海绵窦影像检查方法比较研究

目的对正常CS的CT和MRI序列比较研究,探讨CS实用影像检查方法.方法60例鞍区及CS正常的病人分为三组①20例行SET1WI、FSET2WI、脂肪抑制SET1WI、GRET1WI和SET1WI增强扫描;②20例行3DSPGR和高分辨FSET2WI;③另20例行冠状CT增强扫描.采用双盲法评价并比较(秩和检验)8种检查方法对CS区正常解剖结构的显示能力和伪影程度.结果(1)显示CS内第Ⅲ、Ⅴ1和Ⅵ对颅神经SET1WI增强扫描和CT增强扫描优于其他6种序列(Ρ＜0.05);(2)显示CS边缘GRET1WI和3DSPGR不如其他6种方法(Ρ＜0.05);(3)显示CS间隙GRET1WI、3DSPGR和高分辨FSET2WI不如其他5种方法(Ρ＜0.05);(4)显示ICAGRET1WI、3DSPGR、高分辨FSET2WI和CT增强扫描不如其他4种方法(Ρ＜0.05);(5)显示骨结构CT优于MRI各序列(Ρ＜0.05);(6)磁敏感伪影GRET1WI、3DSPGR和高分辨FSET2WI多于其他序列(Ρ＜0.05);(7)ICA相位方向伪影GRET1WI和3DSPGR多于其他序列(Ρ＜0.05).结论CS区首选检查为冠状位SET1WI和FSET2WI;脂肪抑制SET1WI和SET1WI增强扫描可在必要时使用;疑有骨结构改变时,需使用CT或CT增强扫描;GRET1WI和3DSPGR不适于CS区检查.     

低场磁共振的化学位移及相关技术在骨关节病变中的应用初探

目的 :探讨低场磁共振的化学位移及相关技术在骨关节中的应用价值。方法 :2 1例骨关节病变均作常规SET1WI、FSET2 WI及GRET1WI、T2 WI扫描 ,并对图像作对比分析。结果 :GRET1WI、T2 WI均较SET1WI、FSET2 WI对病灶的检出、病灶与正常组织信号对比、病灶边缘和范围显示有明显的优势。结论 :低场磁共振的化学位移及相关技术简单 ,成像时间短 ,不受静磁场不均匀性的影响 ,在骨关节病变的诊断中具有较高的应用价值。     

低场强磁共振扫描诊断原发性输尿管癌(附11例报告)

目的:探讨低场磁共振扫描对原发性输尿管癌的诊断价值。方法:常规行肾区SE序列T1WI、T2WI横断面扫描及泌尿系磁共振水成像(MRU),再对病变区域行FSE T2WI薄层横轴位或冠状面扫描及脂肪抑制(STIR)序列扫描。结果:11例MRU均能显示输尿管不同程度梗阻征象,轴位扫描于梗阻部位显示异常软组织信号。结论:应用低场磁共振机行泌尿系水成像加梗阻区域T2WI薄层扫描及脂肪抑制序列扫描对原发性输尿管癌具有较高的术前诊断价值,尤其对IVU检查不显影或不适于行逆行肾盂造影者更显其独特的作用。     

小脑发育不良性节细胞瘤一例

患者女 ,33岁。头晕伴步态不稳 1年 ,恶心呕吐 1个月。MR扫描选用SE序列 ,T1WI :TR 5 0 0ms ,TE 2 0ms;T2 WI:TR 340 0ms ,TE 84ms。横轴面及冠状面扫描右小脑半球可见一 6 1cm× 5 9cm类圆形病变 ,T1WI呈低信号 ,T2 WI呈高信号 ,病变周界清晰 ,无水肿 ,病变内可见条纹状高低信号交替带。第 4脑室受压左移 ,幕上脑室扩张 (图1～ 3)。静脉注射碘普胺 15ml后 ,病变未见强化 (图 4 ,5 )。MRI诊断 :右小脑占位 ,考虑右小脑发育不良性节细胞瘤。手术所见 :右枕下旁正中切口 ,剥离肌层及骨膜 ,暴露术野 ,锯除小骨瓣 ,“ ”字形切开…     

