脑膜瘤伴瘤周水肿的MRI特征分析

目的:探讨脑膜瘤伴瘤周水肿的机制。方法:49例经手术病理证实的脑膜瘤,回顾性分析伴有瘤周水肿脑膜瘤的MRI特征,用Fisher′s检验比较肿瘤大小、部位、边缘、假包膜征及肿瘤T2WI信号与瘤周水肿发生的关系。结果:肿瘤边缘、假包膜征和肿瘤T2WI信号与脑膜瘤瘤周水肿发生明显相关,P值分别是0.016,0.004 和0.041。结论:脑膜瘤脑界面侵袭性模式和T2WI高信号是提示脑膜瘤发生瘤周水肿的因素。     

髓外硬膜下肿瘤磁共振定性诊断

目的评价MRI对髓外硬膜下肿瘤的诊断价值.方法经手术、病理证实的髓外硬膜下肿瘤69例、83个瘤灶(其中1例转移癌为随访证实),回顾性分析其MRI表现.结果(1)神经源性肿瘤多为T1WI低信号、T2WI高信号,T1/T2得分比值为0.31±0.2,信号不均匀,可见肿瘤血管,增强扫描强化明显,但不均匀;(2)脊膜瘤T1WI多为等信号或稍低信号,T2WI多为等或稍高信号,T1/T2得分比值为0.85±0.19,信号较均匀,增强扫描强化均匀,增强效果不如神经源性肿瘤高,可见脊膜尾征;上述肿瘤的T1、T2、T1/T2得分比值及强化效果经统计学处理差异有显著性;(3)其它脂肪瘤MRI表现具有特征性;转移癌MRI表现可类似脊膜瘤.结论髓外硬膜下肿瘤的MRI诊断价值极高,定位诊断正确率为98.80%,定性诊断正确率为95.2%.     

脑膜瘤MR信号特征在诊治中的价值

目的:探讨脑膜瘤的MRI表现与病理学类型、瘤体质地之间的关系。方法:收集术前行MRI检查并经手术病理证实的63例脑膜瘤患者,将其MR信号特征与病理学类型及其瘤体质地的关系进行对照研究分析。结果:5例血管瘤脑膜瘤表现最典型,在T1WI上呈低或稍低信号,在T2WI上呈高信号,质地软。上皮型、纤维型、过渡型二种脑膜瘤在T2WI上有一定的特征性,22例纤维型脑膜瘤17例(77.3%)呈现为低及稍低信号,质地硬,17例上皮型脑膜瘤11例(64.7%)呈现为等信号,质地较硬,过渡型脑膜瘤介于其两者之间。结论:脑膜瘤的T2WI信号特征可在一定程度上反应脑膜瘤病理学类型及瘤体的质地,对指导神经外科医生的制定治疗万案具有重要的参考价值。     

侵袭性纤维瘤病的CT和MRI表现

目的:探讨CT和MRI在侵袭性纤维瘤病中的诊断价值.方法:回顾性分析20例经手术或病理证实的侵袭性纤维瘤病的CT和MRI表现.结果:瘤体发生于四肢8例,躯干12例,直径2.5～17.0 cm,CT平扫与肌肉对比呈等密度者14例,稍高密度者6例,多数呈渐进性强化,强化不均.瘤体在MRI T1WI上呈等低信号,在T2WI上...     

幕上间变型室管膜瘤的MRI表现

目的: 探讨幕上室管膜瘤的MRI表现及其诊断价值.材料和方法:回顾性分析11例经病理证实间变型室管膜瘤MRI表现.结果:11例肿瘤均位于脑实质,其中侧脑室旁9例.肿瘤呈囊实性9例和实性2例,呈长T1长T2信号,瘤内出血4例,T1WI、T2WI呈结节状高信号,囊变呈更长T2信号,瘤周II度水肿11例.增强扫描实性部分及囊壁不均匀显著增强,囊变及出血区无增强.结论:幕上间变型室管膜瘤的MRI表现有一定的特征性,大囊、多囊变、实性肿块周边出血、实性部分明显增强是瘤体的常见征象.     

