耳源性乙状窦血栓性静脉炎CT及MRI表现

CT and MRI findings of otogenic sigmoid sinus thrombophlebitis

目的探讨中耳乳突炎引起的乙状窦血栓性静脉炎及周围脓肿的特征性影像征象。方法回顾分析11例中耳乳突炎导致的乙状窦血栓性静脉炎的影像学表现。11例患者均行颞骨高分辨CT检查和MRI平扫及增强,5例行磁共振静脉血管成像(magnetic resonance venography,MRV)检查,4例行颅脑CT检查。结果 CT主要表现为10例乙状窦前壁骨质明显破坏,1例无明显破坏;4例乙状窦内或周围有积气,手术证实3例为乙状窦脓肿和周围脓肿,1例为单纯乙状窦周围脓肿。MRI表现为11例患者以乙状窦为中心的侧窦系统流空信号均消失,窦壁增厚有强化;T1WI表现为等信号6例、略低信号2例、稍高信号3例,T1WI增强可见窦壁增厚强化、腔内软组织影不同程度强化;T2WI均为高信号。5例MRV均显示患侧乙状窦和颈内静脉充盈缺损;2例横窦亦见充盈缺损,3例横窦局部变细。结合MRI和MRV检查,11例病变均累及乙状窦,同时累及颈静脉球及颈静脉上段,有9例同时累及横窦。结论 CT所显示的乙状窦前壁骨质缺损高度提示乙状窦血栓性静脉炎的可能性,窦周围或窦内积气提示乙状窦周围脓肿或窦内脓肿。MRI和MRV可准确显示乙状窦血栓位置和周围结构受累情况,也可推测血栓的成份。

OBJECTIVE To explor e the CT and MRI appearances of otogenic sigmoid sinus thrombophlebitis（SST） and abscess. METHODS The HRCT, plain MRI,magnetic resonance venography（MRV）,enhanced MRI findings in 11 patients with otogenic SST were retrospectively analyzed. RESULTS On CT, the bony wall of sigmoid sinus was eroded in 10 cases（10/11）,and air bubbles were found in or around sigmoid sinus in 4 cases. On plain MRI, sigmoid sinus flow void effect disappeared in all 11 cases. SST manifested as high signal on T2WI in all 11 cases, and as low signal on T1WI in 2 cases,isointense signal on T1WI in 6 cases, high signal on T1WI in3 cases. Contrast enhancement MRI showed enhancement in wall of venous sinus,but venous sinus thrombosis did not enhanced,but showed as irregular filling defect or empty triangle. MRV showed that involved venous sinus was not visualized. CONCLUSION CT can show the erosion of the bony wall of sigmoid sinus which may indicate the SST;and if air bubbles are found around or in the sigmoid sinus,the abscess around or in the sigmoid sinus should be doubted.Conventional MRI combined with MRV are effective and noninvasive methods in the diagnosis of SST.