Application Value of Magnetic Resonance Image in the Diagnosis of Cerebral Cavernous Malformations

目的 分析颅内海绵状血管瘤(cerebral cavernous malformations,CCMs)常规MRI序列表现及MRI磁敏感加权成像(susceptibility weighted imaging,SWI)的诊断价值.资料与方法 回顾性分析50例经病理证实的CCMs 患者的MRI资料,比较常规MRI序列(T1WI和T2WI)和SWI表现、检出率和病灶大小,判断其对CCMs的诊断价值.结果 50例共捡出97个病灶,22个病灶可见短T1信号伴出血,常规MRI对出血病灶具有多种表现形式;75个病灶未见短T1信号不伴出血.49个病灶T2WI灶周具有“铁环征”;97个病灶中有48个病灶在T1WI或T2WI上呈“网格”状或“桑椹”状高、低混合信号;8个病灶T1WI、T2WI均呈高信号;6个病灶T1WI、T2WI均呈低信号;3个病灶T1WI呈等信号、T2WI呈稍低信号.SWI显示的病灶范围包括瘤体及灶周含铁血黄素区域,病灶信号不均匀性降低;SWI上90个病灶显示均匀或不均匀黑色信号,7个病灶显示混杂信号影.T1WI、T2WI、SWI对出血性病灶的检出率均为100％,SWI对非出血性病灶检出率为100％,显著高于T1WI和T2WI(18.6％和40.0％,P＜0.05).SWI显示出血性瘤体大小为(3.3±1.2)cm,显著大于T1WI和T2WI[ (2.0 ±0.6)cm和(2.6 ±0.9)cm,P＜0.05];SWI显示非出血性瘤体大小为(3.1 ±1.1)cm,显著大于T1WI和T2WI[(1.7±0.6)cm和(2.3 ±0.8)cm,P＜0.05].结论 MRI是诊断CCMs的首选方法,常规序列结合SWI序列能提供更准确和更全面的诊断信息.     

磁共振成像在诊断颅内海绵状血管瘤中的应用价值

目的分析颅内海绵状血管瘤(cerebral cavernous malformations,CCMs)常规MRI序列表现及MRI磁敏感加权成像(susceptibility weighted imaging,SWI)的诊断价值。资料与方法回顾性分析50例经病理证实的CCMs患者的MRI资料,比较常规MRI序列(T1WI和T2WI)和SWI表现、检出率和病灶大小,判断其对CCMs的诊断价值。结果 50例共捡出97个病灶,22个病灶可见短T1信号伴出血,常规MRI对出血病灶具有多种表现形式;75个病灶未见短T1信号不伴出血。49个病灶T2WI灶周具有"铁环征";97个病灶中有48个病灶在T1WI或T2WI上呈"网格"状或"桑椹"状高、低混合信号;8个病灶T1WI、T2WI均呈高信号;6个病灶T1WI、T2WI均呈低信号;3个病灶T1WI呈等信号、T2WI呈稍低信号。SWI显示的病灶范围包括瘤体及灶周含铁血黄素区域,病灶信号不均匀性降低;SWI上90个病灶显示均匀或不均匀黑色信号,7个病灶显示混杂信号影。T1WI、T2WI、SWI对出血性病灶的检出率均为100%,SWI对非出血性病灶检出率为100%,显著高于T1WI和T2WI(18.6%和40.0%,P<0.05)。SWI显示出血性瘤体大小为(3.3±1.2)cm,显著大于T1WI和T2WI[(2.0±0.6)cm和(2.6±0.9)cm,P<0.05];SWI显示非出血性瘤体大小为(3.1±1.1)cm,显著大于T1WI和T2WI[(1.7±0.6)cm和(2.3±0.8)cm,P<0.05]。结论 MRI是诊断CCMs的首选方法,常规序列结合SWI序列能提供更准确和更全面的诊断信息。     

