磁敏感加权成像对脑梗死的诊断价值

Diagnostic value of susceptibility weighted imaging in cerebral infarction:report of 38 cases

目的探讨磁敏感加权成像(susceptibility weighted imaging,SWI)对脑梗死的诊断价值。方法搜集经临床及影像学检查证实的脑梗死患者38例,其中急性期15例,亚急性期17例,慢性期脑软化灶6例。所有患者均行常规T1WI、T2WI、T2FLAIR平扫、DWI及SWI扫描,其中25例行MRA检查。分析MRI图像特点。结果常规MRI检出脑梗死灶内出血5例18个出血灶,SWI检出脑梗死灶内出血11例62个出血灶,SWI对脑梗死灶内出血灶的检出率(28.9%,11/38)明显高于常规MRI序列(13.2%,5/38,P<0.05)。急性期15例脑梗死灶SWI图像均表现为等信号,亚急性期11例为等信号,6例为低信号,慢性期6例均为低信号,不同时期脑梗死灶SWI信号特点差异有统计学意义(P<0.05)。急性期15例脑梗死灶内小静脉明显减少,亚急性期9例脑梗死灶内小静脉减少,8例脑梗死灶内小静脉及邻近脑组织内血管较对侧增多扭曲,慢性期6例脑软化灶内均可见增粗迂曲血管影,不同时期脑梗死灶内静脉血管的显示差异有统计学意义(P<0.05)。MRA显示17例患者一侧大脑中动脉闭塞,SWI均显示闭塞大脑中动脉内的血栓。结论SWI在显示脑梗死并发出血、脑梗死后血管构建等方面优于常规MRI序列,和常规MRI序列结合对脑梗死的诊断更为准确、全面,有重要的临床应用价值。

Objective To investigate the diagnostic value of susceptibility weighted imaging（SWI） in cerebral infarction.Methods Thirty-eight patients with clinically or radiologically proved cerebral infarction were enrolled in this study,including 15 acute cerebral infarction and 17 subacute cerebral infarction cases and 6 chronic cerebral infarction cases with encephalomalacia.Conventional non-contrast sequences including T1WI,T2WI,T2 fluid attenuated inversion recovery（FLAIR）,diffusion weighted imaging（DWI） and SWI were performed in all patients,and 25 patients underwent magnetic resonance angiography（MRA）.Characteristics of these images were analyzed.Results Eighteen hemorrhagic lesions within infarction were detected in 5 patients by routine sequences,while SWI showed 62 hemorrhagic lesions within infarction in 11 patients（P0.05）.On SWI,acute cerebral infarction appeared isointensity in all 15 cases,subacute infarction displayed isointensity（11 cases） and hypointensity（6 cases）,and all chronic infarction（6 cases） demonstrated hypo-intensity.The intensity difference in different stages has statistical significance（P0.05）.SWI found reduced venula inside the infarcted areas in all 15 acute cases,and revealed reduced venula（9 cases） and increased and tortuous venula（8 cases） in subacute infarction when compared with the unaffected side.Thickened and tortuous vessels were seen in all 6 chronic cases.The visualization of venula inside lesions in different stages has statistical significance（P0.05）.MRA revealed one side middle cerebral artery occlusion in 17 patients,while SWI showed middle cerebral artery thrombi in all 17 cases.Conclusion SWI is much better in demonstrating post-infarction hemorrhage and vascular reconstruction than conventional MRI sequences,and their combination is more accurate in cerebral infarction diagnosis and has important clinical values.