磁共振3D神经成像对腰骶丛显示的对比研究

目的探讨1.5T磁共振三维快速自旋回波成像(3D sampling perfection with application optimized contrasts by using different flip angle evolutions,3D-SPACE)与多回波融合成像(multiple echo data image combination,3D-MEDIC)序列对正常人腰骶丛神经的显示。方法 31例无症状正常志愿者行MRI检查,包括常规腰椎MRI、3D-SPACE及MEDIC序列扫描,原始图像传入后处理工作站行多平面图像重组。结合原始及重组图像,比较3D-SPACE及MEDIC序列图像腰骶丛神经根的信噪比及对神经的显示评分。结果 3D-MEDIC序列显示神经根的信噪比高于3D-SPACE序列(分别为70.15±24.03及28.78±7.12,P=0.000)。3D-MEDIC序列对腰骶丛的显示评分高于3D-SPACE序列(P=0.000)。结论1.5T磁共振腰骶丛神经显像中,3D-MEDIC序列优于3D-SPACE序列,可清晰显示神经根走行,是常规腰椎MRI的重要补充。     

3D-STIR序列增强扫描在腰骶丛神经成像中的应用研究

目的探讨3.0T磁共振三维短恢复时间反转恢复(3D-STIR)序列增强扫描在腰骶丛神经成像中的可行性及其实际应用的效果和价值。资料与方法对20名健康自愿者及21例腰骶丛神经病变患者行常规扫描序列、3D-STIR序列平扫及3D-STIR序列增强扫描,观察所得图像,评价显示情况和对比噪声比。结果 3D-STIR序列及其增强扫描可清楚、明确地显示所有自愿者腰骶丛神经的构成、走行、连续性、形态、信号;3D-STIR序列增强扫描能明显改善背景抑制效果,可清楚显示肿瘤、外伤及椎间盘突出累及腰骶丛神经所致各种征象。结论 3D-STIR序列增强扫描可以更清楚地显示腰骶丛神经解剖结构,并且能获得更好的背景抑制效果,在腰骶丛神经损伤的定位定性诊断和损伤程度判定方面有广阔的应用前景。     

扩散加权神经成像在腰骶丛神经影像诊断的临床应用

目的 探讨扩散加权磁共振神经成像(DW-MRN)和选择性水激励脂肪抑制技术(PROSET)腰骶丛神经成像特点及其临床应用价值.资料与方法 对25例腰骶部受检者行常规MRI、PROSET及DW-MRN.结果 PROSET对腰骶丛神经显示率达100%,对腰丛神经显示效果好于DW-MRN,差异有统计学意义(χ~2=6.300,P<0.05),对腰骶干和骶神经的显示效果亦好于DW-MRN,但差异无明显统计学意义(χ~2=5.922,P>0.05;χ~2=3.870,P>0.05).PROSET能清晰显示腰骶神经根和根鞘,对神经根病变显示良好.DW-MRN对腰骶从神经受累增粗和信号增高较敏感,最大密度投影(MIP)重组的3D图像可清晰显示腰骶丛节后神经.结论 DW-MRN可立体、直观地显示腰骶丛神经节及节后神经.PROSET与DW-MRN结合,能使腰骶丛神经病变在精确成像下直观诊断.     

iMSDE MR神经成像在腰骶丛神经及其病变中的应用

目的探讨iMSDE MR神经成像(iMSDE-MRN)在腰骶丛神经的成像特点及其临床应用价值,并与MR扩散加权背景抑制神经成像(DWIBS-MRN)对比分析。方法收集20例健康志愿者及30例腰骶丛神经病变的病例,分别行常规MR检查、iMSDE-MRN及DWIBS-MRN神经成像序列检查,对L_5及S_1、S_2、S_3、S_4的显示情况进行评分对比,观察分析30例腰骶丛神经病变两种神经序列上神经和病变的显示情况,显示结果与手术病理对照。结果 iMSDE-MRN和DWIBS-MRN对L_5、S_1、S_2、S_3的显示率达100%;iMSDE-MRN对S_4的显示效果明显尤于DWIBS-MRN,其差异有统计学意义(P0.05)。对30例腰骶丛神经病变iMSDE-MRN均能清晰地显示腰骶丛神经的结构、走行及信号特征,特别是可以显示细小的神经结构,能够清楚显示病变对神经的包绕、推压等特征。iMSDE-MRN较DWIBS-MRN能更清楚的显示相关神经的细微结构及病变的信号特点。结论 iMSDE-MRN可以清楚显示腰骶丛神经及病变的信号特点,特别是对细小的神经结构的显示优于DWIBS-MRN,为腰骶丛神经及其病变的显示提供了一种新的可行性方法。     

