MR动态减影血管造影在脑动静脉畸形治疗前后中的评价

目的评价MR动态减影血管造影（MR-DSA）在脑动静脉畸形（AVM）栓塞治疗前后的价值和限度。方法22例AVM患者，在栓塞前后均行MR—DSA、三维增强MR血管造影（3D—CEMRA）、MR质子加权成像（PWI）和DSA检查，同时由2名有经验的医生独立进行双盲对照研究。结果MR-DSA和DSA在22例AVM栓塞前后的瘤巢大小及分类上结果一致，MR—DSA能够显示AVM栓塞后的血液动力学改变，瘤巢及引流静脉显影推迟17例，瘤巢变小13例（其中完全消失4例），与DSA符合率为100％。与DSA相比，MR-DSA没有显示瘤巢内动脉瘤和栓塞后引流静脉及供血动脉直径变小各1例，而3D-CEMRA对此显示清晰。栓塞后的PWI与栓塞前相比，22例均可见不同程度的高信号。结论MR—DSA是1种快速、有效、无创的血管造影检查方法，能提供AVM栓塞前后的血流动力学信息，MR—DSA、3D-CEMRA和PWI应在AVM的随访中相互结合，综合运用。

Evaluation of intracranial arteriovenous malformations before and after embolization with dynamic MR digital subtraction angiography

Objective To evaluate the clinical utility and accuracy of dynamic MR digital subtraction angiography(MR-DSA) in the detection of intracranial arteriovenous malformations before and after embolization. Methods A prospective blinded comparison of MR-DSA, 3D contrast-enhanced T_1-weighted MR angiography(3D-CEMRA), proton-weighted imaging and conventional digital subtraction angiography(DSA) were underwent in 22 consecutive AVMs patients before and after embolization. Two readers independently interpreted images and compared with DSA images. Results There was complete agreement between MR-DSA and DSA for classification and size of nidus before and after embolization in all cases. MR-DSA showed the modified hemodynamic features(the time of nidus, early venous enhancement delayed after carotid arteries appearance) in 17 cases, and nidus size were reduced in 13 cases (including 4 complete embolized cases) after embolization, which were 100% consistence compared with DSA. MR-DSA failed to depict 1 intranidal aneurysm and missed 1 less dilated artery and draining vein after embolization respectively, which were demonstrated clearly by 3D-CEMRA confirmed with DSA. The relatively more or less hyperintensity could be seen on proton-weighted imaging in all cases after embolization than before. Conclusion MR-DSA is a fast, efficient, and noninvasive technique to provide hemodynamic information relevant for AVMs before and after embolization. Proton imaging is sensitive in delineation of the embolized region, MR-DSA, 3D-CEMRA and proton-weighted imaging should be combined in the evaluation and follow-up AVMs after partial embolization.