低场MR增强扫描对脑转移瘤的诊断价值

目的：探讨低场MR增强扫描对脑转移瘤的诊断价值.方法：回顾分析70例脑部转移瘤病人用0.5T超导型磁共振扫描仪做的平扫和Gd-DTF＇A增强扫描的MRI征象.结果：70例脑转移瘤病人,平扫检出118个转移灶,Gd-DTP＇A增强扫描检出239个转移灶.平扫检出最小病灶直径0.9 cm,增强扫描栓出最小病灶直径0.2 cm.结论：低场磁共振Gd-DTPA增强扫描既能发现平扫难以发现的脑转移瘤,又可以准确发现微小和特殊部位的转移灶,同时又可以明确病灶形态、边缘以及内部情况.为临床治疗方案的确定提供可靠依据.     

MRI增强及延迟扫描在脑转移瘤诊断中的应用

目的：进一步探讨MRI T1WI增强及延迟扫描在脑转移瘤诊断中的应用。材料和方法：回顾性分析近两件来经临床或手术病理证实的48例脑转移瘤MR图像，采用平扫、增强及增强后延迟扫描，比较增强前后及延迟扫描后病灶显示情况。结果：①平扫发现病灶直接征象约占60%。②增强后除1例强化不明显外，其余47例均见不同程度和形式的强化，较平扫时更清楚显示病灶形态、大小、边界、浸润范围。有17例显示出平扫无水肿、未显示的65个病灶。③延迟8-10min扫描病灶显示更清楚者17例，比增强后即时扫描增多者10例，共28个病灶。结论：临床疑有脑转移瘤而行MRI检查的病人，增强扫描应成为常规，它能为诊断和治疗方法的选择提供更为丰富的资料，而增强后的延迟扫描，能提供更多，更全的信息，在脑转移瘤的诊断中，有一定价值。     

国产Gd-DTPA大剂量增强MRI探查脑转移瘤的临床研究

目的探讨国产Gd-DTPA三倍量（0.3mmol/kg）增强MRI检查脑转移瘤时病灶体积与病灶检出的关系。方法用国产Gd-DTPA大剂量增强MRI检查70例脑转移瘤患者。先行平扫,然后静脉注射常规量(0.1mmol/kg)国产Gd-DTPA。注射后即刻行T1WI扫描、20min后行延迟扫描。距第一次注射30min后,再注射0.2mmol/kg的Gd-DTPA,从而达到累积剂量0.3mmol/kg。第二次注射后即刻及20min后分别行T1WI扫描。对MR扫描所见进行定性、定量分析。结果三倍量增强比常规量增强扫描发现了更多的转移病灶（86→363,P＜0.01）。对于直径大于10mm的转移瘤病灶,三倍量增强的检出率和其它扫描序列之间没有显著性差异。而对于直径小于10mm的转移瘤病灶,三倍量增强的检出率和其它扫描序列之间有显著性差异（P＜0.05）。尤其对于直径小于5mm的病灶,三倍量增强扫描可以检出89.8%～97.8%的病灶,而常规量增强扫描仅能检出0.4%～0.9%的病灶（P＜0.01）。结论国产Gd-DTPA三倍量(0.3mmol/kg)增强可提高脑转移瘤病灶的检出率,尤其对于直径小于5mm的病灶效果更好。     

脑内结核瘤Gd-DTPA增强MRI表现特点

目的总结和分析脑内结核瘤在Gd-DTPA增强MRI上的表现特点. 资料与方法对24例脑内结核瘤患者进行平扫和Gd-DTPA增强扫描,比较和分析平扫及增强扫描MRI上的表现特点,包括病灶检出数目、分布情况、病灶的形态、信号特点等.结果结核瘤在Gd-DTPA增强扫描自旋回波T1WI上强化明显,呈结节样或环形强化,有多个病灶聚合成团的特点;病变与周边组织分界清楚.结论脑内结核瘤在增强MRI上有一定的特征性表现,Gd-DTPA增强MR检查较平扫更敏感,能早期发现脑内结核瘤.     

