MRI半剂量动态增强扫描对垂体微腺瘤的诊断分析

目的:探讨MRI半剂量动态增强扫描技术对垂体微腺瘤的诊断价值.方法:回顾性分析经手术及临床综合诊断明确的29例垂体微腺瘤的MRI平扫及半剂量动态增强扫描资料.结果:29例垂体微腺瘤中,病灶大小小于5mm 18例,5～10mm 11例.平扫16例T1WI可见低信号影;无明显异常信号8例(其中6例病灶直径小于5mm);垂体形态异常5例;而半剂量动态增强扫描均发现病灶,表现为动态早期稍低信号影.结论:半剂量动态增强扫描MR对垂体微腺瘤的诊断有极高的应用价值,尤其是动态增强早期扫描最为敏感.     

垂体微腺瘤MRI半剂量动态增强扫描影像学分析

目的：分析25例垂体微腺瘤MRI半剂量动态增强扫描的影像学征象及动态增强信号强度一时间曲线图的特点,总结垂体微腺瘤的影像学诊断要点。方法：对25例经过临床综合诊断确诊的病例．行MRI平扫及半剂量（0．05mmol／kg）动态增强扫描,并利用工作站后处理功能．绘制出动态增强信号强度-时间曲线图。结果：平扫垂体信号异常的20例．主要T1wI呈稍低信号T2wI呈稍高或稍低信号。平扫垂体信号无异常的5例;25例均进行半剂量（0．05mmol／kg）动态增强扫描．动脉早期（25～35s）呈低信号的病例8例,动脉中期（35～76s）呈低信号的病例16例·动脉晚期（76～120s）呈高信号的病例1例。结论：半剂量MRI半剂量动态增强扫描在诊断垂体微腺瘤的敏感性、检出率都好于其它检查,有较高的临床价值。     

匙孔动态增强MRI对45例催乳激素分泌型垂体微腺瘤的诊断

目的:评价匙孔(keyhole)动态MRI对催乳激素(prolactin,PRL)分泌型垂体微腺瘤的诊断价值.材料和方法:回顾性分析45例经手术或临床证实的PRL分泌型垂体微腺瘤的动态增强MRI影像表现,由两位有经验的影像科医师阅片,不告知临床及实验室检查结果的情况下作诊断,垂体内见有粟粒、结节或片块状异常信号者作肯定微腺瘤诊断;垂体内信号不均匀者作可疑微腺瘤诊断;垂体内信号未见异常者不作微腺瘤诊断.结果:无临床及实验室检查参考时,可肯定垂体微腺瘤诊断者18例;可疑垂体微腺瘤诊断者26例;不作垂体微腺瘤诊断者1例.结合临床及实验室检查诊断正确率达97.8%.结论:keyhole动态MR对PRL分泌型垂体微腺瘤有较高的诊断价值,临床和实验室检查怀疑PRL分泌型垂体微腺瘤而MR平扫阴性的患者应常规作动态增强MR检查.     

动态增强MRI在垂体微腺瘤诊断中的应用研究

目的　探讨动态增强MRI在垂体微腺瘤诊断中的价值。资料与方法　对 6 2例经临床及实验室检查诊断为垂体微腺瘤患者进行MRI平扫、Gd DTPA动态增强扫描及常规延迟增强扫描并分析其MRI信号特征。结果　MRI平扫、动态增强和常规延迟增强扫描微腺瘤检出率分别为 4 6 .8% (2 9/ 6 2 )、88.7% (5 5 / 6 2 )和 6 4 .5 % (4 0 /6 2 )。 3种不同的扫描方法病灶检出率有显著差异 (P <0 .0 1)。结论　MRI动态增强扫描、常规延迟增强扫描提高了病灶的检出率 ,其中以动态增强扫描病灶检出率最高。动态增强扫描可作为MRI诊断垂体微腺瘤的首选强化方法     

MRI动态扫描对垂体微腺瘤的诊断价值

目的:探讨MRI动态扫描对垂体微腺瘤的诊断价值。材料与方法:垂体微腺瘤患者30例均经PHILIP 1.0 NT型MR机行常规矢状面、冠状面T_1WI和T_2WI检查,而后全部又经动态扫描。结果:本组30例的病灶在平扫中,T_1WI呈低信号、T_2WI呈高信号者25例;T_1WI呈等信号、T_2WI呈高信号者3例;T_1WI和T_2WI均呈等信号者1例及高信号者1例。微腺瘤形态征象有垂体柄偏斜(25例)、垂体中央向上膨隆(2例),鞍底下陷(2例),以及瘤内出血(1例),动态扫描后,病灶不增强而正常腺体增强且边界清楚者29例,仅有1例病灶内出血且边界不清楚。结论:MRI动态扫描对垂体微腺瘤的诊断敏感性显著高于平扫,而且它可完整地观察早期正常垂体的增强表现与垂体微腺瘤的增强延迟表现,因而,它有助于对垂体微腺瘤的准确定位,提高诊断准确率。     

