脉络丛肿瘤的影像学诊断及鉴别诊断

目的:研究脉络丛肿瘤的影像学表现,探讨其诊断与鉴别诊断.方法:搜集39例经手术病理证实的脉络丛肿瘤,其中脉络丛乳头状瘤35例,脉络丛癌4例.男性13例,女性26例,年龄1～ 60岁,平均19.5岁.所有病例均行CT和(或)MRI扫描.分析CT和MRI表现.结果:脉络丛肿瘤发生于侧脑室26例,9例位于第四脑室,3例位于桥...     

桥小脑角区脉络丛乳头状瘤影像学表现(附5例分析)

目的 探讨桥小脑角区(cerebellopontine angle,CPA)脉络丛乳头状瘤(choroid plexus papilloma,CPP)的影像学特点.资料与方法 搜集5例经手术病理证实的桥小脑角区脉络丛乳头状瘤(CPA-CPP),回顾性分析其CT及MRI表现,总结其影像学特点.结果 5例病灶均为单侧,边界清晰,呈分叶状.CT上呈与周围脑实质等密度或略低密度改变,2例病灶内可见钙化.MR T1 WI上病灶呈低信号或等信号,T2WI上呈混杂信号,4例病灶可见特征性血管流空信号.增强扫描所有病灶均呈明显较均匀强化.病灶不伴瘤周水肿,可由占位效应引起梗阻性脑积水.结论 CPA发生的CPP与其他部位发生的CPP影像学特征类似.发现分叶状形态、明显强化、血管流空信号对诊断有一定帮助.影像学检查对于CPA-CPP诊断具有重要价值.     

颅内髓上皮瘤的影像学表现

目的 总结颅内髓上皮瘤的影像学表现特点.资料与方法 分析1例婴儿原发性侧脑室内髓上皮瘤的MRI表现及病理资料,结合文献,对这一罕见疾病的CT及MRI表现、组织病理学表现及临床诊断等进行探讨.结果 MRI示肿瘤位于左侧侧脑室内,体积较大且不规则,信号亦不均匀,增强扫描实性部分明显强化,病理学表现支持髓上皮瘤的诊断,部分呈脉络丛乳头状瘤改变.结论 该病例为罕见的原发性侧脑室内髓上皮瘤,其影像学表现具有多样性,要在术前明确该病的诊断存在一定困难,最终确诊离不开病理及免疫组化结果等.     

脉络丛肿瘤的影像学征象与病理对照分析

目的：探讨脉络丛肿瘤（CPTs）的CT和 MRI表现特征,提高影像诊断的准确性。方法：回顾性分析28例经病理证实的CPTs患者的影像学资料,其中脉络丛乳头状瘤（CPP）22例,非典型性脉络丛乳头状瘤（ACPP）2例,脉络丛癌（CPC）4例。全部病例均行CT平扫、MRI平扫及增强扫描。结果：28例CPTs患者中男16例,女12例,年龄5个月～66岁,中位年龄30岁。发病部位包括侧脑室（12例）、第四脑室（8例）、桥脑小脑角区（6例）、三脑室（1例）和小脑蚓部（1例）。CPPs CT平扫多表现为较均匀等密度或稍高密度,其中6例伴有钙化;肿瘤实性部分在T1 WI 上呈等或稍低信号, T2 WI上呈等或稍高信号;MRI 增强扫描示肿瘤实性部分及囊壁呈明显强化。CPPs 内可见肿瘤血管,出血和囊变少见;APCCs更易发生囊变,可侵犯周围脑实质,易出现瘤周水肿;CPCs 可见瘤内出血、囊变、脑实质浸润、沿脑脊液播散等改变。结论：脉络丛肿瘤的CT和 MRI表现具有一定的特征性,MRI 能清晰显示肿瘤的形态学改变,为手术方案的制定及预后判断提供可靠的依据。     

