扩散加权成像在鉴别诊断子宫内膜癌盆腔淋巴结性质中的应用

摘要

Purpose To compare the accuracy of routine MR and diffusion-weighted imaging (DWI) in the qualitative diagnosis of pelvic lymph nodes in patients with endometrial cancer, and to evaluate the relationship between apparent diffusion coefficient (ADC) value and the cellularity. Materials and Methods Fifty-five patients with pathologically proven endometrial cancer underwent routine MRI and DWI. All patients were divided into metastatic lymph nodes (metastatic group) and inflammatory lymph nodes (inflammatory group) according to the histopathology. The size of lymph nodes in both groups were measured on T2WI, the signal intensity and ADC value were measured on T2WI, DWI and ADC map. With pathology as the criteria, the quantitative diagnosis of long diameter (L), short diameter (S), L/S, signal intensity on T2WI and DWI (SIT2WI, SIDWI) and ADC value was evaluated, and the correlation between ADC value and cell density was analyzed. Results 57 metastatic pelvic lymph nodes and 102 inflammatory lymph nodes were detected in 55 patients. No difference in the size, signal intensity on T2WI or DWI was observed between the two groups (L: t=1.63;S t=2.09; L/S: t= -1.59;SIT2WI:t=-0.97;SIDWI:t=-0.74, P>0.05). The ADC value of the metastatic group was statistically lower than that of inflammatory group of both groups (t=-8.73, P<0.001). When the ADC value was 1.04×10-3 mm2/s, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 93%, 93%, 95%, 90%, 93%, respectively. There was a negative correlation between ADC value and cell density (r=-0.674, P<0.001). Conclusion ADC value has a high diagnostic efficacy in differentiating metastatic pelvic lymph nodes in patient with endometrial cancer. Cell density may be the most important factor that affects the discrepancy of ADC value of lymph nodes between the two groups.%　　目的比较常规MR序列与扩散加权成像（DWI）判断子宫内膜癌盆腔淋巴结性质的准确性，评价表观扩散系数（ADC）值与细胞密度的相关性。资料与方法55例经手术病理证实的子宫内膜癌患者行常规MR序列和DWI检查，依照病理结果将盆腔淋巴结分为转移性淋巴结（转移组）和炎性淋巴结（炎性组）。在T2WI上测量两组淋巴结的大小，在T2WI、DWI和ADC图上测量其信号强度和ADC值，以病理结果为标准，评价长径（L）、短径（S）、长/短径（L/S）、T2WI上信号强度（SIT2WI）、DWI上信号强度（SIDWI）和ADC值对淋巴结性质的诊断效能，并分析ADC值与细胞密度的相关性。结果55例患者共检出57枚转移性淋巴结和102枚炎性淋巴结，两组淋巴结大小及T2WI和DWI上信号强度差异均无统计学意义（L：t=1.63；S：t=2.09；L/S：t=―1.59；SIT2WI：t=―0.97；SIDWI：t=―0.74；P>0.05）；转移组ADC值明显低于炎性组（t=－8.73, P<0.001）。当ADC值取1.04×10-3 mm2/s时，诊断效能最大，其诊断敏感度、特异度、阳性预测值、阴性预测值和准确度分别为93%、93%、95%、90%、93%；两组淋巴结ADC值与细胞密度呈负相关（r=－0.674, P<0.001）。结论ADC值对子宫内膜癌盆腔淋巴结是否转移具有较高的诊断价值，细胞密度可能是影响两组淋巴结ADC值差异的关键因素。