增强FLAIR T2WI诊断脑膜转移瘤的价值

目的:探讨脑膜转移瘤的MRI表现及增强后FLAIR序列T2WI的诊断价值。方法:回顾性分析20例脑膜转移瘤患者的病例资料,其中硬脑膜转移瘤5例,软脑膜转移瘤15例。所有病例行常规MRI平扫及SE T1WI和FLAIR序列T2WI增强扫描并进行对比分析。结果:MRI平扫检出6例,病灶边界均显示不清;MRI增强扫描检出所有病例,SE-T1WI上病变主要表现为脑膜的线状和/或结节状强化,FLAIR T2WI对软脑膜转移瘤病灶范围的显示更清楚,可鉴别强化的血管与病变。结论:MRI增强扫描是诊断脑膜转移瘤的重要检查方法,增强后FLAIR序列T2WI与SE T1WI同时使用,可提高对软脑膜转移瘤的检出率及诊断准确性。     

脑转移瘤MRI增强扫描的诊断与鉴别诊断

目的 :评价磁共振增强扫描对脑转移瘤诊断与鉴别诊断的价值。方法 :回顾性地分析了 35例经临床及手术病理证实的脑转移瘤 ,总结了其平扫和增强扫描的MRI征象 ,并将增强新后发现的病灶个数进行配对t检验。结果 :单纯幕上双侧大脑半球内发现病灶的有 2 1例 ,平扫发现 4 3个病灶 ,增强扫描发现 91个病灶 ;单纯幕下双侧小脑半球内发现孤立性病灶者有 6例 ,平扫 6个病灶 ,增强扫描 8个病灶 ;幕上幕下均发现病灶者有 8例 ,平扫发现 2 7个病灶 ,增强扫描有6 0个病灶。增强扫描前后病灶均数的统计分析t值为 2 347,P <0 0 5。结论 :Gd DTPA增强扫描更好地展示了平扫时不能显示的病灶 ,对脑转移瘤的诊断和鉴别诊断有重要的临床价值和意义。     

单发脑转移瘤的MRI诊断

目的: 评价MRI诊断单发脑转移瘤的价值.材料和方法: 回顾性分析38例单发脑转移瘤的临床和MRI表现,病例均经平扫和增强扫描.结果: 38例中,原发于肺癌27例,50岁以上33例;发病过程突然、短期内出现中枢神经障碍症状30例;病灶位于幕上34例,其中25例位于灰、白质交界区.病灶直径>1.0cm时瘤周水肿常较显著.T1WI-FLAIR显示病灶欠清或不清13例,FRFSE-T2WI、T2WI-FLAIR显示欠清或不清楚的分别为5例、2例,增强扫描均清楚显示病灶.结论: MRI增强检查是诊断单发脑转移的最佳方法.     

MRI增强扫描对脑转移瘤的诊断价值

目的 总结磁共振增强扫描在脑转移瘤诊断中的重要价值。方法 脑转移瘤32例，均经病理和临床证实，全部病例均做了Gd-DTPA增强前后扫描。结果 脑转移瘤单发15例，多发17例，发生在幕上26例，幕下6例，幕上幕下并存4例。病灶最大径在0．5cm～6cm，平均2．4cm。发现病灶数：T1WI40个，T2WI56个，增强后发现116个。结论 增强扫描发现的脑转移瘤病灶明显多于平扫，并且能分清病灶与瘤周水肿的界限，从而明确其发生的部位、数目、形态、和大小，结合临床和影像学特征，容易作出正确诊断。     

对比T2FLAIR序列与增强T1WI序列在诊断脑转移瘤过程中的诊断价值

目的：比较增强T1WI及增强T2FLAIR两种序列对脑转移瘤的诊断价值。方法：回顾分析本院2008年9月～2010年3月34例经临床和影像检查确诊为脑转移瘤的患者资料,所有病例均行常规MRI平扫及SET1WI和T2FLAIR增强扫描,比较两种序列上转移瘤的数目、大小和部位以及转移瘤的强化显著性、病变强化区的边界等,并分析两者间偏差的原因。结果：34个病例,MRI平扫共检出129个病灶,增强T1WI发现194个病灶,而增强后T2WI FLAIR共发现185个病灶,4例增强后T2FLAIR较增强后T1WI显示的病灶多,6例增强后T2FLAIR显示的病灶少于增强后T1WI,25例两者显示的病灶相同,增强后T1WI因为脑浅表层血管混淆而漏诊误诊7个病灶,在对比增强后T2FLAIR均可明确诊断。大多数转移瘤在T1WI的强化程度高于T2FLAIR序列。转移瘤的肿瘤与灰质、肿瘤与白质的CR（对比率）以FLAIR序列为高,而转移瘤的肿瘤与灰质、肿瘤与白质的CNR（对比噪声比）以T1WI为高,两者有显著性差异（P〈0.01）。结论：增强后T2FLAIR序列可以有效显示脑转移灶,很好地鉴别大脑浅表部位的血管和转移瘤,增强T1WI序列能更明显地显示转移瘤的强化,两者同时使用,可以提高转移瘤的检出率与诊断准确性。     