侧脑室肿瘤的CT、MR诊断

目的 分析侧脑室肿瘤的CT与MRI影像学特征,提高对侧脑室各种肿瘤的诊断准确性。资料与方法 回顾性分析25例经手术与病理证实的侧脑室肿瘤的CT与MRI表现,其中CT检查5例,MRI检查7例,13例同时行CT和MRI检查。结果 25例中,脑膜瘤6例,室管膜瘤5例,星形细胞瘤4例,转移瘤3例,脉络丛乳头状瘤、中央性神经细胞瘤、室管膜囊肿各2例,室管膜下巨细胞瘤1例。CT显示肿瘤钙化较佳,MR定位准确性高,可以准确显示肿瘤的位置及邻近情况。结论 不同种类的侧脑室肿瘤与发病部位、患者年龄有一定的关系,结合发生部位和年龄特征,可提高诊断率。     

脑室内胶质瘤的MRI诊断

目的 分析脑室内胶质瘤的MRI特点,提高诊断准确性.资料与方法 经手术病理证实的脑室内胶质瘤29例,其中20例位于侧脑室,2例位于三脑室,7例位于四脑室.29例均行MR平扫及增强扫描.结果 (1)大多数脑室内胶质瘤如室管膜瘤、星形细胞瘤、脉络丛乳头状瘤等具有特征性的MRI表现;(2)部分肿瘤具有其好发部位,如脉络丛乳头状瘤好发于侧脑室三角区,室管膜瘤好发于侧脑室体部,髓母细胞瘤好发于四脑室区;(3)某些肿瘤具有年龄和性别特征,如星形细胞瘤患者年龄均＜30岁,脉络丛乳头状瘤患者年龄均＞50岁,室管膜瘤女性占66.67%.结论 脑室内胶质瘤有比较特征性的MRI表现,结合患者临床和发病年龄、性别、部位等特点,可进一步提高其术前诊断准确性.     

儿童侧脑室肿瘤的CT和MRI诊断

目的 分析儿童侧脑室肿瘤的CT与MRI影像学特征.方法 回顾性分析26例经手术与病理证实的儿童侧脑室肿瘤的CT与MRI表现,其中5例CT检查,7例MRI检查,14例同时做CT和MRI.结果 26例肿瘤包括脉络丛乳头状瘤10例,室管膜肿瘤7例,室管膜囊肿4例,室管膜下巨细胞星形细胞瘤2例,表皮样囊肿、脑膜瘤、恶性生殖细胞瘤各1例.儿童侧脑室肿瘤具有一定的CT、MRI特征性表现.结论 CT与MRI相结合,能为儿童侧脑室肿瘤的诊断和鉴别诊断提供更全面的信息,有助于提高术前诊断率.     

小脑肿瘤的CT与MRI鉴别诊断

目的:分析小脑肿瘤CT与MRI影像学特征,探讨其鉴别要点。方法:回顾性分析58例经手术与病理证实的小脑半球肿瘤的CT与MRI影像学表现。其中男性32例,女性26例;年龄7～61岁,平均年龄34岁。结果:58例中血管母细胞瘤26例,星形细胞瘤15例,髓母细胞瘤4例,室管膜瘤4例,表皮样囊肿2例,蛛网膜囊肿3例,脉络丛乳头状瘤1例,转移瘤3例。CT与MRI对小脑肿瘤的定位诊断准确率均为100%,在鉴别诊断中,尤其是囊性病变,MRI优于CT。结论:CT与MRI在小脑肿瘤的鉴别诊断中,二者相辅相成具有重要价值。     

胰腺实性-假乳头状瘤的影像学特征及误诊分析

目的探讨胰腺实性-假乳头状瘤的影像学特征,并对误诊病例进行分析,以期提高诊断准确性。方法选取经病理证实的胰腺实性-假乳头状瘤8例的临床及影像资料,8例均行CT平扫及增强检查,3例行MRI平扫及增强检查。结果 5例表现为囊实性肿物,边界清晰,实性成份轻至中度强化,囊性部分无强化,包膜多完整,明显强化。2例病灶以实性为主,1例病灶以囊性为主。诊断正确6例,1例误诊为胰头癌,1例误诊为腹膜后肿物,误诊率为25%(2/8)。结论胰腺实性-假乳头状瘤有一定的影像特点,但仍需注意其不典型表现,降低误诊率。     

