目的：探讨恶性孤立性肺小结节的影像学征象。方法：收集孤立性肺小结节病例908例,分析其肿瘤微血管CT成像征、血管集束征、分叶征及毛刺等影像学征象,并寻找恶性肺小结节特征性的影像学征象。结果：908例肺小结节病例中恶性825例,良性83例。恶性肺小结节中肿瘤微血管CT成像征、血管集束征和毛刺的检出率高于良性肺小结节（均P<0.001）。按恶性肺小结节密度分的3组中肿瘤微血管CT成像征、血管集束征、分叶征和毛刺的检出率均不同（P<0.001）。随着肺小结节密度升高,血管集束征、分叶征和毛刺的检出率也增加（趋势P<0.001）。按腺癌浸润深度分的3组中肿瘤微血管CT成像征、血管集束征、分叶征和毛刺的检出率均不同（P<0.001）。随着浸润加深,肿瘤微血管CT成像征、血管集束征、分叶征和毛刺的检出率也增加（趋势P<0.001）。结论：肿瘤微血管CT成像征在非实性结节和部分实性结节定性诊断中起提示作用,而血管集束征、分叶征及毛刺在实性结节的定性诊断中更有价值,这些影像学征象将在肺小结节定性诊断中发挥作用。

Objective To analyze the imaging characteristics of malignant solitary pulmonary nodule (SPN). Methods Totally 908 cases of SPN were collected. The imaging features of SPN were analyzed, including tumor microvascular CT sign, vascular convergence, lobulation sign and spiculation. Results In 908 SPN cases, 825 were malignant and 83 were benign. The detection rates of tumor microvascular CT sign, vascular convergence and spiculation were higher in malignant SPN than those in benign SPN (P<0.001). The detection rates of these features were different when malignant SPN were divided into three groups according to different SPN density(P<0.001), and they increased following SPN density increasing (P<0.001). In addition, the detection rates of these features were different when malignant SPN were divided into three groups according to the invasion depth of adenocarcinoma (P<0.001), and they also increased following the deepening of infiltration (P<0.001). Conclusions Tumor microvascular CT signs play an important role in the diagnosis of pure ground glass nodules and part of solid nodules, while vascular convergence, lobulation sign and spiculation are more valuable in qualitative diagnosis of solid nodules. These imaging features also show the diagnostic value in benign and malignant SPN.