颅内巨大动脉瘤的CT与MR诊断

目的：探讨ＣＴ和ＭＲ对颅内巨大动脉瘤的诊断价值。方法：８ 例颅内巨大动脉瘤病人进行了ＣＴ和ＭＲ检查,并经血管造影和手术证实。其中,男４ 例,女４ 例,年龄３４～７２岁,平均５４岁。临床上５例表现为颅内占位症状,３例为蛛网膜下腔出血症状。结果：５例动脉瘤起源于颈内动脉,２ 例起源于大脑中动脉,１例起源于椎基底动脉。ＣＴ和ＭＲ表现如下：（１）ＣＴ平扫病灶呈稍高密度圆形阴影,密度可均匀或不均匀,增强扫描病灶明显强化。（２）ＭＲ扫描显示残存瘤腔在Ｔ１ＷＩ及Ｔ２ＷＩ上均呈无信号区,周围为混合信号带。该信号带在Ｔ１ＷＩ上信号稍高于脑灰质,在Ｔ２ＷＩ上则稍低于脑灰质。增强扫描部分病例动脉瘤壁及混合信号带有强化表现。（３）动脉瘤破裂时,ＣＴ与ＭＲ可显示相应出血表现。结论：对颅内巨大动脉瘤的诊断,ＭＲ优于ＣＴ,尤其在显示瘤腔和血栓方面ＭＲ有独到之处     

脊髓室管膜下瘤的MR影像诊断

目的 研究脊髓内室管膜下瘤的MRI特征。方法 4例脊髓室管膜下瘤均行MR检查并经手术病理证实，均为男性，年龄15—47岁，平均36．3岁。回顾性分析脊髓内室管膜下瘤的MRI表现，结合术中所见总结MRI诊断与鉴别诊断要点。结果 4例脊髓内室管膜下瘤分别位于C3～T3、C2～6、T6～12、C1—T2段脊髓，肿瘤均位于脊髓腹侧，呈偏中心性生长。1例有轻度脊髓空洞。MR T1WI为等或低信号，信号不均，内有更低信号；T2WI为高信号。2例伴有小出血灶。增强扫描，3例肿瘤无强化或强化轻微，1例强化明显。结论 MRI可以很好评价脊髓内室管膜下瘤，当患者具备上述特点时高度提示脊髓内室管膜下瘤的可能。     

Intracranial tuberculoma: MR imaging

Summary MR studies of 6 patients with intracranial tuberculoma are reviewed. All patients also underwent CT scans which showed hypo- or isodense lesions with abnormal enhancement following contrast administration. MR showed lesions with prolongation of the T1 relaxation time in every case. On the T2-weighted sequences, the signal properties of the tuberculoma varied according to the stage of evolution of the lesion. Incipient tuberculomas appeared as scattered areas of hypointensity surrounded by edema. Mature tuberculomas were composed of a dark necrotic center surrounded by an isointense capsule which was, in turn, surrounded by edema. In one patient, the center of the lesion was hyperintense probably because of liquefaction and pus formation (tuberculous abscess). While both, CT and MR, were equally sensitive in visualizing the intracranial tuberculoma in every patient, MR was slightly superior in demonstrating the extent of the lesion, especially for brainstem tuberculomas. Nevertheless, the potential role for MR diagnosis of intracranial tuberculoma is limited by the fact that other infectious or neoplasic diseases may present similar findings. The diagnosis of intracranial tuberculoma should rest on a proper integration of data from clinical manifestations, cerebrospinal fluid analysis, and neuroimaging studies.Presented at the 23th Latinoamerican Congress of Neurosurgery, Acapulco, Mexico, 13–19 November 1988     

Intracranial aneurysms: MR imaging

Summary MR studies of 17 patients with 19 intracranial aneurysms are reviewed. All patients also underwent CT and angiography. MR has been able to visualize the aneurysms in all cases. Aneurysms present various MR appearances because of flow characteristics, thrombosis in different stages of organization, calcific and ferric deposits. Based on MR signal changes it is possible to distinguish between flow effects and histopathological components such as thrombosis. Flow patterns are complex and sometimes it is difficult to define the cause responsible for intraluminal signal. MR allows a precise definition of perilesional brain tissue and demonstrates associated lesions. Angiography remains the definitive procedure in the diagnosis of small aneurysms, but shows only that part of the lesion in continuity with the circulation. MR clearly delineates the size, the residual lumen and the extraaxial location of giant aneurysms. In completely thrombosed aneurysms, when CT suggest a tumor, MR is able to demonstrate the vascular nature of the lesion.     

Intracranial hemangioblastomas: CT and MR findings

The CT and magnetic resonance (MR) findings in eight patients with 10 biopsy-proven intracranial hemangioblastomas were reviewed. Three of these patients had von Hippel-Lindau (VHL) syndrome. Nine tumors were infratentorial, seven were cystic, and five had well-defined mural nodules. The only three solid tumors, the only brain stem tumor, and the only supratentorial tumor in this series occurred in VHL patients. Magnetic resonance detected a single tumor missed by CT, and no lesion seen on CT was missed by MR. The tumor nodule, when present, was identified in every case using MR, although it was usually more apparent on contrast-enhanced CT. In three cases MR was better than CT in defining the margins of posterior fossa tumors. Serpentine vessels were well seen as flow voids against high signal cyst or tumor on T2-weighted images, but contrast-enhanced CT also demonstrated them. Magnetic resonance was found superior to CT for the detection of intracranial hemangioblastomas, and complementary in their characterization.     

