颅内原发恶性肿瘤柔脑膜转移的MRI诊断

目的：探讨颅内原发恶性肿瘤柔脑膜转移的MR影像学特征,为临床提供早期诊断和治疗依据。方法：搜集33例诊断颅内原发恶性肿瘤柔脑膜转移惠者的MR扫描资料,扫描选用常规自旋回波脉冲序列,10例加扫液体衰减反转恢复脉冲序列,全部病例均行增强扫描。结果：平扫表现为不同范围脑池、脑沟和／或脑室变形、移位,结构模糊,其中28例伴有明显脑回肿胀．合并脑室壁不均匀增厚8例;合并蛛网膜下腔肿瘤结节9例,共发现结节17个,合并脑积水10例,部分病例上述表现合并存在。其中10例另选用液体衰减反转恢复脉冲序列扫描后,转移病灶轮廓显示较常规SE序列清晰,信号略高于TSE—T2WI。瘤体边缘与周围水肿难于分辨。增强扫描后脑内瘤体均明显增强,柔脑膜转移显示呈不同强化特征,8例尾征,14例线征,6例条索征及9例环征或结节征,少部分病例合并两种征象存在。结论：加深对颅内原发恶性肿瘤柔脑膜转移的MR影像特征的认识,选择适当的MR成像技术,提高脑膜病变的早期检出率,对临床选择治疗方案具有十分重要的意义。     

鞍旁海绵状血管瘤与脑膜瘤的MR鉴别诊断

目的探讨鞍旁海绵状血管瘤与脑膜瘤的MR鉴别诊断要点。方法收集我院经手术病理证实的6例鞍旁海绵状血管瘤和15例鞍旁脑膜瘤的影像资料,比较两者MRI平扫及增强扫描表现的不同之处。结果鞍旁海绵状血管瘤以稍长T1、长T2为主要表现,DWI呈等信号,ADC值约为1.63×10-3 mm2/s,增强扫描3例早期明显均匀强化,3例延迟后均匀强化,邻近颞叶无水肿,颈内动脉海绵窦段包绕或被推压。鞍旁脑膜瘤表现为等T1、等T2信号常见,DWI呈等或略高信号,ADC值约为0.93×10-3 mm2/s,病变明显强化,12例可见"脑膜尾征"。结论鞍旁海绵状血管瘤T2WI呈明显高信号、ADC值高,脑膜瘤可见"脑膜尾征"。     

颅内血管周细胞瘤的影像学分析

目的探讨颅内血管周细胞瘤(hemangiopericytoma,HPC)的影像学表现,并复习相关文献,以提高诊断水平。资料与方法回顾性分析经手术病理证实的HPC2例。2例均行MR平扫和增强扫描。结果2例HPC分别位于右侧后颅窝和左侧颞部,均呈分叶状或不规则形,T2WI及T1WI均以等信号为主,增强扫描肿瘤实性部分明显强化。周围轻度水肿,占位效应不明显,1例肿瘤见流空血管信号及坏死、囊变区,1例增强后见脑膜尾征。结论HPC与脑膜瘤的MRI表现相似,影像表现有一定提示作用,确诊依赖病理。     

DWI及增强扫描对幕下原发淋巴瘤的应用价值

目的探讨MR扩散加权成像(DWI)及增强扫描在原发性小脑淋巴瘤中的诊断及鉴别诊断价值。方法对5例经临床手术病理证实的小脑淋巴瘤患者,行常规MR、DWI及增强扫描,回顾性分析各病例的平扫、DWI及增强扫描特征,并定量测定肿瘤实质区表观扩散系数(ADC)值;同时选取经手术病理证实的幕下实质型血管母细胞瘤4例,髓母细胞瘤8例,脑膜瘤10例进行DWI及增强扫描对比分析。结果 5例淋巴瘤,单发3例,多发2例,共计病灶数8个,T1WI呈等或稍低信号,T2WI以等或稍高信号为主,其中1例2个病灶表现为T_2WI低信号;DWI上2个病灶呈低信号,1个病灶为等信号,余病灶呈高信号表现,增强后,所有病灶均明显强化,1个病灶强化欠均质,余强化均匀,DWI与增强对照,测得肿瘤实质区的平均ADC值为(0.66±0.10)×10-3mm2/s,其中有3个病灶累及邻近脑膜,致脑膜增厚、强化;实质型血管母细胞瘤明显强化,DWI上呈低信号,实质区的平均ADC值为(1.93±0.13)×10-3mm2/s;髓母细胞瘤呈中-明显强化,DWI上呈高信号,实质区的平均ADC值为(0.71±0.11)×10~(-3)mm~2/s;脑膜瘤呈中-明显强化,6例出现脑膜尾征,DWI上5例为等信号,3例为稍低信号,2例为稍高信号,实质区的平均ADC值为(1.07±0.22)×10-3mm~2/s。淋巴瘤的ADC值最低,其次是髓母;强化程度上实质型血管母细胞瘤最高,其次是淋巴瘤。结论应用DWI结合增强扫描对幕下淋巴瘤的诊断及鉴别诊断有重要价值,能够明显提高淋巴瘤的诊断准确率。     

