探讨RS-EPI-DWI成像在乳腺癌腋窝淋巴结检查中的价值

Study on RS-EPI-DWI’s Value in Axillary Lymph Node Examination of Breast Cancer

目的探讨分段读出扩散加权成像(Readout-Segmented Echo-Planar Imaging Diffusion-Weighted Imaging,RS-EPI-DWI)在乳腺癌腋窝淋巴结检查中的优势。方法分析43例经病理证实的检查前未做任何治疗的乳腺癌并腋窝淋巴结转移患者的扩散加权成像(Diffusion Weighted Imaging,DWI)的图像,采用西门子3.0T Skyra磁共振扫描仪进行轴位单次激发平面回波扩散加权成像(Single-Shot Echo-Planar Imaging Diffusion-Weighted Imaging,SS-EPI-DWI)序列及RS-EPI_DWI序列扫描,测量b值为800 s/mm2的DWI图像上腋窝淋巴结信号值及图像轴位区域的噪声值,计算出图像信噪比(Signal to Noise Ratio,SNR)和对比噪声比(Contrast to Noise Ratio,CNR),在表观扩散系数(Apparent Diffusion Coefficient,ADC)图上测量淋巴结的ADC值,比较两组ADC值差异,对两组图像关于腋窝淋巴结显示情况进行主观分级。结果RS-EPI_DWI较SS-EPI_DWI图像的SNR(t=11.880,P<0.001)及CNR(t=10.558,P<0.001)值高,对SS-EPI_DWI和RS-EPI_DWI ADC图转移淋巴结ADC值的检测结果无统计学差异(t=-0.477,P=0.636>0.05)。RS-EPI_DWI图像分级明显优于SS-EPI_DWI图像(t=-6.457,P<0.01),RS-EPI_DWI较SS-EPI_DWI图像在腋窝淋巴结显示上更具优势。结论RS-EPI_DWI较SS-EPI-DWI图像质量更佳,对于腋窝淋巴结显示更具临床价值,RS-EPI_DWI与SS-EPI_DWI所测淋巴结ADC值无明显差异,同时RS-EPI_DWI的ADC图对于小病灶的ADC值的测值能力优于SS-EPI_DWI。

Objective To investigate the advantage of readout segmented echo planar imaging diffusion weighted imaging(RS-EPI-DWI)in axillary lymph node examination of breast cancer.Methods The diffusion weighted imaging(DWI)images of 43 patients with breast cancer and axillary lymph node metastasis confirmed by pathology were analyzed.All patients were scanned by Siemens 3.0T Skyra MRI scanner with single shot echo planar imaging diffusion weighted imaging(SS-EPI-DWI)sequence and RS-EPI_DWI sequence.The signal to noise ratio(SNR)and contrast to noise ratio(CNR)were calculated by measuring the signal to noise ratio(SNR)and the noise value of the axial region on DWI images with b value of 800 s/mm2.The ADC values of lymph nodes were measured on the apparent diffusion coefficient(ADC)map,and the differences of ADC values between the two groups were compared.The subjective classification of axillary lymph nodes in the two groups of images was made.Results The SNR(t=11.880,P<0.001)and CNR(t=10.558,P<0.001)in RS-EPI_DWI were significantly higher than those in SS-EPI_DWI,but there was no significant difference in ADC value of metastatic lymph nodes between SS-EPI_DWI and RS-EPI_DWI(t=-0.477,P=0.636>0.05).In addition,the image grading of RS-EPI_DWI was significantly better than that of SS-EPI_DWI(t=-6.457,P<0.01),and the images of RS-EPI_DWI group had more advantages than SS-EPI_DWI in displaying axillary lymph nodes.Conclusion The image quality of RS-EPI_DWI is better than that of SS-EPI_DWI,and has more clinical value for axillary lymph node display.There is no significant difference in ADC value between RS-EPI_DWI and SS-EPI_DWI.at the same time,ADC value of RS-EPI_DWI is better than that of SS-EPI_DWI for small lesions.