鞍区肿瘤的MRI诊断

目的:评价鞍区肿瘤的MRI影像特征,探讨MRI对该区肿瘤的诊断价值。方法:收集经手术与病理证实的鞍区肿瘤63例,其中垂体瘤35例,脑膜瘤6例,颅咽管瘤14例,脊索瘤7例,表皮样囊肿1例。全部病例行MRI平扫检查,52例行增强检查。结果:MRI检查,T1WI上肿瘤大多呈低、等信号或混杂信号,T2WI上呈均匀高信号或不均匀高低混杂信号。结论:MRI对鞍区肿瘤的诊断与鉴别诊断具有重要临床价值。     

MRI对侵袭性纤维瘤病的诊断价值

目的:探讨MRI对侵袭性纤维瘤病术前评估的应用价值.方法:回顾分析11例侵袭性纤维瘤病的MRI表现及术中所见,并对4例大体病理标本进行组织大切片和特殊染色.结果:T1WI呈等信号5例,稍低信号6例,T2WI均呈稍高信号,内见星芒状、条索状低信号,增强后病灶明显强化.边界不清10例,边缘呈爪状生长;边缘清晰1例,可见假包膜.术中见7例与邻近血管粘连,4例累及邻近神经.结论:侵袭性纤维瘤病的MRI表现具有一定特征性,MRI可反映侵袭性纤维瘤病的组织学特点,并能显示肿瘤与邻近血管的关系,可作为诊断侵袭性纤维瘤病的首选方法.     

颞下窝原发肿瘤的CT及MR表现

目的：探讨颞下窝原发肿瘤CT及MRI表现。方法回顾性分析20例经病理证实的颞下窝原发肿瘤的CT及MR资料。结果颞下窝肿瘤形态多不规则。神经鞘瘤多边界清楚（5/6）,MR T1WI为等信号,T2WI为高信号肿物伴线状分隔样低信号,2例通过卵圆孔伸入中颅窝呈哑铃状生长。恶性外周神经鞘膜肿瘤边界多不清楚（4/5）,MR T1WI为等信号,T2WI为不均匀高信号,病变可侵犯邻近肌肉及骨质。横纹肌肉瘤MR T1WI为等信号,T2WI为高信号。孤立性纤维性肿瘤边界清楚,MR T1 WI等信号,T2 WI为混杂略高信号,增强后较明显强化。腺样囊性癌边界不清,沿神经浸润生长。侵袭性多形性腺瘤MR T1 WI为等、低信号,T2 WI为高信号,侵犯邻近肌肉。淋巴瘤形态不规则,边界清楚,MR T1WI为低信号,T2WI为中高信号,轻度强化,内有线样血管影穿行。结论熟悉颞下窝原发肿瘤CT及MRI表现,有助于提高该部位病变诊断及鉴别诊断水平。     

睾丸生殖细胞肿瘤的MRI诊断

目的：探讨睾丸生殖细胞肿瘤的 MRI 表现,提高对该疾病的 MRI 诊断水平。方法回顾性分析经手术病理证实的25例睾丸生殖细胞肿瘤患者临床及 MRI 资料,所有病例均行 MRI 平扫,其中16例行动态 MRI 增强扫描。利用 MRI 对睾丸肿瘤的大小、形态、信号特点、毗邻关系、强化方式及肿瘤血管情况进行评估,并与病理对照。结果25例睾丸生殖细胞肿瘤中,精原细胞瘤10例,其中 T2 WI 呈均匀低信号8例,稍低信号2例,增强扫描轻度结节样强化5例,明显均匀强化2例,其中4例可见纤维间隔强化;卵黄囊瘤4例,T1 WI 呈等低信号,T2 WI 呈稍高信号,增强扫描后肿瘤呈渐进式强化;成熟型畸胎瘤、表皮样囊肿、混合性生殖细胞肿瘤各3例,T1 WI 呈混杂低信号,T2 WI 呈混杂高信号;胚胎性癌2例,T1 WI 呈等低信号,T2 WI 呈混杂低信号,其内可见出血信号,增强扫描呈分隔强化。结论MRI 对睾丸生殖细胞肿瘤诊断正确率较高,对其病理分型、分期及鉴别诊断具有重要价值。     