四脑室区肿瘤的CT和MRI诊断

目的探讨四脑室区肿瘤的CT和MRI诊断价值.材料和方法分析31例经手术、病理证实的四脑室区肿瘤的CT和MRI好发年龄、部位和图像特征.结果检出髓母细胞瘤9例,室管膜瘤8例,表皮样囊肿4例,脉络丛乳头状瘤3例,血管母细胞瘤2例,室管膜囊肿1例,海绵状血管瘤1例,生殖细胞瘤1例.结果提示(1)不同的四脑室区肿瘤各具其影像学特征;(2)四脑室区常见肿瘤具有年龄特征;(3)肿瘤来源的判断可帮助肿瘤定性的诊断.结论CT和MRI检查对四脑室区肿瘤的诊断和鉴别诊断有主要价值,以MRI为首选方法.     

脉络丛乳头状瘤的MR,CT诊断

目的：分析脉络丛乳头状瘤的ＭＲＩ和ＣＴ表现。材料与方法：搜集经手术病理证实的脉络丛乳头状瘤２０例。全部病例均行ＭＲ或ＣＴ扫描。结果：脉络丛乳头状瘤在影像学检查中最大特点是肿瘤的位置和形态，肿瘤多位于扩大的脑室内，边缘凹凸不平，呈颗粒状。脉络丛乳头状瘤在ＭＲＴ１ＷＩ为等或稍高信号，Ｔ２ＷＩ为高信号。ＣＴ扫描为等或稍高密度影。ＭＲ和ＣＴ增强扫描可见均匀明显强化。结论：ＭＲ和ＣＴ检查对术前诊断脉络丛乳头状瘤很有帮助，并可清楚地显示肿瘤及其与周围组织的关系。ＭＲ扫描对脉络丛乳头状瘤的显示远远优于ＣＴ。     

脉络膜裂影像学表现及脉络膜裂神经上皮囊肿的诊断

目的探讨脉络膜裂的影像学表现和脉络膜裂神经上皮囊肿的影像表现,提高其鉴别诊断水平。方法结合文献和颅脑大体标本,对照研究正常脉络膜裂在MR上的影像学表现,并对14例脉络膜裂神经上皮囊肿进行CT和MR I分析。结果MR可清楚地显示脉络膜裂全长,表现为含脑脊液裂隙。脉络膜裂神经上皮囊肿表现为圆形或椭圆形、边界光滑锐利的脑脊液样低密度或信号,增强扫描无强化,近期随访囊肿无明显变化。结论认识脉络膜裂影像学表现和脉络膜裂神经上皮囊肿的CT和MR I表现,有利于正确诊断,减少误诊。     

Choroid plexus changes after temporal lobectomy

BACKGROUND AND PURPOSE: Postoperative contrast-enhanced MR imaging of the brain is routinely used when evaluating for residual or recurrent brain tumor. It is imperative to be aware of morphologic changes and imaging features that typically occur in response to surgical manipulation at the postoperative site to avoid misinterpretation of imaging findings. Our purpose was to determine normal postoperative changes and alterations in the choroid plexus among patients who had undergone temporal lobectomy in order to distinguish this appearance from pathologic changes that may be seen in the presence of infection or recurrent tumors. METHODS: We reviewed 159 MR scans from 95 patients with hippocampal sclerosis or gliosis who underwent temporal lobectomy for treatment of intractable epilepsy. Choroid plexus location and size were assessed on contrast-enhanced T1-weighted images. RESULTS: After temporal lobectomy, the choroid plexus enlarged and sagged into the resection site. Increase in the size of the choroid plexus occurred in 58% of cases overall. The degree of enhancement also increased after surgery, sometimes resulting in a nodular pattern of enhancement. The changes were most marked during the 1st week after temporal lobectomy, and showed an enlarged, markedly enhancing choroid plexus on 86% of the scans. CONCLUSION: Postoperative changes of the choroid plexus after temporal lobectomy include sagging into the resection site, an increased size, and an increased degree of enhancement. Normal postoperative morphologic characteristics may mimic neoplastic enhancement pattern. Familiarity with this appearance is important to avoid a pitfall in diagnosis of recurrent postoperative temporal lobe neoplasms.     

