平衡快速梯度回波序列的临床应用价值

目的评价平衡快速梯度回波序列(balance-FFE，B—FFE)的临床应用价值。方法860例怀疑胸腹疾患的患者分别行快速自旋回波(TSE)和B—FFE检查，然后对TSE T2WI序列与B—FFE序列的图像清晰度、血管显示、脏器边界及间隙解剖及病灶检出进行分析比较。结果B—FFE序列的图像清晰度、血管显示及解剖显示均优于TSE T2WI序列，对肝癌和转移瘤的检出率略低于TSE，肝血管瘤与肝囊肿的检出率略高于TSE.结论B—FFE能很好地显示血管系统及其病变侵犯；清楚地显示胆管内外的病变，重建后的图像质量可与MRCP相媲美；扫描速度快，几乎无运动伪影，对较重或不能屏气的患者有明显的优势。     

磁共振成像在诊断幼年特发性关节炎中的应用

目的:探讨幼年特发性关节炎(JIA)患者膝关节磁共振成像(MRI)的主要表现及检查技术要点。方法:探讨T1加权自旋回波序列(T1W/SE)、T2加权快速自旋回波序列(T2W/TSE)、增强后T1W脂肪抑制三维快速梯度回波序列(SPIR/3D/FFE)等技术及其在膝关节MRI中的作用,并分析42例JIA患儿的膝关节MRI表现。结果:增强后T1脂肪抑制三维快速梯度回波序列结合T1W、T2W序列能综合评价JIA造成的关节病变程度,其主要表现包括滑膜增生、血管翳形成、关节腔渗出积液、骨髓水肿、半月板变性、关节软骨破坏、腘窝淋巴结肿大等。结论:增强后T1脂肪抑制三维快速梯度回波序列结合传统T1W、T2W成像对判断JIA膝关节病变有重要价值。     

不同MRI序列显示乳腺病变的比较

目的比较不同MRI序列显示乳腺病变的价值.方法对79例乳腺癌和68例乳腺良性疾病患者采用自旋回波(SE)序列、快速自旋回波(TSE)序列、脂肪抑制(FS)成像、快速小角度激发(FLASH)序列、静态或动态增强扫描,比较不同MRI序列对乳腺病变的显示检出情况.结果脂肪抑制成像序列对乳腺病变的检出率高于SE序列,SE序列有利于病灶病理解剖关系的显示,MR增强扫描可检出所有乳腺病灶且有助于明确病灶的内部结构、浸润范围及其血供情况.结论 SE、TSE应为乳腺MR检查的常规序列,脂肪抑制成像序列必不可少,MR增强扫描对病灶的定性诊断很有价值,尤其是FLASH动态增强扫描.     

MRH在内耳成像及病变诊断中的应用研究

目的 比较多平面重建(MPR)、最大密度投影(MIP)、容积再现(VR)三种磁共振水成像技术(MRH)后处理方法 对内耳解剖结构的显示情况及对内耳病变的应用价值.方法 选择40例健康成人及35例临床确诊为感音神经性耳聋(SNHL)的患者内耳行高分辨三维快速自旋回波T2加权序列(3D TSE T2WI)横断面扫描,然后行...     

快速液体衰减反转恢复序列技术在脑部疾病中的诊断价值

目的:探讨快速液体衰减反转恢复(fast fluid attenuated inversion recovery,Fast FLAIR)序列技术在脑部疾病中的诊断价值.方法:对76例脑部疾病患者进行Fast FLAIR序列及常规快速自旋回波(fastspin-ccho sequence,FSE)序列T2加权成像扫描,比较两种序列对病灶的显示情况.结果:在76例脑部疾病中,Fast FLAIR序列共显示病灶172个,而FSE序列T2加权成像显示123个.前者显示的病灶较后者清楚,在FastFLAIR序列上病灶与正常脑组织的对比度更高.结论:Fast FLAIR序列对颅脑病变的显示优于FSE序列T2加权成像,特别是对脑表面或脑室周围病灶的显示,Fast FLAIR有很高的临床使用价值.     

