液体衰减反转恢复(FLAIR)脉冲序列在颅脑MRI中的应用

作者报道了FLAIR序列在1例自愿者和4例脑部疾患病人中的应用。所有的检查用Picker HPQ 1.0T磁共振机。扫描参数为:TR6040～6710ms,TE130～240ms,TI1800～3000ms。层厚6～8mm,矩阵128或192×256。每一病例均采用单一数据收集。所有病例尚用传统的SE序列TE20和80,TR2500ms进行检查,并在一些病例中选择性的使用T_1加权扫描。作者见到,FLAIR脉冲序列可显示大脑半球相当多的解剖细节,特别是脑干中的细节显示得更加引人注目。皮质脊髓束、桥顶束、内侧丘系、小脑上脚内侧纵束以及三叉神     

肝脏液体衰减反转恢复序列最佳参数的选择及临床应用

目的:探讨液体衰减反转恢复(FLAIR)序列肝脏扫描的最佳参数及临床应用价值。方法:体外实验组将6组不同血红蛋白浓度液体和5组不同浓度的肝囊肿穿刺液埋于载体中,经0.5 T超导MR机行T2WI及FLAIR序列(TR6000 ms,TE 100 ms,TI 1500/1700/1900 ms)扫描,检测并分析相同病灶在T2WI及不同TI值的FLAIR成像的信号强度。结果:体外实验结果显示FLAIR成像随液体蛋白浓度(≥1.64 g/dl)升高和TI值延长其信号呈逐渐升高趋势,优选参数FLAIR成像(TI 1700 ms)可鉴别肝囊肿与肝血管瘤(P<0.05)。结论:FLAIR成像可初步判定液体蛋白含量,优选参数的FLAIR成像结合常规SE序列可提高肝脏病变的鉴别诊断。     

脉络膜裂囊肿的影像学诊断

本文分析CT、MR诊断的21例脉络膜裂囊肿,以提高对本病的认识。1材料与方法1.1一般资料MR诊断为脉络膜裂囊肿21例,男15例,女6例,年龄5~60岁,平均35.2岁。其中外伤5例,健康查体5例。1.2扫描方法采用日立MRP-7000AD 0.3T磁共振机,行自旋回波序列(SE)T1WI(TR/TE=500ms/20ms),快速自旋回波序列(FSE)T2WI(TR/TE=4000ms/117ms)及FLAIR序列(TR/TE/TI=6000ms/117ms/1500ms)分别采集轴位图像及冠状位SE-T1WI、矢状位FSE-T2WI图像,层厚5~8mm,间隔1~2mm。3例患者按照0.1mmol/kg静脉注射欧乃影后行轴位、冠状位及矢状位T1WI增强扫…     

呈一过性健忘的轻型颅脑损伤患者FLAIR法MRI所见

仅以一过性健忘为主诉的轻型颅脑损伤患者较少见,其影像诊断大多无异常,通常认为无器质性脑损害。作者采用FLAIR(液体衰减反转恢复序列)MRI对45例患者进行检查,使用0.5T没备,参数为TR 8000ms,TI 1 900ms,TE 120ms,T_2WI时TR4000ms,TE120ms。患者男28例,女17例,年龄6～74岁。同时以100例(8～82岁)无外伤但出现头痛、眩晕者为对照组进行比较。初诊时行头部CT扫     

3.0T磁共振乳腺成像扫描参数的优化

目的 探讨不同参数对乳腺MRI图像质量及扫描时间的影响.方法 (1)采用GE Signa Excite 3.0T MR成像系统和8通道乳腺线圈,对3个新鲜手术乳腺标本进行多序列、多参数扫描,根据图像质量及扫描时间选择适合乳腺MR成像的扫描序列和参数.(2)对10名健康志愿者采用FSE-IR、抑脂和非抑脂 FSE-XL T1WI和抑脂FSE-XL T2WI序列及不同参数进行乳腺MR成像,测量比较不同参数图像的信噪比.结果 其它参数相同时,采用以下序列和参数进行乳腺MR成像可在较短的扫描时间内获得较高的图像质量,包括FSE-IR序列:TR 6000 ms、TI 190 ms、TE 42 ms、带宽62.50 kHz、NEX 1、扫描层数18;FSE-XL T1WI序列:TR 500 ms、TE 11.5 ms、带宽50 kHz、NEX 2、扫描层数18;FSE-XL T2WI序列:TR 4200 ms、TE 80 ms、带宽41.67 kHz、NEX 1、扫描层数18.结论 3.0T MR乳腺成像,通过扫描参数的优化可节约扫描时间、提高图像质量.     

