion recovery-FLAIR using conventional turbo-spin-echo (3D-FLAIR-CONV) after intratympanic injection of Gd-DTPA has been reported in patients with Ménière's disease. Compared to 3D-FLAIR-CONV used in previous studies, the addition of a variable flip-angle technique (3D-FLAIR-VFL) enables very long echo trains and, therefore, shorter scan times. We evaluated whether 3D-FLAIR-VFL could replace 3D-FLAIR-CONV in detecting endolymphatic hydrops after intratympanic Gd-DTPA administration. METHODS: Eleven patients were included in this study. Twenty-four hours after Gd-DTPA injection, we performed 3D-FLAIR-CONV and 3D-FLAIR-VFL imaging at 3T. We compared the contrast-to-noise ratio (CNR) between cochlear fluid and the cerebellum between the 2 FLAIR sequences. We subjectively scored the size of the endolymphatic space in the cochlea and vestibule for each patient and correlated the scores with the clinical diagnoses. RESULTS: The CNR of 3D-FLAIR-CONV was significantly higher than that of 3D-FLAIR-VFL. Scores for the size of endolymphatic space in the vestibule were identical between the 2 sequences; however, those in the cochlea disagreed in 3 cases. 3D-FLAIR-CONV correlated better with the clinical diagnoses. CONCLUSIONS: Currently, we may not be able to replace 3D-FLAIR-CONV with 3D-FLAIR-VFL, at least not with the scanning parameters used in the present study.