韧带样纤维瘤病MRI特征表现及其病理基础

目的：探讨韧带样纤维瘤病（DF）的MRI特点,重点分析MRI特征影像及其病理基础,评价MRI在DF诊断中的价值。方法回顾性分析经手术病理证实14例韧带样纤维瘤病的MRI表现（14个病灶均行M RI增强及延迟扫描）,与术后病理结果进行比较,并探讨M RI特征影像的病理基础。结果14例均为单发病灶（腹外型7例、腹壁型4例、腹内型3例）,其中有2例为术后复发,肿瘤沿着肌肉长轴生长。T1 WI呈等或稍低于肌肉的信号,T2 WI呈高于肌肉信号,增强扫描病灶均呈不均匀强化,以延迟强化为明显,病灶内可见条状或带状 T1 WI及 T2 WI低信号,增强后未见强化。14例病灶内均未见坏死、囊变及瘤周水肿。病理组织学上肿瘤由不同比例的成纤维细胞、纤维组织和胶原纤维束组成,纤维细胞及成纤维细胞密集区域T2 WI信号增高,而肿瘤内胶原纤维区域在 T1 WI、T2 WI均为低信号。肿瘤内见较多血管壁完整的毛细血管,这是病灶延迟强化的病理基础。结论病灶内可见T1 WI、T2 WI均呈带状低信号且增强扫描不强化以及病灶延迟强化是DF的特征性MRI表现。MRI可以很好评估肿瘤侵犯范围及其与周围结构的关系,有助于DF的诊断和鉴别诊断。     

胚胎发育不良性神经上皮瘤的CT和MRI表现

目的:探讨胚胎发育不良性神经上皮瘤(DNET)的CT和MRI表现。方法:回顾性分析6例经手术病理证实的DNET的MRI和CT资料。6例均行常规MRI检查,其中4例行液体衰减翻转恢复(FLAIR)序列和扩散加权成像(DWI),3例行MR波谱检查。6例中5例行CT平扫。结果:6例中5例为单发,1例为弥漫性。病灶均位于或主要位于皮层区,单发者呈倒三角型表现。肿瘤以囊性成分为主,于CT平扫上均为低密度影,1例可见钙化;其MRI表现为T1WI低信号,T2WI高信号,FLAIR序列上病灶边缘和分隔呈高信号改变,增强扫描示病灶实质结节或分隔有轻度强化,病灶周围均未见水肿。结论:瘤周无水肿、倒三角征和瘤内分隔为PNET的特异性影像学表现,其影像学表现有助于临床诊断和治疗。     

Pituitary macroadenomas: preoperative evaluation of consistency with diffusion-weighted MR imaging--initial experience

PURPOSE: To prospectively evaluate use of diffusion-weighted (DW) magnetic resonance (MR) images and apparent diffusion coefficient (ADC) maps for determination of the consistency of macroadenomas. MATERIALS AND METHODS: The study protocol was approved by the institutional ethics committee, and informed consent was obtained from all patients. Twenty-two patients with pituitary macroadenoma (10 men, 12 women; mean age, 54 years +/- 17.09 [standard deviation]; range, 21-75 years) were examined. All patients underwent MR examination, which included T1-weighted spin-echo and T2-weighted turbo spin-echo DW imaging with ADC mapping and contrast material-enhanced T1-weighted spin-echo imaging. Regions of interest (ROIs) were drawn in the macroadenomas and in normal white matter on DW images, ADC maps, and conventional MR images. Consistency of macroadenomas was evaluated at surgery and was classified as soft, intermediate, or hard. Histologic examination was performed on surgical specimens of macroadenomas. Mean ADC values, signal intensity (SI) ratios of tumor to white matter within ROIs on conventional and DW MR images, and degree of enhancement were compared with tumor consistency and with percentage of collagen content at histologic examination by using analysis of variance for linear trend. RESULTS: The mean value of ADC in the soft group was (0.663 +/- 0.109) x 10(-3) mm(2)/sec; in the intermediate group, (0.842 +/- 0.081) x 10(-3) mm(2)/sec; and in the hard group, (1.363 +/- 0.259) x 10(-3) mm(2)/sec. Statistical analysis revealed a significant correlation between tumor consistency and ADC values, DW image SI ratios, T2-weighted image SI ratios, and percentage of collagen content (P < .001, analysis of variance). No other statistically significant correlations were found. CONCLUSION: Findings in this study suggest that DW MR images with ADC maps can provide information about the consistency of macroadenomas.     