腰骶部神经根和神经节MR成像技术探讨

目的探讨比较3D-SPGR T1、3DFIESTA、STIR脉冲序列冠状位显示腰骶神经的优劣。方法搜集30例腰腿痛患者,对其腰椎行MRI检查,在常规行T1和T2矢状位及椎间盘平面T2横断位扫描序列的基础上加扫3D-SPGRT1、3DFIESTA、STIR序列冠状位扫描,将扫描所得图像传入GE ADW4.2工作站进行后处理,图像可任意层厚重建,得到多角度、多平面的脊髓神经图像并观察其解剖形态,对所得图像评分进行统计学分析。若P﹤0.05,则视为有明显差异。结果 3DSPGR优于STIR和3DFIESTA序列,其差异有统计学意义(P<0.05);STIR序列优于3DFIESTA序列,但其差异无明显统计学意义(P>0.05)。结论对于腰骶丛神经的成像3D-F SPGR序列较3DFIESTA、STIR序列具有更高的图像信噪比、更好的组织对比、能更好地显示腰骶丛神经的全貌。     

MR选择性激励技术(PROSET)在诊断脊神经根病变中的应用

目的：探讨选择性激励技术（PROSET）在诊断腰骶部脊神经根病变中的临床应用价值。方法：将正常志愿者15例作为对照组,脊神经根病变47例作为观察组,进行常规扫描和PROSET冠状面腰骶部神经根成像,所有图像均经3D最大信号强度投影（MIP）后处理,观察脊神经根形态、走行及与病变的关系。结果：对照组PROSET成像均能清楚显示硬膜囊、硬脊膜鞘外形及脊神经根、神经节和部分节后段的走行,MIP重建图像能多方位观察神经根走行。观察组PROSET成像可以清楚显示病变对神经根压迫和侵犯程度。结论：PROSET序列对显示腰骶神经根解剖具有独特优势,结合常规磁共振图像,为临床诊治腰骶神经根病变提供较好的依据。     

T2-tirm与3D-medic MRI序列在显示脊神经损伤中的效能比较

目的比较T2-tirm序列和3D-medic序列显示脊神经解剖形态及病变的能力。方法 20例患者均经T2-tirm及3D-medic两种序列的脊神经成像,将获得的图像进行最大强度投影(MIP),多平面重组(MPR)及曲面重建(CPR)以充分显示脊神经损伤。以脊神经节后神经部分同层显示情况比较两种序列对脊神经解剖结构及病变的显示能力。结果 T2-tirm和3D-medic两种序列都能显示脊神经影像,但显示程度不同,3D-medic序列在显示脊神经解剖结构细节及病变方面优于T2-tirm序列。结论 3D-medic MRI神经成像术操作简单,能直观清晰地显示脊神经的走行,并提供较为可靠的脊神经局部解剖信息,值得在临床上推广使用。     

1.5T MR三维双回波稳态水激发序列显示腰骶神经的初步研究

目的 探讨磁共振三维双回波稳态水激发序列(3D-DESSWE)在正常腰骶神经成像中的价值.方法 采用1.5T MR 3D-DESSWE序列对22例健康志愿者进行腰骶神经扫描,对源图像进行最大强度投影(MIP)及多平面重建(MPR),获得后处理图像后与格氏解剖学图谱对照.由2名阅片者协商采用3分法(0~2)对3D-DESSWE序列显示腰骶神经的可靠性进行评估,对两侧腰骶神经主干的长度及脊神经节的长、宽进行测量.结果 所有志愿者两侧腰骶神经主干均获得清晰显示(1~2分).在3D-DESSWE图像中,腰骶神经呈高信号,周围软组织及骨质结构呈相对低信号.两侧的腰骶神经长度、脊神经节大小及显示评分无显著差别(P>0.05).结论 3D-DESSWE序列可以清晰显示腰骶神经的解剖结构,为描述腰骶神经提供了一种新方法.     