眼眶MR成像IDEAL技术脂肪抑制效果和图像质量评价研究

目的:对比分析眼眶三点法非对称回波水脂分离成像(IDEAL)与短反转时间反转恢复序列(STIR)和化学饱和法的脂肪抑制效果和图像质量,探讨IDEAL在眼眶成像中的应用价值.方法:共260例患者进行眼眶MRI扫描,包括143例分别采用化学饱和法(41例)、STIR(52例)和IDEAL(50例)序列行冠状面T2 WI,以及50例和67例分别采用化学饱和法和IDEAL序列行增强后冠状面T1 WI扫描.对眼眶、鼻窦各解剖部位的图像质量和脂肪抑制效果进行主观评分,并且测量颞肌、内直肌和外直肌的信噪比,比较三种脂肪抑制技术的脂肪抑制效果和图像质量.结果:IDEAL组T2 WI对外直肌、内直肌、视神经和海绵窦的图像质量评分高于化学饱和法T2 WI(P＜0.05),对眼眶及邻近骨骼的脂肪抑制效果评分高于化学饱和法T2WI(P＜0.05),但对颞肌间隙脂肪抑制效果的评分低于化学饱和法T2WI(P=0.004).IDEAL T2WI对眼外肌、视神经、海绵窦的图像质量评分高于STIR序列(P＜0.05),对鼻甲、上颌窦内壁的图像质量评分低于STIR序列(P＜0.05);对眼眶、蝶骨大翼和颧骨的脂肪抑制效果评分高于STIR序列(P＜0.05),对颞肌间隙脂肪抑制效果评分低于STIR序列(P=0.000).IDEAL T2WI上颞肌的信噪比高于化学饱和法T2 WI(P=0.013),颞肌、内直肌和外直肌的信噪比高于STIR序列(P=0.000).增强后IDEAL T1WI对内直肌、下直肌、上颌窦内壁的图像质量评分高于化学饱和法T1WI(P＜0.05),对中鼻甲的图像质量评分低于化学饱和法(P＜0.05);对颞肌间隙和翼腭窝的脂肪抑制效果评分高于化学饱和法(P＜0.05),对肌锥外间隙脂肪抑制效果评分低于化学饱和法(P＜0.05).结论:IDEAL对眶内及眶周结构的显示效果优于化学饱和法和STIR序列,是目前眼眶MRI的最佳脂肪抑制技术.     

股骨头缺血坏死髋关节腔积液的MRI研究

目的　探讨股骨头缺血坏死 (AVN)的髋关节腔积液的MRI表现。资料与方法　对 86例 (12 1髋 )AVN的髋关节积液的MRI表现进行分析。全部病例均行SET1WI、FSET2 WI和T2 WI +压脂 ,横轴及冠状位扫描。参照Mitchell对关节腔液体定量方法 ,将液体分为 0～Ⅲ级进行统计。结果　关节腔积液于T2 WI和T2 WI +脂肪抑制冠状位扫描显示最清楚。 5 7%的AVN髋关节腔内可见Ⅱ～Ⅲ级的液体。股骨头皮质不完整组关节积液量与完整组差别有统计学意义 (P <0 .0 0 1)。结论　在AVN病例中 ,关节腔积液与病变进展相关 ,股骨头塌陷的髋关节腔内液体最多。MRI是显示髋关节腔液体的最敏感的无创方法。     