Lateral ventricular neoplasms of the brain: differential diagnosis based on clinical, CT, and MR findings

The differential diagnosis of lateral ventricular tumors was explored by retrospective analysis of 47 pathologically proved cases identified by CT and/or MR imaging. Third ventricular tumors adjacent to the foramen of Monro (e.g., colloid cysts) were excluded. Forty-six patients underwent CT, and eight had MR imaging. The most common neoplasms were choroid plexus papilloma (10 cases) and meningioma (nine cases). Other common neoplasms included subependymoma (six cases), subependymal giant cell astrocytoma (five cases), and metastasis/lymphoma (four cases). Important features for differential diagnosis included age of the patient, the tumor's location within the lateral ventricle, and density on CT before IV administration of contrast material. Fifty percent of the tumors were in the ventricular atrium. All intraventricular tumor types (except subependymoma) showed contrast enhancement. MR was most useful in evaluating tumor location, size, and extent, but it did not help in eliminating alternative diagnoses. On the basis of patients' ages, specific tumor location, and the appearance on CT scans or MR images, an algorithm for differential diagnosis of lateral ventricular tumors was developed.     

Lateral ventricular neoplasms of the brain: differential diagnosis based on clinical, CT, and MR findings

The differential diagnosis of lateral ventricular tumors was explored by retrospective analysis of 47 pathologically proved cases identified by CT and/or MR imaging. Third ventricular tumors adjacent to the foramen of Monro (e.g., colloid cysts) were excluded. Forty-six patients underwent CT, and eight had MR imaging. The most common neoplasms were choroid plexus papilloma (10 cases) and meningioma (nine cases). Other common neoplasms included subependymoma (six cases), subependymal giant cell astrocytoma (five cases), and metastasis/lymphoma (four cases). Important features for differential diagnosis included age of the patient, the tumor's location within the lateral ventricle, and density on CT before IV administration of contrast material. Fifty percent of the tumors were in the ventricular atrium. All intraventricular tumor types (except subependymoma) showed contrast enhancement. MR was most useful in evaluating tumor location, size, and extent, but it did not help in eliminating alternative diagnoses. On the basis of patients' ages, specific tumor location, and the appearance on CT scans or MR images, an algorithm for differential diagnosis of lateral ventricular tumors was developed.     

The bright choroid plexus on MR: CT and pathologic correlation

Fourteen patients studied with MR imaging were found, incidentally, to have unusually bright, large choroid plexus glomera on T2-weighted sequences. A group of 167 patients was then examined retrospectively for size and intensity of the choroid plexus glomera on T2-weighted images. In the latter group of 167 patients, 66 (39.5%) had bright choroid plexus glomera. Of those who had bright choroid plexus glomera, eight of the 14 initial group and 11 of the 66 patients studied retrospectively had previous CT scans. The typical CT appearance of these bright glomera consisted of nonenhancing central regions of low (but not negative) attenuation with peripheral calcifications in the majority. The remainder showed noncalcified glomera. Fifty-two glomera were obtained at autopsy and examined retrospectively. Eight showed small, variably sized masses with lipid deposits, neuroepithelial microcysts, and peripheral psammoma body calcifications. One patient who died had a bright choroid plexus glomus on MR, and his glomera showed the same pathologic findings. The autopsy findings were believed to be typical pathologically for early xanthogranulomata formation. These early xanthogranulomatous changes appear to be of little clinical significance but must be differentiated from other lesions that can produce bright or enlarged choroid plexus glomera on MR.     

Choroid plexus size in young children with Sturge-Weber syndrome.

