半球形与扁平形葡萄膜转移瘤MRI征象对比研究

目的对比分析半球形与扁平形葡萄膜转移癌的MRI征象,探讨MRI对不同形态葡萄膜转移癌的诊断价值。方法回顾性收集北京同仁医院2005～2015年经手术病理或临床综合诊断确诊的眼葡萄膜转移癌49例,平均年龄(52.5±12.3)岁,其中男性19例,女性30例,左眼26例,右眼21例,双眼2例,根据病变形态分为扁平形组(36例)和半球形组(13例)。比较两组临床表现及MRI征象,包括患者年龄、性别、肿块侧别、部位、形态、边缘、是否伴发视网膜脱离、T_1WI和T_2WI信号(与脑灰质相比)、T_1WI和T_2WI信号均匀度、强化程度、强化均匀度、强化指数、肿块高度、基底径、基底径与高度比值,计数资料采用Pearson卡方检验,计量资料采用独立样本秩和检验。结果肿块T_1WI信号均匀度、增强程度、强化指数在两组间均有显著差异﹙χ~2=4.491、5.026、5.914,P=0.034、0.025、0.015),患者性别、侧别、肿块部位、形态、边缘、是否伴发视网膜脱离、T_1WI和T_2WI信号(与脑灰质相比)、T_2WI信号均匀度均无显著性差异(P0.05),基底径与高度比值在扁平形组(0.8～11.3mm,中位数2.9mm)和半球形组(1.0～6.0mm,中位数2.0mm)两组间均有显著差异(Z=-1.998,P=0.046),患者年龄、肿块高度、基底径均无显著性差异(P 0.05)。结论半球形与扁平形葡萄膜转移癌的MRI征象存在一定差异,半球形葡萄膜转移癌仍具备多数葡萄膜转移癌T_1WI、T_2WI多呈等信号的特点,MRI对葡萄膜转移癌具有重要价值。     

葡萄膜黑色素瘤的MRI诊断

目的探讨MRI对葡萄膜黑色素瘤的诊断价值。资料与方法对35例葡萄膜黑色素瘤患者行MRI横断面、冠状面、斜矢状面平扫及增强扫描。结果35例黑色素瘤患者中27例在T1WI表现为高信号,8例为等信号,T2WI上均为低信号,增强后为中度至明显强化。21例继发的视网膜脱离在T1WI上为高信号,T2WI上为等或高信号,无强化。结论MRI可对肿瘤进行精确定位,同时能显示肿瘤的大小和信号特征,有助于对葡萄膜黑色素瘤的诊断及鉴别诊断。     

视网膜脱离的MRI诊断价值

目的:探讨视网膜脱离的MRI表现及诊断价值。方法:回顾性分析经手术和临床证实的16例(17只眼)视网膜脱离患者的MRI图像特征。结果:部分性脱离11例(12只眼),完全性脱离5例;脱落部位以累及视乳头双侧者较多见(9/17),发生于单侧者多位于颞侧(6/8);脱落的形态多呈"v"字形(8/17)和月牙形(6/17),其次不规则弧形(3/17);病变信号强度T1WI以等或稍高信号为主(16/17),仅1例呈稍低信号,T2WI信号均高于玻璃体信号;合并玻璃体出血、混浊5例,脉络膜黑色素瘤1例,脉络膜脱离1例。结论:视网膜脱离的MRI表现较具特征性,MRI对视网膜脱离的诊断具有重要价值。     