眼眶磁共振成像技术的研究

目的探讨眼眶磁共振扫描成像技术。方法采用GE1.5TsignaEchospeed或GE1.5TsignaTwinspeed,对30例患者做眼眶磁共振成像(MagneticResonanceImaging)。脉冲序列:SET1加权(weightedImagingWI),FSET2加权(weightedImagingWI),T2WI采用脂肪抑制技术或SET1flair,FRFSET2WIT2WI采用脂肪抑制技术。扫描方位:横轴位(Axial)、冠状位(Coronal)、矢状斜位(ObliqueSagittal)和横轴俯卧位(prone)等。扫描参数:Fov18cm×18cm,SET1WI:TR440msTE11ms,FSET2WI:TR3000msTE98ms或T1flair:TR2143ms,TE11ms,TI750ms,FRFSET2WI:TR3500msTE80ms,矩阵256×256,接收带宽15.63MHz,平均激励次数4次,层厚3～4mm,无间隔。增强对比剂用GdDTPA0.1mmolkg。结果横轴位可清晰显示视神经全长及眼内外直肌及与病变的关系。冠状位在同一层面可清晰显示视神经、眼内外直肌、眼上下直肌的断面及与病变的关系。矢状斜位可清晰显示视神经全长、眼上下直肌及与病变的关系。结论磁共振扫描参数的优化组合和选择正确的扫描方位,及T2WI脂肪抑制技术等的应用更有助于显示正常眼眶解剖结构及眼眶病变的定位和诊断。     

磁共振静脉造影诊断Cockett综合征的价值

目的 评价磁共振静脉造影(MRV)非增强髂静脉成像诊断Cockett综合征的价值.方法 采用Ingenia 3.0T超导型MRI系统,选择腹部表面线圈,扫描序列为M2DIPEAR (TR/TE=45/5.8 ms,翻转角60°)、THRIVE(TR/TE=6.8/3.5 ms,翻转角10°)、BTFE-SPAIR(TR/TE=3.4/1.7 ms,翻转角80°)和FLAIR(TR/TE=9 000/120 ms,翻转角90°),层厚均为3 mm,平均采集次数3次.结果 Cockett综合征MRV表现为受压骼静脉前后径变窄,横径增宽,血管前缘可见弧形压迹,侧支血管形成等;轻、中、重患者左侧髂静脉平均直径分别为7.52、4.83、2.76 mm,平均受压率分别为37％、69％、83％.结论 非增强MRV是可行的髂静脉狭窄诊断方法,尤其适用于特定人群检查需要.     

膝关节软骨MRI梯度回波序列的参数优化

目的：观察不同扫描参数对图像质量的影响，优化出不同的梯度回波序列的最佳扫描参数。方法：选择尸体膝关节2只，检查设备为Marconi eclipse 1．5T MR扫描仪。采用三维傅立叶稳态采集技术(3D FAST)；三维傅立叶稳态采集技术与脂肪抑制技术联合应用(FS 3D FAST)；三维射频毁损傅立叶稳态采集技术(3D FR-spoiled FAST，3D FR-spoiled FAST)；三维射频毁损傅立叶稳态采集技术与脂肪抑制序列联合应用(FS 3D FS-spoiled FAST)等4个序列进行扫描，每一序列采用不同的TE时间(5ms、10ms、15ms、20ms)结合不同翻转角(FLIP)(20、40、60)进行扫描(由于设备条件限制，3D FAST未进行，IE=5ms的扫描)。每一序列分别得到9组或12组不同成像参数的图像。分别计算不同序列、不同参数条件下的软骨与骨髓、软骨与液体的对比噪声比。数据采用SPSS软件包进行统计分析。结果：当，TE=10ms，FLIP=60时，FS 3D FAST序列及当，TE=5ms，FLIP=40时，FS 3D FR-spoiled FAST序列所得到软骨与骨髓及软骨与液体的对比噪声比均最佳。结论：①FS 3D RF-spoiled FAST序列的最佳扫描参数为，TE=5ms，FLIP=40；②FS 3D FAST序列的最佳扫描参数TE=10ms，FLIP=60。     

