眼眶炎性假瘤眶外侵犯的途径及影像学表现

Extending Routes and Radiological Features of Idiopathic Orbital Pseudotumor with Extraorbital Extension

目的探讨眼眶炎性假瘤眶外侵犯的途径及影像学特点。方法回顾性分析临床及影像学诊断为眼眶炎性假瘤眶外侵犯并经活检证实的9例患者MRI及CT表现。9例患者均进行了眼眶MRI检查,其中3例同时进行了增强CT扫描。结果 1例直接向前侵犯眶隔前软组织;其余8例向后蔓延者均通过眶上裂,其中1例同时经视神经管向后蔓延,另1例通过眶下裂蔓延。病变向后侵犯海绵窦6例,其中两例同侧海绵窦段颈内动脉被病变包绕并狭窄;单独或同时侵犯中颅窝7例;翼腭窝及颞下窝累及1例。眶外病变在T1WI上呈等信号,在T2WI上呈稍低或低信号,增强后有中等度至明显强化。3例增强CT显示眶外病变呈高密度,病变形态及范围分别与其MRI表现类似。结论眼眶炎性假瘤可以发生眶外蔓延,眶上裂是最常见的眶外蔓延途径,海绵窦及中颅窝是两个最常见的累及部位。MRI和CT对眼眶炎性假瘤眶外蔓延的诊断具有重要的价值。

Objective To approach imaging features of idiopathic orbital pseudotumor with extraorbital extension.Methods The MRI and CT findings of nine patients with idiopathic orbital pseudotumors showing extraorbital extension were reviewed retrospectively.All patients had clinical and radiological diagnosis and confirmed by biopsy and pathology.MR images were obtained for all 9 patients,3 in combination with a contrast-enhanced CT scan.Results One of 9 cases extended anteriorly to directly involve the preseptal soft tissues.In the remaining 8 cases,lesions extended posteriorly through the superior orbital fissure.Of these 8 cases,6 showed cavernous sinus involvement.Two of these cases revealed encasement and narrowing of the cavernous portion of the internal carotid artery.The retro-orbital extension was also seen in the middle cranial fossa（n=7）,and the pterygopalatine fossa and infratemporal fossa（n=1）.The extraorbital lesions had an intermediate signal on the T1-weighted images,low signal intensity on T2-weighted images,and showed strong uniform enhancement on the contrast-enhanced imaging.Contrast-enhanced CT studies demonstrated the extraorbital lesions as moderate to strongly enhancing lesions.They revealed radiological contours similar to their MR imaging studies.Conclusion It is important to note that idiopathic orbital pseudotumor can spread beyond the orbits.The superior orbital fissure is the most common route of extraorbital extension.The cavernous sinus and the middle cranial fossa are the two most common locations involved.MRI and CT play an important role in diagnosis and differential diagnosis of idiopathic orbital pseudotumor with extraorbital extension.