颅内静脉窦血栓形成的早期MRI诊断及病理基础

目的:研究颅内静脉窦血栓形成(CVST)的MR表现及其病理基础,旨在提高早期诊断水平.方法:回顾分析经临床和影像学方法确诊的11例CVST患者.MR检查技术包括平扫、增强扫描及MRV;其中4例行CT平扫检查;3例行DSA检查.结果:11例CVST累及上矢状窦5例,横窦1例,乙状窦1例,直窦1例,上矢状窦及横窦及乙状窦联合受累2例,横窦及乙状窦联合受累1例.CVST的直接征象:急性期血栓3例,T1 WI呈等信号或等高混杂信号,T2 WI呈低信号,周围可见稍高信号的环,为增厚的硬膜;亚急性期血栓8例,T1 WI及T2 WI均以高信号为主.增强扫描受累静脉窦可见空"三角"征或"充盈缺损"征.MRV可显示受累静脉窦不显影或者充盈缺损形成.CVST的继发脑损害包括脑肿胀、出血及梗死等.结论:磁共振检查对CVST的早期诊断具有重要价值.对于T2 WI呈低信号的急性期血栓,应仔细观察围是否有较高信号的环形改变,进一步行增强扫描结合MRV检查可作出早期准确的诊断.

Early MR Diagnosis of Cerebral Venous Sinus Thrombosis and Pathophysiological Changes

Objective:To study the MR findings of cerebral venous sinus thrombosis and pathophysiological changes for the early diagnosis.Methods:MR findings of 11 cases of dural sinus thrombosis diagnosed by clinic and imaging were reviewed retrospectively,including six women and five men,mean age 31 years.All cases were underwent non-enhanced MRI,enhanced MRI and MR venography.Additionaly,4 patients were performed CT and 3 were underwent DSA.Results:CVST involved superior sagittal sinus in 5 cases,transverse sinus 1,sigmoid sinus 1,straight sinus 1,superior sagittal sinus and transverse sinus and sigmoid sinus 2,transverse sinus and sigmoid sinus1.Direct signs of CVST:3 cases of acute thrombus showed isointensity or iso- to hyperintensity on T1WI and hypointensity on T2WI with a hyperintensity ring was surrounded with the thrombus, which is the thickening dura.8 cases of subacute thrombus showed hyperintensity on T1WI and T2WI.The involved sinuses were demonstrated "empty delta" sign or "filling defect" sign on enhanced MRI.MR venography displayed the loss of the normal flow signal,as nonvisulization or the filling defect sign in the involved cerebral venous sinuses.The secondary cerebral damages included cerebral swelling,infarct and hemorrhage.Conclusion:MR examination plays an important role in the early diagnosis of CVST.For the early diagnosis of acute thrombus showed hypointensity on T2WI,the sign of a hyperintensity ring around the hypointensity thrombus is very helpful,and the further enhanced MRI and MR venography can help the final diagnosis earlier.