动态MRI对垂体微腺瘤的诊断价值

目的　评价匙孔动态MR对垂体微腺瘤的应用价值。方法　回顾性分析临床有头痛、闭经、泌乳、过度肥胖或肢端肥大等症状的 53例经手术和临床证实的垂体微腺瘤的MR影像资料 ,由2位有经验的影像科医师在相互隔离、不知道临床及实验室资料的情况下对 53例的动态MRI、MR传统增强及冠状面平扫T1 WI分级 ,并得出一致结果。分级标准为 :0级 :垂体内未见异常信号 ;Ⅰ级 :垂体内信号不均匀 ;Ⅱ级 :垂体内见有粟粒、结节或片块状的异常信号区。将动态MR、MR传统增强及平扫图像分级的结果进行比较。结果　本组动态MR垂体内未见异常信号者 (0级 ) 1例 ,垂体内信号不均匀者 (Ⅰ级 ) 2 9例 ,垂体内见有粟粒、结节或片块状的异常信号区者 (Ⅱ级 ) 2 3例 ;MR传统增强 0级 2 6例 ,Ⅰ级 1 7例 ,Ⅱ级 1 0例 ;MR平扫 0级 39例 ,Ⅰ级 1 0例 ,Ⅱ级 4例。本组动态MR检出率为 98 1 % ;传统增强MR检出率为 51 9% ;MR平扫检出率为 2 6 4%。行×列 χ2 检验 ,P <0 0 0 5。表明动态MR能明显提高微腺瘤显示的级别 ,且差异有非常显著性意义。结论　动态MR能明显提高垂体微腺瘤诊断的可靠性 ,降低MR图像模棱两可的出现率。临床怀疑垂体微腺瘤而MR平扫阴性者 ,动态MR应列为常规检查     

动态对比增强MRI诊断《5 mm垂体微腺瘤的应用研究

目的　探讨动态对比增强磁共振成像 (DCE -MRI)动态扫描时间的选择对诊断 <5mm垂体微腺瘤的影响。方法　对 3 6例经手术病理及临床治疗证实的垂体微腺瘤的MRI进行分析。使用Philips 1.5T超导磁共振仪。所有患者在常规平扫后 ,均进行DCE -MRI冠状位扫描。结果　 3 6例均呈阳性结果 ,<5mm的垂体微腺瘤由于瘤体微小平扫有时难以发现病灶 ,本组平扫 19例未发现信号学改变 ;7例未发现形态学改变 ,而动态增强扫描均能发现病灶 ,明确诊断。结论　DCE -MRI对 <5mm垂体微腺瘤的诊断极有价值 ,尤其是动态早期 ,在 3 3 .5s之前表现最为敏感 ,它是目前MR诊断垂体微腺瘤的最佳扫描方法。     

K空间中心部分采集技术的垂体动态增强扫描

目的：研究ｋｅｙｈｏｌｅ技术的临床应用，探讨正常垂体增强时间及增强方式；对比动态与非动态扫描垂体微腺瘤的显示情况。材料与方法：随机选择３０例女性无垂体病变及症状者作为对照组；垂体微腺瘤组３０例。ｋｅｙｈｏｌｅ动态增强扫描方法为０．１ｍｍｏｌ／ｋｇ钆喷酸葡胺静脉注射后第１０秒钟开始动态扫描垂体。结果：正常垂体组显示垂体在开始注射造影剂后２７秒开始从垂体柄向腺垂体逐步强化，７５秒时达到最高持续水平，呈均匀高信号。动态增强扫描显示垂体微腺瘤２８例，常规增强扫描显示１９例。增强前、后呈相对低信号。常规增强扫描阴性病例，动态增强扫描显示病灶逐渐强化，延迟后期呈等信号。结论：动态ｋｅｙｈｏｌｅ技术能显示正常垂体增强时间及方式，能更敏感地发现垂体微腺瘤。     