CT未见钙化和脂肪的肺错构瘤的MRI与病理对比分析

作者对5例CT扫描未发现钙化和脂肪者行MRI检查,并经手术确诊为肺错构瘤的患者进行分析。年龄52～70岁(平均59.4岁)男4例,女1例。1.5T MRI装置。用SE T_1 WI(TR=1心动周期,TE=12～20ms,矩阵132×256～192×256,2～4次激发),T_2 WI(TR=2～4心动周期,TE=90～128ms,矩阵128×256～138×256,2～4次激发)及3D FLASH(TR/TE=10/4ms,翻转角18°),另外使用3D FISP(TR/TE=5/2ms,翻转角15°)进行动态     

内侧副韧带损伤:多种征象的评价,伴骨挫伤的流行性和定位及其MR成像估价

作者对695例疑有内侧副韧带(MCL)损伤迹象的病人做了膝部MR检查,其中76例(男性45例、女31例,年龄18～60岁)MR上有MCL损伤征象,对其进行回顾性分析。25例无症状志愿者(男18例、女性7例、年龄20～46岁)作为对照组研究。采用Signal.5T磁共振装置,用胶端线圈。采用下列序列扫描:(a)矢状面中间加权,脂肪抑制SE成像(TR/TE=300/12ms,视野14cm,矩阵256×256,1次采集);(b)矢状面T_2加权,快速SE成像TR/TE=5000/100ms,视野14cm,矩阵256×256,2次采集,ETL=8,(c)冠状面中间加权SE成像TR/TE=1300/12ms,视野     

快速FLAIR技术在椎管内病变MRI中的应用及价值

目的介绍快速FLAIR技术在椎管内病变MRI中的应用并评价其价值。方法用0．5T超导型MR扫描仪在常规T     

3D MRI in multiple sclerosis: a study of three sequences at 3 T

The objective of this study was to assess the feasibility of using 3D acquisition at 3 T for imaging patients with multiple sclerosis (MS). Feasibility was assessed by three criteria based on acquisition time, specific absorption rate (SAR) and image quality. 47 patients with clinically definite MS underwent imaging in a Siemens 3T Trio MR scanner. Patient safety data were obtained following the scan sessions. The study had local ethics approval. The following three-dimensional (3D) sequences, all acquired coronally, were used: T2 fluid attenuated inversion recovery (FLAIR) (repetition time (TR) 6000 ms, echo time (TE) 353 ms, inversion time (TI) 2200 ms), 0.5x0.5x1 mm voxels, acquisition time 10 min 38 s; T2 turbo spin echo (TSE) (TR 3000 ms, TE 354 ms), 1x1x1 mm voxels, acquisition time 8 min 29 s; T1 inversion recovery (IR) (TR 2040 ms, TE 5.56 ms, TI 1100 ms), matrix 512x448 (0.5x0.5 mm pixels), 0.5x0.5x1 mm voxels, acquisition time 7 min 38 s. Total acquisition time was 26 min 45 s. Example images are presented. 3D scanning at 3 T provides highly detailed, high quality images with acquisition times tolerated by MS patients, even by those with severe disability. The volumetric data are suitable for a wide variety of post-processing techniques; the authors suggest that 3D studies at 3 T should be considered as the possible brain imaging protocol for either cross-sectional or longitudinal studies in MS and that the 3D T2 FLAIR sequence should be considered for the purposes of radiological diagnosis.     