眼球孤立性脉络膜血管瘤的HR-MRI表现

目的　探讨眼球孤立性脉络膜血管瘤的高分辨率磁共振 (HR MRI)影像学特征 ,进一步提高诊断水平。资料与方法　回顾性分析诊断明确的孤立性脉络膜血管瘤 16例共计 17个病灶的位置、数目、形态、大小、MRI信号、强化情况、有无合并视网膜脱离及有无视神经和眼外侵犯等。所有病例均行HR MRI及增强扫描 ,部分病例行脂肪抑制。结果　 17个病灶中的 16个呈扁丘状位于眼球内壁的后极。 15个病灶厚度 <5mm ,平均厚度为2 .9mm。病灶边缘清晰 ,T1WI上呈轻度高信号者 16个 ,T2 WI上呈等信号者 15个 ,增强扫描显著强化者有 12个。 3例合并视网膜脱离 ,在T2 WI上多呈等信号 ,T1WI上呈轻度高信号者 ,均无强化。无视神经及眼外侵犯病例。结论　 94 %孤立性脉络膜血管瘤的HR MRI表现具有特征性 ,表现为位于眼球内壁后极的较小、基底较宽、边缘清晰的扁丘状病灶。其T1WI信号高于玻璃体 ,T2 WI信号等于玻璃体 ,增强扫描瘤体显著强化。明确其HR MRI影像学特征有助于临床与恶性葡萄膜黑色素瘤相鉴别 ,避免不必要的眼球摘除     

眼球脉络膜黑色素瘤的CT和MRI表现

目的:分析眼球脉络膜黑色素瘤的CT和MRI表现,并探讨其在诊断和鉴别诊断中的价值.材料和方法:回顾性分析经手术和病理证实的25例眼球脉络膜黑色素瘤,其中CT扫描13例,MRI检查7例,CT加MRI检查5例.结果:本组仅1例肿瘤侵及球外,其余均局限于眼球内.3例为梭形,21例为蘑菇形.CT平扫密度较均匀,接近眼环密度;增强后12例呈明显均匀强化,3例不均匀强化.1例伴有斑片状钙化.14例显示肿瘤的一侧或两侧周边区半月形视网膜剥离.与玻璃体比较T1WI呈高信号,T2WI呈低信号.10例显示视网膜剥离,渗液在T1WI、T2WI上均呈中高信号.增强后T1WI示瘤体中等至明显强化,周边积液未见强化,仅1例周边积液显示中等强化.结论:CT与MRI均能显示眼球内的病灶,MRI对该病的诊断及鉴别诊断优于CT且具有特征性.     

颅内黑色素瘤MRI诊断

目的 探讨颅内黑色素瘤的MRI特征.方法 回顾性分析11例经手术病理证实的颅内黑色素瘤的MRI表现.结果 11例颅内黑色素瘤,共15个病灶,有14个位于幕上,10个病灶伴有出血,4个病灶局部囊变,大部分病灶有不同程度的水肿.颅内黑色素瘤MRI信号表现为:8个病灶T1WI为高信号、T2WI为低信号,3个病灶以T1WI为等信号、T2WI为低信号表现为主的混杂信号,2个病灶以等T1、等T2为主的混杂信号,2个病灶T1WI为低信号、T2WI为高信号;增强后均有不同程度的强化.结论 颅内黑色素性黑色素瘤MRI具有特征性的表现,对于无黑色素性黑色素瘤MRI表现无明显特征,诊断困难.     

虹膜睫状体肿瘤的MRI诊断探讨

目的 分析虹膜睫状体肿瘤的MRI表现,评价虹膜睫状体肿瘤MRI诊断价值.方法 回顾分析8例虹膜睫状体肿瘤MRI表现;8例均行MRI平扫,4例行MRI增强.结果 3例睫状体上皮腺瘤MRI均表现为与晶状体相连的类圆形软组织结节,T1WI和T2WI呈中等信号,MRI增强结节强化.2例睫状体黑色素瘤MRI表现为虹膜睫状体区不规则软组织结节,T1WI呈高信号,T2WI呈低或中等信号.1例虹膜淋巴瘤表现为晶状体、虹膜睫状体和前房内不规则软组织肿块,T1WI和T2WI均呈中等信号.1例虹膜血管平滑肌瘤表现为眼环前部类圆形结节,T1WI和T2WI均呈中等信号,MRI增强结节强化,同时合并视网膜脱离.1例睫状体神经纤维瘤MRI表现为晶状体附近类圆形结节,形状规则、边缘光滑,T1WI和T2WI呈均匀中等信号.结论 MRI可以显示虹膜睫状体肿瘤的大小、部位和种类,可以作为虹膜睫状体肿瘤影像学检查的主要方法.     