胰腺MRI:技术及诊断研究

目的 :探讨MR不同序列在胰腺病变诊断中的应用价值。方法 :84例胰腺检查包括 5 0例正常胰腺及 3 4例临床怀疑有病变的胰腺 ,其中包括 15例胰腺癌 ,2例胰岛细胞瘤 ,1例粘液性囊腺瘤 ,4例胰周肿瘤 ,12例胰腺炎。MR扫描序列包括常规SET1WI ;FSET2 WI ;增强前、后的脂肪抑制T1WI和GRE。结果 :3 4例异常胰腺中的 2 7例 ,增强前、后T1WI脂肪抑制像提供了最好的诊断信息 ,其次为增强后立即扫描的GRE像。未增强的GRE像极好地显示了急性胰腺炎的特征 ,SET2 WI像对胰岛细胞瘤及胰腺癌的肝转移显示较为敏感。结论 :增强前、后T1WI脂肪抑制序列及动态增强的GER序列 ,应为胰腺MRI的标准序列。     

MRI常规扫描序列与EPI序列对弥漫性轴索损伤诊断的对比研究

目的评价MRI常规FSET2WI、SET1WI序列与EPI序列对弥漫性轴索损伤的诊断价值.材料与方法42例弥漫性轴索损伤患者均进行MRI常规FSET2WI、SET1WI和EPI扫描.29例检查前静脉注射5～10毫克安定.结果FSET2WI、SET1WI序列运动伪影的发生率分别为83.3%、71.4%;EPI序列无一例出现运动伪影.EPI病灶与正常脑白质的对比度显著低于FSET2WI序列(p＜0.001),空间分辨率较FSET2WI、SET1WI序列差,信噪比最高.EPI共显示143个病灶,为FSET2WI显示病灶(174个)的82.2%,SET1WI序列显示133个病灶.对于直径大于1cm的病灶,EPI病灶显示数为FSET2WI序列的91.7%.FSET2WI、SET1WI序列所见的DAI主要并发症,EPI序列大都能显示.结论EPI的对比度与分辨率不如FSET2WI,对脑内小病灶、出血灶及脑底部病灶的显示还存在一定的限度,但EPI扫描时间极短,图像信噪比高、无运动伪影,能保证对脑内大多数病灶的显示,对弥漫性轴索损伤的诊断有重要的诊断价值,尤其对伴有烦噪的急性脑外伤患者或病情不允许进行长时间检查的患者,EPI可代替FSET2WI进行检查.     

剖宫产切口瘢痕早期妊娠1例

患者女,33岁。停经42天伴轻微腹痛就诊。查血β-HCG增高。既往剖宫产1次,剖宫产方式为子宫下段横切口;腹部超声提示宫颈妊娠。磁共振检查使用Siemens公司NOVUS 1.5T扫描仪,相控阵体线圈,平扫常规行横断位二维FLASH序列T1WI、TSE序列矢状位T2WI脂肪抑制成像及冠状位trufi序列,T1WI:TR 133ms,TE 2.85ms;T2WI:TR 3 500ms,TE 80ms;trufi:TR 4.8ms,TE 2.4ms。横断位     

0.5T磁共振梯度回波T2WI在脑出血病变中的应用价值

目的 探讨中场强磁共振仪梯度回波T2WI序列在脑出血病变诊断中的应用价值.方法 65例脑出血患者均行轴位梯度回波T2WI及常规磁共振T1WI、T2WI扫描以及FLAIR序列扫描.梯度回波T2WI扫描参数采用重复时间(TR)850 ms,回波时间(TE)为23 ms,层厚为6 mm,部分病例行双回波检查.结果 超急性期脑出血9例,梯度回波T2WI 上病变边缘及中心均可见低信号区,急性期脑出血20例,病变内均可见低信号区,亚急性期15例,病变中心低信号区较超急性期及急性期缩小,边缘低信号环变明显并扩大,慢性期及残腔期21例,病变软化灶周围呈更明显环状低信号.结论 中场强磁共振梯度回波T2WI序列对出血性病变中顺磁性物质显示有较强的特异性,可作为常规序列应用于出血性病变的检查.     