颅内孤立性纤维瘤的影像表现

目的 探讨颅内孤立性纤维瘤(ISFT)的影像特征.方法 回顾性分析经病理及免疫组织化学证实的10例ISFT患者的CT及MRI表现.所有患者均行MR平扫及增强扫描,其中4例行CT平扫.结果 所有病例术前均误诊为脑膜瘤,5例位于幕上、4例位于幕下、1例同时生长于幕上及幕下.所有病变均起源于颅内硬脑膜,8例肿瘤边缘可见明显分叶或浅分叶.4例CT检查均呈稍高密度,1例压迫颅底骨质致骨质吸收.仅1例可见包膜点样钙化,所有病灶实质内均未见钙化.T1WI以等、稍高信号为主,4例病灶信号均匀、6例信号不均.T2WI 2例病灶呈均匀等信号及低信号,4例表现为等、稍高或低信号相间,2例合并囊变,2例可见稍高T2信号及低T2信号两部分,呈所谓“阴阳征”.增强扫描所有病灶均明显强化,8例强化不均匀,低T2信号区域可见明显强化,4例出现“脑膜尾征”.结论 ISFT影像表现具有一定特点,当脑外肿瘤明显分叶,T2WI信号不均,存在低T2信号区域并明显强化,“脑膜尾征”较少或轻,无颅骨增厚等征象时有助诊断,典型“阴阳征”提示孤立性纤维瘤可能性大.     

颅内血管周细胞瘤与脑膜瘤的MRI鉴别诊断分析

目的探讨颅内血管周细胞瘤与脑膜瘤的MRI表现及诊断的价值。方法分析经病理证实的颅内血管周细胞瘤9例及脑膜瘤11例,均行MRI平扫和增强扫描。结果血管周细胞瘤一般形态不规则、少见脑膜尾征、邻近骨质溶骨性破坏、信号混杂、强化程度及时间较脑膜瘤长、内见流空血管、易复发及转移;脑膜瘤形态规则、常见脑膜尾征、邻近骨质增生硬化、信号较均匀。结论 MRI对颅内血管周细胞瘤与脑膜瘤的鉴别有较重要的价值。     

脑膜瘤的MRI征象及相关病理(附51例病例分析)

目的:分析脑膜瘤MRI表现及其相关病理.方法:回顾性分析51例经手术证实的脑膜瘤MRI图像,从其信号特点、肿瘤-脑组织界面、瘤周水肿、脑膜尾征病灶增强后MRI信号均匀度等方面进行归纳,并观察相关病理学资料.结果:脑膜瘤大多T1WI为等低信号,T2WI以稍高信号和混杂信号多见,脑膜尾征具有诊断价值.结论:脑膜瘤MRI征象有较高的敏感性和特征性,大多数能在术前诊断,为手术方式提供帮助.     

鞍内脑膜瘤的MRI诊断与鉴别诊断

目的探讨鞍内脑膜瘤的MRI的影像特点。资料与方法回顾性分析5例经手术和病理证实的鞍内脑膜瘤的MRI表现。结果5例均位于鞍内,其中起源于鞍结节4例,鞍隔1例。5例均呈均匀明显强化。3例垂体可见．2例未见垂体。脑膜尾征4例,尾征不明显1例。5例颈内动脉均受推压移位。结论增强扫描明显均匀强化．且垂体可见,并出现脑膜尾征以及颈内动脉受推压为鞍内脑膜瘤的特征。     

“硬脑膜尾征”:脑膜瘤的特异性MR征象?

