原发性中枢神经系统淋巴瘤的MRI与~1H-MRS研究

目的:探讨免疫功能正常人原发性中枢神经系统淋巴瘤(PCNSL)的常规MRI及多体素质子磁共振波谱(1H-MRS)表现。方法:对15例经病理证实的PCNSL的MRI和1H-MRS表现进行回顾性分析。结果:15例患者共检出24个病灶,其MRI及1H-MRS表现如下:①PCNSL的MRI表现:病灶T1WI呈低或等信号,T2WI呈等或稍高信号;DWI呈高信号;增强后病灶明显均匀强化,"缺口征"、"尖角征"的出现具有特异性;②PCNSL的1H-MRS表现:肿瘤实质区及瘤周近侧水肿区Cho峰升高及NAA、Cr峰降低,肿瘤实质区可见升高的Lip峰。4例病灶在正常组织区可见异常谱线。结论:传统MRI结合1H-MRS表现能够显著提高PCNSL的诊断与鉴别诊断水平;1H-MRS对于肿瘤浸润及多发病灶的显示优于传统MR检查。     

颅内血管外皮细胞瘤的MRI与病理结果(附13例报告)

目的 探讨颅内血管外皮细胞瘤的MRI表现，并与病理对照，分析误诊原因。资料与方法搜集术前MRI诊断脑膜瘤，而手术证实为血管外皮细胞瘤13例，所有病例均行MR平扫及增强扫描。结果 13例MRI示肿瘤位于颅内脑外，MR平扫TlWI呈高低不均信号9例，等信号4例；T2WI呈不均匀高信号9例，等信号4例；增强扫描11例呈不均匀强化。术后病理证实肿瘤来源于脑膜间质的血管外皮细胞。结论 颅内血管外皮细胞瘤MRI表现与脑膜瘤相似，但前者往往出现分叶征，有丰富的血管，肿瘤易出血、坏死致信号不均匀，无钙化及局部骨质反应性增生和有溶骨性破坏等特点，据此可资鉴别。病理免疫组织化学可确定肿瘤的起源。     

颅内原发性淋巴瘤的影像学表现

目的：通过分析颅内原发性淋巴瘤（PCNSL）的影像学表现,提高PCNSL的早期诊断水平。方法：回顾性分析7例病理确诊的PCNSL的CT和MRI表现,观察病灶的分布、形态、信号特点及强化特征。结果：7例中,5例单发,2例多发,均位于幕上;共13个病灶,位于大脑半球深部5个,灰白质交界区4个,胼胝体3个,基底节区1个;CT示略高密度10个,混杂密度3个;MRI示T₁WI呈等低信号,T₂WI呈高信号,DWI呈高信号,瘤周水肿及占位效应均较轻。结论：PCNSL预后不良,生存期较短,临床表现无特异性,影像表现多样化,早期确诊难度较大;认识其CT、MRI特征性表现可为临床治疗方案的选择提供重要依据。     

MRI对原发性中枢神经系统淋巴瘤的诊断

目的 探讨原发性中枢神经系统淋巴瘤(primary central nervous system lymphoma,PCNSL)的MRI特点,提高对PCNSL的认识和诊断水平.方法 回顾性分析21例经手术病理或穿刺活检证实的PCNSL的MR表现,并结合文献研究MRI特征.结果 单发7例,多发7例,弥漫性生长7例,共33个肿瘤,其中额叶12个,脑室旁8个,颞叶、顶叶、透明隔、小脑蚓部各2个,枕叶、基底节区、丘脑、脑干、小脑各1个; 4例肿瘤累及胼胝体.肿瘤实质MR T1WI呈等或稍低信号,T2WI呈等或稍高信号,信号较均匀;18例肿瘤实质强化明显,信号均匀,可呈现"尖角征"和"脐凹征"及具有特征性的"蝴蝶征",3例出现环形强化.结论 PCNSL MR检查具有特征性表现,MRI检查对PCNSL具有独特的诊断价值.     

