摘要
目的:选择直肠癌3.0T磁共振扩散加权成像(DWI)的合适b值,以利于DWI对直肠癌病灶的检出。方法:对63例直肠癌患者行多b值DWI检查(b值为300、600、900、1200、1500、1800、2100s/mm2)及常规MRI平扫(T2WI、T1WI)。测量不同b值时直肠癌的ADC值;计算直肠癌的信噪比(SNR)及膀胱的信号强度比(SIR);根据HE染色病理图片记录直肠癌的细胞密度,并进行统计学分析。结果:随着b值的增大,直肠癌ADC值及SNR呈逐渐降低趋势,差异有统计学意义(P<0.05)。当b值≤1200s/mm2时,DWI图像中直肠癌SNR均高于T2WI图像(P<0.05)。各不同b值的DWI图像中膀胱SIR均低于T2WI图像(P<0.05),随着b值的增大膀胱SIR逐渐减低,当b值≥1200s/mm2时,膀胱SIR明显减低接近于1。不同b值时直肠癌ADC值与细胞密度之间均呈负相关(P<0.05),b=1200s/mm2时,其相关度最高(r=-0.76,P<0.05)。结论:直肠癌3.0T磁共振扩散加权成像中的合适b值应为1200s/mm2。
Objective：To select an appropriate b value on diffusion weighted imaging （DWI） in rectal cancer patients using a 3.0T MR scanner,in order to facilitate the detection of rectal cancer loci. Methods： Sixty-three patients with rectal cancer underwent multi b-value DWI （b value = 300,600,900, 1200, 1500,1800,2100s/mm^2 ） and routine MR scanning （T2 WI,T1 WI）. The ADC values of rectal cancer at different b values were measured, and the signal noise ratio （SNR） of rectal cancer and signal-intensity ratio （SIR） of bladder were calculated. The cell density of rectal cancer was recorded according to hematoxylin and eosin （HE） staining. Results：The ADC value and SNR of rectal cancer decreased gradually with the increasing of b value,with significant statistic difference （P〈0.05）. The SNR of rectal cancer on DWI was higher than that on T2WI when b value was ≤1200s/mm^2. The SIR of bladder on DWI with different b values was lower than that on T2WI （P〈0.05）. The SIR of bladder decreased gradually with the increasing of b value, The SIR was markedly reduced and close to 1 when b value was ≥1200s/mm^2 （P〈0.05）. The ADC values with different b values had negative correlation with the cell density of rectal cancer （P〈0.05 ,when h value was equal to 1200s/mm^2 ,the correlation was the highest （r=-0.76, P〈0.05）. Conclusion：Using a 3.0T magnetic resonance scanner for the examination of rectal cancer, the appropriate b value is 1200s/mm^2 on DWI.
出处
《放射学实践》
北大核心
2016年第9期874-877,共4页
Radiologic Practice
关键词
直肠肿瘤
扩散加权成像
磁共振成像
B值
Rectal neoplasms
Diffusion weighted imaging
Magnetic resonance imaging
b value
