【作者】 鲜军舫；

【导师】 张云亭；

【作者基本信息】 天津医科大学 ， 影像医学与核医学， 2009， 博士

【摘要】 影像学不仅能帮助明确眼眶肿瘤和肿瘤样病变的诊断,而且是制定治疗方案和手术设计的主要依据,在诊治中发挥着非常重要且不可替代的作用。尽管如此,但部分眼眶肿瘤和肿瘤样病变术前诊断和鉴别诊断仍较困难。本研究目的是探讨磁共振成像（MRI）平扫结合静态增强和动态增强扫描在眼眶肿瘤和肿瘤样病变诊断和鉴别诊断中的价值,共分三部分。一、磁共振成像评估成人眼眶肿块良恶性的研究目的:前瞻性研究MRI平扫结合静态增强和动态增强扫描鉴别眼眶良恶性肿瘤和肿瘤样病变的价值,并评估哪些MRI表现是预测眼眶恶性病变的最可能因素及两观察者间的一致性。材料和方法:102例不易鉴别良恶性的成人眼眶软组织病变患者（男性患者51例,平均年龄46岁;女性患者51例,平均年龄54岁）行MRI平扫、静态增强扫描和动态增强扫描。所有病变均为病理组织学证实。对照病理组织学结果评价眼眶良恶性肿瘤和肿瘤样病变MRI表现,并采用多元logistic回归分析评价预测眼眶恶性病变的最可能表现。前瞻性评估MRI平扫、MRI平扫结合静态增强以及MRI平扫结合静态增强和动态增强扫描三种模式主观性诊断眼眶良恶性病变的灵敏度和特异度。结果:60例为良性病变,42例为恶性病变。对两个观察者来说,肌锥外间隙和眶隔前间隙受累、形态、边界、病变包绕眼球或其他结构、T₁WI信号均匀度、T₂WI信号强度、T₂WI信号均匀度、强化方式和动态增强曲线（TIC）呈流出型等在眼眶良恶性病变之间有显著性差异（p<0. 05）。多元logistic回归分析结果显示:对两观察者,预测眼眶恶性病变的最可能表现是T2WI呈等信号和TIC类型呈流出型。多元logistic回归分析结果显示MRI平扫结合静态增强和动态增强扫描预测眼眶恶性病变的灵敏度和特异度分别为83. 3%和88. 3%,明显优于MRI平扫（灵敏度和特异度分别为78. 6%和86.7%）或MRI平扫结合静态增强扫描（灵敏度和特异度分别为78.6%和88.3%） （p<0.05）。采用五点可信区间分级法（five-point confidence rating scale）主观性诊断眼眶良恶性病变,MRI平扫结合静态增强和动态增强扫描的灵敏度和特异度分别为97. 6%和71. 7%,明显高于MRI平扫（灵敏度和特异度分别为81%和58.3%）或MRI平扫结合静态增强扫描（灵敏度和特异度分别为81%和58.3%） （p<0.05）。结论:MRI平扫结合静态增强和动态增强扫描明显提高了鉴别成人眼眶良恶性肿瘤和肿瘤样病变的能力。边界不清楚的不规则肿块、病变包绕眼球、T₂WI呈等信号或TIC类型呈流出型提示为恶性病变,而边界清楚的规则肿块、T₂WI呈低信号、强化方式呈周边强化或TIC类型呈持续强化型常提示为良性病变。二、磁共振成像鉴别眼眶海绵状血管瘤和神经鞘瘤的价值目的:比较分析眼眶海绵状血管瘤和神经鞘瘤MRI表现,评价能帮助鉴别二者的MRI特征。材料和方法:2004年6月到2009年1月病理组织学证实的43例眼眶海绵状血管瘤和16例眼眶神经鞘瘤分别行MRI平扫、静态增强扫描和动态增强扫描,回顾性比较分析二者的MRI表现。结果:病变部位、形态、眼球壁受压变平、T₁WI信号及均匀度、T₂WI信号及均匀度、增强起始时强化范围、全时相强化方式、TIC类型、CI值等在眼眶海绵状血管瘤和神经鞘瘤之间有显著性差异（p<0. 05）。结论:眼眶海绵状血管瘤和神经鞘瘤MRI表现不同,有助于鉴别诊断。海绵状血管瘤增强起始时表现为点片状强化以及“渐进性强化”是鉴别二者的最可靠表现。三、眼眶海绵状淋巴管瘤磁共振成像表现目的:总结分析眼眶海绵状淋巴管瘤MRI表现。方法:回顾性分析34例（男4例,女30例,年龄范围为26岁到66岁,平均年龄为45岁）病理诊断为眼眶海绵状淋巴管瘤的MRI表现,并与对照组海绵状血管瘤比较。结果:17例（50%）眼眶海绵状淋巴管瘤发生于左侧,17例（50%）发生于右侧;20例（58.8%）位于肌锥内间隙,14例（41. 2%）位于肌锥外间隙; 25例（73.5%）位于眼眶前部,6例（17. 7%）位于眼眶后部,3例（8.8%）眼眶前、后部均受累;31例（91.2%）呈椭圆形,3例（8.8%）呈圆形;34例（100%）呈等T1长T2信号;32例（94. 1%）呈渐进性强化,2例（5. 9%）不均匀强化;24例（70. 6%）TIC呈流出型,8例（23. 5%）呈平台型,2例（5. 9%）呈持续强化型。与海绵状血管瘤相比,眼眶海绵状淋巴管瘤发生在肌锥外间隙较多（p=0. 03）,更常发生于女性（p=0. 03）。结论:眼眶海绵状淋巴管瘤与海绵状血管瘤MRI表现极相似,很难鉴别。如果眼眶内椭圆形或圆形肿块呈等T₁长T₂信号并有“渐进性强化”表现,在诊断和鉴别诊断时需考虑海绵状淋巴管瘤。更多还原

【Abstract】 Imaging plays a vital role in the diagnosis and management of orbital neoplasmsand simulating lesions because it provides adequate information for the diagnosis andnecessary evidences for the treatment planning of orbital lesions.However,it can bedifficult to diagnose and differentially diagnose some orbital neoplasms andsimulating lesions.Therefore,our aim is to evaluate the value of static and dynamicgadopentetate dimeglumine-enhanced magnetic resonance （MR）imaging combinedwith nonenhanced MR imaging in the diagnosis and differential diagnosis of orbitalneoplasms and simulating lesions.The study is composed of three parts.Part 1 Orbital Masses in Adult Patients:Value of MagneticResonance Imaging in Prediction of MalignancyObjective:To prospectively evaluate static and dynamic gadopentetatedimeglumine-enhanced magnetic resonance （MR）imaging combined withnonenhanced MR imaging in differentiation of benign from malignant soft-tissuelesions in the orbit and to evaluate which MR imaging parameters are most predictiveof malignancy.Materials and methods:One hundred and two consecutive adult patients including51 male patients with mean age of 46 years and 51 female patients with mean age of54 years with a soft-tissue mass in the orbit