MRI同时多层采集扩散加权成像技术在克罗恩病结肠病变中的应用

Application of MRI Simultaneous Multi-Slice Diffusion Weighted Imaging Technique in Colon Lesion with Crohn’s Disease

目的探讨MRI同时多层采集扩散加权成像技术(Simultaneous Multi-Slice Diffusion Weighted Imaging,SMS-DWI)在克罗恩病患者结肠病变显示中的应用。方法收集我院15例经临床确诊为克罗恩病存在结肠病变的患者资料,均行b值为50、500和1000 s/mm^(2)的SMS-DWI和常规DWI成像。由两名放射科医生测量SMS-DWI和常规DWI序列24处结肠病变肠段肠壁和竖脊肌的信号强度(Signal Intensity,SI)、病变表观扩散系数(Apparent Diffusion Coefficient,ADC)值,计算2个序列病变肠壁与竖脊肌的相对对比噪声比(Relative Contrast to Noise Ratio,rCNR),同时联合评估b值为500、1000s/mm^(2)时SMS-DWI和常规DWI序列的图像总体质量和病灶显著度。采用配对样本t检验或Wilcoxon秩和检验比较SMSDWI和常规DWI序列病变肠壁与肌肉的rCNR、病变肠壁的ADC值、图像总体质量和病灶显著度。结果b值为500s/mm^(2)时,SMS-DWI序列病变与肠壁的rCNR(0.44±0.22)低于常规DWI序列(0.53±0.14),差异有统计学意义(P<0.05);b值为1000 s/mm^(2)时,SMS-DWI序列病变与肠壁的rCNR(0.48±0.20)低于常规DWI序列(0.60±0.13),差异有统计学意义(P<0.05)。SMS-DWI序列病变的ADC值与常规DWI序列的ADC值无统计学差异(P=0.185)。b值为500、1000 s/mm^(2)时,SMS-DWI序列的图像总体质量和病变显著度均无统计学差异(P>0.05)。结论MRI SMS-DWI显示克罗恩病患者结肠病变是可行的,可以有效缩短采集时间,诊断效能和ADC值与常规DWI图像相似。

Objective To investigate the feasibility of simultaneous multi-slice diffusion weighted imaging(SMS-DWI)technique in colon lesion in patients with Crohn’s disease.Methods A total of 15 patients with clinically diagnosed Crohn’s disease in our hospital were collected.All patients underwent SMS-DWI and routine DWI imaging with b values of 50,500 and 1000 s/mm^(2).Two radiologists measured the signal intensity(SI)and apparent diffusion coefficient(ADC)of the intestinal wall and erector spinal muscle of 24 lesions at SMS-DWI and conventional DWI sequences.The relative contrast to noise ratio(rCNR)of the intestinal wall and erector ridge muscle of the two sequences were calculated,and the overall image quality and lesion significance of SMSDWI and conventional DWI sequences were evaluated jointly when the b value was 500 s/mm^(2)and 1000 s/mm^(2).Paired sample t-test or Wilcoxon rank sum test was used to compare the rCNR of diseased intestinal wall and muscle,ADC value of intestinal wall,the overall quality and significance of lesions between SMS-DWI and routine DWI sequence.Results With b value 500 s/mm^(2),the rCNR of SMS-DWI lesions and intestinal wall was lower(0.44±0.22)than that of conventional DWI sequence(0.53±0.14),and the difference was statistically significant(P<0.05).When b value was 1000 s/mm^(2),the rCNR of SMS-DWI sequence lesions and intestinal wall was lower(0.48±0.20)than that of conventional DWI sequence(0.60±0.13),and the difference was statistically significant(P<0.05).ADC values of SMS-DWI sequence lesions were not statistically different from those of conventional DWI sequence(P=0.185).When b value was 500 s/mm^(2)and 1000 s/mm^(2),there was no statistical difference in overall image quality and lesion significance of SMS-DWI sequence(P>0.05).Conclusion MRI SMS-DWI is feasible to show colonic lesion in patients with Crohn’s disease.The technique can effectively shorten the acquisition time,and the diagnostic efficiency and ADC value are similar to those of routine DWI image.