可复性后部脑病综合征的MR诊断

目的 提高对可复性后部脑病综合征(PRES)的MRI诊断及鉴别诊断的认识.资料与方法 回顾性分析8例经临床证实的PRES患者的临床及MRI表现.8例均行MRI检查,其中3例行钆喷替酸葡甲胺(Gd-DTPA)增强扫描,2例行磁共振血管造影(3D-TOF MRA)检查,1例行增强磁共振静脉成像(CE-MRV)检查,6例行扩散加权成像(DWI).结果 MRI显示病灶基本上呈双侧对称性分布,6例位于顶、枕叶皮层及皮层下,2例累及脑干.T_1WI呈等或略低信号,T_2WI及液体衰减反转恢复(FLAIR)呈高信号,注射Gd-DTPA后无明显异常对比强化,MRA未见明显异常,DWI显示病变扩散受限呈高信号,ADC图呈高信号或为正常.7例经对症处理后多次复查示所有病灶几乎完全吸收消失,临床症状好转;1例因多系统衰竭死亡.结论 MRI对PRES的病变范围显示清楚,具有一定的特征性,多种MR检查方法并结合治疗后复查可以明确该病的诊断.     

侧脑室内脑膜瘤的CT和MRI诊断

目的分析侧脑室内脑膜瘤的CT和MRI表现,以提高诊断准确性。方法回顾性分析8例手术病理证实的侧脑室内脑膜瘤的CT和MRI资料。结果肿瘤呈圆形或分叶状软组织肿块,CT平扫多呈稍高或高密度,MRI多表现为T1WI等信号、T2WI等高信号,除1例因肿瘤坏死致信号和强化不均匀外,余7例肿瘤密度、信号及强化较均匀;周围脑组织可见不同程度水肿。1例肿瘤稍向周围脑组织呈浸润性生长,病理诊断为恶性脑膜瘤。结论侧脑室内脑膜瘤的CT、MRI表现具有一定的特征性,结合临床资料可提高诊断准确性。     

血管球瘤的临床及MRI诊断(附3例分析)

目的:探讨血管球瘤的MRI表现,以提高对其MRI表现的认识。方法:对3例手指血管球瘤的患者行MRI平扫和增强扫描,3例均经手术和病理证实。结果:肿瘤呈结节状,位于肌肉软组织内;在T1WI上为等或稍低信号,在T2WI及梯度回波序列上为高信号,静脉注射Gd-DTPA后病变明显强化。结论:MRI能明确血管球瘤的解剖部位,提示其组织学特点,对指导其手术治疗具有重要的临床价值。     

结节性硬化神经影像表现的再认识

分析结节性硬化的ＣＴ和ＭＲＩ影像表现特征。材料与方法，经临床诊断为结节性硬化患者中，２０例经ＣＴ检查，４例ＭＲＩ检查，其中２例既有ＣＴ又有ＭＲ检查。结果结节性硬化的影像表现主要征象有（１）皮层结节病灶，其表现有脑回核心样病灶，Ｈ型病灶。     

Basal cell adenoma of the parotid gland: MR imaging findings with pathologic correlation