原发性中枢神经系统淋巴瘤的磁共振成像表现

目的探讨原发性中枢神经系统淋巴瘤（PCNSL）的磁共振成像（MRI）特征及鉴别诊断。方法回顾性分析15例经手术病理证实的PCNSL的MRI表现。结果病理检查均为B细胞来源的弥漫性大B细胞性淋巴瘤。15例PCNSL19个病灶,单发13例（87％）,多发2例（13％）共6个病灶。病灶常位于脑表浅部位和近中线部位,T1wI呈等或稍低信号,T2WI及液体衰减反转恢复序列（FLAIR）呈等或稍高信号,弥散加权成像（DWI）呈高信号。所有病灶均明显强化,增强后病灶大多呈均匀实质团块状或结节状强化,典型的可出现“尖角征”、“握拳征”,3例可见小囊变,呈“硬环征”。结论PCNSL的MRI表现具有一定的特征性,术前MRI检查有助于诊断及鉴别诊断,结合患者影像学及临床资料,术前可作出明确诊断。     

成人颅内原始神经外胚层肿瘤的MRI表现和病理对照

目的 探讨成人颅内原始神经外胚层肿瘤(primitive neuroectoderrnal tumors，PNET)的MRI特征，以期提高对该病的认识。方法回顾性分析了7例经手术和病理证实的成人颅内PNET的MRI表现，并与手术、病理相对照。结果 肿瘤多位于大脑半球和小脑蚓部，浸润性生长，瘤组织由低分化的小细胞构成，形态上可向多种细胞过渡。(2)MRI上肿瘤较大，4例呈浅分叶状，边界较清楚，瘤周水肿轻微；平扫呈不均匀较低T1、等或高T2信号，内部常伴有囊变和坏死区、可有出血和钙化；增强扫描6例肿瘤有明显的不均一强化；2例发生颅内转移，1例术后发生腰椎转移。结论 成人颅内PNET的MRI表现有一定特点；MRI有助于该病的诊断和指导治疗。     

嗅神经母细胞瘤的CT和MRI表现

目的探讨嗅神经母细胞瘤（ONB）的CT和MRI诊断价值。资料与方法对23例经病理证实的ONB患者CT（21例）和MRI（14例）资料进行回顾性分析。结果肿块中心位于鼻腔顶部的中后方17例；位于鼻腔顶部的前方2例；位于中鼻道、筛窦、上颌窦和鼻咽部各1例。形态规则13例，不规则10例。CT像上肿块密度多不均匀，CT值30～60HU，3例见钙化，1例见囊变。18例邻近骨质破坏。MRI示肿块信号多不均匀，在T1WI以等或略低信号为主，T2WI以等或稍高信号为主，明显强化。肿瘤侵犯筛窦19例，颅内16例，眼眶15例。结论鼻腔顶部肿块并穿越筛板侵犯嗅沟区，是ONB的特征性表现。CT可清楚显示肿瘤周围骨质情况，MRI能准确显示肿瘤侵犯范围，两者结合更有利于制定治疗方案。     

颅内血管外皮细胞瘤的MRI诊断

目的探讨颅内血管外皮细胞瘤(hemangiopericytoma,HPC)的MRI特征,提高其诊断的准确率。方法回顾性分析经手术病理证实的11例颅内HPC的MRI表现。结果 11例肿瘤均位于颅内脑外,9例(81.82%)肿块呈多分叶状,MR T1WI上呈不均匀等或稍低信号,T2WI上呈不均匀等或稍高信号;7例(63.64%)于扩散加权成像(DWI)上呈混杂等或稍高信号,10例(90.91%)肿瘤内部或边缘可见明显流空血管影。增强扫描11例均呈明显不均匀强化,仅2例(18.18%)示"脑膜尾征"。结论颅内HPC的MRI表现有一定的特征性,有助于提高HPC的术前诊断率。     

颅内原发性中枢神经系统淋巴瘤的MRI表现

目的研究颅内原发性中枢神经系统淋巴瘤（PCNSL）的MR／表现特点。方法回顾性分析8例经手术病理证实的原发性中枢神经系统淋巴瘤的MR／表现。结果8例均为弥漫大B细胞型非霍奇金淋巴瘤。3例为单发,5例为多发,共13个病灶,其中大脑半球8个,基底节区4个,右侧背侧丘脑及基底节区1个。8例病变均表现为局灶性肿块,T1WI呈稍低或等信号;T2WI呈等或稍高信号。增强扫描7例呈明显均匀强化,1例轻度强化。6例瘤周重度水肿,2例瘤周中度水肿。结论原发性中枢神经系统淋巴瘤较为罕见,MRI是诊断该病的重要的无创性检查方法。颅内PCNSL影像学表现多样,但具有一定特征。     

