快速液体衰减翻转恢复脉冲序在颅脑MRI的应用

目的：探讨快速液体衰减翻转恢复序列在颅脑中ＭＲＩ中的临床应用价值。材料与方法：对本组３３例经ＦａｓＦＬＡＩＲ序列及常规ＳＥ序列扫描的病例进行对比分析。并结合文献讨论了ＦａｓｔＦＬＡＩＲ序列的原理、图像特点及临床应用价值。结果：ＦａｓｔＦＬＡＩＲ显示病变为９７．８０％,常规ＳＥ序列为８３．５２％;内部结构与边缘情况均显示良好者,ＦａｓｔＦＬＡＩＲ序列为１９．７８％,常规ＳＥ序列为７．６９％。二者在显     

T2W液体衰减反转恢复序列MRI在中枢神经系统的临？…

本文介绍液体衰减反转恢复序列在中枢神经系统各种不同病变的诊断价值，包括缺血慎重中风、脱髓鞘疾病、脑膜炎、颅脑外伤、囊性病变、实性肿瘤、血管畸形及蛛网膜下腔出血等。也讨论了液体衰减的反转恢复在应用中的限制。     

磁共振快速液体衰减反转恢复序列对亚急性和慢性蛛网膜下腔 …

目的 研究ＭＲ快速液体衰减反转恢复（ＦＬＡＩＲ）序列诊断亚急性和慢性蛛网膜下腔出血（ＳＡＨ）的价值。方法 ３０例头部健康者和１７例次ＳＡＨ患者在发病后第４￣３５天进行头部ＭＲＩ检查。扫描机为０．５Ｔ超导ＭＲ机。观察亚急性和慢性ＳＡＨ在ＦＬＡＩＲ的信号表现,并与同期ＣＴ和常规ＭＲＩ所见比较。再对４６个正常和病变的ＦＬＡＩＲ图像做双盲比较分析,以评价其诊断可靠性。结果 ＦＬＡＩＲ成像显示亚急性和慢性Ｓ     

快速液体抑制反转恢复脉冲序列在脑挫裂伤中的应用

目的探讨快速液体抑制反转恢复脉冲序列(FastFLAIR)在脑挫裂伤诊断中的应用价值.材料与方法回顾性分析36例脑挫裂伤患者的MR表现,对FastFLAIR、T2W/TSE及T1W/SE三种序列进行比较.结果在36例脑挫裂伤患者中FLAIR显示病灶较T2WI清晰者28例,在经过腰穿或CT检查证实合并有蛛网膜下腔出血的29例患者中,FLAIR序列可100%明确诊断,而T1WI明确诊断的仅11例(占37.9%).结论对脑挫裂伤病灶的显示及蛛网膜下腔出血的诊断FLAIR具有重要价值.     

快速液体衰减翻转恢复脉冲序列在颅脑MRI的应用

目的：探讨快速液体衰减翻转恢复序列（ＦａｓｔＦＬＡＩＲ）在颅脑ＭＲＩ中的临床应用价值。材料与方法：对本组３３例经ＦａｓｔＦＬＡＩＲ序列及常规ＳＥ序列扫描的病例进行对比分析,并结合文献讨论了ＦａｓｔＦＬＡＩＲ序列的原理、图像特点及临床应用价值。结果：ＦａｓｔＦＬＡＩＲ显示病变为９７．８０％（８９／９１）,常规ＳＥ序列为８３．５２％（７６／９１）;内部结构与边缘情况均显示良好者,ＦａｓｔＦＬＡＩＲ序列为１９．７８％（１８／９１）,常规ＳＥ序列为７．６９％（７／９１）。二者在显示病变方面有显著差异（０．０１＜Ｐ＜０．０５）。ＦａｓｔＦＬＡＩＲ序列在显示小病灶及脑表病灶、脑室内病灶方面优于常规ＳＥ序列。结论：ＦａｓｔＦＬＡＩＲ序列在显示病变方面更敏感,且能获得更多病理信息。     

