目的探索回波平面成像校正(EPIC)序列对颈髓扩散加权成像(DWI)及扩散张量成像(DTI)图像质量的改善价值。方法2022年1月至3月招募志愿者33名,采用3.0 T MR行矢状面T1WI,校正前后DWI、DTI序列扫描。两名观察者在T1WI与校正前后DWI、DTI序...目的探索回波平面成像校正(EPIC)序列对颈髓扩散加权成像(DWI)及扩散张量成像(DTI)图像质量的改善价值。方法2022年1月至3月招募志愿者33名,采用3.0 T MR行矢状面T1WI,校正前后DWI、DTI序列扫描。两名观察者在T1WI与校正前后DWI、DTI序列融合图像上勾画ROI测量表观扩散系数(ADC)值、各向异性分数(FA)值,测量偏移距离,并对图像质量进行5分法主观评分。采用组内相关系数(ICC)、Kappa检验对两名观察者测量数据和主观评分的一致性进行评价。采用配对样本t检验和Wilcoxon秩和检验比较校正前后图像定量值的差异,采用Mann-Whitney U检验比较校正前后图像主观评分的差异。结果两名观察者测量数据和主观评分一致性良好(ICC为0.912~0.999,Kappa为0.778~0.816)。校正前后DWI序列所测C6 ADC值,C4、C5、C6脊髓的偏移距离和主观评分差异均有统计学意义(P<0.05);校正前后DTI序列C1、C3脊髓的FA值,C1、C3脊髓的ADC值,C4、C5、C6脊髓的偏移距离和主观评分差异均有统计学意义(P<0.001)。结论EPIC序列可以显著降低图像畸变,改善图像质量。展开更多
The radar echo signal of non-stationary and singular points usually contains false echoes,which affects the recognition and measurement of liquid level echo signal.In order to eliminate false echo interference and imp...The radar echo signal of non-stationary and singular points usually contains false echoes,which affects the recognition and measurement of liquid level echo signal.In order to eliminate false echo interference and improve the recognition and measurement accuracy of the liquid level gauge,a method of echo recognition and correction based on adaptive least mean square(LMS)is proposed.The short-time amplitude function and short-time zero crossing rate function are combined to recognize the echo signal.The weight vector iteration and updating weight coefficients are obtained by LMS method.The echo signal is recognized and the false echo interference is suppressed.The experimental results show that the level echo signal can be accurately recognized by this method,and level measurement accuracy can reach0.47%F.S.Compared with other denoising methods,adaptive LMS can keep the signal singularity characteristics while suppressing the noise.Moreover,it has better robustness.展开更多
文摘目的探索回波平面成像校正(EPIC)序列对颈髓扩散加权成像(DWI)及扩散张量成像(DTI)图像质量的改善价值。方法2022年1月至3月招募志愿者33名,采用3.0 T MR行矢状面T1WI,校正前后DWI、DTI序列扫描。两名观察者在T1WI与校正前后DWI、DTI序列融合图像上勾画ROI测量表观扩散系数(ADC)值、各向异性分数(FA)值,测量偏移距离,并对图像质量进行5分法主观评分。采用组内相关系数(ICC)、Kappa检验对两名观察者测量数据和主观评分的一致性进行评价。采用配对样本t检验和Wilcoxon秩和检验比较校正前后图像定量值的差异,采用Mann-Whitney U检验比较校正前后图像主观评分的差异。结果两名观察者测量数据和主观评分一致性良好(ICC为0.912~0.999,Kappa为0.778~0.816)。校正前后DWI序列所测C6 ADC值,C4、C5、C6脊髓的偏移距离和主观评分差异均有统计学意义(P<0.05);校正前后DTI序列C1、C3脊髓的FA值,C1、C3脊髓的ADC值,C4、C5、C6脊髓的偏移距离和主观评分差异均有统计学意义(P<0.001)。结论EPIC序列可以显著降低图像畸变,改善图像质量。
基金National Natural Science Foundation of China(No.61261029)
文摘The radar echo signal of non-stationary and singular points usually contains false echoes,which affects the recognition and measurement of liquid level echo signal.In order to eliminate false echo interference and improve the recognition and measurement accuracy of the liquid level gauge,a method of echo recognition and correction based on adaptive least mean square(LMS)is proposed.The short-time amplitude function and short-time zero crossing rate function are combined to recognize the echo signal.The weight vector iteration and updating weight coefficients are obtained by LMS method.The echo signal is recognized and the false echo interference is suppressed.The experimental results show that the level echo signal can be accurately recognized by this method,and level measurement accuracy can reach0.47%F.S.Compared with other denoising methods,adaptive LMS can keep the signal singularity characteristics while suppressing the noise.Moreover,it has better robustness.
