低场MRI扩散加权成像在超急性期脑梗死诊断中的临床应用

The clinical application of diffusion-weighted MR of low field in the diagnosis of hyperacute cerebral infarction

目的评估低场MRI扩散加权（DWI）在超急性脑梗死诊断中的应用价值。方法对临床高度怀疑超急性脑梗死且发病时间在6h以内的15例患者行0．35T磁共振常规MRI和DWI扫描。回顾性分析常规MRI、DWI诊断和最终临床诊断的相符性，比较DWI、ADC和常规MRI对超急性脑梗死诊断的敏感性和特异性。结果DWI诊断为超急性脑梗死12例，最终临床诊断为超急性脑梗死。DWI阴性3例，最终临床诊断为短暂性脑缺血发作。DWI所见高信号区域在CT／MRI随访中均有脑梗死灶。DWI诊断超急性脑梗死的敏感性和特异性均为100％，常规MRI的敏感性为20％，特异性为100％；超急性脑梗死区DWI呈明亮高信号，ADC图呈低信号。结论低场DWI结合ADC图可作为诊断超急性脑梗死的一项重要指标，其诊断准确性高，为临床科学地进行超早期溶栓治疗提供了客观依据。

Objective To evaluate the clinical application of diffusion-weighted MR of low field in hyperacute cerebral infarction. Methods Conventional MRI and DWI on 0.35T were performed in 15 patients with highly suspicious hyperacute infarction within 6 hours after presenting symptoms. The coincidence between conventional MRI ,DWI and final clinical diagnosis was analyzed to compare the sensitivity and specificity of diagnosis among DWI ,ADC and conventional MRI. Results 12 patients were diagnosed as hyperacute cerebral infarction, identical with final clinical diagnosis. 3 patients were negative on DWI, who were finally diagnosed as TIA by clinical doctors. The high-intensity zone on DWI appeared infarction in following CT or MRI examination. The sensitivity and specificity of DWI were both 100 %, and those of conventional MRI was 20 % and 100 %, respectively. The infarctional region on DWI appeared high intensity and it was in low intensity on ADC maps. Conclusion DWI combined with ADC maps can be an important index in the diagnosis of hyperacute cerebral infarction. Its accuracy for diagnosis was high, which provides objective proofs for early clinical thrombolysis treatment.