Rhinocerebral mucormycosis: MR manifestations

Magnetic resonance (MR) examinations of three patients with rhinocerebral mucormycosis are reviewed. The clinical course is outlined and the MR characteristics are analyzed in light of the known pathology. The major MR findings include sinus and orbital disease followed by deep facial extension. Involvement of basal portions of the hemispheres, brain stem, and hypothalamus occurred rapidly following ipsilateral facial or orbital invasion in all three cases. Regions of intracerebral inflammation were hyperintense compared with normal parenchyma on T2-weighted and proton density-weighted images. Septic cavernous sinus and internal carotid artery thrombosis was diagnosed by MR in one case. Magnetic resonance demonstrated partial resolution of intracerebral abnormalities that accompanied clinical improvement in the one surviving patient.     

幕上脑实质内室管膜瘤的MRI诊断

<正> 室管膜瘤是室管膜起源中最常见的肿瘤,大部分位于脑室内,位于幕上脑实质内的室管膜瘤由于其部位、信号特点缺少特征性而易误诊。现回顾性分析我院2000年2月～2010年4月28例幕上脑实质内室管膜瘤的MRI表现,以提高该病的影像诊断水平。1 资料与方法1.1 一般资料本组28例,男17例,女11例;年     

Intracranial vascular malformations: MR and CT imaging

Twenty-four patients with 29 cerebrovascular malformations were evaluated with a combination of computed tomography (CT), angiography, and magnetic resonance (MR) imaging. Characteristics of the malformations on MR images were reviewed retrospectively, and a comparative evaluation of MR and CT images was made. Of 14 angiographically evident malformations, 13 intra-axial lesions were detected on both CT and MR images, and one dural malformation gave false-negative results on both modalities. The appearance of parenchymal lesions on MR images closely mirrored characteristic CT findings. Calcific foci were difficult to separate from vessels on both images. Clot was more easily identified on MR images. In the detection of 15 angiographically occult malformations, CT proved more sensitive when focal calcification was the only evidence of their presence. MR study failed to detect two small supratentorial lesions evidenced by faint calcifications on CT scans. In two patients, MR images showed small hemorrhages not detectable by CT, and MR provided strong evidence for the diagnosis of hematoma for 12 lesions. Angiographically evident malformations have a highly characteristic appearance on MR images. MR may be more sensitive than CT in the detection of small hemorrhagic foci associated with cryptic arteriovenous malformations and may add specificity in the diagnosis of occult malformations in some cases, but MR is less sensitive than CT for the detection of small calcified malformations.     

幕上脑实质室管膜瘤CT和MR诊断

目的：分析幕上脑实质室管膜瘤ＣＴ和ＭＲ影像学特点。材料与方法：２４例经手术病理证实的幕上脑实质室管膜瘤，行ＣＴ和（或）ＭＲ检查；男１６例，女８例；１０岁以下９例，１１～２０岁６例，２０岁以上９例。结果：部分囊性型２１例，好发于顶叶，肿瘤部分为囊性，实质较少，囊液在ＣＴ平扫时稍高于脑脊液密度，ＭＲＴ１加权像信号稍高于脑脊液，Ｔ２加权像似脑脊液高信号。肿瘤实质在ＣＴ平扫时呈稍高密度或等密度，ＭＲＴ１加权像信号稍低于脑实质，ＭＲＴ２加权像似灰质信号或稍高于灰质信号。实质内常有条状或点状钙化。瘤周一般无水肿或仅有轻度水肿，增强扫描肿瘤实质及囊壁轻到中度强化。完全实质型多见于年长的成人，肿瘤好发于额叶，且常累及双侧，ＣＴ平扫时肿瘤多呈稍高密度，出血和钙化多见，瘤周水肿明显，多呈显著不均质强化。结论：幕上脑实质室管膜瘤可分为部分囊性型和完全实质型，部分囊性型ＣＴ和ＭＲ表现很有特点，常能提供准确诊断，完全实质型与胶质瘤鉴别困难。     

脑实质内室管膜瘤的MR诊断与鉴别诊断

目的:分析脑实质内室管膜瘤的MRI表现,旨在提高对其诊断的准确率。方法:对经手术病理证实的12例脑实质内室管膜瘤进行回顾性分析,均行颅脑MR平扫及增强扫描检查。结果:肿瘤10例位于幕上,其中5例位于丘脑,2例位于额叶(其中1例通过胼胝体累及双侧额叶),1例位于颞叶,1例位于额颞叶,1例位于颞枕交界区;幕下脑实质内室管膜瘤2例,1例位于小脑半球,1例位于小脑蚓部。10例肿瘤与脑室关系密切。7例肿瘤表现为实质型,T1WI呈低信号,T2WI呈高信号,其中2例病灶内有出血灶,4例可见多发小液化囊变区;5例表现为囊实性型,囊性部分T1WI呈低信号,T2WI呈明亮的高信号,信号与脑脊液信号相似,T2FLAIR像上呈低信号;实性部分T1WI呈等或略低信号,T2WI呈略高信号。增强扫描瘤体呈明显不均匀强化。结论:脑实质内室管膜瘤多发生于幕上,且多见于侧脑室三角区周围,与脑室关系密切,多呈实性,周围水肿多不明显。MRI表现有一定的特点,但多数情况下术前明确诊断困难。     