增强FLAIR序列在颅脑病变中的应用

目的评价增强FLAIR序列在颅脑疾病诊断中的应用.材料与方法50例患者行脑MRI平扫(T1 WI、T2 WI、FLAIR)和Gd-DTPA增强(FLAIR和T1WI)检查,双盲法比较增强前后FLAIR与T1 WI的差异.结果所有病变在FALIR均显示不同程度的异常增强,在脑梗塞疾病中增强FLAIR诊断敏感性大于增强T1 WI.星形细胞瘤、转移瘤和结核瘤,T1 WI增强优于FLAIR.结论增强FLAIR在检查脑表面病变,如皮质或皮质下梗塞,诊断准确性高于增强T1 WI.     

低场FLAIR技术在脑梗塞MRI诊断中的应用

液体衰减翻转恢复序列(FLUID INVERSION RECOVERY简称FLAIR)，这种重T2W反转恢复技术使脑脊液这样的液体无信号，这样在黑色脑脊液和低信号强度的脑白质的对比下，脑室周围脑白质的微细病变显得更突出。     

MRI快速FLAIR技术在脑梗死诊断中的应用

目的:评价快速液体衰减反转恢复(FLAIR)技术在脑梗死诊断中的临床应用价值。方法:150例脑梗死患者,均行常规TSE序列T2WI及快速FLAIR序列检查,对比、分析两种序列成像对梗死灶的显示能力。结果:磁共振多序列检查共发现梗死灶1103个,FLAIR序列显示1056个,达95.74%;T2WI序列显示937个,达84.95%,二者有显著性差异(P<0.005)。FLAIR序列较T2WI序列多显示的135个梗死灶多分布在大脑皮层、灰白质交界区及侧脑室周围;全部病灶中31个超急性期梗死灶和16个位于脑干区的其他期梗死灶FLAIR序列未能显示;FLAIR序列显示急性及亚急性期梗死灶呈高信号,慢性期梗死灶呈低、高混杂信号及中心区低信号、周边高信号,T2WI序列则全部显示为高信号;同时47例患者于两侧基底节区的VR腔隙,FLAIR序列显示为边界清晰的低信号,周围正常脑组织信号。结论:FLAIR序列对于显示靠近脑表面及侧脑室周围的梗死灶,以及鉴别新、旧梗死灶及鉴别腔隙性梗死灶与VR腔隙明显优于常规T2WI序列。     

液体衰减翻转恢复序列在颅脑MRI中的应用

目的：探讨１．５ＴＭＲ颅脑液体衰减翻转恢复（ＦＬＡＩＲ）序列的合理扫描参数及其临床应用价值。材料和方法：首先对１８名健康志愿者行１．５ＴＭＲ的颅脑ＦＬＡＩＲ序列的参数选择试验，然后用筛选出的合理参数对２４例脑部疾病患者行ＦＬＡＩＲ序列与ＳＥ序列的对照扫描。结果：在１．５ＴＭＲ颅脑ＦＬＡＩＲ扫描中，当ＴＲ＝６０００ｍｓ时，ＴＩ为１７００－１８００ｍｓ接近脑脊液的无效值，ＴＥ以１６０ｍｓ为宜。ＦＬＡＩＲ序列与ＳＥ序列的对照扫描中，ＦＬＡＩＲ序列显示病变为７５／７６（９８．６８％），ＳＥ序列为６５／７６（８５．５３％），两者显示病变的敏感度有显著性差异（Ｐ＜０．０１）。结论：ＦＬＡＩＲ序列对靠近脑脊液的病变、脑组织水肿、室管膜下漏液、脑室和脑池内病变的检出较ＳＥ序列更敏感。     