作者为了确定“硬脑膜尾征”——即在Gd-DTPA增强MR的T_1加权象上邻近颅内肿块周围的硬脑膜线样增厚和强化,对脑膜瘤的特异性,回顾了16例具有尾征的病例。13例组织学诊断为脑膜瘤,其它3例为绿色瘤、淋巴瘤和类肉瘤病。其中15例作了病理与MR表现的对照研究。所有的“尾征”均为邻近肿块处最厚,然后逐渐变细。作者回顾,New等于1982年首先描述了在增强CT检查中,恶性脑膜瘤肿块向周围延伸的肿瘤血管翳,称之为“蘑菇样”蕈征,认为在良性脑膜瘤中不存在此表现。Wilms等于1989年首次报道增强MR图象上的     

恶性脑膜瘤的CT与MRI诊断和鉴别诊断

目的分析恶性脑膜瘤的CT与MRI影像学特征,以提高其定性诊断的正确性。方法回顾性分析经手术与病理证实的9例恶性脑膜瘤的CT与MRI影像学表现,并结合文献进行复习。结果9例恶性脑膜瘤全部发生于脑外,增强后均有明显强化,CT清晰显示肿瘤内钙化、骨质破坏,MR可三维成像,清晰显示肿瘤内囊变、脑膜尾征。结论CT与MRI相辅相成,为恶性脑膜瘤的诊断和鉴别诊断提供重要的信息,结合病人临床资料可进一步提高诊断准确率。     

“Dural tail” adjacent to a giant posterior cerebral artery aneurysm: case report and review of the literature

The “dural tail” sign on gadolinium (Gd-DTPA)-enhanced MRI has been described in association with meningiomas. Various series with histopathological correlation have shown that in some cases there is tumour invasion into the dura mater, but in the majority of cases it represents a hypervascular, non-neoplastic reaction. While this sign was originally thought to be specific for meningioma, subsequent case reports have described the presence of a dural tail in other intra- and extra-axial lesions. We present a patient with a giant aneurysm arising from the P2 segment of the right posterior cerebral artery, adjacent to the tentorium, with a prominent dural tail on Gd-DTPA-enhanced MRI. In this location, differentiation of an aneurysm from a meningioma was critical. Received: 24 September 1996 Accepted: 7 October 1996     

Dural invasion of meningiomas adjacent to the tumor margin on Gd-DTPA-enhanced MR images: histopathologic correlation

In intracranial meningiomas a flat, contrast-enhancing, dural structure adjacent to the tumor can occasionally be observed on gadolinium-DTPA-enhanced MR images. We wished to evaluate whether there is a correlation between MR images and meningeal invasion of intracranial meningiomas. The study included 54 patients with intracranial meningioma and the meningeal sign. MR studies included T2-weighted and gadolinium-DTPA-enhanced T1-weighted images in axial, coronal, and sagittal planes. Histopathologic examinations were done on the meningiomas adjacent to the dura mater. The meningeal sign on MRI was observed from 2 up to 35 mm from the main tumor mass in 31 (57 %) of the 54 patients. In 20 of these 31 the histopathologic examination showed tumor invasion, while 11 patients had no tumor invasion but tissue proliferation, hypervascularity, and vascular dilatation. Seven of the 23 meningiomas without the meningeal sign had histologically proven infiltration of the adjacent dura. MR imaging is not able to determine definitive whether or not there is dural infiltration of the meningiomas. In conclusion, resection of the tumor with a wide margin is necessary to achieve complete excision of meningioma and to avoid recurrence. Received 23 July 1997; Revision received 10 October 1997; Accepted 17 October 1997     

鞍结节脑膜瘤与向前上生长的垂体腺瘤MRI鉴别诊断

目的 探讨鞍结节脑膜瘤与向前上生长的垂体大腺瘤的影像学鉴别要点。资料与方法 分析17例经手术证实的鞍结节脑膜瘤的MRI征象,并与同期病理确诊的14例垂体大腺瘤进行对照。结果 17例脑膜瘤：均显著强化,包绕颈内动脉13例,长脑膜尾征14例、瘤周较多流空信号5例,蝶鞍扩大9例,垂体柄不能辨认11例,肿块与垂体分界不清7例,无腰征。14例垂体大腺瘤：7例显著强化、但不均匀,颈内动脉包绕14例,短脑膜尾征9例,较多流空信号2例,蝶鞍扩大14例,垂体柄不能辨认14例,见不到垂体结构13例,腰征12例。鞍结节脑膜瘤的瘤体显著及均匀强化、脑膜尾征粗大、瘤内星状改变均明显不同于垂体大腺瘤,其中长脑膜尾征、明显及均匀强化价值最大。结论 长脑膜尾征和肿瘤明显及均匀强化、无腰征是鞍结节脑膜瘤的特征性表现,对于鉴别鞍结节脑膜瘤与向前上生长的垂体大腺瘤具有重要价值。     

“Dural tail” adjacent to acoustic neuroma on MRI: a case report

A dural tail on Gd-DTPA-enhanced MRI has been often observed adjacent to meningiomas and considered to be useful in distinguishing meningioma of the cerebellopontine angle from acoustic neuroma. However, demonstration of a dural tail adjacent to an acoustic neuroma indicates that this sign is not specific.     

