脑静脉窦血栓的MR与CT诊断对比研究

Diagnosis of cerebral venous sinus thrombosis:MR versus CT

目的:为更有效地提高脑静脉窦血栓(CVST)形成诊断的准确率,文中探讨了磁共振成像(MRI)与多层螺旋CT扫描对CVST形成的诊断价值。方法:回顾分析经临床确诊12例CVST患者的影像学表现。3例患者行MRI平扫,9例MRI平扫加增强扫描;8例行磁共振静脉成像(MRV)检查。10例患者行CT平扫,2例平扫加增强扫描。4例患者行数字减影血管造影(DSA)检查。结果:12例CVST患者中,累及上矢状窦3例,横窦1例,乙状窦4例,直窦2例,上矢状窦及乙状窦联合受累2例。MRI检查时CVST的直接征象:急性期血栓2例,T1WI呈等信号或等高混杂信号,T2WI呈低信号,周围可见稍高信号环,为增厚的硬膜。亚急性期血栓患者9例,T1WI及T2WI均以高信号为主,增强扫描可见受累静脉窦呈空"△"征或"充盈缺损",在T2WI上静脉窦流空信号消失是其特异性的表现。慢性期患者1例,T1WI为等信号,T2WI为高信号。MRV可发现受累静脉窦不显影或充盈缺损形成。CVST的继发性脑损害包括脑肿胀、出血及梗死等。结论:MRI和MRV是诊断静脉窦血栓形成的有效手段,对CVST的诊断优于CT,可替代有创伤性的DSA检查。对于T2WI呈低信号的急性期血栓,应仔细观察周围是否有较高信号的环形改变,进一步行增强扫描并结合MRV可作出早期准确的诊断。

Objective ： This article aims at the evaluation of MRI and multislice CT findings in the diag- nosis of cerebral venous sinus thrombosis （CVST） for the purpose of improving the diagnostic accuracy. Methods： The images of 12 cases of clinically proved CVST were collected and analyzed retrospeetively, of whom 3 underwent plain and 9 both plain and enhanced MRI ; 8 received magnetic resonance veins im- aging （MRV） ; 10 underwent plain and 2 both plain and enhanced CT scanning; and 4 received digital subtraction angiograpby （DSA）. Results： Among the 12 CVST eases, the superior sagittal sinus was involved in 3, the transverse sinus in 1, the sigmoid sinus in 4, the straight sinus in 2, and both the su- perior sagittal and sigmoid sinus in the other 2. Based on the direct MRI signs of CVST, 2 eases of acute thrombus showed isointensity or iso-hyperintensity on T1WI and hypointensity on T2WI with a hyperinten- sity ring and thickened dura, and 9 cases of subacute thrombus exhibited hyperintense on T1WI and T2WI. Enhanced scanning revealed the sign of ＂ Zk＂ or ＂filling defect＂ in the involved sinuses, with the specific manifestation of flow signal disappearance in the venous sinuses on T2WI. One chronic case showed isointensity on T1WI and hypointensity or formation of the filling defect in the involved on T2WI. MRV displayed the loss of normal flow signals cerebral venous sinuses. The secondary cerebral damages of CVST included cerebral swelling, infarction and hemorrhage. Conclusion： MRI and MRV examina- tions, as very effective means in the diagnosis of CVST, are obviously superior to CT, and can replace in- vasive DSA. The sign of a hyperintensity ring around the hypointensity thrombus is very helpful for the early diagnosis of acute thrombus with hypointensity on T2WI.