鼻道、鼻咽恶性黑色素瘤的MRI诊断

目的 分析鼻道、鼻咽恶性黑色素瘤的MRI表现,探讨其诊断要点.方法 回顾性分析经病理证实的8例鼻道、鼻咽恶性黑色素瘤的MRI特征及临床资料,所有患者均行MR平扫、增强及动态增强检查.结果 肿瘤位于中鼻道1例,鼻咽部2例,鼻腔、上颌窦及同侧筛窦5例.5例可见明显骨质破坏并侵犯邻近结构,累及翼腭窝3例、颞下窝2例、眼眶4例、前颅底2例、咽旁间隙1例.MRI表现:3例直径＜2 cm,呈类圆形肿块,T1WI为高信号,T2 WI为低信号,呈明显均匀强化.5例直径＞3 cm,不规则肿块,MRI表现为混杂信号,T1WI以等、低信号为主,其内有斑片状高信号;在T2WI,1例以等低、信号为主,4例以稍高信号为主,增强扫描呈轻度不均匀强化.动态增强扫描时间-信号强度曲线平台型、流出型各4例.结论 鼻道、鼻咽恶性黑色素瘤MRI信号特征与肿瘤大小相关.肿瘤较小时T1WI呈高信号,T2WI呈低信号;肿瘤较大时MRI信号混杂,轻度不均匀强化为其特征.     

眼球脉络膜血管瘤的影像学表现

目的：探讨眼球脉络膜血管瘤的CT、MRI表现及其诊断、鉴别诊断价值。方法：回顾性分析9例经病理（3例）和临床证实（6例）的脉络膜血管瘤。CT扫描6例，MR检查4例，9例均行B超检查，3例作了眼底荧光血管造影。结果：2例CT平扫示眼球后极球壁轻度或新月形增厚，与球壁呈等密度，5例（1例平扫＋增强）增强示眼球后极部高密度梭形或扁平状隆起均匀肿块，瘤体强化明显。与玻璃体比较3例MR T1WI呈高信号，T2WI呈低信号，与视神经、眼外肌相比呈等信号；1例较小肿瘤辅以增强T1WI脂肪抑制技术被清楚显示。渗出性视网膜脱离在T1WI、T2WI上均呈中、高信号；增强T1WI瘤体显著强化，边界清晰，且信号均匀。B超检查8例为实质不均质肿块占位，1例为均质肿块占位，9例均探及视网膜脱离光带。结论：CT＋MRI＋B超检查对脉络膜血管瘤可得到较为全面的影像学诊断资料，MRI在该病的诊断及鉴别诊断中较CT及B超更具敏感性和特异性。     

伽玛刀治疗脉络膜黑色素瘤近期疗效的MRI观察

目的对比脉络膜黑色素瘤(choroidal melanoma)伽玛刀(gamma knife radiosurgery,GKS)治疗前后的MRI表现,探讨MRI对评估GKS近期治疗效果及预后的价值。方法回顾性分析27例脉络膜黑色素瘤患者GKR治疗前及治疗后3个月的MRI表现。结果 27例均为单眼单病灶,左眼15例,右眼12例。T1WI显示17例(63%)呈高信号,10例(37%)呈等信号;T2WI显示均为低信号;脂肪抑制T1WI均为明显高信号。3例瘤体信号显示欠均匀。15例行增强扫描,肉眼观察呈中等至明显强化,其中12例均匀强化,3例不均匀强化。8例可见视网膜脱离。1例伴有球外侵犯,眼睑软组织增厚,有明显强化。GKS后3个月17例瘤体不同程度缩小,10例无变化,未见体积增大者;肿瘤缩小程度分为4个等级:0%～25%者15例,26%～50%者4例,51%～75%者3例,76%～100%者5例,局部有效控制率为100%。1例伴视网膜脱离者脱离范围较治疗前缩小。伴有球外侵犯者眼睑软组织增厚及强化程度较前明显减轻。瘤体信号与治疗前相比无明显变化。结论 MRI不仅是脉络膜黑色素瘤不可替代的检查手段,而且在GKS治疗近期疗效评价及预后方面也具有重要参考价值。     