MR高分辨磁敏感加权成像在颅脑弥漫性轴索损伤中的应用价值

目的 探讨高分辨磁敏感加权成像(susceptibility-weighted imaging,SWI)序列在颅脑弥漫性轴索损伤(diffuse axonal injury,DAI)诊断中的价值及SWI上病灶数目与患者临床预后的关系.方法 21例经临床及影像学确诊的DAI患者,分别在外伤后15 d内行3.0T MR常规序列(T1WI 、T2WI 和FLAIR)及高分辨SWI序列扫描,并观察患者病灶形态、分布、数目等,对比分析SWI和常规MR序列对DAI病灶显示的敏感性及信号特征,并与哥拉斯哥昏迷计分表(GCS)评分及预后进行相关性分析.结果 21例DAI患者中,MRI常规扫描共发现183个病灶,其中T1WI检出32个,T2WI检出65个,FLAIR检出86个;SWI序列共检出467个病灶.DAI出血灶的分布形态在SWI上表现多样,皮髓质交界区的病灶多呈斑点状或串珠状;脑白质和小脑病灶多呈团状或点片状;基底节、脑干病灶多呈斑片或点状.SWI序列发现病灶数量明显多于常规MR(t = -2.210,P＜ 0.05).SWI显示DAI的病灶数目与患者GCS评分呈负相关(r = -0.849,P＜0.05).结论 SWI对脑内微出血灶的检出明显优于常规MRI,并且病灶的数量与患者GCS评分密切相关,对DAI的诊断和预后判断有很高的价值.     

MR磁敏感加权成像对脑弥漫性轴索损伤的诊断价值

目的 探讨磁敏感加权成像技术(SWI)在脑弥漫性轴索损伤(DAI)中的应用价值.方法 27例DAI患者行1.5 T MR检查,扫描方法为T1WI、T2WI、FLAIR及SWI序列扫描,比较不同序列对DAI脑内病灶的显示率并分析其信号特征,评价SWI在检查和诊断中的作用.结果 27例各序列脑内各部位DAI病灶平均检出数依次为:T1WI 0.35±0.27 、T2WI 1.74±0.81 、FLAIR 3.04±2.11 、SWI 7.25±4.86,SWI检出数最多,共检出DAI出血灶1175个,与T1WI、T2WI和FLAIR的差异有统计学意义(Z值分别为-6.324,-5.752,-4.357,P<0.01),SWI可以显示常规序列不能显示的针尖大小的出血灶,且病灶边界显示更加清晰.DAI出血病灶主要分布在皮髓交界区、基底节、胼胝体、脑干及小脑等区域,SWI图像上表现为大小不等的斑点状、结节状、条索状显著低信号.结论 SWI对DAI出血性病灶的检出具有极高的敏感性,能够检出更多、更小病灶,且病灶显示更加清晰,应作为MR诊断DAI常规序列.     

SWI在出血性弥漫性轴索损伤诊断中的应用

目的 :探讨SWI在诊断出血性弥漫性轴索损伤(DAI)中的影像学表现特点,以提高诊断准确率。方法 :回顾性分析70例经临床及影像学确诊的出血性DAI患者的MRI资料,将SWI与常规MRI(T1WI、T2WI和FLAIR)及DWI对比,评价SWI对出血性DAI检出的优越性。结果:70例SWI均得到明确显示。SWI发现病灶436个,明显多于T1WI显示的98个、T2WI显示的132个、FLAIR显示的236个、DWI显示的302个;SWI典型表现为:脑白质、皮髓质交界区、基底节、胼胝体、小脑上脚、脑干背外侧等易损区散在点状、串珠状、斑点状、团状、点片状显著低信号灶,边界清晰,大小不均呈多灶性。结论:SWI比常规MRI及DWI序列对出血性DAI的检出更敏感,能检出更多微出血灶,结合常规MRI及DWI序列能做出出血性DAI的定性及定量诊断,为出血性DAI的早期诊断及预后评估提供更多帮助。     

磁敏感加权成像对胼胝体损伤的诊断

目的 探讨磁敏感加权成像(susceptibility weighted imaging,SWI)对胼胝体损伤的诊断价值.方法 回顾性分析15例CT检查阴性而MRI检查阳性的胼胝体损伤的MRI图像,所有患者均行高场强1.5T磁共振T1WI、T2WI、FLAIR、SWI横断位及T2WI矢状位扫描,分析各序列胼胝体损伤的信号特征及显示率.结果 胼胝体损伤T1WI为低、略低、稍高信号6例,T2WI、FLAIR为高信号10例,15例SWI均表现为明显低信号,5例患者CT、T1WI、T2WI、FLAIR均未见异常,其中4例SWI诊断为弥漫性轴索损伤,1例诊断为胼胝体等处多发损伤.脑内其他损伤区SWI表现为低信号影.结论 SWI对显示和诊断胼胝体损伤有较高的敏感性和准确性,并能显示常规MRI序列不能显示的微小损伤.     