PURPOSETo assess the size of the choroid plexus in young children with unilateral and bilateral Sturge-Weber syndrome.METHODSSubjects included 15 children 4 years old or younger with Sturge-Weber syndrome. Eleven cases were unilateral and four were bilateral. Unilateral or bilateral involvement was determined by the distribution of abnormal leptomeningeal enhancement on MR images. The diameters of the choroid plexus were measured on contrast-enhanced axial MR images. The choroid plexus of the affected and unaffected sides in these cases were compared with those of 15 age-matched children without Sturge-Weber syndrome who were being examined for seizures.RESULTSOur results show a wide variation in the size of the choroid plexus in children with Sturge-Weber syndrome; however, plexus associated with a hemisphere affected by Sturge-Weber syndrome were significantly larger than those on the unaffected side and in the age-matched control group. The size of the choroid plexus was positively correlated with the extent of leptomeningeal involvement as demonstrated by abnormal contrast enhancement.CONCLUSIONThe choroid plexus is enlarged early in the course of Sturge-Weber syndrome in both unilateral and bilateral cases. There is a positive correlation between choroid plexus size and extent of leptomeningeal involvement in children with Sturge-Weber syndrome.     

Pediatric choroid plexus neoplasms: MR, CT, and pathologic correlation

Choroid plexus papillomas are rare, constituting approximately 0.5% of all intracranial neoplasms. Four benign choroid plexus papillomas and one choroid plexus carcinoma were retrospectively reviewed in patients aged 4-20 months who had been examined with magnetic resonance (MR) imaging with a field strength of 0.5 T or 1.0 T and with computed tomography (CT) before and after the administration of contrast material. In general, the tumors were of intermediate signal intensity on T1-weighted images and of either intermediate or increased signal intensity (T2 lengthening) with T2 weighting. All demonstrated variable areas of internal signal void interpreted as signifying regional blood flow, calcification, or old hemorrhage. CT findings included relatively uniform contrast enhancement. Microscopic pathologic changes of the benign lesions mimicked the appearance of normal choroid plexus and confirmed the highly vascular nature of these tumors. MR imaging, with its high-resolution multiplanar techniques, offers direct visualization of these lesions in relation to normal anatomy and better discrimination and confirmation of their intraventricular location, facilitating surgery and postoperative follow-up.     

Quantitative short echo time 1H-MR spectroscopy of untreated pediatric brain tumors: preoperative diagnosis and characterization

PURPOSE: Our aims were to evaluate the metabolic profiles of pediatric brain tumors with short echo time (TE) MR spectroscopy and absolute quantitation of metabolite concentrations (in mmol/kg of tissue) and to describe metabolic features that distinguish individual tumor types and that may help to improve preoperative diagnosis of specific tumors. METHODS: MR imaging examinations of 60 patients with untreated brain tumors (14 medulloblastomas, 5 anaplastic astrocytomas, 3 low-grade astrocytomas, 17 pilocytic astrocytomas, 4 anaplastic ependymomas, 5 ependymomas, 3 choroid plexus papillomas, 3 choroid plexus carcinomas, and 6 pineal germinomas) were reviewed. Single-voxel proton MR spectroscopy with a TE of 35 ms was performed and absolute metabolite concentrations were determined by using fully automated quantitation. RESULTS: Taurine (Tau) was significantly elevated in medulloblastomas (P < .00001) compared with all other tumors pooled (All Other). Tau was also observed consistently, at lower concentration, in pineal germinomas. Creatine (Cr) was significantly reduced in pilocytic astrocytomas, distinguishing them from All Other (P < .000001). The MR spectra of choroid plexus papillomas exhibited low Cr (P < .01) concentrations; however, myoinositol was elevated (P < .01) and total choline (tCho) (P < .0001) was reduced relative to All Other. Choroid plexus carcinomas had low Cr (P < .01 versus All Other) and the lowest Cr/tCho ratio (P < .0001 versus All Other) among all tumors studied. Guanidinoacetate was reduced in low-grade astrocytomas and anaplastic astrocytomas (P < .00001) versus All Other, whereas ependymoma and anaplastic ependymomas exhibited particularly low N-acetylaspartate (P < .00001 versus All Other). CONCLUSION: Quantitative proton MR spectroscopy reveals features of pediatric brain tumors that are likely to improve preoperative diagnoses.