underwent nonenhanced,static anddynamic gadopentetate dimeglumine-enhanced MR imaging.Diagnosis was based onhistologic findings in surgical specimens.The sensitivity and specificity of threemodels were compared,including combination of nonenhanced MR imaging,staticand dynamic enhancement MR imaging,combination of nonenhanced MR imagingand static enhancement MR imaging,and nonenhanced MR imaging alone.MRimaging parameters of benign and malignant soft-tissue lesions in the orbit wereevaluated correlated with histologic findings.Multivariate logistic regression analysiswas used to identify the best combination of MR imaging parameters that might bepredictive of malignancy.For subjective MR imaging diagnosis obtained withfive-point confidence rating scale,the sensitivity and specificity of combination ofnonenhanced MR imaging,static and dynamic enhancement MR imaging, combination of nonenhanced MR imaging and static enhancement MR imaging,andnonenhanced MR imaging alone were prospectively evaluated.Results:Benign lesions were demonstrated in 60 patients,and malignant lesions in42 patients.For both observers,location,shape,and margin of the lesion,moldingorbital structures,homogeneity on T₁-weighted imaging,signal intensity onT₂-weighted imaging,homogeneity on T₂-weighted imaging,pattern of enhancement,and a washout type time-signal intensity curve （TIC）were significantly differentbetween benign lesions and malignant lesions （p＜0.05）.Multivariate logisticregression analysis identified the most discriminating MR imaging parameters wereisointensity on T₂-weighted imaging and a washout type TIC for both observers.Multivariate logistic regression analysis also revealed combination of nonenhancedMR imaging,static and dynamic enhancement MR imaging in prediction ofmalignancy with a sensitivity of 83.3% and a specificity of 88.3%,was significantlysuperior to nonenhanced MR imaging parameters combined with staticcontrast-enhanced MR imaging with a sensitivity of 78.6% and a specificity of 88.3%,and to nonenhanced MR imaging alone with a sensitivity of 78.6% and a specificityof 86.7%.For subjective MR imaging diagnosis obtained with five-point confidencerating scale,sensitivity and specificity of combination of nonenhanced MR imaging,static and dynamic enhancement MR imaging being 97.6% and 71.7%,respectively,were significantly higher than those of nonenhanced MR imaging parameterscombined with static contrast-enhanced MR imaging （sensitivity and specificity was81% and 58.3%,respectively）,and nonenhanced MR imaging alone（sensitivity andspecificity was 81% and 58.3%,respectively）（p＜0.05）.Conelusion:Static and dynamic gadopentetate dimeglumine--enhanced MR imagingcombined with nonenhanced MR imaging improved differentiation between benignand malignant neoplasms and simulation lesions in the orbit in adult patients.Anirregularly ill-defined mass,molding around orbital structures,isointensity onT₂-weighted imaging,or a washout type TIC was suggestive of malignant lesions,whereas a regularly well-defined mass,hypointensity on T₂-weighted imaging,peripheral enhancement,or persistent type TIC was indicative of benign lesions.Part two Value of Magnetic Resonance Imaging in the Differentiation of Orbital Cavernous Hemangiomas andSchwannomasObjective:To compare magnetic resonance （MR）imaging features