关节软骨MR成像方法的临床研究

目的 评价关节软骨检查的各种MRI扫描序列。方法 对正常健康志愿者30例进行膝关节MRI扫描，MRI序列包括质子和T2加权快速自旋回波序列(FSE-PD／T2)，附加脂肪抑制的质子和T2加权快速自旋回波序列(FS-FSE-PD／T2)和脂肪抑制的三维快速扰相梯度回波序列(FS-3D-SPGR)。结果 与常规膝关节检查的FSE-PD／T2序列比较，FS-3D-SPGR的软骨信噪比(SNR)和其对软骨下骨，关节液等关节软骨周围组织的对比噪声比(CNR)更高。结论 FS—FSE—PD／T2可作为膝关节检查的常规序列。FS-3D-SPGR序列可作为关节软骨检查的最佳扫描序列。     

梯度回波序列(GRE)在脊椎病变的诊断作用

目的：探讨GRE序列诊断脊椎病变的作用。方法：回顾使用常规SE序列加GRE序列扫描，经病理临床证实的42例脊椎MRI图像资料，对比分析快速自旋回流（FSE）T2加权与GRE的MRI表现、评估GRE在脊椎病诊断中的作用。结果：GRE序列有椎肿瘤、挫伤显示敏感度高于FSE－T2WI，并有利于结核及肿瘤等病变的鉴别。结论：SE序列配合应用GRE技术可明显提脊椎病变检出率。     

臂丛神经磁共振成像技术初步研究

目的：探讨臂丛神经磁共振成像的技术方法及其可行性。方法：对15例正常志愿者行双侧臂丛神经成像：包括常规快速自旋回波序列T1加权（T1W/TSE）、快速自旋回波序列T2加权（T2W/TSE）、快速自旋回波序列T2加权加SPIR脂肪抑制（T2W/SPIR）冠状位扫描以及弥散加权背景抑制成像序列（DWIBS）轴位扫描。结果：T1W/TSE、T2W/TSE、及T2W/SPIR对臂丛节后神经同层显示率分别为53.3%、56.7%和83.3%;DWIBSMIP重建图像对臂丛神经的全貌显示较为完整、清晰、直观;T1W/TSE、T2W/TSE、T2W/SPIR及DWIBSMIP重建图像的对比噪声比分别为10.9±0.9、10.7±1.3、18.5±6.8和29.9±13.3,T2W/SPIR序列和DWIBSMIP重建图像的对比噪声比明显高于T1W/TSE和T2W/TSE序列。结论：T2W/SPIR序列对臂丛神经的同层显示率及图像的对比噪声比明显高于常规T1W/TSE、T2W/TSE序列,DWIBSMIP重建图像能够显示臂丛神经的全貌,两者为臂丛神经成像较为有效的技术方法,对于臂丛神经病变的诊断即具有十分重要的意义。     

一种新的磁共振快速自旋回波序列

目的 开发一种新的双对比度快速自旋回波(DFSE)序列。 方法 基于双回波序列和快速自旋回波(FSE)序列,探讨DFSE序列的原理,用Visual C++设计可控参数的用户界面,编译调试DFSE序列。在Anke Medical Supervan 1.5T超导MR系统上分别进行FSE及DFSE序列扫描,得到头部及膝部的质子密度加权像(PDWI)及T2WI。 结果 与FSE序列对比,DFSE序列用一个回波链生成PDWI及T2WI,成像速度显著提高,图像质量能够满足临床诊断要求。 结论 与FSE相比,DFSE是一种更快速可行的方法,一次扫描可同时获得PDWI和T2WI,且图像质量具有较好的鲁棒性。     

腰椎SE序列矢状T1WI像扫描时间的缩短方法

目的减少腰椎自旋回波（spin echo，SE）序列矢状T1WI像的扫描时间。方法用两组不同扫描参数对30例正常人行腰椎MRSE序列矢状T1WI像扫描，测量图像第三椎体及相应背景信号强度值，计算信噪比，进行统计学处理。结果两种检查方法的信噪比差异无显著性（P〉0．05）。结论通过改变参数设置可以缩短扫描时间而不影响图像质量。     

T2-weighted magnetic resonance imaging of the liver: comparison of fat-suppressed GRASE with conventional spin echo, fat-suppressed turbo spin echo, and gradient echo at 1.0 T

BACKGROUND: Fat-suppressed T2-weighted gradient and spin echo (GRASE) magnetic resonance imaging in the liver was compared with three other sequences: conventional spin echo (SE), fat-suppressed and respiratory-triggered turbo SE (TSE), and fast field echo (FFE). METHODS: All sequences were applied in 48 prospective patients. Quantitative and qualitative analyses were performed. Biopsy or clinical follow-up established the final diagnosis of the lesions. RESULTS: GRASE showed the second best contrast-to-noise ratio, the second best artifact level, the same lesion detectability as TSE, and very short acquisition time. GRASE and TSE had the highest sensitivity, specificity, and accuracy. CONCLUSION: Fat-suppressed GRASE offers a fast and accurate method for imaging the liver.     