CT和MRI对颅内表皮样囊肿诊断价值的评价

目的：评估CT和MRI对颅内表皮样囊肿的诊断价值，分析误诊原因，提高诊断水平。方法：44例经手术和病理证实的颅内表皮样囊肿，术前全部行常规MRI检查，其中19例行Gd-DTPA增强MRI检查；17例作CT平扫，其中12例作静脉注射增强CT检查。结果：颅内表皮样囊肿多位于桥小脑角池，本组病例中占34．9％(15／4例)；肿瘤多呈不规则形态，占70．45％(31／44例)；CT平扫多呈均匀低密度，占70．59％(12/17例)，造影后多无强化，占91．71％(11／12例)；MRT1加权像上多呈均匀低信号，但略高于脑脊液，T2加权像上多呈均匀高信号，占61．36％(27／44例)，Gd-DTPA增强后多无强化，占84．21％(16／19例)。肿瘤周围的脑组织均无水肿，占100％，肿瘤较大时可以挤压、推移周围脑组织或脑室结构，引起比较明显的占位效应，占70．45％(31／44例)；肿瘤较大时，很少引起阻塞性脑积水。结论：颅内表皮样囊肿在CT和MRI像上有特征性表现，MRI无论在定位和定性诊断上优于CT，Gd-DTPA的应用有助于颅内囊性占位的诊断与鉴别诊断。     

Wegener granulomatosis: MR imaging findings in brain and meninges

PURPOSE: To determine the spectrum of intracranial magnetic resonance (MR) imaging appearances of Wegener granulomatosis. MATERIALS AND METHODS: MR imaging studies in 19 patients with Wegener granulomatosis and possible central nervous system involvement were reviewed by two neuroradiologists. Intermediate-weighted and T2-weighted fast spin-echo MR images of the brain had been acquired in all patients, and spin-echo T1-weighted nonenhanced and gadolinium-enhanced images had been acquired in 18 patients. RESULTS: MR imaging findings included diffuse linear dural thickening and enhancement (n = 6); focal dural thickening and enhancement contiguous with orbital, nasal, or paranasal disease (n = 5); infarcts (n = 4); nonspecific white matter areas of high signal intensity on intermediate-weighted and T2-weighted images (n = 10); enlarged pituitary gland with infundibular thickening and enhancement (n = 2); a discrete cerebellar lesion that was probably granulomatous in origin (n = 1); and cerebral (n = 8) and cerebellar atrophy (n = 2). CONCLUSION: MR imaging demonstrated the wide spectrum of findings of central nervous system involvement in patients with Wegener granulomatosis and was particularly useful for the evaluation of direct intracranial spread from orbital, nasal, or paranasal disease.     

The variable MR appearance of primary lymphoma of the central nervous system: comparison with histopathologic features.

PURPOSETo describe the MR features of primary central nervous system (CNS) lymphoma and to determine whether there is a correlation with histopathologic findings.METHODSThe MR images, pathologic specimens, and clinical records of 23 patients with primary CNS lymphoma were reviewed. The imaging and pathologic characteristics were tabulated and compared by using the standard tests for association in a two-dimensional contingency table.RESULTSA total of 61 lesions were present in 23 patients; 12 patients (52%) had multiple lesions. All lesions were isointense or hypointense on T1-weighted images, and 53% were isointense or hypointense on T2-weighted images. Twenty patients received intravenous contrast material, and 43 (91%) of 47 lesions enhanced. The three patients who had nonenhancing lesions received steroids before the initial MR studies. Enhancement patterns differed between the immunocompetent and the immunocompromised hosts, with the latter group harboring a higher percentage of rim-enhancing lesions. Twenty-seven (44%) of the lesions were centered in a cerebral hemisphere and 14 (23%) were centered in the central gray matter. There was a statistically significant correlation between a higher degree of necrosis histologically and hyperintensity on T2-weighted MR images. The degree of necrosis also showed a positive correlation with rim enhancement.CONCLUSIONSPrimary CNS lymphoma has a variable MR appearance that correlates with the severity of intratumoral necrosis. These imaging characteristics, as well as lesion location, mean lesion size, and proclivity to harbor necrosis, are altered in the immunocompromised host.     