垂体微腺瘤不同增强方式MRI的诊断价值

目的 :探讨注射对比剂后不同增强方式对垂体微腺瘤的诊断价值。方法 :对 5 6例垂体微腺瘤患者先行矢状面及冠状面T1WI和T2 WI扫描 ,然后行GD DTPA冠状面T1WI动态增强扫描和常规延迟增强扫描 ,3 0min后再行冠状面T1WI延迟增强扫描。结果 :5 6例微腺瘤中平扫显示 13例 ,动态增强显示 5 5例 ,常规延迟增强显示 48例 ,延迟增强显示 3 3例。其中动态增强清楚显示 47例 ,常规延迟增强清楚显示 2 6例 ,延迟增强清楚显示 14例 ,三者检出率比较 ,差异有统计学意义。结论 :动态增强扫描与常规延迟增强可明显提高垂体微腺瘤的检出率 ,具有较高诊断价值 ,延迟增强扫描检出率较低 ,不适宜常规应用。     

脑垂体微腺瘤MRI动态增强扫描技术的探讨

目的：探讨脑垂体微腺瘤在MRI动态增强扫描技术中的应用价值。方法：回顾性分析脑垂体动态增强扫描36例，采用GE Signa Contour 0．5T超导型MRI仪，先行常规矢状面SET1和冠状面SET1、FSET2平扫，然后手动推注造影剂马根维显，成人剂量0．1ml/kg，选择FSET1序列，进行快速连续5期增强扫描。结果：每期扫描时间约32—35秒。第1期(动脉期)垂体柄首先显示强化；第2-4期(静脉期)垂体呈逐渐强化并达最高峰值；第5期(毛细血管期)垂体强化程度开始逐步下降。结论：MR动态增强扫描技术是诊断脑垂体微腺瘤的重要手段之一。并可观察造影剂在垂体强化的动态过程，为诊断提供有价值的参考信息。     

Gadolinium DTPA enhanced MR imaging of ACTH-secreting microadenomas of the pituitary gland

Gadolinium diethylenetriamine pentaacetic acid (DTPA) enhanced magnetic resonance imaging was performed in eight patients with Cushing disease and surgically proven pituitary microadenomas. A 1.5 T scanner was used with 3 mm contiguous slices. Short repetition times (TR), short echo times (TE), and long TR, long TE sequences were obtained before and serially after intravenous administration of Gd-DTPA. Three of eight (38%) microadenomas were undetectable both without and with Gd-DTPA: one post-Gd-DTPA scan was false positive on the side opposite the adenoma. Hemihypophysectomy based on a petrosal sinus adrenocorticotropic hormone (ACTH) gradient cured all three patients. Two microadenomas (25%) were visible as hypointense foci following Gd-DTPA but not on unenhanced scans. The remaining three microadenomas (38%) were seen before and after Gd-DTPA on T1-weighted images. In this small series of ACTH-producing microadenomas, one-third were seen on unenhanced 1.5 T scans, one-third were seen only after Gd-DTPA, and one-third were not imaged even with Gd-DTPA enhancement.     

国产钆喷酸葡胺在脑肿瘤诊断中的作用

目的：探讨国产钆喷酸葡胺在脑肿瘤诊断中的价值。材料和方法：回顾分析８２例脑肿瘤的ＭＲＩ增强表现,其中脑胶质细胞瘤２８例;脑膜瘤１３例;垂体微腺瘤１６例;脑转移瘤１５例;颅咽管瘤２例;松果体瘤２例;三叉神经瘤２例;听神经瘤３例;颅底脊索瘤１例。结果：８２例脑肿瘤病人注射造影剂后,有轻度强化９例,中度强化２９例,明显强化２３例,增强效果达７４．４％,其中脑膜瘤、胶质细胞瘤、脊索瘤强化明显;垂体微腺瘤不强化,而正常垂体组织强化明显,从而把肿瘤组织勾描清楚,与ＣＴ的增强表现相类似。增强病例中有轻微反应３例。结论：国产钆喷酸葡胺在脑肿瘤诊断中是一种较为理想的造影剂     

Gd-DTPA增强的MRI在脑转移瘤诊断中的应用

目的探讨Gd-DTPA增强MRI对脑转移瘤的诊断价值及意义。方法回顾分析100例脑部转移瘤病人的平扫和增强MRI资料。结果100例脑转移瘤病人,平扫检出198个转移病灶,增强扫描检出354个转移病灶。平扫检出坏死囊变病灶85个,增强扫描检出183个。平扫检出病灶最小直径0.8cm,增强扫描检出病灶最小直径0.3cm,98例增强后可清晰显示病灶边界。16例没有症状的病人平扫7例未显示病灶,增强后均发现有转移病灶。结论Gd-DTPA是一种安全的MRI对比剂,增强MRI在显示脑转移瘤的大小、数目、边界、内部结构及位置等方面具有明显优势,可以帮助早期诊断。     

