肺恶性肿瘤和实性良性病变扩散加权成像技术初探  

Diffusion-weighted imaging in malignant pulmonary tumors and solid benign lesions

作　　者：刘海东[2] 于铁链[1] 刘颖[1] 叶宁[1] 

机构地区：[1]天津医科大学总医院放射科,300052 [2]天津市中心妇产科医院放射科

出　　处：《国际医学放射学杂志》2010年第3期240-244,共5页International Journal of Medical Radiology

摘　　要：目的探讨相控阵线圈联合并行采集空间敏感度编码技术（ASSET）扩散加权成像（DWI）用于检查肺内恶性肿瘤和实性良性病变的可行性,并优化DWI检查扫描参数。方法 12例肺良性病变和50例肺恶性肿瘤（共66个病灶）被纳入研究,其中最初就诊的12例构成不同DWI方案实验组（组1）,全部62例病例构成b值实验组（组2）。组1采用4种不同DWI扫描方案：A,ASSET＋自由呼吸＋4NEX;B,ASSET＋自由呼吸＋1NEX;C,ASSET＋屏气＋1NEX;D,常规DWI＋屏气＋1NEX;比较各方案的信噪比（SNR）和对比噪声比（CNR）,从中选出最佳扫描方案。组2应用筛选出的最佳扫描方案行不同b值（200、300、500、700和1000s/mm2）DWI检查,比较各b值组的SNR、CNR、ADC值以及ADC值对肺良恶性病变的鉴别诊断效能,从中选出最佳b值。结果组1内4种扫描方案SNR和CNR差异均有统计学意义（P均为0.000）,且方案A最大。组2中,不同b值组间SNR差异有统计学意义（P=0.000）,而CNR差异无统计学意义（P〉0.05）;良性病变组和恶性病变组ADC值均随b值增加而逐渐变小,差异有统计学意义（P=0.039,P=0.000）;从200～1000s/mm2不同b值的4组的ROC曲线下面积（Az）分别为0.608、0.537、0.785、0.583、0.576,均有诊断意义（Az〉0.5）,b取500s/mm2时获得的ADC值的诊断效能最大,此时ADC值鉴别良恶性病变的最佳阈值为1.400×10-3mm2/s,敏感度和特异度分别为83.3%和74.1%。结论在1.5TMR设备上,采用相控阵线圈和ASSET技术对肺恶性肿瘤和良性实性病变行DWI检查切实可行;在自由呼吸状态下采用b值为500s/mm2、激励次数（NEX）为4时能够获得满意的胸部DWI影像。Objective To evaluate the feasibility of diffusion-weighted imaging（DWI） with array spatial sensitivity encoding technique（ASSET） and phased-array coil in malignant pulmonary tumors and solid benign lesions,and to optimalize imaging parameters.Methods Twelve benign lesions and fifty malignant pulmonary lesions with sixty-six lesions were enrolled in this study.Twelve of them with twelve lesions constituted group one,who underwent DWI using 1.5 T MR scanner with four different scan methods.The scan methods consisted of method A using ASSET,free breathing and four NEX,method B using ASSET,free breathing and one NEX,method C using ASSET,breath-hold and one NEX,and method D using conventional DWI without ASSET,breath-hold and one NEX.Group two was composed of all sixty-two patients,they all underwent DWI with different b values（200,300,500,700,1 000 s/mm2）.Results In group one,signal to noise ratio（SNR） and contrast to noise ratio（CNR） of method A were best compared to other methods,and the difference had statistical significance（P=0.000,P=0.000）.In group two,with b values changing from low to high,SNR of DWI images was 53.3,45.9,35.7,26.9,21.4 and CNR was 3.77,4.22,4.36,3.77,2.90 respectively.The SNR differed significantly among different b values（P0.001）,but CNR did not（P0.05）.ADC values of malignant pulmonary tumors and solid benign lesions reduced gradually with b value increasing,and the differences had statistical significance（P0.001）.By ROC curve analysis,the ADC values obtained from each b value were profit for differentiation between benign and malignant tumors.The area under ROC curve with b value of 500 s/mm2 was the largest.The optimal ADC threshold value of 1.400×10-3 mm2/s yielded sensitivity 83.3% and specificity 74.1%.Conclusion DWI examination with phased-array body coil and ASSET is feasible for assessing pulmonary malignant tumors and solid benign lesions,and the optimal b value is 500 s/mm2.

关 键 词：肺 磁共振成像 扩散加权成像 表观扩散系数 

分 类 号：R734.2[医药卫生—肿瘤]