Radiographic findings in 37 cases of primary CNS lymphoma in immunocompetent patients

Because of the increasing incidence of primary central nervous system lymphoma (PCNSL), it is essential to recognize this disease in order to start appropriate treatment. We present the characteristic CT and MRI features of this tumour. The findings of 32 CT and 31 MR of 37 immunocompetent patients with biopsy-proved PCNSL are reviewed. The main features are presented and analysed, and are discussed in comparison with proven literature data. Primary central nervous system lymphoma presents as supratentorial solitary lesions in approximately 80% of the patients and multiple lesions in 20%. In contrast to classical data, the lesions are located in deep structures only in one-third of the cases, and involve posterior fossa in 10% of cases. Most of the lesions are hyperdense or isodense (92%) on CT, hypointense or isointense on T1-weighted images, and only about 40% are hyperintense on T2-weighted images. Nearly all the lesions enhance, except after corticosteroid administration. They produce mild oedema and mass effect. Meningeal or ventricular enhancement are rare but suggestive. Calcification, haemorrhage or necrosis are scarce. Although PCNSL in immunocompetent patients have a variable CT and MR appearance, the imaging data often suggest the diagnosis.     

原发性中枢神经系统淋巴瘤的影像学表现

目的：探讨原发性中枢神经系统淋巴瘤的影像学表现,以提高影像诊断水平。方法回顾性分析25例经病理证实的原发性中枢神经系统淋巴瘤的CT、MRI等影像学资料。结果单发16例,多发9例,共有39个病灶,幕上35个病灶,幕下4个病灶。单发病灶多位于脑白质深部,多发病灶常位于脑实质中线部位及大脑凸面。肿瘤在CT表现呈稍高密度,病灶T1WI多呈等或稍低信号,T2WI多呈等或稍高信号,DWI多呈高信号。增强扫描多呈明显均匀强化,少数呈斑片状强化;瘤周可见不同程度的水肿。结论原发性中枢神经系统淋巴瘤的CT、MRI表现具有一定特征性,结合临床并综合其影像学表现,可提高其诊断准确率。     

Conventional and diffusion-weighted MR imaging of intracranial tuberculomas. A case report

 Intracranial tuberculoma is a rare form of central nervous system tuberculosis. We here report on conventional and diffusion-weighted cranial MR images of a non-immunocompromised patient with multiple intracranial tuberculomas, tuberculous lymphadenitis and pulmonary tuberculosis. Conventional MR imaging revealed multiple ring-enhancing mass lesions. At follow-up MR, appearances of both edema and number and size of nodules were decreased. Diffusion-weighted MR was normal and normal ADC values were found in this case of tuberculomas.     

颅内原发淋巴瘤MRI表现（附8例分析）

目的：结合病理基础分析颅内原发淋巴瘤的MRI特点,复习文献,探讨MRI新技术对颅内原发淋巴瘤诊断及鉴别诊断的意义。方法：搜集我院2007年11月～2009年2月经手术病理证实的颅内原发淋巴瘤8例,回顾性分析其MRI特征。结果：8例中B细胞性非霍奇金淋巴瘤6例,T细胞性2例。3例为单发病灶,5例多发。4例病变位于近中线深部脑组织,4例靠近脑表面。MRI平扫瘤体T1WI中等或稍低信号,T2WI及FLAIR中等或稍高信号。DWI多表现为高或稍高信号,增强扫描呈中等度强化。结论：颅内原发淋巴瘤的MRI表现有一定的特征性,常规检查的基础上联合使用MRI新技术,可提高其术前诊断正确率。     