Hepatic MR imaging: comparison of RARE derived sequences with conventional sequences for detection and characterization of focal liver lesions

Background: We compared two T2-weighted turbo spin echo (TSE) sequences with a T2-weighted conventional SE (CSE) sequence to determine whether sequences derived from rapid acquisition with relaxation enhancement such as TSE could replace CSE for the detection and subsequent characterization of focal liver lesions. Methods: A total of 55 consecutive patients with 107 liver lesions underwent magnetic resonance imaging examinations at 1.5 Tesla, with a constant imaging protocol. TSE pulse sequences were acquired with eight echo trains (repetition time [TR], 4718 ms; echo time [TE], 90 ms; acquisition time [TA], 4.03 min; and a symmetric k-space ordering scheme) and 11 echo trains (TR, 4200 ms; TE, 140 ms; TA, 4.40 min; and an asymmetric k-space ordering scheme) and compared with CSE (TR, 2300 ms; TE, 45/90 ms; TA, 9.53 min). Images were analyzed qualitatively by scoring image quality and artifacts and counting focal liver lesions by independent reading with consensus obtained for discrepancies. Quantitative analysis was performed by measuring signal-to-noise (S/N), contrast-to-noise (C/N), and tumor–liver signal intensity (T/L) ratios. Results: T2-weighted TSE sequences provided better subjective image quality and reduced artifacts as compared with the T2-weighted CSE sequence. CSE and TSE sequences exhibited no statistically significant differences in liver S/N, lesion–liver C/N (CSE TE, 90 ms: 18.6 ± 14.0; TSE TE, 90 ms: 16.5 ± 12.9) and the detectability of focal liver lesions. Heavily T2-weighted TSE with a TE of 140 ms allowed correct characterization of focal liver lesions based on a T/L ratio of 3.0 in 84% of patients. Conclusions: T2-weighted TSE sequences are as suited as CSE for the detection (TE, 90 ms), and appear to be superior for the characterization (TE, 140 ms), of focal hepatic lesions. Whether a single sequence, such as a double-echo TSE or a single-echo TSE sequence with a TE between 110 and 120 ms, might perform both functions as well or better than CSE is unknown. However, because of time savings, TSE eventually may be preferred over CSE. Received: 13 December 1994/Accepted after revision: 31 March 1995     

Motion artifact control in body MR imaging.

The mechanisms involved in the generation of motion artifacts in MR imaging are complex and depend both on the type and direction of motion as well as on the parameters of the imaging sequence chosen. The methods used to control or reduce motion artifacts are multiple and the appropriate method for use with any given clinical situation will depend on the particular hardware and software of the MR imaging unit, the patient's clinical status, and the specific organ or disease state to be imaged. Some general guidelines for clinical use that are applicable in most scenarios can be defined, although preferences for the different techniques vary. Appropriate T1-weighted images of the upper abdomen and liver can be obtained with breath-hold T1-weighted gradient echo. These images should be acquired with inferior-superior spatial presaturation pulses to reduce vascular pulsation artifact and ghosting. The application of GMN will depend on the individual MR imaging system. If sufficient coverage cannot be obtained with gradient-echo imaging, then conventional T1-weighted images with phase-encoding reordering is suggested. The addition of spatial presaturation pulses (inferior-superior) may be valuable. The use of fat suppression will further improve image quality by reducing ghost artifact and improving CNR, although SNR will decrease. T2-weighted imaging of the upper abdomen will depend greatly on the hardware and software of the MR imaging unit. Recent techniques of breath-hold T2-weighted imaging require faster and stronger gradients, and may not be universally available. If available, these techniques provide excellent anatomic detail, although image contrast (e.g., liver to spleen) may decrease. Respiratory-triggered FSE techniques are the preferred method of imaging in most centers, because the imaging time is considerably less than conventional T2-weighted imaging whereas the image quality is improved. Liver lesion detection capability of the various techniques is still under study. The addition of fat suppression appears to improve image quality further with an increase in lesion detection. By understanding the principles underlying motion artifacts, one can choose the appropriate method of artifact control tailored for the individual clinical situation. In addition, the recognition of the variable appearances of motion artifacts will prevent interpretive errors and misdiagnoses. Careful attention to motion artifact reduction techniques can greatly improve patient care.     