长骨纤维结构不良的MRI诊断

目的 探讨长骨纤维结构不良的MRI表现特点.方法 回顾分析16例经手术病理证实的长骨纤维结构不良患者的MRI影像资料.结果 与周围正常肌肉信号相比,病变在T1WI表现为均匀等信号4例,等信号为主的等、低混杂信号8例,均匀低信号3例;T2WI显示较均匀高信号3例,不均匀中等信号5例,中等信号为主的等、高混杂信号7例;1例在T1WI及T2WI均显示为均匀低信号.4例可见病灶内线样分隔,分隔在T1WI、T2WI均表现为低信号.注射Gd-DTPA增强扫描,病灶可表现为边缘强化、斑片状强化或不均匀强化.结论 纤维结构不良的MRI表现与病灶内不同病理组织成分相关,且MRI能够提供更全面的影像学信息.     

磁敏感加权成像对脑部恶性肿瘤的诊断价值

目的:探讨磁敏感加权成像(SWI)技术对脑部恶性肿瘤诊断的应用价值.材料和方法:搜集30例经手术及病理证实的脑恶性肿瘤患者资料,其中胶母细胞瘤13例、间变性脑膜瘤6例、恶性室管膜瘤4例、恶性生殖细胞瘤4例、转移瘤3例.全部病例行T1WI、T2WI、增强T1WI及SWI序列检查,对结果进行对比分析.结果:19例病灶内见散在T1WI低信号、T2WI等或高信号灶,无法鉴别坏死或出血,11例病灶内等信号,全部病灶增强T1WI强化不均.SWI序列病灶内可见较T1WI、T2WI异常信号范围更大的低信号出血灶,无异常信号的病灶内出现低信号出血灶,有14例显示低信号肿瘤引流静脉.结论:SWI序列可以显示肿瘤内常规MRI序列无法判断性质或不能显示的出血及肿瘤静脉血管,对恶性肿瘤的诊断具有较大价值.     

MRSWI在脑微出血及脑血管畸形中的应用研究

目的：探讨 MR 磁敏感加权成像(SWI)在不同脑疾病伴微出血(CMBs)及脑血管畸形中的应用及价值。方法回顾性分析76例不同脑疾病伴 CMBs 及25例脑血管畸形的 MRI 资料：(1)将不同脑疾病患者的常规 T1 WI、T2 WI、T2 FLAIR、DWI 显示的 CMBs 数目、敏感性与 SWI 序列比较。(2)评价 SWI 图、最小信号强度投影(MIP)、相位图(Phase)对 CMBs 显示的差异：大小、数目、信号及边界特点。(3)评价 SWI 在不同脑血管畸形诊断中的价值。结果(1)SWI 序列检出 CMBs 1524个,T1 WI、T2 WI、T2 FLAIR、DWI 分别检出 CMBs 294个、87个、361个、391个,对 CMBs 病灶检出敏感性分别为19.3%、5.7%、23.7%、25.7%,多序列 CMBs检出数目及敏感性比较,差异均有统计学意义(P 均<0.05)。(2)SWI、MIP 图分别检出 CMBs 1524个、1539个,两者图像上CMBs 均表现为≤10 mm 类圆形或点状低信号或以低信号为主的混杂信号;Phase 图检出 CMBs 1521个,表现为高信号或以高信号为主的混杂信号;对于 CMBs 大小、数目、边界的显示,MIP 与 SWI 相似,Phase 不及前两者。(3)静脉发育畸形12例,SWI 均可清晰显示“海蛇头”,即多条低信号髓静脉呈辐射状汇入粗大的引流静脉;毛细血管扩张症6例,SWI 均表现为多发小圆形均匀低信号或“靶征”,MIP 特异性表现为连续层面病灶与小静脉相连;动静脉畸形2例,1例 SWI 仅显示迂曲小血管及粗大引流静脉;另1例 SWI 清晰显示了瘤巢及粗大引流静脉呈高信号汇入乙状窦;海绵状血管瘤4例,SWI 均呈“桑葚状”,病灶中心呈不均匀斑点状高低混杂信号,周边伴低信号环。Sturge-Weber 综合征1例,MIP 图可见与 CT 一致脑回样钙化所致的低信号影,大脑半球及小脑幕附近显示大量迂曲增宽、粗细不均静脉血管。结论SWI 可作为 CMBs 检出的重要序列。不同的脑血管畸形在 SWI 序列有特异性表现,结合 MRI 平扫有助于作出准确诊断。     

