WB-DWI在恶性肿瘤淋巴结转移中的应用

目的:探讨磁共振全身弥散加权成像(whole body diffusion-weighted imaging,WB-DWI)在恶性肿瘤淋巴结转移瘤中的应用价值。方法:对110例疑似恶性肿瘤淋巴结转移患者行WB-DWI检查,并于扫描后1周内对可疑骨转移部位及原发恶性肿瘤部位行常规MRI/CT检查。根据MRI/CT及临床综合诊断结果,将所有患者分为淋巴结转移组及非淋巴结转移组,对资料进行统计学分析,比较单独应用WB-DWI、MRI/CT及二者联合应用(WB-DWI+MRI/CT)在恶性肿瘤淋巴结转移中的诊断价值。分别测定淋巴结转移组及非淋巴结转移组的ADC值,比较其在良恶性病变鉴别诊断中的价值。结果:①将淋巴结按长径大小分为<2cm,2～3cm,>3cm,WB-DWI、MRI/CT及WB-DWI+MRI/CT对长径<2cm淋巴结转移的检出差异具有统计学意义。进一步两两比较,单独应用MRI/CT与WB-DWI+MRI/CT的差异具有统计学意义(χ2=6.519,P=0.011)。②ROC分析结果显示,WB-DWI+MRI/CT诊断恶性肿瘤淋巴结转移的特异度、诊断准确性、阳性预测值及阴性预测值诊断最高。③淋巴结转移组ADC值明显低于良性淋巴结病变组,在良恶性淋巴结转移鉴别诊断中具有一定作用。结论:WB-DWI是常规MRI、CT的有益补充,与MRI/CT的联合应用可以提高恶性肿瘤淋巴结转移的诊断率,结合ADC值测定,在恶性肿瘤淋巴结转移诊断和鉴别方面具有一定价值。

The utility of whole-body diffusion-weighted imaging for the detection of lymphatic metastases in malignant tumors

Objective： To prospectively and directly compare the capability of whole-body diffusion-weighted imaging （WB- DWI）, standard magnetic resonance imaging （MRI）/eomputed tomography（CT） and WBDWI with standard MRI/CT for as sessment of lymphatic metastases in malignant tumor patients. Methods： A total of 110 malignant tumor patients prospectively underwent WB-DWI, standard MRI/CT in suspicious lymphatic metastases parts and a chest CT within one week after inspec- tion if it＇s a lung cancer patients. Final diagnosis of the lymphatic metastases in each patient was determined on the basis of re- sults of all radiologie and follow up examinations. Two radiologists independently assessed all examination results and used a five-point visual scoring system to evaluate the probability of metastases. Final diagnosis based on each of the methods was made by consensus of two readers. Receiver operating characteristic（ROC） analysis was used to compare the capability for lym- phatic metastases assessment among WB-DWI, standard MRI/CT and WB-DWI with standard MRI/CT. The detection ability of lymph nodes with different size were compared with 2 tests. The differential diagnosis value of apparent diffusion coefficient （ADC） in benign and malignant lymph nodes was compared with the variance analysis. Results：①There were 60 patients with lymphatic metastases of all 110 malignant tumor patients. Lymph nodes were divided into three groups according to the length diameter（〈2 cm,2-3 cm,〉3 cm）. A statistically significant difference was found in detection of lymph nodes （〈2 cm） among WB-DWI, standard MRI/CT and WBDWI with standard MRI/CT（ X^2=6. 519, P=0. 038）. ②Area under ROC curve （Az） value of WB-DWI with standard MRI/CT（0. 955） and standard MRI/CT（0. 912）were significantly larger than that of WB-DWI （0. 932）,and the specificity,accuracy, positive and negative predictive value of WBDWI with standard MRI/CT were signifi cantly higher than others. ③The ADC value of malignant lymph nodes were significantly lower than those of benign（0.83 0. 18）× 10 3mm^2/s vs （1.50±0. 15）× 10^-3 mm^2/s]. Conclusion： WB-DWI is the beneficial supplements of standard MRI/CT. Combined with ADC value, it can be used for assessment and differential diagnosis of lymphatic metastases in malignant tumor patients.