ACS和BLADE序列在上腹部T2WI中的应用价值对比

目的：比较ACS(AI-assisted Compressed Sensing)序列和BLADE序列在上腹部T2WI的应用价值。方法：对61例磁共振上腹部检查患者分别行BLADE-T2-FSE序列和ACS-T2-FSE序列扫描。由两位医师分别对两组图像中呼吸运动伪影、卷褶伪影、胃肠道蠕动伪影、图像错层情况、胆管和病灶显示清晰度、整体图像质量进行评分；测量并计算两组序列中病灶与肝实质信号强度对比率(Contrast Ratio,CR),并进行统计学分析。结果：ACS序列检查时间10秒,而BLADE序列62秒左右。61例患者共检出75例病灶,其中肝细胞肝癌36例,胆管细胞癌6例,肝血管瘤16例,肝囊肿17例。ACS-T2-FSE序列中各类病灶与肝实质信号的CR均高于BLADE-T2-FSE序列(P均<0.05)；两位医师对图像评分一致性良好,ACS-T2-FSE序列中呼吸运动伪影、卷褶伪影、图像错层情况、胆管和病灶显示清晰度与整体图像质量评分均高于BLADE-T2-FSE序列(P均<0.05)；胃肠道蠕动伪影评分ACS-T2-FSE序列较BLADE-T2-FSE序列略低,但不具有统计学意义(P=0.128)。结论：与常规BLADE-T2-FSE序列相比,ACS技术大幅缩短扫描时间,减少了呼吸运动伪影和图像错层,提高了图像诊断质量,值得推广。     

乳腺磁共振成像扫描序列及扫描方位的选择

目的 探讨常规SE序列、FSE序列和3D-FSEGR序列及不同扫描方位在乳腺病变MRI诊断中作用。方法 40例乳腺肿块性病变常规SE序列T1WI及脂肪抑制FSE序列T2WI分别行轴位及矢状位平扫。注射Gd-DTPA后采用3D-FSPGR序列行矢状位动态增强扫描．之后再采用SE序列行脂肪抑制T1WI轴位、矢状位和(或)冠状位扫描。结果 3种扫描序列均有较高的信噪比及较高的病变与正常组织对比分辨率。SE序列T1WI平扫信噪比优，但病变与正常组织的对比分辨率不及FSE序列T2WI，而动态增强3D-FSPGR序列显示病变最敏感，可显示平扫不能显示或显示不明确的病变，且可根据病变的增强特点及时间-信号强度曲线进行定性诊断。增强后脂肪抑制SE序列T1WI显示病变亦较敏感，但不能行动态增强扫描。3种成像方位中，轴位与矢状位更利于显示病变及病变侵犯胸壁和腋窝淋巴结肿大。结论 动态增强3D-FSPGR是乳腺肿块病变中最有价值的检查序列。轴位与矢状位应作为乳腺检查中的基本位置。     

宫颈癌MRI分期与病理对照研究

目的 探讨宫颈癌磁共振成像(MRI)分期与病理分期的相关性.方法 80例经手术或活检病理证实的宫颈癌患者行盆腔MRI检查,MRI的成像序列包括T1加权像、T2加权像、脂肪抑制T2加权像、弥散加权成像,以及钆喷酸葡胺增强T1加权像.观察肿瘤的位置、信号特征及侵犯范围.将MRI所见与病理结果相对比.结果 MRI对宫颈癌分期总的准确率为88.73%.对宫旁侵犯判断的准确率为92.50%,特异度为91.18%,敏感度为100%.MRI与病理诊断的差异主要与宫旁浸润的评价差异有关.结论 MRI在宫颈癌临床分期中具有很高的准确性,是宫颈癌诊断中重要的影像学手段.     

