【作者】 马得廷；

【导师】 郭岩；

【作者基本信息】 泰山医学院 ， 影像医学与核医学， 2005， 硕士

【摘要】 目的：分析在低场脑部磁共振成像中液体衰减反转恢复(FLAIR)脉冲序列图像的正常表现,以此探讨FLAIR序列技术在脑部疾病中的临床应用价值。材料与方法：148例受检者(男性82例,女性66例,年龄2～84岁,平均47.6岁)均进行轴位FSE-T2WI、SE-T1WI和FLAIR序列检查。其中健康组40例,分析FLAIR序列图像的特点；病例组108例,脑梗塞44例、脑肿瘤30例、颅内出血18例、蛛网膜囊肿10例以及脑白质脱髓鞘6例,比较FLAIR序列图像与FSE-T2加权像对病灶数目、边缘清晰度、信号特点、内部结构特点等方面的显示情况。结果：(1)在正常FLAIR序列图像上,脑脊液呈明显的低信号,特定部位的脑白质和垂体柄常呈高信号,在轴位像上第三、四脑室内可见脑脊液的博动性高信号伪影。(2)病灶数目：108例病人中MRI共检出264个病灶,其中FLAIR图像显示病灶261个(98.86%),FSE-T2WI显示233个(88.26%),两者在显示病灶数目方面,FLAIR图像明显优于FSE-T2WI(p<0.01)；(3)病灶边缘清晰度：FLAIR图像显示病灶边缘清晰者243个(93.10%),FSE-T2WI显示病灶边缘清晰者180个(77.25%),两者在显示病灶清晰度方面,FLAIR图像明显优于FSE-T2WIp<0.01)。(4)病灶的信号特点：在FSE-T2WI上信号特点比较单一,只有2个病灶呈中等信号,其余呈高信号。在FLAIR图像上信号特点呈多样化,3个病灶呈中等信号,29个病灶呈低信号,16个病灶呈中间低信号伴周边高信号,其余病灶呈高信号。另外,FLAIR图像比FSE-T2WI更能清晰的显示病灶的内部结构。结论：在低场脑MRI中,FLAIR序列图像有其特殊的表现,不同于FSE-T2加权像,它能明显地抑制脑脊液的信号,提高病灶的检出率、清晰度和对比度,尤其是位于脑脊液区域的病灶；根据病灶的信号特点FLAIR像还有助于疾病的诊断和鉴别诊断。因此在低场脑MRI中,FLAIR序列应成为颅脑MRI检查的常规序列。更多还原

【Abstract】 Objective:To analyzed the normal appearance of fluid-attenuated inversion-recovery (FLAIR) pulse sequences images in low field MRI of the brain and evaluate the value of clinical application of FLAIR sequences in cerebral diseases.Materials and methods:The study included 148 subjects (82 men and 66 women; age range,2～84 years; mean age,47.6 years) who were studied using SE-T1WI, FSE-T2WI and FLAIR sequence at axial sections.40 of all subjects were healthy, which were analyzed the characteristic of FLAIR images; 108 of all subjects were patients with various cerebral diseases, including 44 patients with cerebral infarction,30 with intracranial tumor, 18 with intracranial hemorrhage,10 with arachnoid cyst, and 6 with cerebral white matter demyelination disease. The FLAIR images and FSE-T2 weighted images were compared for detectability, conspicuity, characteristic of signal intensity and intrinsic structure of lesions.Results:(1) On normal FLAIR images, the signal from CSF was suppressed greatly, and high signal intensity were frequently seen in regions of the particular cerebral white matters and pituitary stalk. Ventricular CSF pulsation artifact (VCSFA) is commonly found in the third and fourth ventricles on axial FLAIR images. (2) Lesion detection:264 lesions were identified with MRI in the 108 patients. FLAIR images detected 261 (98.86%), and FSE-T2 weighted images,233 (88.26%) of the 264 lesions. The difference in lesion detection between them approached statistical significance (p<0.01). (3) Lesion conspicuity:243 (93.10%) lesions were clear with FLAIR images in demonstrating the border of lesions, and 180 (77.25%) ones with FSE-T2 weighted images. The difference in lesion conspicuity between them is statistically significant (p<0.01). (4) Signal intensity: On FSE-T2 weighted images, the signal intensity of lesions was single, only two of them were middle signal intensity, the rest were hyperintense. However, on FLAIR images, the signal intensity of lesions was multiple,3 lesions were middle signal intensity,29 ones were hypointense,16 ones were hypointense centrally with a thin peripheral rim of hyperintensity, the rest were hyperintense. Moreover, FLAIR images showed the intrinsic structure of lesions more clearly than FSE-T2 weighted images.Conclusion:In low field MRI of the brain, there were special appearances on FLAIR images which were different from FSE-T2 weighted images. The FLAIR sequence can reduce greatly the signal from CSF, which produced high lesion contrast in areas close to CSF. Lesions were demonstrated with greater conspicuity on FLAIR images than FSE-T2 weighted sequences in patients with cerebral diseases. Moreover, it is more helpful to diagnose and distinguish from intracranial diseases with the characteristic of lesion’s signal on FLAIR images than FSE-T2 weighted images. Therefore, FLAIR sequence can be used as a conventional sequence of the examination in low field MRI of the brain.更多还原