下肢深静脉血栓形成MR检查的临床价值

目的探讨下肢深静脉血栓形成磁共振血管成像（MRA）和下肢深静脉血栓磁共振直接成像（MRDTI）的临床价值。资料与方法对25例临床确诊为下肢深静脉血栓形成的患者进行MRA和MRDTI检查．MRA采用二维时间飞越法（2DTOF）；MRDTI选用SET1WI、FSET2WI、FAST（fourier acquired steady state，FAST）序列。其中23例行数字减影血管造影（DSA）检查，MRA与DSA进行对照分析。结果下肢深静脉血栓形成的MRA表现有：静脉充盈缺损（14例）、静脉闭塞和中断（8例）、静脉再通（3例）、侧支循环形成（25例）。以DSA为诊断标准，MRA诊断符合率为95．65％。下肢深静脉血栓形成MRDTI表现为：急性血栓（19例），血栓在SET1WI、FSET2WI和FAST序列上多为等信号或高信号，信号多不均匀，6例可见血管周围水肿；慢性血栓（6例），血栓在SET1WI、FSET2WI和FAST序列上多均为低或等信号。结论2DTOFMRA结合多种序列MRDTI的表现，诊断下肢深静脉血栓更准确,并可以为判断血栓新旧提供依据。

Evaluation of the Clinical Values of MR Imaging in Detection of Deep Vein Thrombosis in the Low Extremities

Objective To assess the clinical values of magnetic resonance angiograph(MRA)and magnetic resonance direct thrombus imaging(MRDTI)in detection of deep vein thrombosis in the low extremities.Materials and Methods 25 patients of deep vein thrombosis in the low extremities confirmed by clinic were performed with two dimensional time of flight magnetic resonance angiograph(2D TOF MRA)and magnetic resonance direct thrombus imaging(MRDTI).MRDTI sequence included spin echo sequence T1-weight image(SE T1WI),fast spine echo sequence T2-weighted image(FSE T2WI)and fourier acquired steady state sequence(FAST).The findings of MRA were compared with that of digital subtraction angiography(DSA).Results The MRA findings of deep vein thrombosis in the low extremities included venous filling defect(14 cases),occlusions and interruptions of veins(8 cases),venous recanlizations(3 cases),collateral veins(25 cases).When the results of DSA were regard as golden standard,the accuracy of MRA was 95.65%.On the MRDTI images,acute thrombi(19 cases)had inhomogenous iso or hyperintensity in T1WI,T2WI and FAST and chronic thrombi(6 cases)had hypo or isointensity in T1WI,T2WI and FAST.In 6 acute cases,edemas surrounding vessels were found.Conclusion 2D TOF MRA combined MRDTI are more accurate in diagnosis of deep vein thrombosis in the low extremities.MRDTI may be used to evaluate the age of thrombus.