正常腰骶部脊神经根的解剖及MR PROSET成像表现

目的观察和探讨正常腰骶部脊神经根的解剖和磁共振PROSET序列显示腰骶部神经根的价值。方法采用PROSET技术做冠状面正常腰骶部神经根成像20例,所有原始图像均经3D最大信号强度投影(MIP)后处理。结果20例PROSET成像均清楚显示硬膜囊、硬脊膜鞘外形及脊神经根、神经节和部分节后段的走形,MIP重建图像能多方位观察神经根走形。结论PRO-SET序列对显示腰骶神经根解剖具有独特优势,结合常规磁共振图像,为临床诊治腰骶神经根病变提供满意的影像学依据。     

3D SPACE STIR结合DTI显示腰骶神经根病变的研究

目的探讨结合DTI的短回波反转恢复各向同性变换角度RF激发3DT2TSE序列(SPACE:Sampling Perfection with Application optimized Contrasts using different flip angle evolutions)在腰骶丛病变成像中的应用价值。方法10例健康志愿者和32例腰骶丛神经病变患者行常规扫描序列、3DSPACE STIR序列和DTI序列扫描。结果 10名健康自愿者,L1~S1腰骶神经根3DSPCACE STIR序列均得到清晰显示。32例腰骶丛神经病变中,神经根受推压移位27例,受侵犯5例。椎间盘突出所致神经根受损的FA值降低(P0.05),而ADC值升高(P0.05)。结论 3DSPACE STIR序列具有较好的组织对比,图像可被作为测量DTI数据的FA值及ADC值的高分辨率蒙片,两者结合可以很好评估腰骶神经丛的神经压迫位置和神经受侵犯的范围和程度。     

磁共振弥散加权成像对急性皮层下脑梗塞的评价

目的 研究磁共振弥散加权成像（DWI）诊断急性皮层下脑梗塞的准确性以及对急性与非急性皮层下脑梗塞的鉴别诊断。材料与方法 对32例临床诊断为急性皮层下脑梗塞的患者和20例对照者在不同时间内进行常规MRI检查和弥散加权MRI检查,并用盲法进行对照观察。对所有病例的病变部位均按神经解剖进行准确定位并与患者的症状、体征相联系。结果 DWI诊断急性皮层下脑梗塞的敏感性、特异性及准确性分别为97％、95％和96％。32例中有3例常规MRI检查未发现急性梗塞性。另20例常规MRI检查均显示为多发梗塞,而DWI只显示单个急性病灶,且患者的症状、体征与DWI上显示的病灶相符。结论 DWI对诊断急性皮层下脑梗塞有很高的准确性,能发现常规T2WI不能发现的早期脑梗塞,并能鉴别急性与非急性梗塞。     

High-resolution diffusion-weighted MR imaging of the human lumbosacral plexus and its branches based on a steady-state free precession imaging technique at 3T

3D diffusion-weighted steady-state free precession imaging (3D DW-SSFP) with isotropic resolution was performed to delineate structures of the human lumbosacral plexus (LSP). 3D DW-SSFP clearly revealed detailed anatomy of the LSP and its branches. Our data suggest that the sequence based on 3D DW-SSFP can be used for high-resolution MR imaging of the peripheral nervous system.     

Magnetic resonance imaging of the prostate

Twenty-two normal volunteers and 32 patients with either benign prostatic hypertrophy or prostatic carcinoma were examined by magnetic resonance imaging (MRI). The images were of high quality and clearly demonstrated the prostate gland and the surrounding anatomy but were of limited value in differentiating between benign and malignant prostatic disease. Using a specific pulse sequence, the authors were able to visualize what they believed to be the periprostatic venous plexus and suggest that the demonstration of this venous plexus may be of value in showing extraglandular spread of carcinoma of the prostate.     

颌面外科及正畸中三维CT的临床应用

目的：探讨三维CT在颌面外科和正畸中的应用价值。资料与方法：颌面部骨折55例，颌面部肿瘤14例，颌骨及牙发育畸形14例。所有病例均经螺旋CT扫描后进行骨的表面重建，肿瘤患者还行肿瘤区的多平面重建，颌骨畸形牙咬合错位者利用牙科软件行牙体的表面重建和牙根的多面重建。重建图像分别与原始轴位图、手术所见对照，并与正畸模型进行对照。结果：（1）55例颌面骨部折和14例颌面部肿瘤三维重建图像显示的骨折、肿瘤部位与原始轴位图显示一致，与手术所见相符，而且立体感更强。（2）14例颌骨及牙发育畸形三维重建图像清楚显示颌骨畸形、牙咬合错位牙根方向的情况。根据三维图像制订、实施手术方案和短形正畸计划，获得良好的效果。结论：三维CT可准确地显示颌骨的病变，可多方位、多角度观察病变，立体感强，有助于颌面外科疾病的治疗、手术计划的制订和实施，牙科软件行牙的表面重建及牙根的多平面重建，能清楚地显示各个牙根的走向，为牙的矫形、种植术前计划起重要的指导作用。     

Diffusion weighted imaging in breast MRI: comparison of two different pulse sequences