CT与MR检查在脑血管畸形诊断中的临床价值

目的 探讨CT、MRI检查在脑血管畸形诊断中的价值.方法 回顾性分析25例经临床或病理诊断的脑血管畸形CT和MRI资料,比较CT和常规MRI序列(T1 WI、T2 WI、FLAIR)、MRA及MRI磁敏感加权成像(susceptibility weighted imaging,SWI)的影像表现、检出率,判断其诊断价值.结果 25例病例中动静脉畸形16例、海绵状血管瘤7例和静脉畸形2例.16例动静脉畸形中3例CT平扫未见异常,13例CT平扫表现为边界不清的混杂密度影和迂曲扩张的血管影.而常规MRI和MRA上均可见扩张迂曲的异常血管团影.在SWI上均可见斑点状、迂曲的条状低信号影.7例海绵状血管瘤4例为单发,3例为多发,共检出病灶73个.CT平扫检出5例19个病灶.常规MRI检出51个病灶,“桑椹”状高低混杂信号及“铁环征”较具有特征性.在SWI像上检出病灶73个,其中69个为低信号,4个为以低信号为主的混杂信号.2例静脉畸形均为单发,CT平扫、常规MRI检查均无特异性表现,SWI表现为放射状异常信号影聚集,呈“水母头”征.结论 CT检查对合并急性出血、钙化的病灶敏感,但对无出血、无钙化及微出血的小病灶检出率低,定性困难.MRI常规序列结合SWI序列扫描能提供更多、更准确的信息,为诊断脑血管畸形的最佳检查方法.     

Functional MRI of the patellofemoral joint: comparison of ultrafast MRI,motion-triggered cine MRI and static MRI

In recent years ultrafast gradient echo sequences have been used in MRI that allow functional MRI studies of the joints during active motion in an acquisition time of seconds. To evaluate the feasibility and usefulness of ultrafast MRI (u), patellar tracking from 30° of flexion to knee extension (0°) was analysed and compared with motion-triggered cine MRI (m) and a static MRI technique (s). The different imaging methods were compared in respect of the patellofemoral relationship, the examination time and image quality. Eight healthy subjects and four patients (in total 18 joints) with patellar subluxation or luxation were examined. Significant differences between the static MRI series without quadriceps contraction and the functional MRI studies (motion-triggered cine MRI and ultrafast MRI) were found for the patellar tilt angle (PTA: P _m/s = 0.01; P _u/s < 0.01). In the dynamic joint studies there was no statistical difference of the regression coefficients between the motion-triggered cine MRI studies and the ultrafast MRI studies (P _m/u = 0.8). The findings of the functional MRI studies compared with the static MRI images were significantly different for the lateralisation of the patella, expressed by the lateral patellar displacement (LPD: P _m/s < 0.01; P _u/s = 0.01) and bisect offset (BSO: P _m/s = 0.01; P _u/s < 0.05). No significant differences in patellar lateralisation were found between motion-triggered cine MRI and ultrafast MRI (LPD: P _m/u = 0.89; BSO: P _m/u = 0.33). Ultrafast MRI was superior to motion-triggered cine MRI in terms of the reduction in imaging time and improvement of the image quality. Correspondence to: C. Muhle     

Neuromelanin-Sensitive MRI

Abstract   The basics and the technique of magnetic resonance imaging (MRI) for visualizing the neuromelanin present in dopaminergic and noradrenergic nuclei in the substantia nigra pars compacta (SNc) and locus caeruleus (LC) are introduced. Neuromelanin, a black pigment produced during catecholamine synthesis, has paramagnetic T1-shortening effects. Conventional MRI techniques fail to depict the contrast generated by neuromelanin, but neuromelanin-sensitive T1-weighted fast spin echo technique at 3 T allows the direct visualization of the SNc and LC as hyperintense areas. In Parkinson's disease, neuromelanin-related signals from the SNc and LC are diminished, suggesting neuronal degeneration in both the nuclei. In depression and schizophrenia, signals from the LC are reduced while those from the SNc are augmented, suggesting monoamine and dopamine hypotheses, respectively. Neuromelanin-sensitive MRI is a promising technique to elucidate the pathologic or functional changes in the catecholamine neurons of the brain stem that occur in degenerative and psychiatric diseases.      

Obstetric MRI

Ultrasound is the imaging modality of choice for pregnant patients. However, MRI is increasingly utilized in patients in whom the sonographic diagnosis is unclear. These include maternal conditions unique to pregnancy such as ectopic pregnancy, placenta accreta, and uterine dehiscence. MRI is also being increasingly utilized in the assessment of abdominopelvic pain in pregnancy, in particular in assessment for appendicitis. Fetal MRI is performed to assess central nervous system (CNS) abnormalities and patients who are considering fetal surgery for conditions such as neural tube defects, congenital diaphragmatic hernia, and masses that obstruct the airway. In the future, functional MRI and fetal volumetry may provide additional information that can aid in our care of complicated pregnancies.