Dural congestion accompanying meningioma invasion into vessels: the dural tail sign

Our purpose was to verify the histological appearance of the dural tail accompanying meningiomas on MRI. We studied seven patients such a dural tale. We examined the point of attachment of the tumour and the adjacent dura mater histologically. In all patients, rich vascularity and dilated vessels were observed in the dura mater at the point of attachment of the tumour; tumour cells invaded the dura mater and vessels, packing the latter. In the adjacent dura mater, showing as a dural tail on MRI, there was tumour-cell invasion in only one patient. Vascular congestion around the vessels compacted by the tumour cells in the dura mater and dilated vessels were seen in all patients. We therefore suggest that the mechanism of the dural tail sign is as follows. First, tumour cells invade vessels and pack them at the point of tumour attachment. Then, vessel congestion is induced in the adjacent dura mater, as a result of which it enhances markedly, giving rise to the dural tail sign. Received: 31 July 2000 Accepted: 29 September 2000     

Dural tail sign in spinal meningiomas

OBJECTIVE: To study the association between the "dural tail sign" and spinal meningiomas on MR imaging. METHODS: Retrospective review of MR examinations of all pathologically proven spinal meningiomas from 1998 to 2005 was performed. Lesions were evaluated for size, signal intensity, enhancement pattern, and presence or absence of dural tail. The dural tail length and direction in reference to the meningioma were also evaluated. RESULTS: Seven spinal meningiomas were identified in seven patients. One lesion was purely extradural, while the remaining were intradural extramedullary. Dural tail was present in four cases (57%) and its length ranged between 5 and 21 mm. The tail was seen cranial and caudal to the meningioma in three cases and only cranially in one. Coronal images were available in three cases and in two of these; the dural tail was clearly depicted. CONCLUSIONS: "Dural tail sign" is as common in spinal meningiomas as in cranial meningiomas.     

Contrast-enhanced MR images in patients with meningioma: importance of enhancement of the dura adjacent to the tumor

Linear enhancement (flare sign) along the dura mater that was continuous with or emanated from the dural margin of meningiomas was frequently observed on contrast-enhanced MR images obtained in 18 patients with intracranial meningiomas (surgically proved). Preoperative MR studies obtained at 1.5 T after administration of gadopentetate dimeglumine were reviewed retrospectively to determine the clinical significance of this sign. Thirteen (72%) of the 18 meningiomas exhibited the finding adjacent to the dural attachments. Four meningiomas of the cerebellopontine angle showed enhancement along the internal auditory canals. Three specimens of the dura adjacent to the tumor in different patients with this finding revealed proliferation of connective tissues abounding with vessels along the dura without definite tumor invasion. The flare sign is thought to be a common finding of meningiomas on contrast-enhanced MR images obtained with high-resolution sequences, and it is observable without tumor invasion. This sign in the cerebellopontine angle should not be misinterpreted as enhancement of acoustic schwannomas.     

椎管内脊膜瘤及神经源性肿瘤MRI增强影像的特征性分析

目的:分析椎管内脊膜瘤及神经源性肿瘤MR增强影像的特征。方法:搜集经手术病理证实的椎管内脊膜瘤11 例,神经源性肿瘤12例,全部病例均行MR平扫及增强扫描。结果:椎管内脊膜瘤MR增强影像特征为“肿瘤周边重度环状增强”、脊膜“尾巴征”;神经鞘瘤MR增强影像特征为多灶样不增强;神经纤维瘤MR增强影像特征为病灶内星芒状不增强。结论:椎管内脊膜瘤及神经源性肿瘤都有各自的MR增强影像特征,其对定性诊断有重要价值     

Dural tail sign in spinal meningiomas

ObjectiveTo study the association between the “dural tail sign” and spinal meningiomas on MR imaging.MethodsRetrospective review of MR examinations of all pathologically proven spinal meningiomas from 1998 to 2005 was performed. Lesions were evaluated for size, signal intensity, enhancement pattern, and presence or absence of dural tail. The dural tail length and direction in reference to the meningioma were also evaluated.ResultsSeven spinal meningiomas were identified in seven patients. One lesion was purely extradural, while the remaining were intradural extramedullary. Dural tail was present in four cases (57%) and its length ranged between 5 and 21 mm. The tail was seen cranial and caudal to the meningioma in three cases and only cranially in one. Coronal images were available in three cases and in two of these; the dural tail was clearly depicted.Conclusions“Dural tail sign” is as common in spinal meningiomas as in cranial meningiomas.