Primary central nervous system lymphoma versus toxoplasmosis in AIDS

The imaging studies of 16 patients with acquired immunodeficiency syndrome (AIDS) and proved primary central nervous system (CNS) lymphoma were reviewed. All studies included computed tomography (CT); six also included magnetic resonance (MR) imaging. A periventricular lesion was seen in 50% of patients. At least one such lesion exhibited subependymal spread or ventricular encasement in 38%. One-third of lesions in three of five patients who underwent nonenhanced CT were hyperattenuating. Five lesions were at least in part hypointense on T2-weighted MR images. The specificity of these findings was evaluated with a similar review of the imaging studies in 28 patients with AIDS and proved toxoplasmosis. Only 3% of lesions were periventricular. None exhibited subependymal spread or encasement. None were hyperattenuating on nonenhanced CT scans. Similar findings in other CNS lesions in AIDS patients could not be found in the literature. A focal enhancing mass with subependymal spread on CT or MR images and hyperattenuation at nonenhanced CT were the most reliable features in distinguishing between primary CNS lymphoma and toxoplasmosis in AIDS patients.     

Non-Hodgkin lymphomas of the ovaries: MR findings

PURPOSE: The goal of this work was to describe MR findings (morphology, structure, signal intensity) of ovarian non-Hodgkin lymphoma (NHL). METHOD: We reviewed the MR images of five female patients aged 13-70 years (mean 46 years) with histologically proven NHL of the ovaries. We evaluated morphological and signal intensity findings of the lesions. MR features were correlated with pathologic parameters. RESULTS: All the patients were affected by B-cell NHL; one patient showed a primary involvement of the ovaries; in one patient, ovarian disease was diagnosed 30 months after surgical resection of a primary uterine lymphoma; the remaining three had a systemic lymphoma. In three cases, the ovarian involvement was bilateral. The mean size of the lesions was 7.9 cm. All the lesions showed homogeneous low signal intensity on T1-weighted images and intermediate to high intensity on T2-weighted images. The postgadolinium images showed mild to moderate heterogeneous enhancement. The peripheral enhancement was better demonstrated in fat-suppressed images. CONCLUSION: The diagnosis of primary ovarian lymphoma should be considered in the presence of large bilateral solid ovarian masses with homogeneous appearance (low signal on T1 and mildly high on T2) without infiltrative pattern of growth or regressive changes (necrosis, hemorrhage, calcifications) and with little contrast enhancement.     

MR imaging of intracranial tuberculomas

Eight patients with intracranial tuberculomas were studied with CT and magnetic resonance (MR) imaging. Large, ring enhancing, solid lesions on CT showed low intensity on T2-weighted images and intermediate intensity on T1-weighted images. Small lesions, with ring enhancement on CT, showed central bright signal on T2-weighted images with a peripheral low intensity rim surrounded by high intensity edema. The MR imaging features of the tuberculomas were found to be distinct from those of abscesses, metastases, and gliomas.     

脊柱区淋巴瘤的MRI特征

目的 分析脊柱区淋巴瘤的MRI表现,以提高对其的认识.方法 回顾性分析经手术及穿刺病理或临床随访证实的脊柱区淋巴瘤45例,其中原发性5例,均为非霍奇金淋巴瘤(NHL);继发性4|D例,其中霍奇金淋巴瘤(HL)9例,NHL 31例(B细胞型27例,T细胞型4例).将MRI表现与临床、病理结果进行对照.结果 (1)病变部位:单部位发病者13例,多部位发病者32例.5例原发性者均为单部位发病,继发性者40例中32例为多发.(2)病变类型:骨质破坏型27例,表现为不同程度的骨质破坏,23例合并有软组织肿块,18例软组织病变的范围超过骨质破坏的范围;软组织肿块型6例,骨质破坏不明显,5例表现为椎管内外软组织肿块并经椎间孔相连,呈围椎、钻孔生长的特点;骨髓浸润型9例,表现为椎骨髓质MRI信号异常,骨皮质完整,椎旁软组织正常;脊髓浸润型3例,表现为脊髓增粗和MRI信号异常.(3)MRI表现:椎骨骨质破坏和骨髓浸润表现为T1WI低信号,T2WI低、等或高信号,压脂T2WI高信号.软组织肿块与相邻正常肌肉相比,T1WI呈均匀低信号,T2WI呈高信号.增强扫描肿块多呈轻至中度强化,坏死液化不明显.结论 脊柱区淋巴瘤多为继发性B细胞NHL,其主要表现是溶骨性骨质破坏伴较大范围的软组织肿块,肿块有经椎间孔相连围椎、钻孔生长的特点,增强扫描呈轻至中度均匀强化.