扩散加权成像在急性脑梗死消除金属假牙伪影中的应用

目的研究并行采集（SENSE）技术联合平面回波扩散加权像（EPI—DWI）技术在具有磁化率伪影的脑梗死中的应用。方法收集38例装有固定金属假牙脑梗死的患者资料，其中男性22例，女性16例：年龄52～86岁。平均年龄72岁。均行MRI头颅平扫、弥散加权成像（DWI）与SENSE—EPI—DWI。比较分析使用SENSE技术前后的右侧基底节区与右侧侧脑室脑脊液两者的信号强度对比度（SIR）（均数±标准差）、对比噪声比（CNR）、SIR、正常小脑表面扩散系数（ADC）值、梗死灶／健侧脑组织的ADC比值。结果①SENSE—EPI-DWI的右侧基底节区与右侧侧脑室脑脊液两者的SIR的均数士标准差高于常规EPI—DWI的序列（0．8100±0．3863vs0．6100±0．4687：t=9．872，P〈0．05）；@SENSE—EPI—DWI的CNR均高于常规EPI—DWI的CNR（11．6225vs4．3853；t=6．615，P〈0．05）；③SENSE—EPI—DWI的SIR均低于常规EPI—DWI的SIR（1．1332vs1．1586：t=-2．870．P〉0．05）：④SENSE—EPI—DWI的正常小脑ADC值均高于常规EPI—DWI序列的正常小脑ADC值（t=9．962，P〈0．05）：⑤SENSE—EPI—DWI的梗死灶，健侧脑组织的比值均高于常规EPI-DWI的梗死灶，健侧脑组织的比值（1．34vs1．06：t=5．216，P〈0．05）。结论SENSE—EPI-DWI技术的成像质量较高，正常小脑ADC值有助于脑梗死的诊断．且在具有磁化率伪影的脑梗死诊断应用中优于常规的EPI—DWI序列。

Diffusion-weighted imaging for eliminating metal denture artifacts in acute cerebral infarction diagnosis

Objective To investigate the diagnostic value of parallel acquisition(SENSE) combined with echo-planar diffusion-weighted imaging(EPI-DWI) in cerebral infarction with magnetic susceptibility artifacts.Methods A total of 38 cerebral infarction patients with metal dentures were enrolled,male 22,female 16,aged 52-86 years old,mean age 72 years old.All of them received MRI,DWI and SENSE-EPI-DWI.The mean standard deviation,contrast to noise ratio(CNR),signal intensity contrast ratio(SIR),apparent diffusion coefficient(ADC) values of normal cerebella and infarct/contra lateral ratio of brain tissue between right basal ganglia and right lateral ventricle cerebrospinal fluid signal before and after analysis of SENSE were compared.Results ①SENSE-EPI-DWI sequence of mean standard deviation in right basal ganglia and right lateral ventricle cerebrospinal fluid signal intensity contrast was higher than that of conventional EPI-DWI sequence(0.810 0 ± 0.386 3 vs 0.610 0 ± 0.468 7;t = 9.872,P < 0.05).②SENSE-EPI-DWI sequence of CNR were higher than that of conventional EPI-DWI sequence(11.622 5 vs 4.385 3;t = 6.615,P < 0.05).③SENSE-EPI-DWI sequence of SIR was lower than that of conventional EPI-DWI sequence(1.133 2 vs 1.158 6;t =-2.870,P > 0.05).④SENSE-EPI-DWI sequence of ADC values were higher than those of conventional EPI-DWI sequence(t = 9.962,P < 0.05).⑤SENSE-EPI-DWI sequence of infarct/contra lateral ratio of brain tissue were higher than those of conventional EPI-DWI sequence(1.34 vs 1.06;t = 5.216,P < 0.05).Conclusion It is demonstrated that the technology could obtain high quality images and the ADC values of normal cerebella contribute to the diagnosis of cerebral infarction.SENSE-EPI-DWI is better than conventional application of EPI-DWI sequence in diagnosis of cerebral infarction with magnetic susceptibility artifacts.