磁共振快速液体衰减反转恢复序列对亚急性和慢性蛛网膜下腔出血的诊断价值

目的研究ＭＲ快速液体衰减反转恢复（ｆｌｕｉｄａｔｅｎｕａｔｅｄｉｎｖｅｒｓｉｏｎｒｅｃｏｖｅｒｙ,ＦＬＡＩＲ）序列诊断亚急性和慢性蛛网膜下腔出血（ｓｕｂａｒａｃｈｎｏｉｄｈｅｍｏｒｈａｇｅ,ＳＡＨ）的价值。方法３０例头部健康者和１７例次ＳＡＨ患者在发病后第４～３５天进行头部ＭＲＩ检查。扫描机为０．５Ｔ超导ＭＲ机。观察亚急性和慢性ＳＡＨ在ＦＬＡＩＲ的信号表现,并与同期ＣＴ和常规ＭＲＩ所见比较。再对４６个正常和病变的ＦＬＡＩＲ图像做双盲比较分析,以评价其诊断可靠性。结果ＦＬＡＩＲ成像显示亚急性和慢性ＳＡＨ（９４％）明显优于Ｔ１ＷＩ（４１％,Ｐ＜０．０１）和ＣＴ（２７％,Ｐ＜０．０１）。尤其在亚急性期,ＦＬＡＩＲ成像显示率达１００％,与ＣＴ（３３％,Ｐ＜０．０１）相比差异有非常显著性意义。双盲分析结果,无一例假阳性和假阴性诊断。结论快速ＦＬＡＩＲ序列诊断亚急性和慢性ＳＡＨ明显优于ＣＴ和常规ＭＲＩ,应作为本病检查的常规方法     

T1-Weighted MR imaging of the brain using a fast inversion recovery pulse sequence

The purpose of this paper was to develop and evaluate a fast inversion recovery (FIR) technique for T1-weighted MR imaging of contrast-enhancing brain pathology. The FIR technique was developed, capable of imaging 24 sections in approximately 7 minutes using two echoes per repetition and an alternating echo phase encoding assignment. Resulting images were compared with conventional T1-weighted spin echo (T1SE) images in 18 consecutive patients. Compared with corresponding T1SE images, FIR images were quantitatively comparable or superior for lesion-to-background contrast and contrast-to-noise ratio (CNR). Gray-to-white matter and cerebrospinal fluid (CSF)-to-white matter contrast and CNR were statistically superior in FIR images. Qualitatively, the FIR technique provided comparable lesion detection, improved lesion conspicuity, and superior image contrast compared with T1SE images. Although FIR images had greater amounts of image artifacts, there was not a statistically increased amount of interpretation-interfering image artifact. FIR provides T1-weighted images that are superior to T1SE images for a number of image quality criteria.     

MRI of the brain stem using fluid attenuated inversion recivery pulse sequences

Heavily T2-weighted fluid-attenuated inversion recovery (FLAIR) sequences with inversion times of 2000–2500 ms and echo times of 130–200 ms were used to image the brain stem of a normal adult and five patients. These sequences produce high signal from many white matter tracts and display high lesion contrast. The corticospinal and parietopontine tracts, lateral and medial lemnisci, superior and inferior cerebellar peduncles, medial longitudinal fasciculi, thalamo-olivary tracts and the cuneate and gracile fasciculi gave high signal and were directly visualised. The oculomotor and trigeminal nerves were demonstrated within the brain stem. Lesions not seen with conventional T2-weighted spin echo sequences were seen with high contrast in patients with infarction, multiple sclerosis, sarcoidosis, shunt obstruction and metastatic tumour. The anatomical detail and high lesion contrast given by the FLAIR pulse sequence appear likely to be of value in diagnosis of disease in the brain stem.     