Staging and re-staging of soft tissue sarcoma using MRI. Usefulness of contrast media

PURPOSE: This study aims to evaluate the usefulness of paramagnetic contrast medium (Gadolinium) in the staging and re-staging of soft tissue tumors using Magnetic Resonance Imaging (MRI). MATERIAL AND METHODS: Sixty patients affected by soft tissue sarcoma of different histotype were retrospectively evaluated. Age ranged from 23 to 78 years. Data were obtained from the musculoskeletal tumor database of our Department of Radiology and cases from the last 7 years (1993-1999) entered this study. All the patients were submitted to ultrasound (US) and to routine and enhanced MR examinations (SE T1-weighted and Fast-SE T1 and T2-weighted before and after fat saturation pulse; GE T2-weighted sequences). At least two different scan planes were obtained depending on the major axis of the lesion. Once imaging information had been obtained all the patients underwent surgery and histology. After surgery, the mean follow-up period was 18 months. Paramagnetic contrast medium (0,2mmol/Kg) was administered in all the MR follow-up examinations. RESULTS: Lesions included adipose histology in 15 cases; muscular histology in 12 cases; fibro-hystiocitic histology in 20 cases; synovial histology in 8 cases; mixed histology in 5 cases. Excluding lesions with mainly adipose content showing obvious high signal intensity on T1-weighted sequences, the other lesions rarely presented MR features specific to histological category also after contrast medium administration. In all the cases MRI allowed an accurate definition of the lesion boundaries to exclude or demonstrate neighbor region invasion. In 11 cases, MRI was able to demonstrate the presence of a recurrent tumor. In 2 out of 11 cases, recurrences were detected out only after intravenous administration of Gadolinium, plain MRI having failed to recognize them. DISCUSSION AND CONCLUSIONS: Despite the absence of specific MRI signs of the different soft tissue tumor histotypes also after Gadolinium administration, MRI remains the best imaging technique to establish the exact morphology of the lesions and to establish the invasion of the neighbor regions by the tumors. The presence of regional spreading of the tumor has to be considered a sign of malignancy. During the follow-up, the use of Gadolinium allows the MR examinations to reach high sensitivity levels and makes it also possible to recognize local recurrences of a very small size. Considering our experience we recommend, whenever a follow-up of resected soft tissue tumors is requested, to perform MRI examination before and after intravenous Gadolinium administration.     

Gd—DTPAMRI在心绞痛中的作用

目的：探讨Ｇｄ－ＤＴＰＡ增强ＭＲＩ在心绞痛中的作用。材料和方法：２２例心绞痛作Ｇｄ－ＤＴＰＡ增强前后ＭＲＩ检查,其中１６例作冠状动脉造影检查,１１例作ＳＰＥＣＴ检查。结果：增强ＭＲＩ上,１８例（８２％）可见局部异常强化信号,其部位与临床ＥＣＧ吻合,与ＣＡ、ＳＰＥＣＴ所示心肌缺血部位一致。在ＭＲＩ上的异常强化信号与冠状动脉狭窄、ＳＰＥＣＴ显示灌注缺损密切有关。结论：Ｇｄ－ＤＴＰＡＭＲＩ为心绞痛的诊断提供有价值的依据。     

Gd-DTPA in clinical MR of the brain: 2. Extraaxial lesions and normal structures

Fifteen patients with suspected extraaxial tumors were evaluated with MR before and after intravenous injection of Gadolinium-DTPA (Gd-DTPA). Meningiomas (7), neurinomas (4), chordomas (2), a previously irradiated dural metastasis, and a giant aneurysm were studied. All the lesions except the dural metastasis enhanced. In two patients with asymptomatic meningiomas, the use of Gd-DTPA with MR allowed definitive diagnosis of the lesions when the routine MR did not. Gd-DTPA also provided improved definition of intracranial tumor margins, produced differential enhancement of dura and nasopharyngeal mucosa from tumor, and caused enhancement of the choroid plexus, some venous structures, the pituitary gland, and its stalk. The enhancement of the pituitary suggests a role for Gd-DTPA in the diagnosis of microadenomas. Routine T2-weighted images without Gd-DTPA were useful in differentiating neurinomas from meningiomas. Judicious use of Gd-DTPA should improve the ability of MR to detect extraaxial lesions, delineate their extent, and characterize their perfusion.