BACKGROUND AND PURPOSE: Basal cell adenomas (BCAs) are rare tumors of the parotid gland. Only a few case reports describing MR imaging features of BCA have been published. The aim of this study was to describe and characterize the MR findings of BCAs of the parotid gland. MATERIALS AND METHODS: We retrospectively reviewed MR images of BCA with pathologic correlation in 8 cases (2 men and 6 women; age range, 52-82 years) collected between January 1992 and August 2004 from our pathologic data base. All MR images were retrospectively evaluated with respect to the marginal morphology, signal intensity (SI), and enhancement behavior by 2 experienced radiologists. RESULTS: On pathologic examination, 5 tumors were solid type, 2 were trabecular type, and 1 was membranous type. All of the tumors were well circumscribed with smooth contours. Cystic changes were seen in 4 cases. On T1-weighted images (T1WI), 7 tumors showed homogeneously low SI equal to muscle and one showed heterogeneously low SI. On T2-weighted images (T2WI), all of them showed slightly lower SI than that of surrounding parotid tissue. On gadolinium-enhanced T1WI, 6 tumors demonstrated moderate enhancement and one demonstrated strong enhancement (membranous type). Dynamic studies were performed in 4 cases. All showed rapid and prolonged enhancement. CONCLUSION: MR imaging findings of BCA were well-defined and smooth marginal morphologies, relatively low SI on both T11W and T2WI, and rapid and prolonged enhancement on dynamic study. Although BCAs are rare, they should be suspected when a tumor shows all of the characteristics noted here.     

Pituitary adenomas: early postoperative MR imaging after transsphenoidal resection.

BACKGROUND AND PURPOSE: Although there have been several reports on postoperative MR imaging of the sella, immediate postoperative changes (usually within 3 days) have not been extensively analyzed. The purpose of this study was to establish the value of early postoperative MR imaging in differentiating residual tumor from postoperative surgical changes in the sella after transsphenoidal resection of pituitary adenomas. METHODS: Eighty-three patients with surgically proven pituitary adenomas (32 nonfunctioning, 24 prolactin-secreting, 22 growth hormone-secreting, and five prolactin- and growth hormone-secreting tumors) were studied prospectively. All patients underwent dynamic MR imaging within 7 days after surgery. We analyzed the postoperative MR images by focusing on changes in the pituitary gland, signal intensity, resorption of implanted material, and visibility of residual tumor. The patients were divided into four groups according to enhancement pattern of the postoperative pituitary mass: no enhancement, nodular enhancement, peripheral rim enhancement, and a combination of nodular and peripheral rim enhancement. RESULTS: Postoperative changes included resorption of implanted material and reexpansion of the pituitary gland. In 22 patients, residual tumors were found, and all patients showed nodular or combined enhancement. The residual tumors were confirmed by immediate reoperation in three patients, by hormonal assay and follow-up MR images in 11 patients with functioning adenomas, and by growth of the tumor on follow-up MR images in eight patients with nonfunctioning adenomas. Forty-eight patients showed no enhancement and 13 patients showed peripheral rim enhancement. CONCLUSION: Early postoperative dynamic MR imaging after transsphenoidal resection in pituitary adenoma is very effective in differentiating residual tumor from postoperative surgical changes.     

中枢神经细胞瘤的CT与MRI诊断

目的:研究中枢神经细胞瘤(CNC)的CT与MRI影像特点,以提高对该病的认识。方法:回顾性分析经手术病理证实的CNC 5例,分析其临床CT与MRI表现。结果:本组病例中肿瘤均位于侧脑室透明隔,靠近Monro孔处,在CT上呈等或稍高密度,在MRI T1WI呈等或稍低信号,T2WI上呈不均匀高信号,增强后可见不均匀明显强化。肿瘤均可见囊变,边缘清晰。结论:青年人位于透明隔的肿瘤,应考虑CNC的诊断,CT与MRI有助于诊断此病,确定手术方案。