| 唐磊,张晓鹏,孙应实,李英.胃癌磁共振扩散加权成像:并行采集联合分次屏气多信号平均技术的临床研究[J].中国医学影像技术,2005,21(12):1830~1834 |
| 胃癌磁共振扩散加权成像:并行采集联合分次屏气多信号平均技术的临床研究 |
| Diffusion-weighted MR imaging of gastric cancer: study of parallel imaging combined with separate breath-holds and multi-NEX technique |
| 投稿时间：2005-09-06 修订日期：2005-11-25 |
| DOI： |
| 中文关键词: 胃肿瘤 磁共振成像 扩散加权成像 并行采集 |
| 英文关键词:Stomach neoplasms Magnetic resonance imaging Diffusion-weighted imaging Parallel imaging |
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| 中文摘要: |
| 目的 探索实现胃癌磁共振扩散加权成像(DWI)的技术因素,评价胃癌DWI的临床应用价值。方法 扩散加权单次激发平面回波成像(SS-EPI)序列连续检查胃癌患者53例,其中前期17例进行ASSET-DWI成像方法研究,结合分次屏气多信号平均技术,以肿瘤显示、伪影分级、对比噪声比(CNR)为评价标准,比较有无ASSET及不同信号平均次数(NEX)与ASSET搭配所得DWI图像的质量,确定成像参数;利用确定序列对后续36例胃癌进行成像研究,确定胃癌及非癌胃壁的DWI影像学表现及ADC值范围。扩散敏感梯度取b=0、1000 s/mm2。结果 ASSET-DWI组较无ASSET组成像速度提高,相关伪影(磁敏感伪影、化学位移伪影及Ghost伪影)轻且图像基本无变形(P<0.01);分次屏气采集对ADC值计算无影响(P>0.05);分次屏气多信号平均(4 NEX)采集,可基本消除ASSET相关伪影,具备良好的对比噪声比。胃癌癌肿在DWI图上表现为稳定的高信号,平均ADC值为(1.17±0.22)×10-3 mm2/s,非癌胃壁表现为低信号,平均ADC值为(1.94±0.28)×10-3 mm2/s,二者差异有统计学意义(P<0.01);以ADC值<1.46×10-3 mm2/s作为判定胃癌的标准,敏感性97.0%,特异性90.9%。结论 8通道体部相控阵线圈联合ASSET技术及分次屏气多信号平均采集,实现了胃癌高b值扩散加权成像;ADC值可作为胃癌诊断的辅助指标。 |
| 英文摘要: |
| Objective To explore the technical feasibility of diffusion-weighted MR imaging (DWI) in gastric cancer (GC), and evaluate its clinical use. Methods Fifty-three patients with GC were examined with single-shot echo planar imaging (SS-EPI) sequence at 1.5T. The image quality of ASSET-DWI combined with different number of excitations (NEXs) were evaluated in 17 cases to determine the imaging parameters, concerning to the tumor detectability, gradation of artifacts and contrast-to-noise ratio (CNR). Then 36 cases were imaged with the determined sequence to get the apparent diffusion coefficient (ADC) values of GC and non-cancerous gastric wall. The b values were 0 and 1000 s/mm2. Results The acquisition time of DWI was reduced after associating with ASSET, and the EPI-related artifacts and image distortion were slighter than that without ASSET . There was no influence of separate breath-holds on the ADCs meacurement (P>0.05). Separate breath-holds with multi-NEX technique could eliminate the ASSET-related artifacts and get high CNR images. The GC appeared high signal on DWI with an ADC value of (1.17±0.22)×10-3 mm2/s, which had statistical difference to the non-cancerous gastric wall . Taking ADCs<1.46×10-3 mm2/s as a standard for the diagnosis of GC, the sensitivity is 97.0% and the specificity is 90.9%. Conclusion The diffusion-weighted MR imaging of GC was achieved through the combination of ASSET and separate breath-hold with multi-NEX technique. The ADC can be an accessorial index in the diagnosis of GC. |
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