ESWAN序列参数对出血性剪切灶及脑静脉显示的影响和分析

目的研究多回波采集的增强T2*加权血管成像(ESWAN)序列的TR和TE参数对磁敏感效应的影响;调整更适合出血性剪切灶检出的ESWAN序列参数。资料与方法 10例弥漫性轴索损伤(DAI)患者经两种不同参数设置的ESWAN序列(两种序列的参数区别在于:短TE的ESWAN序列的首个回波TE 10 ms,TR 77 ms;长TE的ESWAN序列的首个回波TE 48 ms,TR 104 ms)扫描获得两组ESWAN图像,经后处理得到两组幅度图,将幅度图行最小强度投影(MinIP)后在两组图像上分别计数出血灶的数目、测量出血灶的容积,在三脑室上部及室间孔层面对显影的脑深部静脉计数。用配对t检验的方法检验两组数据的差异性。结果两组图像显示的微出血灶的数量及分布完全一致;长TE的ESWAN序列测量的微出血灶容积显著大于短TE的ESWAN序列;长TE的ESWAN序列显示的脑深部静脉数量明显多于短TE的ESWAN序列。结论 ESWAN序列的多回波采集优势,即使明显缩短首个回波的TE,后续的回波仍能保障对微出血灶检出的磁敏感效应;随着TE的延长,显影的静脉数量明显增多,但模糊效应也逐步放大,出血灶容积的放大比例也增加。对于脑外伤...     

Lesion discrimination in optic neuritis using high-resolution fat-suppressed fast spin-echo MRI

Fast spin-echo (FSE) is a new sequence with acquisition times currently down to one-sixteenth of those obtained with conventional spin-echo sequences, which allows high-resolution (512×512 matrix) images to be acquired in an acceptable time. We compared the higher resolution of FSE with the medium resolution of a short inversion-time inversion-recovery (STIR) sequence in depicting the optic nerves of healthy controls and patients with optic neuritis. Optic nerve MRI examinations were performed in 18 patients with optic neuritis and 10 normal controls. Two sequences were obtained coronally: fat-suppressed FSE (FSE TR 3250 ms/TEef 68 ms, echo-train length 16, 4 excitations, 24 cm rectangular field of view, 3 mm interleaved contiguous slices, in-plane resolution 0.5×0.5 mm) and STIR (TR 2000 ms/TE 50 ms/TI 175 ms, inplane resolution 0.8×0.8 mm, slice thickness 5 mm). FSE demonstrated much more anatomical detail than STIR, e. g. distinction of optic nerve and sheath. Lesions were seen in 20 of 21 symptomatic nerves using FSE and in 18 of 21 using STIR. Nerve swelling or partial cross-sectional lesions of the optic nerve were each seen only on FSE in 3 cases. Fatsuppressed FSE imaging of the optic nerve improves anatomical definition and increases lesion detection in optic neuritis.     

为什么部分肝脏局灶病变在超顺磁氧化铁增强T1WI上呈现高信号

目的:探讨肝脏病变在SPIO增强扫描T1WI上呈现高信号的机制.方法:肝脏局灶病变39例(56个病灶),其中33个恶性病灶(肝细胞癌10个、转移瘤21个、胆管细胞癌2个)和良性病灶23个(海绵状血管瘤9个,肝囊肿14个).平扫序列包括SE T1WI、FSPGR T1WI及FSE T2WI.SPIO(菲立磁)增强扫描序列包括FSE T2WI、SE T1WI(TE值分别为8 ms、20 ms)和 FSPGR T1WI(TE值分别为1.5 ms、4.2 ms).分析不同序列图像上病灶及肝实质的的信号变化.结果:在SPIO增强T1WI上,随着TE的延长,肝实质信号降低,肝内局灶病变信号相对增高.在SPIO增强长TE T1WI上,大部分恶性病灶及全部血管瘤呈相对高信号.结论:在SPIO增强T1WI上,SPIO对肝实质的T2*效应可能是部分局灶病变呈高信号的主要原因.     