低场强MRI强化扫描对脑转移瘤的诊断价值（附49例分析）

目的：研究分析低场强MRI对脑转移瘤的诊断价值。方法：用西门子open 0.2T扫描仪，在常规扫描后再静脉快速推注Gd-DTPA 0.2-0.4ml/kg，选用T1WI条件取相应的断面。结果：49例中单发脑转移瘤11例，多发脑转移瘤38例，共检出瘤体灶133个，强化扫描比平扫多发现49个，病灶发生在幕上的121个，幕下的12个。在133个病灶中，呈弥散快速强化的87个，呈环状结节强化的有46个，均为明显强化性肿瘤。结论：低场强MRI强化扫描对脑转移瘤的病理特点的反应是敏感的。     

Comparative evaluation of computerized tomography/magnetic resonance (1.5 T) in the detection of brain metastasis]

Forty-four patients with small cell carcinoma of the bronchus underwent CT and MR studies of the brain to detect cerebral metastases. All patients were studied with contrast-enhanced CT scans, short (T1-weighted) and long (T2-weighted), spin-echo (SE) and FLASH 90 degrees MR sequences. Gd-DTPA enhanced SE-T1 and FLASH 90 degrees sequences were also obtained. A quantitative comparison of the results was carried out to assess the sensitivity of the different techniques in the detection of brain metastases according to lesion diameter. Metastases were identified in 19/44 patients (43%). All techniques detected the lesions greater than 2 cm; of the metastases less than 2 cm, 63/124 (51%) were detected only by Gd-DTPA SE-T1 and FLASH sequences and 11 more (9%) only by Gd-DTPA SE-T1 scans. All the lesions identified on enhanced CT scans or on T2-weighted images were easily detected by Gd-DTPA scans. CT sensitivity was higher than that of pre-contrast SE-T1 and FLASH studies and only slightly lower than that of T2-weighted images. As for lesions less than 2 cm, Gd-DTPA T1-weighted sequences had the highest detection rate (124 lesions) versus Gd-DTPA FLASH 90 degrees scans (113 lesions) and precontrast T1-weighted scans (45 lesions). When comparing Gd-DTPA SE-T1 and FLASH 90 degrees sequences in the detection of lesions less than 1 cm, we observed that the latter missed 9% of metastases, mainly due to a high rate of magnetic susceptibility artifacts and to lower contrast resolution. Therefore, Gd-DTPA SE-T1 images still remain the most accurate technique in the assessment of cerebral metastases.     

肝脏MR动态增强扫描：Gd-EOB-DTPA与Gd-DTPA的个体内对照研究

目的：比较钆塞酸二钠（Gd-EOB-DTPA）及钆喷酸葡胺（Gd-DTPA）肝脏 MR动态增强扫描腹腔脏器及血管的强化特点,重点比较Gd-EOB-DTPA移行期与Gd-DTPA平衡期的图像特点。方法：本研究为前瞻性、个体内随机对照研究。25例病理证实为原发直肠癌或结肠癌、怀疑肝转移的患者,3天内行2次肝脏 MR 动态增强检查,分别使用 Gd-EOB-DTPA及Gd-DTPA两种对比剂。动态增强扫描的序列相同,包括平扫、动脉期、门静脉期、平衡期（Gd-DTPA）／移行期（Gd-EOB-DTPA）。图像客观评估中,测量各期相图像上血管及肝脾实质的信号强度。以椎旁肌肉的信号为参考,计算相对信号强度（RS）并比较两组间的差异,以及不同期相时肝实质RS的差异。主观评估：读片者主观评价增强扫描各期相图像上,主动脉、门静脉及肝静脉与肝实质的相对信号强度。结果：肝实质的RS：在动脉期Gd-DTPA 组明显高于Gd-EOB-DTPA组（t＝3．006,P＝0．005）;在门静脉期及平衡期／移行期,两组检查的差异无统计学意义（t＝1．788,P＝0．086;t＝0．781,P＝0．442）。Gd-EOB-DTPA检查时,门静脉期肝实质RS明显高于动脉期（t＝－3．014,P＝0．006）,移行期RS与门静脉期的差异无统计学意义。Gd-DTPA检查时,平衡期肝实质RS明显低于门静脉期（t＝5．827,P＝0．000）。主观评估：Gd-DTPA增强扫描平衡期图像上所有患者的主动脉、门静脉、肝静脉均为高信号（100％）;Gd-EOB-DTPA 增强扫描移行期图像上主动脉、门静脉、肝静脉均以低或等信号为主（84％,92％,92％）。结论：Gd-EOB-DTPA动态增强 MR 检查,肝脏实质在门静脉期及移行期呈持续强化,其移行期的图像特征与Gd-DTPA平衡期的图像特征有明显不同,在影像诊断时应予以关注。     

