Objective:To compare the three different acquisition techniques for diffusion-weighted imaging (DWI)of the upper abdomen at 1.5T or 3.0T.Methods:21 volunteers underwent routine MRI examination at 1.5T and 3.0T scanner (GE Signa HDx).Three DWI examinations were then performed with breath-hold,respiratory-triggered and free-breathing techniques respectively (b-value=100 and 800s/mm2 ).The DWI images were independently evaluated by two radiologists regarding image quality,image artifacts,signal-to-noise ratio (SNR)and apparent diffusion coefficient (ADC)value. Results:The image quality of respiratory-triggered DWI was better at 3.0T than 1.5T (P <0.05 ).The artifact score and image quality of free-breathing DWI were better at 1.5T than 3.0T (P <0.05).Free-breathing DWI had the highest SNR among the three techniques.SNR of the liver was lower at 3.0T than 1.5T (P <0.05).The ADC values of liver,gallblad-der,kidney and pancreas showed no statistical differences between 1.5T and 3.0T (P >0.05 ).Conclusions:DWI with re-spiratory-triggered technique can achieve better imaging quality at 3T,and DWI with free-breathing has the highest SNR. The ADC values of upper abdomen organs show no significantly differences between 1.5 and 3.0T.%目的：比较1．5T 和3．0T 上腹部磁共振扩散加权成像在屏气、呼吸触发、自由呼吸3种采集技术下得到的图像质量。方法：21名志愿者分别在 GE Signa HDx 1．5T 和3．0T 磁共振机上进行常规 MR 和包括屏气、呼吸触发、自由呼吸3种采集方式在内的 DWI 检查，b 值均为100和800。2名医师分别盲法记录、评价主观图像质量分数，图像伪影、信噪比以及表观扩散系数（ADC）值。结果：呼吸触发 DWI 3．0T 的图像质量优于1．5T（P ＜0．05），而自由呼吸 DWI 1．5T 的伪影评分和图像质量均优于3．0T（P ＜0．05）；3种采集技术中自由呼吸 DWI 的信噪比最高，3．0T DWI 中肝脏的 SNR 低于1．5T（P ＜0．05）；1．5T 和3．0T 之间正常肝脏、胆囊、肾脏和胰腺的 ADC 值均无统计学差异（P ＞0．05）。结论：3．0T 呼吸触发采集技术可以获得较好的 DWI 影像；而自由呼吸 DWI 的信噪比最高；上腹部正常脏器的 ADC 值在1．5和3．0T之间无差异。
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