Musculoskeletal MR imaging: turbo (fast) spin-echo versus conventional spin-echo and gradient-echo imaging at 0.5 tesla

The value of T2-weighted fast spin-echo imaging of the musculoskeletal system was assessed in 22 patients with various neoplastic, inflammatory, and traumatic disorders. Images were acquired with high echo number (i.e., echo train length) fast spin-echo (FSE; TR 2000 ms, effective TE 100 ms, echo number 13, lineark-space ordering), conventional spin-echo (SE; TR 2000 ms, TE 100 ms) and gradient-echo (GRE) sequences (TR 600 ms, TE 34 ms, flip angle 25°). Signal intensities, signal-to-noise ratios, contrast, contrast-to-noise ratios, lesion conspicuousness, detail perceptibility, and sensitivity towards image artifacts were compared. The high signal intensity of fat on FSE images resulted in a slightly inferior lesion-to-fat contrast on FSE images. However, on the basis of lesion conspicuity, FSE is able to replace time-consuming conventional T2-weighted SE imaging in musculoskeletal MRI. In contrast, GRE images frequently showed superior lesion conspicuity. One minor disadvantage of FSE in our study was the frequent deterioration of image quality by blurring, black band, and rippling artifacts. Some of these artifacts, however, can be prevented using short echo trains and/or short echo spacings.     

子宫腺肌症的MRI表现及诊断价值

目的探讨子宫腺肌症MRI特点及其诊断价值。方法回顾性分析经手术病理证实的31例子宫腺肌症的临床及MRI资料,应用自旋回波和快速自旋回波序列,常规行横断面FSE T2WI、SE T1WI及矢状面FSE T2WI扫描,其中10例病人加扫子宫解剖轴位及矢状位脂肪抑制FSE T2WI序列,分析其MR表现。结果弥漫性子宫腺肌症19例,以后壁结合带明显增厚为主的有11例。局限性子宫腺肌症12例,病变位于后壁7例,前壁4例,底部为主1例。28例T2WI呈与结合带信号相近的低信号影为主,内可见多发散在点状、小囊状高信号灶,21例T1WI呈与子宫肌层等信号,其中9例于T1WI也见点状、小囊状高信号。3例于肌层内见局限性类圆形结合带样信号。结论MRI可明确子宫腺肌症的范围及部位,脂肪抑制序列是非常有价值的检查方法。     

The MRI appearance of the optic nerve sheath following fenestration for benign intracranial hypertension

Optic nerve fenestration is carried out in cases of severe benign intracranial hypertension. This study aimed to monitor the optic nerve sheath appearances and orbital changes that occur following this procedure. The eight patients were all female with an average age of 37.3 years and a range of 20–58 years. The duration of symptoms was 2–6 years. Symptoms included headaches, diplopia and visual obscurations. Examination revealed severe papilledema. All investigations, including MRI, biochemical and immunological tests, were negative. Patients had fenestration of a 2 mm × 3 mm segment of the medial aspect of the optic nerve sheath. Imaging was obtained with a 1 T MRI machine using a head coil. Coronal, axial and sagittal 3 mm contiguous sections using STIR sequences with TR 4900 ms, IT 150 ms and TE 60 ms were obtained. Five patients showed clinical improvement. The post-operative MRI findings in four of these included a decreased volume of cerebrospinal fluid (CSF) around the optic nerve sheaths and a localized collection of fluid within the orbit. There were no MRI changes in the three patients with no clinical improvement. Decreased CSF volume around the optic nerve and a fluid collection within the orbit may indicate a favorable outcome in optic nerve fenestration. Received 23 June 1997; Revision received 16 January 1998; Accepted 18 March 1998     