颅脑MRI快速液体衰减反转回复技术探讨

目的：探讨快速液体衰减反转回复（ＦＬＡＩＲ）技术原理及其在颅脑的临床应用。材料与方法：对４０例健康志愿者及１２４例颅脑疾患患者前瞻性地进行快速ＦＬＡＩＲ及Ｔ２加权序列ＭＲ检查，并比较了快速ＦＬＡＩＲ上不同ＴＲ、ＴＩ（间隔时间）、ＴＥ组合所得图像质量。结果：ＴＲ／ＴＩ／ＴＥ为８０００／２０００／２００毫秒的组合能较好地抑制脑脊液信号。ＦＬＡＩＲ与快速自旋回波Ｔ２加权序列比较，能增加病灶的对比度，从而     

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。     

Magnetic resonance imaging of multiple sclerosis: a study of pulse-technique efficacy

Forty-two patients with the clinical diagnosis of multiple sclerosis were examined by proton magnetic resonance imaging (MRI) at 0.5 T. An extensive protocol was used to facilitate a comparison of the efficacy of different pulse techniques. Results were also compared in 39 cases with high-resolution x-ray computed tomography (CT). MRI revealed characteristic abnormalities in each case, whereas CT was positive in only 15 of 33 patients. Milder grades 1 and 2 disease were usually undetected by CT, and in all cases, the abnormalities noted on MRI were much more extensive than on CT. Cerebral abnormalities were best shown with the T2-weighted spin-echo sequence (TE/TR = 120/1000); brainstem lesions were best defined on the inversion-recovery sequence (TE/TI/TR = 30/400/1250). Increasing TE to 120 msec and TR to 2000 msec heightened the contrast between normal and abnormal white matter. However, the signal intensity of cerebrospinal fluid with this pulse technique obscured some abnormalities.     

Inversion recovery prepared turbo spin echo sequences with reduced SAR using smooth transitions between pseudo steady states.

This study investigates the contrast behavior of 2D inversion recovery (IR) prepared turbo spin echo (TSE) sequences that use RF pulse schemes with variable low flip angles (hyperTSE) to reduce RF power deposition. A framework of equations and calculations for adapting the sequence parameters is presented by which equivalent image contrast is achieved compared to conventional IR-TSE imaging. Although the inversion time (TI) and repetition time (TR) do not need to be changed, the echo time (TE) has to be prolonged such that the effective TE (TE(eff)) is preserved. Measurements in healthy volunteers confirmed this finding for IR-TSE sequences using different TIs: fluid attenuated inversion recovery (FLAIR), gray matter (GM)-white matter (WM)-IR, and short tau IR (STIR). The results demonstrate that hyperTSE sequences enable high-quality IR-prepared imaging with a considerably reduced specific absorption rate (SAR).     

Two-point T1 measurement: wide-coverage optimizations by stochastic simulations

Stochastic reliability of T1 measurement from image signal ratios is examined in the ideal case by stochastic simulations in the context of wide-coverage optimizations. Precise measurements prove to be accurate, and accurate ones precise. Sign-preserved inversion-recovery (IR)/non-IR techniques are the best ratio method, reciprocal non-IR/IR ones being equivalent, but inconvenient. Wide-coverage optima are relatively unsharp. Suggested guidelines for covering the 150- to 1500-ms T1 band are minimal relevant TE; TI about 400 ms; effective repetition times about in the ratio, TR2(IR)/TR1 (non-IR) = 2.5-3.0, and in a sum as long as possible up to about TR1 + TR2 = 3.5-4.0 s; signal-averaging after and only after TR1 + TR2 has been lengthened to the said region. Also suggested are different guidelines for covering T1 bands, 120-1200 and 200-1800 ms. Typically, precisions and accuracies improve linearly or faster with increasing S/N and (S/N)2, respectively. Unnecessarily high pixel resolutions or thin slicings exact great penalties in accuracies. Progressively shortening TR1 eventually transforms a wide coverage into a sharp targeting with small potential gains in a narrow T1 locality and large compromises almost everywhere else. The simulations yield an insight into applicabilities of standard error propagation analyses in two-point T1 measurement.     

不同TE对3.0T质子MRS谱线及代谢物定量的影响

目的:探讨不同回波时间(TE)对脑实质谱线信噪比(SNR)、基线稳定性及代谢物相对定量的影响.方法:36例受检者,使用GE Signa Excite HD 3.0T超导磁共振扫描仪,8通道头颈联合阵列线圈.每位受检者行2～7次不等的单体素PRESS序列1 H-MRS采集共得到132条谱线.检查参数为TR 1500 ms...