肝脏占位性病变的磁共振成像研究：超顺磁性氧化铁与钆喷替酸葡甲胺的比较

通过与常用造影剂钆喷替酸葡甲胺（Gd-DTPA）的配对实验来评价新型造影剂超磁性氧化铁（SPIO）对有肝占位的检出率和定性诊断能力。材料和方法：53个病例132个肝占位首日行平扫及Gd-DTPA的动态增强扫描,次日行SPIO增强扫描,对照病理及临床随访证实结果,探讨各种占位SPIO增强扫描的强化特点,比较平扫联合Gd-DTPA动态增强扫描与平扫联合SPIO增强扫描的病灶检出率和定性诊断率。结果：SPIO增强扫描良性肝占位的信号随肝实质降低,而恶性肝占位的信号保持不变。平扫联合SPIO增强扫描的病灶检出率和定性诊断率较平扫联合Gd-DTPA增强扫描的略高,但统计学上相差不显著。结论：SPIO强化的原理、强化方式直至临床应用方法、特点与Gd-DTPA均完全不同,两者可相互补充和印证,当Gd-DTPA动态增强扫描定性诊断困难时应积极行SPIO增强扫描。     

Fast spin echo imaging with suspended respiration: gadolinium enhanced MR imaging of liver tumors

Magnetic resonance (MR) imaging of 43 patients with hepatic tumor was performed during suspended respiration using a fast scan spin echo (SE) technique (SE 200/40) with a single excitation. The resulting images were superior in terms of image quality to conventional ones. Due to the lack of soft tissue contrast, 38 patients received Gd-diethylenetriaminepentaacetic acid (DTPA) at 0.05 mmol/kg and serial scanning (CE-MR) was repeated. Twelve of 14 hepatomas showed isointensity or slightly reduced intensity compared with the liver in unenhanced MR. All metastases (nine patients) showed low signal intensity that was statistically significant (p less than 0.001) in differentiating between hepatomas and metastatic liver tumors. With contrast enhanced MR, both hepatomas and metastases showed changes that cannot be further classified until more cases have been examined. In all 12 cavernous hemangioma cases, Gd-DTPA pooling was observed with extremely high contrast, which was a pathognomonic sign. In fact, four cavernous hemangiomas in two patients with a diameter of 1.0 cm were successfully imaged.     

Intradural spinal metastases in pediatric patients with primary intracranial neoplasms: Gd-DTPA enhanced MR vs CT myelography

Recently, the application of intravenous gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) has been shown to improve the detection of intradural extramedullary spinal disease in adults. The ability of Gd-DTPA enhanced magnetic resonance (MR) to detect intradural extramedullary spinal metastases was studied in pediatric brain tumor patients. Spinal MR images before and after intravenous injection of Gd-DTPA were analyzed retrospectively in eight pediatric patients with known intracranial neoplasms and clinically suspected subarachnoid tumor seedings. Contrast enhanced spinal MR was compared with CT myelography in four of these patients. In our pediatric population Gd-DTPA enhanced images revealed tumor seeding not appreciable on noncontrast images. Although CT myelography has been the accepted standard investigation in the evaluation of suspected spinal metastases in children, we found that contrast enhanced MR is equal or superior in sensitivity to CT myelography. Spinal MR also provided information not obtainable via CT myelography. In the future, Gd-DTPA enhanced spinal MR should be considered in the initial evaluation of suspected subarachnoid spinal metastases in pediatric patients with known primary brain tumors.     