动脉粥样硬化标本MRI扫描方法和序列优化

 目的 通过优化动脉粥样硬化标本的MRI扫描方法,以便标准化进行粥样硬化斑块的MRI研究.方法 取6例下肢动脉硬化闭塞症病人截肢后的股动脉.标本按两种方法处理,一种方法是直接裸标本(裸标本法),另一种是经过人工处理的标本(还原标本法).MRI用GE Signa Twinspeed 1.5T超导型磁共振仪,行常规轴位扫描,扫描序列包括SE T1WI,FSE T2WI,DOUBLE IR T1WI.观测指标:对比噪声比(CNR)和信噪比(SNR).并将数据进行t检验,双侧α＝0.05,P<0.05为有统计学意义.结果 裸标本和还原标本的对比噪声比(CNR)在T1WI、T2WI、DOUBLE IR T1WI各序列上比较均有明显统计学意义(P＝0.000).裸标本和还原标本的信噪比(SNR)在T1WI、T2WI、DOUBLE IR T1WI各序列上比较有明显统计学意义(P＝0.000).结论 还原标本的方法在对比噪声比(CNR)、信噪比(SNR)上明显优于裸标本方法.     

兔VX2恶性骨肿瘤浸润范围的DWI与病理对照研究

目的:探讨PROPELLER序列扩散加权成像(DWI)对显示恶性骨肿瘤浸润范围的价值.方法:建立30只兔右侧胫骨恶性骨肿瘤模型,并行MRI常规序列及DWI(b=500 s/mm2)检查.DWI图像上测量肿瘤实性区、肿瘤坏死区、肌肉水肿、正常肌肉、骨髓水肿的平均表观扩散系数(ADC)值;于矢状位肿瘤最大层面分别测量DWI...     

Fast spin-echo imaging of the knee: Factors influencing contrast

Conventional T2-weighted spin-echo magnetic resonance imaging of the knee requires a long TR. Fast spin-echo (FSE) imaging can improve acquisition efficiency severalfold by collecting multiple lines of k space for each TR. Compromises in resolution, section coverage, and contrast inevitably result. The authors examined the compromises encountered in FSE imaging of the knee and discuss the variations in image contrast and resolution due to choices of sequence parameters. For short TR/TE knee imaging, FSE does not appear to offer any advantages, since the increased collection efficiency for one section reduces the available number of sections, so that the total imaging time for a given number of sections remains constant relative to conventional spin-echo imaging. For T2-weighted images, considerable time can be saved and comparable quality images can be obtained. This saved time can be usefully spent on increasing both the resolution of the image and its signal-to-noise ratio, while still reducing total acquisition time by a factor of two. The preferred FSE T2-weighted images were acquired with a TR of 4,500 msec, TE of 120 msec, and eight echoes. The available number of sections is compromised, and the sequence remains sensitive to flow artifacts; however, the FSE sequence appears to be promising for knee imaging.     

Contrast media in MR arthrography of the glenohumeral joint: intra-articular gadopentetate vs saline: preliminary results

The purpose of this investigation was to compare gadopentetate and saline as contrast media in MR arthrograms of the glenohumeral joint. In 60 consecutive patients MR arthrograms with either gadopentetate (n = 26) or saline (n = 34) were performed. After injection of gadopentate, 3D gradient-echo (GE) images were obtained (TR 32 ms, TE 10 ms, flip angle 40 °). With saline, double-echo steady-state images (heavily T2-weighted 3D GE images) were obtained (TR 40 ms, TE 9/45 ms, flip angle 40 °). In the last 14 of these patients T2-weighted turbo spin-echo (SE) images were added (TR 2900 ms, TE 96 ms). Contrast-to-noise ratios standardized for imaging times proved to be superior for the gadolinium arthrograms compared with GE and SE saline arthrograms (intra-articular fluid vs subacromial fat: p = 0.0001 and 0.0008; intra-articular fluid vs supraspinatus tendon: p = 0.0001 and 0.046). Using a qualitative scoring system gadolinium arthrograms were superior to saline arthrograms (p < 0.0001 and p < 0.0001). Saline arthrograms in combination with GE and SE sequences are inferior to gadopentetate arthrograms with GE sequences. Received 24 May 1996; Accepted 30 August 1996