颅内恶性淋巴瘤的CT及MR诊断

颅内恶性淋巴瘤少见，容易误诊。作者总结了１８例手术后病理证实为恶性淋巴瘤的病例，其ＣＴ、ＭＲ表现有如下特点：（１）ＣＴ上平扫为类圆形、椭圆形或不规则形稍高密度影，不规则形多见，且边界不清楚，周围水肿较轻，占位征象相对小；（２）注药后病灶明显强化；（３）ＭＲ表现为长Ｔ１、长Ｔ２信号，注药后病灶也明显强化；（４）在ＭＲ Ｔ２ＷＩ上可发现沿室管膜的种植病灶，优于ＣＴ。作者根据ＣＴ、ＭＲ表现提出诊断与鉴别     

Intracranial hemangiopericytomas: MR and CT features.

PURPOSETo describe the MR and CT imaging features of hemangiopericytoma and to identify the characteristics that might distinguish them from meningioma.METHODSWe retrospectively reviewed the CT and MR findings in 34 pathologically proved cases of hemangiopericytoma. We evaluated the size, shape, and location of the tumor; the presence of hydrocephalus, edema, and mass effect; the type of dural attachment (broad-based or narrow-based) and bone changes (erosion, hyperostosis); and the tumor''s density, signal, and contrast-enhancement characteristics.RESULTSThirty of 34 tumors were 4 cm or more in greatest dimension, 32 were lobular, and only seven were in the posterior fossa. Hydrocephalus was present in 18, edema in 30, and mass effect in 33. Twenty-three had broad-based dural attachment and 11 had narrow-based attachment. All 26 unenhanced CT scans showed hyperdense tumors; 19 were heterogeneous and seven homogeneous. All 27 contrast-enhanced CT scans showed enhancement; 17 were heterogeneous and 10 homogeneous. Bone erosion was present in 17 of 29 hemangiopericytomas imaged with CT. None had hyperostosis or tumor calcifications. On T1-weighted MR images, 13 of 17 tumors were isointense with cortical gray matter; on T2-weighted image, 10 of 17 were isointense. All 14 tumors imaged with contrast enhanced T1-weighted MR imaging showed enhancement, and 13 of these were heterogeneous; eight of the 14 had a "dural tail" sign.CONCLUSIONIntracranial hemangiopericytomas are multilobulated, extraaxial tumors, sometimes associated with narrow-based dural attachment and bone erosion. Unlike with meningiomas, hyperostosis and intratumoral calcification are not present.     

Intracranial amebic abscesses: CT and MR findings

The CT and magnetic resonance findings in a case of intracranial amebic abscesses are described. Due to increased travel to endemic areas, amebic abscess should also be included in the differential diagnosis for patients who live in the temperate parts of the world.     

颅内结核的MRI表现及其分型

目的探讨颅内结核的MRI表现及分型。方法收集经手术病理或临床证实为结核的17例病例,观察其MR影像表现。结果MRI表现分为单纯颅内结核瘤5例,单纯结核性脑膜炎3例,颅内结核瘤并结核性脑膜炎9例。颅内结核瘤分成熟型结核瘤9例及非成熟型结核瘤5例。增强扫描可更明确显示小病灶。结核性脑膜炎表现为脑底池或脑沟内脑膜增厚,呈放射状或铸形样强化12例。结论MRI平扫及增强能明确显示颅内结核病变,并明确分型。     

颅内脑室外室管膜瘤的MRI诊断

目的 探讨颅内脑室外室管膜瘤的MRI表现.方法 结合10例经手术证实的颅内脑室外室管膜瘤,回顾性分析其MRI表现.结果 10例颅内脑室外室管膜瘤,其中室管膜瘤5例,间变性室管膜瘤5例,共10个病灶,枕叶3例,颞叶2例,额叶2例,跨叶生长3例,肿瘤均位于脑皮质区.肿瘤实质T1呈等或稍低信号,T2呈等或稍高信号,FLAIR呈等或稍高信号,肿瘤内部见多发囊变、坏死区;本组病例室管膜瘤5例均以实质性为主,间变性室管膜瘤5例均以囊性为主,其中2例室管膜瘤内可见长T1短T2钙化灶,1例间变性室管膜瘤内见出血;增强后肿瘤实质明显强化,囊变、坏死或钙化区不强化,囊壁可见环状强化.结论 进行颅内脑室外室管膜瘤的MRI表现研究,有助于本疾病诊断及鉴别诊断.