of orbitalcavernous hemangiomas and schwannomas and evaluate MR imaging features in thedifferential diagnosis of the two lesions.Materials and methods:Nonenhanced,static and dynamic gadopentetatedimeglumine-enhanced MR imaging scanning was performed in forty-three patientswith orbital cavernous hemangiomas and sixteen patients with orbital schwannomasconfirmed by pathology from June of 2004 to January of 2009.MR imaging findingsof orbital cavernous hemangiomas and schwannomas were analysed retrospectivelyand compared.Results:There was significant difference between orbital cavernoushemangiomas and schwannomas in several MRI features including location,shape,signal intensity and homogeneity on T₁-weighted and T₂-weighted images,initialenhancement extent and enhancement pattern after contrast administration,time-signal intensity curve type,and relative contrast index of the lesion （p＜0.05）.Conclusion:MR imaging features of orbital cavernous hemangiomas andschwannomas were different,which might contribute to differentiation of them.Enhancement of one point,two points or one portion in the early phase after contrastadministration and progressive filling of contrast media into the lesion could bereliable features in distinguishing between them.Part three Magnetic Resonance Imaging Findings of CavernousLymphangiomas in the OrbitObjective:MR imaging findings of cavernous lymphangiomas in the orbit wereevaluated.Methods:MR imaging findings including dynamic enhancement MR imagingscanning in 34 cases consisting of 30 females and 4 males with cavernouslymphangiomas in the orbit confirmed by histopathology were analyzedretrospectively.MR imaging findings of cavernous lymphangiomas were comparedwith those of cavernous hemangiomas as control.Results:Cavernous lymphangiomas were identified in the left orbit in 17 cases （50%） and in the right orbit in 17 cases （50%）.A mass was observed in the intraconal spacein 20 cases （58.8%）and in the extraconal space in 14 cases （41.2%）.The anteriororbit was involved in 25 cases （73.5%）,the posterior orbit in 6 cases （17.7%）,andboth the anterior orbit and posterior orbit in 3 cases （8.8%）.MRI revealed an ovoidmass in 31 cases （91.2%）and a round mass in 3 cases （8.8%）.The mass wasisointense on T₁WI and hyperintense on T₂WI in 34 cases （100%）.Thirty-twopatients （94.1%）showed“progressive enhancement”pattern and two patients （5.9%）showed inhomogeneous enhancement on dynamic contrast enhancement MR imagingscanning.The time-signal intensity curve in 24 patients （70.6%）was characterized asa washout curve,the time-signal intensity curve in 8 patients （23.5%）wascharacterized as a plateau-shaped curve,and the time-signal intensity curve in 2patients （5.9%）was characterized as persistent.Compared with cavernoushemangiomas,cavernous lymphangiomas more frequently located in the extraconalspace （p=0.03）and occurred in female patients （p=0.03）.Conclusion:MR imaging findings of orbital cavemous lymphangiomas are sosimilar to those of cavemous hemangiomas that it is difficult to differentiate thempreoperatively.However,cavernous lymphangioma should be included in the list ofthe diagnosis and differential diagnosis of an ovoid mass in the orbit demonstratingidentical T₁ and long T₂ signal intensity and‘progressive enhancement’on dynamicenhancement MR imaging scanning.更多还原