Comparative evaluation of magnetization transfer contrast and fluid attenuated inversion recovery sequences in brain tuberculoma

AIM: To compare T1-weighted magnetization transfer (MT) with fluid attenuated inversion recovery (FLAIR) imaging for evaluating conspicuity and number of lesions in individuals with brain tuberculoma. MATERIALS AND METHODS: In all 28 patients with brain tuberculoma underwent MR examination using fast spin-echo (FSE) T2, spin-echo (SE) T1, T1-weighted MT and FLAIR imaging. Post-contrast T1-weighted MT imaging was taken as the gold standard for assessing the number of lesions. Tuberculomas detected both on T1-weighted MT and FLAIR imaging were examined for the wall to be defined, and were divided into two groups on the basis of presence (group 1) or absence (group 2) of perilesional oedema visible on FLAIR imaging. The mean signal intensity of the wall of the lesions and adjacent oedema or brain parenchyma was analyzed qualitatively and quantitatively. RESULTS: The number of lesions detected on T1-weighted MT was higher than on FLAIR imaging (209 versus 163). Conspicuity in both groups was better on T1-weighted MT images qualitatively as well as quantitatively. The difference in the signal intensity of the wall of the lesion and perilesional oedema was statistically significant only on T1-weighted MT images in group 1 (p=0.0003 versus 0.3), whereas in group 2 it was statistically significant both on T1-weighted MT and FLAIR imaging (p=0.009 versus 0.05). CONCLUSION: FLAIR imaging is not helpful in the examination of brain tuberculomas compared with T1-weighted MT imaging, as it neither contributes to the characterization of lesion nor assesses the true disease load.     

液体衰减反转恢复预脉冲序列在缺血性脑梗死表观扩散系数值定量研究中的价值

目的 探讨液体衰减反转恢复(FLAIR)序列预脉冲对缺血性脑梗死ADC值的影响及其临床应用价值.方法 回顾性分析139例次脑梗死的常规DWI和FLAIR-DWI资料,采用配对t检验的方法分别比较不同发病时间段的梗死病灶的常规ADC值(ADCCON)和FLAIR ADC值(ADCFLAIR).再根据梗死病灶是否累及大脑皮层将所有病灶分为皮层梗死组、皮层下梗死组,同样的方法比较皮层梗死组、皮层下梗死组以及对侧正常脑组织(对照组)ADCCON和ADCFLAIR值.结果 梗死病灶的平均ADCCON和ADCFLAIR值在发病0～6 h、7～12 h、13～24 h、2 d、3～4 d,5～7 d及8～14 d[ADCCON值分别为(0.55±0.07)、(0.50±0.09)、(0.50±0.13)、(0.50±0.13)、(0.62±0.14)、(0.60±0.12)、(0.72±0.20)×10-3mm2/s;ADCFLAIR值分别为(0.53±0.09)、(0.49±0.06)、(0.49±0.10)、(0.48±0.08)、(0.58±0.14)、(0.60±0.09)、(0.73±0.15)×10-3mm2/s]各个阶段差异均无统计学意义(P值均>0.05),发病15～30 d和31 d以上的病灶其ADCFLAIR值均低于ADCCON[15～30 d组ADCFLAIR和ADCCON分别为(0.95±0.21)、(1.02±0.27)×10-3mm2/s,31 d以上组分别为(1.10±0.30)、(1.36±0.41)×10-3 mm2/s],差异均有统计学意义(P值均<0.01);14 d以内的皮层梗死组和皮层下梗死组的ADCCON值[分别为(0.55±0.16)、(0.61±0.14)×10-3 mm2/s]与ADCFLAIR值[分别为(0.53±0.14)、(0.60±0.13)×10-3mm2/s]差异均无统计学意义(P值均>0.05);14 d以后ADCCON值则高于ADCFLAIR[皮层梗死组ADCCON和ADCFLAIR分别为(1.35±0.48)、(1.16±0.36)×10-3mm2/s,皮层下梗死组分别为(1.15±0.33)、(0.97±0.19)×10-3mm2/s],差异均有统计学意义(P值均<0.01);病灶对侧正常对照脑组织的ADCFLAIR值[(0.76±0.05)×10-3 mm2/s]低于ADCCON[(0.82±0.11)×10-3 mm2/s],差异具有统计学意义(P<0.01).结论 FLAIR预脉冲序列显著减低发病14 d后的脑梗死组织ADC值,这对于个体患者的脑梗死期龄的判断有帮助;同时FLAIR预脉冲能够通过减少自由水对正常脑组织ADC值的影响,从而增强相对ADC值检测细微缺血损伤的能力.     

