目的探讨梯度场Z轴增益对磁 共振全身弥散加权成像(WB-DWI)图像拼 接的影响。方法 对20例骨显像证实为肿 瘤骨转移患者进行前瞻性研究，每位患者 均需行两次WB-DWI检查(序列1、2)。其中 序列2相对于序列1仅在Z轴增益上调整-5 至5，余参数与序列1保持一致。评价两种 序列检查获得图像的拼接差异，同时以骨 扫描结果为标准，比较WB-DWI与PET-CT的 诊断吻合率。结果 (1)序列2得到的拼接 图像质量评分≥3分17例，多于序列1拼 接图像质量评分≥3分(14例)，差异有统 计学意义(P＜0.05)；(2)序列2得到的拼 接图像发现可疑骨转移病灶数78个，高于 序列1可疑骨转移病灶数(65个), 差异有 统计学意义(P＜0.05)；(3)WB-DWI序列2 发现可疑骨转移数高于PET-CT发现可疑骨 转移病灶数(75个)，差异无统计学意义(P ＞0.05)。结论 适度调整梯度场Z轴增益 有助于WB-DWI图像拼接和提高图像质量， WB-DWI对肿瘤全身骨转移性疾病有很好的 诊断及鉴别诊断价值。

Objective To study the effect of gradient Z-axis gain on magnetic resonance diffusion-weighted imaging (WB-DWI) image splicing. Methods A total of twenty patients with bone metastases confirmed by bone imaging were prospectively studied. WB-DWI was performed twice in each patient (SEQ 1 and SEQ 2). Where sequence 2 is adjusted only to -5 to 5 on the Z-axis gain relative to sequence 1, and the remaining parameters are consistent with sequence 1. Evaluate the two sequences to check for splicing image differences, and the difference of diagnostic rate between WB-DWI and PET-CT based on the results of bone scan. Results (1) The splicing image quality: 17 patients scored greater than or equal to 3 points with sequence 2 more than that scored greater than or equal to 3 points with sequence 1, and the difference was statistically significant (P<0.05). (2) The number of suspected bone metastases of sequence 2 was 78, which was higher than that of sequence 1 (65), the difference was statistically significant (P<0.05). (3) WB-DWI sequence 2 found that bone metastases were significantly higher than those in the control group (PET-CT), and the number of suspected bone metastases was 78, but there was no significant difference between the two groups (P>0.05). Conclusion WB-DWI has a good diagnosis and differential diagnosis of tumor-induced bone metastatic disease. It is helpful for WB-DWI image splicing and improving the image quality.