分段读出扩散加权成像在鼻咽癌检查中的价值

目的探讨分段读出扩散加权成像(RS-EPI DWI)相对于单次激发平面回波扩散加权成像(SS-EPI DWI)在鼻咽癌检查中的价值。方法收集30例经病理证实的未做任何治疗的鼻咽癌患者,采用Siemens 3.0 T Skyra磁共振扫描仪对患者常规平扫加增强扫描基础上加做鼻咽的轴位RS-EPI DWI及SS-EPI DWI序列,分别计算出鼻咽肿瘤区域的信噪比(SNR)、对比噪声比(CNR),以T_1增强轴位图像为参考,计算鼻咽层面图像的变形百分比,测量鼻咽肿瘤长、短径,比较SS-EPI DWI、RS-EPI DWI图像上肿瘤大小的准确性,比较颅底层面磁敏感伪影幅度。结果RS-EPI DWI较SS-EPI DWI图像的SNR(t=34.074,P0.01)、CNR(t=23.120,P0.01)值高,图像变形较轻,相同解剖层面,RS-EPI DWI图像测出的肿瘤大小更接近增强后T1轴位上病灶大小,颅底层面RS-EPI DWI图像磁敏感伪影明显较弱(b值为0 s/mm~2时t=10.634,P0.01,b值为1000 s/mm~2时t=8.219,P0.01),两名医师分别对SS-EPI DWI、RS-EPI DWI的ADC图病灶区进行测值,两组测值在判断病灶扩散受限上统计学差异(t=0.00,P=1.000.05)。结论分段读出扩散加权成像较传统的弥散加权成像图像质量更佳,其临床应用更有价值,对于诊断的准确性具有积极的作用。

Comparison of readout-segmented and single-shot echo-planar imaging diffusion-weighted imaging in nasopharyngeal carcinoma

Objective To compare the clinical utility of readout-segmented echo-planar imaging diffusion-weighted imaging (RS-EPI DWI) with single-shot echo-planar imaging diffusion-weighted imaging (SS-EPI DWI)in nasopharyngeal carcinoma.Methods 30 patients with pathologically confirmed nasopharyngeal carcinoma underwent pre-treatment contrast-enhanced 3 T MRI of nasopharynx including SS-EPI DWI and RS-EPI DWI.The signal-to-noise ratio (SNR) and contrast to noise ratio (CNR),tumor volume and geometric distortion were recorded.The accuracy and susceptibility artifacts were compared between SS-EPI DWI and RS-EPl DWI.Results The SNR (t=34.074,P＜0.01),CNR (t=23.120,P＜0.01) and geometric distortion of RS-EPI DWI were better than that of SS-EPI DWI images.RS-EPI DWI significantly decreased susceptibility artifacts seen on SS-EPI DWI to produce high-resolution images without distortion.Lesions were more accurately evaluated with RS-EPI DWI on T1-weighted images at the same anatomic location (b=0 s/mm2:t=10.634,P＜0.01,b=1000 s/mm2:t=8.219,P＜0.01).There was no significant difference of the ADC values between the RS-EPI DWI and the SS-EPI DWI (t=0.00,P=1.00＞0.05).Conclusion RS-EPI DWI has superior image quality to SS-EPI DWI in nasopharyngeal carcinoma.