Imaging of human brain activity at 0.15 T using fluid attenuated inversion recovery (FLAIR) pulse sequences

A 34% change in signal intensity correlated with visual stimulation was observed in the occipital lobes of three normal volunteers examined with MRI at 0.15 T using fluid attenuated inversion recovery pulse sequences. Similar results were observed at 1.0 T. A double difference technique in which difference images are themselves opposed provided an increase in sensitivity.     

低场磁共振T_1FLAIR序列在颅脑肿瘤诊断中的应用

目的 :通过T1FLAIR(液体反转恢复 )序列与传统SE(自旋回波 )序列T1加权图像对比分析 ,评价T1FLAIR作为T1成像序列对颅脑肿瘤的诊断价值。方法 :对 2 3例颅脑疾病患者均用两种序列检查。结果 :在 2 3例颅脑肿瘤中 ,T1FLAIR序列对病灶显示的图像清晰度比SE序列高。结论 :在相同病变检出率的情况下 ,T1FLAIR像在显示颅脑中灰白质对比度、病变和背景对比情况及病变的边界、大小、范围方面优于传统SE序列T1加权像 ,具有重要的临床诊断价值。     

MRI of the brain with ultra-short echo-time pulse sequences

As well as the long-T2 relaxation components normally detected with conventional imaging techniques, the brain has short-T2 components. We wished to use ultra-short (0.08 ms) echo time (UTE) pulse sequences to assess the feasibility of imaging these in normal subjects and patients. UTE sequences were employed, with or without fat suppression, 90 degree long-T2 suppression pulses, and selective nulling of long-T2 components using an inversion pulse. Subtraction of later echoes from the first was also used to reduce the signal from long-T2 components. We studied dive normal subjects and 15 patients with various diseases. Short-T2 components were demonstrated in grey and white matter. Increased signal from these components was seen in meningeal disease, probable calcification, presumed cavernomas, melanoma metastases and probable gliosis. Reduced signal was seen in some tumours, infarcts, mild multifocal vascular disease and vasogenic oedema. Further development and evaluation of these pulse sequences is warranted.     

脑胶质肉瘤的MRI表现

目的：评价MRI对脑胶质肉瘤的诊断价值。方法：经病理证实的脑胶质肉瘤6例，回顾分析其MRI表现。结果：病灶基本上表现为长T1、长T2信号，边界清楚，多数形态不规则，伴有囊变和坏死，可伴瘤内出血，生长具有侵袭性；少数为结节状。周围服组织水肿，占位效应明显。增强扫描：6例均明显强化，4例呈不规则环状强化，2例呈结节状强化；2例直接侵犯邻近脑叶，2例发现脑内转移灶。结论：脑胶质肉瘤通常发生于额、顶叶，MRI能够清楚地显示病变，但信号改变易与多形胶质母细胞瘤、恶性胶质瘤、转移瘤等相混淆。确诊仍依赖于组织病理学诊断。     

MRI对成人脑体积定量分析与临床对照研究

目的：探讨共振成像对成人脑体积定量分析的方法及其价值。方法：对20例正常对照组和20例实验组行垂直于海马长轴的倾斜冠状位磁共振T1及T2加权像扫描,测量海马、颞叶、额叶体积及颅腔容积,对其比值进行定量分析。结果：海马萎缩与临床痴呆密切相关。结论：采取垂直于海马长轴的倾斜冠状位磁共振T1及T2加权像扫描,测量海马体积与颅腔体积并计算其比值的方法,对判断与临床痴呆相关的脑萎缩敏感、可靠、切实可行。