RATIONALE AND OBJECTIVES: Comparison of two different diffusion weighted (DW) sequences in breast MRI regarding the differentiation between benign and malignant lesions. MATERIALS AND METHODS: Breast MRI including two different DW sequences was performed in 165 consecutive women. Inclusion criteria for DW imaging and ADC evaluation were histologically proven focal mass lesions with a diameter of more than 5 mm in dynamic contrast-enhanced MRI. The DW sequences were pre-contrast echo-planar imaging with spectral fat saturation (EPI fs) and DW EPI with inversion recovery (EPI STIR) (b-values: 50, 400, and 800). Lesions were analyzed regarding visibility in DW sequences and ADC values. RESULTS: Inclusion criteria were fulfilled in 56 women with 69 lesions. Five lesions could not be evaluated for different reasons. Finally, DW sequences were evaluated in 51 women with 64 focal mass lesions (15 benign, 49 malignant). The visibility of the lesions was significantly better in the EPI fs sequence (P<0.05). The ADC values (10(-3) mm(2)/s) in the EPI fs were 1.76, 2.58, and 1.21 (mean, maximum, minimum, respectively) for benign lesions and 0.90, 1.19, and 0.34 for malignant lesions. Respective values in the EPI STIR sequence were 1.92, 3.20, 1.10, and 0.91, 1.43, 0.35. Only in the EPI fs sequence there was no overlap in ADC values between benign and malignant lesions. CONCLUSION: The DW MRI of the breast with EPI fs and EPI STIR sequences has a high potential to differentiate between benign and malignant breast lesions. Due to better lesion visibility and selectivity, the EPI fs sequence should be preferred.     

Readout-Segmented Echo-Planar Imaging in Diffusion-Weighted MR Imaging in Breast Cancer: Comparison with Single-Shot Echo-Planar Imaging in Image Quality

Objective

The purpose of this study was to compare the image quality of standard single-shot echo-planar imaging (ss-EPI) and that of readout-segmented EPI (rs-EPI) in patients with breast cancer.

Materials and Methods

Seventy-one patients with 74 breast cancers underwent both ss-EPI and rs-EPI. For qualitative comparison of image quality, three readers independently assessed the two sets of diffusion-weighted (DW) images. To evaluate geometric distortion, a comparison was made between lesion lengths derived from contrast enhanced MR (CE-MR) images and those obtained from the corresponding DW images. For assessment of image parameters, signal-to-noise ratio (SNR), lesion contrast, and contrast-to-noise ratio (CNR) were calculated.

Results

The rs-EPI was superior to ss-EPI in most criteria regarding the qualitative image quality. Anatomical structure distinction, delineation of the lesion, ghosting artifact, and overall image quality were significantly better in rs-EPI. Regarding the geometric distortion, lesion length on ss-EPI was significantly different from that of CE-MR, whereas there were no significant differences between CE-MR and rs-EPI. The rs-EPI was superior to ss-EPI in SNR and CNR.

Conclusion

Readout-segmented EPI is superior to ss-EPI in the aspect of image quality in DW MR imaging of the breast.     

The lumbosacral plexus: anatomic-radiologic-pathologic correlation using CT

Before high resolution computed tomography (CT), the lumbosacral plexus was nearly impossible to image. While individual elements of the plexus are not consistently resolved using CT, the regional anatomy is reproducible and allows accurate evaluation. Normal regional anatomy was established by axial cadaver dissection and review of 233 normal computed tomographic examinations. This regional anatomy has been presented in detail. In addition, 17 patients with lumbosacral plexopathy due to benign, neoplastic and idiopathic causes were imaged. Our results show that CT is effective in the evaluation of suspected structural lesions of the lumbosacral plexus.     

胎儿磁共振成像序列的对比研究及应用

目的:比较单次激发快速自旋回波序列(SSFSE)和快速成像稳态采集序列(FIESTA)对胎儿解剖结构和病变的显示能力,探讨两种快速成像序列在胎儿MRI中的临床应用价值。方法:82例中晚期妊娠孕妇行单次激发快速自旋回波序列和快速成像稳态采集序列扫描,并根据图像平均信号强度、图像质量和图像伪影等方面对两个序列在胎儿解剖结构和病变的显示能力方面做出统计学分析。结果:两种序列对胎儿解剖结构和异常病变的显示各有优点和不足,SSFSE和FIESTA均能清楚显示胎儿正常脏器的解剖结构和异常病变。SSFSE的平均信号强度和分辨力要高于FIESTA序列,但其呼吸伪影要比FIESTA序列明显,而对于液体的显示FIESTA要优于SSFSE。结论:SSFSE序列和FIESTA序列对胎儿的不同组织其显示能力不同,所以根据病情做出不同的选择是非常重要的。