眼色素膜黑色素瘤的CT与MRI研究

目的研究色素膜黑色素瘤的ＣＴ和ＭＲＩ表现，探讨最佳ＭＲＩ的扫描序列。材料与方法１５例患者用各种ＭＲＩ序列进行扫描，其中１１例行ＣＴ扫描，并与手术病理进行对照。结果ＣＴ示９例表现为与眼外肌等密度的肿块，２例肿瘤太小未能显示。ＭＲＩ示１４例具有典型的短Ｔ１、短Ｔ２信号，１例３ｍｍ高度的虹膜黑色素瘤在Ｔ１ＷＩ上未能显示；１１例伴有视网膜脱离，呈短Ｔ１及长Ｔ２信号，与肿瘤在Ｔ１ＷＩ上很难区分。使用脂肪抑制和增强扫描的Ｔ１ＷＩ能较好地显示较小肿瘤（高度＜５ｍｍ）能区分肿瘤及其伴发的视网膜脱离。结论ＭＲＩ显示黑色素瘤的准确率和特异性较ＣＴ和Ｂ超优越。     

Intraocular metastases: differential diagnosis from uveal melanomas with high-resolution MRI using a surface coil

Magnetic resonance imaging with dedicated surface coils plays a pivotal role in differential diagnosis and staging of intraocular tumors. The purpose of this study was to establish MRI criteria for the differential diagnosis of uveal melanomas and intraocular metastases. In a prospective study 44 eyes in 36 patients with intraocular metastases and 200 patients with uveal melanomas were investigated with MRI using a 1.5-T scanner and a 5-cm surface coil. Both quantitative and qualitative evaluation of the resulting images was performed. The MR signal intensities typically expected for metastases (slightly hyperintense on non-contrast T1-weighted images and hypointense on T2-weighted images compared to the vitreous body) were seen in only 23.1%. The typical melanoma signal of either moderate or strong hyperintensity on T1-weighted images and hypointensity on T2-weighted images was seen in 69.4% of the proven melanomas. Contrast enhancement was observed in both metastases and melanomas. Morphological differences between metastases and melanomas were detected in tumor size, shape, position, frequency of retinal detachment, and homogeneity of the tumor. Differentiation between intraocular metastases and uveal melanoma is limited by overlap of signal intensities. Some improvement is achieved with morphologic criteria.     

Malignant uveal melanoma and simulating lesions: MR imaging evaluation

Twenty-one patients with intraocular disease were studied by magnetic resonance (MR) imaging and computed tomography (CT). In 13 cases, malignant uveal melanoma was considered the likely diagnosis. Both imaging methods were accurate in determining the location and size of uveal melanomas. MR imaging was superior for the assessment of possible associated retinal detachment, for assessment of vitreous change, and for differentiating uveal melanoma from choroidal hemangioma and choroidal detachment. A case of retinal gliosis could not be differentiated from uveal melanoma by either technique. Uveal melanomas appeared as hyperintense lesions on T1-weighted images and as hypointense lesions on T2-weighted images. High signal intensity of the vitreous was observed in patients with vitritis and in those who were thought to have protein leaking into the vitreous as a result of impairment of the retinal-blood barrier.     