肺癌单发脑转移瘤的磁共振表现

目的:探讨肺癌单发脑转移瘤(SBM)的MRI表现,提高对单发脑转移瘤的诊断准确性.方法:回顾性分析经手术病理和临床证实的39例肺癌单发脑转移瘤的MRI表现,分析单发瘤体发生的部位、大小、形态、瘤体出血、瘤周水肿程度和瘤体的强化特点.结果:39个SBM,发生于幕上32例,其中31例瘤体位于皮质和皮质下区,7例位于幕下.增强扫描示病灶呈结节状强化18例,环状强化5例,囊实性强化16例.肺腺癌转移瘤内出血4例(4/5),肺鳞癌脑转移瘤出现囊变或囊实性强化11例(11/21).中重度水肿大多出现在≥2cm的实性或囊实性强化的瘤体(22/39)中.结论:肺癌单发脑转移瘤的MRI表现具有一定的特征性,MRI增强扫描对诊断单发脑转移瘤有重要价值.     

Calvarial and skull base metastases: comparison of nonenhanced and Gd-DTPA-enhanced MR images

Fourteen patients with calvarial metastases were studied with magnetic resonance (MR) imaging before and after intravenous administration of gadolinium diethylenetriamine-pentaacetic acid (DTPA) to evaluate the utility of contrast material enhancement for the detection of calvarial metastatic tumor. MR imaging was also performed before and after enhancement in 60 patients for reasons other than evaluation of metastases or calvarial tumor, to determine the apperance of the normal calvaria with enhancement. The normal pattern of fat distribution in the diploic space was typically symmetric. Except for enhancement of diploic veins and meninges near pacchionian granulations, the normal diploic space did not enhance. Calvarial metastases typically enhanced with Gd-DTPA. Enhanced MR images were superior to nonenhanced studies for detecting subtle intradiploic metastases but were inferior to nonenhanced studies for detecting tumor extension into fat-containing areas. Careful comparison of nonenhanced and enhanced MR images is required for complete evaluation of lesions affecting the calvaria and skull base.     

肿瘤软脑膜-蛛网膜转移的CT、MRI诊断

目的研究肿瘤软脑膜蛛网膜转移的ＣＴ、ＭＲＩ表现,并探讨两种检查方法对该病的诊断价值。方法回顾分析２１例肿瘤软脑膜蛛网膜转移的临床及影像学资料。病变经ＣＴ检查１６例,ＭＲＩ检查７例,其中经两种方法检查者２例。结果全部病例软脑膜蛛网膜下腔均出现病理性强化,其中１０例呈弥漫性,８例呈结节性,３例呈弥漫与结节混合性。弥漫性强化沿脑和脑干表面分布,并延伸入脑沟、脑池;结节性强化病灶数目１个或多个不等,直径０．２～３．０ｃｍ。病变见于基底脑池及相邻蛛网膜下腔者共１８例。伴室管膜结节性强化４例,天幕增厚强化１０例,脑积水１３例,合并脑内转移９例。结论增强ＣＴ和ＭＲＩ对病变的诊断具有重要临床意义,且ＭＲＩ优于ＣＴ。但两者在定性诊断上均有局限性。正确诊断有赖于结合临床资料和影像征象的综合分析     

Magnetic resonance imaging of human cerebral infarction: Enhancement with Gd-DTPA

Summary Five patients (1 female and 4 males) with cerebral infarction of 4 h to 27 months duration were studied 9 times with magnetic resonance (MR) using Gd-DTPA. Spin-echo (SE) MR images (MRI) were obtained before and after the administration of Gd-DTPA, and correlative CT scans were performed on the same day. In 2 cases, 4 h and 27 months after the ictus, there was no enhancement with Gd-DTPA. There was faint enhancement in 2 cases with cerebral infarction of about 24h duration and obvious enhancement in all cases in the subacute stage. Compared with enhanced CT, MR using Gd-DTPA demonstrated more obvious enhancement of infarcted areas. MR enhancement using Gd-DTPA showed a gradual increase and the accumulated Gd-DTPA in infarcted areas slowly diffused to the periphery. MR enhancement with Gd-DTPA is similar to that of enhanced CT, but may be more sensitive in the detection of blood brain barrier breakdown.