不同弥散梯度模式对前列腺DWI成像质量的影响

Effects of Different Diffusion Gradient Patterns on DWI Quality of Prostate

目的对比3种不同弥散梯度模式下MR扩散加权成像(DWI)的图像质量,探讨最佳的弥散梯度模式。方法采用ALL、3in1、Tetra三种不同弥散梯度模式,前瞻性进行37例前列腺DWI检查,均采用小视野(b值50、800 s/mm^2),根据前列腺DWI图外周带有无高信号结节分为正常组(A组)和病变组(B组),分别对三种模式两组图像进行主观评分,并分别比较信噪比(SNR)、对比噪声比(CNR)和ADC值。结果前列腺正常组20例,病变组17例。A、B两组Tetra模式的SNR和CNR均显著高于3in1模式和ALL模式(P<0.05);正常组ALL模式SNR和CNR高于3in1模式,差异有统计学意义(P<0.05);病变组ALL模式SNR和CNR与3in1模式相当,差异无统计学意义(P>0.05)。Tetra模式图像主观评分显著高于其他两种模式(P<0.05);3in1模式评分低于ALL模式,但差异无统计学意义(P>0.05);三种模式ADC值无显著差异(P>0.05)。结论 Tetra模式是前列腺DWI成像较佳的弥散梯度模式。

Objective To discuss the best diffusion gradient mode of the diffusion-weighted imaging（DWI） in prostate imaging by comparing the image quality of DWI in different diffusion gradient models.Methods 37 cases of patients underwent prostate imaging with different diffusion gradient modes（ALL,3 in1,Tetra） and the same small view DWI imaging（b value 50,800 s/mm^2） and other similar parameters for an MRI scan by prospective studies.These cases were divided into normal group A and abnormal group B,according to the presence（A） or absence（B） of high signal nodules in prostate＇s peripheral zone.A contrast of subjective ratings of the three patterns of A and B group was also done,including signal to noise ratio（SNR）,contrast noise ratio（CNR） and ADC values.Statistical analysis was then done.Results There were 20 cases of normal prostate in group A and 17 cases of abnormal prostate in group B.SNR and CNR of three models in group A and group B had significant difference（P〈0.05）,and in these two groups,SNR and CNR of Tetra models were higher than 3-in-1 models and ALL models.Compared with both,two were significant（P〈0.05）.SNR and CNR of ALL model were significant（P〈0.05）,higher than 3in1 model in group A,but had no significant difference in group B（P〈0.05）.Tetra pattern of image score was significantly（P〈0.05） highest than the other two sequences,and 3in1 modes score was not significantly（P〈0.05） lower than ALL modes.The ADC values in the interested area of three models were quite similar,had no significant difference（P〉0.05）.Conclusion Tetra mode is the best diffusion gradient mode in prostate DWI image.