Imaging characteristics of the postoperative globe: a pictorial essay

Recognizing imaging characteristics after ophthalmic surgery is necessary for radiologists to prevent misdiagnosis. We review typical appearances of intraorbital implanted devices and materials on CT and MRI with demonstration of the common surgical procedures. EX-PRESS glaucoma filtration devices appear as punctate areas of metal attenuation on CT and are typically placed at the corneoscleral junction. The imaging manifestations after cataract extraction are absence of the native lens of ovoid mass and the intraocular lens with high attenuation on CT and low signal intensity on MRI. The treatment of retinal detachment is achieved with intraocular tamponade or scleral buckling. In intraocular tamponade, the eye is filled with a bubble of gas or silicone oil. Gas results in air attenuation on CT and low signal intensity on MRI in the vitreous cavity. Silicone oil is hyperattenuating on CT and has variable intensity on MRI. In scleral buckling, the eye wall is indented with silicone buckling elements that show high or low attenuation on CT and low T1- and T2-weighted intensity on MRI. Degraded hydrogel buckling elements appear as swollen masses showing low attenuation on CT and high T2-weighted intensity on MRI.     

脑结核瘤的磁共振成像

目的 分析颅内结核的磁共振表现。材料与方法 对12例脑结核瘤MRI表现及Gd-DTPA强化的特点进行回顾性分析。T1WI和T2WI信号强度与正常脑灰质进行比较。结果 3例粟粒样脑结核瘤呈脑内散在的多发等或略长T1、长T2信号,结节样均匀强化或伴有少量小环状强化。9例31个成熟结核瘤由环壁和坏死的核心两部分组成,环壁呈等T1、短T2信号（5个病灶）和等或略长T1、等或略长T2信号（26个病灶）,单环或花簇状环状强化;14个未成熟结核瘤呈结节样等或略长T1、长T2信号,均匀强化。成熟结核瘤的核心部分因组织病理学的差异可有多种信号。颅内结核瘤以1个主灶伴多个小灶为其主要表现形式（77.8%,7/9）。结论 T1WI呈等或略高信号,T2WI呈轻度不均匀等或略低信号,不均匀单环或花簇环状强化是结核的主要MRI表现。而病灶的多发性符合脑结核系血行播散所致的发病机理,对确立诊断有非常重要的价值。     

眼部睫状体肿瘤的MRI诊断

目的 研究眼部睫状体肿瘤的ＭＲＩ表现,并探讨其在诊断和鉴别诊断中的价值。方法 总结分析１１例经手术病理证实的睫状体肿瘤的ＭＲＩ表现。结果 黑色素瘤６例,与脑实质信号相比为短Ｔ１、短Ｔ２信号,５例增强扫描显示中度至明显强化;神经瘤３例,Ｔ１ＷＩ为等信号,Ｔ２ＷＩ为高信号,增强后明显均匀强化;睫状体色素上皮腺瘤１例,呈短Ｔ１、短Ｔ２信号,增强后明显强化;黑色素细胞瘤１例,呈短Ｔ１、短Ｔ２信号,增强后无     

Uveal melanoma incidentally diagnosed with neuroimaging,a case series of 3 patients

Uveal melanoma is the most common primary intraocular malignancy and can occur in the choroid, the ciliary body, or the iris. It is most often diagnosed based on clinical examination by an ophthalmologist. Nearly all patients present with visual symptoms. Characteristic findings on clinical examination include pigmented or pale choroidal masses with serous retinal detachments and acoustic hollowness seen with ocular ultrasonography. CT and MRI of the orbits are not traditionally utilized for the diagnosis of uveal melanoma. We present 3 cases in which uveal melanoma was an incidental finding on neuroimaging for unrelated conditions in asymptomatic patients. Radiologists should maintain a high suspicion for uveal melanoma when an intraocular mass of greater than 2 mm in thickness is seen on CT or MRI.