Fast T2-weighted liver MR imaging: comparison among breath-hold turbo-spin-echo, HASTE, and inversion recovery (IR) HASTE sequences

Background: To evaluate the diagnostic efficacy of fast T2-weighted magnetic resonance (MR) imaging sequences on image quality, hepatic lesion detection, and lesion conspicuity. Methods: Three breath-hold, fast T2-weighted sequences with turbo-spin-echo (TSE), half-Fourier acquisition single-shot TSE (HASTE), and inversion recovery (IR) HASTE techniques were examined for 43 lesions in 20 consecutive patients. Evaluation was performed qualitatively on image quality and lesion detectability and quantitatively on lesion conspicuity by using lesion/liver signal-intensity and contrast-to-noise ratios. Results: Artifacts were significantly less present on the HASTE sequence (p < 0.01). Both TSE and HASTE sequences detected 39 lesions (91% each); the IR HASTE sequence detected 37 (86%). IR HASTE sequence showed a significantly higher signal-intensity ratio than did the others (p < 0.01). Conclusions: Breath-hold TSE versus breath-hold HASTE or IR HASTE is still the most robust sequence in lesion detection, image quality, and lesion conspicuity. However, the HASTE sequence offers good lesion detection and image quality, and the IR HASTE has a better signal-intensity ratio. Received: 15 January 1999/Accepted: 24 March 1999     

口服枸橼酸铁铵在3.0T高场强MR上腹部检查中的初步研究

目的通过使用3.0T磁共振扫描仪对口服枸橼酸铁铵前后进行上腹部成像,研究该对比剂在高场强磁共振上腹部检查中的临床应用价值。方法对9例健康志愿者在服用浓度为7.55mmol/L的枸橼酸铁铵前后使用相同的扫描参数进行横轴位常规T1WI、T2WI成像和磁共振胰胆管成像(MRCP),按不同解剖部位显示情况分别进行评分并进行统计学分析。结果口服对比剂后胃、十二指肠降部及肝左叶边缘的显示在不同序列的横轴位图像上都有显著改善,MRCP对胰胆管的显示也有显著改善,配对秩和检验的结果P<0.05。结论在上腹部高场强磁共振检查中使用枸橼酸铁铵对比剂可以明显改善胃肠道内液体对MRCP图像的影响,对横轴位图像的显示也有明显的改善作用。     

A comparison study between 3D T2-weighted SPACE and conventional 2D T2-weighted turbo spin echo in assessment of carotid plaque

The aim of this study was to compare 3D T2-weighted sampling perfection with application optimized contrast using different flip angle evolutions (T2w SPACE) with conventional 2D T2w turbo-spin echo (TSE) in plaque imaging of carotid artery. 45 patients underwent 3.0-T MRI for carotid arteries imaging. MR sequences included T2w SPACE, T2w TSE, Time of flight (TOF) and T1-weighted (T1w) TSE. The signal intensity of intra-plaque hemorrhage (IPH), lipid-rich necrotic core (LRNC), and loose matrix (LM) were measured and their contrast ratios (CRs) against adjacent muscle were calculated. CRs from T2w SPACE and T2w TSE were compared to each other. CRs of LM, LRNC, and IPH measured on T2w SPACE were 1.74–3.04 (2.44), 0.98–1.66 (1.39), and 1.91–2.93 (2.51), respectively. CRs of LM, LRNC, and IPH on T2w TSE were 1.97–3.41 (2.44), 1.18–1.73 (1.43), and 2.26–3.75 (2.26), respectively. There was no significant difference of CR of the carotid plaques between T2w SPACE and T2w TSE (p?=?0.455). Markedly significant differences of CRs were found between LM and LRNC (p?<?0.001), and between LRNC and IPH (p?<?0.001) on T2w SPACE and T2w TSE. T2w SPACE was comparable with conventional T2w TSE in characterization of carotid plaque.     

Volumetric MR imaging of the liver and applications.

Recent improvements in MR technology have enabled the development of volumetric three-dimensional (3D) imaging methods for fat-suppressed T1-weighted images of the entire upper abdomen with pixel sizes of approximately 2 mm in all dimensions and with acquisition times of less than 25 seconds for breath-hold imaging. When performed with a timing scheme, dynamic contrast-enhanced volumetric imaging of the liver can be performed with selective imaging during the arterial phase and portal venous phase of enhancement. The volumetric data sets can be reconstructed in any oblique plane, enabling improved detection, localization, and characterization of small liver lesions. The combination of high-resolution isotropic pixels and accurate timing also permits angiographic reconstructions of the 3D images, producing MR angiography and venography that can be useful in therapeutic planning, such as for catheter-based interventions or surgical resections or transplantation. Additionally, with use of a hepatobiliary contrast agent such as mangafodipir, T1-weighted volumetric MR cholangiography can be performed in patients with nonobstructed systems for depiction of intrahepatic biliary anatomy.